Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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41396 Publications

DFT Insight into the Photocatalytic Properties of PtSSe-Se vdW Heterostructure

Sudheer, A. E.; Devaraj, M.; Posselt, M.

Inspired by the high photoconversion efficiency of 2D nanomaterials, we designed novel vdW heterostructure PtSSe-Se for the solar mediated photocatalytic hydrogen production. We investigated basic electrical and optical characteristics using ab-initio Density Functional Theory (DFT) calculations. Further, we performed electrostatic potential calculation to evaluate band alignments of PtSSe and Se, which revealed the water splitting capacity of the heterostructure. Later, the Gibbs free energy analysis also shows the heterostructure construction reduced the barrier height for the water reduction reaction effectively. Our in-depth investigation revealed the synergistic effect of built in electric field in the Janus PtSSe structure as well as generated electric field due to the heterostructure model have significant role in improving the photocatalytic efficiency. The dual electric field creation due to this unique structure effectively suppressed the charge carrier recombination and lead to enhanced lifetime of charge carriers in this PtSSe-Se heterostructure. In addition to that, the decreased lattice mismatch, elevated visible light response and fast charge transfer are the other factors that enhanced the photocatalytic efficiency of this Janus-chalcogenide heterostructure in a better way.

Keywords: 2D materials; van der Waals heterostructures; PtSSe-Se; DFT calculations

  • Poster
    Recent Progress in Graphene and 2D materials Research” (RPGR) 2023, Bengaluru, India, 20.-23.11.2023, Bengaluru, India

Permalink: https://www.hzdr.de/publications/Publ-38190
Publ.-Id: 38190


Graphene Oxide and Bacteria Interactions. What is Known and What Should We Expect?

Simeonova, D.; Pollmann, K.; Bianco, A.; Lièvremont, D.

Graphene-based nanomaterials have gained over the last two decades’ considerable attention due to their intrinsic physicochemical properties that are or can potentially be exploited. Besides, a lot of concern regarding the potential toxicity of graphene-based nanomaterials has emerged. One aspect of this concern is the interactions between graphene-based materials and different environmental compartments, especially indigenous microbial communities. As recent research showed that these graphene-based materials impacted bacterial pure culture or bacterial communities, these interactions have to be further studied to better understand and assess the fate of these materials in the environment.

Keywords: Biodegradation; graphene

Permalink: https://www.hzdr.de/publications/Publ-38189
Publ.-Id: 38189


Multiphase Experiments and CFD for Nuclear Reactor Safety Research

Lucas, D.

While according to the state of the art safety analyses related to nuclear reactor thermal hydraulics are done using system codes, CFD becomes more and more important as a tool to support such analyses. Often multiphase flows are involved in the flow situations that have to be considered. Since the Euler-Euler CFD modelling is not yet mature, experiments are necessary to improve and validate the CFD models.
This lecture will discuss typical topics of Nuclear Reactor Safety (NRS) research related to multiphase CFD. Several experiments done at the TOPFLOW facility of Helmholtz-Zentrum Dresden – Rossendorf (HZDR) to support the qualification of multiphase CFD for safety related issues will be presented. This includes information on the applied two-phase flow measuring techniques. The experiments range from rather generic experiments investigating vertical pipe flows at parameters relevant for safety analyses to experiments that represent specific safety related scenarios. Examples of the latter are counter-current flow limitation in a hot leg model and experiments on a model of a PWR cold leg and downcomer simulator. Finally, the applicability of Open Source codes for nuclear reactor safety research will be discussed and a German project to establish a validated CFD-tool based on OpenFOAM will be presented.

Keywords: CFD; multiphase; experiments; measuring techniques

  • Lecture (others)
    Advanced nuclear energy technology and nuclear safety, 14.-17.11.2023, Xi'an, China

Permalink: https://www.hzdr.de/publications/Publ-38188
Publ.-Id: 38188


Euler-Euler CFD Modelling for Multiphase Flows

Lucas, D.

Computational Fluid Dynamics (CFD) becomes more and more important for industrial process design and optimisation as well as analyses related to safety issues. While CFD is an established tool for single phase flows, e.g. in automotive or aviation industries, it is not yet mature for multiphase flows. The main reason is the complexity and multiscale nature of the interactions between the phases.
For medium and large industrial scales, as they are typical for nuclear reactor safety research, the multi-fluid or Euler-Euler approach is most frequently used and often the only feasible one. It allows for relative large sizes of the numerical cells, but has the price that all the unresolved phenomena have to be considered by closure models. The accuracy of these closure models is still limited because of a lack of knowledge and data for the small scale phenomena of multiphase flows.
The lecture will focus on gas-liquid flows and present strategies to 1) improve the reliability of Euler-Euler-CFD simulations and 2) extent the range of applicability of CFD by considering different morphologies of multiphase flows and allowing for transitions between these morphologies.

Keywords: CFD; multiphase; Euler-Euler

  • Lecture (others)
    Advanced nuclear energy technology and nuclear safety, 14.-17.11.2023, Xi'an, China

Permalink: https://www.hzdr.de/publications/Publ-38187
Publ.-Id: 38187


Novel Deep Learning Algorithms for Microscopy and Where to Find Them in Clinics

Yakimovich, A.

ML and DL are revolutionising our abilities to analyse biomedical images. Among other host-pathogen interactions may be readily deciphered from microscopy data using convolutional neural networks (CNN). We demonstrate in several studies how the definition of novel ML/DL tasks may aid in studying infection and disease phenotypes. Specifically, ML/DL algorithms may allow unambiguous scoring of virus-infected and uninfected cells in the absence of specific labelling. Accompanied by interpretability approaches, the ability of CNN to learn representations, without explicit feature engineering, may allow for uncovering yet unknown phenotypes in microscopy. Furthermore, we demonstrate novel ML/DL approaches to simplified 3D microscopy acquisition using conventional 2D hardware. Taken together, we show novel approaches to established algorithms in Computer Vision and Data Science. Applied to microscopy data, these approaches allow for the extraction of observations from datasets large enough to not be suitable for manual analysis. We argue that this shows that reformulating conventional ML/DL tasks to answer biological questions may facilitate novel discoveries in Infection and Disease Biology.

Keywords: clinical microscopy; deep learning

  • Invited lecture (Conferences)
    IUGA 48th Annual Meeting 2023, 21.-23.06.2023, Hague, Netherlands

Permalink: https://www.hzdr.de/publications/Publ-38186
Publ.-Id: 38186


Novel machine learning and data science tools to study infection phenotypes in cells

Yakimovich, A.

Advances in Machine Learning and Deep Learning are revolutionising our abilities to analyse biomedical images. These algorithms may allow unambiguous scoring of virus-infected and uninfected cells in the absence of specific labelling. Furthermore, accompanied by interpretability approaches, the ability of convolutional neural networks to learn representations, without explicit feature engineering, may allow for uncovering yet unknown phenotypes in microscopy. In our recent work, we employ the CapsNet architecture equipped with a discriminator and generator. This allowed us to differentiate between intracellular and extracellular Vaccinia virus particles through a classification task using the discriminator part of the architecture. Additionally, using the generator part we were able to visualise the differences between these particles. Finally, we show how a phenotype-centric open-source Python package we developed can facilitate the data science work on virological plaque assay. We designed the package to provide biologists with tools that make phenotypes as intuitive as data frames. We show that our phenotype-centric library can be employed for a range of pathogens like Vaccinia virus or Coronavirus, as well as variations of virological plaque assay including fluorescence-based or crystal violet staining-based assay images.

Keywords: deep learning; virology; high-content imaging; microscopy

  • Invited lecture (Conferences)
    COVID-19 Workshop: lessons learned from the pandemic, 05.-7.06.2023, Goerlitz, Germany

Permalink: https://www.hzdr.de/publications/Publ-38185
Publ.-Id: 38185


Precipitation Stripping of V(V) as a Novel Approach for the Preparation of Two-Dimensional Transition Metal Vanadates

Guadalupe Sánchez-Loredo, M.; Chekhonin, P.; Ebert, D.; Fischer, U.; Liu, X.; Möckel, R.; Judith Labrada-Delgado, G.; Passerini, S.; Kelly, N.

Cobalt, nickel, manganese and zinc vanadates were synthesized by a hydrometallurgical two-phases method. The extraction of vanadium(V) ions from alkaline solution using Aliquat®336
was followed by the production of metal vanadates through precipitation stripping. Precipitation stripping was carried out using solutions of the corresponding metal ions (Ni(II), Co(II), Mn(II) and Zn(II), 0.05 mol/L in 4 mol/L NaCl), and the addition time of the strip solution was varied (0, 1 and 2 h). The time-dependent experiments showed a notorius influence on the composition, structure, morphology and crystallinity of the two-dimensional vanadate products. Inspired by these findings, we selected two metallic vanadate products and studied their properties as alternative cathode materials for nonaqueous sodium and lithium metal batteries.

Keywords: two-dimensional materials; transition metal vanadates; solvent extraction; precipitation stripping; cathode materials; batteries

Permalink: https://www.hzdr.de/publications/Publ-38184
Publ.-Id: 38184


Colouring impurities removal and feldspar flotation using pneumatic ImhoflotTM H-Cell

Hoang, D. H.; Huber, S.; Imhof, R.; Rudolph, M.

The beneficiation of feldspar ore typically consists of desliming, magnetic separation, high solids conditioning, and flotation. Depending on the mineral composition, different flotation processes could be applied, i.e., double-reverse or reverse-direct flotation to remove the colouring impurities such as mica, Fe-bearing minerals, rutile, clay etc. and float feldspar from feldspar-quartz. Applications of 60 m3/h semi-industrial ImhoflotTM H-16 cell demonstrated its ability to achieve high feldspar grade and recovery in only one single cell which is compared to the existing bank mechanical cells. For oxide flotation, the underflow product contains 0.048 % Fe2O3 which is slightly higher than 0.043 % Fe2O3 using four industrial cells. The feldspar concentrate grade of one H-Cell is 93.7 % is similar to the existing flotation circuit, including rougher, scavenger and cleaner banks, even the feldspar feed grade fed to the pilot plant was only 38.7 % compared to 63.9 % in the industrial flotation circuit.

  • Poster
    Flotation '23 Conference, 06.-09.11.2023, Cape Town, South Africa

Permalink: https://www.hzdr.de/publications/Publ-38183
Publ.-Id: 38183


Novel application of pneumatic flotation cell for efficient graphite recovery from black mass: advancing critical raw material recycling

Vanderbruggen, A.; Salces, A. M.; José Rodríguez-Medina, A.; Rudolph, M.; Hoang, D. H.

Black mass, the fine fraction from spent Li-ion batteries, needs to be recycled both for its valuable metal oxides and spheroidized graphite particles. Still, current recycling techniques show less preference for graphite, despite being a critical raw material, due to lower economic incentives. Flotation is a suitable and cost-efficient process for graphite recovery before downstream processing, however its effective separation from the black mass is hindered by the (ultra)fine particles. To address this challenge, a pneumatic ImhoflotTM cell is employed in this study. The cell utilizes high-shear turbulence to generate fine bubbles, facilitating dispersion/de-agglomeration of particles and removal of adhered slimes, enhancing reagent selectivity, and reducing dosing requirements. ImhoflotTM cell offers advantages over mechanical and column flotation, including increased recovery of fine particles, rapid flotation kinetics, and high attachment rates and reducing the fine entrained metal oxides particles into the concentrate. This research presents a promising approach for efficient graphite recovery from spent Li-ion batteries, securing the sustainable recycling of critical raw materials.

  • Lecture (Conference)
    Flotation '23 Conference, 06.-09.11.2023, Cape Town, South Africa

Permalink: https://www.hzdr.de/publications/Publ-38182
Publ.-Id: 38182


Fused beads for the analysis of Li bearing samples by LIBS and XRF

Ebert, D.; Möckel, R.; Renno, A.; Schneider, A.; Dittrich, T.

In recent decades, it has become apparent that due to the increasing complexity of deposits, the complexity of ore samples is also increasing. At the same time, the need for detailed geological and mineralogical information also increased. Therefore, it is important to combine methods in order to obtain more comprehensive conclusions.
We present a method of combining WDXRF (wavelength dispersive X-ray fluorescence) analyses with a wide spectrum of elements and pLIBS (portable laser induced breakdown spectroscopy, see Fig. 1) with a likewise spectrum and the additional possibility to detect light elements such as Li. Nevertheless, the representativeness of LIBS analyses is significantly smaller compared to XRF. To overcome this and effectively combine both methods, we designed and produced fused beads using Na2B4O7 as flux. Unfortunately, such beads are transparent to the laser which makes LIBS analysis almost impossible, therefore, we tested two different approaches: 1) dying the bead by adding CuO to the flux and 2) roughen the beads surface. We used a mixture of Na2B4O7 (+ CuO) + KI as matrix. Potassium iodide (KI) was added as a releasing agent. We used Greisen rocks from the Altenberg-Zinnwald district with known composition – including Li – and LiBO2 in different concentration ratios to adjust the Li content.
To produce crack-free beads, we had to adapt the melting process in the fully automatic melting furnace TheOx (CLAISSE). For the analytical work, we use a portable LIBS instrument manufactured by SciAps (Z-300, laser wavelength 1064 nm) and a PANalytical Axiosmax minerals XRF spectrometer.
The fused beads will now serve as calibration samples for both XRF and LIBS measurements (see Fig. 2). Samples with unknown composition will be analysed by XRF first. It turned out that roughening the beads has no significant influence on the XRF-spectra as revealed in before and after scan measurements. In a second step the LIBS analysis is performed in particular for light element determination such as Li. Furthermore, adding a dying component such as Cu might be suitable as a robust internal standard for both LIBS and XRF.

The obvious disadvantage of the method is that neither Cu, K nor Na can be included in the quantitative analysis. Depending on the analytical problem, they would have to be determined in a preceding step (e.g. via a conventional Li-borate melt and XRF).

Keywords: LIBS; XRF; Lithium

  • Poster
    MinWien2023, 17.-21.09.2023, Wien, Österreich

Permalink: https://www.hzdr.de/publications/Publ-38181
Publ.-Id: 38181


Impact of hyperfine contributions on the ground state of spin-ice compounds

Gronemann, J.; Chattopadhyay, S.; Gottschall, T.; Osmic, E.; Islam, A. T. M. N.; Anand, V. K.; Lake, B.; Kaneko, H.; Suzuki, H.; Wosnitza, J.; Herrmannsdörfer, T.

We examined the magnetic ground state of the pyrochlore spin-ice compounds Pr2Hf2O7 and Ho2Ti2O7 by means of specific-heat, magnetization, and ac-susceptibility measurements in the mK regime. At these low temperatures, we observe an unexpected large specific heat and corresponding entropy, which diminish in applied magnetic fields. This evidences the presence of additional states beyond the electronic spin and orbital degrees of freedom. We can qualitatively explain the large specific heat by the coupling of the nuclear spins of 141Pr and 165Ho with their electronic counterparts, which leads to a complex hyperfine-coupled term scheme. With increasing fields, the nuclear and electronic spins decouple leaving only the electronic excitations in the measured temperature window. At intermediate fields, a rather evolved term scheme emerges that may explain the unusual hysteretic magnetization and a remarkable state with a negative magnetization found for Ho2Ti2O7. Our findings bring deep insights to the complex ground state of pyrochlore spin-ice compounds and their low-energy excitations.

Downloads

  • Secondary publication expected from 14.12.2024

Permalink: https://www.hzdr.de/publications/Publ-38175
Publ.-Id: 38175


Field-induced compensation of magnetic exchange as the possible origin of reentrant superconductivity in UTe2

Helm, T.; Kimata, M.; Sudo, K.; Miyata, A.; Stirnat, J.; Förster, T.; Hornung, J.; König, M.; Sheikin, I.; Pourret, A.; Lapertot, G.; Aoki, D.; Knebel, G.; Wosnitza, J.; Brison, J.-P.

The potential spin-triplet heavy-fermion superconductor UTe2 exhibits signatures of multiple distinct superconducting phases. For field aligned along the b axis, a metamagnetic transition occurs at μ0Hm ≈ 35 T. It is associated with magnetic fluctuations that may be beneficial for the field-reinforced superconductivity surviving up to Hm. Once the field is tilted away from the b towards the c axis, a reentrant superconducting phase emerges just above Hm. In order to better understand this remarkably field-resistant superconducting phase, we conducted magnetic-torque and magnetotransport measurements in pulsed magnetic fields. We determine the record-breaking upper critical field of μ0Hc2 ≈ 73T and its evolution with angle. Furthermore, the normal-state Hall effect experiences a drastic suppression indicative of a reduced band polarization above Hm in the angular range around 30° caused by a partial compensation between the applied field and an exchange field. This promotes the Jaccarino-Peter effect as a likely mechanism for the reentrant superconductivity above Hm.

Permalink: https://www.hzdr.de/publications/Publ-38174
Publ.-Id: 38174


Neutron radiography of an anisotropic drainage flow

Skrypnik, A.; Cole, K.; Lappan, T.; Brito-Parada, P. R.; Neethling, S. J.; Trtik, P.; Eckert, K.; Heitkam, S.

The data set includes original data for the paper "Neutron radiography of an anisotropic drainage flow".

Keywords: drainage; foam; neutron radiography; anisotropic draiange

Permalink: https://www.hzdr.de/publications/Publ-38173
Publ.-Id: 38173


alpaka-group/alpaka: alpaka 1.0.0: The One Release

Bastrakov, S.; Bastrakova, K.; Bocci, A.; Di Pilato, A.; Ehrig, S.; Ferragina, L.; Gruber, B. M.; Kaever, C.; Kelling, J.; Martin-Haugh, S.; Perego, A.; Stephan, J.; Widera, R.; Young, J.

The alpaka library is a header-only C++17 abstraction library for accelerator development. Its aim is to provide performance portability across accelerators through the abstraction (not hiding!) of the underlying levels of parallelism.

Keywords: CUDA; HPC; alpaka; OpenMP; HIP; C++; GPU; heterogeneous computing; performance portability; FPGA; SYCL

  • Software in external data repository
    Publication year 2023
    Programming language: C++
    System requirements: OS: Linux, Windows, or macOS Software requirements: C++17 compiler, Boost 1.74.0+, CMake 3.22+
    License: MPL-2.0 (Link to license text)
    Hosted on GitHub: Link to location
    DOI: 10.5281/zenodo.4452613

Permalink: https://www.hzdr.de/publications/Publ-38172
Publ.-Id: 38172


Prediction of radiation pneumonitis using the effective α/β of lungs and heart in NSCLC patients treated with proton beam therapy

Weiß, A.; Löck, S.; Xu, T.; Liao, Z.; Hoffmann, A. L.; Troost, E. G. C.

Purpose: Radiation pneumonitis (RP) remains a major complication in non-small cell lung cancer (NSCLC) pa-
tients undergoing radiochemotherapy (RCHT). Traditionally, the mean lung dose (MLD) and the volume of the
total lung receiving at least 20 Gy (V20Gy) are used to predict RP in patients treated with normo-fractionated
photon therapy.
However, other models, including the actual dose-distribution in the lungs using the effective α/β model or a
combination of radiation doses to the lungs and heart, have been proposed for predicting RP. Moreover, the
models established for photons may not hold for patients treated with passively-scattered proton therapy (PSPT).
Therefore, we here tested and validated novel predictive parameters for RP in NSCLC patient treated with PSPT.
Methods: Data on the occurrence of RP, structure files and dose-volume histogram parameters for lungs and heart
of 96 NSCLC patients, treated with PSPT and concurrent chemotherapy, was retrospectively retrieved from
prospective clinical studies of two international centers. Data was randomly split into a training set (64 patients)
and a validation set (32 patients). Statistical analyses were performed using binomial logistic regression.
Results: The biologically effective dose (BED) of the’lungs - GTV’ significantly predicted RP ≥ grade 2 in the
training-set using both a univariate model (p = 0.019, AUCtrain = 0.72) and a multivariate model in combination
with the effective α/β parameter of the heart (pBED = 0.006, pα/βeff = 0.043, AUCtrain = 0.74). However, these
results did not hold in the validation-set (AUCval = 0.52 andAUCval = 0.50, respectively). Moreover, these models
were found to neither outperform a model built with the MLD (p = 0.015, AUCtrain = 0.73, AUCval = 0.51), nor a
multivariate model additionally including the V20Gy of the heart (pMLD = 0.039, pV20Gy,heart = 0.58, AUCtrain =
0.74, AUCval = 0.53).
Conclusion: Using the effective α/β parameter of the lungs and heart we achieved similar performance to
commonly used models built for photon therapy, such as MLD, in predicting RP ≥ grade 2. Therefore, prediction
models developed for photon RCHT still hold for patients treated with PSPT.

Keywords: NTCP; NSCLC; PSPT; Radiation pneumonitis; Effective α/β

Permalink: https://www.hzdr.de/publications/Publ-38169
Publ.-Id: 38169


A Phase I Study of the DNA-PK Inhibitor Peposertib in Combination with Radiotherapy with or without Cisplatin in Patients with Advanced Head and Neck Tumors

Samuels, M.; Falkenius, J.; Bar-Ad, V.; Dunst, J.; van Triest, B.; Yachnin, J.; Rodriguez-Gutierrez, A.; Kuipers, M.; You, X.; Sarholz, B.; Locatelli, G.; Becker, A.; Troost, E. G. C.

Purpose: DNA-dependent protein kinase (DNA-PK) plays a key role in the repair of DNA double strand breaks via nonho-
mologous end joining. Inhibition of DNA-PK can enhance the effect of DNA double strand break inducing anticancer thera-
pies. Peposertib (formerly “M3814”) is an orally administered, potent, and selective small molecule DNA-PK inhibitor that has
demonstrated radiosensitizing and antitumor activity in xenograft models and was well-tolerated in monotherapy. This phase
1 trial (National Clinical Trial 02516813) investigated the maximum tolerated dose, recommended phase 2 dose (RP2D),
safety, and tolerability of peposertib in combination with palliative radiation therapy (RT) in patients with thoracic or head
and neck tumors (arm A) and of peposertib in combination with cisplatin and curative-intent RT in patients with squamous
cell carcinoma of the head and neck (arm B).
Methods and Materials: Patients received peposertib once daily in ascending dose cohorts as a tablet or capsule in combina-
tion with palliative RT (arm A) or in combination with intensity modulated curative-intent RT and cisplatin (arm B).
Results: The most frequently observed treatment-emergent adverse events were radiation skin injury, fatigue, and nausea in
arm A (n = 34) and stomatitis, nausea, radiation skin injury, and dysgeusia in arm B (n = 11). Based on evaluations of dose-
limiting toxicities, tolerability, and pharmacokinetic data, RP2D for arm A was declared as 200 mg peposertib tablet once daily
in combination with RT. In arm B (n = 11), 50 mg peposertib was declared tolerable in combination with curative-intent RT
and cisplatin. However, enrollment was discontinued because of insufficient exposure at that dose, and the RP2D was not for-
mally declared.
Conclusions: Peposertib in combination with palliative RT was well-tolerated up to doses of 200 mg once daily as tablet with each
RT fraction. When combined with RT and cisplatin, a tolerable peposertib dose yielded insufficient exposure. Ó 2023 The Authors.
Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Permalink: https://www.hzdr.de/publications/Publ-38168
Publ.-Id: 38168


Patients’ needs in Proton Therapy: a survey among 10 European Facilities

Mazzola, G. C.; Bergamaschi, L.; Vincini, M.; Pepa, M.; Zaffaroni, M.; Volpe, S.; Rombi, B.; Doyen, J.; Fossati, P.; Haustermans, K.; Hoyer, M.; Langendijk, H.; Matute, R.; Orlandi, E.; Rylander, H.; Troost, E. G. C.; Orecchia, R.; Alterio, D.; Jereczek-Fossa, B.

Aims: The number of Proton Therapy (PT) facilities is still limited worldwide, and the access to treatment could
be characterized by patients’ logistic and economic challenges. Aim of the present survey is to assess the support
provided to patients undergoing PT across Europe.
Methods: Through a personnel contact, an online questionnaire (62 multiple-choice and open-ended questions)
via Microsoft Forms was administered to 10 European PT centers. The questionnaire consisted of 62 questions
divided into 6 sections: i) personal data; ii) general information on clinical activity; iii) fractionation, concurrent
systemic treatments and technical aspects of PT facility; iv) indication to PT and reimbursement policies; v)
economic and/ or logistic support to patients vi) participants agreement on statements related to the possible
limitation of access to PT. A qualitative analysis was performed and reported.
Results: From March to May 2022 all ten involved centers filled the survey. Nine centers treat from 100 to 500
patients per year. Paediatric patients accounted for 10–30%, 30–50% and 50–70% of the entire cohort for 7, 2
and 1 center, respectively. The most frequent tumours treated in adult population were brain tumours, sarcomas
and head and neck carcinomas; in all centers, the mean duration of PT is longer than 3 weeks. In 80% of cases,
the treatment reimbursement for PT is supplied by the respective country’s Health National System (HNS). HNS
also provides economic support to patients in 70% of centers, while logistic and meal support is provided in 20%
and 40% of centers, respectively. PT facilities offer economic and/or logistic support in 90% of the cases. Logistic
support for parents of pediatric patients is provided by HNS only in one-third of centers. Overall, 70% of re-
spondents agree that geographic challenges could limit a patient’s access to proton facilities and 60% believe that
additional support should be given to patients referred for PT care.

Keywords: Proton therapy Facilities; Europe; Survey; Support strategies; Patients

Permalink: https://www.hzdr.de/publications/Publ-38167
Publ.-Id: 38167


Lung cancer multi-omics digital human avatars for integrating precision medicine into clinical practice: the LANTERN study

Lococo, F.; Boldrini, L.; Diepriye, C.-D.; Evangelista, J.; Nero, C.; Flamini, S.; Minucci, A.; de Paolis, E.; Vita, E.; Cesario, A.; Annunziata, S.; Calcagni, M.; Chiappetta, M.; Cancellieri, A.; Larici, A.; Cicchetti, G.; Troost, E. G. C.; Róza, Á.; Farré, N.; Öztürk, E.; van Doorne, D.; Leoncini, F.; Urbani, A.; Trisolini, R.; Bria, E.; Giordano, A.; Rindi, G.; Sala, E.; Tortora, G.; Valentini, V.; Boccia, S.; Margaritora, S.; Scambia, G.

Background The current management of lung cancer patients has reached a high level of complexity. Indeed, besides the traditional clinical variables (e.g., age, sex, TNM stage), new omics data have recently been introduced in clinical practice, thereby making more complex the decision-making process. With the advent of Artificial intelligence (AI) techniques, various omics datasets may be used to create more accurate predictive models paving the way for a
better care in lung cancer patients.
Methods The LANTERN study is a multi-center observational clinical trial involving a multidisciplinary consortium of five institutions from different European countries. The aim of this trial is to develop accurate several predictive models for lung cancer patients, through the creation of Digital Human Avatars (DHA), defined as digital representations of patients using various omics-based variables and integrating well-established clinical factors with genomic data, quantitative imaging data etc. A total of 600 lung cancer patients will be prospectively enrolled by the recruiting centers and multi-omics data will be collected. Data will then be modelled and parameterized in an experimental context of cutting-edge big data analysis. All data variables will be recorded according to a shared common ontology based on variable-specific domains in order to enhance their direct actionability. An exploratory
analysis will then initiate the biomarker identification process. The second phase of the project will focus on creating multiple multivariate models trained though advanced machine learning (ML) and AI techniques for the specific areas of interest. Finally, the developed models will be validated in order to test their robustness, transferability and generalizability, leading to the development of the DHA. All the potential clinical and scientific stakeholders will
be involved in the DHA development process. The main goals aim of LANTERN project are: i) To develop predictive models for lung cancer diagnosis and histological characterization; (ii) to set up personalized predictive models for individual-specific treatments; iii) to enable feedback data loops for preventive healthcare strategies and quality of life management.
Discussion The LANTERN project will develop a predictive platform based on integration of multi-omics data. This will enhance the generation of important and valuable information assets, in order to identify new biomarkers that can be used for early detection, improved tumor diagnosis and personalization of treatment protocols.
Ethics Committee approval number 5420 − 0002485/23 from Fondazione Policlinico Universitario Agostino Gemelli IRCCS – Università Cattolica del Sacro Cuore Ethics Committee.
Trial registration clinicaltrial.gov - NCT05802771.

Keywords: Lung cancer; Artificial intelligence (AI); Digital human avatars (DHA); Personalize medicine; Machine learning; system medicine; precision medicine; genomics; radiomics; big data

Permalink: https://www.hzdr.de/publications/Publ-38166
Publ.-Id: 38166


Normo-or hypo-fractionated photon or proton radiotherapy in the management of locally advanced unresectable pancreatic cancer: a systematic review

Elkhamisy, S. A.; Valentini, C.; Lattermann, A.; Radhakrishna, G.; Künzel, L. A.; Löck, S.; Troost, E. G. C.

LAPC is associated with a poor prognosis and requires a multimodal treatment approach. However, the role of radiation therapy in LAPC treatment remains controversial. This systematic review aimed to explore the role of proton and photon therapy, with varying radiation techniques and fractionation, in treatment outcomes and their respective toxicity profiles. Methods: Clinical studies published from 2012 to 2022 were systematically reviewed using PubMed, MEDLINE (via PubMed) and Cochrane databases. Different radiotherapy-related data were extracted and analyzed. Results: A total of 31 studies matched the inclusion criteria. Acute toxicity was less remarkable in stereotactic body radiotherapy (SBRT) compared to conventionally fractionated radiotherapy (CFRT), while in proton beam therapy (PBT) grade 3 or higher acute toxicity was observed more commonly with doses of 67.5 Gy (RBE) or higher. Late toxicity was not reported in most studies; therefore, comparison between groups was not possible. The range of median overall survival (OS) for the CFRT and SBRT groups was 9.3–22.9 months and 8.5–20 months, respectively. For the PBT group, the range of median OS was 18.4–22.3 months. Conclusion: CFRT and SBRT showed comparable survival outcomes with a more favorable acute toxicity profile for SBRT. PBT is a promising new treatment modality; however, additional clinical studies are needed to support its efficacy and safety.

Keywords: locally advanced pancreatic adenocarcinoma; photon therapy; SBRT; proton beam therapy; systematic review

Permalink: https://www.hzdr.de/publications/Publ-38164
Publ.-Id: 38164


CFD simulation of flashing scenarios for nuclear safety analysis: possibilities and challenges

Liao, Y.

Due to its relevance for the safety analysis of pressurized water reactors, many research activities on flashing flows in pipes and nozzles arose from the mid of last century. Most of them have focused on the mass flow rate and pressure or temperature fluctuation by means of experiments and system codes. Owing to the increase in computer speed and progress in numerical algorithm, CFD is used more and more in the investigation of flashing flows, which has the advantage of providing further insights regarding the internal flow structure as well as its evolution. Various mixture or two-fluid models have been proposed in the literature. However, knowledge on local non-equilibrium effects, interphase transfer as well as interfacial area under different flashing conditions is still insufficient; a general and precise definition of the problem remains a challenge. In this lecture, two-fluid modelling of various nuclear flashing scenarios such as pipe blowdown, nozzle flow, steam-generator leakage, flashing-induced instability and pressure release will be presented. The performance of different mass transfer models including thermal phase-change, pressure phase-change, relaxation and equilibrium models will be compared. Challenges related to interfacial heat transfer, bubble poly-dispersity as well as flow regime transition will be discussed.

Keywords: Computational Fluid Dynamics; Flashing flows; Nuclear safety analysis; Challenges

  • Lecture (others)
    Advanced nuclear energy technology and nuclear safety, 14.-17.11.2023, Xi'an, China

Permalink: https://www.hzdr.de/publications/Publ-38163
Publ.-Id: 38163


Wearable Magnetic Field Sensor with Low Detection Limit and Wide Operation Range for Electronic Skin Applications

Li, S.; Wu, Y.; Asghar, W.; Li, F.; Zhang, Y.; He, Z.; Liu, J.; Wang, Y.; Liao, M.; Shang, J.; Ren, L.; Du, Y.; Makarov, D.; Liu, Y.; Li, R.-W.

Flexible electronic devices extended abilities of humans to perceive their environment conveniently and comfortably. Among them, flexible magnetic field sensors are crucial to detect changes in the external magnetic field. State-of-the-art flexible magnetoelectronics do not exhibit low detection limit and large working range simultaneously, which limits their application potential. Herein, a flexible magnetic field sensor possessing a low detection limit of 22 nT and wide sensing range from 22 nT up to 400 mT is reported. With the detection range of seven orders of magnitude in magnetic field sensor constitutes at least one order of magnitude improvement over current flexible magnetic field sensor technologies. The sensor is designed as a cantilever beam structure accommodating a flexible permanent magnetic composite and an amorphous magnetic wire enabling sensitivity to low magnetic fields. To detect high fields, the anisotropy of the giant magnetoimpedance effect of amorphous magnetic wires to the magnetic field direction is explored. Benefiting from mechanical flexibility of sensor and its broad detection range, its application potential for smart wearables targeting geomagnetic navigation, touchless interactivity, rehabilitation appliances, and safety interfaces providing warnings of exposure to high magnetic fields are explored.

Keywords: flexible magnetic field sensors

Permalink: https://www.hzdr.de/publications/Publ-38157
Publ.-Id: 38157


Curvilinear and 3D magnetism: current research and technology perspectives

Makarov, D.

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

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

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

Related publications

  • Invited lecture (Conferences)
    VIII Conference of the Italian Association of Magnetism (AIMAGN) - Magnet-2024, 07.-09.02.2024, Milano, Italy

Permalink: https://www.hzdr.de/publications/Publ-38156
Publ.-Id: 38156


Dimensional crossover and reentrant superconductivity in pressurized kagome metals AV3Sb5

Uykur, E.; Wenzel, M.; Faria, M.; Mavridou, K.; Luferau, A.; Ortiz, B. R.; Wilson, S.; Tsirlin, A. A.

Non-magnetic kagome metals, AV₃Sb₅ (A: K, Rb, Cs), offer a new promising platform for engineering topological and correlated electrons [1,2]. At ambient pressure, these compounds show a competition between an exotic charge-density wave and superconductivity that are rooted in an intricate interplay of topologically non-trivial Dirac fermions, localized flat-band electrons, and van Hove singularities in the vicinity of the Fermi level. These features can be traced back to the effectively 2D band structure of vanadium kagome planes. We pioneered the broadband optical studies of AV₃Sb₅ and identified a significant damping of charge carriers [3, 4, 5], potentially related to electron-phonon coupling that has immediate implications for superconductivity.

The tunability of these properties with external means opens interesting new directions in the research of kagome metals. For example, an unusual reentrant superconductivity of AV₃Sb₅ was observed in transport measurements under pressure. In this presentation, I will summarize pressure evolution of AV₃Sb₅ revealed by single-crystal XRD, high-pressure infrared spectroscopy, and density-functional calculations. This combination of experimental and computational techniques allows a simultaneous probe of crystal and electronic structures under both hydrostatic and non-hydrostatic conditions. We show that, despite the initial similarity of AV₃Sb₅ with different alkaline metals (A = K, Rb, Cs) at ambient pressure, these compounds show a different sequence of pressure-induced structural phase transitions, which further depend on the extent of non-hydrostaticity of the pressure environment [6, 7].

Electronic structure calculated using experimental atomic positions and also probed directly by infrared spectroscopy reveals a dimensional crossover caused by the formation of interlayer Sb-Sb bonds [7]. The strongly 2D structures of AV₃Sb₅ become essentially 3D at elevated pressures. These changes lead to a reconstruction of the Fermi surface that clearly correlates with the reentrant behavior of superconductivity. We further reveal the interplay between topological and localized carriers that follow the evolution of the Fermi surface.

Our study demonstrates pressure-induced dimensional crossover as an important tool for tailoring novel electronic materials, such as kagome metals. Concurrently, we show that their high-pressure phases intimately depend on the pressure environment and its deviation from hydrostaticity.

[1] B. R. Ortiz et al., Phys. Rev. Materials 3, 094407 (2019)
[2] H. Luo et al., Nature Communications 13, 273 (2022)
[3] E. Uykur et al., Phys. Rev. B 104, 045130 (2021)
[4] E. Uykur et al., npj Quantum Materials 7, 16 (2022)
[5] M. Wenzel et al. Phys. Rev. B 105, 245123 (2022)
[6] A. A. Tsirlin et al. SciPost Physics 12, 049 (2022)
[7] A. A. Tsirlin et al. arXiv: 2209.02794

  • Lecture (Conference)
    The Joint 28th AIRAPT and 60th EHPRG International Conference on High Pressure Science and Technology, 23.-28.07.2023, Edinburgh, UK

Permalink: https://www.hzdr.de/publications/Publ-38155
Publ.-Id: 38155


Optical studies of magnetic kagome metals: Effect of magnetism, localized carriers and phonons

Uykur, E.

Kagome metals attract a lot of attention as materials that combine two extreme features in their electronic structure: Massless Dirac fermions with linear band dispersion and flat bands hosting massive localized electrons. Topological nature of the former and strongly correlated nature of the latter lead to multitude of exotic phenomena, including quantum anomalous Hall effect and novel states, such as axion insulators. The electron dynamics of these systems is the key for understanding the proposed exotic phenomena including topological properties, strong electron correlations, and magnetism; along with the interplay of those.

To this end, we have employed optical spectroscopy on a series of kagome metals with different magnetic ground states. Interband and intraband transitions have been traced with broadband IR spectroscopy, where the signatures of itinerant and localized carriers have been identified. The relaxation dynamics of different contributions have also been investigated via ultrafast optical pump-probe spectroscopy. Moreover, the effect of underlying magnetic structure on the observed features and the behavior of the phonons have been discussed. In this talk, I summarize the optical fingerprints of unconventional features in magnetic kagome metals.

  • Invited lecture (Conferences)
    Low-Energy Electrodynamics in Solids 2023, 25.-30.06.2023, Sankt Pölten, Austria

Permalink: https://www.hzdr.de/publications/Publ-38154
Publ.-Id: 38154


Broadband optical investigations of the CDW state in kagome metals AV3Sb5 (A = K, Rb, Cs)

Uykur, E.; Wenzel, M.; Ortiz, B. R.; Wilson, S. D.; Winnerl, S.; Dressel, M.; Tsirlin, A. A.

We present a broadband optical study of non-magnetic kagome metals AV3Sb5 (A = K, Rb, Cs) down to 10 K. Different contributions to the optical spectra have been discussed and compared with the DFT calculations in normal and charge density wave (CDW) states. Spectra reflect the response of the 2D Dirac fermions and are frequency-independent in a broad energy range. Low energies are governed by the itinerant and localized charge carriers that show a spectral weight redistribution below the CDW transition. Our results show that the CDW gaps evolve systematically between the siblings (K

  • Lecture (Conference)
    DPG-Frühjahrstagung der Sektion Kondensierte Materie (SKM), 26.-31.03.2023, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38153
Publ.-Id: 38153


Optimisation of synthesis procedures and structural investigation of monazite-cheralite solid solutions

Lender, T.; Braga Ferreira Dos Santos, L.; Gericke, R.; Huittinen, N. M.; Peters, L.

The monazite-cheralite solid solutions LnPO4-Ca0.5Th0.5PO4 with Ln = La, Gd were prepared via a co-precipitation route, showcasing an optimised, scalable synthesis procedure for a possible waste form accommodating high level liquid waste streams. A distortion of the cheralite structure with respect to the monazite structure was observed throughout both solid solutions as evidenced by a deviation of the lattice parameters from the linear behaviour known from other monazite solid solutions. Using a high temperature flux method, cheralite single crystals were grown for the first time for in-depth structural investigations. Both thorium and calcium were found to deviate from the central position of the LnO9 polyhedron, supporting previous neutron diffraction investigations of identical cheralite samples.

Keywords: X-ray diffraction; solid solution; cheralite; lanthanides; actinides; single crystal flux growth

Permalink: https://www.hzdr.de/publications/Publ-38152
Publ.-Id: 38152


Thermal sensing interface for bioassay monitoring in well plates

Nieder, D.; Janićijević, Ž.; Baraban, L.

Poster on a single-element thermal sensor in a 3D printed well format for the monitoring of biological assays. The modified Transient Plane Source sensing technique is used for simultaneous measurement of the thermal effusivity of various samples and as a heating element.

Keywords: Thermal sensor; Well plate; Biosensor

  • Poster
    HZDR DocSeminar 2023, 17.-19.10.2023, Schilbach, Germany

Permalink: https://www.hzdr.de/publications/Publ-38151
Publ.-Id: 38151


Fermiology of Strongly Correlated Metals

Wosnitza, J.

ein Abstract hat nicht vorgelegen

  • Invited lecture (Conferences)
    Workshop on "Electron Correlations: From Basic Properties to Applications, 30.11.2023, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38150
Publ.-Id: 38150


Eulerian simulation of a bubble column up to high gas fractions

Draw, M.; Rzehak, R.

This study investigates homogeneous flow in a bubble column up to a 50% gas holdup. For low to medium gas holdup the good performance of an established baseline model is confirmed. In this range, the mixture pressure gradient is decisive in determining the relative velocity, resulting in good predictions without considering the swarm effect. However, beyond a gas holdup of ~20%, a swarm corrector becomes necessary, for which several proposals from the literature are evaluated. In addition, the lift force influences the gas fraction profile depending on the bubble size. The resulting profile shape has a significant impact on the liquid flow inside the column. If the profile is wall-peaked, the liquid flow remains moderate, while a center-peaked profile strongly boosts the liquid velocity.

Keywords: dispersed gas-liquid flow; homogeneous bubble-column flow; Euler-Euler two-fluid model; swarm effect; lift force; CFD simulation

  • Lecture (Conference)
    The 11th International Flotation Conference (Flotation '23), 05.-09.11.2023, Kapstadt, Südafrika

Permalink: https://www.hzdr.de/publications/Publ-38148
Publ.-Id: 38148


Perfusion and Time of Exchange Measurements Using BBB-ASL in Gliomas: The Initial Experience

Turhan, G.; Çetin, A. İ.; Mahroo, A.; Padrela, B.; Konstandin, S.; Hoinkiss, D. C.; Breutigam, N. J.; Eickel, K.; Petr, J.; Mutsaerts, H.; Danyeli, A. E.; Ozduman, K.; Guenther, M.; Dincer, A.; Ozturk-Isik, E.

Subtle changes in BBB integrity might be missed by contrast-enhanced T1-weighted MRI. Blood-brain barrier arterial spin labeling (BBB-ASL) is a new technique to assess BBB disruptions. In this work, we measured the cerebral blood flow (CBF) and exchange time (Tex) values of the tumor, normal-appearing white matter, and normal-appearing gray matter regions in gliomas using BBB-ASL technique. Our results indicated higher CBF and leakier BBB in contrast-enhanced regions of gliomas than in the normal-appearing GM.

  • Contribution to proceedings
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada
    ISMRM '23: Proceedings of the ISMRM 31th Annual Meeting & Exhibition, 1757
  • Poster
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada

Permalink: https://www.hzdr.de/publications/Publ-38147
Publ.-Id: 38147


DEveloping Blood-Brain barrier arterial spin labeling as a non-Invasive Early biomarker (DEBBIE)

Padrela, B.; Tee, M.; Sneve, M.; Mahroo, A.; Geier, O.; Thomas, D.; Morgan, C.; Moyaert, P.; Ozturk, E.; Nordhøy, W.; Pålhaugen, L.; Linn, J.; Selnes, P.; Eickel, K.; Konstandin, S.; Kuijer, J.; Hoinkiss, D.; Breutigam, N.; Buck, M.; Achten, R.; Barkhof, F.; Hilal, S.; Fladby, T.; Anazodo, U.; Petr, J.; Mutsaerts, H. J. M. M.; Günther, M.

One of the earliest signs of Alzheimer’s disease (AD) is the loss of blood-brain barrier (BBB) integrity. Arterial spin labeling (ASL) MRI is a non-invasive way to measure perfusion and several other hemodynamic and physiological parameters, including vascular permeability. The DEveloping BBB-ASL as non-Invasive Early biomarker (DEBBIE) consortium aims to develop and integrate innovative techniques to allow robust BBB permeability assessments by ASL to develop a sensitive, non-invasive, and early biomarker for AD and related dementias. This work summarizes our planned efforts to develop and establish an MRI-based BBB permeability biomarker.

  • Contribution to proceedings
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada
    ISMRM '23: Proceedings of the ISMRM 31th Annual Meeting & Exhibition, 0367
  • Lecture (Conference)
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada

Permalink: https://www.hzdr.de/publications/Publ-38146
Publ.-Id: 38146


Blood-brain barrier permeability changes over the lifespan

Padrela, B.; Sneve, M. H.; Zelhorst, S.; Tee, M.; Mahroo, A.; Kuijer, J.; Walhovd, K.; Konstandin, S.; Eickel, K.; Barkhof, F.; Hilal, S.; Günther, M.; Mutsaerts, H. J. M. M.; Petr, J.

Blood-brain-barrier (BBB) dysfunction is a hallmark of aging-related disorders, including cerebral small vessel disease and Alzheimer’s disease. An emerging biomarker of BBB dysfunction is time of exchange (Tex) of water across the BBB as measured by multi-echo arterial spin labeling MRI. We evaluated Tex across the age spectrum in 40 adults from two cohorts of healthy controls, and demonstrated that Tex is higher in gray than in white matter, higher in females than in males, and that Tex decreases with age. These findings suggest that BBB permeability changes over the lifespan can be investigated using arterial spin labeling approaches.

  • Contribution to proceedings
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada
    ISMRM '23: Proceedings of the ISMRM 31th Annual Meeting & Exhibition, 1919
  • Poster
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada

Permalink: https://www.hzdr.de/publications/Publ-38145
Publ.-Id: 38145


ASL spatial coefficient of variance predicts increased white matter hyperintensities volume over time in cognitively unimpaired subjects

Padrela, B.; Collij, L. E.; Lorenzini, L.; Ingala, S.; Sudre, C.; Visser, P. J.; Den Braber, A.; Barkhof, F.; Petr, J.; Mutsaerts, H. J. M. M.

Arterial transit artifacts (ATAs) in arterial spin labeling (ASL) images are common in populations with prolonged arterial transit time (ATT) and may be associated with vascular insufficiency. The spatial coefficient of variance (sCoV) of ASL images can quantify the presence of these artifacts. Vascular insufficiency could contribute to the development of white matter hyperintensities (WMH), a common marker of cerebral small vessel disease. We demonstrated that baseline sCoV of CBF is associated with WMH at baseline and predicts WMH volume change, in a cognitively unimpaired population of 88 subjects.

  • Contribution to proceedings
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada
    ISMRM '23: Proceedings of the ISMRM 31th Annual Meeting & Exhibition, 0580
  • Poster
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada

Permalink: https://www.hzdr.de/publications/Publ-38144
Publ.-Id: 38144


Classification of IDH mutation with Arterial Spin Labeling and Dynamic Susceptibility Contrast MRI in adult gliomas

Prysiazhniuk, Y.; Server, A.; Bech-Aase, Ø.; Helseth, E.; Kala, D.; Eijgelaar, R. S.; Fuster-García, E.; Brandal, P.; Bjørnerud, A.; Otáhal, J.; Petr, J.; Nordhøy, W.

IDH genotype status is an important marker in glioma diagnostics. Given that IDH mutation affects the tumor vascularization pattern, perfusion imaging has the potential to become a non-invasive tumor histopathology assessor. In this study, two methods of perfusion MRI – Dynamic Susceptibility Contrast (DSC) and Arterial Spin Labeling (ASL) – were compared in their ability to assess IDH mutation status. DSC- and ASL-derived perfusion maps correlated significantly and were feasible parameters in the IDH classification task. Mean tumor CBF quantified with ASL had the highest AUC score, sensitivity, and specificity, supporting the feasibility of using ASL in clinical glioma diagnostics.

  • Contribution to proceedings
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada
    ISMRM '23: Proceedings of the ISMRM 31th Annual Meeting & Exhibition, 1747
  • Poster
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada

Permalink: https://www.hzdr.de/publications/Publ-38143
Publ.-Id: 38143


Cardiovascular and cerebrovascular health in 70-year-olds: a population-based ASL study

Dijsselhof, M. B. J.; James, S.-N.; Lorenzini, L.; Collij, L.; Thomas, D. L.; Scott, C.; Manning, E.; Józsa, T. I.; Cash, D.; Study, I.; Sudre, C.; Hughes, A. D.; Richards, M.; Barkhof, F.; Schott, J.; Petr, J.; Mutsaerts, H. J. M. M.

While mid-life cardiovascular pathology may lead to late-life cognitive decline, our understanding of the role of cerebrovascular health as an intermediate biomarker is limited. We explored the association between cardiovascular health biomarkers and cross-sectional and longitudinal cerebrovascular health assessed by ASL MRI in Insight46, a well-characterised cognitively normal population-based sample.

We found several cross-sectional and longitudinal associations between blood pressure and CBF. These findings suggest that the effects of BP on cerebrovascular health can be imaged with ASL perfusion MRI, possibly offering opportunities to prevent or intervene before cognitive decline sets in.

  • Contribution to proceedings
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada
    ISMRM '23: Proceedings of the ISMRM 31th Annual Meeting & Exhibition, 1304
  • Lecture (Conference)
    2023 ISMRM & ISMRT Annual Meeting & Exhibition, 03.06.2023, Toronto, Canada
  • Contribution to proceedings
    OHBM '23: Proceedings of the Organization for Human Brain Mapping Annual Meeting, 22.07.2023, Montreal, Canada
  • Poster
    OHBM '23: Proceedings of the Organization for Human Brain Mapping Annual Meeting, 22.07.2023, Montreal, Canada

Permalink: https://www.hzdr.de/publications/Publ-38142
Publ.-Id: 38142


Accelerator Mass Spectrometry of Actinides – Radiochemical Separations and Capabilities

Fichter, S.; Wallner, A.

Accelerator Mass Spectrometry (AMS) is an ultra-trace analytical technique capable of measuring radionuclides down to ppq levels (i. e. fg/g) and even below. Thus, AMS is especially competitive to classical radioanalytical techniques, such as α, or γ-spectrometry, for nuclides with half-lives > 10 years.
Amongst these radionuclides, actinides are easy-to-measure AMS nuclides as most of them lack isobaric nuclides with similar long half-lives. Hence, the measurement of actinides using AMS possesses a broad range of applications including nuclear safeguards and forensics, environmental studies, astrophysics and nuclear cross sections measurements to name just a few.
The new 1-MV AMS facility HAMSTER (Helmholtz Accelerator Mass Spectrometer Tracing Environmental Radionuclides) at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Germany, will be especially dedicated to the ana-lysis of actinides in ultra-trace levels. In addition to a multi-cathode cesium sputter ion source a state-of-the-art laser ion cooler setup will be installed at HAMSTER to access a broader range of radionuclides by enhanced isobar suppression.
The HAMSTER facility is also equipped with two new chemistry labs with capabilities for chemical sample workup for a broad range of radionuclides, especially actinides. These labs are operating under quasi-clean room conditions and are equipped with dedicated fume hoods for working with hydrofluoric acid and flow benches to minimize sample contamination on the ultra-trace level. Different radiochemical separation schemes for actinides (i.e. U, Pu) and other radionuclides are in routine operation whilst the separation of other actinides (Pa, Np, Am/Cm) is currently under development. In this talk different radiochemical work-up procedures will be presented and the future capabilities of the HAMSTER facility are highlighted

Related publications

  • Invited lecture (Conferences)
    SANDA Workshop, 06.12.2023, Geel, Belgien

Permalink: https://www.hzdr.de/publications/Publ-38138
Publ.-Id: 38138


Backreaction of cosmological perturbations

Zhuk, O.

We investigate the backreaction of nonlinear perturbations on the global evolution of the Universe within the cosmic screening approach. To this end, we have considered the second-order scalar perturbations. An analytical study of these perturbations followed by a numerical evaluation shows that, first, the corresponding average values have a negligible backreaction effect on the Friedmann equations and, second, the second-order correction to the gravitational potential is much less than the first-order quantity. Consequently, the expansion of perturbations into orders of smallness in the cosmic screening approach is correct. [https://doi.org/10.1016/j.physletb.2023.137797]

  • Open Access Logo Lecture (Conference)
    Progress on Old and New Themes in cosmology (PONT 2023), 02.-05.05.2023, Avignon, France

Downloads

Permalink: https://www.hzdr.de/publications/Publ-38137
Publ.-Id: 38137


N-body simulation of the cosmic screening effect

Zhuk, O.

We consider the large-scale structure formation within the cosmic screening approach. The main feature of this approach is that a careful analysis of the perturbed Einstein equations leads to the conclusion that there is an exponential cutoff of the gravitational interaction on large (of the order of 2–3 Gpc) cosmological scales. This is a purely relativistic effect associated with the non-linearity of Einstein's equations. Consequently, the gravitational potential is described by an equation of Helmholtz-type and not of Poisson-type and it has the form of the Yukawa potential, and not the Newton potential familiar to us from school days. To confirm this effect numerically, we perform the N-body simulation in a box with a comoving size of 5.632 Gps/h employing the relativistic code “gevolution” modified to our approach. We calculate the power spectra of the mass density contrast and find that these spectra cease to depend on time for scales beyond the cosmic screening length. This is a clear manifestation of the cosmic screening effect.

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    XXIII Gamow International Astronomical Conference “ASTRONOMY AND BEYOND: ASTROPHYSICS, COSMOLOGY AND GRAVITATION, ASTROPARTICLE PHYSICS, RADIOASTRONOMY, ASTROBIOLOGY AND GENETICS”, 21.-25.08.2023, Odessa, Ukraine

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Permalink: https://www.hzdr.de/publications/Publ-38136
Publ.-Id: 38136


EPICS Support for LB115 radiation datalogger

Meyer, M.

EPICS Support module to communicate with a LB115 stationary radiation datalogger from Berthold Technologies using the EPICS asyn support module for text-based communication over ethernet.

Keywords: EPICS; LB115

  • Software in external data repository
    Publication year 2023
    Programming language: C++
    System requirements: None
    License: MIT (Link to license text)
    Hosted on https://codebase.helmholtz.cloud/fwf-public/lb115-ioc: Link to location

Permalink: https://www.hzdr.de/publications/Publ-38135
Publ.-Id: 38135


Investigation on flow morphology and heat transfer for high-pressure steam condensation in an inclined tube at low inlet steam qualities

Boden, S.; Hampel, U.; Pietruske, H.; Bieberle, A.

We report on an experimental study of high-pressure (up to 65 bar) steam condensation heat transfer in a slightly inclined tube at the thermal-hydraulic test facility COSMEA. The study is part of an extended experimental program on this topic and focussed this time on heat transfer and two-phase flow at low inlet steam qualities (down to 2.8%). We determined condensation rates respectively total heat transfer, wall heat flux distribution and flow morphology using X-ray imaging and local temperature measurements.

Keywords: Condensation heat transfer; Heat exchangers; Two-phase flow; Heat flux; X-ray tomography; Passive safety systems

Related publications

Permalink: https://www.hzdr.de/publications/Publ-38134
Publ.-Id: 38134


Attraction Versus Repulsion Between Doublons or Holons in Mott-Hubbard Systems

Schützhold, R.; Queißer, F.; Schaller, G.

For the Mott insulator state of the Fermi-Hubbard model in the strong-coupling limit, we study the interaction between quasi-particles in the form of doublons and holons. Comparing different methods – the hierarchy of correlations, strong-coupling perturbation theory, and exact analytic solutions for the Hubbard tetramer – we find an effective interaction between doublons and/or holons to linear order in the hopping strength which can display attractive as well as repulsive contributions, depending on the involved momenta. Finally, we speculate about the implications of our findings for high-temperature uperconductivity.

Keywords: Hubbard model; Quasi-particles; Boltzmann equations; Superconductivity

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Permalink: https://www.hzdr.de/publications/Publ-38133
Publ.-Id: 38133


Physics and Chemistry of 2D Materials: Simulations

Kuc, A. B.

Two-dimensional (2D) materials have gained a lot of attention in the past decade, because of their extraordinary properties, often complementary to their bulk forms. The most striking example is graphene with Dirac cones, massless Dirac fermions, and topological and superconducting properties in the bilayer form with magic twist angles. Beside graphene, to date, there is a large variety of 2D materials, including inorganic transition-metal dichalcogenides (TMDC), organic 2D polymers, or mixed 2D perovskites, to mention just a few. In our group, we study these materials and their physical and chemical properties from first-principles simulations. In this talk, I will outline some of the group’s activities, especially in collaborations with experimental partners. The selected topics will cover optoelectronic properties TMDC heterostructures with 2D perovskite, single-metal catalysts inside graphene-like host, and sensing properties of SnP3.

  • Lecture (others)
    Chemistry Faculty Seminar at Wroclaw University, 04.04.2023, Wrocław, Polska

Permalink: https://www.hzdr.de/publications/Publ-38132
Publ.-Id: 38132


Energy transfer between gravitational waves and quantum matter

Schützhold, R.; Adamietz, F.; Gräfe, J.

We study the interaction between gravitational waves and quantum matter such as Bose-Einstein condensates, superfluid helium, or ultracold solids, explicitly taking into account the changes of the trapping potential induced by the gravitational wave. As a possible observable, we consider the change of energy due to the gravitational wave, for which we derive rigorous bounds in terms of kinetic energy and particle number. Finally, we discuss implications for possible experimental tests.

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Permalink: https://www.hzdr.de/publications/Publ-38131
Publ.-Id: 38131


Simulation of Raman Spectra

Kuc, A. B.

Summer school lecture on Raman spectra simulations within SPP 2244 project.

  • Lecture (others)
    SPP 2244 summer school, 31.08.2023, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-38130
Publ.-Id: 38130


Impact of tracer particles on the electrolytic growth of hydrogen bubbles

Han, Y.; Bashkatov, A.; Huang, M.; Eckert, K.; Mutschke, G.

The thermocapillary effect at gas bubbles growing at micro-electrodes seems well understood. However, the interfacial flow measured in the upper bubble part decays faster than found in first simulations by Massing et al. [“Thermocapillary convection during hydrogen evolution at microelectrodes,” Electrochim. Acta 297, 929 (2019)]. Recently, Meulenbroek et al. attributed the origin of the difference to the influence of surfactants being present in the electrolyte [“Competing Marangoni effects from a stagnant cap on the interface of a hydrogen bubble attached to a microelectrode,” Electrochim. Acta 385, 138298 (2021)]. Surprisingly, the presence of tracer particles added to the electrolyte for measuring its flow was not yet considered. Our recent experiments reveal that varying the small amount of tracer particles added influences the bubble shape, its dynamics and also the electrolyte flow nearby.
We therefore present a model to describe the particle attraction to and the particle dynamics at the bubble interface, which allows to quantify the impact. Corresponding simulations are validated against measurements for different bulk particle concentrations and show good agreement of the tangential velocity profile at the bubble interface caused by thermo- and solutocapillary effects. Depending on the particle concentration, parts of the upper bubble interface are found to become stagnant. The results allow a deeper insight into the complex phenomena of electrolytic gas evolution and further put attention to a careful application of particle-based measurement techniques in gas-liquid systems.

Keywords: gas evolution; electrolysis; capillary effects; PIV and PTV; tracer particles; numerical simulation

Permalink: https://www.hzdr.de/publications/Publ-38128
Publ.-Id: 38128


Development of Specific & High Affinity Polymer-binding Peptides for Microplastic Identification and for Enhanced Enzymatic Degradation

Harter, S. D.; Lederer, F.

Microplastic pollution is one of the most pressing problems of our time. There are innumerable sources of microplastic including the production of fine particulates as a by-product of various industrial processes. These particles mainly end up in landfills where they are released into the environment. Efficient recycling of these materials reduces microplastic pollution and saves primary resources for polymer production. However, economically and ecologically relevant recycling technologies for fine polymer particles are not yet established.
The aim of the presented work is to provide methods for rapid and simple analysis of complex environmental samples and the optimization of particle degradation. These methods will be based on low-cost and environmentally friendly peptides that bind specifically and with high affinity to polyethylene terephthalate (PET), polyamide and polyurethane, respectively.
To identify the peptides, phage surface display (PSD) is performed on micrometer-sized polymer particles. Eight putative PET binding phages were already identified by PSD using PET particles as target material. In future, isothermal titration calorimetry will be used to determine the thermodynamic parameters of the peptide-polymer interaction. To identify the chemical groups involved in binding, fourier-transformed infrared spectroscopy along with alanine scanning mutagenesis will be utilized. Upon optimization, the developed polymer-binding peptides will be heterologously expressed with different fluorescent labels. Flow cytometry will be used for the analysis and sorting of fluorescently marked particles. Cooperation partners at the Helmholtz Center Berlin will produce hybrids of the developed polymer-binding peptides and polymer-degrading enzymes to enhance enzyme-particle affinities resulting in improved polymer degradation.

Keywords: Microplastic; Polyethylene terephthtalat; Phage surface display; Polymer degradation; Polymer-binding peptides

  • Lecture (Conference)
    4th International Conference on Advanced Polymer Science and Engineering, 23.-25.10.2023, Valencia, Spanien

Permalink: https://www.hzdr.de/publications/Publ-38127
Publ.-Id: 38127


In-plane charged antiphase boundary and 180° domain wall in a ferroelectric film

Cai, X.; Chen, C.; Xie, L.; Wang, C.; Gui, Z.; Gao, Y.; Kentsch, U.; Zhou, G.; Gao, X.; Chen, Y.; Zhou, S.; Gao, W.; Liu, J.-M.; Zhu, Y.; Chen, D.

The deterministic creation and modification of domain walls in ferroelectric films have attracted broad interest due to their unprecedented potential as the active element in non-volatile memory, logic computation and energy-harvesting technologies. However, the correlation between charged and antiphase states, and their hybridization into a single domain wall still remain elusive. Here we demonstrate the facile fabrication of antiphase boundaries in BiFeO3 thin films using a He-ion implantation process. Cross-sectional electron microscopy, spectroscopy and piezoresponse force measurement reveal the creation of a continuous in-plane charged antiphase boundaries around the implanted depth and a variety of atomic bonding configurations at the antiphase interface, showing the atomically sharp 180° polarization reversal across the boundary. Therefore, this work not only inspires a domain-wall fabrication strategy using He-ion implantation, which is compatible with the wafer-scale patterning, but also provides atomic-scale structural insights for its future utilization in domain-wall nanoelectronics.

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Permalink: https://www.hzdr.de/publications/Publ-38126
Publ.-Id: 38126


Back-reaction and correlation effects on pre-thermalization in Mott-Hubbard systems

Queißer, F.; Kohlfürst, C.; Schützhold, R.

For the Fermi-Hubbard model in the strongly interacting Mott insulator state, we study the pre-thermalization dynamics after a quench. To this end, we employ the method of the hierarchy of correlations and compare different levels of accuracy. To leading order, the usual free quasi-particle dynamics (as encoded in the two-point correlation functions) yields the standard picture of pre-thermalization. Taking into account the back-reaction of these quasi-particle fluctuations onto the mean-field background as the first next-to-leading order effect, we observe a strong degradation of pre-thermalization, especially in low dimensions. In contrast, the inclusion of three-point correlations enhances pre-thermalization.

Keywords: Fermi-Hubbard model; Mott insulator

Permalink: https://www.hzdr.de/publications/Publ-38125
Publ.-Id: 38125


Dynamically Assisted Tunneling in the Floquet Picture

Ryndyk, D.; Kohlfürst, C.; Queißer, F.; Schützhold, R.

We study how tunneling through a potential barrier V(x) can be enhanced by an additional harmonically oscillating electric field E(t)=E0 cos(ωt). To this end, we transform into the Kramers-Henneberger frame and calculate the coupled Floquet channels numerically. We find distinct signatures of resonances when the incident energy E equals the driving frequency ω=E which clearly shows the breakdown of the time-averaged potential approximation. As a simple model for experimental applications (e.g., in solid state physics), we study the rectangular potential, which can also be benchmarked with respect to analytical results. Finally, we consider the truncated Coulomb potential relevant for nuclear fusion.

Keywords: Dynamically Assisted Quantum Tunneling; Assisted Hydrogen Fusion; High-Intensity Electric Fields; Coupled-Channel Equations

Permalink: https://www.hzdr.de/publications/Publ-38124
Publ.-Id: 38124


Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

Accardi, A.; Achenbach, P.; Adhikari, D.; et al; Ding, M.; Schmidt, S. M.

This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena.

Permalink: https://www.hzdr.de/publications/Publ-38123
Publ.-Id: 38123


A precession-driven flow in a cylindrical geometry

Giesecke, A.; Wilbert, M.; Grauer, R.; Simkanin, J.; Pizzi, F.; Kumar, V.; Anders, S.; Gundrum, T.; Stefani, F.

A magnetohydrodynamic dynamo process is supposed to take place in the
interior of the Sun or stars as well as in planets and smaller
celestial bodies like the ancient moon or the asteroid Vesta. The
ubiquity and diversity of astrophysical dynamo action, and the
importance of the magnetic fields for formation and evolution of the
objects generating them, has motivated related studies in the
laboratory. A new dynamo experiment is currently under construction
at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), in which a fluid flow
of liquid sodium will be forced by a precessing cylindrical container.
In the 1970s, a similar but much smaller experiment was conducted by
R. Gans, who found a threefold amplification of an external magnetic
field, indicating that dynamo action can be expected in the vicinity
of the transition from a laminar flow state to vigorous turbulence if
the system is sufficiently large. In the new dynamo precession
experiment the knowledge of the velocity field is necessary in order
to achieve the optimal structure of the flow and to understand the
interaction of fluid flow and magnetic field and the associated
transfer of kinetic energy into magnetic energy.

Our present study focuses on the experimental and numerical estimation
of the structure of a precession driven flow field, its scaling with
rotation and precession, and its dynamical evolution. We determine the
amplitude of characteristic flow contributions in terms of inertial
modes, which allows a robust and accurate detection of the transition
between laminar and turbulent state. It further turns out that most of
the kinetic energy can be related to very few large scale inertial
modes. Finally, the determination of the orientation of the rotation
axis of the fluid motion shows that the qualitative behavior of the
precession driven flow in a cylinder is roughly similar to the
predictions given by Busse's theory for a planetary-like setup in a
spheroid.

Keywords: Dynamo

  • Lecture (Conference)
    Geophysical Astrophysical Fluid Dynamics: Experiments and Models, 11.-15.09.2023, Nice, France

Permalink: https://www.hzdr.de/publications/Publ-38122
Publ.-Id: 38122


Improving Beam-Based Regulation for Continuous-Wave Linear Accelerators with a Disturbance Model-Based Design

Maalberg, A.

The present thesis is devoted to improving the temporal resolution of time-resolved accelerator-based experiments. Due to the fact that this temporal resolution is largely determined by the accelerator stability, specifically by the stability of the underlying electron beam, this work concentrates on the analysis, design and implementation of regulation algorithms in order to enhance the temporal stability of the electron beam. In this context, Chapter 2 investigates the problem of exploiting radio frequency noise for the purpose of modeling an electron beam disturbance. The investigation shows that a disturbance model that is based on the radio frequency noise may become
unnecessarily high-order, and even so, does not fully reflect the actual electron beam noise measured on the accelerator. Following this, Chapter 3 describes the design of a beam-based regulator that features a disturbance model that is derived from the measured electron beam noise data. The designed regulator is successfully evaluated on the continuous-wave linear accelerator ELBE. The presented results demonstrate that a single regulation stage, which is installed in a continuous-wave linear accelerator and features a disturbance model-based beam-based regulator, has a potential to outperform a commonly used proportional regulator, without compromising the plant stability. Finally, Chapter 4 presents a real-time feasible implementation of a high-order beam-based regulator that is ready to be employed for fast beam-based feedback.

Keywords: linear accelerators; continuous-wave mode; optimal control; field-programmable gate arrays

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  • Doctoral thesis
    Tallinn University of Technology, 2023

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Permalink: https://www.hzdr.de/publications/Publ-38121
Publ.-Id: 38121


Pressure evolution of electron dynamics in the superconducting kagome metal CsV₃Sb₅

Wenzel, M.; Tsirlin, A. A.; Capitani, F.; Chan, Y. T.; Ortiz, B. R.; Wilson, S. D.; Dressel, M.; Uykur, E.

  1. Data from the publication are given in Origin format with Figure codes.
  2. More data are available upon request.

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Permalink: https://www.hzdr.de/publications/Publ-38120
Publ.-Id: 38120


Estimation of Physical and Electrical Properties of Various REBCO Tapes for Construction of Very High Field REBCO Magnet

Song, J.-S.; Chaud, X.; Debray, F.; Paillot, K.; Fazilleau, P.; Lécrevisse, T.; Herrmannsdörfer, T.; Senatore, C.; Dhallé, M.; Smara, A.

The physical and electrical properties of four recent REBCO CC were assessed: 1) THEVA; 2) Shanghai Supercond. Technology; 3) Faraday Factory Japan; and 4) Fujikura. For estimating their physical properties, the delamination strength of each tape was checked by removing a polyimide ribbon sticked on the tape and by cutting the tape after pre-tinning. Their windability and the uniformity of their thickness were also investigated through our metal-as-insulation winding process. For evaluating their electrical properties, their critical current was measured at 4.2 K under various external magnetic fields perpendicular to their ab-plane. Joint samples of each tape were fabricated and tested in a bath of liquid nitrogen at 77 K in self-field. The results are described in this paper for the four tapes.

Permalink: https://www.hzdr.de/publications/Publ-38118
Publ.-Id: 38118


Magneto-optical response of the Weyl semimetal NbAs: Experimental results and hyperbolic-band computations

Polatkan, S.; Uykur, E.; Wyzula, J.; Orlita, M.; Shekhar, C.; Felser, C.; Dressel, M.; Pronin, A. V.

The magneto-optical properties of (001)-oriented NbAs single crystals have been studied in the spectral range
from 5 to 150 meV and in magnetic fields of up to 13 T. A rich spectrum of inter-Landau-level transitions is
revealed by these measurements. The transitions follow a square-root-like dependence with magnetic field, but
the simple linear-band approximation is unable to accurately reproduce the observed behavior of the transitions
in applied fields. We argue that the detected magneto-optical spectra should be related to crossing hyperbolic
bands, which form the W1 cones. We propose a model Hamiltonian, which describes coupled hyperbolic bands
and reproduces the shape of the relevant bands in NbAs. The magneto-optical spectra computed from this
Hamiltonian nicely reproduce our observations. We conclude that the hyperbolic-band approach is a minimal
model to adequately describe the magneto-optical response of NbAs and that the chiral (conical) bands do not
explicitly manifest themselves in the spectra.

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Permalink: https://www.hzdr.de/publications/Publ-38117
Publ.-Id: 38117


R&D of Photocathodes used for ELBE SRF Gun II

Schaber, J.

Presentation of the current research of Cs2Te photocathodes, ongoing surface studies of magnesium photocathodes for future higher quantum efficiency, and surface studies on p-GaN for future photocathode projects. The impact of surface cleaning on quantum efficiency was presented in this work.

Keywords: Cs2Te photocathode; magnesium photocathode; p-GaN photocathode; surface studies; semicondctor photocathodes

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  • Open Access Logo Invited lecture (Conferences)
    AccelencE Workshop 2023, 09.-11.10.2023, Leimen, Deutschland

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Permalink: https://www.hzdr.de/publications/Publ-38116
Publ.-Id: 38116


In depth Surface Studies on Mg Photocathodes for higher Quantum Efficiency

Schaber, J.

Metal cathodes are commonly used in
RF Guns because they work robustly and tolerate a poor vacuum. The main prerequisite for a high QE is surface cleanness (atomically clean surface). At ELBE, a successfully established process to clean Mg surfaces is laser cleaning, although this laser cleaning improves the QE, it causes a non uniform surface and potential surface damage. Generally, an alternative process producing an atomically clean, smooth, and damage-free surface is
desired.

Keywords: Magnesium photocathode; metal photocathode; quantum efficiency

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  • Open Access Logo Poster
    Photocathode Physics for Photoinjectors Workshop, 03.-05.10.2023, Stoney Brook University, USA

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Permalink: https://www.hzdr.de/publications/Publ-38115
Publ.-Id: 38115


Pion and kaon electromagnetic and gravitational form factors

Xu, Y.-Z.; Ding, M.; Raya, K.; Roberts, C. D.; Rodríguez-Quintero, J.; Schmidt, S. M.

A unified set of predictions for pion and kaon elastic electromagnetic and gravitational form factors is obtained using a symmetry-preserving truncation of each relevant quantum field equation. A key part of the study is a description of salient aspects of the dressed graviton + quark vertices. The calculations reveal that each meson’s mass radius is smaller than its charge radius, matching available empirical inferences; and meson core pressures are commensurate with those in neutron stars. The analysis described herein paves the way for a direct calculation of nucleon gravitational form factors.

Permalink: https://www.hzdr.de/publications/Publ-38114
Publ.-Id: 38114


Sieving parton distribution function moments via the moment problem

Wang, X.; Ding, M.; Chang, L.

We apply a classical mathematical problem, the moment problem, with its related mathematical achievements, to the study of the parton distribution function (PDF) in hadron physics, and propose a strategy to sieve the moments of the PDF by exploiting its properties such as continuity, unimodality, and symmetry. Through an error-inclusive sifting process, we refine three sets of PDF moments from Lattice QCD. This refinement significantly reduces the errors, particularly for higher order moments, and locates the peak of PDF simultaneously. As our strategy is universally applicable to PDF moments from any method, we strongly advocate its integration into all PDF moment calculations.

Permalink: https://www.hzdr.de/publications/Publ-38113
Publ.-Id: 38113


Surface studies of p-GaN:Cs photocathodes with in-situ X-ray photoelectron spectroscopy (XPS)

Schaber, J.

Higher beam currents and brightness are desired, therefore new photocathodes with higher QE are required.
p-type GaN can produce a negative electron affinity (NEA) surface when cesium is deposited on it.
A thermal cleaning under vacuum was carried out to achieve an atomically clean surface before the Cs deposition.

Keywords: p-GaN photocathode; XPS surface studies; semiconductor; surface cleaning

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  • Open Access Logo Poster
    Photocathode Physics for Photoinjectors Workshop, 03.-05.10.2023, Stoney Brook University, USA

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Permalink: https://www.hzdr.de/publications/Publ-38112
Publ.-Id: 38112


Constraining the pion distribution amplitude using Drell-Yan reactions on a proton

Xing, H.-Y.; Ding, M.; Cui, Z.-F.; Pimikov, A. V.; Roberts, C. D.; Schmidt, S. M.

Using a reaction model that incorporates pion bound state effects and continuum results for proton parton distributions and the pion distribution amplitude, $\varphi_\pi$, we deliver parameter-free predictions for the $\mu^+$ angular distributions in $\pi N \to \mu^+ \mu^- X$ reactions on both unpolarised and polarised targets. The analysis indicates that such angular distributions are sensitive to the pointwise form of $\varphi_\pi$ and suggests that unpolarised targets are practically more favourable. The precision of extant data is insufficient for use in charting $\varphi_\pi$; hence, practical tests of this approach to charting $\varphi_\pi$ must await data with improved precision from new-generation experiments. The reaction model yields a nonzero single-spin azimuthal asymmetry, without reference to $T$-odd parton distribution functions (DFs). This may necessitate additional care when attempting to extract such $T$-odd DFs from data.

Permalink: https://www.hzdr.de/publications/Publ-38111
Publ.-Id: 38111


Fundamentals of Scientific Metadata - Why context matters - HIDA Summer Accademie

Gerlich, S.; Trösch, M.; Schaller, T.

In this lesson we will look at the intricate relationship between (digital) research data, metadata and knowledge, discuss why metadata is critical in today’s research, as well as explain some of the technologies and concepts related to structured machine-readable metadata.

Have you ever struggled to make sense of scientific data provided by a collaborator - or even understanding your own data 5 months after publication? Do you see difficulties in meeting the data description requirements of your funding agency? Do you want your data to have lasting value, but don’t know how to ensure that?

Precise and structured description of research data is key for scientific exchange and progress - and also for the recognition of your effort in data collection. The solution: make your data findable, accessible, interoperable and reusable by describing them with metadata.

This course is targeted at scientific staff and researchers from all fields who are interested in annotating their research data with well-structured and useful metadata.

Keywords: Metadata Training; Fundamentals Training; HMC

  • Lecture (others) (Online presentation)
    HIDA Summer Accademie, 18.-29.09.2023, online, Germany

Permalink: https://www.hzdr.de/publications/Publ-38108
Publ.-Id: 38108


Data publication: In-depth Surface Studies of p-GaN:Cs Photocathodes by Combining Ex-Situ Analytical Methods with In-Situ X-Ray Photoelectron Spectroscopy

Schaber, J.

All datasets that were generated during the PhD period and evaluated for the PhD thesis. The data contains .txt files, fotos (.jpeg, .png, .tiff, etc.), SEM and AFM images of p-GaN, p-GaAs and Cs2Te semiconductor sample sets. The files are sorted by sample names and the sample files contain different datasets of each sample. The whole uploaded file contains original data of XPS and heating experiments as well as evaluated data of the original files. Experiments were done to study the surface cleanness by different solvents, thermal cleaning experiments in vacuum, cesium deposition, measurement of quantum efficiencies, and the lifetime of photocathodes. The Cs2Te experiments contain the deposition parameters of the cesium and tellurium deposition on copper and the preparation steps of the Cu substrate.

Keywords: GaN photocathode; III-V photocathode; surface cleaning; Cs deposition; high quantum efficiency; surface studies

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Permalink: https://www.hzdr.de/publications/Publ-38107
Publ.-Id: 38107


CCT2 - Training and Outreach

Gerlich, S.; Heel, L.; Langenbach, C.; Lemster, C.; Özkan, Ö.; Pörsch, A.; Schaller, T.; Trösch, M.

Training and Outreach are important tasks of HMC. The CCT2 Training and Outreach takes care of that.

Keywords: Helmholtz Metadata Collaboration; Training and Outreach; HMC Retreat

  • Poster
    HMC Retreat, 20.-22.11.2023, Göttingen, Germany

Permalink: https://www.hzdr.de/publications/Publ-38106
Publ.-Id: 38106


Field induced phase transition and magnetic phase diagram of multiferroic Ca2CoSi2O7

Pham, T. C.; van Vuong, H.; Anh Nguyen, T.; Dinh Bui, T.; Nam Hoang, N.

Magnetic phase transitions are important for the application of individual materials toward modern spintronics and sensing. Using high-resolution sound velocity and pyrocurrent measurements, we have obtained a detailed magnetic phase diagram of multiferroic Ca2CoSi2O7 for magnetic fields applied along the crystallographic [100]- and [001]-directions. The magneto-acoustic measurements were conducted for both longitudinal and transverse modes in both static and pulsed magnetic fields up to 17 and 68 T, respectively. Distinct anomalies with significant changes in sound velocity and sound attenuation were observed at the onset of the structural and magnetic phase transitions. Interestingly, results obtained for fields parallel to the [100]-direction reveal a hysteresis and step-like decrements in ultrasound indicating a transition into a different metastable structural distortion below TN and at magnetic fields between 4 and 10 T that has not been previously reported. We believe that this field-induced distorted structure phase may be the cause of the subsequent phase transition at 11 T. At low temperatures, a softening of the lattice within the ordered phases is also observed, which may be due to residual spin fluctuations.

Permalink: https://www.hzdr.de/publications/Publ-38105
Publ.-Id: 38105


In-depth Surface Studies of p-GaN:Cs Photocathodes by Combining Ex-Situ Analytical Methods with In-Situ X-Ray Photoelectron Spectroscopy

Schaber, J.

The photocathode is one of the key components of particle accelerator facilities that provides electrons for experiments in many disciplines such as biomedicine, security imaging, and condensed matter physics. The requirements for the electron-emitting material, the so-called photocathode, are rather high because these materials should provide a high quantum efficiency, a low thermal emittance, a fast response, and a long operational lifetime. At present, none of the state-of-the-art photocathodes can fully meet all the desired requirements. Therefore, new materials that can be used as potential photocathodes are urgently needed for future developments in accelerator research.
Semiconductor photocathodes such as cesium telluride are the preferred materials in particle accelerators. These photocathodes provide high quantum efficiencies of above 10 %, making them highly attractive. The crystal growth of cesium telluride, as a compound semiconductor photocathode, requires the deposition of cesium and tellurium on a suitable substrate with an ideal chemical ratio, which seems elaborate and difficult to handle.
In contrast, III-V semiconductors, such as gallium arsenide and gallium nitride (GaN), represent another type of semiconductor photocathode. These commercially available semiconductors are already grown on a substrate and only require a thin film of cesium and optional oxygen to obtain a photocathode. An atomically clean surface is necessary to achieve a negative electron affinity surface, which is the main prerequisite for high quantum efficiency.
In this work, p-GaN grown on sapphire by metal-organic chemical vapor deposition, was wet chemically cleaned, and transferred into an ultra-high vacuum chamber, where it underwent a subsequent thermal cleaning. The cleaned p-GaN samples were activated with Cs to obtain p-GaN:Cs photocathodes and their performance was monitored with respect to their quality, especially concerning their quantum efficiency and storage lifetime. The surface topography and morphology were examined ex-situ by atomic force microscopy and scanning electron microscopy in combination with energy dispersive X-ray spectroscopy.
Treatments at different temperatures resulted in various quantum efficiency values and storage lifetimes. Moderate temperatures of 400–500 °C were found to be more beneficial for the p-GaN surface quality, which was reflected by achieving higher quantum efficiency values. After the thermal cleaning, the samples were activated with a thin layer of cesium at an average pressure of 1 x 10-9 mbar. The surface morphology was studied with scanning electron microscopy and energy dispersive X-ray spectroscopy after the samples were thermally cleaned and activated with cesium. The results showed that the surface appeared inhomogeneous when the samples were cleaned at a high temperature above 600 °C. A thermal cleaning from the back side through the substrate represented another possibility but did not yield higher quantum efficiency values.
An in-situ analysis method facilitates following and understanding the changes in the surface electronic states before, during, and after any treatment of p-GaN:Cs photocathodes. For this purpose, an X-ray photoelectron spectrometer was applied that was built into an ultra-high vacuum system to prepare and characterize photocathodes. It allowed the in-situ monitoring of the photocathode surfaces beginning immediately after their cleaning and throughout the activation and degradation processes.
The realization of the adaption of an X-ray photoelectron spectroscopy chamber to the preparation chamber presented a significant constructional challenge. Thus, this work paid special attention to the technical aspects of in-situ sample transportation between these chambers without leaving the ultra-high vacuum environment.
The p-GaN surface was cleaned with different solutions and studied by X-ray photoelectron spectroscopy and atomic force microscopy, revealing that cleaning with a so-called "piranha" solution in combination with rinsing in ethanol works best for the p-GaN surface. A cleaning step that solely uses ethanol is also possible and represents a simple cleaning procedure that is manageable in all laboratories. Afterward, the cleaned p-GaN samples underwent a subsequential thermal vacuum cleaning at various temperatures to achieve an atomically clean surface. Each treatment step was followed by X-ray photoelectron spectroscopy analysis without leaving the ultra-high vacuum environment, revealing residual oxygen and carbon on the p- GaN surface. A thermal treatment under vacuum did not entirely remove these organic contaminations, although the thermal cleaning reduced their peak intensities. The remaining oxygen and carbon contaminants were assumed to be residuals derived from the metal-organic chemical vapor deposition process.
After the cesium activation, a shift toward a higher binding energy was observed in the X-ray photoelectron spectroscopy spectra of the related photoemission peaks. This shift indicated that the cesium was successfully adsorbed to the p-GaN surface. Before the cesium activation, adventitious carbon at a binding energy of approximately 284 eV was found, which was also present after the cesium activation but did not shift in its binding energy. It was also shown that the presence of remaining carbon significantly influenced the photocathode’s quality. After the cesium deposition, a new carbon species at a higher binding energy (approximately 286 eV) appeared in the carbon 1s spectrum. This new species showed a higher binding energy than adventitious carbon and was identified as a cesium carbide species. This cesium carbide species grew over time, resulting in islands on the surface. The X-ray photoelectron spectroscopy data facilitated the elucidation of the critical role of thiscesium carbide species in photocathode degradation.

Typically, the quantum efficiency of photocathodes decays exponentially. Conversely, an immense quantum efficiency loss was observed after the p-GaN:Cs photocathodes were studied by X-ray photoelectron spectroscopy. The origin of the quantum efficiency loss derived from X-rays as an external influence and was not caused by the sample’s transportation. Therefore, potential X-ray damages to the p-GaN:Cs photocathodes were investigated. These experiments showed that the adsorbed cesium and its adhesion to the p-GaN surface were strongly influenced by X-ray irradiation. The cesium photoemission peaks shifted toward a lower binding energy, while the relative cesium concentration did not. This shift indicated that X-ray irradiation accelerated the external aging of the p-GaN photocathodes and thus it was proposed to use lower X-ray beam power or cool the samples to prevent X-ray damage to cesiated photocathodes.
This work shows that an exclusive activation with cesium is feasible and that a re-activation of the same sample is possible. Quantum efficiency values of 1–12% were achieved when the p-GaN, grown on sapphire, was activated. The capability of an X-ray photoelectron spectroscopy analysis allowed the in-situ monitoring of the photocathode surface and shed light on the surface compositions that changed during the photocathodes’ degradation process.

Keywords: GaN photocathode; III-V photocathode; surface cleaning; Cs deposition; high quantum efficiency; surface studies

Related publications

Permalink: https://www.hzdr.de/publications/Publ-38104
Publ.-Id: 38104


Non-Fermi-Liquid Behavior of Superconducting SnH4

Troyan, I. A.; Semenok, D. V.; Ivanova, A. G.; Sadakov, A. V.; Zhou, D.; Kvashnin, A. G.; Kruglov, I. A.; Sobolevskiy, O. A.; Lyubutina, M. V.; Perekalin, D. S.; Helm, T.; Tozer, S. W.; Bykov, M.; Goncharov, A. F.; Pudalov, V. M.; Lyubutin, I. S.

The chemical interaction of Sn with H2 by X-ray diffraction methods at pressures of 180–210 GPa is studied. A previously unknown tetrahydride SnH4 with a cubic structure (fcc) exhibiting superconducting properties below TC = 72 K is obtained; the formation of a high molecular C2/m-SnH14 superhydride and several lower hydrides, fcc SnH2, and C2-Sn12H18, is also detected. The temperature dependence of critical current density JC(T) in SnH4 yields the superconducting gap 2Δ(0) = 21.6 meV at 180 GPa. SnH4 has unusual behavior in strong magnetic fields: B,T-linear dependences of magnetoresistance and the upper critical magnetic field BC2(T) ∝ (TC–T). The latter contradicts the Wertheimer–Helfand–Hohenberg model developed for conventional superconductors. Along with this, the temperature dependence of electrical resistance of fcc SnH4 in non-superconducting state exhibits a deviation from what is expected for phonon-mediated scattering described by the Bloch-Grüneisen model and is beyond the framework of the Fermi liquid theory. Such anomalies occur for many superhydrides, making them much closer to cuprates than previously believed.

Permalink: https://www.hzdr.de/publications/Publ-38103
Publ.-Id: 38103


Optimal control with a multidimensional quantum invariant

Modesto, O.-R.; Selwyn, S.; Sahra, A. K.; Samuel, J. H.; Winfried, K. H.; Mintert, F.

Optimal quantum control of continuous variable systems poses a formidable computational challenge because of the high-dimensional character of the system dynamics. The framework of quantum invariants can significantly reduce the complexity of such problems, but it requires the knowledge of an invariant compatible with the Hamiltonian of the system in question. We explore the potential of a Gaussian invariant that is suitable for quadratic Hamiltonians with any given number of motional degrees of freedom for quantum optimal control problems that are inspired by current challenges in ground-state to ground-state shuttling of trapped ions.

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Permalink: https://www.hzdr.de/publications/Publ-38102
Publ.-Id: 38102


Production of medical radionuclides in the Center for Radiopharmaceutical Tumor Research – a status report

Kreller, M.; Walther, M.; Brühlmann, S. A.; Knieß, T.; Kopka, K.

A new Center for Radiopharmaceutical Cancer Research was established at the Helmholtz-Zentrum Dresden-Rossendorf in order to centralize radionuclide production, radiopharmaceutical production and the chemical and biochemical research facilities in 2017. A routine production of several radionuclides was established during the last years. We report about the production methods of metallic and standard PET radionuclides like 11C, 18F, 123I, 64Cu, 67Cu, 67Ga, 131Ba and 131La that are done regularly. In the conclusion we report typical irradiation parameters and achieved saturation yields.

Keywords: cyclotrons; radioisotope production; production targets; target chemistry; theragnostics

Permalink: https://www.hzdr.de/publications/Publ-38101
Publ.-Id: 38101


Fast optomechanical photon blockade

Yuxun, L.; Sofia, Q.; Mintert, F.

The photon blockade effect is commonly exploited in the development of single-photon sources. While the photon blockade effect could be used to prepare high-fidelity single-photon states in idealized regimes, practical implementations in optomechanical systems suffer from an interplay of competing processes. Here we derive a control scheme that exploits destructive interference of Fock state amplitudes of more than one photon. The resulting preparation time for photon-blockaded quantum states is limited only by the optomechanical interaction strength and can thus be orders of magnitude shorter than in existing schemes that achieve photon blockade in the steady state.

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Permalink: https://www.hzdr.de/publications/Publ-38100
Publ.-Id: 38100


First Principles Investigation on Structural and Optoelectronic Properties of newly designed Janus Lead Halides PbXY (X, Y = F, Cl, Br, I )

Sudheer, A. E.; Tejaswini, G.; Devaraj, M.; Posselt, M.

Inspired by the beauty in the asymmetry, we design a novel class of Janus structures PbXY (X,Y = F, Cl, Br, I) and propose it for the solar mediated photocatalytic water splitting hydrogen production as well as for the photovoltaic solarcell applications.These novel Janus structures show large modulation in layer thickness, bond lengths and bond angles due to asymmetry of two sides. Charge analysis shows that covalent bonding for less electronegative atoms (I and Br) and ionic bonding for more electronegative (Cl and F) atoms. Strong dual bonding like ionic one side and covalent other side is observed when heavy and lighter atoms are part of the same Janus structures. The as designed Janus structures show good dynamical stability through phonon calculations. Basic electronic structure using Generalised Gradient Approximation (GGA) reveal both direct and indirect nature of band gap with large tunability
varying from 2.5 to 3.5 eV. Such a large tunability of band gap can be exploitedfor multifunctional applications. Heyd-Scuseria-Ernzerhof (HSE) electronic structure calculations are performed for more accuracy and wider band gaps are predicted for these Janus structures. The calculated electron and hole effective masses show robust charge carrier dynamics. The orbital resolved electronic density of states (DOS) shows that the conduction band edge is composed of pz orbital of Pb atom. The partial charge density calculated at conduction band minimum (CBM) also support the result obtained from PDOS analysis. Breaking of centrosymmetry, covalent bonding along z-direction, polarization in the out of plane direction, the z-oriented orbitals of CBM all points that these materials are suitable for shift current generation. The calculated optical absorption spectra show that the Janus structures are suitable for visible light absorption. The calculated potential difference between the top and bottom layer show significant variation and maximum (1.02 eV) is observed for PbClF. Further, we show that combining both potential difference and HSE bandgap, valence band maximum (VBM) and CBM straddle the water redox potentials, thus making the Janus structures suitable for hydrogen evolution reaction (HER) and oxygen evolution reactions (OER) on the opposite sides of the Janus structures.

Keywords: 2D materials; Janus Lead Halides; First-principle study

Permalink: https://www.hzdr.de/publications/Publ-38099
Publ.-Id: 38099


Random Quantum Neural Networks for Noisy Image Recognition

Konar, D.; Gelenbe, E.; Bhandary, S.; Das Sarma, A.; Cangi, A.

The application of classical Random Neural Networks (RNN) has been restricted to deterministic digital systems that generate probability distributions instead of the stochastic characteristics of random spiking signals. To optimize the utilization of the stochastic properties inherent in RNN, we propose a new category of supervised Random Quantum Neural Networks (RQNN) that incorporate a resilient training methodology. The RQNN under consideration utilizes a combination of classical and quantum algorithms, incorporating superposition state and angle encoding characteristics that draw inspiration from quantum information theory. Additionally, the model incorporates the stochastic random spiking property of neuron information encoding, which is known to exhibit spatial-temporal features similar to those observed in the brain. The proposed RQNN model has undergone thorough validation, relying on hybrid classical-quantum algorithms through a real IBM quantum processor. The proposed RQNN model is tested on the MNIST, Fashion-MNIST, and KMNIST datasets. The results indicate that it achieved an average classification accuracy of 59.6% when presented with unseen noisy test images. The experimental results demonstrate the efficacy and robustness of the proposed RQNN in classifying noisy images that have not been previously encountered.

Keywords: Recurrent neural networks; Computational modeling; Stochastic processes; Encoding; Robustness

  • Contribution to proceedings
    2023 IEEE International Conference on Quantum Computing and Engineering (QCE), 17.-22.09.2023, Bellevue, USA
    2023 IEEE International Conference on Quantum Computing and Engineering (QCE), 276
    DOI: 10.1109/QCE57702.2023.10240

Permalink: https://www.hzdr.de/publications/Publ-38098
Publ.-Id: 38098


Characterization of Magnetic and Mineralogical Properties of Slag Particles from WEEE Processing

Siddique, A.; Boelens, P.; Long, F.; Zhou, S.; Cnudde, V.; Leißner, T.

Magnetic separation has wide-ranging applications in both mineral processing and recycling
industries. Nevertheless, its conventional utilization often overlooks the interplay between
mineral and particle characteristics and their impact on operational conditions, ultimately influencing
the efficacy of the separation process. This work describes a methodology able to achieve
the comprehensive characterization and classification of Waste Electrical and Electronic Equipment
(WEEE) slag. The primary objective is to establish a meaningful connection between the distinct
properties of slag phases and their influence on the separation process. Our methodology consists
of several stages. Firstly, the WEEE slag is sieved into distinct size classes, followed by classification
into magnetic susceptibility classes by using the Frantz Isodynamic separator. To quantify the
magnetic susceptibility of each class, we used a magnetic susceptibility balance, and to identify
paramagnetic and ferromagnetic fractions and phases within these magnetic susceptibility classes,
we conducted vibrating-sample magnetometer measurements. Finally, to establish a meaningful link
between the magnetic characterization, mineralogical, and particle-level details, Mineral Liberation
Analysis was conducted for each magnetic susceptibility class. This in-depth analysis, encompassing
both particle properties and magnetic susceptibility classes, provides a better understanding of
the separation behavior of different phases and can help to enrich phases with a specific range of
magnetic susceptibility values. This knowledge advances progress towards the development of
predictive separation models that are capable of bridging the gap between theoretical understanding
and practical application in the field of magnetic separation.

Keywords: magnetic characterization; magnetic susceptibility classes; WEEE slag; vibrating-sample magnetometer (VSM)

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Permalink: https://www.hzdr.de/publications/Publ-38097
Publ.-Id: 38097


Compressing simulation output with cINNs and continual learning

Willmann, A.; Schmerler, S.; Ebert, J.; Kesselheim, S.; Bussmann, M.; Chandrasekaran, S.; Debus, A.; Hoffmann, N.; Holsapple, K.; Juckeland, G.; Pausch, R.; Pöschel, F.; Schramm, U.; Steiniger, K.

The output of simulations can be extremely challenging to work with. For example, in large-scale particle-in-cell simulations in plasma physics, trillions of particles are simulated over millions of time steps, creating Petabytes of data. In this project, we develop methods to compress particle data by training conditional invertible neural networks (cINNs) on the particle data. The particles then can be reconstructed by running the trained model in generative mode. This allows us to reach up to millionfold compression, and a controlled loss of a accuracy. The models can be conditioned not only on the temporal axis but also on other types of simulation outputs of smaller data volume, leading potentially to even higher compression factors.

In order to enable the neural network model to represent simulation data over long time spans, we apply methods from Continual Learning, where each new learning task is represented by a dataset produced by a simulation time step. This approach enables us to efficiently solve the inverse problem of particle data reconstruction from radiation data in a time-resolved manner by side-stepping demanding simulations.

  • Poster
    Helmholtz AI Conference 2023, 12.-14.06.2023, Hamburg, Germany

Permalink: https://www.hzdr.de/publications/Publ-38096
Publ.-Id: 38096


Rohstoffe aus der Lampe

Boelens, P.; Lederer, F.

Rohstoffe aus der Lampe - ein biotechnologischer Ansatz für ein umweltfreundliches Recycling von Hochtechnologiemetallen

  • Invited lecture (Conferences)
    Lange Nacht der Wissenschaften Dresden, 30.06.2023, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-38095
Publ.-Id: 38095


Peptide-based biomagnetic separation for the recycling of critical raw materials from ultrafine particles in complex waste streams

Boelens, P.; Lederer, F.

In the global transition towards a low-carbon economy, the current dependence of fossil fuels is rapidly replaced by an increased demand in critical raw materials (CRMs). For example, rare-earth elements (REEs) play an essential role in the large-scale electrification, due to their requirement for the production of permanent magnets, lamp phosphors and rechargeable batteries [1]. However, the REEs’ supply chain is under a high pressure due to a combination of the rising demand, a monopolistic market structure and very low overall recycling rates [2]. The Helmholtz Institute Freiberg for Resource Technology (HIF) aims to promote the energy transition by developing innovative methods and technologies along entire material cycles, ranging from the exploration, to the recycling of CRMs. In this context, the application of biotechnological methods (such as biosorption, bioleaching and biocomplexation) could offer feasible and green solutions for the recycling of complex waste streams, resulting in increased recycling rates of CRMs [3].

At the HIF, the junior research group BioKollekt aims to develop a feasible and upscalable biomagnetic separation method for a novel recycling process of CRMs in the form of ultrafine particles. As a proof of concept, we are currently focussing on the recycling of REEs from fluorescent lamp phosphors. We have identified surface binding peptides, i.e. a type of biomolecules, that selectively bind to the green phosphor LaPO4:Ce,Tb [4]. Subsequently, we have functionalized various magnetic carriers, such as composite beads, core-shell magnetic nanoparticles and bacterial magnetosomes, with the identified peptides. The obtained bifunctional materials (due to their 1) highly selective binding to target particles and 2) high response to an external magnetic field) are ideal carriers to facilitate a separation in challenging waste streams. Finally, using the target materials, we have conducted lab-scale binding experiments, as well as, upscalable separation experiments in a high-gradient magnetic separator (HGMS) [5,6]. In the coming period, we will work to develop an integrated multistep separation process for REE phosphors and explore the possibilities to expand our method to other waste streams.

Keywords: Establish and assess a secure and sustainable energy and raw materials supply

  • Lecture (Conference)
    Helmholtz Energy Conference 2023, 12.-13.06.2023, Koblenz, Germany

Permalink: https://www.hzdr.de/publications/Publ-38094
Publ.-Id: 38094


Impact of Quaternary Glaciations on Denudation Rates in North Pamir—Tian Shan Inferred From Cosmogenic 10Be and Low-Temperature Thermochronology

Kudriavtseva, A.; Codilean, A. T.; Sobel, E. R.; Landgraf, A.; Fülöp, R.-H.; Dzhumabaeva, A.; Abdrakhmatov, K.; Wilcken, K. M.; Schildgen, T.; Fink, D.; Fujioka, T.; Gong, L.; Rosenwinkel, S.; Merchel, S.; Rugel, G.

We explore the spatial and temporal variations in denudation rates in the northern Pamir—Tian Shan region using 10Be-derived denudation rates from modern (n = 110) and buried sediment (2.0–2.7 Ma; n = 3), and long-term exhumation rates from published apatite fission track (AFT; n = 705) and apatite (U-Th-Sm)/He (AHe; n = 211) thermochronology. We found moderate correlations between denudation rates and topographic metrics and weak correlations between denudation rates and annual rainfall, highlighting complex linkages among tectonics, climate, and surface processes that vary locally. The 10Be data show a spatial trend of decreasing modern denudation rates from west to east, suggesting that deformation and precipitation control denudation in the northern Pamir and western Tian Shan. Farther east, the denudational response of the landscape to Quaternary glaciations is more pronounced and reflected in our data. Modern 10Be denudation rates are generally higher than the long-term AFT and AHe exhumation rates across the studied area. In the Kyrgyz Tian Shan, on average, the highest 10Be denudation rates are recorded in the Terskey range, south of Lake Issyk-Kul. Here, modern denudation rates are higher than 10Be-derived paleo-denudation rates, which are comparable in magnitude with the long-term exhumation rates inferred from AFT and AHe. We propose that denudation in the region, particularly in the Terskey range, remained relatively steady during the Neogene and early Pleistocene. Denudation increased due to glacial-interglacial cycles in the Quaternary, but this occurred after the onset and intensification of the Northern Hemisphere glaciations at 2.7 Ma.

Related publications

  • Open Access Logo Journal of Geophysical Research - Earth Surface 128(2023)12, e2023JF007193
    DOI: 10.1029/2023JF007193

Permalink: https://www.hzdr.de/publications/Publ-38093
Publ.-Id: 38093


Machine Learning-based Data Analysis and Surrogate Modeling For COXINEL Experiment

Willmann, A.; Ghaith, A.; Chang, Y.-Y.; Debus, A.; La Berge, M.; Labat, M.; Ufer, P.; Schöbel, S.; Hoffmann, N.; Bussmann, M.; Couprie, M.-E.; Schramm, U.; Irman, A.

Recently, free electron lasing at UV wavelength has been demonstrated by deploying the COXINEL beamline driven by HZDR plasma accelerator in a seeded configuration[1]. Further control and optimization of such an FEL radiation require full knowledge of strongly-coupled multivariate parameters involved in laser plasma acceleration, electron beam transport and radiation generation. For this purpose, one has to solve an inverse problem, i.e. finding matching parameters of the simulation to reproduce the experiment. Such inverse problems are ill-posed and cannot be easily resolved due to high computational complexity. Here, machine learning-based methods have a high potential to accelerate theoretical comprehension of the system, novel means for design space exploration and promise reliable in-situ analysis of experimental diagnostics and parameters. We apply simulation-based inference technique for this purpose. This method is a combination of deep learning and statistical approaches to resolve an inverse problem up to a posterior distribution of the simulation parameters given an experimental sample. In addition, we have developed machine learning-based surrogate models that can significantly accelerate forward computations for even faster results of the inverse solver.

[1] M. Labat, et al. "Seeded free-electron laser in driven by a compact laser plasma accelerator", Nat. Photonics, 17, 150(2023)

  • Open Access Logo Lecture (Conference)
    The 6th European Advanced Accelerator Concepts Workshop, 2023, 17.-23.09.2023, Isola d'Elba, Italy
  • Open Access Logo Poster
    The 6th European Advanced Accelerator Concepts Workshop, 2023, 17.-23.09.2023, Isola d'Elba, Italy
  • Open Access Logo Poster
    The 9th annual meeting of the programme "Matter and Technologies", 09.-11.10.2023, Karlsruhe Institute of Technology, Germany
  • Open Access Logo Poster
    Doctoral Seminar 2023, 17.-19.10.2023, Schillbach, Germany

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Permalink: https://www.hzdr.de/publications/Publ-38092
Publ.-Id: 38092


Implicit Convolutional Kernels for Steerable CNNs

Zhdanov, M.; Hoffmann, N.; Cesa, G.

Steerable convolutional neural networks (CNNs) provide a general framework for building neural networks equivariant to translations and transformations of an origin-preserving group G, such as reflections and rotations. They rely on standard convolutions with G-steerable kernels obtained by analytically solving the group-specific equivariance constraint imposed onto the kernel space. As the solution is tailored to a particular group G, implementing a kernel basis does not generalize to other symmetry transformations, complicating the development of general group equivariant models. We propose using implicit neural representation via multi-layer perceptrons (MLPs) to parameterize G-steerable kernels. The resulting framework offers a simple and flexible way to implement Steerable CNNs and generalizes to any group G for which a G-equivariant MLP can be built. We prove the effectiveness of our method on multiple tasks, including N-body simulations, point cloud classification and molecular property prediction.

Keywords: machine learning; equivariant networks; convolutional neural networks

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Permalink: https://www.hzdr.de/publications/Publ-38090
Publ.-Id: 38090


Prompt-Gamma-Imaging: Clinical application demonstrates potential for online-adaptive proton therapy

Berthold, J.

Treatment verification in proton therapy is important for 1) detecting anatomical changes during treatment 2) independent quality assurance during online-adaptive proton therapy (OAPT) and, hence, 3) potentially reducing safety margins. In this context, clinical Prompt-Gamma-Imaging (PGI) data were evaluated which demonstrated the potential of PGI for treatment verification.

  • Lecture (others)
    NCRO Retreat 2023, 04.-06.05.2023, Heidelberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38089
Publ.-Id: 38089


Data publication: Ab initio path integral Monte Carlo simulations of the uniform electron gas on large length scales

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

This repository contains the PIMC simulation results shown in the publication "Ab Initio Path Integral Monte Carlo Simulations of the Uniform Electron Gas on Large Length Scales"

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Permalink: https://www.hzdr.de/publications/Publ-38085
Publ.-Id: 38085


Data publication: The origin of native metal-arsenide mineralization in the world-class Schlema-Alberoda uranium deposit (Germany): Insights from arsenide compositions and fluid inclusion systematics

Guilcher, M.; Gutzmer, J.; Hiller, A.; Krause, J.; Blamey, N.; Härtel, B.; Burisch-Hassel, M.

This dataset contains the mineral descriptions, mineral chemical compositions and fluid inclusion data from the samples investigated in the study as well as the analytical parameters for the analytical methods used.

Keywords: Cobalt; Uranium; Arsenide; Fluid inclusion; Microthermometry; Crush-fast scan gas mass spectrometry; Erzgebirge; Five-element mineralization

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Permalink: https://www.hzdr.de/publications/Publ-38084
Publ.-Id: 38084


Comparative analysis of next-generation sequencing data generated from phage display trails with inorganic materials

Bloß, C.

The aim of this work is to find meaningful and statistical proven ways to identify metal binding peptides in multiple trail phage display experiments with inorganic materials.

Keywords: Biotechnology; Bioinformatics; Phage Surface Display; Next-Generation Sequencing; Statistical Analysis; Illumina; Data Science; Ressource Technology; Recycling

  • Open Access Logo Poster
    15th annual PEGS - Protein & Antibody Engineering Summit 2023, 13.-16.11.2023, Lissabon, portugal

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Permalink: https://www.hzdr.de/publications/Publ-38083
Publ.-Id: 38083


Recyclable pickering emulsions for enzymatic phenol degradation of oily wastewater

Gong, Z.; Gao, S.; Lu, K.; Hübner, R.; Wu, C.

Enzymatic degradation offers a sustainable solution for waterborne phenolic pollutants. However, its application within industrial, non-aqueous contexts — particularly in mitigating phenolic contaminants in oily wastewater — remains significantly challenging. To address this challenge, the present study exploits the potential of Fe3O4@PDA nanoparticles to form oil-in-water Pickering emulsions for the enzymatic degradation process. The uniform stability of the prepared emulsion, with droplet sizes under 5 μm, protects enzyme activity and expands the water-oil interfacial area, leading to an enhancement in the efficiency of horseradish peroxidase (HRP) catalytic degradation. The application of this emulsion resulted in a substantial increase in the degradation rate of phenol, achieving 100% within 30 min as opposed to an only 13.6% without it. The study also highlights the excellent stability, reusability, and versatility of the Fe3O4@PDA nanoparticles, enabled by magnetic separation and their ability to form emulsions with diverse oil phases. Consequently, our research offers valuable insights into the development of environmentally sustainable strategies for the degradation of phenolic contaminants in various industrial oily wastewater.

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Permalink: https://www.hzdr.de/publications/Publ-38080
Publ.-Id: 38080


Die Morphologie der Schuppen der aus der Paläarktis bekannten Arten der Unterfamilie Procridinae Boisduval, 1828 (Lepidoptera, Zygaenidae) und deren Bedeutung für die Systematik und Phylogenie

Keil, T.; Hübner, R.; Worbs, A.

In dieser Arbeit werden erstmals die Form und Gestaltung der Schuppen der meisten (>90 %) der aus der Paläarktis bekannten Arten der Unterfamilie Procridinae Boisduval, 1828 abgebildet und Möglichkeiten der Determinationsunterstützung sowie deren Bedeutung für phylogenetische Interpretationen in Verbindung mit anderen morphologischen Merkmalen diskutiert.

The morphology of the scales of the Palaearctic species of the subfamily Procridinae Boisduval, 1828 (Lepidoptera, Zygaenidae) and their importance for systematics and phylogeny. – The present publication illustrates morphology and design of the scales of most (>90 %) of the Palaearctic species of the subfamily Procridinae Boisduval, 1828 for the first time. Possible support of identifications and the importance for phylogenetic interpretations in combination with other morphological features are discussed.

Related publications

  • Entomologische Nachrichten und Berichte 67(2023)3, 181-201

Permalink: https://www.hzdr.de/publications/Publ-38079
Publ.-Id: 38079


Synthesis and characterization of titanium and aluminum complexes of 2-methoxybenzyl alcoholate and their use in base-catalyzed twin polymerization

Scharf, S.; Rüffer, T.; Formánek, P.; Hübner, R.; Weber, M.; Mehring, M.; Lang, H.

The synthesis and characterization of twin monomers [Ti(OCH2-2-MeO-C6H4)4(HOCH2-2-MeO-C6H4)]2 (3) and [Al(OCH2-2-MeO-C6H4)3]4 (5) by reacting HOCH2-2-MeO-C6H4 (1) with Ti(OiPr)4 (2), or 1 with AlMe3 (4) is discussed. Single crystal X-ray structure analysis of 3 shows a dimeric structure with two alkoxide ligands bridging the titanium ions, while the others are terminal bonded. The respective phenolic resin / metal oxide hybrid materials HM_Ti and HM_Al were obtained in moderate (HM_Ti) to excellent (HM_Al) yields using typical base-catalyzed twin polymerization conditions (230 °C, 2 h). Nuclear magnetic resonance and infrared spectroscopy as well as scanning electron microscopy and scanning transmission electron microscopy combined with energ-dispersive X-ray spectroscopy proved the formation of inorganic–organic hybrid materials consisting of resin and MxOy materials (HM_Ti, TiO2; HM_Al, Al2O3) containing interpenetrating phase nano-domains with sizes of < 5 nm, as is charcteristic for twin polymerization processes. Oxidation of HM_Ti and HM_Al yielded the respective oxide materials Ox_Ti (TiO2) and Ox_Al (Al2O3), which possess low surface areas of ABET = 53 m2/g and 76 m2/g, respectively.

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Permalink: https://www.hzdr.de/publications/Publ-38078
Publ.-Id: 38078


Complete Glucose Electrooxidation Enabled by Coordinatively Unsaturated Copper Sites in Metal-Organic Frameworks

Shi, X.; Ling, Y.; Li, Y.; Li, G.; Li, J.; Wang, L.; Min, F.; Hübner, R.; Yuan, S.; Zhan, J.; Cai, B.

The electrocatalytic oxidation of glucose plays a vital role in biomass conversion, renewable energy, and biosensors, but significant challenges remain to achieve high selectivity and high activity simultaneously. In this study, we present a novel approach for achieving complete glucose electrooxidation utilizing Cu-based metal-hydroxide-organic framework (Cu-MHOF) featuring coordinatively unsaturated Cu active sites. In contrast to traditional Cu(OH)2 catalysts, the Cu-MHOF exhibits a remarkable 40-fold increase in electrocatalytic activity for glucose oxidation, enabling exclusive oxidation of glucose into formate and carbonate as the final products. The critical role of open metal sites in enhancing the adsorption affinity of glucose and key intermediates was confirmed by control experiments and density functional theory simulations. Subsequently, a miniaturized nonenzymatic glucose sensor was developed showing superior performance with a high sensitivity of 214.7 μAmM-1cm-2, a wide detection range from 0.1 μM to 22 mM, and a low detection limit of 0.086 μM. Our work provides a novel molecule-level strategy for designing catalytically active sites and could inspire the development of novel metal-organic framework for next-generation electrochemical devices.

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Permalink: https://www.hzdr.de/publications/Publ-38077
Publ.-Id: 38077


PyPlaque: An Open-source Python Library for Phenotypic Analysis of Virus Plaque Assays

De, T.; Andriasyan, V.; Yakimovich, A.

Virological plaque assay is the primary way for the quantification of infectious virus particles in a virus suspension. It is performed by incubating a serial dilution of the virus inoculum with a monolayer of indicator cells. While some tools for automated quantification have been proposed in the past, they lack modularity and are often closed-source. PyPlaque is open-source software written in Python programming language for the analysis and quantification of plaque phenotypes that are observed in plaque assays by virologists. It is based on an abstract software architecture allowing to take into account glassware and specimen carriers and focus on phenotype-specific information. This, in turn, allows biologist to construct modular and simple program code that follows the logical flow of the experimental design and desired quantification outcomes. Furthermore, we demonstrate the comparability of PyPlaque to existing software and show how phenotype-based abstraction allows for seamless coding using Pythonic conventions.

Keywords: plaque assays; viral quantification; automated masking; image and object quantification

  • Poster
    ScaDS.AI 9th International Summer School on AI and Big Data, 03.07.2023, Dresden, Germany
  • Poster
    PoL BioImage Analysis Symposium 2023, 30.08.2023, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-38076
Publ.-Id: 38076


Silicon anode processing using flash lamp annealing for lithium ion batteries

Cherkouk, C.; Folgner, C.; Worbs, A.; Hübner, R.; Prucnal, S.; Schumann, T.; Krüger, S.; Zhou, S.; Rebohle, L.

In the near future, silicon will play a key role as anode material for rechargeable lithium ion batteries (LIBs). It shows a low discharge potential and an extremely high specific theoretical capacity of about 4200 mAhg-1 in comparison to that of graphite with a theoretical capacity of 370 mAhg-1. However, the intrinsic volume change of Si particles of more than 400 % during the lithiation and delithiation processes hinders the Si to fully replace the conventional graphite in commercial LIBs. Using planar flash-lamp annealing (FLA) with annealing times in the sub-second range directly after the deposition of a Si thin film on a copper foil, we fabricated a copper silicide anode (CuSi-anode) with outstanding electrical and electrochemical properties. Herein, structural investigations using scanning electron microscopy and X-ray diffraction show a Cu-mediated silicidation at generating mixed phases of copper silicides, SiOx, Cu, and Si nanoparticles. The performance of battery cells with CuSi-anode having a Si thickness of 5 µm versus LiFePO4 shows a surface capacity of 2mAh/cm2 over 100 cycles with capacity loss in the course of cycling but with good electrical conductivity between the anode and current collector. Finally, we compare the electrochemical performance of the CuSi-anode with a conventional graphite anode at the same cell configuration and chemical conditions.

Keywords: Silicon anode; lithium ion batteries; copper silicide anode; flash-lamp annealing; FLA

  • Poster
    AABC Europe: Advanced Automotive Battery Conference, 19.-22.06.2023, Mainz, Germany

Permalink: https://www.hzdr.de/publications/Publ-38074
Publ.-Id: 38074


recomine: Technologies and concepts for a holistic mine waste treatment made in Saxony

Büttner, P.; Engelhardt, J.

recomine is an alliance of predominantly regional partners from industry, science and society in the Erzgebirge (Saxony/Germany). The alliance is funded by the German Federal Ministry of Education and Research (BMBF) since 2018 with a total of €12.7 million and is coordinated by the Helmholtz Institute Freiberg for Resource Technology. With the vision of developing innovative and holistic solutions for mining waste, recomine supports R&D projects that address the intersection of environmental technology, resource technology, Industry 4.0 and social issues. The aim is to bring regional know-how at real development sites together. The Davidschacht tailing in Freiberg is such a site that allows testing new solutions under real conditions. The necessity of innovative technologies is illustrated the new Global Industry Standard on Tailings Management published in 2020 by the International Council on Mining & Metals (ICMM). It was developed in response to recent devastating tailings accidents (e.g. Brumadinho/Brazil in 2019) and is based on the "Zero Harm" principle. Numerous activities of large mining companies (e.g. BPH, Vale, Rio Tinto) started to promote the development of new approaches as a consequence of the new standard. In 2021, for example, the BHP Tailings Challenge called the global raw material community to submit concepts for the recycling and reduction of mining waste from a large copper mine. recomine succeeded in being among the ten selected from over 150 teams. These teams had to proof their submitted recycling concept in a first phase of the challenge. This success is now being continued, e.g. in a project for Amira, a global not-for-profit organization representing members from the resources industry, which is currently being prepared. Direct R&D agreements with mining companies are also under negotiation. recomine's long-term goal is to act as a bridge between regional know-how providers and the global mining industry. The developed technologies can be divided into four groups: analysis, avoidance, remining and transformation. While new technologies for the characterization of tailings or mine water play a role in the area of analysis, the area of avoidance deals with technologies to minimize fine-grained tailings in primary ore processing (e.g. machine-learning optimized sensor-based sorting). In remining, processing technologies are developed to recover the remaining metals, even from the previously undevelopable grain size ranges, e.g. by further development of pneumatic flotation. The Transformation then deals with the use of mining waste, e.g. in the building materials sector, and also provides new approaches to renaturation.

Keywords: recomine; remining; mine waste; tailings; Circular economy; HIF

  • Lecture (Conference)
    WISSYM 2023 - 5. Internationales Bergbausymposium, 25.-28.09.2023, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38072
Publ.-Id: 38072


recomine: Environmental technologies for the development of disperse raw material sources

Büttner, P.

Under the umbrella of recomine 18 R&D projects are running today. The presentation shows the results and the goal of recomine to develop holistic solutions for mining waste.

Keywords: recomine; remining; HIF; Recycling; Circular economy

  • Invited lecture (Conferences)
    PDAC German Day “Shaping the Future of Resources – German Canadian Partnerships in Times of Transformation”, 07.03.2023, Toronto, Kanada

Permalink: https://www.hzdr.de/publications/Publ-38071
Publ.-Id: 38071


Data publication: Effect of ISA and chloride on the uptake of niobium(V) by hardened cement paste and C-S-H phases: quantitative description and mechanistic understanding

Jo, Y.; Çevirim-Papaioannou, N.; Franke, K.; Fuss, M.; Pedersen, M.; Lothenbach, B.; de Blochouse, B.; Altmaier, M.; Gaona, X.

This dataset is a report about gamma spectroscopy measurement of the irradiated cyclotron target generated by GammaVision software (ORTEC/AMETEK, Version 8.00.03).

Keywords: niobium; cyclotron; gamma spectroscopy

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Permalink: https://www.hzdr.de/publications/Publ-38070
Publ.-Id: 38070


Nonlinear response of semiconductor under intense THz excitation

Pashkin, O.

Intense narrowband terahertz pulses from the FELBE free-electron laser facility and a complementary table-top high-field THz source are utilized to study nonlinear excitation regimes in semiconductors. In this talk we present several recent examples including impurities transitions in boron doped Si, HgTe topological quantum wells and plasmons in individual InGaAs nanowires.

Related publications

  • Invited lecture (Conferences)
    Joint ELI Workshop on Advanced Technologies, 04.-06.12.2023, Szeged, Hungary

Permalink: https://www.hzdr.de/publications/Publ-38069
Publ.-Id: 38069


AutoTarget : Autonomous Multi-UAV (Unmanned Aerial Vehicle) for the Characterization of Remote and Isolated Targets

Adoni, W. Y. H.; Shaik Fareedh, J.; Lorenz, S.; Gloaguen, R.; Kühne, T. D.-S.

This research focus on the development of an autonomous multi-UAV (Unmanned Aerial Vehicles) system, capable of performing target detection and characterization via a domaining approach. The core concept lies in the distribution of tasks to at least two communicating UAVs with specified capabilities (UAV1 and UAV n), flying at the same time. The obtained results are processed in (near- )real time to property maps and passed to the operator by UAV 1 for further interpretation and decision-making. With this concept, the multi-UAV approach allows the fast detection and characterization of isolated, remote targets in a time and resource efficient manner. As high- dimensional / high-detail data is only acquired where it matters, large volumes of superfluous data can be avoided from the start, and such, processing time and computational requirements are reduced. In parallel, the knowledge on the targets’ properties can be tremendously increased for more accurate and detailed characterization as well as the avoidance of false positives. The targeted multi-drone approach further decreases the impact of the survey on environment, wildlife, and population by reducing the necessary impact to a minimum as well as the flight time.

Keywords: Unmanned Aerial Vehicle (UAV); Uncrewed Aerial Vehicle; Autonomous Swarm; Collaborative Mission; Autonomous Aerial Vehicle; Autonomous Aerial Swarm; Drones

  • Open Access Logo Lecture (Conference)
    2023 HZDR Science Conference, 15.-16.11.2023, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany

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Permalink: https://www.hzdr.de/publications/Publ-38067
Publ.-Id: 38067


Concept and Design of Intelligent Swarm for Distributed Mission

Adoni, W. Y. H.; Shaik Fareedh, J.; Lorenz, S.; Gloaguen, R.; Kühne, T. D.-S.

Single drones have been already used for basic missions. Drone swarms have further extended advantages as they can cover much larger areas in shorter times. In accordance with the requirements in terms of demand, it is possible to carry out various missions involving several types of UAVs as well as various onboard sensors. This task becomes even more complex when the system is composed of autonomous UAVs that collaborate with each other without the assistance of an operator. Several factors must be considered, such as the complexity of the mission, the types of UAVs, the communication architecture, the routing protocol, the coordination of tasks, and many other factors related to the environment. In this proposal, we will discuss the conceptual model and implementation of a multi-UAV system based on a decentralized master-slave architecture. We will then discuss the development environment using tools such as the ROS, MAVLINK, Gazebo, MavProxy/APM/QGround. We will address the communication concerns between UAVs that underlie the messages, services and actions enabling efficient swarm interation. Finally, we'll discuss the technical challenges and constraints involved in setting up such a project.

Keywords: Unmanned Aerial Vehicle (UAV); Uncrewed Aerial Vehicle; Autonomous Swarm; Collaborative Mission; Autonomous Aerial Vehicle; Autonomous Aerial Swarm; Drones

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  • Open Access Logo Lecture (Conference)
    PX4 autopilot Developer Summit 2023, 21.-22.10.2023, New Orleans, LA, USA

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Permalink: https://www.hzdr.de/publications/Publ-38066
Publ.-Id: 38066


Removal of antibiotic resistance genes from wastewater using diethylaminoethyl cellulose as a promising adsorbent

Pant, A.; Jain, R.; Ahammad, S. Z.; Ali, S. W.

The implications associated with the emergence of antibiotic resistance genes (ARGs) are dangerous, and there is an urgent need for their effective removal from the environment. The current study is a comprehensive evaluation of the potential of diethylaminoethyl cellulose (DEAE-C) to target the adsorptive removal of ARGs using a template DNA under different working conditions like varying adsorbate concentrations, time, working pH, coexisting anions and real waste water matrix. The obtained results exhibited excellent adsorption efficiency of DEAE-C with high Langmuir maximum adsorption capacity of 65.40 μg/mg at pH 7 ± 0.5. The adsorption process was majorly governed by the electrostatic force of attraction. Desorption study was performed for the adsorbent reusability. Maximum desorption was attained at pH 8 ± 0.5 using 2 ml 0.5 M NaCl. The adsorbent exhibited great recyclability up to 10 regeneration

Keywords: AMR; Wastewater; adsorption; antibiotics

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Permalink: https://www.hzdr.de/publications/Publ-38065
Publ.-Id: 38065


Siderophores assisted recovery of critical metals from mining residues

Jain, R.; Pollmann, K.; Ghosh, A.; Dhiman, S.; Mondol, P.; Jain, P.

Critical raw materials (CRM) such as gallium (Ga), germanium (Ge), indium (In) are necessary for the development of high-tech and low carbon emission technologies such as photovoltaics, fiber optics cable, liquid crystal display and light emitting diodes. The supply of these CRM is not assured in future due to several reasons. One of the ways to overcome this shortage is through CRM recovery from low concentrated mining/urban wastes. However, such a recovery is impeded because of high concentration of contaminants and very low concentration of the CRM. Thus, a sensitive and specific process is needed.
Siderophores are highly selective molecules towads Fe(III) and their this selectivitiy is also extended towards other CRM. Thus, the siderphores, desferrioxamine B (DFOB), has been exploited for the recovery of these CRMs from different wastes. The complexation of free DFOB with Ga and Ge was investigated. pH and ionic strength has no effect on the DFOB complexation with Ga while Ge showed much better complexity at low pH values and higher ionic stregth. There was again little to no effect of anions on the DFOB complexation with Ga while DFOB complexation with Ge increased with the increase in presence of anions. The EDTA was able to completely decomplex both Ga-DFOB and Ge-DFOB complexes.

For the technology development, DFOB was immobilized onto the solid-matrix with the free NH3 tail. The optimized length of the linker was needed for the successful immobilization of DFOB. Maximum of 3 - 6 mg of Ga/Ge/In per g of the DFOB immobilized solid matrix was achieved during batch adsorption studies. In the next steps, DFOB immobilized solid-matrix was packed in the column and the technology was demonstrated at 10 L/day and 100 L/day capacity with the real wastewater from the wafer manufacturing company. Maximization of the flow rate and identification of the upscaling parameters was carried out. Further, flowsheet were developed with pretreatment for the recovery of Ga and Ge from the mining residues. The GaLIophore techology is already patented and has potential to economically recover CRM from low concentrated wastes/wastewater with much lower environmental impact compared to traditional processes.

Keywords: Critical metals; Siderophores; GaLIophore; scale-up; Mining residues

  • Lecture (Conference)
    Goldschmidt 2023, 09.-14.07.2023, English, France

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Permalink: https://www.hzdr.de/publications/Publ-38064
Publ.-Id: 38064


Numerical Investigation of Liquid-Solid Flow Dynamics in an Oscillatory Baffled Reactor

Mondol, P.; Ambekar, A. S.; Jain, R.; Ahammad, S. Z.

The oscillatory baffled reactor (OBR) is widely used in the chemical and biochemical industry to perform solid-catalyzed reactions such as fermentation, leaching, polymerization, etc., and is a good reactor intensification strategy. The overall performance of these reactors depends on the dynamics of the spatial distribution of micron-scale catalyst particles. The spatial distribution of the particles is not only a function of the physical properties of the solid and liquid phase but also a function of baffle geometry and oscillatory conditions [i.e., frequency and amplitude], which substantially influences the hydrodynamics of OBR. To the best of the author's knowledge, the hydrodynamics of OBR, in the presence of particles is not investigated. In view of the above, we investigate the hydrodynamics of OBR, in the presence of particles, with the aid of a 3D two-fluid Eulerian-Eulerian approach combined with the kinetic theory of granular flow (EE-KTGF). Before using the simulations to investigate the hydrodynamics for a wide range of conditions, the predictions of EE-KTGF were validated with aid of measurements in terms of mixing/settling time as a function of solid properties. The validated model is further used to understand the role of particle size (10 to 100 µm), density (1100 to 2200 kg/m3), and (0.833 to 1.583 Hz) on the local liquid-solid hydrodynamics. The predictions demonstrate that, at a high, small particle size and density, recirculatory vortices are formed, aiding uniform radial mixing. However, at low, large particle sizes, and densities, local dead zones start appearing leading to the sedimentation of particles. The presented hydrodynamics predictions provide a useful basis for further intensification of liquid-solid OBRs.

Keywords: Oscillatory baffled reactor; hydrodynamics; solid-liquid separation; CFD

  • Lecture (Conference)
    Fluidization 2023, 21.-25.05.2023, English, Unites States

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Permalink: https://www.hzdr.de/publications/Publ-38063
Publ.-Id: 38063


Mineralogy and critical metal deportment of Fe-Ni-Co laterite ores from Sebuku Island, SE Kalimantan, Indonesia

Giorno, M. A.; Kontonikas-Charos, A.; Ebert, D.; Krause, J.; Möckel, R.; Sandmann, D.; Burisch, M.; Ernowo, E.; Idrus, A.; Swamidharma, Y.; Krisnanto, Y.; Frenzel, M.

Laterite deposits in Indonesia are a major source of Ni and Co. Here, we present new geological data on the Sebuku laterite deposit (Island of Sebuku, SE Kalimantan, Indonesia), with a JORC-compliant resource of ~390 Mt at 42.5 wt.% Fe, 0.9 wt.% Ni, and 0.15 wt.% Co. The laterites are mostly limonitic, oxide-dominated Fe-Ni-Co (±Sc)-rich horizons, which formed by weathering of Jurassic-Cretaceous ophiolitic units. Although the deposit is under production since 2006 (primarily for Fe), there is little mineralogical and geochemical data available, which would allow optimizing beneficiation and recovery of Ni, Co, and Sc.
Typical laterite profiles at Sebuku consist of: 1) weathered bedrock composed of serpentinized dunites and harzburgites overlain by 2) a 0.2-7 m-thick saprolite zone, 3) a 2-8.5 m-thick yellow limonite zone, and 4) a 1-3.5 m-thick red-limonite zone.
Preliminary X-ray fluorescence (XRF), X-ray diffraction (XRD), and mineral liberation analysis (MLA) data show a decrease in Mg and Si and an increase in Fe moving upwards through the laterite profile, corresponding to a transition from silicate- to oxide-rich mineralogy. Oxides and (oxy)-hydroxides comprise goethite, maghemite, hematite, magnetite, chromium spinel, gibbsite/bayerite, and various Mn-minerals, whereas silicates consist of serpentine, chlorite, talc, quartz, pyroxene, olivine, clay minerals, and “garnierite”-like minerals. Ni is hosted by various minerals, which include goethite, Mn-oxides, serpentine, and garnierite, whereas Co is mainly hosted by Mn-oxides and garnierite. It is still unclear in which minerals Sc is primarily hosted.
Mineral chemical analyses (EPMA) are planned to further understand critical metal variability and distribution within the host minerals and throughout the deposits. The first results will be presented here. Our ultimate goal is to characterize and quantify the distribution of Ni, Co and Sc in order to develop more efficient beneficiation processes.

  • Poster
    SEG 2023 Conference: Resourcing the Green Transition, 26.-29.08.2023, London, UK

Permalink: https://www.hzdr.de/publications/Publ-38062
Publ.-Id: 38062


The MALA package - Transferable and Scalable Electronic Structure Simulations Powered by Machine Learning

Fiedler, L.; Cangi, A.

Interactions between electrons and nuclei, the principal building blocks of matter, determine all materials properties. Understanding and modeling these interactions therefore is of paramount importance to pressing scientific questions, e.g., in the context of renewable energy solutions or sustainable materials. However, electronic structure simulations often face a trade-off between accuracy and system size . One may simulate materials at quantum-accuracy, but can only do so for a few thousand atoms, even with the most advanced electronic structure tools, such as density functional theory (DFT). Conversely, large-scale simulations suffer from drastically reduced predictive power due to necessary approximations.

The Materials Learning Algorithms (MALA) package tackles this challenge by combining neural networks, physically constrained optimization algorithms, and efficient post-processing routines to construct machine-learning models of DFT (ML-DFT). Unlike existing ML approaches, MALA creates ML-DFT models that completely replace DFT, providing access to both scalar quantities like energies and volumetric information about the electronic structure, such as the electronic density. We have demonstrated that MALA can be used with any number of atoms (successfully tested with 100’000 atoms), covering a wide range of temperatures and pressures. MALA enables a promising approach for materials modeling at unattained scale and accuracy.

Keywords: Density Functional Theory; Machine Learning; Surrogate Model

  • Invited lecture (Conferences)
    2023 HZDR Science Conference, 16.11.2023, Dresden, Görlitz

Permalink: https://www.hzdr.de/publications/Publ-38061
Publ.-Id: 38061


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