Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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41465 Publications

Cadmium sorption on alumina nanoparticles, and mixtures of alumina and smectite: An experimental and modelling study

Mayordomo, N.; Missana, T.; Alonso, U.

Cadmium (Cd) is one of the most toxic transition metals for living organisms. Thus, effective measures to remediate Cd from water and soils need to be developed. Cd immobilization by alumina, and mixtures of alumina and smectite have been analyzed experimentally and theoret-ically by sorption experiments and sorption modelling, respectively. Cd aqueous removal was dependent on pH and Cd concentration, being maximum for pH>7.5. A two-site non-electrostatic sorption model for Cd sorption on alumina was developed and it successfully reproduced the experimental Cd immobilization on alumina. Cd sorption on mixtures of alumina and smectite depended on pH, ionic strength, and alumina content in the mixture. Cd removal in mixtures increased when alumina content increased at high pH and ionic strength values. On the contrary, Cd sorption decreased when alumina content increased under acidic conditions and low ionic strength due to the dissolution of alumina and the release of Al³⁺ into the suspension. Cd sorp-tion model on mixtures of alumina and smectite was reproduced by considering the individual Cd sorption models for alumina and smectite. The model of Cd sorption on mixtures was addi-tive when the competition of Al³⁺ with Cd²⁺ for cation exchange in smectite was included.

Keywords: Cd; sorption model; retention; immobilization; heavy metals; Al2O3

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Permalink: https://www.hzdr.de/publications/Publ-37488


β1 integrin mediates unresponsiveness to PI3Kα inhibition for radiochemosensitization of 3D HNSCC models

Korovina, I.; Elser, M.; Borodins, O.; Seifert, M.; Willers, H.; Cordes, N.

Phosphoinositide 3-kinase (PI3K)-α represents a key intracellular signal transducer involved in the regulation of key cell functions such as cell survival and proliferation. Excessive activation of PI3Kα is considered one of the major determinants of cancer therapy resistance. Despite preclinical and clinical evaluation of PI3Kα inhibitors in various tumor entities, including head and neck squamous cell carcinoma (HNSCC), it remains elusive how conventional radiochemotherapy can be enhanced by concurrent PI3K inhibitors and how PI3K deactivation mechanistically exerts its effects. Here, we investigated the radiochemosensitizing potential and adaptation mechanisms of three PI3Kα inhibitors, Alpelisib, Copanlisib and AZD8186, in eight HNSCC models grown under physiological, three-dimensional matrix conditions. We demonstrate that all three inhibitors enhance radio- and radiochemosensitivity in the majority of HNSCC cell models (= responders) in a manner independent of PIK3CA mutation status. However, Alpelisib promotes MAPK signaling in non-responders compared to responders without profound impact on Akt, NFκB, TGFβ, JAK/STAT signaling and DNA repair. Bioinformatic analyses identified unique gene mutations associated with extracellular matrix to be more frequent in non-responder cell models than in responders. Finally, we demonstrate that targeting of the cell adhesion molecule β1 integrin on top of Alpelisib sensitizes non-responders to radiochemotherapy. Taken together, our study demonstrates the sensitizing potential of Alpelisib and other PI3K inhibitors in HNSCC models and uncovers a novel β1 integrin-dependent mechanism that may prove useful in overcoming resistance to PI3K inhibitors.

Keywords: HNSCC; PI3K; beta1 Integrin; Targeting; Radiochemosensitization

Permalink: https://www.hzdr.de/publications/Publ-37487


Data publication: Numerische Untersuchung der Rayleigh-Bénard-Konvektion in einem Flüssigmetall unter dem Einfluss einer zeitlich modulierten gezeitenartigen Kraft

Röhrborn, S.

Simulationsdaten der Dissertation: "Numerische Untersuchung der Rayleigh-Bénard-Konvektion in einem Flüssigmetall unter dem Einfluss einer zeitlich modulierten gezeitenartigen Kraft"

Keywords: Rayleigh-Bénard; Magnetohydrodynamics; liquid metal flow; CFD; electromagnetic forcing; Flüssigmetall; Elektromagnetuische Anregung

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Permalink: https://www.hzdr.de/publications/Publ-37486


Steam Line Break Analysis in NuScale SMR with the Coupled System Code ATHLET-DYN3D in the Framework of the EU H2020 McSAFER

Diaz Pescador, E.; Jobst, M.; Grahn, A.; Kliem, S.

The small modular reactor (SMR) NuScale is modelled by Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in the framework of the EU H2020 McSAFER project. NuScale is a SMR of integral pressurized water reactor (iPWR) type, operated by light water driven by natural circulation in all operation modes. This work summarizes the modelling approach of NuScale SMR with the coupled thermalhydraulic/neutronic code ATHLET-DYN3D. The 3-D neutronic calculation is performed with a XS-library developed with Serpent based on 4-neutron group homogenized nuclear constants for fuel and heavy reflector. The paper presents results and discussion from a non-isolable double-ended steam line break (SLB) sequence, based on the Design Certification Application (DCA) report. The simulation results at steady-state show agreement with the reference values from the DCA report. The transient calculation shows that both steam generators (SGs) boil-off and the reactor is tripped upon “low main steam pressure” function. The rapid depressurization and high steam rates towards the break lead to enhanced primary-tosecondary heat removal. However, the reactor symmetry imposed by the arrangement of the two compact SGs enhances flow mixing and limits coolant temperature reduction at the core inlet, thereby preventing a
power excursion and highlighting the inherent safety of this reactor design. Acceptance criterion is met
regarding pressure increase below acceptable limits inside the intact SG after steam isolation valve closure.

Keywords: NuScale; SMR; ATHLET-DYN3D; SLB; McSAFER

  • Contribution to proceedings
    20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-20), 20.-25.08.2023, Washington DC, United States of America
  • Lecture (Conference)
    20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-20), 20.-25.08.2023, Washington DC, United States of America

Permalink: https://www.hzdr.de/publications/Publ-37485


In-bulk temperature profile mapping using Fiber Bragg Grating in fluids

Su, S.; Niu, T.; Vogt, T.; Eckert, S.

In this study we investigate the capabilities of Fiber Bragg Gratings (FBG) sensors to
measure temperature variations in the bulk of liquids. In particular, we want to show to what extent
the utilisation of optical glass fibers without encapsulation can fulfill the requirements with regard to
robustness and measurement accuracy. We built an experimental test setup as a benchmark, in which
23 FBG measuring positions are instrumented in parallel with thermocouples for validation. We
present a special assembly procedure in which the fiber is placed under a defined tension to improve
its stiffness and immobility for given flow conditions. We propose the application of a single FBG
sensor as a strain reference measuring the strain effect in real time and allowing for accurate relative
temperature measurements at the other FBG sensor points. The further addition of a well-calibrated,
strain-independent thermometer at the reference FBG provides satisfactory absolute temperature
data. We apply this method on two test cases: (i) a stable gradient in the liquid metal GaInSn and (ii)
a local source of heat in water. We succeeded in accurately tracking the temperature variation both
spatially and temporally.

Keywords: optical fiber; fiber Bragg Grating (FBG); temperature sensor; in-bulk measurement; multiplexing; temperature mapping

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Permalink: https://www.hzdr.de/publications/Publ-37484


Kontaktlose Materialidentifikation und Digitalisierung für die Realisierung geschlossener Stoffkreisläufe; Acamonta 2022

Röder, C.; Fuchs, M.; Abend, T.; Beyer, J.; Schüler, N.; Lorenz, S.; Dornich, K.; Gloaguen, R.; Heitmann, J.

Auf eine der drängendsten Fragen unserer modernen Gesellschaft, nämlich nach einem nachhaltigen, verantwortungsbewussten Umgang mit unseren natürlichen Rohstoffquellen, ist der Aufbau einer effizienten Kreislaufwirtschaft eine mögliche Antwort. Den Ressourceneinsatz, die Emissionen und den Energieverbrauch gilt es durch den Einsatz geschlossener Stoffkreisläufe zu minimieren. Das bedeutet, dass wir uns neben einer effizienten Nutzung der Rohstoffe auch mit einer exponentiell steigenden Abfallmenge auseinandersetzen müssen. Bisher wird allerdings nur ein kleiner Anteil aller Abfälle recycelt. Ein Grund dafür ist die zunehmende Komplexität der global anfallenden Recycling-Stoffströme, die eine rasche Weiterentwicklung der Inline-Rohstoffcharak-
terisierung unabdingbar macht.

Keywords: Rohstoffe; Charakterisierung; Recycling

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 29(2022)1, 23-26

Permalink: https://www.hzdr.de/publications/Publ-37483


Einzigartige Forschungsinfrastruktur für die Prozessmetallurgie - Das neue Metallurgie-Technikum am Helmholtz Institut Freiberg für Ressourcentechnologie; Acamonta 2021

Recksiek, V.; Bestian, M.; Kelly, N.

Am 9. September 2021 wurde das neugebaute Metallurgie-Technikum am Standort des Helmholtz-Instituts Freiberg für Ressourcentechnologie (HIF), das
zum Helmholtz-Zentrum Dresden-Rossendorf (HZDR) gehört und eine gemeinsame Gründung des HZDR und der TU Bergakademie Freiberg (TU BAF) ist, eingeweiht. In der neuen Versuchshalle werden künftig Forschungsergebnisse zur pyro- bzw. hydrometallurgischen Rückgewinnung wirtschaftsstrategischer Metalle zum (Wieder-) Einsatz in modernen Schlüsseltechnologien aus dem Labor- in den Pilotmaßstab überführt und so für den Transfer in die Industrie vorbereitet. Dazu werden innovative Verfahren miteinander kombiniert und digital untereinander vernetzt. Das Technikum bietet damit exzellente Voraussetzungen, um neue Technologien und Prozesse zu erproben, zu automatisieren und zu optimieren.

Keywords: Metallurgie; Technikum; Freiberg

Involved research facilities

  • Metallurgy Technical Centre
  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 28(2021)1, 100-100

Permalink: https://www.hzdr.de/publications/Publ-37482


Neue Gangstudien bieten systemisches Verständnis für die Entstehung hydrothermaler Lagerstätten im Erzgebirge; Acamonta 2021

Burisch-Hassel, M.; Frenzel, M.; Guilcher, M.; Swinkels, L. J.; Haschke, S.; Reinhardt, N.; Gutzmer, J.

Als Professor der Geognosie an der Bergakademie Freiberg gilt Bernhard von Cotta als Begründer der Erzlagerstättenlehre. Dieser Ruf wird zumeist zurückgeführt auf die Publikation des Lehrbuchs „Die Lehre von den Erzlagerstätten" im Jahr 1850 (von Cotta, 1859). Darüber hinaus hat Prof. von Cotta aber auch durch die Publikation der als „Gangstudien“ betitelten vier Bände in den Jahren 1850-1862 Herausragendes für die Erzlagerstättenlehre geleistet. Im Vorwort zum ersten Band definiert von Cotta sehr klar als Zweck der Gangstudien „über die Bedingungen der Erzführung womöglich einiges Licht zu verbreiten; also Materialien zu einer wissenschaftlichen Wünschelruthe zu liefern, welche künftig dem Bergmann auf seinen dunklen Pfaden als eine Leitschnur dienen könnte.” Motiviert wurde die Publikation der Gangstudien dabei insbesondere durch die proaktive Rolle des Oberbergamts, welches „eine sorgfältige Untersuchung der hiesigen Erzgänge und vorzüglich ihrer Veredelungs- oder Verunedelungsursachen angeordnet” hatte. Daher richtete von Cotta den Fokus der Gangstudien zunächst klar auf die Bildung der Erzlagerstätten in der Region. In der durch Bernhard von Cotta zusammengestellten
Publikationsreihe findet sich in der Folge eine große Zahl von Beiträgen, welche durchaus als bahnbrechend für ihre Zeit gelten.
Die vorerst letzte Phase des Bergbaus in Freiberg endete im Jahre 1969; der Bergbau im Erzgebirge fand mit der deutschen Wiedervereinigung im Jahr 1991 ein unvermitteltes Ende. In den seither vergangenen Jahrzehnten hat die Kenntnis um die Entstehung der Erzlagerstätten im Erzgebirge mit modernen geowissenschaftlichen Erkenntnissen und Konzepten nicht mitgehalten. Dadurch ging viel Kompetenz verloren – aus modellbasierten Annahmen früherer Bearbeiter wurden „in Stein gehauene” Paradigmen, die weitestgehend unkritisch weitergegeben wurden. Mit dem Ziel, diesen offensichtlichen und eklatanten Missstand zu beheben, wurde im Jahr 2018 die ESF Nachwuchsforschergruppe „Mineral Systems Analysis” gegründet. Ermöglicht durch öffentliche Fördermittel der Europäischen Union und des Freistaats Sachsen haben sich seither zwei Doktorandinnen und zwei Doktoranden, flankiert durch eine Vielzahl von Master- und Bachelor-Student*innen unter der Leitung von Mathias Burisch mit der Entstehung verschiedener hydrothermaler Lagerstättentypen im Erzgebirge befasst. Die Arbeiten der Nachwuchsgruppe am Institut für Mineralogie der TU Bergakademie Freiberg wurden durch Max Frenzel und Jens Gutzmer am Helmholtz-Institut Freiberg für Ressourcentechnologie unterstützt. Die Forschung basierte dabei zum Teil auf dem Studium von hervorragenden Proben der geowissenschaftlichen Sammlungen der TU Bergakademie Freiberg, der Wismut GmbH und dem Bohrkernarchiv des
Sächsischen Landesamts für Umwelt, Landwirtschaft und Geologie. Die enge und vertrauensvolle Zusammenarbeit mit den Firmen, die aktuell im Bereich von Rohstofferkundung und -abbau im Erzgebirge beteiligt sind, lieferte einen weiteren wichtigen Baustein für den Erfolg der Gruppe. Die Entwicklung eines modernen Verständnisses der räumlich-zeitlichen Entwicklung der Erzlagerstätten im Erzgebirge und die Integration der lagerstättenbildenden Prozesse mit relevanten Prozessen der regional- und lokalgeologischen Entwicklung stand im Fokus der Forschung – ganz im Sinne von Bernhard von Cotta. Daher sind die wichtigsten Resultate der Arbeit der Nachwuchsforschergruppe, die im Folgenden vorgestellt werden sollen, in das aktuelle Verständnis der geotektonischen Entwicklung eingebettet. Hier werden insgesamt 10 peer-review Artikel der Mineral Systems Analysis Gruppe zusammengefasst, die alle in der Referenzliste aufgeführt sind und bei Interesse zur weiteren Vertiefung gelesen werden können.

Keywords: Erzgebirge; Lagerstättenlehre; Mineral Analysis Group

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 28(2021)1, 83-87

Permalink: https://www.hzdr.de/publications/Publ-37481


Helios Lab - Ein gemeinsames Labor zwischen Helmholtz-Institut Freiberg für Ressourcentechnologie und der Technischen Universität Bergakademie Freiberg; Acamonta 2021

Gloaguen, R.; Lorenz, S.

Wenn wir die negativen Auswirkungen menschlicher Aktivitäten auf Klima und Umwelt reduzieren wollen, müssen wir uns zwangsläufig mit einer exponentiell steigenden Abfallmenge auseinandersetzen. Solche Abfälle beinhalten nicht nur die Reste unseres alltäglichen Konsums wie z. B. Elektroschrott. Im Bergbau wird beispielsweise nur ein kleiner Teil des geförderten Gesteins tatsächlich für die Gewinnung neuer Rohstoffe genutzt, der größere Rest landet auf Halden. Zusätzlich zu solchen primären Abfällen fallen große Mengen an Sekundärabfällen wie Verbrennungsrückstände und Schlacken an. Ein besseres Recycling unserer Reststoffe ist zu einer dringlichen Aufgabe geworden, und auch wenn eine vollständige Kreislaufwirtschaft in Zukunft Utopie bleiben muss, so sollten wir uns doch so viel wie möglich daran annähern.

Keywords: Recycling; Sortierung; Charakterisierung; Rohstoffe

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 28(2021)1, 37-38

Permalink: https://www.hzdr.de/publications/Publ-37480


recomine - Ganzheitliche Lösungsansätze für Bergbaualtlasten durch Kombination von Umwelt-, Ressourcentechnologie und Digitalisierung; Acamonta 2021

Büttner, P.; Engelhardt, J.

Neue Wege im Umgang mit Bergbaualtlasten
In den vergangenen zehn Jahren befassten sich mehrere nationale und europäische Förderprogramme mit dem Ressourcenpotenzial von Bergbauabfällen (Grobbergematerial, Spülhalden und Hüttenschlacken), wobei der Schwerpunkt auf der Erschließung neuer Quellen für kritische Rohstoffe lag, die von
der Europäischen Kommission als äußerst wichtig für die europäische Hightech-Industrie definiert wurden. Sie beruhen auf der europäischen und nationalen Ressourcenstrategie. Eines dieser Programme in Deutschland war das vom Bundesministerium für Bildung und Forschung (BMBF) geförderte Programm
„r3 - Strategische Metalle und Mineralien - Innovative Technologien für Ressourceneffizienz", das im Jahr 2012 startete. Ziel war es, die Versorgung der deutschen Wirtschaft mit strategisch bedeutsamen Metallen und Mineralien zu sichern und Projekte in den Bereichen Recycling, Substitution und reduziertem Ressourcenverbrauch, Urban Mining und Methoden zur Bewertung der Ressourceneffizienz zu fördern.

Keywords: recomine; Bergbaualtlasten; Ressourcentechnologie

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 28(2021)1, 32-33

Permalink: https://www.hzdr.de/publications/Publ-37479


Innovationsplattform für die Kreislaufwirtschaft der Zukunft - Das Helmholtz-Institut Freiberg für Ressourcentechnologie feiert 10-jähriges Bestehen und hat noch viel vor; Acamonta 2021

Jentzsch, A.-K.

Die Entwicklung, die das Helmholtz-Institut Freiberg für Ressourcentechnologie (HIF) seit seiner Gründung genommen hat, ist eine Erfolgsgeschichte. Denn wer hätte vor 10 Jahren gedacht, dass die Idee, ein Institut für Ressourcentechnologie zu gründen, so schnell Früchte tragen würde! Eine wesentliche Rol-
le spielt dabei, dass es ein Helmholtz-Institut geworden ist, denn Institute dieses Namens geben strategischen Partnerschaften zwischen Zentren der Helmholtz-Gemeinschaft und Universitäten eine besondere Intensität. In unserem Fall ist es die dauerhaft enge Zusammenarbeit auf dem Gebiet der Ressourcentechnologie zwischen dem Helmholtz-Zentrum Dresden-Rossendorf (HZDR) und der TU Bergakademie Freiberg. Der Namensgeber der Gemeinschaft, Hermann von Helmholtz, vertrat eine Naturwissenschaft, die Brücken zwischen Medizin, Physik und Chemie schlägt. Seine bahnbrechenden Forschungen und Entwicklungen verknüpften Theorie, Experiment und praktische Anwendung miteinander. Diesen bewährten Ansatz möchte das HIF mit dem Ausbau eines Campus für Ressourcentechnologie und Nachhaltigkeit am Standort Chemnitzer Straße 40 in Freiberg fortschreiben und auch damit ein national sowie international ausgerichtetes Kompetenzzentrum zur Erforschung, Entwicklung und Bewertung innovativer Ressourcentechnologien im Kontext einer dem Nachhaltigkeitsprinzip verpflichteten Kreislaufwirtschaft sein. Mit dem Forschungscampus wird es möglich, Innovationen für den nachhaltigen Umgang mit komplex zusammengesetzten Rohstoffen bzw. Stoffströmen voranzutreiben und die Aufbereitung und Rückgewinnung dieser
Rohstoffe auf hohem wissenschaftlich-technischen Niveau vom Labor- in den Pilotmaßstab zu überführen. Ziel ist es dabei, die entsprechenden Technologieentwicklungen zeitnah in die industrielle Praxis zu bringen. Damit steigt die Attraktivität des Standorts Freiberg nicht nur als Forschungspartner der TU Bergakademie Freiberg, sondern auch hinsichtlich der Zusammenarbeit mit sächsischen, nationalen und internationalen Partnern aus Wissenschaft und Wirtschaft.

Keywords: HIF; 10 Jahre; Ressourcentechnologie; Kreislaufwirtschaft

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 28(2021)1, 25-27

Permalink: https://www.hzdr.de/publications/Publ-37478


Bergbauexploration einmal anders: ein europäisches Projekt, um neue Werte in den Sektor zu bringen; Acamonta 2020

Kirsch, M.; Gloaguen, R.; Ajjabou, L.

Jedes technische Gerät, das in unserer Gesellschaft eingesetzt wird, benötigt Materialien, die entweder aus unserer natürlichen Umwelt („Primärrohstoffe“)
oder aus der Wiederverwendung von Materialien in bestehenden Produkten (Recycling, „Sekundärrohstoffe“) gewonnen werden. Darüber hinaus nimmt die von der Industrie benötigte Materialmenge in dem Maße zu, wie der menschliche Reichtum und die Bevölkerung wachsen. Selbst in einer Kreislaufwirtschaft müssen die Bodenschätze die Sekundärrohstoffe ergänzen und eine grundlegende Basis für unseren materiellen Wohlstand bilden. Natürlich stellen die Gewinnung von Primärrohstoffen, die Notwendigkeit eines effizienteren Recyclings und die Entsorgung von Abfällen, die nicht effizient genutzt oder recycelt werden können, unsere Gesellschaft vor große und komplexe Herausforderungen. Zum Beispiel sind Rohstoffe für die Herstellung
von Batterien, die eine Schlüsseltechnologie für den Energiewandel darstellen, unerlässlich. Während in den kommenden Jahren mit einem exponentiellen Anstieg der Nachfrage nach Batterien gerechnet wird, war die Entwicklung einer wettbewerbsfähigen und lebensfähigen Batterieherstellungsindustrie noch nie so wichtig wie heute, und in ihrem Kern die Versorgung mit sogenannten „kritischen“ Metallen. Auf der anderen Seite steht die starke Nachfrage nach Rohstoffen in unserer postindustriellen Gesellschaft im Gegensatz zu den zunehmenden Schwierigkeiten bei der Suche und Erschließung neuer Mineralvorkommen.

Keywords: Exploration; primäre und sekundäre Rohstoffe; Projekt INFACT; Erkundung

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 27(2020)1, 45-47

Permalink: https://www.hzdr.de/publications/Publ-37477


Eine Renaissance der Freiberger Flotationsforschung – A Fine Future in der Helmholtzgemeinschaft; Acamonta 2019

Rudolph, M.; Eckert, K.

Die Flotation, ein Trennprozess basierend auf der unterschiedlichen Benetzbarkeit von Mikropartikeln und wichtigster Vertreter der Heterokoagulationstrennprozesse, erwuchs seit Ende des 19. Jahrhunderts zu einem der bedeutesten Aufbereitungsprozesse für verschiedenste Erztypen. Es wird sogar davon ausgegangen, dass ohne die Flotation die Versorgung des wachsenden Bedarfs vieler wichtiger Rohstoffe, z. B. Kupfer, gegen Mitte des 20. Jahrhunderts zum Erliegen gekommen wäre. Freiberg war bis zu Zeiten der deutschen Wiedervereinigung ein weltweit führender Standort in der Flotationsforschung sowohl in ihren Grundlagen als auch für die industrielle Anwendung. Mit der Gründung des Helmholtz-Instituts Freiberg für
Ressourcentechnologie (HIF) des Helmholtz-Zentrums Dresden-Rossendorf (HZDR) an der TU Bergakademie Freiberg im Jahr 2011 wurde begonnen, diese Kernkompetenz in Freiberg und Dresden wiederaufzubauen. In diesem Artikel werfen wir einen Blick auf den regional historischen Bezug zum Flotati-
onsprozess und dessen Erforschung, beschreiben den Neuaufbau der Flotationsforschung von 2011 bis heute, stellen das wichtige vom HZDR koordinierte EU-Projekt „FineFuture“ vor und geben einen Einblick in die aktuellen Forschungsakzente im Bereich Flotation.

Keywords: Flotation; Fine Future; Trennprozesse; Aufbereitung

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 26(2019)1, 38-39

Permalink: https://www.hzdr.de/publications/Publ-37476


rECOmine - Regionales Netzwerkprojekt für ressourcenorientierte Umwelttechnologien; Acamonta 2018

Grigoleit, J.; Büttner, P.; Hesse, A.; Peuker, U. A.; Gutzmer, J.

Mit dem regionalen Verbundvorhaben "rECOmine - Ressourcenorientierte Umwelttechnologien für das 21. Jahrhundert" beteiligen sich die TU Bergakademie Freiberg und das Helmholtz-Institut Freibger für Ressourcentechnologie (HIF) gemeinsam mit weiteren Partnern am BMBF-Programm "WIR! - Wandel durch Innovation in der Region". Mit diesem Programm sollen durch die Förderung regionaler themenbezogener Innovationscluster Leuchttürme für den Strukturwandel geschaffen werden, von denen Impulse für die wirtschaftliche Entwicklung ganzer Regionen ausgehen, wobei in der aktuellen Ausschreibung der Fokus vor allem bei den strukturschwachen ländlichen Regionen in Ostdeutschland liegt. Von ursprünglich 105 eingereichten Konzepten wurden 32 Vorhaben mit besonders guten Erfolgsaussichten ausgewählt und aufgefordert, sich mit entsprechend fundierten Innovationskonzepten für eine Förderung im Umfang von bis zu 15 Mio. EUR zu bewerben, darunter auch das Bündnis rECOmine.

Keywords: recomine; Netzwerk; HIF; Freiberg; TU Freiberg; Bündnis; Strukturwandel

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 25(2018)1, 85-87

Permalink: https://www.hzdr.de/publications/Publ-37475


Peptide für die spezifische Interaktion mit Mineralen; Acamonta 2018

Lederer, F.; Braun, R.; Pollmann, K.

Recycling ist eine wichtige Komponente der Kreislaufwirtschaft, um Ressourcen zu schonen. Auch die Biologie wird dazu zukünftig ihren Beitrag leisten. Dabei steht das Recycling von Edelmetallen und Seltenen Erdelementen (SEE), welche in Elektronikprodukten verbaut sind, im Mittelpunkt eines Forschungszweiges der Abteilung Biotechnologie am Helmholtz-Institut Freiberg für Ressourcentechnologie (HIF). Die Wissenschaftler erforschen biologie-basierte Prozesse zum Recycling wirtschaftsstrategischer Metalle aus z. B. Smartphones oder Windturbinen. Ziel der Forschung ist es, Bioreagenzien für Flotationsverfahren – also die Aufbereitung feinster Teilchen – zu entwickeln. Die Phagen, also Viren die Bakterien als Wirtsorganismus nutzen, liefern dabei die erforderliche Materialspezifität und Affinität, um die Metalle selektiv aus einem Materialgemisch abzutrennen und gleichzeitig den bisher notwendigen Einsatz giftiger Trennchemikalien zu reduzieren.

Keywords: Recycling; Biotechnologie; Peptide; Minerale; Seltene Erden

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 25(2018)1, 60-63

Permalink: https://www.hzdr.de/publications/Publ-37474


Neues Wissen zur Metallogenese im Freiberger Revier: 850 Jahre nach dem Silberfund - und (k)ein bisschen klüger?; Acamonta 2018

Burisch-Hassel, M.; Bauer, M. E.; Frenzel, M.; Hartmann, A.; Kehrer, C.; Ostendorf, J.; Seifert, T.; Gutzmer, J.

Im Jahr 2018 feiert die Stadt Freiberg das 850. Jubiläum des ersten Silberfundes im Jahre 1168. Dieses Ereignis gilt als Auslöser für den intensiven Bergbau im Freiberger Distrikt, der von 1168 bis 1969 andauerte. Trotz des langanhaltenden Silberabbaus ist das Ressourcenpotential des Freiberger Distriktes keineswegs erschöpft, da die meisten Bergbaubetriebe aus politischen, technischen oder auch ökonomischen Faktoren eingestellt wurden und nicht etwa deswegen, weil kein Erz mehr vorhanden gewesen sei. Die aktuelle Explorationstätigkeit von Globex Mining Inc. in den nördlichen Randgebieten verdeutlicht dieses Potential (http://www.globexmining.com).
Neben dem Bergbau und der damit verbundenen sozio-ökonomischen Bedeutung für die Region war der Silberbergbau maßgeblicher Grund für die Entstehung und Entwicklung der TU Bergakademie Freiberg (TUBAF) in 1756. Auch die Entstehung der Lagerstättenforschung als wissenschaftliche Fachrichtung ist letztlich eine Konsequenz des ersten Silberfundes. Speziell in Bezug auf die Lagerstättenforschung im Freiberger Distrikt sind Werner (1791), Breithaupt (1849), von Cotta (1850), Müller (1901) und Baumann (1965) zu nennen, wobei von Cotta (1850) das weltweit erste Buch zur Lagerstättenforschung als Fach- und Lehrrichtung verfasste. Ohne die Leistung dieser Vorreiter schmälern zu wollen, sind deren Arbeiten überwiegen beschreibend, was dem damaligen Kenntnisstand und den begrenzten analytischen Möglichkeiten entsprach. Gerade weil viele der Bergwerke heute nicht mehr für die Beprobung zugänglich sind, bilden diese beschreibenden Arbeiten dennoch ein essentielles Fundament des Wissens für moderne Forschungsprojekte. Ziel aktueller Forschungsarbeiten ist es, die geologischen Bildungsbedingungen (Druck, Temperatur, Zusammensetzung der erzbildenden hydrothermalen Lösungen), Bildungsprozesse (Quelle, Transport und Ausfällung) und absoluten Alter der jeweiligen Mineralisationsphasen genauer zu bestimmen. Es sind eben diese Kenntnisse, die dazu dienen, genetische Modelle für den Freiberger Distrikt zu entwickeln. Letztere sind die Grundlage für eine erfolgreiche Neubewertung und Neuerkundung (McCuaig et al., 2010; Occhipinti et al., 2016).
Die Professur für Lagerstättenlehre und Petrologie der TU Bregakademie Freiberg und das Helmholtz-Institut Freiberg für Ressourcentechnologie haben mehrere gemeinsame Forschungsprojekte ins Leben gerufen, die die eklatanten Wissenslücken zur Genese des Freiberger Distrikts schließen wollen. Mit sorgfältig angelegten Studien und modernen Analyseverfahren soll das Verständnis der Entstehung der Freiberger Gänge auf einen aktuellen Forschungsstand gebracht werden. Konkret wird dabei ein starker Fokus auf die Analyse von Flüssigkeitseinschlüssen, Haupt- und Spurenelementanalysen von Erzmineralen und die Altersbestimmung von Erz- und Begleitmineralen (radiogene Isotopenanalysen) gelegt.

Keywords: Freiberg; Bergbau; Lagerstättenforschung; Geologie; Silber

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 25(2018)1, 8-13

Permalink: https://www.hzdr.de/publications/Publ-37473


EIT Raw Materials: Neue Perspektiven für die europäische Rohstoffforschung; Acamonta 2015

Gutzmer, J.; Klossek, A.; Pereira, T.

Obwohl Europa über ein enormes Innovationspotenzial verfügt, entstehen besonders im Rohstoffsektor nur wenige Start-up-Unternehmen. Neuartige Technologien und Prozesse schaffen – trotz exzellenter Forschung – zu selten den Sprung auf den Markt. Zwar stehen den meisten Start-ups in der frühen Entwicklungsphase öffentliche Fördermittel, wie z. B. Gründer-Fonds, zur Verfügung, doch fehlt ihnen danach oft das nötige Geld für den entscheidenden Wachstumsschub hin zu einer kapitalmarktbasierten Eigenfinanzierung. Häufig wird diese Phase als „Tal des Todes“ bezeichnet. Ein Unternehmen, das sie überlebt, erhält Zugang zu einem Markt, der Investoren bereithält, die voraussichtlich tragfähige Geschäftsmodelle im Weiteren unterstützen.
Damit mehr Start-up-Unternehmen zukünftig dieses Tal des Todes überwinden und so das Innovationspotenzial des europäischen Rohstoffsektors auch ausgeschöpft werden kann, wollen 115 europäische Partner – zu denen das zum Helmholtz-Zentrum Dresden-Rossendorf gehörige Helmholtz-Institut Freiberg für Ressourcentechnologie und die TU Bergakademie Freiberg zählen – gemeinsam einen wichtigen Paradigmenwechsel anstoßen. Wettbewerbsfähigkeit, Wachstum und Attraktivität des europäischen Rohstoffsektors sollen durch radikale Innovation, aber auch Unternehmergeist gesteigert werden. Ziel ist es, diesen wichtigen Industriesektor zu einer strategischen Säule der Wirtschaft der EU zu machen. Das Europäische Institut für Innovation und Technologie (EIT) – eine Organisation der EU – teilt diese Vision. Es hat deshalb Anfang Dezember 2014 ein Konsortium, koordiniert vom Helmholtz-Zentrum Dresden-Rossendorf und von der Fraunhofer-Gesellschaft, damit beauftragt, eine Wissens- und Innovationsgemeinschaft (Knowledge and Innovation Community, KIC) für den Rohstoffsektor zu etablieren. Das neue KIC trägt den Namen „EIT Raw Materials“. Es bringt Unternehmen und Forschungseinrichtungen aus 22 EU-Mitgliedsstaaten unter einem Dach zusammen. Damit ist EIT Raw Materials das größte Rohstoffnetzwerk der Welt, das
auf ideale Weise ein für alle KIC charakteristisches Wissensdreieck aus Ausbildung, Forschung und Industrie erzeugt. Durch seine enorme Anzahl von Partnern verfügt das Netzwerk über Kompetenzen aus dem gesamten Spektrum des Wissens und Forschens über die mineralischen und metallhaltigen Rohstoffe und deckt alle Glieder der Rohstoff-Wertschöpfungskette vollständig ab – von der Erkundung über die Aufbereitung bis hin zu Recycling und
der Substitution von Ressourcen. Diesen strategischen Vorteil will das Institut dazu nutzen, um Barrieren, die die Zusammenarbeit zwischen Hochschulen, Forschungseinrichtungen und Unternehmen behindern, zu überwinden. Auf diese Weise soll der Dialog zwischen den involvierten Potenzialen und Bereichen vor allem durch Verständigung über jeweils anzugehende Ziele sowie durch den Austausch von Ideen und Forschungsergebnissen vereinfacht werden. Nur so kann sich der europäische Rohstoffsektor und können sich auch die an ihn angrenzenden Branchen in einen Wachstumsmarkt für
Investitionen, Innovationen und talentierte Entrepreneure verwandeln. Damit dies gelingt, müssen sich Politiker, Unternehmer und Wissenschaftler
darüber im Klaren sein, welche Herausforderungen der europäische Rohstoffsektor zu bewältigen hat. Denn im Vergleich zu Ländern wie China, Russland oder den USA ist die EU bei der Versorgung mit existenziell wichtigen mineralischen und metallischen Rohstoffen noch deutlich stärker vom globalen Handel abhängig. Eine der wichtigsten Aufgaben des EIT Raw Materials wird es deshalb sein, neue ökonomisch und ökologisch fundierte Konzepte
zu entwickeln: für die Nutzung heimischer Lagerstätten, den Bergbau unter schwierigen, oft urbanen Bedingungen – ebenso wie für den Ausbau einer wettbewerbsfähigen rohstoffverarbeitenden und sonstigen rohstoffnahen Industrie. Eine weitere Herausforderung wird sein, mit neuen Technologien und Nutzungskonzepten den Weg für eine effiziente und nachhaltige Kreislaufwirtschaft zu ebnen. Ausgediente Hightech-Produkte etwa, wie Smartphones oder Laptops, dürfen nicht mehr als Müll angesehen werden, sondern vielmehr als Quelle für die Rückgewinnung wertvoller Rohstoffe.
Um diese und weitere Aufgaben meistern zu können, gilt es, alle Partner des KIC optimal miteinander zu verknüpfen. In lokalen Zentren, den sog. Co-Location Centers (CLC), bündelt das Netzwerk dafür transnationale Regionen mit thematischen Schwerpunkten. Insgesamt gibt es sechs solcher Zentren, und zwar in Italien, Frankreich, Polen, Belgien, Finnland und Schweden. Das EIT Raw Materials koordiniert sie von seinem Hauptsitz in Berlin aus. Die deutschen Partner beteiligen sich an den drei CLC in Frankreich, Belgien und Polen.

Keywords: EIT; Raw Materials; KIC; Freiberg; TU Freiberg; EU; Rohstoffforschung; Netzwerk

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 22(2015)1, 91-93

Permalink: https://www.hzdr.de/publications/Publ-37472


Hochtechnologiemetalle als industrielle Beiprodukte - Bedeutung von Geometallurgie und Rohstoffcharakterisierung; Acamonta 2015

Frenzel, M.; Krause, J.; Bachmann, K.; Gutzmer, J.

Indium, ein silberfarbenes, weiches, dem Zinn sehr ähnliches Metall, hat eine ganz besondere Beziehung zu Freiberg: nicht nur, dass es im Jahr 1863 von Reich und Richter an der Bergakademie entdeckt wurde; auch das für die Arbeit der beiden Entdecker verwendete Probenmaterial entstammte dem lokalen
Bergbau. Heutzutage kommt Indium große Bedeutung als einem der wichtigsten Hochtechnologiemetalle zu, ohne das der weltweit verbreitete Einsatz von Smartphones und Flachbildschirmen nicht möglich wäre. Gewonnen wird es hauptsächlich als Beiprodukt aus Zinkund untergeordnet auch aus Kupfererzen. D. h. es gibt keine Indiumbergwerke, sondern Indium wird bei der Verhüttung der Erze dieser beiden Hauptmetalle gewonnen. Da aber der Wert des in den Erzen enthaltenen Indiums oft sehr viel geringer ist als der der Hauptmetalle (< 10 %), hat seine Konzentration keinen Einfluss darauf, welche Erze abgebaut werden. Das führt dazu, dass die weltweit zur industriellen Verfügung stehende Menge an Indium letztendlich durch den Umfang der (Kupfer- und) Zinkproduktion begrenzt ist. Diese Limitation erzeugt ein großes pozenzielles Versorgungsrisiko. Indium ist damit ein typisches Beispiel eines Hochtechnologiemetalls, das ausschließlich als Beiprodukt gewonnen werden kann.
Am Beispiel der polymetallischen Lagerstätte Neves-Corvo in Portugal soll in diesem Beitrag dargestellt werden, welche Informationen zur Verfügung stehen müssen, um die Nutzung von Beiprodukten – wie eben von Indium – zu ermöglichen. Die Lagerstätte Neves-Corvo beherbergt mit einem zzt. noch verbliebenen Gesamtinhalt von > 1.000 t Indium die größte bekannte Konzentration dieses Elements in einer abbauwürdigen Lagerstätte in Europa. Jedoch profitiert das Unternehmen Somincor, das die Lagerstätte Neves-Corvo abbaut, momentan nicht von diesem Reichtum: Die in Neves-Corvo produzierten Cu- und Zn-Konzentrate erreichen in der Regel nicht die von den Hütten für die Vergütung verlangten Indium-Mindestgehalte. Ziel der in diesem Artikel beschriebenen Arbeit ist es, auf geometallurgischen Untersuchungen aufbauend Nutzungskonzepte zu entwickeln, die dem Unternehmen bei der vollen
Ausschöpfung seines Indiumpotenzials helfen können. Die dazu durchgeführte Studie ist – unseres Wissens – die weltweit erste ausführliche geometallurgische Studie zur Konzentrationsverteilung und Gewinnbarkeit von Indium als Beiprodukt. Da diese Studie noch nicht abgeschlossen ist, werden im Folgenden nur vorläufige Ergebnisse präsentiert.

Keywords: Geometallurgie; Indium; Rohstoffe; Bergbau; Metalle; Lagerstätte Neves-Corvo

  • Acamonta - Zeitschrift für Freunde und Förderer der Technischen Universität Bergakademie Freiberg 22(2015)1, 25-28

Permalink: https://www.hzdr.de/publications/Publ-37471


Beschleunigungsmessung als Grundlage für die Strömungsverfolgung in Bioreaktoren mit Sensorpartikeln

Buntkiel, L.; Reinecke, S.; Hampel, U.

The triaxial measurement of accelerations using sensor particles in bioreactors is essential for flow analysis. Due to the mechanical structure of the sensor particles, the accelerometer is not located in the center of the applied forces. Therefore, centrifugal and Euler acceleration superposes its measurements. Due to the high dynamics and, the high angular velocities that the sensor particle experiences in the reactor, this influence cannot be neglected despite the small size of the sensor particles and must be taken into account in the system mode

Keywords: Flow measurement; Flow follower; Bioreactor

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Permalink: https://www.hzdr.de/publications/Publ-37470


Giant THz nonlinearity in topological and trivial HgTe-based heterostructures: Data

Uaman Svetikova, T. A.; de Oliveira, T.; Pashkin, A.; Ponomaryov, A.; Berger, C.; Fuerst, L.; Bayer, F.; Novik, E.; Buhmann, H.; Molenkamp, L.; Helm, M.; Kiessling, T.; Winnerl, S.; Kovalev, S.; Astakhov, G.

This upload represents the data used for publication <<Giant THz nonlinearity in topological and trivial HgTe-based heterostructures>> including datasets, images and programming code.

1. Raw_data.rar contains raw data files obtained during transport measurements, two-colour pump-probe experiments(FELBE) and third harmonic generation experiments.

2. Drude_fit.rar contains the result of fitting the complex change in conductivity with Drude fit.

3. Band_structure_calculation.rar contains the result of the fermi energy and dispersion calculations based on kp-method.

4. Theoretical_model_calculation.rar contains the code of the program for the theoretical model for THG and fitting it with experimental data and its result

5. Presentation_Sample_QC0600.pptx contains the information about used sample.

Keywords: topological insulators; third harmonic generation; HgTe

Involved research facilities

  • T-ELBE
  • F-ELBE

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Permalink: https://www.hzdr.de/publications/Publ-37468


Leveraging Ligand and Composition Effects: Morphology-Tailorable Pt–Bi Bimetallic Aerogels for Enhanced (Photo-)Electrocatalysis

Xue, G.; Li, Y.; Du, R.; Wang, J.; Hübner, R.; Gao, M.; Hu, Y.

Metal aerogels (MAs) are emerging porous materials displaying unprecedented potential in catalysis, sensing, plasmonic technologies, etc. However, the lack of efficient regulation of their nano-building blocks (NBBs) remains a big hurdle that hampers the in-depth investigation and performance enhancement. Here, by harmonizing composition and ligand effects, Pt- and Bi-based single- and bimetallic aerogels bearing NBBs of controlled dimensions and shapes are obtained by facilely tuning the metal precursors and the applied ligands. Particularly, by further modulating the electronic and optic properties of the aerogels via adjusting the content of the catalytically active Pt component and the semiconducting Bi component, both the electrocatalytic and photoelectrocatalytic performance of the Pt–Bi aerogels can be manipulated. In this light, an impressive catalytic performance for electro-oxidation of methanol is acquired, marking a mass activity of 6.4-fold higher under UV irradiation than that for commercial Pt/C. This study not only sheds light on in situ manipulating NBBs of MAs, but also puts forward guidelines for crafting high-performance MAs-based electrocatalysts and photoelectrocatalysts toward energy-related electrochemical processes.

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-37466


Radiolabeling of Micro-/Nanoplastics via In-Diffusion

Stricker, A.; Hilpmann, S.; Mansel, A.; Franke, K.; Schymura, S.

Micro- and nanoplastics are emerging pollutants with a concerning persistence in the
environment. Research into their environmental impact requires addressing challenges related to
sensitively and selectively detecting them in complex ecological media. One solution with great
potential for alleviating these issues is using radiolabeling strategies. Here, we report the successful
introduction of a 64Cu radiotracer into common microplastics, namely polyethylene, polyethylene
terephthalate, polystyrene, polyamide, and polyvinylidene dichloride, which allows the sensitive
detection of mere nanograms of substance. Utilizing a Hansen Solubility Parameter screening, we
developed a swelling and in-diffusion process for tetraphenylporphyrin-complexed 64Cu, which
permits one-pot labeling of polymer particles

Keywords: microplastics; radiolabeling; Hansen solubility parameters; In-Diffusion

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Permalink: https://www.hzdr.de/publications/Publ-37465


Nanomagnetism and strain effects in magnetoelectric antiferromagnet Cr2O3

Pylypovskyi, O.

Concepts of the future of spintronics are often based on antiferromagnetic materials because of their attraction for low-energy operating and high-speed devices. However, an absence of significant net magnetization also results in challenges for manipulation and readout of the magnetic state. In this respect, room-temperature magnetoelectric easy-axis Cr2O3 is of special interest [1].

In a single-crystal Cr2O3 domain wall is a metastable excitation, which can be induced by a magnetoelectric poling procedure and being pinned by specially designed surface defects. In contrast, thin films usually have a granular structure with significant amount of crystal defects acting as pinning sites for domain walls. Concentration and structure of the defects can be controlled by the film fabrication procedure, keeping the net magnetoelectric effect present for the sample [2]. Furthermore, low-defect films grown at sapphire can be persistently strained [3]. An out-of-plane magnetic moment formed by one of antiferromagnetic sublattices at the c-plane of Cr2O3 provides a possibility for the Hall magnetometry detecting magnetization direction by the Hall resistance measured in Pt capping layer [4].

The Neel temperature of bulk Cr2O3 of 35C is the strong limiting technological factor for practical applications. There are theoretical and experimental demonstrations that the compressive strain induced by doping or procedure of growing at sapphire substrate leads to the substantial broadening of the antiferromagnetic phase by temperature increasing the Neel temperature above 100C [3,5]. Furthermore, strained thin films can possess an inhomogeneous strain along the thickness, enabling net magnetization of flexomagnetic origin and vertical gradient of the Neel temperature. The latter provides a local flexomagnetic response which is controlled by the direction of the antiferromagnetic order parameter and scales with the sample’s temperature [3].

We anticipate that Cr2O3 provides a flexible material platform for the fundamental and applied physics by demonstration of unique crystal-symmetry-assisted effects.

Keywords: Cr2O3; magnetoelectricity; flexoeffects

  • Invited lecture (Conferences)
    IEEE NAP 2023, 10.-15.09.2023, Bratislava, Solvakia

Permalink: https://www.hzdr.de/publications/Publ-37464


Analysis of the influence of swirling flow on the boiling heat transfer characteristics of two-phase flow

Wu, W.; Ding, W.; Hampel, U.; Sun, B.

The Eulerian-Eulerian (EE) simulation approach + GENeralized TwO Phase (GENTOP) concept and two-fluid three-flow field with droplet were used to simulate the heat and mass transfer. Analysis encompassed the examination of steam and liquid phase distributions, as well as flow pattern transitions. Heat transfer enhancements were quantified using a comprehensive heat transfer factor. The disturbance intensity of the secondary flow was characterized by the absolute vortex flux. Results revealed a correlation between the intensity of the secondary flow and axial length, indicative of progressive fluid disturbance enhancement. Additionally, the maximal motion of the steam phase vortex was observed both near the wall and channel center. The EE+GENTOP concept exhibited superior capability in reproducing multi-scale flow including small-scale dispersed bubbles and large-scale continuous steam (coalescence and break-up). For investigations into the entrainment and deposition of liquid droplets in annular flow, the selection of a two-fluid three-flow field with the droplet model is recommended.

Keywords: swirling flow; secondary flow; heat transfer enhancement; two-phase flow

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  • Secondary publication expected from 16.12.2024

Permalink: https://www.hzdr.de/publications/Publ-37463


Coordination chemistry of the early actinides in various oxidation states (+III to +V) with benzamidinate ligand

Hong, B.; Kaden, P.; Näder, A.; Gericke, R.; Patzschke, M.; Schmidt, M.; Stumpf, T.; März, J.

Compared to the lanthanides, which primarily exhibit the oxidation state +III, the early actinides up to plutonium can display a diverse range of oxidation states spanning from +I to +VII. In the context of exploring oxidation states and covalency of actinides complexes, it would be intriguing and valuable to compare compounds that share the same molecular scaffold but differ in their oxidation states. Amidinate ligands have been widely studied in the field of coordination chemistry due to their excellent capability to stabilize transition metal complexes in various oxidation states, including some early actinide metal complexes. Thus, N,N'-diisopropylbenzamidinate (iPr2BA) was selected as an appropriate model N-donor ligand for the current study. Our goal was to test the ligand’s ability to stabilize actinides in various oxidation states as well as its synthetic flexibility.
In order to gain insight into the bonding trends and electronic structures of each oxidation state, series of tetravalent actinide tris-iPr2BA chloride complexes [AnIVCl(iPr2BA)3] (An = Th, U, Np) were synthesized via salt metathesis, followed by subsequent synthetic transformations to obtain (pseudo)halide congeners and complexes in the +III and +V oxidation states. The synthesized complexes were analyzed by single crystal X-ray diffraction (SC-XRD) to examine their molecular structures in solid state. Furthermore, the combination of paramagnetic NMR experiments in solution and quantum chemical calculations enabled the comparison of the overall degree of covalency between different oxidation states within the same tris-amidinate complex scaffold.

Keywords: Actinides; Lanthanides; Coordination chemistry; SC-XRD; NMR; amidinate; N-donor ligands; paramagnetism

  • Lecture (Conference)
    The 11th International Conference on f Elements (ICFE-11), 22.-26.08.2023, Strasbourg, France

Permalink: https://www.hzdr.de/publications/Publ-37462


A direct numerical simulation study to elucidate the enhancement of heat transfer for nucleate boiling on surfaces with micro-pillars

Zhang, J.; Rafique, M.; Ding, W.; Bolotnov, I. A.; Hampel, U.

Recent experimental studies have demonstrated great potential of surface engineering in enhancing nucleate boiling heat transfer performance. However, the underlying mechanism remains unclear, especially the role of microlayer evaporation underneath bubbles. In this work, we investigate the heat transfer from microlayer evaporation underneath a growing bubble on micro-pillar arrayed surfaces using Direct Numerical Simulations (DNS). The evolution of the microlayer is reproduced in the DNS by considering a bubble growth driven by the local temperature gradient. The effects of micro-pillar structures on the microlayer profile and the heat transfer performance are systematically studied and analyzed. Our simulation results reveal three distinct microlayer morphologies related to micro-pillar structures: the undisturbed microlayer, the disturbed microlayer, and the disrupted microlayer. It can be further generalized as the greater the spacing and height of the micro-pillars, the more disrupted the microlayer becomes. Due to the reduction of microlayer thickness, more disruption means higher microlayer heat transfer coefficient. However, this accelerates microlayer depletion and thus reduces the overall heat transfer potential from microlayer evaporation during its life cycle in nucleate boiling. Based on these findings, a strategy is revealed for the design of micro-pillar arrayed surfaces to achieve optimal heat transfer performance of the microlayer.

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  • Secondary publication expected from 26.07.2024

Permalink: https://www.hzdr.de/publications/Publ-37461


Bispidine Chelators for Radiopharmaceutical Applications with Lanthanide, Actinide and Main Group Metal Ions

Kopp, I.; Cieslik, P.; Anger, K.; Josephy, T.; Neupert, L.; Velmurugan, G.; Gast, M.; Wadepohl, H.; Brühlmann, S. A.; Walther, M.; Kopka, K.; Bachmann, M.; Stephan, H.; Kubeil, M.; Comba, P.

Octa- and specifically nonadentate ligands with a bispidine scaffold (3,7-diazabicyclo[3.3.1]nonane) are known to be efficiently coordinated to a range of metal ions of
interest in radiopharmaceutical chemistry and lead to exceedingly stable and inert complexes. The nonadentate bispidine L2 (with a tridentate bipyridine acetate appended to N3 and a
picolinate at N7) has been shown before to be an ideal chelator for 111In3+, 177Lu3+ and 225Ac3+, nuclides of interest for diagnosis and therapy, and a proof-of-principle study with an SSTR2-specific octreotate has shown potential for theranostic applications. We now have extended these studies in two directions. Firstly, we present the ligand derivative L3, where the bipyridine acetate is substituted with terpyridine, a softer donor for metal ions with a preference for more covalency. L3 did not fulfill the hopes because complexation is much less efficient: while for Bi3+ and Pb2+ the ligand is an excellent chelator with similar properties to L2, Lu3+ and La3+ show very slow and inefficient complexation with L3 in contrast to L2, and 225Ac3+ is not fully coordinated, even at an elevated temperature (92% radiochemical yield (RCY) at 80 °C, 60 min, [L3] = 10-4 M). These observations have led to a hypothesis for the complexation pathway that is in line with all experimental data and supported by a preliminary DFT analysis, which is of importance for the design of further optimized bispidine chelators. Secondly, the coordination chemistry of L2 has been extended to Bi3+, La3+ and Pb2+, including solid state and solution structural work, complex stabilities, radiolabeling and radiostability studies. All complexes of this ligand (La3+, Ac3+, Lu3+, Bi3+, In3+, Pb2+), including nuclides for targeted alpha therapy (TAT), single photon emission computed tomography (SPECT), and positron emission tomography (PET) are formed efficiently at physiological conditions, i.e., suitable for the labeling of delicate biological vectors such as antibodies, and the complexes are very stable and inert. Importantly, for TAT with 225Ac, the daughter nuclides 213Bi and 209Pb also form stable complexes, and this is of importance to reduce damage to healthy tissue.

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Permalink: https://www.hzdr.de/publications/Publ-37460


Richtungsaufgelöste Messung von Beschleunigungen mit Sensorpartikeln in industriellen Prozessbehältern

Buntkiel, L.; Reinecke, S.; Hampel, U.

Prozesse wie sie in großen Behältern, etwa in Biogasfermentern, Biorektoren oder Belebtschlammbecken ablaufen, haben ein hohes Optimierungspotenzial hinsichtlich der Energieeffizienz der Vermischung. Schlechtes Mischen im Behälter führt zu zu Totzonen und einer ineffizienten Nutzung der eingetragenen Energie. Messungen in diesen Behältern sind aufgrund des opaken Fluids und der Größe und Beschaffenheit der Behälter mit konventioneller Messtechnik nur an lokalen Messstellen möglich. Um ortsaufgelöst Prozessparameter und die Strömung zu messen, wurde am HZDR das Konzept instrumentierter, strömungsfolgender Sensorpartikel entwickelt. Strömungsfolgende Sensoren werden derzeit von einigen Gruppen weltweit entwickelt. Ausgestattet sind sie mit mindestens einem Druck– und einem Temperatursensor. Auswerteschwerpunkt ist die vertikale Position (Tauchtiefe) im Behälter basierend auf einer Messung des hydrostatischen Drucks. Analysiert werden typischerweise vertikale Aufenthaltswahrscheinlichkeiten, vertikale Geschwindigkeitsprofile, Zirkulationszeiten, aus denen ein Zusammenhang mit der globalen Mischzeit des Reaktors hergestellt wird, sowie ein automatisiertes Einteilen des Behälters in vertikale Mischbereiche als neueste Analysemethode.

Keywords: Sensorpartikel; Strömungsmessung; Kalman-Filter; Sensorfusion; Inertiale Navigation

  • Open Access Logo Contribution to proceedings
    16. Dresdner Sensor-Symposium 2022, 05.-07.12.2022, Dresden, Deutschland, Wunstorf: AMA Service GmbH, 978-3-9819376-7-1, 51-56
    DOI: 10.5162/16dss2022/6.3

Permalink: https://www.hzdr.de/publications/Publ-37458


Oxygen vacancy clusters in bulk cerium oxide and the impact of gold atoms

Longo, A.; Mirone, A.; de Clermont Gallerande, E.; Sahle, C. J.; Casaletto, M. P.; Amidani, L.; Theofanidis, S.; Giannici, F.

We demonstrate the formation of oxygen vacancy clusters in the bulk of ceria and Au/ceria catalysts upon reduction with CO, and their interplay with 4f and 5d orbital hybridization of Ce3+, through state-of-the-art in situ synchrotron characterization and ab initio simulations. In situ X-ray Raman spectroscopy (XRS) at the oxygen K- and cerium N4,5-edges, coupled with in situ X-ray diffraction (XRD), are explained by ab initio density functional theory (DFT) and multiplet calculations. In particular, XRS at cerium N4,5-edges is analyzed here for the first time, unvealing new details on the formation of Ce3+ in the bulk, a key feature of XRS. The combined multiplet analysis at the N4,5-edge allows to detect the formation of Ce3+ also in Au/ceria upon treatment at low temperature. Since bulk sensitivity is a key feature of XRS, the modifications registered at the O K-edge reflect the rearrangement of the oxygen sublattice. DFT calculations are used to simulate the effects of vacancy ordering in the bulk, and allow us to fully explain the modification of the O K-edge involving the hybridization of the Ce 4f and 5d states. According to simulations, these changes can be connected to the oxygen vacancy clustering in the bulk of ceria.

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Room-temperature extended short-wave infrared GeSn photodetectors realized by ion beam techniques

Wen, S.; Shaikh, M. S.; Steuer, O.; Prucnal, S.; Grenzer, J.; Hübner, R.; Turek, M.; Pyszniak, K.; Reiter, S.; Fischer, I. A.; Georgiev, Y.; Helm, M.; Wu, S.; Luo, J.-W.; Zhou, S.; Berencen, Y.

GeSn alloys hold great promise as high-performance, low-cost, near- and short-wavelength infrared photodetectors with the potential to replace the relatively expensive and currently market-dominant InGaAs- and InSb-based photodetectors. In this Letter, we demonstrate room-temperature GeSn pn photodetectors fabricated by a complementary metal-oxide-semiconductor compatible process, involving Sn and P ion implantation and flash-lamp annealing prior to device fabrication. The fabrication process enables the alloying of Ge with Sn at concentrations up to 4.5% while maintaining the high-quality single-crystalline structure of the material. This allows us to create Ge0.955Sn0.045 pn photodetec-tors with a low dark current density of 12.8 mA/cm2 and a relatively high extended responsivity of 0.56 A/W at 1.71 l m. These results pave the way for the implementation of a cost-effective, scalable, and CMOS-compatible short-wavelength infrared detector technology.

Keywords: Semiconductors; Photodetectors; GeSn; Implantation; Flash-lamp annealing

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Permalink: https://www.hzdr.de/publications/Publ-37456


Study of QED singular properties for variable gyromagnetic ratio g≃2

Rafelski, J.; Evans, S.; Labun, L.

Using the external field method, {\it i.e.\/} evaluating the effective action $V_{\mathrm{eff}}$ for an arbitrarily strong constant and homogeneous field, we explore nonperturbative properties of QED allowing arbitrary gyromagnetic ratio $g$. We find a cusp at $g = 2$ in: a) The QED $b_0$-renormalization group coefficient, and in the infinite wavelength limit in b) a subclass containing the pseudoscalar ${\cal P}^{2n}= (\vec E\cdot\vec B)^{2n} $ of light-light scattering coefficients. Properties of $b_0$ imply for certain domains of $g$ asymptotic freedom in an Abelian theory.

Keywords: Schwinger effect; vacuum stability; magnetic moment

Permalink: https://www.hzdr.de/publications/Publ-37455


Axion search via Coulomb-assisted quantum vacuum birefringence

Evans, S.; Schützhold, R.

We study the impact of axions or axion-like particles on birefringent (i.e., polarization changing) scattering of x-ray photons at the Coulomb field of nuclei superimposed by optical lasers of ultra-high intensity. Applying the specifications of the Helmholtz International Beamline for Extreme Fields (HIBEF), we find that this set-up can be more sensitive than previous experiments such as PVLAS in a large domain of parameter space. Furthermore, by changing the pump and probe laser orientations and frequencies, one can scan different axion masses.

Permalink: https://www.hzdr.de/publications/Publ-37454


Improving Euler-Heisenberg-Schwinger Effective Action with Dressed Photons

Evans, S.; Rafelski, J.

We implement a longstanding proposal by Weisskopf to apply virtual polarization corrections to
the in/out external fields in study of the Euler-Heisenberg-Schwinger effective action. Our approach
requires distinguishing the electromagnetic and polarization fields based on mathematical tools
developed by Bia lynicki-Birula, originally for the Born-Infeld action. Our solution is expressed
as a differential equation where the one-loop effective action serves as input. As a first result of
our approach, we recover the higher-order one-cut reducible loop diagrams discovered by Gies and
Karbstein.

Keywords: Euler–Heisenberg–Schwinger (EHS); non-perturbative vac-uum structure; quantum electrodynamics (QED)

Permalink: https://www.hzdr.de/publications/Publ-37453


Lane formation of colloidal particles driven in parallel by gravity

Isele, M.; Hofmann, K.; Erbe, A.; Leiderer, P.; Nielaba, P.

We investigate the lane formation in nonequilibrium systems of colloidal particles moving in
parallel that are driven by the force of gravity. For this setup, an experimental implementation of a channel on a slope can be conceptualized. We employ the Brownian dynamics algorithm and confine the repulsive particles with hard walls based on the solution of the Smoluchowski equation in the half space. A difference of the driving force acting on the colloids could be achieved by using two spherical particle types with differing diameters but equal mass density. Firstly, we investigate how a difference in the channel slope affects the lane formation of the systems, after which we analyze the lanes that formed. We found that the large particles push the small particles to the walls, resulting in exclusively small particle lanes at the walls. This contrasts the equilibrium state, where depletion forces push the larger particles to the walls. Additionally, we have a closer look at the mechanisms by which the lanes form. Finally, we found system parameter values that foster lane formation to lay the foundation for an experimental realization of our proposed setup. To round this off, we give an exemplary calculation of the slope angle needed to get the experimental system into a state of lane order. With the examination of lane order in systems that are driven in parallel, we hope to deepen our understanding of nonequilibrium order phenomena.

Keywords: soft matter; colloidal model systems

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Permalink: https://www.hzdr.de/publications/Publ-37452


Giant THz nonlinearity in topological and trivial HgTe-based heterostructures

Uaman Svetikova, T. A.; de Oliveira, T.; Pashkin, A.; Ponomaryov, O.; Berger, C.; Fuerst, L.; Bayer, F.; Novik, E.; Buhmann, H.; Molenkamp, L.; Helm, M.; Kiessling, T.; Winnerl, S.; Kovalev, S.; Astakhov, G.

Nonlinear phenomena in the THz spectral domain are important for the understanding of optoelectronic properties of quantum systems and provide a basis for modern information technologies. Here, we report a giant THz nonlinearity in high-mobility 2D topological insulators based on HgTe quantum wells, which manifests itself in a highly efficient third harmonic generation. We observe a third harmonic THz susceptibility several times higher than in bare graphene and many orders of magnitude higher than in trivial quantum well structures based on other materials. To explain the strong nonlinearity of HgTe-based heterostructures at the THz frequencies, we consider the acceleration of free carriers with high mobility and variable dispersion. This acceleration model, for which the non-parabolicity of the band dispersion is key, in combination with independently measured scattering time and conductivity is in good agreement with our experimental data in a wide temperature range for THz fields below the saturation. Our approach provides a route to material engineering for THz applications based on frequency conversion.

Keywords: topological insulators; HgTe; third harmonic generation

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Permalink: https://www.hzdr.de/publications/Publ-37451


Helmholtz Open Science Forum “Research Evaluation, Reputation Systems, and Openness”

Genderjahn, S.; Bertelmann, R.; Ferguson, L. M.; Graf Zu Castell-Rüdenhausen, W.; Dransch, D.; Juckeland, G.; Kiesselbach, M.; Köhler, M.; Rank, S.; Rohmann, J. L.; Upmeier, A.; Wiesenfeldt, S.

On May 9, 2023, the Helmholtz Open Science Office organized the Forum "Research Evaluation, Reputation Systems, and Openness". On this occasion, experts from Helmholtz and the scientific community presented current developments in the field of research evaluation and reflected on the connection between reputation systems and openness. The event focused on three main topics: 1) Development of Helmholtz quality indicators for data and software products, 2) 10 years Declaration on Research Assessment (DORA) and 3) Coalition for Advancing Research Assessment (CoARA). A central subject in the discussion and presentations was the issue of the use and definitions of indicators which foster Open Science. The discussion centered on what appropriate incentives look like in order to make research evaluation fair and appreciative. Furthermore, the relevance of these questions from the perspective of early-career scientists was highlighted.

Permalink: https://www.hzdr.de/publications/Publ-37450


Longitudinal cerebral perfusion in presymptomatic genetic frontotemporal dementia: GENFI results

Pasternak, M.; Mirza, S.; Luciw, N.; Mutsaerts, H.; Petr, J.; Thomas, D.; Cash, D.; Bocchetta, M.; Tartaglia, C.; Mitchell, S.; Black, S.; Freedman, M.; Tang-Wai, D.; Rogaeva, E.; Russell, L.; Bouzigues, A.; van Swieten, J.; Jiskoot, L.; Seelaar, H.; Laforce Jr., R.; Tiraboschi, P.; Borroni, B.; Galimberti, D.; Rowe, J.; Graff, C.; Finger, E.; Sandro, S.; de Mendonça, A.; Butler, C.; Gerhard, A.; Sánchez-Valle, R.; Moreno, F.; Synofzik, M.; Vandenberghe, R.; Ducharme, S.; Levin, J.; Otto, M.; Santana, I.; Strafella, A.; Macintosh, B.; Rohrer, J.; Masellis, M.

Genetic frontotemporal dementia is most commonly attributable to mutations in the C9orf72, GRN, or MAPT genes. The disease has near-complete penetrance, making presymptomatic carriers an ideal population for ascertaining the earliest changes in disease progression and the identification of suitable biomarkers for designing therapeutic trials when minimal neuronal loss has occurred. Cerebral perfusion, as measured by arterial spin labelling (ASL) MRI, has shown promise in being one such biomarker. However, longitudinal profiles of change in perfusion over time in presymptomatic carriers across all three genetic subgroups are lacking.
Using data from the multicenter GENetic Frontotemporal dementia Initiative, we investigated longitudinal profiles of cerebral perfusion using ASL-MRI in C9orf72 (n = 42), GRN (n = 70), and MAPT (n = 31) presymptomatic mutation carriers and non-carrier controls (n = 158). ASL and T1w scans were processed with the ExploreASL pipeline to produce partial volume corrected perfusion images, which were parcellated to extract mean perfusion values from whole brain grey matter and regions defined by the second version of the automated anatomical atlas (AAL2). Linear mixed effects models were used to assess longitudinal perfusion change.
Mutation carrier groups and non-carriers were statistically indistinguishable by baseline demographic and clinical measures. Decline in whole brain grey matter perfusion over time was more pronounced in all three carrier subgroups relative to controls, with changes most pronounced in GRN, followed by C9orf72 and MAPT variants. Additionally, GRN and MAPT groups featured global grey matter hypoperfusion relative to non-carrier controls as early as one year after baseline measurement, with C9orf72 featuring significant hypoperfusion after two years. Region of interest analysis demonstrated that each genetic subgroup had its own regional profile in terms of longitudinal perfusion decline. Perfusion decline in C9orf72 was localized around the frontal lobe and subcortical structures with a slight right-hemispheric bias. GRN featured a more widespread perfusion decline, with notable asymmetry featuring a stronger left hemisphere involvement. Significant decline in perfusion in MAPT was limited to the thalamus, which was a region that was significant in all three mutation carrier groups. Cerebral blood flow relative to baseline measurements had declined to a greater extent in converter individuals versus presymptomatic carriers who were past their expected year of disease onset within specific frontal regions of the brain.
These results provide additional evidence that cerebral perfusion is a potential biomarker for assessment of genetic FTD and its genetic subgroups at the prodromal stage of the disease.

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  • PET-Center

Permalink: https://www.hzdr.de/publications/Publ-37449


Hydrodynamics in a Bubble Column – Part 1: Two-Phase Flow

Sommer, A.-E.; Draw, M.; Wang, L.; Schmidtpeter, J.; Hessenkemper, H.; Gatter, J.; Nam, H.; Eckert, K.; Rzehak, R.

Multiphase computational fluid dynamics (CFD) simulation is a useful tool to study the hydrodynamics in a bubble column if
appropriate closure models are known. Systematic assessment of different models is an ongoing venture that benefits from
improved validation data. The present study accumulates a database on two-phase flow experiments in a bubble column.
This is achieved by using a combination of particle image velocimetry and shadowgraphy to measure the liquid velocity field
and gas dispersion properties simultaneously. This methodology is applied for different needle diameters and gas flow rates.
The experimental data are compared with CFD simulations which show good predictions. A systematic investigation of the
three-phase flow in the bubble column will appear as a sequel.

Keywords: Closure relations; Euler-Euler two-fluid model; Particle image velocimetry; Shadowgraphy; Two-phase bubble column

Permalink: https://www.hzdr.de/publications/Publ-37448


Data publication: Exploring Hydrophilic PD-L1 Radiotracers Utilizing Phosphonic Acids: Insights Into Unforeseen Pharmacokinetics

Krutzek, F.; Donat, C.; Stadlbauer, S.

Bei diesem Datensatz handelt es sich um die chemische Charakterisierung der Verbindungen, die in-vitro- und in-vivo-Daten.

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  • PET-Center

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Permalink: https://www.hzdr.de/publications/Publ-37447


Exploring Hydrophilic PD-L1 Radiotracers Utilizing Phosphonic Acids: Insights Into Unforeseen Pharmacokinetics

Krutzek, F.; Donat, C.; Stadlbauer, S.

Immune checkpoint inhibitor therapy targeting the PD-1/PD-L1 axis in cancer patients holds promise as an oncological treatment. However, the number of non-responders remains high. Consequently, clinicians need a diagnostic tool to predict treatment outcomes. PET imaging can play an important role in supporting therapy decisions by offering whole-body scan while quantitatively assessing PD-L1 expression. In multi-step organic synthesis, four PD-L1 radiolig-ands containing a linker-chelator system for radiometallation, along with three hydrophilizing units – one sulfonic acid and two phosphonic acids – were synthesized. After labeling with 64Cu, log D7.4 values of below –3.03 were determined and proteolytic stability studies were conducted confirming stabilities over 94% after 48 hours. Binding affinities studies were conducted using two different binding assays revealing high affinities up 13 nM. µPET/CT imaging was performed in tumor-bearing mice to investigate PD-L1 specific tumor uptake and the pharmacokinetic profile. The µPET images revealed an unexpected in vivo behavior, including low tumor uptake in PD-L1 positive tumors, high liver uptake, and accumulation in bone/bone marrow/joints. These effects were attributed to Ca2+-affinity and/or binding to macrophages. Despite phosphonic acids offering a high degree of water-solubility, their incorporation must be carefully considered to avoid ex-acerbating the radioligands’ pharmacokinetic behaviors.

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  • PET-Center

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Permalink: https://www.hzdr.de/publications/Publ-37446


Reduction of the electron beam divergence of laser wakefield-accelerators by integrated plamsa lens

Chang, Y.-Y.; Couperus Cabadağ, J. P.; Debus, A.; Ghaith, A.; La Berge, M.; Pausch, R.; Schöbel, S.; Ufer, P.; Schramm, U.; Irman, A.

We report on electron beam collimation using a passive plasma lens, integrated directly and conveniently into a laser wakefield accelerator stage operating in the high charge regime. The lens is created by reshaping the gas density profile of a super-sonic jet at the beam's exit side through an obstacle mounted above the jet. It reduces the beam's divergence by a factor of two to below 1 mrad (root-mean-square), while preserving the total charge of 170 pC and maintaining the energy spread. The resulting spectral-charge density, here defined as the charge per energy bandwidth and emission angle, of up to 7 pC/(MeV·mrad) played a key role in the recent experimental demonstration of free-electron lasing. The presented simple and robust gas shaping technique holds the potential to generate specific density profiles, essential for the application of adiabatic focusing or staging of accelerators.

Keywords: LWFA; Plasma Lens; PIConGPU

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  • Draco

Permalink: https://www.hzdr.de/publications/Publ-37445


Bound state breaking and the importance of thermal exchange-correlation effects in warm dense hydrogen

Moldabekov, Z.; Schwalbe, S.; Böhme, M.; Vorberger, J.; Shao, X.; Pavanello, M.; Graziani, F.; Dornheim, T.

Hydrogen at extreme temperatures and pressures is ubiquitous throughout our universe and naturally occurs in a variety of astrophysical objects. In addition, it is of key relevance for cutting-edge technological applications, with inertial confinement fusion research being a prime example. In the present work, we present exact \emph{ab initio} path integral Monte Carlo (PIMC) results for the electronic density of warm dense hydrogen along a line of constant degeneracy across a broad range of densities. Using the well-known concept of reduced density gradients, we develop a new framework to identify the breaking of bound states due to pressure ionization in bulk hydrogen. Moreover, we use our PIMC results as a reference to rigorously assess the accuracy of a variety of exchange--correlation (XC) functionals in density functional theory calculations for different density regions. Here a key finding is the importance of thermal XC effects for the accurate description of density gradients in high-energy density systems. Our exact PIMC test set is freely available online and can be used to guide the development of new methodologies for the simulation of warm dense matter and beyond.

Permalink: https://www.hzdr.de/publications/Publ-37444


Novel Liquid Distributor Concept for Rotating Packed Beds

Pyka, T.; Bieberle, A.; Loll, R.; Held, C.; Schubert, M.; Schembecker, G.

Although it is known that a loss in separation performance is caused by liquid maldistribution, there is only marginal knowledge about liquid distribution in rotating packed beds (RPBs). As a result, the exact influence of liquid distribution on separation performance in RPBs is not fully understood. Therefore, this study focuses on the influence of different liquid distributors on the liquid distribution of a rotating metal foam packing inside RPBs. Liquid hold-ups were measured non-invasively using gamma-ray computed tomography (CT), and water/air was the system under investigation, operated at atmospheric pressure, temperature of 20°C, liquid flow rate of 60 l h^-1, F-factor of 2.3 Pa^0.5 and at rotational speeds up to 900 rpm. For the first time, the liquid distribution in axial direction of a rotating metal foam of an RPB could be accessed, which allowed the identification and quantification of occurring wall flows. Furthermore, the path of the liquid phase through the entire opaque packing could be visualized for different operating conditions by synchronizing the CT scans with the rotational speed of the rotor. The use of a single-point full-jet nozzle was more prone to cause wall flow than the use of a rotating baffle distributor with 36 baffles. For comparison, circumferential liquid maldistribution was also observed using a rotating baffle distributor with 12 baffles.

Keywords: rotating packed bed; rotating baffle distributer; gamma-ray computed tomography

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  • TOPFLOW Facility

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Permalink: https://www.hzdr.de/publications/Publ-37443


SPEChpc 2021 Benchmark Suites for Modern HPC Systems

Li, J.; Bobyr, A.; Boehm, S.; Brantley, W.; Brunst, H.; Cavelan, A.; Chandrasekaran, S.; Cheng, J.; Ciorba, F. M.; Colgrove, M.; Curtis, T.; Daley, C.; Ferrato, M.; Gimenes De Souza, M.; Hagerty, N.; Henschel, R.; Juckeland, G.; Kelling, J.; Li, K.; Lieberman, R.; McMahon, K.; Melnichenko, E.; Ayoub Neggaz, M.; Ono, H.; Ponder, C.; Raddatz, D.; Schueller, S.; Searles, R.; Vasilev, F.; Melesse Vergara, V.; Wang, B.; Wesarg, B.; Wienke, S.; Zavala, M.

The SPEChpc™ 2021 suites are application-based benchmarks de-
signed to measure performance of modern HPC systems. The bench-
marks support MPI, MPI+OpenMP, MPI+OpenMP target offload,
MPI+OpenACC and are portable across all major HPC platforms.

Keywords: HPC; Benchmark; Performance Evaluation; MPI; OpenMP; OpenACC

Permalink: https://www.hzdr.de/publications/Publ-37442


Responsive Magnetic Nanocomposites for Intelligent Shape-Morphing Microrobots

Liu, Y.; Lin, G.; Medina-Sánchez, M.; Guix, M.; Makarov, D.; Jin, D.

With the development of advanced biomedical theragnosis and bioengineering tools, smart and soft responsive microstructures and nanostructures have emerged. These structures can transform their body shape on demand and convert external power into mechanical actions. Here, we survey the key advances in the design of responsive polymer−particle nanocomposites that led to the development of smart shapemorphing microscale robotic devices. We overview the technological roadmap of the field and highlight the emerging opportunities in programming magnetically responsive nanomaterials in polymeric matrixes, as magnetic materials offer a rich spectrum of properties that can be encoded with various magnetization information. The use
of magnetic fields as a tether-free control can easily penetrate biological tissues. With the advances in nanotechnology and manufacturing techniques, microrobotic devices can be realized with the desired magnetic reconfigurability. We emphasize that future fabrication techniques will be the key to bridging the gaps between integrating sophisticated functionalities of
nanoscale materials and reducing the complexity and footprints of microscale intelligent robots.

Keywords: Magnetic nanocomposites; shape-morphing; Microrobots; Magnetic reconfigurability; Stimuli-responsive materials; Scalable manufacturing approaches; Biomedical and bioengineering applications

Permalink: https://www.hzdr.de/publications/Publ-37441


Optical properties of selenium-hyperdoped Si layers: Effects of laser and thermal treatment

Komarov, F. F.; Vlasukova, L. A.; Milchanin, O. V.; Parkhomenko, I. N.; Berencen, Y.; Alzhanova, A. E.; Wang, T.; Zuk, J.

Silicon layers with a selenium impurity concentration up to 1021 cm–3, which exceeds the equilibrium solubility limit of this
impurity in silicon by four orders of magnitude, were obtained by high-dose ion implantation followed by pulsed laser
annealing at pulse energy densities from 0.5 to 2.5 J/cm2. Rutherford backscattering of He+ ions showed that up to 70% of
the implemented impurity atoms were localized at silicon crystal-lattice sites after laser annealing. The Se-hyperdoped Si
layers were characterized by increased (up to 45–55%) absorption in the spectral range 1100–2400 nm. Thermal treatment
(550°C for 30 min followed by 850°C for 5 min) did not increase the IR absorption as compared with the initial Si, which was
explained by Se losses resulting from diffusional redistribution. Recrystallization of Si layers amorphized by Se ions and
redistribution of the dopant with equilibrium thermal treatment were theoretically evaluated.

Keywords: IR-light absorption; laser annealing; selenium implantation; silicon; thermal treatment

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  • Secondary publication expected from 17.05.2024

Permalink: https://www.hzdr.de/publications/Publ-37440


Novel Mixed-Dimensional hBN-Passivated Silicon Nanowire Reconfigurable Field Effect Transistors: Fabrication and Characterization

Ghosh, S.; Bilal Khan, M.; Chava, P.; Watanabe, K.; Taniguchi, T.; Prucnal, S.; Hübner, R.; Mikolajick, T.; Erbe, A.; Georgiev, Y.

This work demonstrates the novel concept of a mixed-dimensional reconfigurable field effect transistor (RFET) by combining a one-dimensional (1D) channel material such as a silicon (Si) nanowire with a two-dimensional (2D) material as a gate dielectric. An RFET is an innovative device that can be dynamically programmed to perform as either an n- or p-FET by applying appropriate gate potentials. In this work, an insulating 2D material, hexagonal boron nitride (hBN), is introduced as a gate dielectric and encapsulation layer around the nanowire in place of a thermally grown or atomic-layer-deposited oxide. hBN flake was mechanically exfoliated and transferred onto a silicon nanowire-based RFET device using the dry viscoelastic stamping transfer technique. The thickness of the hBN flakes was investigated by atomic force microscopy and transmission electron microscopy. The ambipolar transfer characteristics of the Si-hBN RFETs with different gating architectures showed a significant improvement in the device’s electrical parameters due to the encapsulation and passivation of the nanowire with the hBN flake. Both n- and p-type characteristics measured through the top gate exhibited a reduction of hysteresis by 10–20 V and an increase in the on–off ratio (ION/IOFF) by 1 order of magnitude (up to 108) compared to the values measured for unpassivated nanowire. Specifically, the hBN encapsulation provided improved electrostatic top gate coupling, which is reflected in the enhanced subthreshold swing values of the devices. For a single nanowire, an improvement up to 0.97 and 0.5 V/dec in the n- and p-conduction, respectively, is observed. Due to their dynamic switching and polarity control, RFETs boast great potential in reducing the device count, lowering power consumption, and playing a crucial role in advanced electronic circuitry. The concept of mixed-dimensional RFET could further strengthen its functionality, opening up new pathways for future electronics.

Keywords: mixed-dimensional reconfigurable FET; ambipolar; nickel silicide; flash lamp annealing; hBN encapsulation; subthreshold swing

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  • Open Access Logo ACS Applied Materials and Interfaces 15(2023)34, 40709-40718
    Online First (2023) DOI: 10.1021/acsami.3c04808

Permalink: https://www.hzdr.de/publications/Publ-37438


On the optimal presence strategies for workplace during pandemics: A COVID-19 inspired probabilistic model

Davoodi Monfared, M.; Senapati, A.; Mertel, A.; Schlechte-Welnicz, W.; Calabrese, J.

During pandemics like COVID-19, both the quality and quantity of services offered by businesses and organizations have been severely impacted. They often have applied a hybrid home office setup to overcome this problem, although in some situations, working from home lowers employee productivity. So, increasing the rate of presence in the office is frequently desired from the manager's standpoint. On the other hand, as the virus spreads through interpersonal contact, the risk of infection increases when workplace occupancy rises.
Motivated by this trade-off, in this paper, we model this problem as a bi-objective optimization problem and propose a practical approach to find the trade-off solutions. We present a new probabilistic framework to compute the expected number of infected employees for a setting of the influential parameters, such as the incidence level in the neighborhood of the company, transmission rate of the virus, number of employees, rate of vaccination, testing frequency, and rate of contacts among the employees. The results show a wide range of trade-offs between the expected number of infections and productivity, for example, from 1 to 6 weekly infections in 100 employees and a productivity level of 65\% to 85\%. This depends on the configuration of influential parameters and the occupancy level.
We implement the model and the algorithm and perform several experiments with different settings of the parameters. Moreover, we developed an online application based on the result in this paper which can be used as a recommender for the optimal rate of occupancy in companies/workplaces.

Keywords: COVID-19; Optimization; Productivity

Permalink: https://www.hzdr.de/publications/Publ-37437


Impact of the Fuel Rod Modeling on the X2 Control Rod Cluster Ejection Results

Bilodid, Y.; Zilly, M.; Fischer, M.; Henry, R.; Kliem, S.; Alexander, A.; Kilger, R.

The new benchmark for VVER-1000 control rod ejection transient was published recently. One of the assumptions proposed in the benchmark is given fixed values for fuel-cladding gas gap thermal conductivity and thermo-physical properties of fuel and cladding materials. In this paper, authors investigate an impact of this assumption on simulation results.

Keywords: X2; VVER-1000; Control Rod Ejection; fuel-cladding gas gap thermal conductivity; thermo-physical properties of fuel and cladding

  • Contribution to proceedings
    International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2023), 13.-17.08.2023, Niagara Falls, Canada
    Proceedings of M&C 2023 International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, 978-1-926773-50-6
  • Lecture (Conference)
    International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2023), 13.-17.08.2023, Niagara Falls, Canada

Permalink: https://www.hzdr.de/publications/Publ-37436


Sulfide S-Zn-Cd isotopes and origin of the Liangyan Zn-Pb deposit in the Sichuan-Yunnan-Guizhou metallogenic province, SW China

Wu, T.; He, Y.-F.; He, Z.-W.; Huang, Z.-L.; Ye, L.; Wei, C.; Fan, H.-F.; Hu, Y.-S.; Du, L.; Gun, M.-S.

Unraveling the metal sources of Zn-Pb deposits is vital to understand the genetic types and ore-forming processes. The Sichuan-Yunnan-Guizhou metallogenic province (SYGMP) hosts abundant Zn-Pb deposits that are variably rich in critical metals such as Ga, Ge, Cd and Tl. However, sources of these critical metals and main metal Zn are still unclear. The Liangyan Cd-rich Zn-Pb deposit as a representative in the SYGMP is hosted in a carbonate sedimentary sequence and controlled by the regional Yadu-Wogong anticline and Yadu-Mangdong thrust fault. SZn-Cd isotopes of sulfide minerals from this deposit are obtained in order to understand the sources of metals and origin of the deposit. Sulfur isotopic results of pyrite and sphalerite reveal that sulfur was produced by thermochemical sulfate reduction (TSR) of sulfates from the Carboniferous dolostone and mudstone and the Ediacaran-Devonian carbonates. Sphalerite grains have δ66ZnJMC values that are negatively correlated with the δ114Cd spex values, implying different sources for both Zn and Cd. The variation trend of δ66ZnJMC and Cd/Zn
suggests that Zn was mainly sourced from the Neoproterozoic basement with minor from the Carboniferous wallrocks. Besides, sphalerite grains show a negative correlation between δ114Cdspex and Zn/Cd, and these values fall in the field close to the Carboniferous carbonates, but away from the Permian Emeishan basalts, indicating that Cd was derived mainly from the Carboniferous wallrocks with minor from the Emeishan basalts. Together with geological evidence, the multi-isotope data suggest that the Liangyan deposit belongs to a thrust-controlled MVT Zn-Pb deposit.

Keywords: Zn and Cd isotopes; Metal source; Ore genesis; Mixing of isotopically distinct sources; MVT deposit

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  • Secondary publication expected from 27.07.2024

Permalink: https://www.hzdr.de/publications/Publ-37434


ESFR-SIMPLE: new HORIZON-EURATOM project on SFR safety

Sciora, P.; Mikityuk, K.; Bonzom, P. V.; Fridman, E.; Bubelis, E.; Rineiski, A.; Hamy, J. M.; Gaus-Liu, X.; Gerbeth, Gunter; Eckert, Sven; Dupont, V.; Shwageraus, E.

Following several previous European projects (EFR, CP-ESFR and ESFR-SMART), a new project ESFR-SIMPLE has been proposed in response to the HORIZON-EURATOM call on “Safety of advanced and innovative nuclear designs and fuels”. The new project aims at challenging the Generation IV ESFR (European Sodium Fast Reactor) designed in the ESFR-SMART project, to improve its safety and economics thanks to innovative technologies. The project high-level objectives and actions are: 1) Challenge the ESFR design to simplify the reactor, through reducing its size, which could allow taking advantage of SMRs (Small Modular Reactors) in terms of transportability, modularization, standardization, flexible operation and machine learning, all ultimately leading to improved economics. 2) Propose, develop and assess advanced methods of monitoring and processing operational data using Artificial Intelligence, e.g., to optimize fault detection in the steam generators at an early stage. 3) Produce new experimental data in order to support calibration and validation of the computational tools such as properties measurements of irradiated and non-irradiated MOX fuel including fuel with optimized micro-structures, and to assist in qualification of innovative components, such as expansion bellows, thermo-electric pumps and accident tolerant core-catcher. 4) Assess alternative technologies, such as the use of metallic fuel and compact secondary system design, for the large-size ESFR to improve the economics and safety. 5) Ensure that the knowledge generated in the project will be shared not only among the project partner institutions, but also among as wide a range of stakeholders as possible in Europe and internationally. The project relies on a consortium of 16 partners and will benefit from different skills and experiments available in Europe and in the US. It started in October 2022 and will end in September 2026. In addition to the technical details, this paper also briefly outlines the organization of the project.

  • Contribution to proceedings
    International Congress on Advances in Nuclear Power Plants (ICAPP 2023), 23.-27.04.2023, Gyeongju, South Korea

Permalink: https://www.hzdr.de/publications/Publ-37433


First Direct Measurement Constraining the 34Ar(α,p)37K Reaction Cross Section for Mixed Hydrogen and Helium Burning in Accreting Neutron Stars

Browne, J.; Chipps, K. A.; Schmidt, K.; Schatz, H.; Ahn, S.; Pain, S. D.; Montes, F.; Ong, W.-J.; Greife, U.; Allen, J.; Bardayan, D. W.; Blackmon, J. C.; Blankstein, D.; Cha, S.; Chae, K. Y.; Febbraro, M.; Hall, M. R.; Jones, K. L.; Kontos, A.; Meisel, Z.; O’Malley, P. D.; Schmitt, K. T.; Smith, K.; Smith, M. S.; Thompson, P.; Toomey, R.; Vostinar, M.; Walter, D.

The rate of the final step in the astrophysical αp process, the 34Ar(α,p)37K reaction, suffers from large uncertainties due to a lack of experimental data, despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars. We present the first direct measurement constraining the 34Ar(α,p)37K reaction cross section, using the Jet Experiments in Nuclear Structure and Astrophysics gas jet target. The combined cross section for the 34Ar,Cl(α,p)37K,Ar reaction is found to agree well with Hauser-Feshbach predictions. The 34Ar(α,2p)36Ar cross section, which can be exclusively attributed to the 34Ar beam component, also agrees to within the typical uncertainties quoted for statistical models. This indicates the applicability of the statistical model for predicting astrophysical (α,p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.

Keywords: experimental nuclear astrophysics; JENSA gas jet target; x-ray burst; accreting neutron star; nuclear reaction study; TALYS; light curve; nuclear ashes

Permalink: https://www.hzdr.de/publications/Publ-37432


Providing AI expertise as an infrastructure in academia

Piraud, M.; Camero, A.; Götz, M.; Kesselheim, S.; Steinbach, P.; Weigel, T.

Artificial intelligence (AI) is proliferating and developing faster than any domain scientist can adapt. To support the scientific enterprise in the Helmholtz association, a network of AI specialists has been set up to disseminate AI expertise as an infrastructure among domain scientists. As this effort exposes an evolutionary step in science organization in Germany, this article aspires to describe our setup, goals, and motivations. We comment on past experiences, current developments, and future ideas as we bring our expertise as an infrastructure closer to scientists across our organization. We hope that this offers a brief yet insightful view of our activities as well as inspiration for other science organizations.

Keywords: machine learning; artificial intelligence; consulting; consultants; expertise; infrastructure; service; science

Permalink: https://www.hzdr.de/publications/Publ-37431


Increased cerebral blood flow is associated with higher baseline amyloid burden in a cognitively unimpaired population

Padrela, B. E.; Lorenzini, L.; Collij, L. E.; Tomassen, J.; Bader, I.; Shekari, M.; van Berckel, B. N. M.; Visser, P. J.; Barkhof, F.; Petr, J.; Mutsaerts, H.-J.

Background:

Decreased cerebral blood flow (CBF) and deterioration of blood-brain barrier (BBB) are suggested to be precursor conditions of cognitive impairment. Using a novel multi-echo-time arterial spin labelling (ASL) protocol, we examined the time of exchange (Tex) of water across the BBB as a measurement of BBB permeability. We further examined the association of cardiovascular risk factors with Tex in an ongoing cohort study.
Method:
Data (n=29, mean age: 55.9±6.1years, 69% women) were drawn from Neurological biomarkers of Blood, MRI and Cognition (NEURO-BMC) study performed at National University of Singapore. NEURO-BMC is an ongoing prospective cohort study (age: 45-65 years) on brain changes in a subclinical phase of cognitive impairment. A multi-echo, Hadamard-encoded multi-post-labelling-delay pseudo-continuous ASL (PCASL) protocol was used on a 3T scanner. ExploreASL was used with a modified version of FSL FABBER(4) to quantify cerebral blood flow (CBF), arterial transit time (ATT), and Tex. ASL-extracted parameters were compared with cardiovascular risk parameters such as blood pressure (BP), BMI and smoking status.
Result:
High systolic and diastolic BP were associated with significantly reduced Tex (Fig 1). Additionally, higher systolic and diastolic BP showed a trend of increased ATT and reduced CBF, though the associations were not statistically significant (Table 1). High BMI had a significant association with increased ATT and reduced CBF. However, no trend was observed between BMI and Tex. Participants who ever smoked were observed to have a reduced Tex and CBF and increased ATT, but statistical significance was only found for CBF (Fig 1).
Conclusion:
In this pilot study, we showed that BBB-ASL-derived parameters - ATT, CBF, and Tex - were associated with BP, BMI, and smoking status. While the sample size for this preliminary analysis was too small to make a definitive conclusion as not all associations were statistically significant, all studied cardiovascular risk factors showed their potential in increasing the risk of BBB deterioration. Further investigation with a larger sample size and other health risk factors to assess these observations is warranted.

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  • DRESDYN
  • Open Access Logo Contribution to proceedings
    Alzheimer's Association International Conference, 16.07.2023, Amsterdam, Amsterdam
    DOI: 10.1002/alz.065779
  • Poster
    Alzheimer's Association International Conference, 16.07.2023, Amsterdam, The Netherlands

Permalink: https://www.hzdr.de/publications/Publ-37430


Coherent x-ray diffraction of a semiregular Pt nanodot array

Keller, T. F.; Shayduk, R.; Kim, C.; Mukharamova, N.; Dangwal Pandey, A.; Abuin, M.; Vonk, V.; Fernandez-Cuesta, I.; Barthelmess, M.; Frömter, R.; Zozulya, A.; Erbe, A.; Stierle, A.

Structural insight into nano-objects down to the atomic scale is one of the most important prerequisites in understanding functional materials properties and will ultimately permit to relate the size and shape of nanoparticles to their catalytic activity. We elucidate the potential of extracting structural information about a small ensemble of nanoparticles semi-regularly arranged on a periodic array from coherent X-ray Bragg diffraction. The observed superstructure in the Pt(111) Bragg peak obviously originates from the mutual interference of the Bragg scattered wave field from individual nanoparticles in the nano-array. Despite the absence of a symmetry center in the Bragg peak of the nano-array, we identify the most prominent in-plane spatial frequencies of the latter by applying a Patterson map analysis to the Bragg peak superstructure. Integration along the out-of-plane reciprocal space direction over the relevant in-plane regions of interest results in Laue oscillations that arise from nanoparticle sets of similar heights in real space. A one-to-one comparison with real-space microscopic information obtained from SEM and AFM suggests potential nanoparticle subsets as origin for the X-ray intensity in these regions of interest by the good agreement in their height and direction-dependent in-plane interparticle distances, as also further supported by simulations. Nanoparticle arrays with well-defined tunable sizes and lateral distances may serve in the future to track structural changes of smallest catalysis-relevant nanoparticles during operando heterogeneous catalysis experiments in the 10 nm size regime.

Keywords: Coherent X-ray Bragg diffraction; platinum nanodot-array; strontium titanate; electron beam lithography

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Permalink: https://www.hzdr.de/publications/Publ-37429


On the application of advanced modeling tools to the SLB analysis in NuScale. Part I: TRACE/PARCS, TRACE/PANTHER and ATHLET/DYN3D

Sanchez-Torrijos, J.; Redondo-Valero, E.; Queral, C.; Cabellos, O.; Meca, R.; Petrásek, O.; Diaz Pescador, E.; Kliem, S.; Palmans, N.; Sanchez-Espinoza, V.

Nowadays, there is a growing interest in the Small Modular Reactors (SMRs) technology due to their enhanced safety level and reasonably reduced manufacturing and construction costs. However, modeling tools should be able to deal with the special features inherent to their design such as the modeling of the helical Steam Generators. In this work, a Steam Line Break sequence in the NuScale reactor has been simulated using several modeling tools based on a full-plant thermohydraulic model for a system code coupled with a 3D nodal diffusion code for describing the core physics. To do so, four different models have been developed by four different organization for the coupled codes TRACE/PARCS, TRACE/PANTHER and ATHLET/DYN3D. In that sense, a very reasonable agreement is reached among the steady-state parameters of the plant computed by each participant and the ones presented in the Design Standard Application Report of NuScale. Regarding the simulation of the SLB transient, it should be noted that after 100 seconds of simulation, it can be said that remarkable differences are to be seen among the results for the time behavior of the core temperatures. Those differences are attributable to differences in the heat transfer within the helically coiled steam generators. Important differences have been also found in the decay heat removal system performance, so it is concluded that further investigation and model development is needed for the phenomena occurring in the steam generators and the decay heat removal heat system.

Keywords: NuScale; McSAFER; Steam Line Break; Coupled codes

  • Contribution to proceedings
    2023 International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M&C 2023, 13.-17.08.2023, Niagara Falls, Canada
    Proceedings of the 2023 International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M&C 2023, 978-1-926773-50-6
  • Lecture (Conference)
    2023 International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M&C 2023, 13.-17.08.2023, Niagara Falls, Canada

Permalink: https://www.hzdr.de/publications/Publ-37428


Review and recommendations on deformable image registration uncertainties for radiotherapy applications

Nenoff, L.; Amstutz, F.; Murr, M.; Archibald-Heeren, B.; Fusella, M.; Hussein, M.; Lechner, W.; Zhang, Y.; Sharp, G.; Vasquez Osorio, E.

Deformable image registration (DIR) is a versatile tool used in many applications in radiotherapy (RT). DIR algorithms have been implemented in many commercial treatment planning systems providing accessible and easy-to-use solutions. However, the geometric uncertainty of DIR can be large and difficult to quantify, resulting in barriers to clinical practice. Currently, there is no agreement in the RT community on how to quantify these uncertainties and determine thresholds that distinguish a good DIR result from a poor one. This review summarises the current literature on sources of DIR uncertainties and their impact on RT applications. Recommendations are provided on how to handle these uncertainties for patient-specific use, commissioning, and research. Recommendations are also provided for developers and vendors to help users to understand DIR uncertainties and make the application of DIR in RT safer and more reliable.

Keywords: deformable image registration; DIR uncertainty; radiotherapy; structure propagation; dose accumulation; mapping; image deformation

Permalink: https://www.hzdr.de/publications/Publ-37427


CEFR control rod drop transient simulation using RAST-F code system

Tran, T. Q.; Huo, X.; Fridman, E.; Lee, D.

This study aimed to verify and validate the transient simulation capability of the hybrid code system RAST-F for fast reactor analysis. For this purpose, control rod (CR) drop experiments of eight CRs and six control groups in the China Experimental Fast Reactor (CEFR) start-up tests were utilized to simulate the CR drop transient. The RAST-F numerical solution, including the neutron population, time-dependent reactivity, and CR worth, was compared against the measurement values obtained from two out-of-core detectors. Moreover, the time-dependent reactivity and CR worth from RAST-F were verified against the results obtained by the Monte Carlo code Serpent using continuous energy nuclear data. A code-to-code comparison between Serpent and RAST-F showed good agreement in terms of time-dependent reactivity and CR worth. The discrepancy was less than 160 pcm for reactivity and less than 110 pcm for CR worth. RAST-F solution was almost identical to the measurement data in terms of neutron population and reactivity. All the calculated CR worth results agreed with experimental results within two standard deviations of experimental uncertainty for all CRs and control groups. This work demonstrates that the RAST-F code system can be a potential tool for analyzing time-dependent phenomena in fast reactors.

Keywords: CEFR; RAST-F; Transient; Nodal diffusion code; Serpent

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Permalink: https://www.hzdr.de/publications/Publ-37426


Prompt gamma-ray spectroscopy in conjunction with the Monte Carlo Library Least Squares approach: applications to range verification in proton therapy

Skjerdal, K.; Kögler, T.; Lionheart, W.; Smeland Ytre-Hauge, K.; Meric, I.

Prompt Gamma-ray Spectroscopy (PGS) in conjunction with the Monte Carlo Library Least Squares (MCLLS) approach was investigated for the purposes of range monitoring in proton therapy through Monte Carlo simulations. Prompt gamma-rays are produced during treatment and can be correlated to the range of the proton beam in the tissue. In contrast to established approaches, MCLLS does not rely on the identification of specific photopeaks. Instead it treats each individual constituent as a library spectrum and calculates coefficients for each spectrum, and therefore takes both the photopeaks and the Compton continuum into account. It can thus be applied to organic scintillators traditionally not used for energy spectroscopy due to their low Z number and density. Preliminary results demonstrate that the proposed approach returns a strong linear correlation between the range of the primary proton beam and the calculated library coefficients, depending on the composition of libraries. This can be exploited for range monitoring.

Keywords: proton therapy; spectroscopy; Monte Carlo simulations; range verification

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  • Open Access Logo Contribution to proceedings
    ANIMMA 2023 – Advancements in Nuclear Instrumentation Measurement Methods and their Applications, 12.-16.06.2023, Real Collegio, Italy
    ANIMMA 2023 Conference Proceedings: EPJ Web of Conferences
    DOI: 10.1051/epjconf/202328809003

Permalink: https://www.hzdr.de/publications/Publ-37424


Morphology and orientation change of layer-by-layer deposited one- and two-dimensional coordination polymer nanocrystals containing rhodium paddle-wheel units

Steinbach, D.; Neubert, R.; Gersdorf, S.; Schimpf, C.; Erb, D.; Rafaja, D.; Plamper, F. A.; Mertens, F.

Surface-directed and preferentially oriented assemblies of nanomaterials can enable enhanced applications in e.g. catalysis or sensing. Coordination polymers, which can be even conducting, could be suitable materials for this purpose because of their facile surface anchoring. Hence, we coassembled rhodium paddle-wheel building blocks with bi- or trifunctional linkers in dip coatings that were produced by layer-by-layer approach on silicon wafers functionalized by thin nanocrystalline gold surfaces. These gold surfaces were decorated with a self-assembled monolayer (SAM) for coordination and binding to the Rh-units. As linkers, pyrazine, triazine and melamine were used, leading to rectangularly-shaped, hexagonally-shaped or needle-like crystals, respectively. The coordination polymers were produced by repeated dipping into the linker and paddle-wheel solution, each followed by a cleaning step. The crystals growth was followed by atomic force microscopy (AFM) grazing incidence small-angle X-ray scattering (GISAXS) and grazing incidence wide-angle X-ray scattering (GIWAXS). AFM and GISAXS revealed the shape and size of the crystals. GIWAXS disclosed their preferred orientation. It turned out that the automated dipping procedure does not lead to a strong alignment of crystallites along the dipping direction for the pyrazine-based deposits. However, these crystals are preferentially oriented with respect to the substrate normal direction. The crystallographic direction and the degree of the alignment depend on the number of deposition cycles. In the early phases of the deposition process, predominantly “lying” crystals were detected. With increasing number of the deposition cycles, the fraction of “standing” crystals became dominant. These crystals are oriented with their {010} directions perpendicular to the surface of the substrate. Still, “lying” and some tilted crystals were detected additionally. The study gives a deeper structural understanding of crystallite assemblies and suggests an evolvement of more anisotropic orientations of the crystallites with increasing deposition cycles (leading to the prevalence of crystals having the preferred {010} orientation with respect to the surface normal direction).

Permalink: https://www.hzdr.de/publications/Publ-37423


Overcoming stereological Bias: A workflow for 3D mineral characterization of particles using X-ray micro-computed tomography

Siddique, A.; Da Assuncao Godinho, J. R.; Sittner, J.; Pereira, L.

Mineral separation processes operate on properties of individual particle, which can currently be quantified with 2D
characterization techniques, namely 2D automated mineralogy. While 2D automated mineralogy data have driven significant
developments in particle-based separation models, this data inherently correspond to 2D slices of 3D objects, which leads to
stereological bias in the quantification of geometric particle properties. X-ray micro-computed tomography (μCT) is a 3D
imaging technique that can quantify particle geometry. However, μCT only collects limited information regarding material
composition, making mineral identification quantification a challenge. To overcome this challenge, we present a workflow
that utilizes individual particle histograms and corrects image artefacts caused by μCT measurements, such as partial
volume effect. We demonstrate the application of the workflow to perform 3D mineral characterisation of a sulfidic gold ore,
where mineral phases that are commonly mistaken with μCT could be distinguished: pyrite and chalcopyrite, gold, and
galena. Results were verified by comparison with inductively coupled plasma mass spectrometry and 2D automated
mineralogy. As a result, the workflow provides the user with a detailed 3D particle dataset containing the modal mineralogy
and surface compositions, size, and geometrical properties of each particle in a sample – essential data for modelling
mineral separation processes.

Keywords: 2D automated mineralogy; 3D mineral characterization; Individual particle histograms; Mineral separation processes; X-ray micro-computed tomography

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  • Secondary publication expected from 28.04.2024

Permalink: https://www.hzdr.de/publications/Publ-37422


Highly Enhanced Defects Driven Room Temperature Ferromagnetism in Mixed-phase MoS2-MoOx Films

Singh, P.; Ghosh, S.; Jain, M.; Singh, A.; Singh, R.; Balal, M.; Roy Barman, S.; Kentsch, U.; Zhou, S.; Bhattacharya, S.; Srivastava, P.

Room temperature ferromagnetism has been reported in chemical vapor deposition-grown mixed-phase MoS2-MoOx thin films after Xe ion irradiation. Magnetic moment has significantly been enhanced after ion irradiation. Deterioration in crystallinity after ion irradiation has been shown by X-ray diffraction and Raman spectroscopy measurements. The variation in the surface morphology and/or formation of edge states can be observed by secondary electron microscopy images. The reduction in the oxygen vacancy concentration, probed by analysis of the O 1s core level X-ray photoelectron spectrum for the film with the maximum magnetic moment, rules out the possibility of ferromagnetism due to oxygen vacancy. Enhancement in the Mo content in 5+ and 6+ oxidation states due to the occupation of sulfur vacancy sites by oxygen after ion irradiation, calculated from X-ray photoelectron spectroscopy core level of Mo 3d and S 2p and valence band spectra, has been observed. Density functional theory (DFT) calculations also show the one-to-one correspondence of saturation magnetic moment with Mo6+ content. So, the enhancement in the ferromagnetism in mixed-phase of MoS2-MoOx thin films is due to the increase of Mo in 6+ oxidation state and exchange interaction between the different oxidation states of Mo via p-orbital of anion and formation of edged states.

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Permalink: https://www.hzdr.de/publications/Publ-37421


Ion irradiation of monolayer graphene-Nd:YAG hybrid waveguides: fabrication and laser

Ma, L.; Li, S.; Wang, H.; Zhou, S.; Yang, T.

Hybrid waveguides consisting of two-dimensional layered materials pad on the surface of optical waveguides suffer from a nonuniform and loose contact between the two-dimensional material and the waveguide, which can reduce the efficiency of the pulsed laser. Here, we present high-performance passively Q-switched pulsed lasers in three distinct structures of monolayer graphene-Nd:YAG hybrid waveguides irradiated by energetic ions. The ion irradiation enables the monolayer graphene a tight contact and strong coupling with the waveguide. As a result, Q-switched pulsed lasers with narrow pulse width and high repetition rate are obtained in three designed hybrid waveguides. The narrowest pulse width is 43.6 ns, provided by the ion-irradiated Y-branch hybrid waveguide. This study paves the way toward developing on-chip laser sources based on hybrid waveguides by using ion irradiation.

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Permalink: https://www.hzdr.de/publications/Publ-37420


Ferromagnetic interlayer coupling in CrSBr crystals irradiated by ions

Long, F.; Ghorbani Asl, M.; Mosina, K.; Li, Y.; Lin, K.; Ganss, F.; Hübner, R.; Sofer, Z.; Dirnberger, F.; Kamra, A.; Krasheninnikov, A.; Prucnal, S.; Helm, M.; Zhou, S.

Layered magnetic materials are becoming a major platform for future spin-based applications. Particularly the air-stable van der Waals compound CrSBr is attracting considerable interest due to its prominent magneto-transport and magneto-optical properties. In this work, we observe a transition from antiferromagnetic to ferromagnetic behavior in CrSBr crystals exposed to high-energy, non-magnetic ions. Already at moderate fluences, ion irradiation induces a remanent magnetization with hysteresis adapting to the easy-axis anisotropy of the pristine magnetic order up to a critical temperature of 110 K. Structure analysis of the irradiated crystals in conjunction with density functional theory calculations suggest that the displacement of constituent atoms due to collisions with ions and the formation of interstitials favors ferromagnetic order between the layers.

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Permalink: https://www.hzdr.de/publications/Publ-37419


[18F]RM273 – A PET probe for the imaging of the sigma2 receptor in brain cancer

Gündel, D.; Toussaint, M.; Moldovan, R.-P.; Teodoro, R.; Schepmann, D.; Wünsch, B.; Ludwig, F.-A.; Fischer, S.; Brust, P.; Deuther-Conrad, W.

The sigma2 receptor (TMEM97) expression correlates well with the Ki67 expression in tumours [1, 2] and therefore represents an attractive marker for the proliferative status. We developed the 18F-labelled radioligand [18F]RM273 for sigma2 receptor imaging in brain tumours.
[18F]RM273 (2-[4-(6-[18F]fluoro-1H-pyrrolo[2,3-b]pyridin-1-yl)butyl]-6,7-dimethoxy-1,2,3,4-tetra-hydroisoquinoline) has been obtained by automated synthesis by Cu-mediated oxidative radiofluorination of the aryl boronic acid pinacol ester precursor. Radiometabolite analysis was performed in mouse plasma samples 30 min p.i. The target specificity was investigated by in vitro autoradiographic studies with or without the sigma2 receptor antagonist ISO-1 in rat brain cryosections with a stereotactically implanted F98 glioma [3]. The biodistribution of [18F]RM273 in healthy mice (female, CD1; n = 4; 7.2 ± 1.1 MBq) and the tumour uptake into the F98 glioma (male, Fischer rats; n = 2; 21 and 25 MBq) were investigated by dynamic PET imaging for 60 min (nanoScan®PET-1T MRI, Mediso).
Polar radiometabolites of [18F]RM273 (AM 69 – 233 GBq/μmol, RCY 8%) were detectable in plasma, but not in brain extracts. We determined a 3-times higher density of binding sites in tumour compared to healthy brain in vitro [3]. PET studies revealed a TAC peak value of 1.3 at 2.25 min p.i. followed by a wash out in the brain of healthy mice [3]. In the F98 glioma brain region a two times higher uptake (SUVmean of 0.8–1.3 at 30–60 min p.i.) compared to contralateral was observable. Therefore, [18F]RM273 could potentially be used to determine the proliferative status of brain tumours.
Acknowledgements: This work was supported by the Deutsche Forschungsgemeinschaft (DFG: BR 1360/13-1).
References: [1] Shoghi et al. Plos One 2013, 8: e74188; [2] Yang et al. Molecules 2020, 25 (22): 5439 [3] Moldovan et al. Int. J. Mol. Sci. 2021, 22: 5447

Keywords: Sigma 2 recceptor; glioma; PET; [18F]RM273

  • Poster
    PET iS Wonderful, 23.-24.10.2023, Edinburgh, Scotland
  • Lecture (Conference)
    PET Is Wonderful, 23.-24.10.2023, Edinburgh, Scotland

Permalink: https://www.hzdr.de/publications/Publ-37418


Development of a Highly Specific 18F-labeled Radioligand for Imaging of Sigma-2 Receptor in Brain Tumor

Wang, T.; Wang, J.; Chen, L.; Zhang, X.; Mou, T.; An, X.; Zhang, J.; Zhang, X.; Deuther-Conrad, W.; Huang, Y.; Jia, H.

Series of novel ligands with the 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline or 5,6-dimethoxyisoindoline pharmacophore were designed and synthesized for evaluation of their structure-activity relationship to the sigma-2 (2) receptor and development as suitable PET radioligands. Compound 1 was found to possess nanomolar affinity (6.97 nM) for the 2 receptor, high subtype selectivity (58-fold) and high selectivity over 40 other receptors and transporters. Radioligand [18F]1 was prepared with radiochemical yield of 37–54%, > 99% radiochemical purity, molar activity of 107–189 GBq/μmol. Biodistribution and blocking studies in mice and micro-PET/CT imaging of [18F]1 in rats indicated excellent binding specificity of [18F]1 to the 2 receptors in vivo. Micro-PET/CT imaging of [18F]1 in the U87MG glioma xenograft model demonstrated clear tumor visualization with high tumor uptake and tumor-to-background ratio. Co-injection with CM398 (5 mol/kg) led to remarkable reduction of tumor uptake (80%, 60–70 min), indicating high specific binding of [18F]1 in U87MG glioma xenografts.

Keywords: 2 receptor; benzimidazolone derivative; brain tumor; positron emission tomography; fluorine-18

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  • Secondary publication expected from 13.09.2024

Permalink: https://www.hzdr.de/publications/Publ-37417


Acoustically induced spin resonances of silicon-vacancy centers in 4H-SiC

Vasselon, T.; Hernandez-Mınguez, A.; Hollenbach, M.; Astakhov, G.; Santos, P. V.

The long-lived and optically addressable spin states of silicon vacancies (VSi) in 4H-SiC make them promising qubits for quantum communication and sensing. These color centers can be created in both the hexagonal (V1) and in the cubic (V2) local crystallographic environments of the 4H-SiC host. While the spin of the V2 center can be efficiently manipulated by optically detected magnetic resonance at room temperature, spin control of the V1 centers above cryogenic temperatures has been elusive. Here, we show that the dynamic strain of surface acoustic waves can overcome this limitation and efficiently excite magnetic resonances of V1 centers up to room temperature. Based on the width and temperature dependence of the acoustically induced spin resonances, we attribute them to transitions between spin sublevels in the excited state. The acoustic spin control of both V1 and V2 centers in their excited states opens new ways for applications in quantum technologies based on spin-optomechanics.

Keywords: Quantum technologies; Acoustic; Spintronics; Defects; Silicon carbide

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Permalink: https://www.hzdr.de/publications/Publ-37416


Dataset on European Project ENTENTE Deliverable D4.5 "Hybrid hardening models from SANS and nanoindentation experiments

Bergner, F.; Altstadt, E.; Brandenburg, J.-E.; Chekhonin, P.; Ulbricht, A.

This dataset covers experimental data obtained for neutron-irradiated reactor pressure vessel (RPV) steels, in detail type and composition of steels, initial microstructure, initial properties, irradiation conditions, irradiation-induced microstructure changes and irradiation-induced property changes. The metadata sections of the data compilation include references to published journal articles and reports, where the data were originally published. A special feature of the data compilation is the availability of the characteristics of irradiation-induced nm-sized solute atom clusters derived from small-angle neutron scattering (SANS) experiments for each of the RPV materials and irradiation conditions considered. These characteristics, including cluster volume fraction and size, are statistically reliable and macroscopically representative. Moreover, results of Vickers hardness tests obtained using the same samples and also probing macroscopic volumes are provided. The data compilation is organized in the format of an Excel workbook called SANS-RPV. There are numerous potential applications of the data compilation such as the comparison of cluster characteristics derived from SANS and APT experiments, the correlation between cluster volume fraction and irradiation-induced hardness increase or brittle-ductile transition temperature shift, microstructure-informed predictions of the initial yield stress or irradiation-induced yield stress increase or the assessment of embrittlement trend curce (ETC) models, to mention a few. As an illustration, selected applications are saved in a separate Excel file called SANS_RPV_Analyses, which is included in the dataset. The background and usage of the data compilation as well as applications and implications are part of a study performed within the European Project ENTENTE. A copy of the project report draft (Deliverable D4.5) is included in the dataset.

Keywords: Reactor pressure vessel steels; Neutron irradiation; Microstructure; Mechanical properties; Hardening; Embrittlement; Small-angle neutron scattering

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Permalink: https://www.hzdr.de/publications/Publ-37415


Numerical Simulation of Particles in Rising Gas Bubbles

Mathew, A. T.; Maestri, R.; Lecrivain, G.

Numerical Simulation of Particles in Rising Gas Bubbles

Keywords: Taylor bubble; Simulation; Computational Fluid Dynamics

  • Study thesis
    TUBAF, 2023
    Mentor: Maestri, Rhandrey; Lecrivain, Gregory

Permalink: https://www.hzdr.de/publications/Publ-37414


Curvilinear and 3D micromagnetism: geometrically curved ferro- and antiferromagnets

Makarov, D.

Curvilinear magnetism is a framework, which helps understanding the impact of geometrical curvature on complex magnetic responses of curved 1D wires and 2D shells [1-3]. The lack of inversion symmetry and emergence of curvature induced anisotropy and Dzyaloshinskii-Moriya interaction (DMI) stemming from the exchange interaction [4,5] are characteristic of curved surfaces. Recently, a non-local chiral symmetry breaking was discovered [6], which is responsible for the coexistence and coupling of multiple magnetochiral properties within the same magnetic object [7].
Regarding antiferromagnets, it is demonstrated that intrinsically achiral one-dimensional curvilinear antiferromagnets behave as a chiral helimagnet with geometrically tunable DMI, orientation of the Neel vector and the helimagnetic phase transition [8-10]. This positions curvilinear antiferromagnets as a platform for geometrically tunable antiferromagnetic spinorbitronics.

[1] D. Makarov et al., Curvilinear micromagnetism: from fundamentals to applications (Springer, Zurich, 2022).
[2] D. Makarov et al., Adv. Mat. 34, 2101758 (2022).
[3] D. Sheka et al., Small 18, 2105219 (2022).
[4] Y. Gaididei et al., PRL 112, 257203 (2014).
[5] O. Volkov et al., PRL 123, 077201 (2019).
[6] D. Sheka et al., Commun. Phys. 3, 128 (2020).
[7] O. Volkov et al., Nature Com. 14, 1491 (2023).
[8] O. Pylypovskyi et al., Nano Lett. 20, 8157 (2020).
[9] O. Pylypovskyi et al., APL 118, 182405 (2021).
[10] Y. Borysenko et al., PRB 106, 174426 (2022).

Keywords: curvilinear magnetism; 3D nanostructures

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  • Invited lecture (Conferences)
    68th Annual Conference on Magnetism and Magnetic Materials, 30.10.-03.11.2023, Dallas, USA

Permalink: https://www.hzdr.de/publications/Publ-37413


Curvilinear and 3D low-dimensional magnetic architectures in research and technology

Makarov, D.

Extending 2D structures into 3D space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics, superconductivity and magnetism [1,2]. This approach provides means to modify conventional or to launch novel functionalities by tailoring curvature and 3D shape of magnetic thin films and nanowires [2,3]. In this talk, we will address fundamentals of curvature-induced effects in magnetism and review current application scenarios. In particular, we will demonstrate that curvature allows tailoring fundamental anisotropic and chiral magnetic interactions [4] and enables fundamentally new non-local chiral symmetry breaking effect [5,6]. Application potential of geometrically curved magnetic architectures is currently being explored as mechanically reshapeable magnetic field sensors for automotive applications, memory, spin-wave filters, high-speed racetrack memory devices, magnetic soft robotics [7] as well as on-skin interactive electronics relying on thin films [8,9,10] as well as printed magnetic composites [11,12,13].

[1] P. Gentile et al., Electronic materials with nanoscale curved geometries. Nature Electronics (Review) 5, 551 (2022).
[2] D. Makarov et al., New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures. Advanced Materials (Review) 34, 2101758 (2022).
[3] D. Makarov et al., Curvilinear micromagnetism: from fundamentals to applications (Springer, Zurich, 2022).
[4] O. Volkov et al., Experimental observation of exchange-driven chiral effects in curvilinear magnetism. Physical Review Letters 123, 077201 (2019).
[5] D. D. Sheka et al., Nonlocal chiral symmetry breaking in curvilinear magnetic shells. Communications Physics 3, 128 (2020).
[6] O. M. Volkov et al., Chirality coupling in topological magnetic textures with multiple magnetochiral parameters. Nature Communications 14, 1491 (2023).
[7] M. Ha et al., Reconfigurable Magnetic Origami Actuators with On-Board Sensing for Guided Assembly. Advanced Materials 33, 2008751 (2021).
[8] G. S. Canon Bermudez et al., Magnetosensitive e-skins for interactive devices. Advanced Functional Materials (Review) 31, 2007788 (2021).
[9] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[10] G. S. Canon Bermudez et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoception and interactive electronics. Nature Electronics 1, 589 (2018).
[11] M. Ha et al., Printable and Stretchable Giant Magnetoresistive Sensors for Highly Compliant and Skin-Conformal Electronics. Advanced Materials 33, 2005521 (2021).
[12] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Adv. Mater. Technol. 7, 2200227 (2022).
[13] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).

Keywords: curvilinear magnetism; magnetic solitons; printed magnetoelectronics; shapeable magnetic field sensors

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  • Invited lecture (Conferences)
    XII-Latin American Workshop on Magnetism, Magnetic Materials & their Applications, 16.-20.10.2023, Puerto Varas, Chile

Permalink: https://www.hzdr.de/publications/Publ-37412


From curvilinear magnetism to shapeable magnetoelectronics

Makarov, D.

Extending 2D structures into 3D space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics, superconductivity and magnetism [1,2]. This approach provides means to modify conventional or to launch novel functionalities by tailoring curvature and 3D shape of magnetic thin films and nanowires [2,3]. In this talk, we will address fundamentals of curvature-induced effects in magnetism and review current application scenarios. In particular, we will demonstrate that curvature allows tailoring fundamental anisotropic and chiral magnetic interactions [4] and enables fundamentally new non-local chiral symmetry breaking effect [5,6]. Application potential of geometrically curved magnetic architectures is currently being explored as mechanically reshapeable magnetic field sensors for automotive applications, memory, spin-wave filters, high-speed racetrack memory devices as well as on-skin interactive electronics relying on thin films [7,8] as well as printed magnetic composites [9] with appealing self-healing performance [10].

Reference list
[1] P. Gentile et al., Electronic materials with nanoscale curved geometries. Nature Electronics (Review) 5, 551 (2022).
[2] D. Makarov et al., New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures. Advanced Materials (Review) 34, 2101758 (2022).
[3] D. Makarov et al., Curvilinear micromagnetism: from fundamentals to applications (Springer, Zurich, 2022).
[4] O. Volkov et al., Experimental observation of exchange-driven chiral effects in curvilinear magnetism. Physical Review Letters 123, 077201 (2019).
[5] D. D. Sheka et al., Nonlocal chiral symmetry breaking in curvilinear magnetic shells. Communications Physics 3, 128 (2020).
[6] O. M. Volkov et al., Chirality coupling in topological magnetic textures with multiple magnetochiral parameters. Nature Communications 14, 1491 (2023).
[7] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[8] G. S. Canon Bermudez et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoception and interactive electronics. Nature Electronics 1, 589 (2018).
[9] M. Ha et al., Printable and Stretchable Giant Magnetoresistive Sensors for Highly Compliant and Skin-Conformal Electronics. Advanced Materials 33, 2005521 (2021).
[10] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).

Keywords: curvilinear magnetism; shapeable magnetoelectronics; printed magnetoelectronics; soft magnetic composites

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  • Invited lecture (Conferences) (Online presentation)
    NATO advanced research workshop "Functional Spintronic Nanomaterials 
for Radiation Detection and Energy Harvesting", 25.-27.09.2023, Kyiv, Ukraine

Permalink: https://www.hzdr.de/publications/Publ-37411


Development of Zinc Targetry: Production of diagnostic 67Ga and theranostic 67Cu

Brühlmann, S. A.; Walther, M.; Kreller, M.; Reissig, F.; Pietzsch, H.-J.; Knieß, T.; Kopka, K.

Objectives: Radionuclide availability plays a key role for development of new radiopharmaceuticals. Moreover, theranostic matched pairs of radionuclides have aroused interest in the last couple of years. On the one hand, 68Ga has been used as a diagnostic counterpart to the therapeutic β--emitter 177Lu, however, due to its short half-life (68 min), further alternatives have to be considered. In particular 67Ga (half-life: 3.26 d) as the longest-lived of the radiogallium isotopes has γ-lines that can be used for SPECT imaging (93.3 keV, 184 keV). On the other hand, 67Cu is referred as a theranostic radionuclide due to its β--emission and γ-emission suitable for SPECT, forming a perfect matched pair with the PET radionuclides 61/64Cu. At HZDR the zinc targetry and target chemistry developed for 67Cu production [1] has been applied to produce 67Ga.

Methods: 67Cu production consisted of proton irradiation (16.8 MeV, 60 µA, up to 20 h, 30° solid target configuration) of 70Zn targets (100-140 mg/cm2) electrodeposited onto silver via the 70Zn(p,α)67Cu nuclear reaction. Target work-up comprise a two- or three-step chromatographic column separation [1]. Gamma spectroscopy was used to quantify the radionuclidic purity (RNP), ICP-MS for the molar activity (Am) and test radiolabeling with the macrocyclic complexing agent TETA for apparent molar activity (AMA) quantification. Additionally, 67Ga was produced by proton irradiation (19 MeV, 35 µA, 2 h, 30° solid target configuration) of enriched 68Zn targets (60-70 mg/cm2) electrodeposited onto gold via the 68Zn(p,2n)67Ga nuclear reaction. After “cooling down” of the target (12-16 h, decay of co-produced 68Ga), the radiochemical separation consisted of a two-step chromatographic column separation; first a 1 mL TK400 cartridge followed by a 0.3 mL DGA branched cartridge. RNP was quantified by gamma spectroscopy.

Results: Activity yields of > 1.0 GBq 67Cu at EOB were reached, leading to over 800 MBq [67Cu]CuCl2 at EOP in 1.5 mL of 0.05 M HCl with RNP g.t. 99.5 % (at EOP) and AMA up to 300 GBq/µmol (EOB corrected). Furthermore, activities of up to 1.8 GBq 67Ga at EOB, and ca. 1.0 GBq [67Ga]GaCl3 at EOP in 0.5 mL of 0.05 M HCl were produced. First 67Ga gamma spectroscopy results showed a RNP of over 99 % at EOP. In both cases, the activity reached represented about 60 % to 70 % of the calculated yield.

Conclusions: Production of the radionuclides 67Cu and 67Ga from proton irradiation of zinc targets is being performed at HZDR. Both radionuclide product solutions proved sufficient quality regarding RNP and radiolabeling properties. further optimization of the 67Ga production is planned. Although 67Cu activities produced are not enough for clinical demand, the obtained yields are adequate for first in vitro and in vivo studies while other production routes are being explored.

References:

[1] Brühlmann SA, Walther M, Kreller M, Reissig F, Pietzsch H-J, Knieß T and Kopka K. Pharmaceuticals 2023, 16, 314.

  • Contribution to proceedings
    29. Jahrestagung der AGRR, 28.-30.09.2023, Bad Salzuflen, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-37410


Production of Lanthanum-133 via the134Ba(p,2n)133La Nuclear Reaction with High Radionuclide Purity for Theranostic Purposes

Brühlmann, S. A.; Kreller, M.; Pietzsch, H.-J.; Kopka, K.; Mamat, C.; Walther, M.; Reissig, F.

Aim/Introduction: Actinium-225 has gained great importance in Targeted Alpha Therapy (TAT) due to its suitable physical and chemical properties. In past years, studies using 225Ac-PSMA-617 have shown promising results [1], however, the macropa chelator has proven more beneficial properties regarding labelling and stability in vivo as compared with DOTA. While 68Ga has been used for DOTA-based radioconjugates, the macropa chelator lacks an imaging radionuclide counterpart. For this purpose, the β+-emitter 133La is an attractive candidate due to its physical properties and similar to 225Ac coordination chemistry. Following our recent publication [2], further optimization of the production of 133La with high radionuclidic purity (RNP) for theranostic purposes is presented. Materials and Methods: Lanthanum-133 was produced via the 134Ba(p,2n)133La nuclear reaction. Proton irradiation (19 MeV, 35 µA, 30 min) was performed using the HZDR TR-FLEX (ACSI) cyclotron on silver discs filled with 25 mg of [134Ba]BaCO3 capped with a 25 µm aluminum foil. The solid target was opened and the powder dissolved in 2 mL of 1 M HNO3. A one-step separation was carried out with a branched DGA resin cartridge after testing other resins. The 134Ba-containing fractions were collected and recycled through [134Ba]BaCO3 precipitation. Test radiolabelling of macropa-derived PSMA conjugates previously published by our group was performed in the MBq/nmol range [3]. Results: Lanthanum-133 yields of ca. 1.8 GBq for the described targets were reached at end of bombardment (EOB), accounting for about 65 % of the theoretical yield. After radiochemical separation, 1.2 GBq 133La were collected in 1 mL of 0.05 M HCl ready to label, with a RNP over 99.5 %. Further studies showed no detriment of the RNP by 21 MeV proton irradiation, thus being feasible irradiation of larger targets (prior thermal studies). Furthermore, quantitative radiolabeling was achieved with ligand concentrations down to 300 MBq/nmol. Conclusion: Lanthanum-133 of high RNP was produced for the first time. Considering future medical demands, the scale up to radioactivity amounts that are needed for clinical application purposes could be achieved by increasing the irradiation time. Alternatively, irradiation with higher currents or of thicker targets could also lead to higher activities. Based on these results, our group will attempt to establish a diagnostic platform for 225Ac-TAT based on 133La-macropa radioconjugates instead of the conventional 68Ga-DOTA application. References: [1] Kratochwil et al., J. Nucl. Med. 2016, 57, 1941-1944 [2] Brühlmann et al., Pharmaceuticals 2022, 15, 1167. [3] Reissig et al., Cancers 2021, 13, 1974.

  • Open Access Logo Contribution to proceedings
    EANM'23, 09.-13.09.2023, Wien, Austria

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Data publication: Multitask learning with convolutional neural networks and vision transformers can improve outcome prediction for head and neck cancer patients

Starke, S.; Zwanenburg, A.; Leger, K.; Lohaus, F.; Linge, A.; Schreiber, A.; Kalinauskaite, G.; Tinhofer, I.; Guberina, N.; Guberina, M.; Balermpas, P.; von der Grün, J.; Ganswindt, U.; Belka, C.; Peeken, J. C.; Combs, S. E.; Böke, S.; Zips, D.; Richter, C.; Troost, E. G. C.; Krause, M.; Baumann, M.; Löck, S.

This dataset contains the model checkpoints, predictions and performance metrics for the multitask neural networks presented in the corresponding manuscript.

Keywords: survival analysis; vision transformer; convolutional neural network; multitask learning; tumor segmentation; head and neck cancer; Cox proportional hazards; loco-regional control; progression-free survival; discrete-time survival models

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  • OncoRay

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Permalink: https://www.hzdr.de/publications/Publ-37408


Cyclotron-based production of the theranostic radionuclide 67Cu

Brühlmann, S. A.; Walther, M.; Kreller, M.; Reissig, F.; Pietzsch, H.-J.; Knieß, T.; Kopka, K.

Objectives
Copper-67 (half-life 61.83 h, β--emission [mean energy 140 keV], γ-emission [184.6 keV, 48.7 % intensity]), is a promising radiometal due to its theranostic potential. Moreover, it forms a perfect matched pair with the
β+-emitters 61Cu and 64Cu. However, broad application of this radionuclide is limited due to its low availability. In this work, we investigate the no-carrier-added 67Cu production via the 70Zn(p,α)67Cu reaction [1].

  • Contribution to proceedings
    10. Radiochemischer Workshop, 12.-14.06.2023, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-37407


Understanding electronic correlations in warm dense quantum plasmas

Dornheim, T.

Warm dense matter (WDM)---an extreme state that is characterized by extreme densities and temperatures---has emerged as one of the most active frontiers in plasma physics and material science. In nature, WDM occurs in astrophysical objects such as giant planet interiors and brown dwarfs. In addition, WDM is highly important for cutting-edge technological applications such as inertial confinement fusion and the discovery of novel materials. In the laboratory, WDM is studied experimentally in large facilities around the globe, and new techniques have facilitated unprecedented insights. Yet, the interpretation of these experiments requires a reliable diagnostics based on accurate theoretical modeling, which is a notoriously difficult task [1].

In this work, I will give an overview of how we can use exact ab-initio path integral Monte Carlo (PIMC) simulations [2] together with thermal density functional theory (DFT) calculations to get new insights into the behavior of WDM. This includes recent results for various density response properties [3] such as the exchange—correlation (XC) kernel [2,4], and the utility of PIMC reference data to assess the accuracy of different XC functionals [5].

Finally, I will show how switching to the imaginary-time representation allows us to significantly improve the interpretation of X-ray Thomson scattering (XRTS) experiments, which are a key diagnostic for WDM [3]. Specifically, I will present a model-free temperature diagnostic [6] based on the well-known principle of detailed balance, but available for all wave numbers, and a new idea to directly extract the electron—electron static structure factor from an XRTS measurement [7]. As an outlook, I will show how new PIMC capabilities [8] will allow to give us novel insights into electronic correlations in warm dense quantum plasmas, leading to unprecedented agreement between experiments [9] and theory.

[1] M. Bonitz et al., Physics of Plasmas 27, 042710 (2020)
[2] M. Böhme et al., Physical Review Letters 129, 066402 (2022)
[3] T. Dornheim et al., Physics of Plasmas 30, 032705 (2023)
[4] Zh. Moldabekov et al., Journal of Chemical Theory and Computation 19, 1286-1299 (2023)
[5] Zh. Moldabekov et al., arXiv:2308.07916 (submitted)
[6] T. Dornheim et al., Nature Communications 13, 7911 (2022)
[7] T. Dornheim et al., arXiv:2305.15305 (submitted)
[8] T. Dornheim et al., arXiv:2308.06071 (submitted)
[9] T. Döppner et al., Nature 618, 270-275 (2023)

  • Invited lecture (Conferences)
    CECAM Flagship Workshop: Accelerating Improvements in Density Functional Theory, 21.-25.08.2023, Lausanne, Schweiz

Permalink: https://www.hzdr.de/publications/Publ-37406


Cyclotron-based Production of Lanthanum-133 with High Radionuclide Purity for Theranostic Purposes

Brühlmann, S. A.; Kreller, M.; Pietzsch, H.-J.; Kopka, K.; Mamat, C.; Walther, M.; Reissig, F.

Objectives:

Targeted Alpha Therapy (TAT) is a research field of highest interest in specialized molecular radionuclide therapy. In particular, the radionuclide actinium-225 provides all necessary physical and chemical properties for a successful clinical application. Although the macropa chelator has shown beneficial properties regarding labelling and stability in vivo as compared with DOTA, the former lacks an imaging radionuclide counterpart to 225Ac. In this connection, lanthanum is an appropriate surrogate for actinium due to its comparable coordination chemistry. Furthermore, the imaging properties of the β+-emitter lanthanum-133 makes it an attractive candidate as a theranostic matched pair to 225Ac. Following our recent publication [1], 133La of high radionuclide purity for theranostic purposes was produced through the 134Ba(p,2n)133La reaction.

  • Open Access Logo Contribution to proceedings
    25th International Symposium in Radiopharmaceutical Sciences, 22.-26.05.2023, Honolulu, USA

Permalink: https://www.hzdr.de/publications/Publ-37405


Cyclotron Production of Copper-67: Exploring the limits

Brühlmann, S. A.; Walther, M.; Kreller, M.; Reissig, F.; Pietzsch, H.-J.; Knieß, T.; Kopka, K.

Objectives.
Copper-67 (67Cu, half-life 61.83 h, β--emission [mean energy 140 keV], γ-emission [184.6 keV with 48.7 % intensity, i.a.]), is a promising radiometal due to its theranostic potential. While 61Cu and 64Cu are suitable for PET, matched pair 67Cu brings a therapeutic counterpart to the table. However, broad application of this radionuclide is limited due to its low availability. No-carrier-added 67Cu can be produced through the 70Zn(p,α)67Cu reaction, while featuring a low yield and the need of expensive 70Zn target material. Nevertheless, co-production of other copper nuclides (from other zinc isotopes low-content) as well as contamination with stable copper can be minimized but not completely eliminated.

  • Open Access Logo Contribution to proceedings
    25th International Symposium in Radiopharmaceutical Sciences, 22.-26.05.2023, Honolulu, USA

Permalink: https://www.hzdr.de/publications/Publ-37404


Guidance for measuring the axial gas dispersion coefficient in bubble columns via gas flow modulation

Marchini, S.; Bieberle, A.; Schubert, M.; Hampel, U.

The gas flow modulation technique (GFM) is a novel non-invasive approach for measuring the axial gas dispersion coefficient in bubble columns. The approach overcomes the limitations of traditional tracer-based techniques, qualifying it as a promising candidate for measurements in an industrial setting. The current work elaborates systematic guidelines for selecting the experimental parameters for the GFM. These guidelines are crucial for its successful application. In addition, a novel approach is proposed for confidently extracting the values and the uncertainty limits of the axial gas dispersion coefficient. Afterwards, we show the application of these guidelines in the frame of a case study that serves the purpose to illustrate their application and to demonstrate their usefulness.

Keywords: gas flow modulation; axial dispersion coefficient; bubble columns; gas flow modulation workflow

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Permalink: https://www.hzdr.de/publications/Publ-37403


Unravelling the nonlinear ideal density response of many-body systems

Tolias, P.; Dornheim, T.; Moldabekov, Z.; Vorberger, J.

Nonlinear density response theory is revisited focusing on the harmonically perturbed finite temperature uniform electron gas. Within the non-interacting limit, brute force quantum kinetic theory calculations for the quadratic, cubic, quartic and quintic responses reveal a deep connection with the linear response. Careful analysis of the static long wavelength limit led us to conjecture a canonical non-interacting form that expresses arbitrary order nonlinear responses as the weighted sum of the linear responses evaluated at all multiple harmonics. This harmonic expansion is successfully validated against ab initio path integral Monte Carlo simulations.

Permalink: https://www.hzdr.de/publications/Publ-37402


Schätze im Müll

Matys, S.

Anhand des Beispiels Mobiltelefon wird erklärt, wie viele wertvolle Rohstoffe in elektronischen Geräten stecken und wie die Forschenden am HIF mit der Etablierung neuer (bio)technologischer Methoden dazu beitragen, dem Ziel einer geschlossenen Kreislaufwirtschaft näher zu kommen.

Keywords: Biotechnologie; Kreislaufwirtschaft; Wertstoffe; Metalle

  • Lecture (others)
    Abschlussveranstaltung Mathematikolympiade 2023 Landkreis Bautzen, 26.02.2023, Radeberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-37401


Asphericity derived from [18F]FDG PET as a new prognostic parameter in cervical cancer patients

Cegla, P.; Hofheinz, F.; Burchardt, E.; Czepczyński, R.; Kubiak, A.; van den Hoff, J.; Nikulin, P.; Bos-Liedke, A.; Roszak, A.; Cholewinski, W.

The objective of this study was to assess the prognostic value of asphericity (ASP) and standardized uptake ratio (SUR) in cervical cancer patients. Retrospective analysis was performed on a group of 508 (aged 55 ± 12 years) previously untreated cervical cancer patients. All patients underwent a pretreatment [18F]FDG PET/CT study to assess the severity of the disease. The metabolic tumor volume (MTV) of the cervical cancer was delineated with an adaptive threshold method. For the resulting ROIs the maximum standardized uptake value (SUVmax) was measured. In addition, ASP and SUR were determined as previously described. Univariate Cox regression and Kaplan–Meier analysis with respect to event free survival (EFS), overall survival (OS), freedom from distant metastasis (FFDM) and locoregional control (LRC) was performed. Additionally, a multivariate Cox regression including clinically relevant parameters was performed. In the survival analysis, MTV and ASP were shown to be prognostic factors for all investigated endpoints. Tumor metabolism quantified with the SUVmax was not prognostic for any of the endpoints (p > 0.2). The SUR did not reach statistical significance either (p = 0.1, 0.25, 0.066, 0.053, respectively). In the multivariate analysis, the ASP remained a significant factor for EFS and LRC, while MTV was a significant factor for FFDM, indicating their independent prognostic value for the respective endpoints. The alternative parameter ASP has the potential to improve the prognostic value of [18F]FDG PET/CT for event-free survival and locoregional control in radically treated cervical cancer patients.

Keywords: NA

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  • PET-Center

Permalink: https://www.hzdr.de/publications/Publ-37400


Multi-sensor spectral database of WEEE polymers

de Lima Ribeiro, A.; Fuchs, M.; Lorenz, S.; Röder, C.; Heitmann, J.; Gloaguen, R.
DataCollector: Madriz, Yuleika; DataCollector: Herrmann, Erik

Polymers represent around 25% of total waste from electronic and electric equipment. Any successful recycling process must ensure that polymer-specific functionalities are preserved, to avoid downcycling. This requires a precise characterization of particle compounds moving at high speeds on conveyor belts in processing plants. We present a multi-sensor database including spectra acquired from imaging and point measurement sensors on 23 polymers including ABS, PS, PC, PE-types, PP, PVC, PET-types, PMMA, and PTFE. The techniques applied include hyperspectral imaging sensors (HSI) to map reflectance in the visible to near infrared (VNIR, (350–1000) nm ), short-wave (SWIR, (1000–2500) nm) and mid-wave infrared (MWIR, (2500–5000) nm) as well as point Raman, FTIR and portable spectral spectroradiometer (PSR) instruments.

Keywords: plastics; e-waste; hyperspectral; Raman

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Permalink: https://www.hzdr.de/publications/Publ-37399


Coupled 3D neutronics/thermal-hydraulics analysis of Superphénix start-up tests with DYN3D/ATHLET code system

Ponomarev, A.; Nikitin, E.; Fridman, E.

The capabilities of the DYN3D/ATHLET coupled code system were recently extended to allow for 3D neutron kinetics/thermal hydraulics analyses of Sodium cooled Fast Reactors at reactor system level. In this paper, the DYN3D/ATHLET coupled code system was applied to analyze the Superphenix reactor transient benchmark. The benchmark comprises six operational transients initiated during the SPX reactor start-up tests, covering a wide range of reactor operating states. The peculiarity of these transients is the necessity to consider thermal expansions of major structural elements of the primary system, which significantly influence the transient position of control rods in the core. The paper includes a brief summary of the benchmark specifications, description of the neutron kinetics and thermal hydraulics models, an analysis of the simulation results, and a comparison to the experimental data.

Keywords: ATHLET; DYN3D; Monte Carlo; Serpent; SFR; Superphenix; Thermal hydraulics analysis; Control rods

Permalink: https://www.hzdr.de/publications/Publ-37397


Strömungstechnischer Funktionsnachweis für Verschlussbauwerke und flüssigkeitsgestützte Abdichtung des Kontaktbereiches Phase III (Vertiefung Kenntnisstand Kontaktbereich & Injektionsmittel, in situ-Versuche) (STROEFUN III) Schlussbericht (Hauptband)

Bauermeister, J.; Langefeld, O.; Schieweg, A.; Raebiger, L.; Abel, P.; Viertel, T.; Flemming, J.; Noorhan, W.; Ley, S.; Glaubach, U.; Wilsnack, T.; Müller-Hoeppe, N.; Hussein, A.; Fischer, T.; Lack, D.; Schicht, T.; Brüning, M.; Kulenkampff, J.

In dem Forschungsvorhaben STROEFUN III wurde ein Konzept für die strömungstechnische Testung von Streckenverschlussbauwerken entwickelt, installiert und in einem Streckenver-schlussbauwerk in der Grube Teutschenthal erfolgreich getestet. Das Testkonzept für Bauwerke oder Bauwerksabschnitte aus hydraulisch abbindenden Dichtbaustoffen basiert auf der Druckbeaufschlagung von mindestens 3 an der Streckenkontur installierten Ringkammern. Diese können individuell mit Gas und/oder Flüssigkeit im stationären oder instationären Druck-regime beaufschlagt werden. Das Konzept konzentriert sich auf die Testung des Kontaktbereiches Baustoff/ Gebirge als bestimmenden Strömungsraum für die Dichtwirkung von Stre-ckenverschlussbauwerken. Im Ergebnis der modellbasierten Auswertung der im Test ermittelten Druckganglinien sind Aussagen über die Permeabilität des Bauwerkes im Kontakt Bau-stoff/ Gebirge und, daraus abgeleitet, für die integrale Permeabilität des Bauwerkes möglich. Das Testkonzept ist ein zusätzlicher Baustein für den gegenständlichen, strömungstechni-schen Funktionstest von Streckenverschlussbauwerken im Rahmen der Nachweisführung. Im Ergebnis des Forschungsvorhabens liegen umfangreiche Kenntnisse zum Standort und zum Bauwerk aus MgO-Baustoff (angelehnt an die A1-Basisrezeptur) vor. Dieser umfangreiche Kenntnisstand, die Zugänglichkeit und die Standortbedingungen bieten die Chance in der nahen Zukunft eine Vielzahl an Untersuchungen zur nachträglichen Vergütung des Bauwerkes mit Beurteilung der strömungstechnischen Wirkung der Vergütung sowie zum zeitabhängigen Baustoffverhalten im Kontakt zur Atmosphäre und im Kontakt zur Salzlösung durchzuführen.

In the research project STROEFUN III a concept for the fluidic testing of closuring structures was developed, installed and successfully tested on a closuring structure at the Teutschenthal mine. The test concept for structures or sections of structures made of hydraulically settling sealing materials is based on the pressurization of at least 3 ring chambers installed on the drift contour. These can be individually pressurized with gas and/or liquid in a steady-state or transient pressure regime. The concept concentrates on testing the contact area between material and rock mass as the determining flow space for the sealing effect of drift closure structures. As a result of the modelbased evaluation of the pressure hydrographs determined in the test, statements can be made about the permeability of the structure in the contact between the building material and the rock mass and, derived from this, about the integral permeability of the structure. The test concept is an additional option for the fluidic functional test of drifts closure structures within the scope of verification of sealing effect. As a result of the research project, extensive knowledge is available on the location and the structure made of MgO-building material. This extensive knowledge, the accessibility and the site conditions offer the opportunity in the near future to carry out a large number of investigations on the subsequent improvement of the structure with assessment of the fluidic effect of the improvement as well as on the time-dependent behavior of the building material in contact with the atmosphere and in contact with the salt solution.

Keywords: underground repository; underground dam sealing; MgO concrete; closure structure; µCT

Permalink: https://www.hzdr.de/publications/Publ-37396


Timing and origin of skarn-, greisen-, and vein-hosted tin mineralization at Geyer, Erzgebirge (Germany)

Meyer, N.; Markl, G.; Gerdes, A.; Gutzmer, J.; Burisch, M.

This contribution presents new insights into the origin and age relationships of the Geyer tin deposit in the Erzgebirge, Germany. Tin mineralization occurs in skarns, greisen, and in cassiterite-bearing fluorite-quartz veins. Skarn alteration replaces marble layers of the Cambrian Jáchymov Group and occurs in two clearly distinct stages. The first skarn stage forms skarnoid textured assemblages of clinopyroxene, garnet, and wollastonite with no tin phases recognized. Garnet U-Pb ages of this skarn stage (~322 Ma) relate the earlier skarn stage to the emplacement of the Ehrenfriedersdorf granite (~324 to 317 Ma). The second stage of skarn alteration is marked by the occurrence of malayaite and cassiterite associated with garnet recording ages of 307 to 301 Ma. Greisen- and skarn-hosted cassiterite-bearing veins provide U-Pb ages in the range of 308 to 305 Ma, relating greisenization and vein formation to the same magmatic-hydrothermal event as the second skarn stage. This suggests that tin mineralization at Geyer is related to a distinctly younger magmatic-hydrothermal event, clearly postdating the Ehrenfriedersdorf granite, which was previously assumed as the source of the tin-rich fluids. Fluid inclusions show salinities in the range of 1.0 to 31.5 % eq. w(NaCl±CaCl2) and homogenization temperatures between 255 and 340 °C. Cassiterite-associated fluid inclusions show indications for heterogeneous entrapment and dilution of hydrothermal with meteoric fluids. Dilution of high-salinity fluids with low-salinity fluids and cooling of the system was probably a decisive process in the precipitation of cassiterite in the Geyer Sn system.

Keywords: Erzgebirge; skarn; greisen; tin

Permalink: https://www.hzdr.de/publications/Publ-37395


Ion-induced telecom single-photon emitters in silicon

Astakhov, G.; Hollenbach, M.; Klingner, N.; Jagtap, N.; Bischoff, L.; Fowley, C.; Kentsch, U.; Hlawacek, G.; Erbe, A.; Abrosimov, N. V.; Helm, M.; Berencen, Y.

Single-photon emitters (SPEs) are one of the elementary building blocks for photonic quantum information and optical quantum computing. One of the upcoming challenges is the monolithic photonic integration and coupling of single-photon emission, reconfigurable photonic elements, and single-photon detection on a silicon chip in a controllable manner. Particularly, fully integrated SPEs on-demand are required for enabling a smart integration of advanced functionalities in on-chip quantum photonic circuits. The major challenge in realizing a fully monolithic, photonic integrated circuitry lies in the development of a quantum light source in silicon since the indirect nature of the small energy bandgap does not allow for efficient PL emission. Nevertheless, below-bandgap light emission can be used for good advantage by exploiting extrinsic and intrinsic point defects acting as SPEs. Indeed, the isolation of SPEs, such as G-, W-, and T-centers, in the optical telecommunication O-band has been recently realized in silicon.. In all these cases, however, SPEs were created uncontrollably in random locations, preventing their scalability.
We present mask-free nanofabrication involving a quasi-deterministic creation of single G- and W-centers in silicon wafers using focused-ion beam (FIB) writing. We also implement a scalable, broad-beam implantation protocol compatible with the complementary-metal-oxide-semiconductor (CMOS) technology to fabricate telecom SPEs at desired positions on the nanoscale.

Keywords: Quantum technologies; Single photon emitters; Silicon; Defects

Involved research facilities

Related publications

  • Invited lecture (Conferences)
    25th International Conference on the Electronic Properties of Two-Dimensional Systems (EP2DS-25) and 21st International Conference on Modulated Semiconductor Structures (MSS-21), 10.-14.07.2023, Grenoble, France

Permalink: https://www.hzdr.de/publications/Publ-37394


Hybrid quantum technologies with spin qubits in SiC

Astakhov, G.

An overview of quantum technologies based on spin defects in SiC is presented. It includes microwave assisted spectroscopy, inverted excited-state structure for spin-photon entanglement protocols and acoustic control of spin qubits.

Keywords: Quantum technologies; Spin qubits; Silicon carbide; Defects

Involved research facilities

Related publications

  • Invited lecture (Conferences)
    Seminar at the Institute of Applied Quantum Technologies, 09.02.2023, Erlangen, Germany

Permalink: https://www.hzdr.de/publications/Publ-37393


18F-FDG PET/CT-derived total lesion glycolysis predicts abscess formation in patients with surgically confirmed infective endocarditis: Results of a retrospective study at a tertiary center

Maria Sag, S. J.; Menhart, K.; Hitzenbichler, F.; Schmid, C.; Hofheinz, F.; van den Hoff, J.; Maier, L. S.; Hellwig, D.; Grosse, J.; Sag, C. M.

Background
Abnormal activity of 18F-FDG PET/CT is a major Duke criterion in the diagnostic work-up of infective prosthetic valve endocarditis (IE). We hypothesized that quantitative lesion assessment by 18F-FDG PET/CT-derived standard maximum uptake ratio (SURmax), metabolic volume (MV), and total lesion glycolysis (TLG) might be useful in distinct subgroups of IE patients (e.g. IE-related abscess formation).

Methods
All patients (n = 27) hospitalized in our tertiary IE referral medical center from January 2014 to October 2018 with preoperatively performed 18F-FDG PET/CT and surgically confirmed IE were included into this retrospective analysis.

Results
Patients with surgically confirmed abscess formation (n = 10) had significantly increased MV (by ~ fivefold) and TLG (by ~ sevenfold) as compared to patients without abscess (n = 17). Receiver operation characteristics (ROC) analyses demonstrated that TLG (calculated as MV × SURmean, i.e. TLG (SUR)) had the most favorable area under the ROC curve (0.841 [CI 0.659 to 1.000]) in predicting IE-related abscess formation. This resulted in a sensitivity of 80% and a specificity of 88% at a cut-off value of 14.14 mL for TLG (SUR).

Conclusion
We suggest that 18F-FDG PET/CT-derived quantitative assessment of TLG (SUR) may provide a novel diagnostic tool in predicting endocarditis-associated abscess formation.

Keywords: 18F-FDG PET/CT; infective endocarditis; total lesion glycolysis; valve abscess

Involved research facilities

  • PET-Center

Permalink: https://www.hzdr.de/publications/Publ-37392


Numerical Simulations of the Pore-Scale Flow in Ceramic Open-Cell Foams

Hernandez, J. N. C.; Schubert, M.; Hampel, U.

Porous materials are abundant in nature and in industrial applications. Their ability to allow fluids passing through them is of major importance and plays a very important role in various operations, such as hydrocarbon extraction of reservoirs in oil production [1]; or by dictating the amount of heat that can be dissipated from an electronic component using force convection (e.g. heat sinks) [2]. The key indicator of how easily fluids pass through porous materials is the “permeability”, which allows describing pressure loss and flow velocity in porous materials. However, the impact of droplet impingement inside open-cell foams and the retention time of a solid or liquid disperse phase cannot be described solely by the permeability. To study these phenomena current computing resources permit pore-scale CFD simulations, which relate structure and transport properties of porous materials. Instead of using equivalent geometrical models based on simple geometries just as spheres or cylinders, the genuine geometry representation of the porous structure is required, especially since porous media usually involve significant pore structure defects and feature multiple length scales, which produce different mechanisms of interaction within the pores.
The present work investigates the performance of pore-scale numerical simulations over genuine 3D geometrical representations of ceramic foams reconstructed from X-ray micro-computed tomography (μCT) scans of silicon-infiltrated silicon carbide” (SiSiC) open-cell foams with different nominal pore sizes using marching cubes algorithm [3]. To disclose the airflow velocity profile inside the foam simulations of single-phase air flow were conducted using finite volume method (FVM) for a wide range of Reynolds numbers including Reynolds-averaged Navier-Stokes (RANS) turbulence models. Good agreement was achieved especially between the computed pressure gradient and the experimental pressure measurements, even outperforming other conventional numerical models based on average pore properties such as porosity and surface area. Further simulations were carried out using a Lagrangian approach to analyze particular effects such as rebounding of a low mass fraction of the disperse phase on the ceramic structure and deposition thresholds.
The work already done pursues to improve upon the current state-of-the-art of pore-scale simulations, providing evidence of the feasibility to perform flow simulations on reconstructed representations of ceramic porous media that considerably are able to predict experimental flow properties.

Involved research facilities

  • TOPFLOW Facility
  • Poster
    4th World Congress on Momentum, Heat and Mass Transfer (MHMT'19), 10.-12.04.2019, Rome, Italy
    DOI: 10.11159/icmfht19.124

Permalink: https://www.hzdr.de/publications/Publ-37391


Microwave Dielectric Properties of Open-Cell Solid Foams Based on Silicon Carbide Ceramics

Hernandez, J. N. C.; Sodatov, S.; Link, G.; Füssel, A.; Hampel, U.

Open-cell porous materials are abundant in industrial applications and are used for example as heat exchangers, thermal insulators, reaction catalysts, flow stabilizers, mass transfer enhancers, solar radiation absorbers and electrical heaters, etc. [1]. In recent years, the interest in solid foams based on silicon carbide “SiC” has regained popularity. Nevertheless, when applied to microwave applications there is a lack of reported properties. The key indicator of how a material interacts and is heated with microwaves is the “permittivity”, which is best described in a complex form. The aim of this work is to improve the database of complex permittivity of open-cell solid foams based on silicon carbide, which was determined using the cavity perturbation method [2]. Temperature dependent measurements of permittivity were performed in the range of 30 °C to 190 °C for three different foam materials, i.e. silicon infiltrated silicon carbide (SiSiC), pressureless sintered silicon carbide (SSiC) and silicate-bounded silicon carbide (SBSiC), with porosities in the range of 86.9 % to 96.5 % and pore size of 30 ppi (pore per inch), 45 ppi and 60 ppi. As a result, a model based on mixture rules was developed that well predicts the permittivity as a function of porosity.

Keywords: microwaves; complex permittivity; SiC; open-cell solid foams

Involved research facilities

  • TOPFLOW Facility
  • Lecture (Conference)
    17th International Conference on Microwave and High Frequency Heating AMPERE 2019, 09.-12.6.2019, Valencia, Spain

Permalink: https://www.hzdr.de/publications/Publ-37390


Extending the coherence of spin defects in hBN enables advanced qubit control and quantum sensing

Rizzato, R.; Schalk, M.; Mohr, S.; Hermann, J. C.; Leibold, J. P.; Bruckmaier, F.; Salvitti, G.; Ji, P.; Astakhov, G.; Kentsch, U.; Helm, M.; Stier, A. V.; Finley, J. J.; Bucher, D. B.

Negatively-charged boron vacancy centers hexagonal Boron Nitride (hBN) are attracting increasing interest since they represent optically-addressable qubits in a van der Waals material. In particular, these spin defects have shown promise as sensors of temperature, pressure, and static magnetic fields. However, their short spin coherence time limits their scope for quantum technology. Here, we apply dynamical decoupling techniques to suppress magnetic noise and extend the spin coherence time by two orders of magnitude, approaching the fundamental T1 relaxation limit. Based on this improvement, we demonstrate advanced spin control and a set of quantum sensing protocols to detect electromagnetic signals in the MHz range with sub-Hz resolution. This work lays the foundation for nanoscale sensing using spin defects in an exfoliable material and opens a promising path to quantum sensors and quantum networks integrated into ultra-thin structures.

Keywords: Quantum technologies; 2D materials; Spintronics; Defects

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-37389


Multitask Learning with Convolutional Neural Networks and Vision Transformers Can Improve Outcome Prediction for Head and Neck Cancer Patients

Starke, S.; Zwanenburg, A.; Leger, K.; Lohaus, F.; Linge, A.; Schreiber, A.; Kalinauskaite, G.; Tinhofer, I.; Guberina, N.; Guberina, M.; Balermpas, P.; von der Grün, J.; Ganswindt, U.; Belka, C.; Peeken, J. C.; Combs, S. E.; Böke, S.; Zips, D.; Richter, C.; Troost, E. G. C.; Krause, M.; Baumann, M.; Löck, S.

Neural-network-based outcome predictions may enable further treatment personalization of patients
with head and neck cancer. The development of neural networks can prove challenging when a limited number of cases is available. Therefore, we investigated whether multitask learning strategies, implemented through the simultaneous optimization of two distinct outcome objectives (multi-outcome) and combined with a tumor segmentation task, can lead to improved performance of convolutional neural networks (CNN) and vision transformers (ViT). Model training was conducted on two distinct multicenter datasets for the endpoints loco-regional control (LRC) and progression-free survival (PFS), respectively. The first dataset consisted of pre-treatment computed tomography (CT) imaging for 290 patients and the second dataset contained combined positron emission tomography (PET)/CT for 224 patients. Discriminative performance was assessed by the concordance index (C-index). Risk stratification was evaluated using log-rank tests. Across both datasets, CNN and ViT model ensembles achieved similar results. Multitask approaches showed favorable performance in most investigations. Multi-outcome CNN models trained with segmentation loss were identified as the optimal strategy across cohorts. On the PET/CT dataset, an ensemble of multi-outcome CNNs trained with segmentation loss achieved the best discrimination (C-index: 0.29, 95% confidence interval (CI): 0.22-0.36) and successfully stratified patients into groups with low and high risk of disease progression (p=0.003). On the CT dataset, ensembles of multi-outcome CNNs and of single-outcome ViTs trained with segmentation loss performed best (C-index: 0.26 and 0.26, CI: 0.18-0.34 and 0.18-0.35, respectively), both with significant risk stratification for LRC in independent validation (p=0.002 and p=0.011). Further validation of the developed multitask-learning models is planned based on a prospective validation study, which is currently ongoing.

Keywords: survival analysis; vision transformer; convolutional neural network; multitask learning; tumor segmentation; head and neck cancer; Cox proportional hazards; loco-regional control; progression-free survival; discrete-time survival models

Involved research facilities

  • OncoRay

Related publications

Permalink: https://www.hzdr.de/publications/Publ-37388


Plasmas, fluids and lasers

Nikl, J.

Plasma is the most abundant form of matter in our universe. Fluid dynamics then presents one of the most successful models of modern physics and lasers are the most versatile tools of the 21st century. All these topics are introduced and their joint applications at HZDR and elsewhere are presented.

  • Lecture (others)
    HZDR summer school, 31.07.-31.08.2023, HZDR Campus, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-37387


Orientation resolved measurements of accelerations with sensor particles in bioreactors

Buntkiel, L.; Ma, Y.; Reinecke, S.; Hampel, U.

The measurement of the spatially distributed
flow field in large industrial vessels, e.g. biogas fermenters,
is not possible with commercially available measurement
equipment. Therefore the concept of flow following sensor
particles has been developed. They act as data loggers
within the vessel. The sensor particles are equipped with
a pressure sensor and an inertial measurement unit to
measure their motion. The measurements are taken in
the coordinate frame of the sensor particle and need to
be transformed into the vessel’s coordinate frame to ana-
lyze the flow field. This is done by an error-state Kalman
filter which estimates the orientation of the sensor par-
ticle with respect to the vessel based on the direction
of the gravitational acceleration and the local magnetic
field. Since no other aiding sensors are available or usable
within an industrial vessel particular emphasis was given
to the stochastic modeling of the inertial sensors and the
calibration of the accelerometer. Based on the orienta-
tion estimation, the measured acceleration is transformed
into the vessel frame. We performed two experiments in
a 1.4 m³ lab reactor to qualify this approach. The results
show, that the transformed acceleration is in good quali-
tative agreement with the known flow field inside the lab
reactor

Keywords: Sensor particle; Flow follower; Flow measurement; Kalman filter; Inertial measurements

Downloads

  • Secondary publication expected from 16.11.2024

Permalink: https://www.hzdr.de/publications/Publ-37386


Ultra-high dose rate radiobiology with protons at the DRACO and PENELOPE high power laser facilities

Metzkes-Ng, J.

Ultra-high dose rate radiobiology with protons at the DRACO and PENELOPE high power laser facilities

Involved research facilities

  • ATHENA
  • OncoRay
  • Draco
  • Invited lecture (Conferences)
    Very High Energy Electron Radiotherapy Conference 2023, 10.-13.07.2023, Hamburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-37385


Fermionic physics from ab initio path integral Monte Carlo simulations of fictitious identical particles

Dornheim, T.; Tolias, P.; Groth, S.; Moldabekov, Z.; Vorberger, J.; Hirshberg, B.

The \emph{ab initio} path integral Monte Carlo (PIMC) method is one of the most successful methods in statistical physics, quantum chemistry and related fields, but its application to quantum degenerate Fermi systems is severely hampered by an exponential computational bottleneck: the notorious fermion sign problem. Very recently, Xiong and Xiong [J. Chem. Phys. 157, 094112 (2022)] have suggested to partially circumvent the sign problem by carrying out PIMC simulations of fictitious systems which contain an interpolating continuous variable ξ∈[−1,1] in their partition function, with the physical Fermi- and Bose-statistics corresponding to the endpoint limits ξ=−1 and ξ=1. It has been proposed that thermodynamic information about the fermionic limit might be obtained by path integral calculations within the bosonic sector ξ>0 combined with a quadratic ξ extrapolation throughout the fermionic sector ξ<0, essentially bypassing the sign problem. In this work, we show how the inclusion of the artificial parameter ξ can be interpreted as an effective penalty on the formation of permutation cycles in the PIMC simulation. We empirically demonstrate that the proposed extrapolation method breaks down for moderate to high quantum degeneracy. Instead, the method constitutes a valuable tool for the description of large Fermi-systems of weak quantum degeneracy. This is demonstrated for electrons in a 2D harmonic trap and for the archetypal uniform electron gas (UEG), where we find excellent agreement (∼0.5%) with exact configuration PIMC results in the high-density regime while attaining a speed-up exceeding eleven orders of magnitude. Finally, we extend the idea beyond the energy and analyze the radial density distribution (2D trap), as well as the static structure factor and imaginary-time density-density correlation function (UEG).

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Permalink: https://www.hzdr.de/publications/Publ-37382


Simultaneous inhibition of discoidin domain receptor 1 and integrin αVβ3 radiosensitizes human glioblastoma cells

Elser, M.; Vehlow, A.; Juratli, T.; Cordes, N.

Glioblastomas (GBM) are the most common primary brain tumors in adults and associated with poor clinical outcomes due to therapy resistances and destructive growth. Interactions of cancer cells with the extracellular matrix (ECM) play a pivotal role in therapy resistances and tumor progression. In this study, we investigate the functional dependencies between the discoidin domain receptor 1 (DDR1) and the integrin family of cell adhesion molecules for the radioresponse of human glioblastoma cells. By means of an RNA interference screen on DDR1 and all known integrin subunits, we identified co-targeting of DDR1/integrin β3 to most efficiently reduce clonogenicity, enhance cellular radiosensitivity and diminish repair of DNA double strand breaks (DSB). Simultaneous pharmacological inhibition of DDR1 with DDR1-IN-1 and of integrins αVβ3/αVβ5 with cilengitide resulted in confirmatory data in a panel of 2D grown glioblastoma cultures and 3D gliospheres. Mechanistically, we found that key DNA repair proteins ATM and DNA-PK are altered upon DDR1/ integrin αVβ3 /integrin αVβ5 inhibition, suggesting a link to DNA repair mechanisms. In sum, the radioresistance of human glioblastoma cells can effectively be declined by co-deactivation of DDR1, integrin αVβ3 and integrin αVβ5.

Keywords: GBM; Integrins; Radiotherapy; DDR1

  • Open Access Logo American Journal of Cancer Research 13(2023)10, 4597-4612

Permalink: https://www.hzdr.de/publications/Publ-37381


Strong magnetoelastic coupling in MnCoSi compounds studied in pulsed magnetic fields

Zhang, F.; Bykov, E.; Gottschall, T.; van Dijk, N.; Brück, E.

The orthorhombic MnCoSi compounds have been found to present a large magnetoelastic coupling, which is regarded as the source for the magnetocaloric effect (MCE) and the magnetostrictive effect. As a result, these compounds are potential materials for caloric applications such as solid-state refrigeration. In the presentstudy, we offer fundamental insights in the magnetoelastic coupling in these compounds based on their structural, metamagnetic, and MCE behavior. The directly measured adiabatic temperature change (ΔTad) in different initial temperatures (down to 18 K) and pulsed magnetic fields (up to 40 T) presents a moderate MCE performance (the maximum ΔTad = –3.1 K for a field change of 13 T), which results from the metamagnetic behavior of these compounds. Furthermore, the magnetization measurements in pulsed (and static) magnetic fields indicate that the magnetoelastic coupling is significantly enhanced for increasing fields resulting in an improved saturation magnetization. The metamagnetic transition is continuously pushed to lower temperatures in higher fields. The phase diagram constructed from the experimental transition temperatures Tt and the critical magnetic fields μ0Hcr indicate that the transition is terminated below 18 K and that ferromagnetism is stabilized for fields above 22.3 T. Our results provide unique insights into the strong magnetoelastic coupling under high pulsed magnetic fields, providing guidelines for the design of giant magnetocaloric materials for future caloric applications.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-37380


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