Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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41396 Publications

Segregation Channel Dynamics in Directionally Solidifying Ga-In Alloy with and without a Magnetic Field

Shevchenko, N.; Kao, A.; Fan, X.; Tonry, C.; Atwood, R.; Lee, P.; Pericleous, K.; Eckert, S.

The formation of freckle defects in the presence of an external magnetic field is studied by combining *in situ* synchrotron imaging with numerical simulations. The formation, growth and motion of freckle channels during directional solidification are investigated in a Hele-Shaw cell for a low melting point Ga-In alloy. The solidification cell is placed in a permanent magnet system providing a flux density of about 120 mT within the cell. A parallel numerical study, using a microscopic parallelized Cellular Automata lattice Boltzmann method, is validated by these *in situ* experiments. An excellent match between the numerical model and experiments conducted on thin rectangle sample alloy is achieved. Evaluation of the *in situ* X-ray data and numerical analysis shows the role of thermoelectric magnetohydrodynamics (TEMHD) and electromagnetic damping (EMD) in the formation of channels and ultimately freckle defects. The channel motion can be attributed to the thermoelectric Lorentz force acting on the inter-dendritic liquid flow by causing the solute to accumulate at one side of the cell. *In situ* synchrotron experiments allow us to resolve the complex channel dynamics and simultaneously show how large-scale flow fields may alter it. Both temperature gradient and grain orientation can affect the dynamics of the segregation channels formation in the presence of the magnetic field. The effect of electromagnetic damping force to convective transport needs future investigations. The *in situ* synchrotron data and numerical modelling will provide further understanding of the underlying mechanisms and identifying further interesting phenomena.

Keywords: Solidification; Melt flow; Segregation channels; Magnetic fields; Ga-In alloy

  • Lecture (Conference) (Online presentation)
    European Congress and Exhibition on Advanced Materials and Processes - EUROMAT 2021, 12.-16.09.2021, Web-conference, Virtual

Permalink: https://www.hzdr.de/publications/Publ-33752
Publ.-Id: 33752


Influence of substitutions and hydrogenation on the structural and magnetic properties of (R’R’’)2Fe17 (R’, R’’ = Sm, Er, Ho): Compositions with promising fundamental characteristics

Tereshina, I. S.; Veselova, S. V.; Verbetsky, V. N.; Paukov, M. A.; Gorbunov, D.; Tereshina-Chitrova, E. A.

The structural and magnetic properties of the (R,R’)2Fe17-type (R and R’ are heavy (Ho, Er) and light (Sm) rare earth metals, respectively) compounds and the (R,R’)2Fe17Hy hydrides are reported. The hydrides with a high hydrogen concentration (y ≥ 4) are obtained by direct hydrogen absorption by the intermetallics. The rhombohedral Th2Zn17-type of structure is inherent in the Sm containing parent compounds and hydrides. The unit cell increase and increased Curie temperature are characteristic of the hydrides. Magnetic properties of the samples are investigated in pulsed magnetic fields up to 60 T. Strong magnetic fields induce phase transitions in the compounds with a high content of heavy rare earth elements. The parameter of the intersublattice exchange interaction is estimated.

Permalink: https://www.hzdr.de/publications/Publ-33751
Publ.-Id: 33751


Feasibility of using contactless electromagnetic cavitation for steel composite manufacturing

Sarma, M.; Grants, I.; Herrmannsdörfer, T.; Gerbeth, G.

This work investigates the feasibility of using contactless electromagnetic sonication for dispersing and refining a strengthening phase in iron and steel for ferrous metal matrix composite (MMCs) production. An oscillating pressure field is generated using superposition of alternating (0.13 T) and steady magnetic fields (up to 8 T). The processing employs a static floating-zone technique and is crucible-free. This approach allows to reach around 0.8 MPa pressure oscillation amplitude that is sufficient to initiate acoustic cavitation in high melting temperature liquid metals. The viability of various reinforcement dispersion, both ex and in situ, using this electromagnetic sonication is explored in the context of oxide dispersion strengthened (ODS) steel and high modulus steel (HMS) production.

Keywords: contactless cavitation; solidification processing; steel composites

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Permalink: https://www.hzdr.de/publications/Publ-33750
Publ.-Id: 33750


Understanding the role of magnetic fields on freckle formation during solidification through in situ imaging

Fan, X.; Shevchenko, N.; Clark, S.; Marussi, S.; Shah, S.; Atwood, R.; Eckert, S.; Kao, A.; Lee, P.

During directional solidification, segregation of alloying components may lead to channels of segregate forming, called ‘freckle’. This work aims to understand how the application of a magnetic field effects freckle formation.
Using synchrotron X-ray imaging we quantify the influence of magnetic field strength and orientation on the formation, growth and motion of freckle channels and the resulting suppression of the solidification temperature.By increasing the Bz magnetic component (perpendicular to the sample surface, freckle channels can be driven to one side and suppressed elsewhere, giving a freckle free region in otherwise difficult to cast alloys. The freckle motion can be attributed to the thermoelectric Lorentz force acting on the liquid, changing inter-dendritic liquid flow by causing the solute-enriched liquid to accumulate at one side, biasing channel motion. In the bulk liquid electromagnetic damping force prevails, decreasing the solidification temperature.

Keywords: Solidification; Freckle defects; Magnetic fields; Synchrotron imaging

  • Lecture (Conference) (Online presentation)
    TMS 2021, annual Meeting & Exhibition, 15.-18.03.2021, Web-conference, USA

Permalink: https://www.hzdr.de/publications/Publ-33749
Publ.-Id: 33749


Multi-source hyperspectral imaging of drill cores for the exploration of critical minerals

Kirsch, M.; Lorenz, S.; Booysen, R.; Thiele, S. T.; Tusa, L.; Saffi, H.; Zimmermann, R.; Contreras Acosta, I. C.; Gering, L.; Gloaguen, R.

Access to primary and secondary raw materials, particularly critical raw materials (CRM), is a prerequisite for a transition to a climate-neutral and circular economy and a successful delivery of the United Nations sustainable development goals (Ali et al., 2017). Resourceand energy-efficient exploration technologies such as hyperspectral imaging will aid discovery and evaluation of ore deposits, and thus contribute to sustaining a supply of CRM. Hyperspectral imaging provides fast, highresolution, spatially continuous, and non-destructive mapping of minerals along drill cores. This spectroscopic technique uses the spectral reflectance and emission measured in hundreds of contiguous spectral bands to provide information about geological materials based on electronic and vibrational processes of bonded elements within minerals. Below we demonstrate the application of hyperspectral drill core scanning for the identification and mapping of CRMs using a case study of Li-bearing pegmatites in Uis, Namibia.

  • Invited lecture (Conferences) (Online presentation)
    Critical Minerals: From discovery to supply chain, 16.-18.11.2021, Virtual, Virtual

Permalink: https://www.hzdr.de/publications/Publ-33748
Publ.-Id: 33748


Overview over DAPHNE-related activities at HZDR

Kluge, T.

Overview over DAPHNE-related activities at HZDR

  • Lecture (others) (Online presentation)
    DAPHNE Kick-Off Meeting, 01.12.2021, Online, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33747
Publ.-Id: 33747


Asymmetries in resonant SAXS

Kluge, T.; Gaus, L.; Huang, L.; Schlenvoigt, H.-P.; Schramm, U.; Cowan, T.

Asymmetries in resonant SAXS

  • Lecture (Conference) (Online presentation)
    Workshop on SAXS@XFELs and HI & HE laser driven matter, 04.-05.11.2021, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33746
Publ.-Id: 33746


Targets for pump probe experiments at upcoming XFEL facilities

Kluge, T.; Gaus, L.; Prencipe, I.; Schlenvoigt, H.-P.; Schramm, U.; Cowan, T.

Targets for pump probe experiments at upcoming XFEL facilities

  • Lecture (Conference) (Online presentation)
    TARG5, 25.-27.10.2021, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33745
Publ.-Id: 33745


Stretcher Compressor Simulation with Aberrated Optics

Hornung, M.; Siebold, M.; Löser, M.; Schramm, U.; Kaluza, M. C.

We performed simulations for CPA stretcher compressor systems with measured aberrated optic surfaces. These simulations were developed to understand and further optimize the temporal pulse structure of laser pulses which were stretched and compressed with existing and planned stretcher compressor systems.

Keywords: Laser; CPA; Stretcher; Athena; Compressor

  • Open Access Logo Contribution to external collection
    Daniel Seipt and Arno Klenke: Helmholtz Institute Jena Annual Report 2020, Jena: Helmholtz ­Institut Jena, 2021
    DOI: 10.15120/GSI-2021-00839

Permalink: https://www.hzdr.de/publications/Publ-33743
Publ.-Id: 33743


ATHENA: A high-contrast frontend for the PEnELOPE laser facility

Schramm, U.; Albach, D.; Siebold, M.; Löser, M.; Hornung, M.; Becker, G. A.; Weickhardt, T.; Hellwing, M.; Kaluza, M. C.

Within the framework of the ATHENA project, we are developing a high-contrast frontend to generate laser pulses with a center wavelength of 1030 nm, a
FWHM-bandwidth of 25 nm and an output energy of 100 μJ. The system is based on chirped pulse amplification with subsequent crossed polarized wave generation [1]. The generated laser pulses will in future be used as seed pulses at the PEnELOPE [2] laser facility at HZDR.

Keywords: Laser; CPA; Athena

  • Open Access Logo Contribution to external collection
    Daniel Seipt and Arno Klenke: Helmholtz Institute Jena Annual Report 2020, Jena: Helmholtz ­Institut Jena, 2021
    DOI: 10.15120/GSI-2021-00839

Permalink: https://www.hzdr.de/publications/Publ-33742
Publ.-Id: 33742


Metallogenic relevance of trace element systematics in skarn-related garnet – the Morelos district in Mexico as a case study

Faizy, S. M.; Frenzel, M.; Mainert D, L.; Burisch-Hassel, M.

The Morelos district (Guerrero, Mexico) hosts several Au-Cu skarn deposits, i.e., the El Limon, Guajes and Media Luna deposits, that are centered around the El-Limon granodiorite. The three skarn deposits comprise a total Au endowment of 8.8 Moz at an average grade of 3.2 g/t (all classes). In addition, the Media Luna deposit (south) comprises 20.9 Mt at 1.07 wt.% Cu. This different metal tenor (Au-Cu vs. Au), has been interpreted to be related to higher Mg-concentrations in the sedimentary protolith at Media Luna.
Forty-two samples from eleven drill-cores from the El Limon (north) and Media Luna (south) deposits were selected along systematic depth profiles, including skarn samples in proximal, intermediate and distal position to the intrusion. The prograde skarn mineral association is characterized by mainly garnet, pyroxene and magnetite, whereas retrograde skarn minerals comprise amphibole, calcite and sulfide minerals (mainly pyrrhotite, arsenopyrite and chalcopyrite). Preliminary petrographic analyses of selected drill-core material reveal a systematic variation in garnet color from dark brown/red in proximal endo/exoskarn to green in intermediate exoskarn to pale green in distal marble-hosted garnet nodules.
After detailed mineralogical characterization (optical and scanning electron microscopy), we are planning to analyze major and trace element compositions of skarn-related garnet by electron microprobe analysis and laser ablation – inductively coupled- mass spectrometry. The goal of this study is to constrain trace element systematics in the prograde skarn stage along the fluid flow path as well as to assess the influence of different host rock compositions on garnet trace element chemistry.

  • Lecture (Conference)
    GOOD Meeting 2021, 07.-09.10.2021, Clausthal, Germany

Permalink: https://www.hzdr.de/publications/Publ-33741
Publ.-Id: 33741


Ultra-short pulse laser-driven acceleration of protons to 80 MeV from density tailored cryogenic hydrogen jets

Rehwald, M.; Bernert, C.; Brack, F.-E.; Cowan, T.; Curry, C. B.; Fiuza, F.; Garten, M.; Gaus, L.; Gauthier, M.; Göde, S.; Göthel, I.; Glenzer, S. H.; Hübl, A.; Kim, J. B.; Kluge, T.; Kraft, S.; Kroll, F.; Metzkes-Ng, J.; Löser, M.; Obst-Hübl, L.; Reimold, M.; Schlenvoigt, H.-P.; Schoenwaelder, C.; Schramm, U.; Siebold, M.; Treffert, F.; Ziegler, T.; Zeil, K.

Laser plasma based particle accelerators have attracted great interest in fields where conventional accelerators reach limits based on size, cost or beam parameters. Designing future laser ion accelerators requires a high degree of control of the advanced acceleration schemes involved and predictive modelling capabilities. Here, we investigate the interaction of petawatt class laser pulses with a micrometer sized cryogenic hydrogen jet target. Controlled pre-expansion of the target by low intensity pre-pulses allowed for tailored density scans over more than two orders of magnitude. On-shot target characterization using two-color optical probing provided precise starting conditions for numerical simulations. For the optimal target density profile in the near critical regime proton energies of up to 80 MeV were observed which represents a two-fold increase with respect to the initial solid target case. Three-dimensional particle in cell simulations confirmed the transition between different acceleration mechanisms involved and suggested the magnetic-vortex regime to be responsible for the highest proton energies achieved.

  • Lecture (Conference) (Online presentation)
    7. Annual MT Meeting, 16.-18.06.2021, Online, Deutschland
  • Lecture (Conference)
    20th Advanced Accelerator Concepts Workshop, 06.-11.11.2022, Hyatt Regency Long Island, Hauppauge, USA

Permalink: https://www.hzdr.de/publications/Publ-33740
Publ.-Id: 33740


Cryogenic sheet jet targets produced from liquid hydrogen for high repetition rate experiments

Rehwald, M.; Assenbaum, S.; Bernert, C.; Loureiro, D.; Yang, F.; Schramm, U.; Zeil, K.; Göde, S.

Cryogenic jet targets are attracting growing attention in scientific fields investigated at x-ray free electron laser and high power laser facilities, e.g. in high energy density science exploring extreme states of matter or in relativistic laser plasma interactions aiming to develop novel ion accelerators.
A key advantage of cryogenic target is the unique capability to deliver ultra-pure samples at solid density using chemical elements that under ambient conditions exist in the gas phase (e.g. hydrogen) and to generate replenishing, free-standing, debris free targets at high repetition rates.
Novel sheet-like jets geometries enable wider target with adjustable thickness, which is e.g. of interest for the study of different acceleration mechanisms in laser-plasma experiment.
In this talk, we present experimental studies on the characterization of sheet jets for different nozzle types and under various operation conditions. Unlike cylindrical geometries, the shape of the planar target is significantly altered by surface tension until the liquid motion is stopped by solidification. The underlining fluid dynamics and thermodynamics are discussed and compared with computational fluid dynamic simulations.

  • Lecture (Conference)
    TARG5 Targetry for High Repetition Rate Laser-Driven Sources Workshop, 25.-27.10.2021, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33739
Publ.-Id: 33739


Novel Machine Learning Approaches in Image-based Host-pathogen Interactions Analysis

Yakimovich, A.

The research of interactions between the pathogens and their hosts is key for understanding the biology of infection. Commencing on the level of individual molecules, these interactions define the behavior of infectious agents and the outcomes they elicit. Discovery of host-pathogen interactions (HPIs) conventionally involves a stepwise laborious research process. However novel computational approaches including machine learning and deep learning allow to significantly accelerate the discovery process, particularly for rich information sources like microscopy. One example of such approaches includes an algorithm we have devised to detect interactions between intracellular Toxoplasma gondii parasites and the host cell innate immune response molecules with high accuracy from micrographs obtained in high-content fashion. In another example, it was possible to detect intracellular and extracellular poxvirus virions in 3D superresolution micrographs without specific immunohistochemical labelling. This was possible through transfer-learning-enabled deep learning model inference from seemingly irrelevant fluorescence channels, allowing to distinguish minute changes in virus particle signal upon internalization. Finally, bringing temporal dimension as a source of information for deep learning algorithms allows predicting infection outcomes in a population of infected and uninfected host cells employing time-lapse microscopy data. Altogether, these examples suggest a great potential for HPI analysis using novel machine learning.

Keywords: deep learning; machine learning; host-pathogen interactions; microscopy

  • Open Access Logo Lecture (Conference) (Online presentation)
    6th International Symposium on Systems Biology of Microbial Infections, 11.-12.11.2021, Jena, Germany

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Permalink: https://www.hzdr.de/publications/Publ-33738
Publ.-Id: 33738


Hyperspectral imaging with UAVs for mineral exploration

Booysen, R.; Lorenz, S.; Kirsch, M.; Jackisch, R.; Zimmermann, R.; Gloaguen, R.

Conventional mineral exploration methods are usually based on extensive field work supported by geophysical surveying. These techniques can be restricted by field accessibility, financial status, area size and climate. Additionally, these methods can have a considerable footprint on the environment, upsetting the surrounding community and resulting in mistrust in the exploration sector. To tackle these challenges, we propose to use UAVs during the exploration phase in order to decrease conventional restrictions. The rise in expertise and new sensor technology have allowed geoscientists to apply a wide range of optical remote sensing methods for exploration. Light-weight UAVs have shown to be a fast and flexible tool in aerial surveying for geological purposes (e.g. Madjid et al., 2018; Xiang et al., 2018).
Furthermore, the addition of UAV-based hyperspectral data can improve the accuracy of field mapping and provide the needed information of the geochemical make-up of outcropping deposits for future exploration campaigns (e.g. Booysen et al., 2020). UAV-based surveying can supplement and direct geological observation immediately during fieldwork and thus allow for a better integration with in-situ ground measurements. In particular, such systems are beneficial for inaccessible and remote areas with little infrastructure because they allow for a systematic, dense and non-invasive surveying that might not be possible with ground-based techniques. In this contribution, we will present the various UAVs and payloads used in our field campaigns that acquired data for geological purposes.

  • Invited lecture (Conferences) (Online presentation)
    Second EAGE Workshop on 
Unmanned Aerial Vehicles, 15.-16.11.2021, Online, Online

Permalink: https://www.hzdr.de/publications/Publ-33737
Publ.-Id: 33737


Multi-scale and multi-source remote sensing of REEs in southern Africa

Booysen, R.; Zimmermann, R.; Jackisch, R.; Gloaguen, R.; Kirsch, M.; Lorenz, S.

Technological advancements have led to an increased demand for rare earth elements (REEs), resulting in them becoming crucial to ensure the transformation towards green technologies (Dutta et al., 2016). At the same time, the world’s REE supply is monopolized by a limited number of countries (Simandl, 2014). A renewed and sustainable exploration approach is required to ensure a more ethical and global supply of REEs. For this, we suggest the use of a multi-scale and multi-source remote sensing workflow. Conventional exploration methods typically involve extensive field work and geochemical lab work supported by geophysical surveying. This approach, however, can be constrained by several factors such as the area size and accessibility, climate, finances as well as the lack of a social licence to operate. The suggested multi-scale, multi-source approach uses optical remote sensing data from multiple platforms with increasing spatial resolution. We utilize multispectral satellite data, plane-based hyperspectral data, unmanned aerial vehicle (UAV)-based hyperspectral data and validate the findings with in-situ measurements. Our suggested method can mitigate the disadvantages of traditional exploration techniques by allowing for fast, systematic and dense surveying, particularly in inaccessible and remote areas with little infrastructure. Additionally, a generally less-invasive technique garners a higher social acceptance for the mining and exploration community. We demonstrate our approach on a few, selected carbonatite complexes in southern Africa: the Marinkas Quellen carbonatite complex and the Lofdal carbonatite complex in Namibia.

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    Critical Minerals: From discovery to supply chain, 16.-18.11.2021, Online, Online

Permalink: https://www.hzdr.de/publications/Publ-33736
Publ.-Id: 33736


INFACT - The future of mineral exploration in the EU

Lorenz, S.

How can we shape the future of mineral exploration in the EU? And how did the Horizon 2020 project INFACT, which stands for innovative, non-invasive and fully acceptable exploration technologies contribute to move towards a sustainable and socially acceptable exploration in the EU?

  • Invited lecture (Conferences) (Online presentation)
    EU Raw Materials Week - EU Horizon Technology Success Stories, 15.11.2021, online, online

Permalink: https://www.hzdr.de/publications/Publ-33735
Publ.-Id: 33735


Physics of Inhomogeneous Warm Dense Matter

Moldabekov, Z.

Warm dense matter (WDM) is an interdisciplinary field between plasma physics, condensed matter physics, high pressure science, inertial confinement fusion, planetary science, and materials science under extreme conditions [1-3]. Therefore, WDM is a complex regime to which neither ordinary condensed matter theory nor plasma theory are applicable. Due to relatively well developed theoretical and computational methods for homogeneous states, most of the initial studies were focused on uniform WDM. However, recent introduction of THz lasers [4], the novel seeding technique to reach high intensities [5], and laser pumping of a sample with a predesigned periodic grating structure [6] allows us to generate inhomogeneous states. Therefore, in this talk the results will be presented for collective oscillations in inhomogeneous WDM. Additionally, the non-linear density response of electrons and applicability of various exchange-correlation functionals such as LDA, GGA, and meta-GGA will be discussed. The analysis of the quality of the KS-DFT approach based on different exchange-correlations functionals is performed by comparing to QMC data. Finally, the quantum fluid theory of inhomogeneous quantum electrons will be presented. The results on the first ab inito study of the many-fermion Bohm field will be shown. The latter has impact going well beyond WDM, since it is key quantity of Bohmenian quantum mechanics.

[1] A. Ng, IEEE International Conference on Plasma Science (Cat. No.02CH37340),
2002, pp. 163-, doi: 10.1109/PLASMA.2002.1030367.
[2] F. Graziani, M. P. Desjarlais, R. Redmer, and S. B. Trickey, Frontiers and Chal-
lenges in Warm Dense Matter (Springer, 2014).
[3] V. E. Fortov,Extreme States of Matter (Springer, Heidelberg, 2016).
[4] B.K. Ofori-Okai, et al., J. Inst13, P06014 (2018).
[5] T Kluge, et al., Phys. Rev. X 8, 031068 (2018)

Keywords: warm dense matter

  • Invited lecture (Conferences)
    The Seminar of the Institute of Theoretical Physics of the University of Wroclaw., 05.11.2021, Wroclaw, Poland

Permalink: https://www.hzdr.de/publications/Publ-33734
Publ.-Id: 33734


Physics beyond homogeneous warm dense matter

Moldabekov, Z.

Warm dense matter (WDM) is a state of matter covering parameter space between solids and dense plasmas, and is characterized by the simultaneous relevance of electronic quantum degeneracy, thermal excitations, and strong inter-particle correlations. WDM is an interdisciplinary field between plasma physics, condensed matter physics, high pressure science, inertial confinement fusion, planetary science, and materials science under extreme conditions [1-3]. Therefore, WDM is a complex regime to which neither ordinary condensed matter theory nor plasma theory are applicable. In particular, a highly ionized WDM state is closely related to a non-ideal dense plasma state. Parameters of relevant WDM experiments are shown in Fig.1 along with other types of plasma states. Due to relatively well developed theoretical and computational methods for homogeneous states, most of the initial studies were focused on uniform WDM. However, recent introduction of THz lasers [4], the novel seeding technique to reach high intensities [5], and laser pumping of a sample with a pre-designed periodic grating structure [6] allows us to generate inhomogeneous states. Therefore, this talk will be focused on inhomogeneous states.
In particular, periodically inhomogeneous WDM is considered. The results will be presented for collective oscillations in such systems. It will be shown that such interesting features like double plasmon and optical mode appear in electronic density excitation spectra. Additionally, the non-linear density response of electrons and applicability of various exchange-correlation functionals such as LDA, GGA, and meta-GGA will be discussed. The analysis of the quality of the KS-DFT approach based on different exchange-correlations functionals is performed by comparing to QMC data. Finally, the quantum fluid theory of inhomogeneous quantum electrons will be presented. The results on the first ab inito study of the many-fermion Bohm field will be shown. The latter has impact going well beyond WDM, since it is key quantity of Bohmenian quantum mechanics.

[1] A. Ng, IEEE International Conference on Plasma Science (Cat. No.02CH37340),
2002, pp. 163-, doi: 10.1109/PLASMA.2002.1030367.
[2] F. Graziani, M. P. Desjarlais, R. Redmer, and S. B. Trickey, Frontiers and Chal-
lenges in Warm Dense Matter (Springer, 2014).
[3] V. E. Fortov,Extreme States of Matter (Springer, Heidelberg, 2016).
[4] B.K. Ofori-Okai, et al., J. Inst13, P06014 (2018).
[5] T Kluge, et al., Phys. Rev. X 8, 031068 (2018).

Keywords: Warm dense matter

  • Invited lecture (Conferences)
    Physics beyond homogeneous warm dense matter, 20.09.2021, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-33733
Publ.-Id: 33733


Drone-based magnetic and multispectral surveys to develop a 3D model for mineral exploration at Qullissat, Disko Island, Greenland

Jackisch, R.; Heincke, B. H.; Zimmermann, R.; Sørensen, E. V.; Pirttijärvi, M.; Kirsch, M.; Salmirinne, H.; Lode, S.; Kuronen, U.; Gloaguen, R.

Mineral exploration in the West Greenland flood basalt province is attractive because of its resemblance to the magmatic sulphide-rich deposit in the Russian Norilsk region, but it is challenged by rugged topography and partly poor exposure for relevant geologic formations. On northern Disko Island, previous exploration efforts have identified rare native iron occurrences and a high potential for Ni-Cu-Co-PGE-Au mineralization. However, Quaternary landslide activity has obliterated rock exposure at many places at lower elevations. To augment prospecting field work under these challenging conditions, we acquire high-resolution magnetic and optical remote sensing data using drones in the Qullissat area. From the data, we generate a detailed 3D model of a mineralized basalt unit, belonging to the Asuk Member (Mb) of the Palaeocene Vaigat formation.

A wide range of legacy data and newly acquired geo- and petrophysical, as well as geochemical-mineralogical measurements form the basis of an integrated geological interpretation of the unoccupied aerial system (UAS) surveys. In this context, magnetic data aims to define the location and the shape of the buried magmatic body, and to estimate if its magnetic properties are indicative for mineralization. High-resolution UAS-based multispectral orthomosaics are used to identify surficial iron staining, which serve as a proxy for outcropping sulphide mineralization. In addition, high-resolution UAS-based digital surface models are created for geomorphological characterisation of the landscape to accurately reveal landslide features.

UAS-based magnetic data suggests that the targeted magmatic unit is characterized by a pattern of distinct positive and negative magnetic anomalies. We apply a 3D magnetization vector inversion model (MVI) on the UAS-based magnetic data to estimate the magnetic properties and shape of the magmatic body. By means of using constraints in the inversion, (1) optical UAS-based data and legacy drill cores are used to assign significant magnetic properties to areas that are associated with the mineralized Asuk Mb, and (2) the Earth’s magnetic and the paleomagnetic field directions are used to evaluate the general magnetization direction in the magmatic units.

Our results indicate that the geometry of the mineralized target can be estimated as a horizontal sheet of constant thickness, and that the magnetization of the unit has a strong remanent component formed during a period of Earth’s magnetic field reversal. The magnetization values obtained in the MVI are in a similar range as the measured ones from a drillcore intersecting the targeted unit. Both the magnetics and topography confirm that parts of the target unit were displaced by landslides. We identified several fully detached and presumably rotated blocks in the obtained model. The model highlights magnetic anomalies that correspond to zones of mineralization and is used to identify outcrops for sampling.

Our study demonstrates the potential and efficiency of using multi-sensor high-resolution UAS data to constrain the geometry of partially exposed geological units and assist exploration targeting in difficult, poorly exposed terrain.

Permalink: https://www.hzdr.de/publications/Publ-33732
Publ.-Id: 33732


Ambient seismic noise analysis of LARGE-N data for mineral exploration in the Central Erzgebirge, Germany

Ryberg, T.; Kirsch, M.; Haberland, C.; Tolosana Delgado, R.; Viezzoli, A.; Gloaguen, R.

Ambient seismic noise tomography is a novel, low-impact method to investigate the Earth’s structure. While most passive seismic studies focus on structures at crustal scales, there are only few examples of this technique being applied in a mineral exploration context. In this study, we performed an ambient seismic experiment to ascertain the relationship between the shallow shear wave velocity and mineralized zones in the Erzgebirge in Germany, one of the most important metal provinces in Europe. Late Variscan mineralized greisen and veins occurring in the Geyer-Ehrenfriedersdorf mining district of the Central Erzgebirge were mined from medieval times until the end of the 19th century. These occurrences represent a significant resource for commodities of high economic importance, such as tin, tungsten, zinc, indium, bismuth and lithium. Based on ambient noise data from a dense "LARGE-N" network comprising 400 low-power, short-period seismic stations, we applied an innovative tomographic inversion technique based on Bayesian statistics (transdimensional, hierarchical Monte Carlo search with Markov Chains using a Metropolis/Hastings sampler) to derive a three-dimensional shear wave velocity model. An auxiliary 3D airborne time-domain electromagnetic dataset is used to provide additional insight into the subsurface architecture of the area. The velocity model shows distinct anomalies down to approximately 500 m depth that correspond to known geological features of the study area, such as (a) gneiss intercalations in the mica schist-dominated host rock, imaged by a SW-NE striking low velocity zone with a moderately steep northerly dip, and (b) a NW-trending strike-slip fault, imaged as a subvertical linear zone cross-cutting and offsetting this low velocity domain. Similar to the velocity data, the electromagnetic data exhibit north-dipping (high-conductivity) structures in the mica schists, corresponding to the strike and dip of the predominant metamorphic fabric. An unsupervised classification performed on the bivariate 3D dataset yielded nine spatially coherent classes, one of which shows a high correspondence to drilled greisen occurrences in the roof zone of a granite pluton. The relatively high mean shear velocity and resistivity values of this class could be explained by changes in density and composition during greisen formation as observed in other areas of the Erzgebirge. Our study demonstrates the great potential of the cost-efficient and low-impact ambient noise technology for mineral exploration, especially when combined with other independent geophysical datasets.

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Permalink: https://www.hzdr.de/publications/Publ-33731
Publ.-Id: 33731


Integrated Test Sites for Innovation Ecosystems

Kesselring, M.; Ruiz-Coupeau, S.; Kirsch, M.; Wagner, F.; Gloaguen, R.

Natural test sites are resource-intensive and often limited to single industries or technologies. Drawing upon two strands of research into technology development and innovation strategies, the research question in this paper investigates how converging test sites may provide opportunities for multiple industries and regions. The paper analyzes multi-industrial test sites regarding, (i) the requirements of the social and physical environment, logistic requirements, as well as technical requirements, (i) the added value for technology developers, as well as, (iti) the absorptive capacity of the region. Qualitative and quantitative research designs were adopted to analyze multi-industrial test sites. The results indicate that the suitability of multiindustrial test sites depends on the market and research fit of the test target, the quality of the benchmark data, as well as logistical, organizational, legal, social, and ecological factors. The study shows that multi-industrial test sites increase and strengthen the absorptive capacity of regions. Additionally, the study discusses managerial and political implications of multiindustrial test sites. Until now corporate and public test site practices have received only scant recognition in technology management literature, a gap closed by this paper.

Permalink: https://www.hzdr.de/publications/Publ-33730
Publ.-Id: 33730


Characterisation of Massive Sulphide Deposits in the Iberian Pyrite Belt Based on the Integration of Digital Outcrops and Multi-Scale, Multi-Source Hyperspectral Data

Kirsch, M.; Lorenz, S.; Thiele, S. T.; Gloaguen, R.

Geological mapping in difficult-to-access terrain such as open pit mines often relies on remotely sensed data. Hyperspectral data yield valuable geological information, especially when spectral ranges of multiple sensors are used in conjunction. In this contribution we project a number of hyperspectral datasets of an open pit mine covering the visible to near-infrared (VNIR), short-wave infrared (SWIR), and long-wave infrared (LWIR) range from airborne, drone-borne and ground-based acquisitions into a photogrammetric point cloud. The resulting hyperspectral digital outcrop is then used as a basis for data integration in a 3D environment. To discriminate geologic materials in the pit we apply a Gaussian deconvolution to identify the position of diagnostic absorption features in the SWIR and LWIR, and then apply a support vector machine-based classification. Our results agree with known lithologic units and alteration patterns and can be used to guide exploration targeting and mine planning.

Keywords: Hyperspectral imaging; exploration; geology; intergration

  • Contribution to proceedings
    2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 11.-16.07.2021, Brussels, Belgium
    2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS: IEEE, 978-1-6654-0369-6
    DOI: 10.1109/IGARSS47720.2021.9554149
    Cited 1 times in Scopus

Permalink: https://www.hzdr.de/publications/Publ-33729
Publ.-Id: 33729


Berührungslose induktive Strömungstomographie für Modelle des kontinuierlichen Stranggießens von Stahl

Ratajczak, M.

Das Stranggießen von Stahl ist mit 96 % Marktanteil das weltweit wichtigste Verfahren zur Stahlherstellung. Im Gießprozess beeinflusst das Strömungsprofil in der Kokille entscheidend die Qualität des erstarrten Stahls. Um eine möglichst optimale Kokillenströmung einzustellen, werden Aktuatoren eingesetzt, die die sich bewegende Schmelze kontaktlos mithilfe der Lorentzkraft beeinflussen. Diese Aktuatoren würden auch eine Strömungsregelung ermöglichen, wenn eine geeignete Messtechnik für heiße Schmelzen vorhanden wäre. Allerdings lösen bislang verfügbare Messverfahren vor allem die Strömung im Randgebiet der Kokille auf und sind häufig in ihrer zeitlichen Auflösung limitiert. Eine neue infrage kommende Messtechnik ist die berührungslose induktive Strömungstomographie (contactless inductive flow tomography, CIFT), die aus der gemessenen strömungsinduzierten Verzerrung eines angelegten Magnetfeldes die dreidimensionale Strömung rekonstruieren kann. In dieser Arbeit wird anhand eines 1:8-Labormodells einer Stranggusskokille und numerischen Simulationen untersucht, ob CIFT bei Anlagen mit elektromagnetischen Bremsen eingesetzt werden kann. Besondere Herausforderungen entstehen aufgrund der Verzerrung des CIFT-Anregungsmagnetfeldes durch die ferromagnetische Bremse, der großen Dynamik von 6 Größenordnungen zwischen dem Magnetfeld der Bremse und dem strömungsinduzierten Magnetfeld sowie intrinsischen Strömungsoszillationen mit einer charakteristischen Frequenz im Bereich der üblicherweise verwendeten CIFT-Anregungsfrequenzen. Es wird dargelegt, dass sich CIFT in derartigen Aufbauten einsetzen lässt, wenn (a) eine geeignete Anregungsmagnetfeldstruktur erzeugt werden kann, (b) gradiometrische Induktionsspulen als Magnetfeldsensoren eingesetzt werden und (c) die Anregungsfrequenz in einem optimalen, schmalen Bereich gewählt wird. Diese Messungen werden erst durch in dieser Arbeit dargelegte theoretische und experimentell validierte Analysen der Induktionsspulen möglich, wofür Schwerpunkte auf deren Modellierung, Design und Messunsicherheit gelegt wurden. Außerdem werden für dieses Stranggussmodell erstmals experimentelle Ergebnisse mit horizontal anstatt vertikal orientierten Anregungsmagnetfeldern präsentiert. Um die Skalierbarkeit von CIFT in Richtung industrieller Anlagen zu demonstrieren, werden zum einen CIFT-Strömungsrekonstruktionen in einem heißen 1:2-Labormodell einer Kokille vorgestellt. Eine weitere Herausforderung für CIFT ist die in industriellen Kokillen typischerweise aufgebrachte ferromagnetische Nickelschicht, die eine verzerrende und abschirmende Wirkung auf umgebende Magnetfelder hat. Diese Beschichtung stellt aufgrund ihrer zeitlich und räumlich schwankenden Permeabilität eines der größten Hindernisse für die Anwendung von CIFT im industriellen Stahlguss dar. Die Auswirkung dieser Beschichtung auf CIFT wird mit numerischen Simulationen quantifiziert. Dabei werden neue, im Rahmen dieser Arbeit patentierte Anregungsgeometrien untersucht und erste Strömungsrekonstruktionen gezeigt.

  • Lecture (others)
    Verleihung Preise der Gisela und Erwin Sick Stiftung, 21.10.2021, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33728
Publ.-Id: 33728


Data publication: Thermal Excitation Signals in the Inhomogeneous Warm Dense Electron Gas

Moldabekov, Z.; Dornheim, T.; Cangi, A.

The KS-DFT simulation results for electron energy loss function (EELF)

Keywords: warm dense matter

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Permalink: https://www.hzdr.de/publications/Publ-33726
Publ.-Id: 33726


Data publication: Higher harmonics in complex plasmas with alternating screening

Moldabekov, Z.; Aldakul, Y. K.; Bastykova, N. K.; Sundar, S.; Cangi, A.

The data for the spectrum of the density fluctuations from MD simulations

Keywords: plasma physics; strongly correlated plasmas; complex plasmas

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Permalink: https://www.hzdr.de/publications/Publ-33724
Publ.-Id: 33724


Data publication: Towards a Quantum Fluid Theory of Correlated Many-Fermion Systems from First Principles

Moldabekov, Z.; Dornheim, T.; Gregori, G.; Graziani, F.; Bonitz, M.; Cangi, A.

KS-DFT simulations results for wave functions and total densities used to compute Bohm potential

Keywords: warm dense matter; Condensed Matter Physics - Computational

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Permalink: https://www.hzdr.de/publications/Publ-33723
Publ.-Id: 33723


Data publication: Benchmarking Exchange-Correlation Functionals in the Spin-Polarized Inhomogeneous Electron Gas under Warm Dense Conditions

Moldabekov, Z.; Dornheim, T.; Vorberger, J.; Cangi, A.

DFT simulation results for the total density distribution

Keywords: warm dense matter; Strongly Correlated Electrons; Density functional theory

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Permalink: https://www.hzdr.de/publications/Publ-33722
Publ.-Id: 33722


Data publication: Shock Physics in Warm Dense Matter--a quantum hydrodynamics perspective

Graziani, F.; Moldabekov, Z.; Olson, B.; Bonitz, M.

Figures of the shock propagation

Keywords: warm dense matter; shock propagation; quantum hydrodynamics

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Permalink: https://www.hzdr.de/publications/Publ-33721
Publ.-Id: 33721


On the route for detecting vacuum birefringence at an XFEL combined with a PW-class laser

Schlenvoigt, H.-P.; Bähtz, C.; Goede, S.; Huang, L.; Konôpková, Z.; Laso García, A.; Lötzsch, R.; Marx-Glowna, B.; Pelka, A.; Schulze, K.-S.; Strohm, C.; Toncian, T.; Uschmann, I.; Yu, Q.; Röhlsberger, R.; Sauerbrey, R.; Schramm, U.; Stöhlker, T.; Paulus, G. G.; Cowan, T.

Vacuum birefringence as a clear variant of light-by-light scattering is a feasible experiment at an XFEL combined with a PW-class laser. Such experiment would measure the birefringence of vacuum – induced by the giant electromagnetic field in the focus of the PW laser – directly by ultra-sensitive X-ray polarimetry. In this way, the effect depends on real photons of externally controllable beams, complementary to other effects where photon-photon couplings are in play. The HIBEF user consortium at the European XFEL is aiming for such experiment. We will give a status update on the progress made in recent beamtimes, concerning a) the polarimeter extinction for a well-collimated (laser-like) X-ray beam, b) the X-ray optics to be used inside the polarimeter, c) self-seeded operation of the XFEL and d) assuring best focusing/intensity verification.

  • Lecture (Conference) (Online presentation)
    Satellite Meeting 2021 of the 47th Conference on Plasma Physics, 28.-29.06.2021, Salamanca, Spanien

Permalink: https://www.hzdr.de/publications/Publ-33719
Publ.-Id: 33719


Copper-64/Actinium-225-human anti-PSCA-IgG4 theranostics of a prostate cancer model

Bergmann, R.; Arndt, C.; Máthé, D.; Berndt, N.; Loureiro, L. R.; Kovács, N.; Szöllösi, D.; Hegedüs, N.; Kovács, T.; Kopka, K.; Bachmann, M.; Feldmann, A.

Ziel/Aim Although CAR T-cell therapy has demonstrated tremendous clinical efficacy particularly in hematological malignancies, the success in solid tumors is still limited. The combination of the immunotherapeutic (Uni)CAR T-cell therapy with target modules (TM) in solid tumors and radiotherapy could be an additional treatment option. Therefore, we developed a human prostate stem cell antigen (PSCA)-specific, IgG4-based TM radiolabeled with copper-64 (Cu-64) for imaging and with actinium-225 (Ac-225) for treatment.

Methodik/Methods A novel human PSCA-specific IgG4-based TM was conjugated with DOTAGA and radiolabeled with (Cu-64) and (Ac-255). The imaging and therapy were studied in NMRI Foxn1 nu/nu mice with xenotransplanted PSCA-expressing PC-3 tumors. Metabolic changes of the tumors were visualized with 18F-PSMA (PET), the physical size of the tumors and the distance between the vessels in the tumors (US) were measured.

Ergebnisse/Results The radiochemical yield for the Cu-64/Ac-255 TM was 96 % and 52 % respectively, the RCP of the products were g.t. 97 %. The xenotransplanted mice were intravenously injected with the Cu-64 labeled TM given as single dose. After fast distribution, the blood activity concentration decreased very slowly. At 31 h p.i. the activity was maximal in the tumors thereby reaching the optimal tumor to background ratios and only the liver was also visible with much lower activity. The Ac-225 treatment resulted in significant lower tumor size as compared with the control group after 40 days. Doubling time of tumor volume was increased from 15.0 days (control) to 38.6 days of the treatment group. The 18F-PSMA ligand uptake was decreased in the tumor periphery. In comparison to the tumor size the vessel density decreased to a lower extent.

Schlussfolgerungen/Conclusions We here present a Cu-64/Ac-225 labeled TM that allows the combination of (Uni)CAR T-cell immunotherapy with imaging with the Cu-64 labeled TM version and radiotherapy with the Ac-225 labeled TM version combined as radioimmunotheranostics.

  • Abstract in refereed journal
    Nuklearmedizin 60(2021)02
    DOI: 10.1055/s-0041-1726705
  • Lecture (Conference) (Online presentation)
    Virtual Annual DGN Meeting 2021, 15.04.2021, Deutschland, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33718
Publ.-Id: 33718


Charakterisierung zweiphasiger Feeds in Trennapparaten mit kritischen Stoffwerten

Döß, A.; Schubert, M.; Wiezorek, M.; Hampel, U.; Flegiel, F.; Windmeier, C.; Schleicher, E.

Stoffströme in Zuleitungen und im Eintrittsbereich von Trennapparaten müssen gezielt konditioniert und ausgelegt werden um problematische Prozesszustände zu vermeiden. Werden durch ungeeignete Einspeisegeometriene Konzentrations-, Temperatur- oder Impulsgradienten in den Zulauf (Feed) einer Trennkolonne oder eines Phasenabscheiders eingetragen, kann die Leistung der Eintrittsstufe beeinträchtigt werden. Im Falle zweiphasiger Feeds kann falsch ausgelegte Einspeisung beispielsweise zu erhöhter Tropfenbildung und -dispersion beitragen, Schäden am Außenmantel des Apparats hervorrufen oder zum Verblocken von Einbauten, wie Böden oder Ablaufschächten, führen.
Für eine Vielzahl praxisrelevanter Stoffsysteme erfolgt die Auswahl und die Dimensionierung notwendiger Zusatzausrüstung für die Einspeisung heuristisch und anhand von empirischen Korrelationen, welche hauptsächlich mit Daten für das Referenzsystem Wasser/Luft entwickelt wurden. Deren Übertragbarkeit auf kritische Stoffwerte (niedrige Grenzflächenspannung, niedrige Viskosität, hohe Dampfdichte) ist daher oft nur bedingt möglich. Gleiches gilt für die Auswahl geeigneter Einspeiseorgane für zweiphasige Feeds, die die Kenntnis von Phasenanteil und Strömungsform unter Prozessbedingungen (Feedleitungen mit großen Nennweiten und geringen Einlauflängen) erfordern.
In einer neuen Technikumsanlage am Helmholtz-Zentrum Dresden-Rossendorf wird ein Kreislaufprozess mit einem Kältemittel betrieben, mit dem zweiphasige Feeds bei kritischen Stoffwerten charakterisiert werden können. Eine modular aufgebaute Feedleitung (D = 200 mm, L = 20 D) ermöglich die Bestimmung von Strömungsformen flashender Feeds mittels bildgebender Gittersensorik.
Als Kältemittel wird 3MTM Novec 649TM eingesetzt, welches Untersuchungen bei niedrigen Oberflächenspannungen (<10 mN/m) und hohen Dampfdichten (18 bis 170 kg/m³) bei gleichzeitig hohen Dichtedifferenzen den Phasen (887 bis 1450 kg/m³) ermöglicht. Die auftretenden Strömungsmorphologien in der Feedleitung nahe der Entspannungsarmatur und am Kolonneneintritt wurden für verschiedene Massenströme und Dampfanteile charakterisiert und mit gängigen Strömungskarten und Wasser/Luft-Experimentaldaten verglichen.
Diese Arbeiten im Rahmen des Projektes TERESA wurden durch das Bundesministerium für Wirtschaft und Energie (BMWI) gefördert (FKZ 03ET1395).

  • Lecture (Conference) (Online presentation)
    Jahrestreffen Fluidverfahrenstechnik und Wärme- und Stoffübertragung 2021, 25.02.2021, HZDR (virtuelle Konferenz), Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33717
Publ.-Id: 33717


Imaging for particle therapy treatment planning

Richter, C.

The lecture will focus on tomographic imaging for particle therapy treatment planning, with special emphasis on the prediction of the stopping power ratio S(PR) as prerequisite for accurate range calculation. This knowledge is valid for both: Treatment planning before therapy start and for plan adaptations. Special emphasis will be on the application of Dual-Energy CT for direct SPR prediction.

  • Invited lecture (Conferences) (Online presentation)
    RAPTOR School - LOOP BASIC, 13.-17.12.2021, München, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33716
Publ.-Id: 33716


Ab initio Modeling of Plasmons in Aluminum under Ambient and Extreme Conditions

Cangi, A.; Dornheim, T.; Baczewski, A.; Vorberger, J.

The theoretical understanding of plasmon behavior is crucial for an accurate interpretation of inelastic scattering diagnostics in many experiments. We highlight the utility of linear-response time-dependent density functional theory (LR-TDDFT) as a first-principles framework for consistently modeling plasmon properties. We provide a comprehensive analysis of plasmons in aluminum from ambient to warm dense matter conditions and assess typical properties such as the dynamical structure factor, the plasmon dispersion, and the plasmon lifetime. We compare our results with scattering measurements and with other TDDFT results as well as models such as the random phase approximation, the Mermin approach, and the dielectric function obtained using static local field corrections of the uniform electron gas parametrized from path-integral Monte Carlo simulations. We conclude that results for the plasmon dispersion and lifetime are inconsistent between experiment and theories and that the common practice of extracting and studying plasmon dispersion relations is an insufficient procedure to capture the complicated physics contained in the dynamic structure factor in its full breadth.

  • Open Access Logo Lecture (Conference) (Online presentation)
    41st workshop on High-Energy-Density Physics with laser and ion beams, 01.02.2021, Virtual (online), Austria

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Permalink: https://www.hzdr.de/publications/Publ-33715
Publ.-Id: 33715


Electrical conductivity of Iron under Earth core conditions using time-dependent density functional theory

Ramakrishna, K.; Lokamani, M.; Vorberger, J.; Baczewski, A.; Cangi, A.

Iron is one of the most plentiful components on the planet earth and plays a crucial role in our lives. The analysis of iron at high pressures and temperatures is of great geophysical importance because iron makes up the majority of the Earth’s liquid outer core and solid inner core. The technical utility of iron is due to the large phase space of iron-based alloys, which is the source of a wide range of steel microstructures that can be produced with minor compositional changes and proper thermal treatment. The iron phase structure at the extreme conditions under the inner core conditions of the earth is still not conclusive especially in the vicinity of temperature around 6000 K and pressures nearing 300 GPa. Time-dependent
density functional theory (TDDFT) enables calculating electronic transport properties in warm dense matter (WDM) and is an alternative to present state-of-the-art approaches. In TDDFT, the electrical conductivity is computed from the time evolution of the electronic current density and provides direct means to assess the validity of Ohm’s law in WDM. We present TDDFT calculations of the electrical conductivity for iron within the pressure and temperature range found in Earth’s core. We discuss the ramifications of using TDDFT for calculating the electrical conductivity in contrast to the Kubo-Greenwood formalism and dielectric models.

Keywords: Warm dense matter; TDDFT; Matter under extreme conditions

  • Open Access Logo Lecture (Conference)
    17th International Conference on the Physics of Non-Ideal Plasmas, 21.09.2021, Dresden, Germany

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Permalink: https://www.hzdr.de/publications/Publ-33714
Publ.-Id: 33714


Electrical conductivity of materials under extreme conditions using TDDFT

Ramakrishna, K.; Vorberger, J.; Cangi, A.

Time-dependent density functional theory (TDDFT) enables calculating electronic transport properties in warm dense matter (WDM) and is an alternative to present state-of-the-art approaches. In TDDFT, the electrical conductivity is computed from the time evolution of the electronic current density and provides direct means to assess the validity of Ohm's law in WDM. We present TDDFT calculations of the electrical conductivity, for example in iron within the pressure and temperature range found in Earth's core. We discuss the ramifications of using TDDFT for calculating the electrical conductivity in contrast to the Kubo-Greenwood formalism and dielectric models.

Keywords: Warm dense matter; TDDFT; Matter under extreme conditions

  • Open Access Logo Lecture (Conference) (Online presentation)
    APS March meeting 2021, 19.03.2021, Virtual (online), USA

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Permalink: https://www.hzdr.de/publications/Publ-33713
Publ.-Id: 33713


LLAMA: The Low-Level Abstraction For Memory Access

Gruber, B. M.; Amadio, G.; Blomer, J.; Matthes, A.; Widera, R.; Bussmann, M.

The performance gap between CPU and memory widens continuously. Choosing the best memory layout for each hardware architecture is increasingly important as more and more programs become memory bound. For portable codes that run across heterogeneous hardware architectures, the choice of the memory layout for data structures is ideally decoupled from the rest of a program. This can be accomplished via a zero-runtime-overhead abstraction layer, underneath which memory layouts can be freely exchanged.
We present the Low-Level Abstraction of Memory Access (LLAMA), a C++ library that provides such a data structure abstraction layer with example implementations for multidimensional arrays of nested, structured data. LLAMA provides fully C++ compliant methods for defining and switching custom memory layouts for user-defined data types. The library is extensible with third-party allocators.
Providing two close-to-life examples, we show that the LLAMA-generated AoS (Array of Structs) and SoA (Struct of Arrays) layouts produce identical code with the same performance characteristics as manually written data structures. Integrations into the SPEC CPU® lbm benchmark and the particle-in-cell simulation PIConGPU demonstrate LLAMA's abilities in real-world applications. LLAMA's layout-aware copy routines can significantly speed up transfer and reshuffling of data between layouts compared with naive element-wise copying.
LLAMA provides a novel tool for the development of high-performance C++ applications in a heterogeneous environment.

Keywords: software implementation; programming techniques; memory layout; performance portability

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Permalink: https://www.hzdr.de/publications/Publ-33712
Publ.-Id: 33712


C++14

Gruber, B. M.

Talk on new features in C++14.

  • Open Access Logo Lecture (Conference) (Online presentation)
    ROOT team meeting, 06.09.2021, virtual, Switzerland

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Permalink: https://www.hzdr.de/publications/Publ-33711
Publ.-Id: 33711


LLAMA: The Low Level Abstraction of Memory Access

Matthes, A.; Gruber, B. M.; Widera, R.

LLAMA is a C++17 template header-only library for the abstraction of memory access patterns. It distinguishes between the view of the algorithm on the memory and the real layout in the background. This enables performance portability for multicore, manycore and gpu applications with the very same code.

Keywords: HPC; C++; memory layout; heterogeneous computing; performance portability

  • Software in external data repository
    Publication year 2021
    Programming language: C++
    System requirements: OS: Linux, Windows or MacOS, C++17, Boost 1.70+
    License: LGPL3+
    Hosted on Zenodo: Link to location
    DOI: 10.5281/zenodo.4911494
  • Software in external data repository
    Publication year 2022
    Programming language: C++
    System requirements: OS: Linux, Windows or MacOS, C++17, Boost 1.70+
    License: LGPL3+
    Hosted on Zenodo: Link to location
    DOI: 10.5281/zenodo.5901241
  • Software in external data repository
    Publication year 2023
    Programming language: C++
    System requirements: OS: Linux, Windows or MacOS, C++17, Boost 1.70+
    License: LGPL3+
    Hosted on Zenodo: Link to location
    DOI: 10.5281/zenodo.7590825

Permalink: https://www.hzdr.de/publications/Publ-33710
Publ.-Id: 33710


LLAMA hands-on seminar

Gruber, B. M.

In-depth introduction to LLAMA and hands-on coding session.

  • Lecture (Conference) (Online presentation)
    Hands-on LLAMA AoS vs SoA, 19.05.2021, virtual, Germany

Permalink: https://www.hzdr.de/publications/Publ-33709
Publ.-Id: 33709


LLAMA Memory layout optimization and efficient interconversion of data structures for heterogeneous architectures

Gruber, B. M.

Presentation of LLAMA and PhD progress at ZIH (center for information services and high performance computing - TU Dresden).

  • Lecture (Conference) (Online presentation)
    ZIH PhD seminar, 25.03.2021, virtual, Germany

Permalink: https://www.hzdr.de/publications/Publ-33708
Publ.-Id: 33708


SIMD and LLAMA in 10min

Gruber, B. M.

Short talk about alpaka, SIMD in C++, Vc, VecCore, LLAMA and std::simd.

  • Lecture (Conference) (Online presentation)
    Austausch zu Vektor Abstraktionen in Datenbanken, 17.03.2021, virtual, Germany

Permalink: https://www.hzdr.de/publications/Publ-33707
Publ.-Id: 33707


Full Integrated Research Data Lifecycle – The Project HELIPORT

Knodel, O.; Voigt, M.; Ufer, R.; Pape, D.; Lokamani, M.; Müller, S.; Gruber, T.; Juckeland, G.

Wissenschaftliche Experimente nutzen eine große Bandbreite an verschiedenen Software-Werkzeugen in den verschiedenen Phasen des Projektes von der Proposal-Einreichung über die Datennahme bis zur finalen Publikation. Eine große Herausforderung für Wissenschaftseinrichtungen ist es, WissenschaftlerInnen für die Dokumentation der genutzten Werkzeuge in allen Phasen des Forschungsprojektes zusätzliche Metadaten gemäß der FAIR-Prinzipien zur Verfügung zu stellen. Das Ziel der HELmholtz ScIentific Project WORkflow PlaTform (HELIPORT) ist es daher den kompletten Lebenszyklus eines wissenschaftlichen Projekts zu registrieren und die zugehörigen Programme und Systeme miteinander zu verknüpfen. Die maschinenlesbare Dokumentation aller im jeweiligen Forschungsprojekt durchgeführten Arbeitsschritte gemeinsam mit den dazugehörigen Metadaten macht jeden Arbeitsschritt transparent, verständlich und zitierbar und trägt somit zur Einhaltung guter wissenschaftlicher Praxis bei.

Keywords: Data Management; Metadata; FAIR; Data provenance; Digital Objects

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    Digital Kitchen von SaxFDM, 16.12.2021, online, Deutschland
    DOI: 10.5281/zenodo.5786706
  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    ZIH colloquium, 05.05.2022, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-33706
Publ.-Id: 33706


Development of a new Quantum Trajectory Molecular Dynamics Framework

Svensson, P.; Campbell, T.; Graziani, F.; Moldabekov, Z.; Richardson, S.; Vinko, S.; Gregori, G.

The dynamic properties of a warm dense matter (WDM) system is strongly influenced by electron dynamics. Therefore, there is a need for computational methods which explicitly treat the electron dynamics, while still scalable and independent on any equilibrium assumptions, for the ability to model ongoing experimental efforts. We present an extension of the wave packet molecular dynamic scheme, where the electron state has an arbitrary Gaussian form, increasing the degree of freedom in the model and allowing for anisotropy in collisional dynamics and molecular bonds. The model employs a generalised scheme for the computation of short-range interactions, Ewald summation and Pauli interactions. The highly parallelised molecular dynamics framework LAMMPS has been utilized for the implementation of the model, with the intention to allow investigations of larger-scale systems. We present both ground state as well as the thermodynamic properties of the model, specialising in hydrogen systems.

Keywords: warm dense matter; wave packet molecular dynamics

  • Lecture (Conference) (Online presentation)
    63rd Annual Meeting of the APS Division of Plasma Physics, 09.11.2021, Pittsburgh, PA, USA

Permalink: https://www.hzdr.de/publications/Publ-33705
Publ.-Id: 33705


Thermal Excitation Signals in the Inhomogeneous Warm Dense Electron Gas

Moldabekov, Z.; Dornheim, T.; Cangi, A.

We investigate the emergence of electronic excitations from the inhomogeneous electronic structure at warm dense matter parameters based on first-principles calculations. The emerging modes are controlled by the imposed perturbation amplitude. They include satellite signals around the standard plasmon feature, transformation of plasmons to optical modes, and double-plasmon modes. These modes exhibit a pronounced dependence on the temperature. This makes them potentially invaluable for the diagnostics of plasma parameters in the warm dense matter regime. We demonstrate that these modes can be probed with present experimental techniques.

Keywords: warm dense matter

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Permalink: https://www.hzdr.de/publications/Publ-33704
Publ.-Id: 33704


Benchmarking Exchange-Correlation Functionals in the Spin-Polarized Inhomogeneous Electron Gas under Warm Dense Conditions

Moldabekov, Z.; Dornheim, T.; Vorberger, J.; Cangi, A.

Warm dense matter is a highly active research area both at the frontier and interface of material science and plasma physics. We assess the performance of commonly used exchange-correlation (XC) approximation (LDA, PBE, PBEsol, and AM05) in the spin-polarized inhomogeneous electron gas under warm dense conditions based on exact path-integral quantum Monte-Carlo calculations. This extends our recent analysis on the relevance of inhomogeneities in the spin-unpolarized warm dense electron gas [Z.~Moldabekov et al., J. Chem. Phys. 155, 124116 (2021)]. We demonstrate that the predictive accuracy of these XC functionals deteriorates with (1) a decrease in density (corresponding to an increase in the inter-electronic correlation strength) and (2) an increase of the characteristic wave number of the density perturbation. We provide recommendations for the applicability of the considered XC functionals at conditions typical for warm dense matter. Furthermore, we hint at future possibilities for constructing more accurate XC functionals under these conditions.

Keywords: warm dense matter; Strongly Correlated Electrons; Density functional theory

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Permalink: https://www.hzdr.de/publications/Publ-33703
Publ.-Id: 33703


Towards a Quantum Fluid Theory of Correlated Many-Fermion Systems from First Principles

Moldabekov, Z.; Dornheim, T.; Gregori, G.; Graziani, F.; Bonitz, M.; Cangi, A.

Correlated many-fermion systems emerge in a broad range of phenomena in warm dense matter, plasmonics, and ultracold atoms. Quantum hydrodynamics (QHD) complements first-principles methods for many-fermion systems at larger scales. We illustrate the failure of the standard Bohm potential central to QHD for strong perturbations when the density perturbation is larger than about 10−3 of the mean density. We then extend QHD to this regime via the many-fermion Bohm potential from first-principles. This may lead to more accurate QHD simulations beyond their common application domain in the presence of strong perturbations at scales unattainable with first-principles methods.

Keywords: warm dense matter; Condensed Matter Physics - Computational

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Permalink: https://www.hzdr.de/publications/Publ-33702
Publ.-Id: 33702


Shock Physics in Warm Dense Matter--a quantum hydrodynamics perspective

Graziani, F.; Moldabekov, Z.; Olson, B.; Bonitz, M.

Warm dense matter (WDM)–an exotic, highly compressed state of matter between solid and plasma phases is of high current interest, in particular for astrophysics and inertial confinement fusion. For the latter, in particular the propagation of compression shocks is crucial. The main unknown in the shock propagation in WDM is the behavior of the electrons since they are governed by correlations, quantum and spin effects that need to be accounted for simultaneously. Here we describe the shock dynamics of the warm dense electron gas using a quantum hydrodynamic model. From the numerical hydrodynamic simulations we observe that the quantum Bohm pressure induces shear force which weakens the formation and strength of the shock.
In addition, the Bohm pressure induces an electron density response which takes the form of oscillations. This is confirmed by the theoretical analysis of the early stage of the shock formation. Our theoretical and numerical analysis allows us to identify characteristic dimensionless shock propagation parameters at which the effect of the Bohm force is important.

Keywords: warm dense matter; shock propagation; quantum hydrodynamics

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Data: A particle-based approach to predict the success and selectivity of leaching processes

Winardhi, C. W.; Da Assuncao Godinho, J. R.; Gutzmer, J.; Rachmawati, C.

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https://doi.org/10.1016/j.hydromet.2022.105869

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Permalink: https://www.hzdr.de/publications/Publ-33699
Publ.-Id: 33699


An ontology for modelling the social, spatial, and semantic relations in pre-modern written sources: Takeaways from data model development in the Dissident Networks Project (DISSINET)

Zbíral, D.; Mertel, A.; Shaw, R.; Hampejs, T.

The extent of data collection in computational history is often delimited by the specific
hypotheses that drive the research in question. Such a parsimonious approach is completely
logical and in many cases sufficient; moreover, there is no such thing as “total” data
collection, because the data is to a degree in the eye of the beholder. At the same time,
however, historical research has a tried and tested tradition of more source-driven research,
where the close reading of sources often drives the direction of study more than the testing
of hypotheses. In this paper, we present our experience of developing a thorough data model
and user interface for the collection of structured data from medieval inquisitorial registers,
focusing mainly on the social, spatial, and semantic relations between historical actors,
groups, places, physical objects, concepts, and events. We undertook this as part of a
project that seeks to provide a networked perspective on religious dissent and its repression
in medieval Europe (Dissident Networks Project / DISSINET, https://dissinet.cz). In this
paper, we would like to discuss our data model and data collection practices as well as to
open the data model to suggestions on how it can be mapped upon existing standards in
order to enhance its interoperability.
From our experience, we derive several proposals which could be of interest to historians
who, on the continuous scale between hypothesis-driven and source-driven data collection,
lean somewhat more towards the latter. Our point of departure is that a data model for
source-driven data collection should allow as much relational complexity as the natural
language of our sources does. Our approach is not completely new from a conceptual or
technical point of view; it is based on statements composed of predicates and actants
(subjects and objects), and therefore close to the idea of “semantic triples”. However, we dig
quite deeply into the language of our sources to propose a way of recording its minutiae,
allowing for fuzziness and uncertainty, modifiers (e.g., adjectives, adverbs), temporal and
spatial relations (incl. relative chronology), modality (negative, question, possibility,
desirability etc.), and give specific meaning to the different actant positions (subject, objects)
of each verb for analytical purposes. We thus join the minority strand in current
computational history which departs from the idea of factoids, decided upon at the moment of
data collection, and rather translate the source into structured data quite extensively to later
adapt the specific data projections to the needs of particular research questions and
hypotheses we want to test.
This approach allows us to preserve the semantic structure and detail of the sources, while
also producing highly structured data suited to various kinds of computational analyses such
as social network analysis, socio-semantic network analysis, geospatial data analysis,
various regression models, etc. Data collection (or rather, production), in our view, thus
already amounts to computational modelling – i.e., in the first instance, we model the source
itself, preserving its original language, its vagaries, and its complexity, and only at a later
stage various research problems in our focus.
The talk does not focus so much on technical solutions (e.g., review of available data
collection environments) or standards. Rather, we explore conceptual issues and a practical
workflow that we believe can be inspirational for computational history more generally.
Nevertheless, the paper includes a brief demonstration of the inkVisitor software, a webbased open-source data collection environment currently under development in our project.

Keywords: historical data; ontologies; textual analysis

  • Open Access Logo Lecture (Conference) (Online presentation)
    Data for History. Modelling Time, Places, Agents, 19.05.-30.06.2021, Berlin, Germany

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Permalink: https://www.hzdr.de/publications/Publ-33698
Publ.-Id: 33698


Current practice in proton therapy delivery in adult cancer patients across Europe

Tambas, M.; van der Laan, H.; Steenbakkers, R.; Doyen, J.; Timmermann, B.; Orlandi, E.; Hoyer, M.; Haustermans, K.; Georg, P.; Burnet, N.; Gregoire, V.; Calugaru, V.; Troost, E. G. C.; Hoebers, F.; Calvo, F.; Widder, J.; Eberle, F.; van Vulpen M, .; Maingon, P.; Skóra, T.; Weber, D.; Bergfeldt, K.; Kubes, J.; Langendijk, J.

Background and purpose

Major differences exist among proton therapy (PT) centres regarding PT delivery in adult cancer patient. To obtain insight into current practice in Europe, we performed a survey among European PT centres.
Materials and methods

We designed electronic questionnaires for eight tumour sites, focusing on four main topics: 1) indications and patient selection methods; 2) reimbursement; 3) on-going or planned studies, 4) annual number of patients treated with PT.
Results

Of 22 centres, 19 (86%) responded. In total, 4,233 adult patients are currently treated across Europe annually, of which 46% consists of patients with central nervous system tumours (CNS), 15% head and neck cancer (HNC), 15% prostate, 9% breast, 5% lung, 5% gastrointestinal, 4% lymphoma, 0.3% gynaecological cancers. CNS are treated in all participating centres (n=19) using PT, HNC in 16 centres, lymphoma in 10 centres, gastrointestinal in 10 centres, breast in 7 centres, prostate in 6 centres, lung in 6 centres, and gynaecological cancers in 3 centres. Reimbursement is provided by national health care systems for the majority of commonly treated tumour sites. Approximately 74% of centres enrol patients for prospective data registration programs. Phase II-III trials are less frequent, due to reimbursement and funding problems. Reasons for not treating certain tumour types with PT are lack of evidence (30%), reimbursement issues (29%) and/or technical limitations (20%).
Conclusion

Across European PT centres, CNS tumours and HNC are the most frequently treated tumour types. Most centres use indication protocols. Lack of evidence for PT and reimbursement issues are the most reported reasons for not treating specific tumour types with PT.

Keywords: Proton therapy; adult patients; patient selection; model-based approach; reimbursement; clinical studies; Europe

Permalink: https://www.hzdr.de/publications/Publ-33697
Publ.-Id: 33697


Sputter Deposited Magnetostrictive Layers for SAW Magnetic Field Sensors

Thormählen, L.; Seidler, D.; Schell, V.; Munnik, F.; McCord, J.; Meyners, D.

For the best possible limit of detection of any thin film‐based magnetic field sensor, the functional magnetic film properties are an essential parameter. For sensors based on magnetostrictive layers, the chemical composition, morphology and intrinsic stresses of the layer have to be controlled during film deposition to further control magnetic influences such as crystallographic effects, pinning effects and stress anisotropies. For the application in magnetic surface acoustic wave sensors, the magnetostrictive layers are deposited on rotated piezoelectric single crystal substrates. The thermomechanical properties of quartz can lead to undesirable layer stresses and associated magnetic anisotropies if the temperature increases during deposition. With this in mind, we compare amorphous, magnetostrictive FeCoSiB films prepared by RF and DC magnetron sputter deposition. The chemical, structural and magnetic properties determined by elastic recoil detection, X‐ray diffraction, and magneto‐optical magnetometry and magnetic domain analysis are correlated with the resulting surface acoustic wave sensor properties such as phase noise level and limit of detection. To confirm the material properties, SAW sensors with magnetostrictive layers deposited with RF and DC deposition have been prepared and characterized, showing comparable detection limits below 200 pT/Hz(^1/2) at 10 Hz. The main benefit of the DC deposition is achieving higher deposition rates while maintaining similar low substrate temperatures.

Keywords: Magnetron Sputter Deposition; FeCoSiB; ERDA; XRD; film stress; magnetic field sensor; magnetic prop

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Permalink: https://www.hzdr.de/publications/Publ-33696
Publ.-Id: 33696


3D Imaging Analysis of Mineral Dissolution to Optimize Environmental Friendly Leaching of Metals

Rachmawati, C.

Leaching using deep eutectic solvent (DES) can be an alternative solution for environmentally friendly leaching. Two choline chloride (ChCl) based DESs are investigated using two different oxidants for each DES, which are ChCl-ethylene glycol and ChCl-lactic acid with iodine (I2) or hydrogen peroxide (H2O2) as the oxidants. This study attempts a new method of determining leaching dissolution rate by using 3D image analysis from single particle leaching experiment to optimize leaching process through time. X-ray computed tomography (CT) is used to scan the particle to get 3D images, volume and surface area of the particle before and after the leaching. Gold, silver and telluride minerals are used as the target minerals, whereas galena, chalcopyrite and pyrite are used as the gangue minerals. The dissolution rate of these minerals calculated from the 3D image processing are then combined with mineral liberation analysis (MLA) data of a sulphide concentrate. This MLA data provides mineralogical characteristic along with scanning electron microscopy (SEM)-based image to be used in leaching simulation to get mineral recoveries. This method shows that selectivity of each target and gangue mineral dissolution in different solution can be observed and compared. The dissolution rate can also be applied in predicting leaching using different characteristic of ores or concentrates. Batch leaching experiments using all the leaching solutions are also done to compare the leaching simulation result.

Keywords: 3D images; X-ray computed tomography; mineral dissolution; selectivity; deep eutectic solvent; mineral leaching; simulation

  • Master thesis
    TU Bergakademie Freiberg, 2021

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Publ.-Id: 33695


Machine learning-based air quality simulations over the United States under multiple climate change scenarios

Fan, K.; Lee, Y. H.

Air quality regulations have reduced emissions of pollutants in the U.S., but many prognostic studies suggest that future air quality might be degraded by global climate change. The simulated climate by various climate models shows a large variation in the future decades, and it is important to account for such variations to study future air quality. A typical approach to study future air quality projections uses three-dimensional (3D) Eulerian models, but these models are computationally too expensive to perform an ensemble of long-term simulations for various climate projections. Therefore, we have developed a machine learning (ML) based air quality model to study, in an efficient way, how future air quality might be influenced by climate change. Our ML model uses two-phase random forest to predict the O3 and PM2.5 concentrations with training datasets of key meteorological information and air quality pollutant emissions. To evaluate the model performance, we used the input datasets for the U.S. Environmental Protection Agent (EPA) the Community Multiscale Air Quality Modeling System (CMAQ) simulations and compared our model predictions against the CMAQ output as a benchmark. The 1995 – 1997 data were used to train the ML model; 2025 – 2035 data were used to evaluate it. The ML model is well performed for hourly O3 predictions over the whole domain in four selected months (January, February, July, and August), and the R2 values are in 0.5 – 0.7, the normalized mean bias (NMB) values are within ±3%, the overall normalized mean error (NME) values are below 20%. Compared to CMAQ, our ML model tends to overpredict the O3 in the Southeast U.S and California, and underpredict in the Central U.S, and the NMB values computed for each grid are generally within ±10%. Predicting PM2.5 is more challenging than predicting O3, but our ML model performance is still acceptable. The overall R2 values of PM2.5 predictions are in 0.4 – 0.6, and the NMB values are within ±6%, but the NME can be up to 60%. The NMB in each grid is within ±30%. There is no clear trend for the regional variation of ML model performance for PM2.5. Our ML model performs better for summer PM2.5 (July and August) than winter (January and February): NME is 10% - 20% lower in summer. While the model performs better in winter than summer with about 10% lower NME for O3. Our ML model with GPU acceleration runs less than one hour using a single GPU processor to predict 11-year one-month (total 11 months) simulations. It uses significantly less computing resources compared to the 3D models, like CMAQ, while it results in comparable predictability to CMAQ. It shows that our ML model a reliable and efficient tool to assess the air quality under various climate change scenarios.

  • Lecture (Conference) (Online presentation)
    ML@HZDR Symposium 2021, 06.12.2021, Görlitz, Germany

Permalink: https://www.hzdr.de/publications/Publ-33693
Publ.-Id: 33693


Comparing different analytical techniques for the characterization of alloys for a possible sensor sorting approach

Ebert, D.; Möckel, R.; Seidel, P.; Raatz, S.

The so called down cycling effect denotes the unwanted mixing of different materials in the recycling stream resulting in materials with lower quality and functionality than the single parts that where introduced to the recycling process. In a project dealing with different analytical methods a sensor strategy for a desired sorting technique was tested. The methods that were applied on different alloys including steel samples, brass and aluminium included: X-ray fluorescence techniques (handheld XRF, WDXRF), laser induced breakdown spectroscopy (LIBS), and spark-OES but also neutron activation.
Spark-OES was used as benchmark, which was verified by using certified reference materials, suitable for the alloys we investigated. The actual tests were done on nine different, commercially available test alloys with known compositions (given ranges of elemental concentrations, though). Initially, they were tested for homogeneity using spatially resolved EDXRF measurements. Deviations to the mean composition were generally lower than 0.2 wt.%. Nevertheless few inhomogeneities were found including impurities and general inhomogenous areas which are attributed to quality issues during manufacturing (probably with no effect on the desired function).
Summarizing the results of this comparative study, it turned out that for specific elements-matrix combinations, like e.g. Si in steels and Cu in Al alloys, LIBS show more accurate results, whereas the XRF techniques exhibit better performances for the main metal quantification due to its direct quantification of the main element (Seidel et al. 2021). Besides the main elements, we tested for Al, Fe, Cu, Si, Mn, Mg, Cr, Ni, Zn depending on the alloy type.
The results were used to simulate a first approximation on a possible sorting result of real scrap metal samples derived from a magnetic separated fraction, on which we applied LIBS, pXRF and WDXRF. These preliminary calculation considered the analytical deviation, different chemical compositions and the elements of interest vs. analytical method.

References:

Seidel, P., Ebert, D., Schinke, R., Möckel, R., Raatz, S., Chao, M., Niederschlag, E., Kreschel, T., Gloaguen, R., Renno, A. D. (2021). Comparison of Elemental Analysis Techniques for the Characterization of Commercial Alloys. Metals, 11(5), 736.

  • Poster
    AOFKA - Applied Surface and Solid State Analytics, 06.-08.10.2021, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33692
Publ.-Id: 33692


Developing methods to tackle analytical issues in battery recycling materials using SEM and bulk analytical methods

Möckel, R.; Bachmann, K.; Vanderbruggen, A.; Ebert, D.

To close the loop of the respective material demands, the role of battery recycling is steadily increasing, especially in the light of changing mobility. The analytical requirements for the battery material are challenging, since they are complex and heterogeneous secondary materials. They contain Li in different compounds, carbon in the form of graphite (“black mass”), but also metals like Mn, Fe, Cu, Al, Co, Ni etc. partly in several oxidation states (pure metal foils vs. different compounds). All these components are also highly affected by the recycling stages (e.g. pyrolysis, leaching, ect.). On the other hand, with the main aim of an effective recycling the demand for as detailed as possible analytical data is likewise high. Generally, there is no single method available for tackling all the analytical issues and a combination of methods is inevitable. In different recycling projects, we developed methods for scanning electron microscope (SEM) techniques (in our case MLA mineral liberation analyser and TIMA Tescan integrated mineral analyzer), quantitative XRD (X-ray diffraction) and XRF (X-ray fluorescence) with support of ICP-OES.
While SEM techniques are essential to provide information on a particle base (incl. chemical composition, grain size, liberation etc.) the other techniques provide pure bulk chemical analytics. An approach – with slight amendments – known from the so called automated mineralogy applied to the materials revealed very useful results for understanding processing parameters, i.e. for the beneficiation of black mass in high quality (Vanderbruggen et al. 2021). On the other hand by simply adding an internal standard (we chose ZrO2) it is possible to develop a quick and easy method for XRF analysis where the sum of “invisible” elements (e.g. C, Li, O, F) can be determined easily with accurate quantification of the other elements, mainly focusing on the metal contents. Lithium containing compounds can be detected by XRD, but the methods have some drawbacks when it comes e.g. to the pure metal contents.
Therefore, a combination of these different approaches helps to increase the analytical precision in order to develop efficient recycling strategies.
References:
Vanderbruggen, A., Gugala, E., Blannin, R., Bachmann, K., Serna-Guerrero, R., & Rudolph, M. (2021). Automated mineralogy as a novel approach for the compositional and textural characterization of spent lithium-ion batteries. Minerals Engineering, 169, 106924.

  • Poster
    AOFKA - Applied Surface and Solid State Analytics, 06.-08.10.2021, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33691
Publ.-Id: 33691


A machine learning-based air quality forecast system for Pacific Northwest

Fan, K.; Dhammapala, R.; Harrington, K.; Lamastro, R.; Lamb, B.; Lee, Y. H.

Chemical transport models (CTMs) are widely used for air quality forecasts but require heavy computational burden and often suffer from a systematic bias that leads to missed poor air pollution events. In this research, we developed a machine learning (ML) modeling framework to provide O3 and PM2.5 forecasts at the monitoring sites throughout the Pacific Northwest (PNW). We used the historical archives from the Weather Research and Forecasting (WRF) meteorological model forecasts, and Air Quality System (AQS) observation datasets of O3 and PM2.5 to build a reliable forecasting system that consists of two ML models, ML1 and ML2: ML1 uses the random forest (RF) classifier and multiple linear regression (MLR) models, and ML2 uses a two-phase RF regression model with best-fit weighting factors. The 10-time, 10-fold cross-validation analysis is used to evaluate our ML forecasting system. Compared to the air quality forecasts based on a CTM, ML1 improves forecast skill for mid-to-high O3 events, which captures 77% more unhealthy events, while ML2 improves forecast skill for low-to-mid O3 events (R2 = 0.78). For PM2.5, our ML model performs well regardless of a season and captures 70% more summer and 30% more winter high-PM2.5 events while the CTM shows systematic biases during summer and winter: 31% underprediction during summer and 5.1% overprediction during winter. The ML modeling framework is now used as an operational forecast of O3 and PM2.5 at the monitoring sites in the PNW.

  • Lecture (Conference) (Online presentation)
    ML for Earth System Modelling and Analytics workshop 2021, 03.-04.05.2021, Görlitz, Germany

Permalink: https://www.hzdr.de/publications/Publ-33690
Publ.-Id: 33690


openPMD A FAIR, self-describing standard for particle-mesh data for the Exascale era

Pöschel, F.; Hübl, A.

openPMD is a community meta-data standard for self-describing, FAIR and compatible exchange of scientific data on top of modern file formats.

The openPMD-api has successfully established an ADIOS2 implementation for efficient and scalable I/O and recently stabilized support for streaming features of ADIOS2. This talk evaluates two use cases for the SST engine in scientific simulation workflows with an I/O stack built by openPMD-api and ADIOS2. The first use case aims for an ad-hoc implementation of asynchronous IO, while the second use case discusses a loosely coupled simulation-analysis workflow with massive data exchange, both evaluated on Summit using the Infiniband network (RDMA).

Keywords: high-performance computing; big data; ADIOS; openPMD; streaming; RDMA

  • Invited lecture (Conferences) (Online presentation)
    Workflow Systems Group Seminar, 22.07.2021, Oak Ridge, USA

Permalink: https://www.hzdr.de/publications/Publ-33689
Publ.-Id: 33689


DIGISORT – Digitally improved sorting of LIB

Kaas, A.; Mütze, T.; Peuker, U. A.

Digitalisation is an important tool to develop and improve industrial processes. The collection and storage of detailed information have to be especially implemented with regard to modern recycling technologies in the field of lithium-ion battery (LIB) processing. Here, real-time recording should enable quick adjustments of the processing parameters and thus improve the process results and product qualities.
The DIGISORT project is part of the greenBatt research cluster which examines heuristically LIB recycling. The project itself focusses on the digitalisation of the mechanical separation via air flow sorting by implementing new sensor technology. Through separation, the components and valuables of lithium-ion batteries have to be transferred into concentrates of high qualities and high recovery rates. In detail, the feed material in air flow sorting is a mixture of electrode foils which is contaminated with other material fractions. Depending on the types of batteries processed and the previous processing steps and parameters, the properties of the mixture vary in size, mass, degree of liberation and composition. As a result, stationary conditions rarely apply in battery recycling and challenge the following separation processes.
A unique sensor technology is developed in DIGISORT recording the most important properties of the material in-line and on-line considering individually each fragment (particle) discretely. Image data with spectroscopic or hyperspectral information will be combined on particle level. Due to the enormous depth of information, these data sets will be structured as information vector for each particle. The control of the air flow sorting using the information vector is intended to increase the separation efficiency and thus the product quality and yield of the aluminium and copper concentrates.
The present contribution introduces the broadness of material characteristics in LIB recycling. Different model mixtures as well as real recycling materials are characterised with regard to their size, shape and composition using a SOPAT camera. These off-line generated data serve as a comparison for the sensor technology to be developed in DIGISORT. In addition to characterisation of the feed material, the camera will be used to describe the separation products and process efficiency.

Keywords: Lithium-ion batteries; recycling

  • Poster
    International Battery Production Conference 2021, 01.-02.11.2021, Braunschweig, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33688
Publ.-Id: 33688


Integration of OPC UA at ELBE

Zenker, K.; Steinbrück, R.; Kuntzsch, M.

The Electron Linac for beams with high Brilliance and low Emittance (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is in operation since 2001. It is operated using the SCADA system WinCC by Siemens. The majority of ELBE systems is connected to WinCC via industrial Ethernet and proprietary S7 communication. However, in recent years new subsystems had to be integrated into the existing infrastructure, which do not provide S7 communication interfaces. Instead, OPC UA has been chosen for system integration. We will show how we use OPC UA as a common communication layer between industrial and scientific instruments as well as proprietary and open source control system software. For example, OPC UA support has been implemented for the ChimeraTK framework developed at DESY. ChimeraTK is used at ELBE e.g. for integrating MicroTCA.4 based subsystems like the digital LLRF system. Furthermore, we are developing a machine data interface for ELBE users. In combination with a certification authority, which hands out user certificates for data access, external users can gain read and write access to different ELBE subsystem data provided by a single OPC UA server.

Keywords: OPC UA; MicroTCA

Related publications

  • Poster (Online presentation)
    18th International Conference on Accelerator and Large Experimental Physics Control Systems, 14.-22.10.2021, Shanghai, China
  • Open Access Logo Contribution to proceedings
    18th Int. Conf. on Acc. and Large Exp. Physics Control Systems, 14.-22.10.2021, Shanghai, China
    Integration of OPC UA at ELBE: JACoW Publishing, 978-3-95450-221-9, 400-404
    DOI: 10.18429/JACoW-ICALEPCS2021-TUPV010

Permalink: https://www.hzdr.de/publications/Publ-33687
Publ.-Id: 33687


Transitioning from file-based HPC workflows to streaming data pipelines with openPMD and ADIOS2

Pöschel, F.; Hübl, A.; E, J.; Godoy, W. F.; Podhorszki, N.; Klasky, S.; Eisenhauer, G.; Davis, P. E.; Wan, L.; Gainaru, A.; Gu, J.; Koller, F.; Widera, R.; Bussmann, M.

This paper aims to create a transition path from file-based IO to streaming-based workflows for scientific applications in an HPC environment. By using the openPMP-api, traditional workflows limited by filesystem bottlenecks can be overcome and flexibly extended for in situ analysis.
The openPMD-api is a library for the description of scientific data according to the Open Standard for Particle-Mesh Data (openPMD).
Its approach towards recent challenges posed by hardware heterogeneity lies in the decoupling of data description in domain sciences, such as plasma physics simulations, from concrete implementations in hardware and IO.
The streaming backend is provided by the ADIOS2 framework, developed at Oak Ridge National Laboratory.
This paper surveys two openPMD-based loosely-coupled setups to demonstrate flexible applicability and to evaluate performance.
In loose coupling, as opposed to tight coupling, two (or more) applications are executed separately, e.g. in individual MPI contexts, yet cooperate by exchanging data. This way, a streaming-based workflow allows for standalone codes instead of tightly-coupled plugins, using a unified streaming-aware API and leveraging high-speed communication infrastructure available in modern compute clusters for massive data exchange.
We determine new challenges in resource allocation and in the need of strategies for a flexible data distribution, demonstrating their influence on efficiency and scaling on the Summit compute system.
The presented setups show the potential for a more flexible use of compute resources brought by streaming IO as well as the ability to increase throughput by avoiding filesystem bottlenecks.

Keywords: high performance computing; big data; streaming; RDMA; openPMD; ADIOS

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    Smoky Mountains Computational Sciences & Engineering Conference (SMC2021), 18.-20.10.2021, Oak Ridge, USA
  • Open Access Logo Contribution to proceedings
    Smoky Mountains Computational Sciences & Engineering Conference (SMC2021), 18.-20.10.2021, Oak Ridge, USA
    Communications in Computer and Information Science, Volume 1512 CCIS, 99-118
    DOI: 10.1007/978-3-030-96498-6_6
    Cited 2 times in Scopus

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Permalink: https://www.hzdr.de/publications/Publ-33686
Publ.-Id: 33686


Influence of cell opening methods on organic solvent removal during pretreatment in lithium-ion battery recycling

Werner, D. M.; Mütze, T.; Peuker, U. A.

The use and development of lithium-ion batteries (LIBs) are promoting the technological transformation of individual mobility, consumer electronics and electric energy storage. At their end of life, the complex compounds are disposed by different recycling technologies with defined secondary raw material production. The applied depollution temperatures of the process routes influence not only the recycling efficiency but also the process expenditure, design, medium and costs. Different pretreatment strategies in terms of dismantling depth and depollution temperature are existing. Furthermore, manual and mechanical methods for cell opening are distinguished, which together with the depollution leads to a respective organic solvent evaporation. In this contribution to LIB recycling, the influence of different dismantling depths, achieved by manual cell opening, on the thermal depollution of the LIB cells regarding the mass difference originating by organic solvent evaporation are quantified, in order to determine cell and equipment properties for a safe cell opening. As a result, combinations of thermal depollution and manual cell opening are discussed regarding technical and economic feasibility. The process medium and equipment properties for a safe cell opening are determined. Furthermore, recommendations for future industrial LIB waste management are presented.

Keywords: Pre-treatment; depollution; dismantling; Lithium-ion batteries; recycling; thermal drying; Electronic Waste; Evaporation; Organic solvents

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Permalink: https://www.hzdr.de/publications/Publ-33685
Publ.-Id: 33685


Validation of a morphology-adaptive hybrid model for a vane-type gas-liquid separator

Zhang, T.; Liao, Y.; Krull, B.; Lucas, D.; Yin, J.; Wang, D.

In light of the flow regime transition (bubbly flow to stratified) phenomenon occurring in the vane-type gas-liquid separator, a morphology-adaptive hybrid model featuring with multi fields is applied to predict the complex dynamic behaviors of interfacial structures in it. By means of this model, the coexistence of dispersed bubbles and continuous gas core is able to be described simultaneously with the same set of equations. One key issue related to the simulation of the multi-scale interfacial structure in the separator is the morphology transition criterion, more specifically, the formation of continuous gas out from dispersed gas. A preliminary transition criterion combining coalescence transfer and absorption transfer based on local volume fraction of the dispersed gas and the continuous gas has been implemented in the multi-field Eulerian two-fluid framework. Several simple swirling flow cases are adopted to test its performance and evaluate the effects of key model parameters. The capability of the new hybrid model representing both bubbly flow and continuous gas core as well as their transition is verified for a vane-type separator under two circumstances, namely, the stable gas core and the unstable gas core. For both cases, the numerical results present high similarities with the experimental results, which suggest that the hybrid model is capable of capturing the complex gas-core behavior in the vane-type gas liquid separator and serving as a reliable numerical predicting tool.

Keywords: gas core instability; multi-scale interface; multi-field simulation; swirling flow; openfoam

  • Poster (Online presentation)
    18th Multiphase Flow Conference & Short Course, 08.-12.11.2021, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-33684
Publ.-Id: 33684


Invertible Surrogate Models: Joint surrogate modelling and reconstruction of Laser-Wakefield Acceleration by invertible neural networks

Bethke, F.; Pausch, R.; Stiller, P.; Debus, A.; Bussmann, M.; Hoffmann, N.

Invertible neural networks are a recent technique in machine learning promising neural network architectures that can be run in forward and reverse mode. In this paper, we will be introducing invertible surrogate models that approximate complex forward simulation of the physics involved in laser plasma accelerators: iLWFA. The bijective design of the surrogate model also provides all means for reconstruction of experimentally acquired diagnostics. The quality of our invertible laser wakefield acceleration network will be verified on a large set of numerical LWFA simulations.

Keywords: Plasma Physics; Machine Learning; Accelerator Physics

  • Open Access Logo Contribution to proceedings
    ICLR 2021 - Ninth International Conference on Learning Representations, 03.-07.05.2021, Vienna, Austria
    Deep Learning for Simulation (SimDL) Workshop

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Permalink: https://www.hzdr.de/publications/Publ-33683
Publ.-Id: 33683


Development of a Machine Learning Approach for Local-Scale Ozone Forecasting: Application to Kennewick, WA

Fan, K.; Dhammapala, R.; Harrington, K.; Lamastro, R.; Lamb, B.; Lee, Y. H.

Chemical transport models (CTMs) are widely used for air quality forecasts, but these models require large computational resources and often suffer from a systematic bias that leads to missed poor air pollution events. For example, a CTM-based operational forecasting system for air quality over the Pacific Northwest, called AIRPACT, uses over 100 processors for several hours to provide 48-h forecasts daily, but struggles to capture unhealthy O3 episodes during the summer and early fall, especially over Kennewick, WA. This research developed machine learning (ML) based O3 forecasts for Kennewick, WA to demonstrate an improved forecast capability. We used the 2017–2020 simulated meteorology and O3 observation data from Kennewick as training datasets. The meteorology datasets are from the Weather Research and Forecasting (WRF) meteorological model forecasts produced daily by the University of Washington. Our ozone forecasting system consists of two ML models, ML1 and ML2, to improve predictability: ML1 uses the random forest (RF) classifier and multiple linear regression (MLR) models, and ML2 uses a two-phase RF regression model with best-fit weighting factors. To avoid overfitting, we evaluate the ML forecasting system with the 10-time, 10-fold, and walk-forward cross-validation analysis. Compared to AIRPACT, ML1 improved forecast skill for high-O3 events and captured 5 out of 10 unhealthy O3 events, while AIRPACT and ML2 missed all the unhealthy events. ML2 showed better forecast skill for less elevated-O3 events. Based on this result, we set up our ML modeling framework to use ML1 for high-O3 events and ML2 for less elevated O3 events. Since May 2019, the ML modeling framework has been used to produce daily 72-h O3 forecasts and has provided forecasts via the web for clean air agency and public use: http://ozonematters.com/. Compared to the testing period, the operational forecasting period has not had unhealthy O3 events. Nevertheless, the ML modeling framework demonstrated a reliable forecasting capability at a selected location with much less computational resources. The ML system uses a single processor for minutes compared to the CTM-based forecasting system using more than 100 processors for hours.

Keywords: machine learning; air quality forecasts; ozone; random forest; multiple linear regression

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Permalink: https://www.hzdr.de/publications/Publ-33682
Publ.-Id: 33682


The role of transglutaminase 2 in the radioresistance of melanoma cells

Aepler, J.; Wodtke, J.; Wodtke, R.; Haase-Kohn, C.; Löser, R.; Pietzsch, J.; Hauser, S.

Transglutaminase 2 (TG2) is a protein expressed in many tissues that exerts numerous, some-times contradictory intra- and extracellular functions under both physiological and pathophysi-ological conditions. In the context of tumor progression, it has been found to be involved in cell adhesion, DNA repair mechanisms, the induction of apoptosis, and mesenchymal transdifferen-tiation, among others. Here, we hypothesized that TG2 also contributes to the radioresistance of two human melanoma cell lines A375 and MeWo which differ in their basal TG2 biosynthesis by examining their proliferation and clonal expansion after irradiation. For this purpose, cellular TG2 biosynthesis and TG2 activity were modulated by transfection-induced overexpression or TG2 knock-out and application of TG2-selective inhibitors. Proliferation and clonal expansion of TG2-overexpressing cells was not enhanced over wildtype cells, suggesting that increased TG2 biosynthesis does not further enhance the radioresistance of melanoma cells. Conversely, TG2 knock-out in A375 cells reduced their clonal and spheroidal expansion after irradiation, which indicates a contribution of TG2 to the radioresistance of melanoma cells. Since TG1, TG3, and partly also TG6 biosynthesis was detectable in A375 and MeWo cells, it can be assumed that these other members of the TG family may exert a partially compensatory effect.

Keywords: Clonal expansion; fluorescence anisotropy assay; malignant melanoma; tumor radioresistance; TG2 inhibition

Permalink: https://www.hzdr.de/publications/Publ-33681
Publ.-Id: 33681


Impact of Sodium Hexametaphosphate on the Flotation of Ultrafine Magnesite from Dolomite-Rich Desliming Tailings

Hoang, D. H.; Ebert, D.; Möckel, R.; Rudolph, M.

The depletion of ore deposits, the increasing demand for raw materials, the need to process low-grade, complex and finely disseminated ores, and the reprocessing of tailings are challenges especially for froth flotation separation technologies. Even though they are capable of handling relatively fine grain sizes, the flotation separation of very fine and ultrafine particles faces many problems still. Further, the flotation of low-contrast semi-soluble salt-type minerals with very similar surface properties, many complex interactions between minerals, reagents and dissolved species often result in poor selectivity. This study investigates the flotation beneficiation of ultrafine magnesite rich in dolomite from desliming, currently reported to the tailings. The paper especially focuses on the impact of the depressant sodium hexametaphosphate (SHMP) on the following: (i) the froth properties using dynamic froth analysis (DFA), (ii) the separation between magnesite and dolomite/calcite, and (iii) its effect on the entrainment. As a depressant/dispersant, SHMP has a beneficial impact on the flotation separation between magnesite and dolomite. However, there is a trade-off between grade and recovery, and as well as the dewatering process which needs to be considered. When the SHMP increases from 200 g/t to 700 g/t, the magnesite grade increases from 67% to 77%, while recovery decreases massively, from 80% to 40%. The open circuit with four cleaning stages obtained a concentrate assaying 77.5% magnesite at a recovery of 45.5%. The dolomite content in the concentrate is about 20%, where 80% of dolomite was removed and importantly 98% of the quartz was removed, with only 0.3% of the quartz in the final concentrate. Furthermore, the application of 1-hydroxyethylene-1,1-diphosphonic acid (HEDP) as a more environmentally friendly and low-cost alternative to SHMP is presented and discussed. Using only 350 g/t of HEDP can achieve a similar grade (76.3%), like 700 g/t of SHMP (76.9%), while obtaining a 17% higher magnesite recovery as compared to 700 g/t of SHMP. Interestingly, the proportion of hydrophilic quartz minerals ending up in the concentrate is lower for HEDP, with only 1.9% quartz at a recovery of 21.5% compared to the 2.7% of quartz at a recovery of 24.9% when using SHMP. The paper contributes in general to understanding the complexity of the depressant responses in froth flotation.

Keywords: magnesite; dolomite; tailings; sodium hexametaphosphate SHMP; 1-hydroxyethylene-1,1- diphosphonic acid HEDP; dynamic froth analyzer; froth properties; remining; pneumatic Imhoflot; reactor–separator

Permalink: https://www.hzdr.de/publications/Publ-33679
Publ.-Id: 33679


Recovery of REEs as co-products from a Vietnamese sedimentary phosphate ore by flotation - Impact of milling conditions

Hoang, D. H.; Balinski, A.; Kupka, N.; Möckel, R.; Kelly, N.; Rudolph, M.

Vietnamese phosphate deposits are of marine sedimentary origin and one of the largest phosphate rock deposits of Southeast Asia. Lao Cai phosphate reserves have been estimated at about 526 million tonnes with hypothetical reserves of about 2.6 billion tonnes. Phosphate rock has been considered as a secondary rare earth elements (REEs) source due to REEs often found as tracers of geochemical processes in the crystal structure of phosphates via substitution of Ca. Although the content of REEs in apatite is rather low, it is still relevant by total mass due to large tonnages of phosphate rock mined annually.
The impact of milling conditions on particle properties, pulp/ froth properties (Ca2+/ Mg2+ ion concentrations, pulp rheology, froth structure, etc.), which in turn influences on the flotation responses (grade, recovery, flotation kinetics and selectivity between apatite, REEs-bearing apatite and carbonate minerals) are given. With a rougher flotation feed containing about 12 % P2O5 and 200 g/t REEs, the obtained recoveries were 88-93 % for apatite and 75-84 % for REEs. This indicated that REEs can be enriched by froth flotation via co-flotation of the REEs-bearing apatite or true flotation of rare earth bearing minerals. However, there was only 24-29 % of dolomite removed from a feed containing about 7.3 % MgO. Thus, the separation of carbonate from finely disseminated siliceous carbonaceous apatite ores is given to be challenging due to fine intergrowth and a significant amount of dolomite with similar flotation properties like apatite.

  • Contribution to proceedings
    Advances in Metallurgy and Materials Engineering - COM2021, 17.-19.08.2021, Quebec, Canada
    Proceedings of the 60th Conference of Metallurgists 2021, Canada, 978-1-926872-53-7

Permalink: https://www.hzdr.de/publications/Publ-33678
Publ.-Id: 33678


Impact of the grinding conditions on the particle properties and flotation of a scheelite ore

Kupka, N.; Hoang, D. H.; Saquran, S. S. S.; Rudolph, M.

Milling and flotation operations are typically studied separately in the literature, although it is well-established that the grinding environment is a determining factor on the flotation performance. This study aims at evaluating the effect of grinding conditions on the discharge particle properties and the subsequent flotation responses in the specific case of semi-soluble salt-type minerals. Three different ores were used as case studies: a scheelite (low-grade), an apatite (medium-grade) and a fluorite (high grade) ore. All three ores were dry-milled, wet-milled, and wet-milled in presence of depressants down to a particle size distribution specific to each ore, and the mill discharge was then floated under pre-established conditions in an Outotec mechanical cell. The concentrates and tailings of flotation tests were characterized with a Mineral Liberation Analyzer (MLA). This article presents the comparative results of the flotation tests conducted on the scheelite ore based on particle properties including size, composition, liberation, association, entrainment and shape.

Keywords: Grinding environment; Semi-soluble salt-type mineral; Mineral liberation analyzer; Scheelite flotation

  • Lecture (Conference) (Online presentation)
    The 12th International Comminution Symposium (Comminution '21), 19.-22.04.2021, Cape Town, South Africa

Permalink: https://www.hzdr.de/publications/Publ-33677
Publ.-Id: 33677


Data publication: The mechanism behind the high radiation tolerance of Fe-Cr alloys

Agarwal, S.; Butterling, M.; Liedke, M. O.; Yano, K.; Schreiber, D. K.; Jones, A. C. L.; Uberuaga, B. P.; Wang, Y. Q.; Chancey, M.; Kim, H.; Li, N.; Edwards, D. J.; Hosemann, P.; Kaoumi, D.; Hirschmann, E.; Wagner, A.; Selim, F. A.

Positron annihilation data obtained at SPONSOR/AIDA and MePS at ELBE. Data contains DBS and PALS measurements

Keywords: Vacancy clusters; ion-irradiation; Doppler broadening spectroscopy (DBS); positron annihilation lifetime (PALS); atom probe tomography (APT)

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Permalink: https://www.hzdr.de/publications/Publ-33676
Publ.-Id: 33676


The mechanism behind the high radiation tolerance of Fe-Cr alloys

Agarwal, S.; Butterling, M.; Liedke, M. O.; Yano, K.; Schreiber, D. K.; Jones, A. C. L.; Uberuaga, B. P.; Wang, Y. Q.; Chancey, M.; Kim, H.; Li, N.; Edwards, D. J.; Hosemann, P.; Kaoumi, D.; Hirschmann, E.; Wagner, A.; Selim, F. A.

With the great demand for high radiation tolerant materials for advanced nuclear energy technologies, Fe-Cr alloys are at the forefront with long standing validated performance. Yet, the real mechanism behind their high radiation resistance is in question and understanding the effect of varying Cr percentage is a grand challenge limiting further improvements. Here we applied depth resolved atomic scale probe of defects to uncover the real mechanism on how Cr improves radiation resistance and explain the controversial impact of increasing Cr percentage. By combining depth-resolved positron annihilation lifetime spectroscopy and Doppler broadening spectroscopy we investigated the effect of Cr alloying on the formation and evolution of atomic size clusters induced by ion irradiation in Fe. We also used atom probe tomography to investigate the possible presence of Cr clusters or alpha' phase with high Cr composition. The study reveals that the well-known resistance to radiation in Fe-Cr alloys arises from the stabilization of vacancy clusters around Cr atoms which act as sinks for radiation-induced defects. Thus, Cr atoms do not provide a direct sink for interstitials; rather defect complexes for that consist of Cr atoms and vacancies in turn act as sinks for irradiation-induced vacancies and interstitials. Most importantly, we find that lower amounts of Cr create smaller, uniformly distributed defect clusters that act as efficient sinks for radiation damage, but larger quantities of Cr form a defect structure that is less homogenous in size and spatial distribution, resulting in less efficient damage recombination. No evidence of phase alpha’ was found before or after irradiation, which indicates that it does not contribute to the observed radiation tolerance.

Keywords: Vacancy clusters; ion-irradiation; Doppler broadening spectroscopy (DBS); positron annihilation lifetime (PALS); atom probe tomography (APT)

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Permalink: https://www.hzdr.de/publications/Publ-33675
Publ.-Id: 33675


Research data: Grating-graphene metamaterial as a platform for terahertz nonlinear photonics

Deinert, J.-C.; Kovalev, S.; Tielrooij, K.-J.

Research data for used for the publication: "Grating-graphene metamaterial as a platform for terahertz nonlinear photonics".

Datasets measured at the TELBE accelerator-based THz source are measured using a pulse-resolved detection scheme. The data points are sorted according to the absolute arrival time measurement. The four columns hold the following data:
1) absolute time in picoseconds
2) Signal of the emitted THz measured by electro-optic sampling.
3) Relative THz intensity measured using a pyroelectric detector. THz intensity is proportional to absolute power of the signal.
4) Data corresponding to the relative timing of each pulse. Not used for further analysis of the data.

The filenumbers of the measurements used for the figures are as follows:
Fig. 1a: File 003
Fig. 1b-c: File 043
Fig. 1d-e: File 086

Fig. 2a: Files 080..088 (bare graphene) and 031..049 (grating)
Fig. 2b: same

Fig. 3a: Files 050..057
Fig. 3c: Files 076..079

Fig. 4. Table top measurements; no file numbers

Supp. Fig. 2: File 030

Supp. Fig. 4: File 024..025

Supp. Fig. 7a: Files 031..034 and 036..041
Supp. Fig. 7b: Files 080..083
Supp. Fig. 7d: Files 031..049 and 080..086

Supp. Fig. 9a: Files 031..046
Supp. Fig. 9b: Files 080..085 and 087..088

The datasets measured using a table-top laser source contain two columns. The first one is the position of the optical delay stage in mm that has to be multiplied by 6.667 ps/mm to define the time axis. The second column contains the THz signal as measured using electro-optic sampling.

Keywords: Terahertz; Graphene; Ultrafast; Metamaterial; High harmonics

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Permalink: https://www.hzdr.de/publications/Publ-33671
Publ.-Id: 33671


X-ray spectroscopic study of chemical state in uranium carbides

Butorin, S. M.; Bauters, S.; Amidani, L.; Beck, A.; Weiss, S.; Vitova, T.; Tougaite, O.

UC and UMeC2 (Me=Fe, Zr, Mo) carbides were studied by high-energy-resolution fuorescence detected x-ray absorption (HERFD-XAS) technique at the U M4 and L3 edges. Both U M4 and L3 HERFD-XAS of UMeC2 reveal some differences from that of UC and between each other in terms of the spectral width and energy position.
The observed differences are attributed to the consequences of the U 5f; 6d-4d(3d) hybridization in UMeC2. Calculations of the U M4 HERFD-XAS spectra were also performed using the Anderson impurity model (AIM). Based on the analysis of the data, the 5f occupancy in the ground state of UC was estimated to be 3.05 electrons. This fnding is also supported by the analysis of U N4;5 XAS of UC and by the results of the AIM calculations of the U 4f x-ray photoelectron spectrum of UC.

Permalink: https://www.hzdr.de/publications/Publ-33670
Publ.-Id: 33670


Perspective on synthesis, structure, and magnetic properties of R–Fe–H hydrides

Tereshina, I. S.; Pankratov, N. Y.; Karpenkov, A. Y.; Gorbunov, D.; Doerr, M.; Paukov, M. A.; Tereshina-Chitrova, E. A.; Andreev, A. V.

The structural and magnetic properties of the multicomponent R–Fe–H compounds with a high content of Fe and H are reported. The process of synthesis of the hydrides (R,R`)2Fe14BH5.5 [where R and R` are light (Nd) and heavy (Dy, Ho, Er, Tm) rare earth metals, respectively] with a maximum hydrogen content is described in detail. The paper also provides insights into the synthesis of single-crystalline hydrides using the example of the R2(Fe,Co)14BH3 series. The hydrides (R,Nd)2Fe14BH5.5, R2(Fe,Co)14BH3, R2(Fe,Al)17H3 have a significantly increased volume as compared to the parent materials. High-field magnetization results of both parent and hydrogenated compounds at low temperatures are presented. Spin–reorientation phase transitions induced by an external magnetic field are observed. The parameter of the intersublattice exchange interaction and the influence of hydrogen on it are estimated within the framework of the mean field theory. The magnetocaloric effect of the compounds with a magnetic compensation point is studied with a special emphasis placed on the change of the sign of the effect.

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Permalink: https://www.hzdr.de/publications/Publ-33669
Publ.-Id: 33669


Propagation of longitudinal acoustic phonons in ZrTe5 exposed to a quantizing magnetic field

Ehmcke, T.; Galeski, S.; Gorbunov, D.; Zherlitsyn, S.; Wosnitza, J.; Gooth, J.; Meng, T.

The compound ZrTe5 has recently been connected to a charge-density-wave (CDW) state with intriguing transport properties. Here, we investigate quantum oscillations in ultrasound measurements that microscopically originate from electron-phonon coupling and analyze how these would be affected by the presence or absence of a CDW. We calculate the phonon self-energy due to electron-phonon coupling, and from there deduce the sound-velocity renormalization and sound attenuation. We find that the theoretical predictions for a metallic Dirac model resemble the experimental data on a quantitative level for magnetic fields up to the quantum-limit regime.

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Permalink: https://www.hzdr.de/publications/Publ-33668
Publ.-Id: 33668


Cancer stem cells: advances in biology and clinical translation-a Keystone Symposia report

Cable, J.; Pei, D.; Reid, L. M.; Wang, X. W.; Bhatia, S.; Karras, P.; Melenhorst, J. J.; Grompe, M.; Lathia, J. D.; Song, E.; Kuo, C. J.; Zhang, N.; White, R. M.; Ma, S. K.; Ma, L.; Chin, Y. R.; Shen, M. M.; Ng, I. O. L.; Kaestner, K. H.; Zhou, L.; Sikandar, S.; Schmitt, C. A.; Guo, W.; Chak-Lui Wong, C.; Ji, J.; Tang, D. G.; Dubrovska, A.; Yang, C.; Wiedemeyer, W. R.; Weissman, I. L.

The test for the cancer stem cell (CSC) hypothesis is to find a target expressed on all, and only CSCs in a patient tumor, then eliminate all cells with that target that eliminates the cancer. That test has not yet been achieved, but CSC diagnostics and targets found on CSCs and some other cells have resulted in a few clinically relevant therapies. However, it has become apparent that eliminating the subset of tumor cells characterized by self-renewal properties is essential for long-term tumor control. CSCs are able to regenerate and initiate tumor growth, recapitulating the heterogeneity present in the tumor before treatment. As great progress has been made in identifying and elucidating the biology of CSCs as well as their interactions with the tumor microenvironment, the time seems ripe for novel therapeutic strategies that target CSCs to find clinical applicability. On May 19-21, 2021, researchers in cancer stem cells met virtually for the Keystone eSymposium "Cancer Stem Cells: Advances in Biology and Clinical Translation" to discuss recent advances in the understanding of CSCs as well as clinical efforts to target these populations.

Keywords: cancer stem cell; hepatocellular carcinoma; organoids; pluripotent; progenitors; stemness; tumor heterogeneity; tumorigenesis

Permalink: https://www.hzdr.de/publications/Publ-33667
Publ.-Id: 33667


Particle-based characterization of LIB recycling using automated mineralogy

Vanderbruggen, A.

Invited speaker “Particle-based characterization of LIB recycling using automated mineralogy”, 11th Advanced Automotive Battery Conference AABC 2021, online

  • Invited lecture (Conferences) (Online presentation)
    11th Advanced Automotive Battery Conference AABC 2021, online, 19.-21.01.2021, Online, online

Permalink: https://www.hzdr.de/publications/Publ-33666
Publ.-Id: 33666


Graphite a critical and strategic mineral for E-Mobility

Vanderbruggen, A.; Leguérinel, M.; Rudolph, M.

International talk: “Graphite a critical and strategic mineral for E-Mobility” Sustainable Minerals MEI, Online

  • Open Access Logo Lecture (Conference) (Online presentation)
    Sustainable Minerals MEI, 21.-24.06.2021, Online, online

Permalink: https://www.hzdr.de/publications/Publ-33665
Publ.-Id: 33665


Automated mineralogy as a novel method to assess the efficiency of lithium-ion batteries recycling

Vanderbruggen, A.; Gugala, E.; Blannin, R.; Bachmann, K.; Serna-Guerrero, R.; Rudolph, M.

  • Lecture (Conference)
    26th international congress for battery recycling ICBR, 22.-25.09.2021, Geneva, Switzerland

Permalink: https://www.hzdr.de/publications/Publ-33664
Publ.-Id: 33664


Recovery of spheroidized graphite from spent lithium-ion batteries

Vanderbruggen, A.

  • Open Access Logo Lecture (Conference)
    International Battery Production Conference IBPC, 01.-3.11.2021, Braunschweig, Germany

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Permalink: https://www.hzdr.de/publications/Publ-33663
Publ.-Id: 33663


Characterization of the black mass of battery waste

Vanderbruggen, A.

  • Invited lecture (Conferences)
    International Process Metallurgy Symposium IPMS, 09.-10.11.2021, Espoo, Finland

Permalink: https://www.hzdr.de/publications/Publ-33662
Publ.-Id: 33662


Improving separation efficiency in end-of-life lithium-ion batteries flotation using attrition pre-treatment

Vanderbruggen, A.; Salces, A. M.; Ferreira, A.; Rudolph, M.; Serna-Guerrero, R.

The comminution of spent lithium-ion batteries (LIBs) produces a powder containing the active cell components, commonly referred to as “black mass.” Recently, froth flotation has been pro-posed to treat the fine fraction of black mass (< 100µm) as a method to separate anodic graphite particles from cathodic lithium metal oxides (LMOs). So far, pyrolysis has been considered as an effective treatment to remove organic binders in the black mass in preparation for flotation sepa-ration. In this work, the flotation performance of a pyrolyzed black mass obtained from an indus-trial recycling plant was improved by adding a pre-treatment step consisting of mechanical attri-tion. The LMOs recovery in the underflow product increased from 70% to 85% and the graphite recovery remained similar, around 86% recovery in the overflow product. To understand the flo-tation behaviour, the spent black mass was compared to a model black mass, comprising fully lib-erated LMOs and graphite particles. In addition, ultrafine hydrophilic particles were added to the flotation feed as an entrainment tracer, showing that the LMO recovery in overflow products is a combination of entrainment and true flotation mechanisms. This study highlights that adding kerosene during attrition enhance the emulsification of kerosene, simultaneously increasing its (partial) spreading on LMOs, graphite and residual binder, with a subsequent reduction of selectivity.

Keywords: Black mass; spent lithium-ion batteries; graphite; lithium metal oxides; froth flotation; mineral processing; recycling

Permalink: https://www.hzdr.de/publications/Publ-33661
Publ.-Id: 33661


Strongly enhanced growth of high temperature superconducting films on an advanced metallic template

Khan, M. Z.; Rivasto, E.; Rijckaert, H.; Zhao, Y.; Liedke, M. O.; Butterling, M.; Wagner, A.; van Driesche, I.; Huhtinen, H.; Paturi, P.

We demonstrate a straightforward and easily applicable technique for growing the highly improved quality of artificially BaZrO3 doped YBa2Cu3O6+x films on a commercially used buffered metallic template by pulsed laser deposition. Our method relies on reducing the grain size of the target material, which completely prevents the transfer of the harmful grain boundaries or weak links from the substrate through the buffer layers on the deposited film. We have also observed a great improvement in the self-assembly of BaZrO3 dopants and the critical current density is increased in the high temperature range up to 40%. As an extra benefit, our method allows increasing the growth rate of the film by 25%. We have discussed the results comprehensively with the help of the Ginzburg-Landau theory and provided an universal quantitative model of the grain boundary transfer from the substrate to the deposited film. The presented technique can be considered as a groundbreaking advancement for the vastly growing coated conductor industry.

Keywords: YBCO; superconductor; doping; positron annihilation spectroscopy

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Permalink: https://www.hzdr.de/publications/Publ-33660
Publ.-Id: 33660


Characterizing heavy ions-implanted Zr/Nb: structure and mechanical properties

Daghbouj, N.; Sen, H. S.; Čížek, J.; Lorinčík, J.; Karlík, M.; Callisti, M.; Čech, J.; Havránek, V.; Li, B.; Krsjak, V.; Liedke, M. O.; Butterling, M.; Wagner, A.; Polcar, T.

In this work, the radiation responses of Zr/Nb nanostructured metallic multilayers (NMMs) are studied. The nanostructures with different layer thicknesses were deposited on Si (1 0 0)
substrate by using magnetron sputtering and are subjected to heavy-ion irradiation at room temperature with different fluences. Nanoindentation, XRD, SIMS, and Variable Energy
Positron Annihilation Spectroscopy (VEPAS) techniques were used to study the changes in the hardness of the structures as well as the type and distribution of defects, and strain within the material as a function of damage. Our results suggest that the irradiation hardening is independent of the type of implanted ions, and its magnitude decreases with decreasing
individual layer thickness indicating that the number of interfaces has a direct effect on the radiation tolerance enhancement. For thin layers with a periodicity of 27 nm (Zr/Nb27), a
transition from hardening to softening occurs at high fluence, and a saturation point is reached in thick layers with a periodicity of 96 nm (Zr/Nb96). The as-deposited multilayer with the
smaller periodicity experienced a significantly higher atomic-scale disorder which increases with ion irradiation compared to the multilayer with thicker individual layers. VEPAS reveals
the vacancy defects before and after irradiation that contribute to the presented strain. Based on the findings, thin nanostructured Zr/Nb multilayered structures possess excellent radiation
resistance due to the high density of interfaces that act as sinks for radiation-induced point defects.

Keywords: ion irradiation; Zr; Nb; multilayers; positron annihilation spectroscopy; magnetron sputtering

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Permalink: https://www.hzdr.de/publications/Publ-33659
Publ.-Id: 33659


Numerical Simulation of Batteries, Fuel Cells and Electrolysers with OpenFOAM

Weber, N.

The talk will give an overview on the numerical simulation of liquid metal batteries, polymer electrolyte fuel cells and electrolysers. After a brief introduction to liquid metal batteries, different exemplary simulations will be presented - with a focus on the interaction of fluid flow and electrochemistry. The presentation will be limited to the continuum mechanical open-source finite-volume library OpenFOAM.

  • Invited lecture (Conferences)
    Seminar series "Hardware & Numerics", 14.12.2021, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-33658
Publ.-Id: 33658


Phenylarsonic acid–DMPS redox reaction and conjugation investigated by NMR spectroscopy and X-ray diffraction

Kretzschmar, J.; Brendler, E.; Wagler, J.

The reaction between 2,3-dimercaptopropane-1-sulfonate (DMPS, unithiol) and four phenylarsonic(V) acids, i.e. phenylarsonic acid (PAA), 4-hydroxy-3-nitrophenylarsonic acid (HNPAA), 2-aminophenylarsonic acid (o-APAA) and 4-aminophenylarsonic acid (p-APAA), is investigated in aqueous solution. The pentavalent arsenic compounds are reduced by DMPS to their trivalent analogs and instantly chelated by the vicinal dithiol, forming covalent As–S bonds within a five-membered chelate ring. The different types and positions of polar substituents at the aromatic ring of the arsonic acids influence the reaction rates in the same way as observed for reaction with glutathione (GSH), as well as the syn : anti molar ratio of the diastereomeric products, which was analyzed using time- and temperature-dependent nuclear magnetic resonance (NMR) spectroscopy. Addition of DMPS to the conjugate formed by a phenylarsonic(V) acid and the biologically relevant tripeptide GSH showed the immediate replacement of GSH by chelating DMPS, underlining the importance of dithiols as detoxifying agent.

Keywords: Arsenic; Unithiol; DMPS; GSH; Glutathione; Molecular structure; Kinetics; Redox reaction; Chelation; Toxicology

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Permalink: https://www.hzdr.de/publications/Publ-33657
Publ.-Id: 33657


Nested Formation of Calcium Carbonate Polymorphs in a Bacterial Surface Membrane with a graded Nanoconfinement - An Evolutionary Strategy to Ensure Bacterial Survival

Simon, P.; Pompe, W.; Gruner, D.; Sturm (Née Rosseeva), E.; Ostermann, K.; Matys, S.; Vogel, M.; Roedel, G.

It is the intention of this study to elucidate the nested formation of calcium carbonate polymorphs or polyamorphs in the different nanosized compartments. With these observations it can be concluded how the bacteria can survive in a harsh environment with high calcium carbonate supersaturation. The mechanisms of calcium carbonate precipitation at the surface membrane and at the underlying cell wall membrane of the thermophilic soil bacterium Geobacillus stearothermophilus DSM 13240 have been revealed by high-resolution transmission electron microscopy and atomic force microscopy. In this Gram-positive bacterium nanopores in the surface layer (S-layer) and in the supporting cell wall polymers are nucleation sites for metastable calcium carbonate polymorphs and polyamorphs. In order to observe the different metastable forms, various reaction times and a low reaction temperature (4 °C) have been chosen. Calcium carbonate polymorphs nucleate in the confinement of nanosized pores (Ø3-5 nm) of the S-layer. The hydrous crystalline calcium carbonate (ikaite) is formed initially with [110] as the favored growth direction. It transforms into the anhydrous metastable vaterite by a solid-state transition. In a following reaction step calcite is precipitated caused by dissolution of vaterite in the aqueous solution. In the larger pores of the cell wall (Ø 20-50 nm) hydrated amorphous calcium carbonate is grown, which transforms into metastable monohydrocalcite, aragonite or calcite. Due to sequence of reaction steps via various metastable phases the bacteria gain time for chipping the partially mineralized S-layer, and forming a fresh S-layer (characteristic growth time about 20 min). Thus, the bacteria can survive in solutions with high calcium carbonate supersaturation under the conditions of forced biomineralization.

Keywords: S-layer; peptidoglycan layer; nanostructures; calcium carbonate; forced biomineralization; HR-TEM

Permalink: https://www.hzdr.de/publications/Publ-33656
Publ.-Id: 33656


[18F]FLUDA automation

Lai, T. H.; Wenzel, B.; Moldovan, R.-P.; Brust, P.; Kopka, K.; Teodoro, R.

Bei diesem Datensatz handelt es sich um HPLC-Daten von den Radiosynthesen von [18F]FLUDA.

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Permalink: https://www.hzdr.de/publications/Publ-33655
Publ.-Id: 33655


Multivariate statistical modelling to improve particle treatment verification: Implications for prompt gamma-ray timing

Schellhammer, S.; Wiedkamp, J.; Löck, S.; Kögler, T.

We present an improved method for in-vivo proton range verification by prompt gamma-ray timing based on multivariate statistical modelling.

To this end, prompt gamma-ray timing distributions acquired during pencil beam irradiation of an acrylic glass phantom with air cavities of different thicknesses were analysed. Relevant histogram features were chosen using forward variable selection and the Least Absolute Shrinkage and Selection Operator (LASSO) from a feature assortment based on recommendations of the Image Biomarker Standardisation Initiative. Candidate models were defined by multivariate linear regression and evaluated based on their coefficient of determination \(R^2\) and root mean square error \(RMSE\).

The newly developed models showed a clearly improved predictive power (\(R^2 > 0.7\)) compared to the previously used models (\(R^2 < 0.5\)) and allowed for the identification of introduced air cavities in a scanned treatment field. %The parameter selection showed better predictive power of the energy-specific models (RM SE < 1,8 mm) compared to the energy-independent models (RM SE > 3 mm).
%for counting statistics equivalent to a single spot measured with eight detector units.

These results demonstrate that elaborate statistical models can enhance prompt gamma ray based treatment verification and increase its potential for routine clinical application.

Keywords: proton therapy; treatment verification; prompt gamma-ray timing; machine learning; multivariate modelling

Permalink: https://www.hzdr.de/publications/Publ-33654
Publ.-Id: 33654


Immobilization of radiotoxic elements with Y-stabilized zirconia: the Thorium case

Svitlyk, V.; Weiß, S.; Hennig, C.

Y-stabilized zirconia (YSZ) phases were found to incorporate Th atoms and the corresponding solubility ranges depend on the relative Y content. For the tetragonal phases with lower Y concentration of 14 at.% a maximal possible Th intake on the Zr/Y metal site reached ca. 10.3 at.%. Cubic phases with higher Y content could dissolve 11 at.% Th in equilibrium state and up to ca. 12.3 at.% Th under non-equilibrium conditions. Larger Th-Zr/Y solubility range for phases with higher Y concentration was found to be related to the associated symmetry increase, as concluded from synchrotron radiation powder diffraction data. Specifically, introduction of Th into tetragonal YSZ induces evolution towards higher cubic symmetry via flattening of the Zr/YO8 polyhedra. In addition, tetragonal YSZ crystal lattice exhibits strongly anisotropic expansion with concomitant decrease in tetragonality upon the intake of Th. This results in easier accommodation of bigger Th atoms via structural stabilization of longer Zr/Y-O bonding distances which yields more symmetrical coordination of central Zr/Y metal ions by surrounding O atoms. Cubic symmetry is, therefore, more favorable to incorporation of large tetravalent Actinide elements.

Keywords: nuclear waste; radioactive actinides; migration; zirconia ceramics; YSZ; structure; symmetry

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Permalink: https://www.hzdr.de/publications/Publ-33653
Publ.-Id: 33653


Sulfide-associated hydrothermal dolomite and calcite reveal a shallow burial depth of Alpine-type Pb-Zn deposits

Giorno, M.; Barale, L.; Bertok, C.; Frenzel, M.; Looser, N.; Guillong, M.; Bernasconi, S.; Martire, L.

Difficulties in dating Mississippi Valley-type (MVT) mineralization and the often closely-associated regional dolomitization events have led to considerable controversy regarding the typical tectonic contexts in which they form. This paper presents the first radiometric datings for the Gorno district in Lombardy, Italy, a classic example of the Alpine subclass of MVT deposits. U-Pb dating of hydrothermal carbonate minerals pre- and post-dating the main ore-forming event shows that both regional dolomitization and base-metal mineralization must have occurred within <10 Ma of the deposition of the Carnian host rocks. This implies that the ore deposits of the Gorno district, and probably other Alpine-type deposits, formed at shallow burial, prior to the western Tethys rifting phase. Concurrent Triassic magmatism and extensional tectonics likely contributed to the high geothermal heat fluxes necessary to drive the associated large-scale hydrothermal system. These findings contradict the general paradigm for MVT genesis, i.e., a preferred occurrence in deep-burial settings associated with compressional tectonics.

Keywords: MVT deposits; U-Pb dating of carbonate minerals

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  • Secondary publication expected

Permalink: https://www.hzdr.de/publications/Publ-33652
Publ.-Id: 33652


On the validation of ATHLET 3-D features for the simulation of multidimensional flows in horizontal geometries under single-phase subcooled conditions

Diaz Pescador, E.; Schäfer, F.; Kliem, S.

This paper provides an assessment of fluid transport and mixing processes inside the primary circuit of the test facility ROCOM through the numerical simulation of Test 2.1 with the system code ATHLET. The experiment represents an asymmetric injection of cold and non-borated water into the reactor coolant system (RCS) of a pressurized water reactor (PWR) to restore core cooling, an emergency procedure which may subsequently trigger a core re-criticality. The injection takes place at low velocity under single-phase subcooled conditions and presents a major challenge for the simulation in lumped parameter codes, due to multidimensional effects in horizontal piping and vessel arising from density gradients and gravity forces. Aiming at further validating ATHLET 3-D capabilities against horizontal geometries, the experiment conditions are applied to a ROCOM model, which includes a newly developed horizontal pipe object to enhance code prediction inside coolant loops. The obtained results show code strong simulation capabilities to represent multidimensional flows. Enhanced prediction is observed at the vessel inlet compared to traditional 1-D approach, whereas mixing overprediction from the descending denser plume is observed at the upper-half downcomer region, which leads to eventual deviations at the core inlet.

Keywords: ATHLET; 3-D features; coolant mixing; ROCOM Test 2.1; buoyancy-driven flow

Permalink: https://www.hzdr.de/publications/Publ-33651
Publ.-Id: 33651


Metal deportment in Pb-Zn mine wastes from a historic tailings pond, Plombières, East Belgium

Bevandic, S.; Blannin, R.; Gomez Escobar, A.; Bachmann, K.; Frenzel, M.; Pinto, A.; Relvas, J.; Muchez, P.

The exploitation of mine wastes materials as secondary resources requires in-depth mineralogical analyses, with metal deportment being of particular relevance for metal recovery. Using a combination of the Scanning Electron Microscope (SEM)-based Mineral Liberation Analyser (MLA) and Electron Probe Micro-Analyser (EPMA) methods, the deportment of Zn and Pb in the historic Plombières mine site (East Belgium) was investigated. The mine site comprises four different materials: soil, metallurgical waste, brown and yellow tailings. The integration of the MLA and EPMA data allowed the identification and quantification of Pb- and Zn-bearing phases, including minerals present in low abundances as well as slag phases. Slags and Pb oxide are the main source of Pb in different types of mine waste, followed by cerussite and/or anglesite. Zinc is mainly hosted by slags or by fraipontite, with minor amounts contributed by sphalerite, gahnite, willemite and bannisterite. Uncertainties on the metal deportments were estimated by bootstrap resampling and are typically low. The highest uncertainties are observed when the metal-bearing phases are present in low abundances, which is particularly noticeable in the yellow tailings. Mineral deportment studies should become a standard step in the process of maximising the potential of the mine waste deposits. The integrated approach of MLA-EPMA applied in this paper has proven to be effective for assessing the metal deportment between mineral and slag phases in mine wastes and could be successfully applied for other metals and waste deposits which originated from pyrometallurgical processing of the ore.

Keywords: Geometallurgy; Mine waste; Automated mineralogy; Nugget effect

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Permalink: https://www.hzdr.de/publications/Publ-33650
Publ.-Id: 33650


Preface to the Thematic Section: Mine tailings – Problem or opportunity? Towards a combined remediation and resource recovery approach

Machiels, L.; Frenzel, M.; Goldmann, D.; Illikainen, M.; Pfister, S.

Since the earliest days of the Industrial Revolution, Europe has been discarding vast quantities of mining residues, commonly referred to as “extractive waste.” Even today, 900 Mton/year of extractive waste is being generated and stored in tailing facilities or ponds. This 900 Mton/year fgure corresponds to 26% of the EU’s current waste output . Without proper management, tailing ponds can lead to environmental problems, ranging from acid mine drainage (AMD) and water contamination to dam bursts and fooding, air pollution, and soil erosion and contamination.

Keywords: No keywords

Permalink: https://www.hzdr.de/publications/Publ-33649
Publ.-Id: 33649


Timing of magmatic-hydrothermal activity in the Variscan Orogenic Belt – LA-ICP-MS U-Pb geochronology of skarn-related garnet from the Schwarzenberg District, Erzgebirge.

Reinhardt, N.; Gerdes, A.; Beranoaguirre, A.; Frenzel, M.; Meinert, L. D.; Gutzmer, J.; Burisch, M.

Here we present in-situ U-Pb laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) ages of andradite-grossular garnet from four magmatichydrothermal polymetallic skarn prospects in the Schwarzenberg District, Erzgebirge (Germany), located in the internal zone of the Variscan Orogenic Belt. Within the geochronological framework of igneous rocks and hydrothermal mineralization in the Erzgebirge, the obtained garnet ages define three distinct episodes of Variscan skarn formation: (I) early late-collisional mineralization (338-331 Ma) recording the onset of magmatic-hydrothermal fluid flow shortly after the peak metamorphic event, (II) latecollisional mineralization (~327-310 Ma) related to the emplacement of large peraluminous granites following large-scale extension caused by orogenic collapse and (III) post-collisional mineralization (~310-295 Ma) contemporaneous with widespread volcanism associated with Permian crustal reorganization. Our results demonstrate that the formation of skarns in the Schwarzenberg District occurred episodically in all sub-stages of the Variscan orogenic cycle over a time range of at least 40 Ma. This observation is consistent with the age range of available geochronological data related to magmatic-hydrothermal ore deposits from other internal zones of the Variscan Orogenic Belt in central and western Europe. In analogy to the time-space relationship of major porphyry-Cu belts in South America, the congruent magmatic-hydrothermal evolution in the internal zones and the distinctly later (by ~30 Ma) occurrence of magmatic-hydrothermal ore deposits in the external zones of the Variscan Orogenic Belt may be interpreted as a function of their tectonic position relative to the Variscan collisional front.

Keywords: U-Pb LA-ICP-MS garnet geochronology; Skarn; Tin-tungsten deposits; Magmatic-hydrothermal; Variscan orogeny; Erzgebirge

Permalink: https://www.hzdr.de/publications/Publ-33648
Publ.-Id: 33648


Ab initio path integral Monte Carlo approach to the momentum distribution of the uniform electron gas at finite temperature without fixed nodes

Böhme, M.; Dornheim, T.; Militzer, B.; Vorberger, J.

We present extensive new ab initio path integral Monte Carlo results for the momentum distribution function n(k) of the uniform electron gas in the warm dense matter regime over a broad range of densities and temperatures. This allows us to study the nontrivial exchange-correlation-induced increase of low-momentum states around the Fermi temperature, and to investigate its connection to the related lowering of the kinetic energy compared to the ideal Fermi gas. In addition, we investigate the impact of quantum statistics on both n(k) and the off-diagonal density matrix in coordinate space, and find that it cannot be neglected even in the strongly coupled electron liquid regime. Our results were derived without any nodal constraints, and thus constitute a benchmark for other methods and approximations.

Keywords: Statistical Physics; Path-Intergral Monte-Carlo; Warm Dense Matter; Uniform-electron-gas

  • Poster
    17th International Conference on the Physics of Non-Ideal Plasmas, 19.-24.09.2021, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33647
Publ.-Id: 33647


Nonlinear optical fullerene and graphene-based polymeric 1D photonic crystals: perspectives for slow and fast optical bistability

Kislyakov, I.; Ivanov, P.; Nunzi, J.-M.; Vlasov, A.; Ryzhov, A.; Venediktova, A.; Wang, H.; Wang, Z.; Zhang, T.; Dong, N.; Wang, J.

Nonlinear optical (NLO) properties of materials can be enhanced by assembling them as thin polymer composite films alternating with other polymers and forming dielectric mirrors, 1D photonic crystals (1DPCs), wherein the input light intensity is increased. Based on the poly(vinyl carbazole) (PVK) and poly(vinyl alcohol) (PVA) contrasting polymer pair, variants of such structures, with graphene and fullerene in their high-index layers, have been produced. Their optical switching characteristics have been studied with ns, cw, and quasi-cw fs laser sources in the IR and with a fs laser in the visible range. We have demonstrated slow optical bistability in the polymeric 1DPCs determined by the thermal expansion of polymer composites at intensities over 100W/cm² as well as fast and ultrafast optical switching due to thermo-optic and Kerr nonlinearities, respectively. A subpicosecond fast spectral shift of the 1DPC bandgap has been found. Our results and analysis provide a clear picture of the NLO behavior of 1DPCs at different time scales. The results stimulate the subsequent design of ultrafast switches and bistable memory cells based on polymeric 1DPCs whose micrometer thickness and flexibility offer promise for implementation into fiber and microchip configurations.

Keywords: Photonic crystals; Fullerene; Graphene; Nonlinear absorption

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Permalink: https://www.hzdr.de/publications/Publ-33646
Publ.-Id: 33646


Conventional versus Microwave-Assisted Roasting of Sulfidic Tailings: Mineralogical Transformation and Metal Leaching Behavior

Kamariah, N.; Kalebic, D.; Xanthopoulos, P.; Blannin, R.; Araujo, F.; Koelewijn, S.; Dehaen, W.; Binnemans, K.; Spooren, J.

Roasting is often required to convert sulfidic minerals into their sulfate and/or oxide
forms with the aim to increase the extractability of targeted metals. In this study, sulfidic
tailings of Neves Corvo Cu-Zn-Pb-mine (Portugal) underwent conventional roasting
(CR) and microwave-assisted roasting (MR) to compare the effect of both heating
technologies on the roasting behavior. Upon roasting in air, transformations of mineral
phases in the tailings were studied by different techniques using quantitative X-ray
diffraction, mineral liberation analysis, Raman spectroscopy and
thermogravimetry−differential scanning calorimetry coupled to mass spectrometry.
Also, the leaching behavior of elements from the roasted tailings was assessed in
water. It was shown that CR and MR induce different reaction pathways for mineral
transformations during roasting. While CR leads to indirect pyrite oxidation through
intermediate sulfate formation, direct pyrite oxidation to oxides is the main
transformation pathway during MR. This change in reaction pathway can be attributed
to the mineral-selective heating induced by microwaves, which in particular accelerates
the oxidation rate of pyrite. In agreement with the proposed roasting mechanism, the
leaching behavior in water showed that the CR tailings resulted in a higher extraction
of the studied metals (Cu, Zn, Pb, As and Fe) – since sulfate phases are more
abundant – compared to the MR tailings at the same roasting temperature. Overall, the
optimal leaching efficiency of the metals was reached after one hour roasting at
500−550 °C for both CR and MR

Keywords: Conventional roasting; Microwave roasting; Sulfidic tailings; Mineralogical transformation; Water

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Permalink: https://www.hzdr.de/publications/Publ-33645
Publ.-Id: 33645


Experiences with photocathode lasers for ELBE SRF Gun

Ryzhov, A.

A short report on experiences with UV photocathode lasers and laser beam line for ELBE SRF Gun in 2020-2021

Keywords: UV laser; SRF Gun; Accelerator; Photocathode laser

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  • Lecture (Conference)
    PITZ Collaboration Meeting, 23.-24.11.2021, Zeuthen, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-33644
Publ.-Id: 33644


Therapeutic Potential of Nitric Oxide releasing Selective Estrogen Receptor Modulators (NO-SERMs) in Malignant Melanoma

Bechmann, N.; Calsina, B.; Richter, S.; Pietzsch, J.

Malignant melanoma has a steadily increasing incidence, but treatment options are still limited and prognosis for patients, especially for men, is poor. To investigate whether targeting estrogen receptor (ER) signaling is a valid therapeutic approach, we retrospectively analyzed ER gene expression profiles in 448 melanoma patients. High ERα gene expression was associated with improved overall survival (HR=0.881; 95% Cl=0.793-0.979, p=0.018) and increased with tumor stage, while ERβ gene expression did not change with tumor progression. This seemingly protective function of ERα led us to speculate that specific targeting of ERβ has a therapeutic benefit in malignant melanoma. A new type of ERβ-selective ER modulator with a nitric oxide (NO•) releasing moiety (NO-SERM 4d) significantly reduced the pro-metastatic behavior of two melanoma cell lines (A2058 and MelJuso). Epithelial-mesenchymal transition in melanoma is consistent with a switch from E- to N-cadherin expression, mediating the invasive phenotype. NO-SERM 4d reduced N-cadherin expression and impaired spheroid formation in A2058 cells. In addition, growth of A2058 spheroids was significantly reduced, confirming the anti-tumorigenic potential of NO-SERM 4d. Targeting ERβ signaling combined with targeted NO• release represents a promising therapeutic approach in malignant melanoma that has potential to prevent metastatic spread and reduce tumor growth.

Keywords: bifunctional drugs; cadherins; epithelial-mesenchymal transition; nitric oxide donors; skin cancer; selective estrogen receptor modulators (SERMs); metastasis; tamoxifen; tumor spheroid model

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Permalink: https://www.hzdr.de/publications/Publ-33643
Publ.-Id: 33643


Pages: [1.] [2.] [3.] [4.] [5.] [6.] [7.] [8.] [9.] [10.] [11.] [12.] [13.] [14.] [15.] [16.] [17.] [18.] [19.] [20.] [21.] [22.] [23.] [24.] [25.] [26.] [27.] [28.] [29.] [30.] [31.] [32.] [33.] [34.] [35.] [36.] [37.] [38.] [39.] [40.] [41.] [42.] [43.] [44.] [45.] [46.] [47.] [48.] [49.] [50.] [51.] [52.] [53.] [54.] [55.] [56.] [57.] [58.] [59.] [60.] [61.] [62.] [63.] [64.] [65.] [66.] [67.] [68.] [69.] [70.] [71.] [72.] [73.] [74.] [75.] [76.] [77.] [78.] [79.] [80.] [81.] [82.] [83.] [84.] [85.] [86.] [87.] [88.] [89.] [90.] [91.] [92.] [93.] [94.] [95.] [96.] [97.] [98.] [99.] [100.] [101.] [102.] [103.] [104.] [105.] [106.] [107.] [108.] [109.] [110.] [111.] [112.] [113.] [114.] [115.] [116.] [117.] [118.] [119.] [120.] [121.] [122.] [123.] [124.] [125.] [126.] [127.] [128.] [129.] [130.] [131.] [132.] [133.] [134.] [135.] [136.] [137.] [138.] [139.] [140.] [141.] [142.] [143.] [144.] [145.] [146.] [147.] [148.] [149.] [150.] [151.] [152.] [153.] [154.] [155.] [156.] [157.] [158.] [159.] [160.] [161.] [162.] [163.] [164.] [165.] [166.] [167.] [168.] [169.] [170.] [171.] [172.] [173.] [174.] [175.] [176.] [177.] [178.] [179.] [180.] [181.] [182.] [183.] [184.] [185.] [186.] [187.] [188.] [189.] [190.] [191.] [192.] [193.] [194.] [195.] [196.] [197.] [198.] [199.] [200.] [201.] [202.] [203.] [204.] [205.] [206.] [207.] [208.] [209.] [210.] [211.] [212.] [213.] [214.] [215.] [216.] [217.] [218.] [219.] [220.] [221.] [222.] [223.] [224.] [225.] [226.] [227.] [228.] [229.] [230.] [231.] [232.] [233.] [234.] [235.] [236.] [237.] [238.] [239.] [240.] [241.] [242.] [243.] [244.] [245.] [246.] [247.] [248.] [249.] [250.] [251.] [252.] [253.] [254.] [255.] [256.] [257.] [258.] [259.] [260.] [261.] [262.] [263.] [264.] [265.] [266.] [267.] [268.] [269.] [270.] [271.] [272.] [273.] [274.] [275.] [276.] [277.] [278.] [279.] [280.] [281.] [282.] [283.] [284.] [285.] [286.] [287.] [288.] [289.] [290.] [291.] [292.] [293.] [294.] [295.] [296.] [297.] [298.] [299.] [300.] [301.] [302.] [303.] [304.] [305.] [306.] [307.] [308.] [309.] [310.] [311.] [312.] [313.] [314.] [315.] [316.] [317.] [318.] [319.] [320.] [321.] [322.] [323.] [324.] [325.] [326.] [327.] [328.] [329.] [330.] [331.] [332.] [333.] [334.] [335.] [336.] [337.] [338.] [339.] [340.] [341.] [342.] [343.] [344.] [345.] [346.] [347.] [348.] [349.]