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41421 Publications

OpenFOAM hybrid - A Morphology Adaptive Multifield Two-fluid Model

Schlegel, F.; Meller, R.; Krull, B.; Lehnigk, R.; Tekavcic, M.

The simulation of industrial multiphase flows is challenging, because these flows are typically characterized by coexisting morphologies. Modern simulation methods are well established for dispersed (e.g., Euler-Euler) or resolved (e.g., Volume-of-Fluid) interfacial structures. We propose a morphology adaptive multifield two-fluid model, which is able to handle dispersed and resolved interfacial structures coexisting in the computational domain with the same set of equations. The interfacial drag formulation of Štrubelj and Tiselj (Int J Numer Methods Eng, 2011, Vol. 85, 575-590) is used to describe large interfacial structures in a volume-of-fluid-like manner. For the dispersed structures, the HZDR baseline model is applied. The functionality of the framework is demonstrated by investigating a gas bubble, rising in a liquid, which is laden with micro gas bubbles, a 2D stagnant stratification of water and oil, sharing a large-scale interface, which is penetrated by micro gas bubbles, and an isothermal counter-current stratified flow case. For the latter the framework symmetric and asymmetric turbulence damping is used to account for turbulent flow conditions near an interface. Recent developments focus on the transition region, where bubbles are either over- or under-resolved for Euler-Euler or Volume-of-Fluid (Fig. 1). A drag model to allow tangential slip at an interface and a filtering technique are proposed for stable and robust handling interfacial structures in the transition region. Furthermore, a concept is presented for the transition of oversized dispersed bubbles into the resolved phase.

Keywords: Multiphase Flow; Numerical Simulation; Euler-Euler; OpenFOAM; Hybrid Model

Related publications

  • Lecture (Conference) (Online presentation)
    19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH 19), 06.-11.03.2022, Brüssel, Belgien
  • Contribution to proceedings
    19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19), 06.-11.03.2022, Brüssel, Belgien
    Proceedings of the 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics
  • Open Access Logo Nuclear Science and Engineering 197(2022)10, 2620-2633
    Online First (2022) DOI: 10.1080/00295639.2022.2120316
    Cited 1 times in Scopus

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Permalink: https://www.hzdr.de/publications/Publ-32308
Publ.-Id: 32308


U(VI) and Eu(III) bioassociation behavior and uptake mechanisms of plant cells

Jessat, J.; Moll, H.; Bilke, M.-L.; John, W.; Hübner, R.; Steudtner, R.; Drobot, B.; Bok, F.; Stumpf, T.; Sachs, S.

For a safety assessment of nuclear waste repositories, it is necessary to consider accident scenarios through which radionuclides (RN) can enter the biosphere up to the food chain via groundwater and soil. It is necessary to generate detailed knowledge about the uptake pathways and the interaction of RN with plants to contribute to the molecular process understanding required for a reliable biogeochemical modeling. We investigated the uptake and immobilization (bioassociation) of U(VI) and Eu(III) as a non-radioactive analogue for trivalent actinides by two typical crop plant cell cultures as model systems: canola (Brassica napus) and carrot (Daucus carota). For both metals a time- and concentration-dependent bioassociation behavior was observed, which shows differences between the two plant cell types. U(VI) and Eu(III) were used as luminescence probes to explore their speciation in the two systems. Therefore, time-resolved laser-induced fluorescence spectroscopy (TRLFS) was performed under cryogenic conditions. For an investigation of possible uptake pathways of the metals, it must be considered that both U and Eu are non-essential heavy metals for plants. Therefore, it can be assumed that they have no specific uptake pathway into the plant cells. Possible uptake routes are the use of transport systems of essential micronutrients, whose homeostasis can be disturbed by U(VI) and Eu(III), but uptake via endocytosis and mechanosensitive ion channels is also possible. Experiments were performed to investigate whether the metals can be unspecifically taken up into the cells by blocking Ca(II) ion channels with GdCl3. The investigations are supplemented by transmission electron microscopy combined with energy-dispersive X-ray spectroscopy (TEM with EDX mapping), which contribute to an improved understanding of the processes taking place by localizing the metals in the plant cell.

Keywords: plant cells; radionuclides; uptake mechanisms

  • Lecture (Conference) (Online presentation)
    Goldschmidt 2021, 04.-09.07.2021, Lyon, France

Permalink: https://www.hzdr.de/publications/Publ-32307
Publ.-Id: 32307


Euler-Euler modelling of bubbly flow using particle-center-averaging method

Lyu, H.; Schlegel, F.; Rzehak, R.; Lucas, D.

The standard Euler-Euler two-fluid modelling is based on the phase averaging method and the bubble forces are functions of the gas volume fraction. Therefore, it is not guaranteed that all the gas belonging to the same bubble experiences the same force and moves with the same velocity. However, closure models for interfacial forces are typically developed based on the assumption that the bubbles’ motion can be represented by their center-of-mass on which the forces act. This inconsistency can lead to a nonphysical gas concentration in the center of a pipe or near its wall if the mesh size is smaller than the bubble diameter. In addition, a mesh independent solution may not exist in such simulations. In the present contribution, a particle-center-averaged method is used to average quantities related to the disperse phase such that the bubble forces act on the bubble centers. A systematic approach for the simulation of bubbly flows using the particle-center-averaged method is developed by combining the HZDR baseline closure models, a diffusion-based method for the field coupling and the Euler-Euler framework using the particle-center-averaged method. A physically motivated model for the wall-contact force is introduced to ensure that the bubble centers cannot come arbitrarily close to the walls. To validate this approach, a comparison is made with experimental data for monodisperse and fixed polydisperse bubbly flows in two different pipes. The results show that the particle-center-averaged method can alleviate the over-prediction of the peaks in the gas volume fraction profiles in the near wall region.

Keywords: Particle-center-averaging method; bubble's number density; diffusion equation; bubble force

  • Contribution to proceedings
    19th International Meeting on Nuclear Reactor Thermal Hydraulics, 06.-11.03.2022, Square Brussels Meeting Centre, Belgium

Permalink: https://www.hzdr.de/publications/Publ-32306
Publ.-Id: 32306


Recovery of nanodiamonds produced by laser-induced shock compression of polystyrene

Schuster, A.; Hartley, N.; Lütgert, B. J.; Voigt, K.; Vorberger, J.; Zhang, M.; Benad, A.; Eychmüller, A.; Klemmed, B.; Gericke, D. O.; Rack, A.; Bagnoud, V.; Blazevic, A.; Brabetz, C.; Eisenbarth, U.; Götte, S.; Reemts, D.; Schumacher, D.; Toimil Molares, M. E.; Tomut, M.; Kraus, D.

Hydrocarbons are highly abundant in icy giant planets like Uranus and Neptune and their interior conditions can be created in the laboratory on a nanosecond timescale by applying the technique of laser-induced shock compression using high energy lasers. Based on this method, nanodiamond formation in a simplified hydrocarbon representative, polystyrene (C₈H₈), was observed via in situ X-ray diffraction (XRD). The goal is to physically recover the nanodiamonds that are ejected at hypervelocities upon shock-break out to un-derstand the underlying hydrocarbon separation mechanism by analysing their shape, size, surface mod-ifications and defects. This work is important for planetary interior modelling and may present an additional route for nanodiamond production.

  • Open Access Logo Contribution to external collection
    in: News and Reports from High Energy Density generated by Heavy Ion and Laser Beams 2019, Darmstadt: GSI, 2020
    DOI: 10.15120/GSI-2020-01321

Permalink: https://www.hzdr.de/publications/Publ-32305
Publ.-Id: 32305


How Hyperspectral Image Unmixing and Denoising Can Boost Each Other

Rasti, B.; Koirala, B.; Scheunders, P.; Ghamisi, P.

Hyperspectral linear unmixing and denoising are highly related hyperspectral image (HSI) analysis tasks. In particular, with the assumption of Gaussian noise, the linear model assumed for the HSI in the case of low-rank denoising is often the same as the one used in HSI unmixing. However, the optimization criterion and the assumptions on the constraints are different. Additionally, noise reduction as a preprocessing step in hyperspectral data analysis is often ignored. The main goal of this paper is to study experimentally the influence of noise on the process of hyperspectral unmixing by: (1) investigating the effect of noise reduction as a preprocessing step on the performance of hyperspectral unmixing; (2) studying the relation between noise and different endmember selection strategies; (3) investigating the performance of HSI unmixing as an HSI denoiser; (4) comparing the denoising performance of spectral unmixing, state-of-the-art HSI denoising techniques, and the combination of both. All experiments are performed on simulated and real datasets.

Keywords: hyperspectral image; unmixing; denoising; linear mixing model; low-rank model; noise reduction; abu

Related publications

Permalink: https://www.hzdr.de/publications/Publ-32304
Publ.-Id: 32304


Feature Extraction for Hyperspectral Imagery: The Evolution From Shallow to Deep: Overview and Toolbox

Rasti, B.; Hong, D.; Hang, R.; Ghamisi, P.; Kang, X.; Chanussot, J.; Benediktsson, J. A.

Hyperspectral images (HSIs) provide detailed spectral information through hundreds of (narrow) spectral channels (also known as dimensionality or bands), which can be used to accurately classify diverse materials of interest. The increased dimensionality of such data makes it possible to significantly improve data information content but provides a challenge to conventional techniques (the so-called curse of dimensionality) for accurate analysis of HSIs.

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Permalink: https://www.hzdr.de/publications/Publ-32303
Publ.-Id: 32303


Direct observation of shock‐induced disordering of enstatite below the melting temperature

Hernandez, J.-A.; Morard, G.; Guarguaglini, M.; Alonso-Mori, R.; Benuzzi-Mounaix, A.; Bolis, R.; Fiquet, G.; Galtier, E.; Gleason, A. E.; Glenzer, S.; Guyot, F.; Ko, B.; Lee, H. J.; Mao, W. L.; Nagler, B.; Ozaki, N.; Schuster, A.; Shim, S. H.; Vinci, T.; Ravasio, A.

We report in situ structural measurements of shock‐compressed single crystal orthoenstatite up to 337 ± 55 GPa on the Hugoniot, obtained by coupling ultrafast X‐ray diffraction to laser‐driven shock compression. Shock compression induces a disordering of the crystalline structure evidenced by the appearance of a diffuse X‐ray diffraction signal at nanosecond timescales at 80 ± 13 GPa on the Hugoniot, well below the equilibrium melting pressure (>170 GPa). The formation of bridgmanite and post‐perovskite have been indirectly reported in microsecond‐scale plate‐impact experiments. Therefore, we interpret the high‐pressure disordered state we observed at nanosecond scale as an intermediate structure from which bridgmanite and post‐perovskite crystallize at longer timescales. This evidence of a disordered structure of MgSiO₃ on the Hugoniot indicates that the degree of polymerization of silicates is a key parameter to constrain the actual thermodynamics of shocks in natural environments.

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Permalink: https://www.hzdr.de/publications/Publ-32302
Publ.-Id: 32302


Comparing the optical properties and thermal stability of green (TbPO4), yellow (DyPO4), and red (PrPO4) emitting single crystal samples

Sharma, S.; Beyer, J.; Gloaguen, R.; Heitmann, J.

Blue, green and red-emitting phosphors for near-UV/blue based phosphor blend converted white-light emitting devices have been investigated extensively over the past years. Herein, we present our results on the optical spectroscopy of single crystal samples of TbPO4, DyPO4 and PrPO4 exhibiting prominent emission at green (545 nm), yellow (574 nm) and red (616 nm) region of the electromagnetic spectrum, respectively. We study the temperature dependence of their emission spectra for excitations at 365 and 455 nm, to mimic experimental conditions for phosphor converted light emitting diodes, to show that their thermal quenching temperature is 730 K for TbPO4 (excitation 365 nm), 490 and 520 K for DyPO4 (excitation at 365 and 455 nm), and 540 K for PrPO4 (excitation 455 nm). The TbPO4 emission does not show any considerable blue/red shift at elevated temperatures, while DyPO4 emission is observed close to the center of CIE coordinate diagram. The PrPO4 sample possesses high color purity which shows slight yellow-shift at elevated temperatures. The ground state of Pr3+ and Tb3+ are found to be within the band gap suggesting that both are able to trap holes from the valence band as evinced from the thermoluminescence glow curve data which shows peak maxima at 422 and 437 K due to hole release from the Pr4+ and Tb4+, respectively. The result suggests that the samples have large potential for solid state lighting devices upon choice of an appropriate excitation wavelength.

Permalink: https://www.hzdr.de/publications/Publ-32301
Publ.-Id: 32301


Library of UV-Visible Absorption Spectra of Rare Earth Orthophosphates, LnPO4 (Ln = La-Lu, except Pm)

Sharma, S. K.; Behm, T.; Köhler, T.; Beyer, J.; Gloaguen, R.; Heitmann, J.

In recent times, rare earth orthophosphates ( Ln PO 4 ) have shown great potential as efficient optical materials. They possess either monazite or xenotime –type structures. These light or heavy rare earth bearing orthophosphates also exhibit an extraordinary stability over geological time scale in nature, ∼10 9 years. In the present contribution, we measure, collect, and present a library of absorption spectra of all the Ln PO 4 hosts ( Ln = La–Lu, except Pm) using their single crystal samples, to conclude that the observed spectral features for wavelengths longer than 200 nm were attributable to either Ln- or defect related centers, which corroborate the fact that they have a bandgap higher than 8.0 eV. The absorption band around wavelength, 275 nm, corresponds to defect absorption related to PO 3 centers and/or oxygen vacancies. The hosts can potentially be used to study and interpret unperturbed rare earth emissions due to absence of host related absorption above 300 nm. The information presented herein is expected to serve as a library of absorption spectra for geologists, physicists, material scientists, and chemists working in the field of rare earths.

Keywords: orthophosphate; lanthanide; monazite/xenotime-structure; absorption spectra

Permalink: https://www.hzdr.de/publications/Publ-32300
Publ.-Id: 32300


Development of Sustainable Test Sites for Mineral Exploration and Knowledge Spillover for Industry

Kesselring, M.; Wagner, F.; Kirsch, M.; Ajjabou, L.; Gloaguen, R.

In mineral exploration, pressure is growing to develop innovative technologies and methods with a lower impact on the social and physical environment. To assess the performance and impact of these technologies and methods, test sites are required. Embedded in the literature on sustainable development, this paper explores how social and environmental measures can be implemented in the design of test sites and what industry stake can learn from sustainable test sites. Through qualitative research, two value networks were developed, one for a sustainable test site approach and another for the existing business practice in mineral exploration. Respondents include public sector officials as well as experts in the social, environmental, business, geoscience, and industry fields. The analysis identifies key drivers for the development of socially and environmentally accepted test sites, thus drawing up actionable points for the mineral exploration industry to increase sustainability. The findings of this paper suggest that the integration of experts and partners from social, as well as environmental, sciences drives sustainability at test sites. For industry application, this results in the need to adapt the activities performed, align resource use with sustainability indicators, and also reconfigure the network of partners towards more socially and environmentally oriented business practices.

Keywords: mineral exploration; sustainable development; test sites

Permalink: https://www.hzdr.de/publications/Publ-32299
Publ.-Id: 32299


Large-Scale Neural Solvers for Partial Differential Equations

Stiller, P.; Bethke, F.; Böhme, M.; Pausch, R.; Debus, A.; Torge, S.; Vorberger, J.; Bussmann, M.; Hoffmann, N.

Solving partial differential equations (PDE) is an indispensable part of many branches of science as many processes can be modelled in terms of PDEs. However, recent numerical solvers require manual discretization of the underlying equation as well as sophisticated, tailored code for distributed computing. Scanning the parameters of the underlying model significantly increases the runtime as the simulations have to be cold-started for each parameter configuration. Machine Learning based surrogate models denote promising ways for learning complex relationship among input, parameter and solution. However, recent generative neural networks require lots of training data, i.e. full simulation runs making them costly. In contrast, we examine the applicability of continuous, mesh-free neural solvers for partial differential equations, physics-informed neural networks (PINNs) solely requiring initial/boundary values and validation points for training but no simulation data. The induced curse of dimensionality is approached by learning a domain decomposition that steers the number of neurons per unit volume and significantly improves runtime. Distributed training on large-scale cluster systems also promises great utilization of large quantities of GPUs which we assess by a comprehensive evaluation study. Finally, we discuss the accuracy of GatedPINN with respect to analytical solutions- as well as state-of-the-art numerical solvers, such as spectral solvers.

Keywords: PDE solving; Physics-informed Neural Networks; Machine Learning; HPC

  • Contribution to proceedings
    SMC 2020: Driving Scientific and Engineering Discoveries Through the Convergence of HPC, Big Data and AI pp, 26.-28.08.2020, Virtual Conference, Virtual Conference
    Driving Scientific and Engineering Discoveries Through the Convergence of HPC, Big Data and AI: Springer Nature Switzerland AG 2020, 978-3-030-63393-6
    DOI: 10.1007/978-3-030-63393-6

Permalink: https://www.hzdr.de/publications/Publ-32298
Publ.-Id: 32298


Structural Similarity Based Anatomical and Functional Brain Imaging Fusion

Kumar, N.; Hoffmann, N.; Oelschlägel, M.; Koch, E.; Kirsch, M.; Gumhold, S.

Multimodal medical image fusion helps in combining contrasting features from two or more input imaging modalities to represent fused information in a single image. One of the pivotal clinical applications of medical image fusion is the merging of anatomical and functional modalities for fast diagnosis of malign tissues. In this paper, we present a novel end-to-end unsupervised learning based Convolutional neural network (CNN) for fusing the high and low frequency components of MRI-PET grayscale image pairs publicly available at ADNI by exploiting Structural Similarity Index (SSIM) as the loss function during training. We then apply color coding for the visualization of the fused image by quantifying the contribution of each input image in terms of the partial derivatives of the fused image. We find that our fusion and visualization approach results in better visual perception of the fused image, while also comparing favorably to previous methods when applying various quantitative assessment metrics.

Keywords: Medical image fusion; MRI-PET; Convolutional neural networks (CNN); Structural similarity index (SSIM)

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Permalink: https://www.hzdr.de/publications/Publ-32297
Publ.-Id: 32297


FuseVis: Interpreting Neural Networks for Image Fusion Using Per-Pixel Saliency Visualization

Kumar, Nishant; Gumhold, Stefan

Image fusion helps in merging two or more images to construct a more informative single fused image. Recently, unsupervised learning-based convolutional neural networks (CNN) have been used for different types of image-fusion tasks such as medical image fusion, infrared-visible image fusion for autonomous driving as well as multi-focus and multi-exposure image fusion for satellite imagery. However, it is challenging to analyze the reliability of these CNNs for the image-fusion tasks since no groundtruth is available. This led to the use of a wide variety of model architectures and optimization functions yielding quite different fusion results. Additionally, due to the highly opaque nature of such neural networks, it is difficult to explain the internal mechanics behind its fusion results. To overcome these challenges, we present a novel real-time visualization tool, named FuseVis, with which the end-user can compute per-pixel saliency maps that examine the influence of the input image pixels on each pixel of the fused image. We trained several image fusion-based CNNs on medical image pairs and then using our FuseVis tool we performed case studies on a specific clinical application by interpreting the saliency maps from each of the fusion methods. We specifically visualized the relative influence of each input image on the predictions of the fused image and showed that some of the evaluated image-fusion methods are better suited for the specific clinical application. To the best of our knowledge, currently, there is no approach for visual analysis of neural networks for image fusion. Therefore, this work opens a new research direction to improve the interpretability of deep fusion networks. The FuseVis tool can also be adapted in other deep neural network-based image processing applications to make them interpretable

Keywords: image fusion; convolutional neural networks (CNN); saliency visualization; jacobians; graphical use interface (GUI)

Permalink: https://www.hzdr.de/publications/Publ-32296
Publ.-Id: 32296


Deep white matter analysis (DeepWMA): Fast and consistent tractography segmentation

Zhang, F.; Karayumak, S. C.; Hoffmann, N.; Rathi, Y.; Golby, A. J.; O’Donnell, L. J.

White matter tract segmentation, i.e. identifying tractography fibers (streamline trajectories) belonging to anatomically meaningful fiber tracts, is an essential step to enable tract quantification and visualization. In this study, we present a deep learning tractography segmentation method (DeepWMA) that allows fast and consistent identification of 54 major deep white matter fiber tracts from the whole brain. We create a large-scale training tractography dataset of 1 million labeled fiber samples, and we propose a novel 2D multi-channel feature descriptor (FiberMap) that encodes spatial coordinates of points along each fiber. We learn a convolutional neural network (CNN) fiber classification model based on FiberMap and obtain a high fiber classification accuracy of 90.99% on the training tractography data with ground truth fiber labels. Then, the method is evaluated on a test dataset of 597 diffusion MRI scans from six independently acquired populations across genders, the lifespan (1 day - 82 years), and different health conditions (healthy control, neuropsychiatric disorders, and brain tumor patients). We perform comparisons with two state-of-the-art tract segmentation methods. Experimental results show that our method obtains a highly consistent tract segmentation result, where on average over 99% of the fiber tracts are successfully identified across all subjects under study, most importantly, including neonates and patients with space-occupying brain tumors. We also demonstrate good generalization of the method to tractography data from multiple different fiber tracking methods. The proposed method leverages deep learning techniques and provides a fast and efficient tool for brain white matter segmentation in large diffusion MRI tractography datasets.

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Permalink: https://www.hzdr.de/publications/Publ-32295
Publ.-Id: 32295


Visualisation of Medical Image Fusion and Translation for Accurate Diagnosis of High Grade Gliomas

Kumar, N.; Hoffmann, N.; Kirsch, M.; Gumhold, S.

The medical image fusion combines two or more modalities into a single view while medical image translation synthesizes new images and assists in data augmentation. Together, these methods help in faster diagnosis of high grade malignant gliomas. However, they might be untrustworthy due to which neurosurgeons demand a robust visualisation tool to verify the reliability of the fusion and translation results before they make pre-operative surgical decisions. In this paper, we propose a novel approach to compute a confidence heat map between the source-target image pair by estimating the information transfer from the source to the target image using the joint probability distribution of the two images. We evaluate several fusion and translation methods using our visualisation procedure and showcase its robustness in enabling neurosurgeons to make finer clinical decisions.

Keywords: Visualisation; Medical Image Fusion; Medical Image Translation; Mutual information

Permalink: https://www.hzdr.de/publications/Publ-32294
Publ.-Id: 32294


Review and new concepts for neutron-capture measurements of astrophysical interest

Domingo-Pardo, C.; Babiano-Suarez, V.; Balibrea-Correa, J.; Caballero, L.; Ladarescu, I.; Lerendegui-Marco, J.; Tain, J. L.; Calviño, F.; Casanovas, A.; Segarra, A.; Tarifeño-Saldivia, A. E.; Guerrero, C.; Millán-Callado, M. A.; Quesada, J. M.; Rodríguez-González, M. T.; Aberle, O.; Alcayne, V.; Amaducci, S.; Andrzejewski, J.; Audouin, L.; Bacak, M.; Barbagallo, M.; Bennett, S.; Berthoumieux, E.; Bosnar, D.; Brown, A. S.; Busso, M.; Caamaño, M.; Calviani, M.; Cano-Ott, D.; Cerutti, F.; Chiaveri, E.; Colonna, N.; Cortés, G. P.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Damone, L. A.; Davies, P. J.; Diakaki, M.; Dietz, M.; Dressler, R.; Ducasse, Q.; Dupont, E.; Durán, I.; Eleme, Z.; Fernández-Domíngez, B.; Ferrari, A.; Ferro-Gonçalves, I.; Finocchiaro, P.; Furman, V.; Garg, R.; Gawlik, A.; Gilardoni, S.; Göbel, K.; González-Romero, E.; Gunsing, F.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Jiri, U.; Junghans, A.; Kadi, Y.; Käppeler, F.; Kimura, A.; Knapová, I.; Kokkoris, M.; Kopatch, Y.; Krticka, M.; Kurtulgil, D.; Lederer-Woods, C.; Lonsdale, S.-J.; Macina, D.; Manna, A.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Maugeri, E.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Mingrone, F.; Moreno-Soto, J.; Musumarra, A.; Negret, A.; Ogállar, F.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Petrone, C.; Piersanti, L.; Pirovano, E.; Porras, I.; Praena, J.; Ramos Doval, D.; Reifarth, R.; Rochman, D.; Rubbia, C.; Sabaté-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Schumann, D.; Sekhar, A.; Smith, A. G.; Sosnin, N.; Sprung, P.; Stamatopoulos, A.; Tagliente, G.; Tassan-Got, L.; Thomas, B.; Torres-Sánchez, P.; Tsinganis, A.; Urlass, S.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P. J.; Wright, T. J.; Žugec, P.; The, N. T. C.

The idea of slow-neutron capture nucleosynthesis formulated in 1957 triggered a tremendous experimental effort in different laboratories worldwide to measure the relevant nuclear physics input quantities, namely (n, γ) cross sections over the stellar temperature range (from few eV up to several hundred keV) for most of the isotopes involved from Fe up to Bi. A brief historical review focused on total energy detectors will be presented to illustrate how advances in instrumentation have led to the assessment of new aspects of s-process nucleosynthesis and to the progressive refinement of stellar models. A summary will be presented on current efforts to develop new detection concepts, such as the Total-Energy Detector with γ-ray imaging capability (i-TED). The latter is based on the simultaneous combination of Compton imaging with neutron time-of-flight (TOF) techniques, in order to achieve a superior level of sensitivity and selectivity in the measurement of stellar neutron capture rates.

Permalink: https://www.hzdr.de/publications/Publ-32293
Publ.-Id: 32293


Neutron capture measurement at the n TOF facility of the 204Tl and 205Tl s-process branching points

Casanovas, A.; Tarifeño-Saldivia, A. E.; Domingo-Pardo, C.; Calviño, F.; Maugeri, E.; Guerrero, C.; Lerendegui-Marco, J.; Dressler, R.; Heinitz, S.; Schumann, D.; Tain, J. L.; Quesada, J. M.; Aberle, O.; Alcayne, V.; Amaducci, S.; Andrzejewski, J.; Audouin, L.; Babiano-Suarez, V.; Bacak, M.; Balibrea, J.; Barbagallo, M.; Bennett, S.; Berthoumieux, E.; Bosnar, D.; Brown, A. S.; Busso, M.; Caamaño, M.; Caballero, L.; Calviani, M.; Cano-Ott, D.; Cerutti, F.; Chiaveri, E.; Colonna, N.; Cortés, G. P.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Damone, L. A.; Davies, P. J.; Diakaki, M.; Dietz, M.; Ducasse, Q.; Dupont, E.; Durán, I.; Eleme, Z.; Fernández-Domíngez, B.; Ferrari, A.; Ferro-Gonçalves, I.; Finocchiaro, P.; Furman, V.; Garg, R.; Gawlik, A.; Gilardoni, S.; Göbel, K.; González-Romero, E.; Gunsing, F.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Jiri, U.; Junghans, A.; Kadi, Y.; Käppeler, F.; Kimura, A.; Knapová, I.; Kokkoris, M.; Kopatch, Y.; Krticka, M.; Kurtulgil, D.; Ladarescu, I.; Lederer-Woods, C.; J. Lonsdale, S.; Macina, D.; Manna, A.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Millán-Callado, M. A.; Mingrone, F.; Moreno-Soto, J.; Musumarra, A.; Negret, A.; Ogállar, F.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Petrone, C.; Piersanti, L.; Pirovano, E.; Porras, I.; Praena, J.; Doval, D. R.; Reifarth, R.; Rochman, D.; Rubbia, C.; Sabaté-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Sekhar, A.; Smith, A. G.; Sosnin, N.; Sprung, P.; Stamatopoulos, A.; Tagliente, G.; Tassan-Got, L.; Thomas, B.; Torres-Sánchez, P.; Tsinganis, A.; Urlass, S.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P. J.; Wright, T. J.; Žugec, P.; Koester, U.

Neutron capture cross sections are one of the fundamental nuclear data in the study of the s (slow) process of nucleosynthesis. More interestingly, the competition between the capture and the decay rates in some unstable nuclei determines the local isotopic abundance pattern. Since decay rates are often sensible to temperature and electron density, the study of the nuclear properties of these nuclei can provide valuable constraints to the physical magnitudes of the nucleosynthesis stellar environment. Here we report on the capture cross section measurement of two thallium isotopes, 204Tl and 205Tl performed by the time-of-flight technique at the n TOF facility at CERN. At some particular stellar s-process environments, the decay of both nuclei is strongly enhanced, and determines decisively the abundance of two s-only isotopes of lead, 204Pb and 205Pb. The latter, as a long-lived radioactive nucleus, has potential use as a chronometer of the last s-process events that contributed to final solar isotopic abundances.

Permalink: https://www.hzdr.de/publications/Publ-32292
Publ.-Id: 32292


Neutron Capture Cross Section for 10Be

Volknandt, M.; Eberhardt, K.; Endres, A.; Erbacher, P.; Fix, M.; Göbel, K.; Heftrich, T.; Heinitz, S.; Hrivula, E.; Junghans, A.; Käppeler, F.; Kivel, N.; Langer, C.; Mengoni, A.; Reifarth, R.; Schmidt, S.; Schumann, D.; Thomas, B.; Veltum, D.; Weigand, M.; Wiehl, N.; Wolf, C.

The determination of the involved reaction cross sections is essential for the understanding of how the big bang nucleosynthesis and nuclear reactions in stars contribute to the observed abundances. One of those, which has not been measured so far, is the 10Be(n,γ) cross section.

A 10BeO sample, provided by PSI Villigen, was irradiated in a cyclic activation at the TRIGA reactor in Mainz. The characteristic γ-rays following the decay of 11Be were measured using LaBr3 scintillation detectors. The thermal neutron cross section and the resonance integral were experimentally determined for the first time.

Permalink: https://www.hzdr.de/publications/Publ-32291
Publ.-Id: 32291


80Se(n,γ) cross-section measurement at CERN n_TOF

Babiano-Suarez, V.; Aberle, O.; Alcayne, V.; Amaducci, S.; Andrzejewski, J.; Audouin, L.; Bacak, M.; Balibrea-Correa, J.; Barbagallo, M.; Bennett, S.; Berthoumieux, E.; Bosnar, D.; Brown, A. S.; Busso, M.; Caamaño, M.; Caballero, L.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Casanovas, A.; Cerutti, F.; Chiaveri, E.; Colonna, N.; Cortés, G. P.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Damone, L. A.; Davies, P. J.; Diakaki, M.; Dietz, M.; Domingo-Pardo, C.; Dressler, R.; Ducasse, Q.; Dupont, E.; Durán, I.; Eleme, Z.; Fernández-Domíngez, B.; Ferrari, A.; Ferro-Gonçalves, I.; Finocchiaro, P.; Furman, V.; Garg, R.; Gawlik, A.; Gilardoni, S.; Göbel, K.; González-Romero, E.; Guerrero, C.; Gunsing, F.; Heinitz, S.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Jiri, U.; Junghans, A.; Kadi, Y.; Käppeler, F.; Kimura, A.; Knapová, I.; Kokkoris, M.; Kopatch, Y.; Krticka, M.; Kurtulgil, D.; Ladarescu, I.; Lederer-Woods, C.; Lerendegui-Marco, J.; Lonsdale, S.-J.; Macina, D.; Manna, A.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Maugeri, E.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Millán-Callado, M. A.; Mingrone, F.; Moreno-Soto, J.; Musumarra, A.; Negret, A.; Ogállar, F.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Petrone, C.; Piersanti, L.; Pirovano, E.; Porras, I.; Praena, J.; Quesada, J. M.; Ramos Doval, D.; Reifarth, R.; Rochman, D.; Rubbia, C.; Sabaté-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Schumann, D.; Sekhar, A.; Smith, A. G.; Sosnin, N.; Sprung, P.; Stamatopoulos, A.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A. E.; Tassan-Got, L.; Thomas, B.; Torres-Sánchez, P.; Tsinganis, A.; Urlass, S.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P. J.; Wright, T. J.; Žugec, P.

Radiative neutron capture cross section measurements are of fundamental importance for the study of the slow neutron capture (s-) process of nucleosynthesis. This mechanism is responsible for the formation of most elements heavier than iron in the Universe. Particularly relevant are branching nuclei along the s-process path, which are sensitive to the physical conditions of the stellar environment. One such example is the branching at 79Se (3.27 × 105 y), which shows a thermally dependent β-decay rate. However, an astrophysically consistent interpretation requires also the knowledge of the closest neighbour isotopes involved. In particular, the 80Se(n,γ) cross section directly affects the stellar yield of the "cold" branch leading to the formation of the s-only 82Kr. Experimentally, there exists only one previous measurement on 80Se using the time of flight (TOF) technique. However, the latter suffers from some limitations that are described in this presentation. These drawbacks have been significantly improved in a recent measurement at CERN n TOF. This contribution presents a summary of the latter measurement and the status of the data analysis.

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Permalink: https://www.hzdr.de/publications/Publ-32290
Publ.-Id: 32290


Radiotherapy enhances uptake and efficacy of 90Y-cetuximab: A preclinical trial

Dietrich, A.; Andreeff, M.; Koi, L.; Bergmann, R.; Schubert, M.; Schreiner, L.; Löck, S.; Sihver, W.; Freudenberg, R.; Hering, S.; Pietzsch, H.-J.; Steinbach, J.; Kotzerke, J.; Baumann, M.; Krause, M.

Background and purpose

Systemic molecular radiotherapy utilizes internal irradiation by radionuclide-labeled tumor-targeting agents with the potential to destroy (micro-)metastases. However, doses that are applicable in solid tumors do not reach the levels nessecary for tumor control. Thus, the combination of molecular and external radiotherapy is a promising treatment strategy, as enhanced tumor doses can be delivered with and without minor overlapping toxicities. Here, we combined a 90Y-labeled anti-EGFR antibody (Cetuximab) with clinically relevant fractionated radiotherapy in a preclinical trial using head and neck squamous cell carcinoma xenograft tumors.
Materials and methods

To model 90Y-Cetuximab uptake for treatment schedule optimization, FaDu-bearing mice were injected with near-infrared-labeled-Cetuximab at different time points during radiotherapy with differing doses. Cetuximab uptake was longitudinally followed by in vivo-optical imaging. Tumor control probability experiments with fractionated radiotherapy (30 fx, 6 weeks, 8 dose groups/ arm) in combination with 90Y-Cetuximab were performed to test the curative potential.

Results

Imaging of near-infrared-labeled-Cetuximab uptake revealed that low to moderate external beam doses can enhance antibody uptake. Using the optimized schedule, combination of molecular and external radiotherapy using 90Y-Cetuximab at a dose that did not result in permanent tumor inactivation in previous experiments, led to substantially increased tumor control compared to radiotherapy alone.
Conclusion

Our results indicate that combination of radiolabeled therapeutics with clinically relevant fractionated radiotherapy has a remarkable potential to improve curative treatment outcome. Application of some radiation dose prior to injection may improve drug uptake and enable patient stratification and treatment personalization via a corresponding PET-tracer during therapy.

Keywords: Molecular radiotherapy Combination therapy Cetuximab Preclinical imaging Radiation therapy Radioimmu

Permalink: https://www.hzdr.de/publications/Publ-32289
Publ.-Id: 32289


On-shot dosimetry setup for radiobiology studies on volumetric in-vivo samples with laser accelerated proton beams

Reimold, M.

Laser plasma-based accelerators promise to provide proton sources for radiobiological studies with extended possibilities compared to conventional accelerators due to short acceleration lengths, high pulse doses, high dose rates and the usage of compact magnets for beam guiding operated in pulsed mode. For the generation of radiobiological relevant proton energies, Petawatt (PW) class laser powers are required, which can be provided at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) by the DRACO laser system and the upcoming PENELOPE laser system. Both laser systems will be used to perform radiobiological in-vivo studies which require precise absolute dosimetry for three-dimensional depth-dose profiles on a millimeter scale. This presentation gives an overview of the dosimetry setup developed for radio-biological studies on volumetric samples consisting of a combination of several different detector types for on-shot dose measurement (ionization chambers, time-of-flight spectrometer), absolute calibration (radiochromic films) and spatial dose profile optimization (scintillators). Additionally, a recently developed detector system design based on scintillator emission tomography for the full reconstruction of an arbitrary proton depth profile generated by a single proton bunch will be presented. Details on the reconstruction of the 3D dose distribution inside the scintillator volume and the reverse calculation of the angularly resolved proton energy spectrum are discussed.

Related publications

  • Lecture (Conference) (Online presentation)
    LaPlaSS, 18.09.2020, Salamanca/ Dresden, Spanien/ Deutschland
  • Lecture (Conference) (Online presentation)
    BLIN4, 29.06.2020, München/ Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32288
Publ.-Id: 32288


Beam monitoring and dosimetry for in vivo studies with laser-driven protons at Draco PW

Reimold, M.

Petawatt laser-plasma based proton sources, capable of providing multi-10 MeV proton pulses at ultra-high dose rates of 10^9 Gy/s, are unique sources for radiobiological studies of ~mm size 3D in vivo samples in the recently strongly investigated FLASH regime.
At Draco PW (HZDR), a compact and tunable pulsed power beamline is utilized for efficient beam transport and spectral filtering for dose deposition in a sample. The setup was successfully used for in vivo radiobiological studies with up to 20 Gy single shot doses as well as for accumulative multi-shot low dose (~500 mGy) schemes for %-level accuracy of dose delivery.
Regarding beam monitoring and dosimetry, the inherent fluctuations of the laser-driven source, the ultra-high dose rate and the experimental environment (pulsed power, EMP) pose challenges for established dosimetry methods.
In this presentation, we present a non-invasive scintillator-based time-of-flight spectrometer as a unique tool for single-shot online beam optimization and monitoring of laser-driven proton pulses in application experiments. Calibration of the device against established dosimeters (here radiochromic film) in combination with Monto Carlo simulations additionally allows dosimetric use, overcoming saturation issues with dose rate or linear energy transfer present in other devices.
To illustrate the suitability of the time-of-flight spectrometer as a beam monitor and absolute dosimeter for laser-based protons, the time-of-flight data of two radiobiological in vivo irradiation campaigns performed at the implemented beamline at the DRACO PW facility are presented.

Keywords: time-of-flight spectrometer

Related publications

  • Lecture (Conference) (Online presentation)
    WHELMI-Meeting, 17.-18.12.2020, Dresden-Rossendorf/ Rechovot, Deutschland/ Israel
  • Lecture (Conference) (Online presentation)
    Gruppenseminar, 08.02.2021, Dresden, Deutschland
  • Lecture (Conference) (Online presentation)
    M&T Student Retreat, 01.02.2021, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32287
Publ.-Id: 32287


Nanoparticle-Stabilized Perforated Lamellar Morphology in Block Copolymer/Quantum Dot Hybrids

Singh, S.; Horechyy, A.; Yadav, S.; Formanek, P.; Hübner, R.; Srivastava, R. K.; Sapra, S.; Fery, A.; Nandan, B.

We report on the surprising observation of a unique perforated lamellar (PL) morphology in a mixture of an asymmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer and CdSe−CdS quantum dots (QDs). The PL morphology formed by the PS-b-P4VP/CdSe−CdS composites consisted of alternating layers of PS and P4VP, where the layer formed by the minority PS block contained cylindrical perforations of the majority P4VP block. Most interestingly, the CdSe−CdS QDs were localized exclusively in the P4VP perforations. The swelling of the bulk samples in a P4VP selective solvent also allowed the isolation of the perforated PS nanosheets, with QDs localized in the perforations, which further provided strong evidence for the formation of the unique PL morphology. The observed PL morphology was, plausibly, energetically stabilized because of the localization of QDs within the P4VP perforations, which allowed for the conformational entropy minimization of the majority P4VP block. The present work reveals possibilities for the discovery of novel hierarchical structures in block copolymer/nanoparticle composite systems and also provides new opportunities for the application of such materials in nanotechnology.

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Permalink: https://www.hzdr.de/publications/Publ-32286
Publ.-Id: 32286


Assessment of column tray flow patterns and separation efficiencies on large-scale distillation trays

Vishwakarma, V.; Marchini, S.; Abdul Haq, S.; Schleicher, E.; Bieberle, A.; Schubert, M.; Hampel, U.

Thorough characterization of mixing behavior and separation efficiencies of large-scale distillation trays is important especially in their design phase. A precise account of the tray operation would allow modifying their mixing and mass-transfer characteristics (via design modifications) for better separation efficiencies (see design strategy in Fig. 1, left).
Fig. 1. Design strategy for distillation trays (left), and relevant data on the distributions of liquid holdup, residence time, RTD variance, and species concentration (right).
The existing literature lacks a thorough hydrodynamic description of large-scale distillation trays. Thus, the CFD studies have relied either on trivial measurements (such as those of pressure drop, liquid weeping and entrainment, visual froth height, etc.) or the available low-resolution residence time data for model validation rather than on refined data on flow path and local mixing.
Meanwhile, an extensive description of the tray hydrodynamics can be made available using the recently proposed flow profiler.1 Based on recent developments in that regard, the distributions of liquid holdup, residence time and mixing are obtained over the entire deck (see Fig. 1, right) for several gas and liquid loadings at high resolution.
The acquired data permits to predict the tray efficiency by applying models that relate liquid flow patterns with the tray performance, such as the recently proposed ‘Refined RTD (RRTD) model’ that considers the mixing behavior at intermediary tray locations.2
Eventually, experimental data on air stripping of isobutyl acetate from the aqueous solution at tray loadings same as those during the hydrodynamic experiments can be applied to validate the proposed efficiency model. An example of species concentration distribution (i.e., examined using UV spectroscopy) over the tray deck is also shown in Fig. 1 (right).

[1] Vishwakarma, V., Schleicher, E., Schubert, M., Tschofen, M. and Löschau, M., 2020. Sensor zur Vermessung von Strömungsprofilen in großen Kolonnen und Apparaten. Deutsches Patent und Markenamt, DE 10 2018 124 501.
[2] Vishwakarma, V., Schubert, M. and Hampel, U., 2019. Development of a refined RTD-based efficiency prediction model for cross-flow trays. Ind. Eng. Chem. Res., 58(8), pp.3258-3268.

  • Lecture (Conference) (Online presentation)
    Jahrestreffen der ProcessNet-Fachgruppen Fluidverfahrenstechnik und Wärme- und Stoffübertragung, 24.-26.02.2021, Online event, Germany

Permalink: https://www.hzdr.de/publications/Publ-32285
Publ.-Id: 32285


Experimental analysis of the hydrodynamic performance of an industrial-scale cross-flow sieve tray

Vishwakarma, V.; Abdul Haq, S.; Schleicher, E.; Schubert, M.; Hampel, U.

This work reports the hydrodynamic description of a large-scale sieve tray equipped in an air/water column mockup. The test tray accommodates a multi-probe flow profiler for simultaneous conductivity measurements. 3D liquid holdup distribution, liquid residence time distribution and effective froth height distribution are obtained at high spatiotemporal resolution for several gas and liquid loadings. The liquid flow and mixing patterns are visualized via tracer-based experiments. The methodologies used for acquiring these distributions are discussed in this work. Thorough examination of the processed experimental data reveals the hydrodynamic characteristics of an operational sieve tray for the studied loadings.

Keywords: column tray; hydrodynamics; effective froth height; 3D liquid holdup; tracer-response analysis

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Permalink: https://www.hzdr.de/publications/Publ-32284
Publ.-Id: 32284


Transmission ion microscopy and time-of-flight spectroscopy

Mousley, M.; Möller, W.; Philipp, P.; Bouton, O.; Klingner, N.; Serralta Hurtado De Menezes, E.; Hlawacek, G.; Wirtz, T.

A Transmission Ion Microscope (TIM), the Galileo prototype, has been built at the Luxembourg Institute of Science and Technology ( LIST) [1]. This is part of a new interest in the imaging properties of transmitted helium ions [2] [3] [4]. This allows the combination of both helium ions and neutrals to be detected after passing through a sample , or, if post sample deflection is used, then only the signal from the neutrals ( Figure 1 A). The helium ions have an energy between 10 keV and 20 keV and are produced in a Duoplasmatron ion source.
The prototype instrument is very flexible and uses a microchannel plate (MCP) which can be configured in multiple ways to enable analysis modalities, producing datasets of varying dimensionality. 2D images can be obtained either with a phosphor screen and a defocussed beam in direct TIM mode (analogous to transmission electron microscopy) or with an anode plate to collect the total detector signal in scanning mode providing scanning-TIM (STIM) images. By using fast blanking electronics (similar to [5] ), pulses of ions can be used to add time-of-flight (TOF) information (Figure 3), allowing a TOF-STIM mode to collect 3D datasets (x, y, t). Alternatively, a delay line detector (DLD) can be used to provide detector plane images with corresponding TOF values at each detector pixel, to collect TOF-TIM (3D datasets (, x’, y’, t). Finally, detector imaged DLD TOF-STIM can be used, in this mode, for each beam position on the sample, the arrival time and position on the detector is recorded for each count (5D datasets, x, y, x’, y’, t). The prototype TIM is also equipped with a secondary electron (SE) detector providing additional SE intensity for each pixel position in STIM modes (Figure 1 B) .
Example TOF datasets from materials science related samples (e.g. Au on Si) will be presented. In addition to microscopy, the effects of 20 keV helium ion irradiation on Au-Silica core-shell nanoparticles have been evaluated. Using bright field Transmission Electron Microscopy (TEM) imaging of irradiated particles, the effects of irradiation were tracked for increasing fluences [6]. It was seen that satellite particles are formed around the main Au core (Figure 2 , A and B) and neighbouring silica shells fuse together (Figure 2, C and Figure 2D). These effects will determine the suitable doses when imaging nanoparticles with 20 keV helium ions.

[1] M. Mousley et al., “Stationary beam full-field transmission helium ion microscopy using sub-50 keV He+: Projected images and intensity patterns,” Beilstein J. Nanotechnol., vol. 10, pp. 1648–1657, Aug. 2019, doi: 10.3762/bjnano.10.160. [Online]. Available: https://www.beilstein-journals.org/bjnano/articles/10/160
[2] K. L. Kavanagh C. Herrmann and J. A. Notte, “Camera for transmission He + ion microscopy,” J. Vac. Sci. Technol. B, Nanotechnol. Microelectron. Mater. Process. Meas. Phenom., vol. 35, no. 6, p. 06G902, 2017, doi: 10.1116/1.4991898. [Online]. Available: http://avs.scitation.org/doi/10.1116/1.4991898
[3] T. Wirtz O. De Castro J.-N. Audinot and P. Philipp, “Imaging and Analytics on the Helium Ion Microscope,” Annu. Rev. Anal. Chem., vol. 12, no. 1, 2019, doi: 10.1146/annurev-anchem-061318-115457.
[4] E. Serralta et al., “Scanning transmission imaging in the helium ion microscope using a microchannel plate with a delay line detector,” Beilstein J. Nanotechnol., vol. 11, pp. 1854–1864, 2020, doi: 10.3762/BJNANO.11.167.
[5] N. Klingner R. Heller G. Hlawacek S. Facsko and J. von Borany, “Time-of-flight secondary ion mass spectrometry in the helium ion microscope,” Ultramicroscopy, vol. 198, no. March 2019, pp. 10–17, 2019, doi: 10.1016/j.ultramic.2018.12.014. [Online]. Available: https://doi.org/10.1016/j.ultramic.2018.12.014
[6] M. Mousley et al., “Structural and chemical evolution of Au-silica core–shell nanoparticles during 20 keV helium ion irradiation: a comparison between experiment and simulation,” Sci. Rep., vol. 10, no. 1, pp. 1–13, 2020, doi: 10.1038/s41598-020-68955-7. [Online]. Available: https://doi.org/10.1038/s41598-020-68955-7

Related publications

  • Poster
    Microscopy & Microanalysis 2021, 01.-05.08.2021, Pittsburgh, United States of America

Permalink: https://www.hzdr.de/publications/Publ-32283
Publ.-Id: 32283


Nonlinear response in warm dense matter

Vorberger, J.

Talk at Hirschegg workshop "41th International Workshop on High Energy Density Physics with Intense Ion and Laser Beams"

Keywords: warm dense matter; nonlinear response; quantum Monte Carlo; Green's function

  • Lecture (Conference) (Online presentation)
    41th International Workshop on High Energy Density Physics with Intense Ion and Laser Beams, 01.-05.02.2021, Hirschegg, Austria

Permalink: https://www.hzdr.de/publications/Publ-32282
Publ.-Id: 32282


Nonequilibrium in general and in warm dense matter

Vorberger, J.

Talk given at CASUS

Keywords: non-equilibrium; warm dense matter; Boltzmann; kadanoff-baym; two temperature model

  • Lecture (others) (Online presentation)
    MEC Seminar at CASUS, 26.01.2021, Görlitz, Germany

Permalink: https://www.hzdr.de/publications/Publ-32281
Publ.-Id: 32281


The Impact of Barium Isotopes in Radiopharmacy and Nuclear Medicine – from Past to Presence

Reissig, F.; Kopka, K.; Mamat, C.

With the exception of beryllium, every alkaline earth metal is characterized by a calcimimetic behavior. Thus, in vivo biodistribution mostly occurs in form of a massive accumulation in bone tissues, consisting of hydroxyapatite to a major extent. Apart from the lightest elements beryllium and magnesium, animal studies and human studies regarding the overall in vivo behavior were carried out by using radioisotopes of the elements calcium, strontium, barium, and radium. To date, only strontium with its radioisotopes gained importance for applications in nuclear medicine, mainly for pain-reducing and palliative treatment of bone metastases. In contrast, barium isotopes can be useful imaging agents and possible diagnostic analogues for theranostic approaches. This review focuses on the characteristic and chemical behavior of barium compounds, possible radioactive barium isotopes for future applications in nuclear medicine and radiopharmacy as well as recent results regarding barium-131 as diagnostic match for radium isotopes used in targeted alpha therapy.

Keywords: Barium isotopes; bone seeker; alkaline earth metals; brachytherapy

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Permalink: https://www.hzdr.de/publications/Publ-32280
Publ.-Id: 32280


Dependence of the damage in optical metal/dielectric coatings on the energy of ions in irradiation experiments for space qualification

Pelizzo, M. G.; Corso, A. J.; Santi, G.; Hübner, R.; Garoli, D.; Doyle, D.; Lubin, P.; Cohen, A. N.; Erlikhman, J.; Favaro, G.; Bazzan, M.; Drobny, J.; Curreli, D.; Umansky, M.

Terrestrial accelerator facilities can generate ion beams which enable the testing of the resistance of materials and thin film coatings to be used in the space environment. In this work, a TiO2/Al bi-layer coating has been irradiated with a He+ beam at three different energies. The same flux and dose have been used in order to investigate the damage dependence on the energy. The energies were selected to be in the range 4-100 keV, in order to consider those associated to the quiet solar wind and to the particles present in the near-Earth space environment. The optical, morphological and structural modifications have been investigated by using various techniques. Surprisingly, the most damaged sample is the one irradiated at the intermediate energy, which, on the other hand, corresponds to the case in which the interface between the two layers is more stressed. Results demonstrate that ion energies for irradiation tests must be carefully selected to properly qualify space components.

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Permalink: https://www.hzdr.de/publications/Publ-32279
Publ.-Id: 32279


Annual Report 2020 - Institute of Resource Ecology

Stumpf, T.; Foerstendorf, H.; Bok, F.; Richter, A.

The institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden –Rossendorf (HZDR). Our research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Ra-diation Research (NUSAFE)” of the Helmholtz Association (HGF) and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. The program NUSAFE, and therefore all work which is done at IRE, belong to the research field “Energy” of the HGF.

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  • Open Access Logo Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-113 2021
    ISSN: 2191-8708, eISSN: 2191-8716

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Permalink: https://www.hzdr.de/publications/Publ-32278
Publ.-Id: 32278


Data for: Spin-wave dynamics and symmetry breaking in an artificial spin ice

Saha, S.; Zhou, J.; Hofhuis, K.; Kakay, A.; Scagnoli, V.; Heyderman, L. J.; Gliga, S.

These data are related to the https://arxiv.org/abs/2011.04505 publication entitled: Spin-wave dynamics and symmetry breaking in an artificial spin ice

The archive-files.txt contains a detailed description of the files stored in the repository-files-paper.tar file.

The geometry .bmp files are also included, thus anyone can reproduce the results by using mumax3 from https://mumax.github.io

Keywords: nanomagnetism; artificial spin ice; spin wave; magnetization dynamics; magnonic crystal

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Permalink: https://www.hzdr.de/publications/Publ-32277
Publ.-Id: 32277


Sub-20 nm multilayer nanopillar patterning for hybrid SET/CMOS integration: Figs. 1a, 1b and 5

Engelmann, H.-J.
Project Leader: von Borany, Johannes

Energy-filtered transmission electron microscopy (EFTEM) images of stacked Si/SiO2/Si nanopillars

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Permalink: https://www.hzdr.de/publications/Publ-32276
Publ.-Id: 32276


Data file for manuscript on Interfacial Properties of Tridecyl Dimethyl Phosphine Oxide Adsorbed at the Surface of a Solution Drop in Hexane Saturated Air

Javadi, A.

Experimental data for paper: Interfacial Properties of Tridecyl Dimethyl Phosphine Oxide Adsorbed at the Surface of a Solution Drop in Hexane Saturated Air.

The presented data are measured dynamic surface tension of Tridecyl Dimethyl Phosphine Oxide in water against air and alkane vapors, by profile analysis tensiometry. It also includes data analysis standard deviation from Young-Laplace fitting, and theoretical analysis illustrating isotherm of adsorption.

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Permalink: https://www.hzdr.de/publications/Publ-32274
Publ.-Id: 32274


Data File for Drop Size Dependence of the Apparent Surface Tension of Aqueous Solutions in Hexane Vapor

Javadi, A.

Experimental data file for Paper on "Drop Size Dependence of the Apparent Surface Tension of Aqueous Solutions in Hexane Vapor as Studied by Drop Profile Analysis Tensiometry".

These data are measured dynamic surface tension and variations of deviations from Young Laplace fitting, of different drop size of surfactants solution Tridecyl dimethyl phosphine oxide C13DMPO and Oxyethylated alcohol С14ЕО8 in water against air and hexane vapor. 

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Permalink: https://www.hzdr.de/publications/Publ-32273
Publ.-Id: 32273


Increasing the recycling rate of spent lithium ion battery recycling by recovering spheroidized graphite

Vanderbruggen, A.; Rudolph, M.

Lithium ion battery is composed of a lot of raw materials such as Co, Ni, Li, Al, Cu and graphite. Graphite represents around 20 wt. % of a lithium-ion battery. Graphite from spent lithium-ion batteries is rarely recovered and usually remains in slags from the metallurgical treatments. During lithium-ion battery recycling, the graphite particles end up are liberated from the copper foils and end up in the fine fraction (below 100 µm). This fraction is also composed of lithium metal oxides. Lithium metal oxides and graphite can be separated by froth flotation. The aim of this research is to increase the recycling recovery of the LiBs by developing a new innovative process, which minimizes metal losses and is able to recover graphite. Two valuable products, one of graphite and one with the valuable metals are recovered using a batch mechanically agitated Outotec flotation cell. Batch flotation study shows that pre-treatment, such as attritioning, improves the process. This research aims to reach closed-loop system for spheroidized graphite from spent LiB.

Keywords: Recycling; Lithium ion battery; Froth flotation; critical raw material; Graphite

  • Invited lecture (Conferences)
    10th Advanced Automotive battery conferences AABC 2020 - Battery recycling Symposium, 12.-16.01.2021, Wiesbaden, Germany

Permalink: https://www.hzdr.de/publications/Publ-32272
Publ.-Id: 32272


Characterization of lithium ion battery recycling processes and estimation of liberation efficiency of electrodes using automated mineralogy

Vanderbruggen, A.; Hayagan, N. L.; Bachmann, K.; Rudolph, M.

Lithium-ion batteries (LIBs) are currently one of the most important electrochemical energy storage devices, powering electronic mobile devices and electric vehicles. Growing global demands for Co, Mn, Ni, Li, and graphite which are all used and present in LIBs as energy storage added difficulties to the already deficit and imbalance supply of sources of raw materials worldwide, which resulted to supply risks, price fluctuations and monopoly of market. In fact, Co and natural graphite are listed as critical raw materials (CRMs) in Europe since 2010 and Mn, and Li are on the boundary of criticality. While recycling is identified as a solution to potentially reduce the gap between the demand and supply. Recycling of lithium ion battery (LIB) has attracted a lot of attention in the recent years and focuses primarily on valuable metals such as cobalt, nickel and lithium. During the recycling processes, considerable amount of the components are lost like electrolyte, separator or graphite. For instance, graphite can either be slagged-off or consumed as a reductant agent during pyrometallurgical treatment. Some other loses are due to a lack of liberation of the targeted particles, elements such as Co are lost in the coarse fractions and a not recovered in the right product. Hence, there is a need to find innovative and comprehensive LIB recycling operations.
For understanding and be able to quantify the loses and recycling process efficiency a deeper characterization is required. This research proposes a new characterization method based on automated mineralogy. In this study, the particles morphologies (size, composition and phases associations) are analysed. The liberation of active materials from electrodes is quantified by comparing two recycling processes: mechanical and thermochemical-mechanical. The mechanical route operates with an impact shear crusher while for the thermomechanical operation the batteries were vacuum pyrolyzed at 500-650oC before to be crushed. The black mass, fraction below 1 mm from the recycling processes, were classified in 4 size fractions based on the particles size distribution. Each fraction was characterized by various analytical methods, including X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Atomic Absorption Spectrometry (AAS) and SEM-based automated mineralogy. The latter consists in the combination of a scanning electron microscopy (SEM) image analysis and energy dispersive X-ray spectroscopy (EDS). It is a powerful and well-known method for primary material characterization; however, it has not yet been applied to secondary material such as black mass, which is a challenging material to analyse due fine alloys particles and to the lack of an existing dedicated database.
In this research, a database for battery characterization is also aimed aside from the determination of the liberation efficiency of the processes employed. Furthermore, a unique procedure was used in preparing the grain mounts for SEM-EDS analysis. Here, iodoform is added to modify the grey level of resin, which improves the contrast with the carbon phases. This technic allows the quantification of the carbon phases which is also a limitation of XRF and XRD aside from the fact that these methods cannot provide images for qualitative evaluation. This study showed that the thermo-mechanical process liberates more active particles from the foils than only a mechanical process. For both processes, a liberation selectivity of the electrode foils was observed. Cu foil is better liberated than Al foils. By consequence, most of the graphite particles are concentrated in the <63μm fraction. However, it was
found that the process type has different effects on Al foil liberation. The thermomechanical process liberates more metal oxides from the Al foil than only mechanical process, but Al breakage is more affected by thermal treatment, which creates finer Al particles, which can be problematic for further hydrometallurgy routes.

Keywords: Recycling; Lithium ion battery; Automated mineralogy; critical raw material; Graphite

  • Poster (Online presentation)
    10. ProcessNet-Jahrestagung und 34. DECHEMA-Jahrestagung der Biotechnologen 2020, 21.-24.09.2021, Online, Germany
  • Abstract in refereed journal
    Chemie Ingenieur Technik 92(2020)9, 1233
    DOI: 10.1002/cite.202055471

Permalink: https://www.hzdr.de/publications/Publ-32271
Publ.-Id: 32271


Spheroidized graphite from lithium-ion battery

Vanderbruggen, A.; Rudolph, M.

Spheroidized graphite is the major material used for anode production for lithium-ion batteries. Despite the growth in graphite consumption due to the electrical revolution and the fact that it is counted as a critical material in Europe, USA and Australia, there is little previous work focusing on graphite recycling. This talk will explain the importance of recycling graphite from spent lithium ion batteries and how graphite can be recovered.

Keywords: Recycling; Lithium ion battery; graphite; critical raw material

  • Invited lecture (Conferences) (Online presentation)
    Short course on Circular economy and sustainable material for li-battery, 18.-19.11.2021, Nancy, France

Permalink: https://www.hzdr.de/publications/Publ-32270
Publ.-Id: 32270


Recovery of spheroidized graphite from spent lithium-ion batteries

Vanderbruggen, A.; Rudolph, M.

Recycling of lithium ion battery has attracted a lot of attention and is particularly focusing on the valuable metals such as cobalt, nickel and lithium. Despite the growth in graphite consumption and the fact that it is counted as a critical material in Europe, USA and Australia, there is little previous work focusing on graphite recycling. Thus, graphite usually remains in slags from the metallurgical treatments. The aim of this research is to increase the recycling recovery of the LIBs by developing a new innovative process, which minimizes metal losses and is able to recover graphite. By integrating a flotation stage, this recycling process is able to separate battery electrode materials while preserving their functional integrity in order to reintegrate them in the value chain of LiB production. Two valuable products, one of graphite and one with the valuable metals are recovered using a batch mechanically agitated Outotec flotation cell. Batch flotation study shows that pre-treatment, such as attritioning, improves the process. The graphite recovery is +98 % with a grade of 80 wt. %. This research aims to reach closed-loop system for spheroidized graphite from spent LIBs.

Keywords: Recycling; Lithium ion battery; Froth flotation; Graphite; critical raw material

  • Invited lecture (Conferences)
    25th International Congress for Battery Recycling ICBR 2020, 16.-18.09.2021, Salzburg, Austria

Permalink: https://www.hzdr.de/publications/Publ-32269
Publ.-Id: 32269


Assessment of the liberation efficiency of lithium-ion battery components in recycling processes by using automated mineralogy

Vanderbruggen, A.; Bachmann, K.; Hayagan, N. L.; Rudolph, M.

Mechanical recycling processes aim at separating individual particles based on their properties, such as size, shape, density and composition. However, secondary material such as spent lithium ion battery are highly heterogeneous and complex in element and also material form. In order to improve recycling efficiency, characterization of the recycled products, on a particle level, is crucial. Nevertheless, conventional characterization techniques, such ICP-OES, XRF or XRD, provide bulked information for the products only. Tis research presents the development of a new analytical procedure based on individual particle characterization in order to monitor and diagnose lithium ion battery (LiB) recycling.
In this study, cylindrical lithium-ion batteries (INR18650-29E) are fed to a mechanical and thermo-mechanical recycling process route to release coated particles from the electrodes foils. In addition to the valuable metals, the focus is particularly on the recovery of graphite. The mechanical route works with a shear crusher, while for the thermo-mechanical tests the batteries were vacuum pyrolyzed at 500-650 °C before crushing. The fraction smaller than 1 mm, called black mass, was separated and classified into 4 size fractions based on the particle size distribution. The samples were analysed by automated mineralogy, this analytical tool enables the acquisition of particle-based information such as elemental and phase composition, morphology, association and degree of liberation. The Mineral Liberation Analyzer (MLA) system used for the measurements uses a combination of scanning electron microscopy (SEM) image analysis and energy-dispersive X-ray spectroscopy (EDS) and is established as a powerful method in the primary raw materials sector. However, there are no dedicated databases for use in the secondary raw materials sector in order to analyze black mass material in a fast and precise manner. An analytical challenge of this study is therefore to create a database for battery characterization and to be able to use it for a wide range of applications. The analysis shows a selective liberation of the anode components in comparison to the cathode components for the beneficiation processes, but with different liberation patterns of the Al foil. The lamination structure of the electrodes was conserved during mechanical process, which resultes in coarse aggregates. The thermo-mechanical process releases more individual and small aggregates of active particles from the foils than a mechanical process alone.

Keywords: Recycling; Lithium ion battery; Automated mineralogy; Black mass

  • Invited lecture (Conferences) (Online presentation)
    11th Advanced Automotive battery conferences AABC 2021 - Battery recycling Symposium, 19.-20.01.2021, Online, Germany

Permalink: https://www.hzdr.de/publications/Publ-32268
Publ.-Id: 32268


Brillouin Light Scattering Revisited

Schultheiß, K.; Schultheiß, H.

Since the 80’s, when Brillouin light scattering emerged as a powerful tool for investigating magnetization dynamics in thin films and multilayers, it developed into a versatile microscopic probe for studying collective spin excitations. Following a short introduction on studies of millimeter-sized films, we will give examples how to investigate individual magnetic structures down to tens of nanometers in dimension. We will introduce the concepts of time- and phase-resolved Brillouin light scattering which give full access to the spatio-temporal evolution of the optically accessible spin-wave spectrum. During our talk, we will provide hands-on demonstrations how to drive spin waves via spin currents and microwave excitations in magnetic nanostructures using the build in dc/ac probe station in our laboratory and show the capabilities of Brillouin light scattering for quantifying spin-wave phenomena. Furthermore, we will highlight similarities and differences to other optical scanning probe techniques such as time-resolved magneto-optical Kerr microscopy and optically detected magnetic resonance based on vacancy centers. We will outline how those techniques can potentially be combined with Brillouin light scattering to access complementary information.

Keywords: Brillouin light scattering; magnetization dynamics; spin waves; magneto optics

Related publications

  • Invited lecture (Conferences) (Online presentation)
    INTERMAG 2021, 26.-30.04.2021, online (planned: Lyon), online (planned: France)

Permalink: https://www.hzdr.de/publications/Publ-32267
Publ.-Id: 32267


Highlight selection of radiochemistry and radiopharmacy developments by editorial board (January-June 2020).

Al-Qahtani, M.; Behe, M.; Bormans, G.; Carlucci, G.; Dasilva, J.; Decristoforo, C.; Elsinga, P.; Kopka, K.; Li, X.; Mach, R.; Middel, O.; Passchier, J.; Patt, M.; Penuelas, I.; Rey, A.; Scott, P.; Todde, S.; Toyohara, J.; Vugts, D.

Background: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biyearly highlight commentary to describe trends in the field.
Results: This commentary of highlights has resulted in 19 different topics selected by each member of the Editorial Board addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals.
Conclusion: Trends in radiochemistry and radiopharmacy are highlighted demonstrating the progress in the research field being the scope of EJNMMI Radiopharmacy and Chemistry.

Permalink: https://www.hzdr.de/publications/Publ-32266
Publ.-Id: 32266


Curvilinear magnetism: fundamentals and applications

Makarov, D.

Extending 2D structures into 3D space has become a general trend in multiple disciplines including electronics, photonics, and magnetics. This approach provides means to enrich conventional or to launch novel functionalities by tailoring geometrical curvature and 3D shape. We study 3D curved magnetic thin films and nanowires where new fundamental effects emerge from the interplay of the geometry of an object and topology of a magnetic sub-system [1-4]. The lack of an inversion symmetry and the emergence of a curvature induced effective anisotropy and DMI are characteristic of curved surfaces, leading to curvature-driven magnetochiral responses and topologically induced magnetization patterning [5-7]. The possibility to tailor magnetic responses by geometry of the object is a new approach to material science, which allows to obtain a desired functionality of spintronic and spin-orbitronic devices yet without the need to rely on the optimization of the intrinsic material properties. The application potential of 3D-shaped magnetic thin films is currently being explored as mechanically shapeable magnetic field sensors [8] for automotive applications, magnetoelectrics for memory devices, spin-wave filters, high-speed racetrack memory devices as well as on-skin interactive electronics [9-11]. The magnetosensitive smart skins allow digitizing the bodily motion and offer new means of touchless manipulation of virtual objects based on the interaction with magnetic stray fields of small permanent magnets [9,11] but also with geomagnetic field [10]. The fundamentals as well as application relevant aspects of curvilinear magnetism will be covered in this presentation.

[1] R. Streubel et al., Magnetism in curved geometries. J. Phys. D: Appl. Phys. (Review) 49, 363001 (2016).
[2] D. Sander et al., The 2017 magnetism roadmap. J. Phys. D: Appl. Phys. (Review) 50, 363001 (2017).
[3] O. M. Volkov et al., Experimental observation of exchange-driven chiral effects in curvilinear magnetism. Phys. Rev. Lett. 123, 077201 (2019).
[4] D. Sheka et al., Nonlocal chiral symmetry breaking in curvilinear magnetic shells. Communications Physics 3, 128 (2020)
[5] V. Kravchuk et al., Multiplet of Skyrmion states on a curvilinear defect: Reconfigurable Skyrmion lattices. Phys. Rev. Lett. 120, 067201 (2018)
[6] O. Pylypovskyi et al., Chiral Skyrmion and Skyrmionium States Engineered by the Gradient of Curvature. Phys. Rev. Appl. 10, 064057 (2018)
[7] O. Pylypovskyi et al., Coupling of chiralities in spin and physical spaces: The Möbius ring as a case study. Phys. Rev. Lett. 114, 197204 (2015)
[8] D. Makarov et al., Shapeable magnetoelectronics. Appl. Phys. Rev. (Review) 3, 011101 (2016).
[9] G. S. Cañón Bermúdez et al., Magnetosensitive e-skins with directional perception for augmented reality. Science Advances 4, eaao2623 (2018).
[10] G. S. Cañón Bermúdez et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoception and interactive electronics. Nature Electronics 1, 589 (2018).
[11] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).

Keywords: flexible electronics; curvilinear magnetism; magnetosensitive smart skins

Related publications

  • Lecture (others) (Online presentation)
    Seminar at the University of Kiel, 11.02.2021, Kiel, Germany

Permalink: https://www.hzdr.de/publications/Publ-32265
Publ.-Id: 32265


Mechanisms of pyrite biodepression with Acidithiobacillus ferrooxidans in seawater flotation

San Martin, F.; Kracht, W.; Vargas, T.; Rudolph, M.

It has been shown that bacterium Acidithiobacillus ferrooxidans can be used to depress pyrite in seawater flotation at natural pH, which opens the possibility for its use as an alternative to lime to depress pyrite in copper sulfide flotation. In order to have a better understanding of the mechanisms involved in pyrite depression with A. ferrooxidans, different kind of experiments were carried out, including, contact angle, attachment kinetics, and streaming potential measurements. All these experiments were carried out in seawater. Biodepression of pyrite was improved by increasing the pH from 4 to 8, with a decrease in recovery from 92% to 36%. This increase in depressing capability was accompanied by an increase in attachment density of bacteria on pyrite, from bacteria/g to bacteria/g at pH 4 and 8, respectively. These results suggest that the mechanism of depression is related to the attachment of bacteria to the pyrite surface. The streaming potential measurements showed that both bacteria and pyrite were negatively charged at pH 8. This indicates that electrostatic forces are mainly repulsive, therefore other forces cause the attachment of bacteria to the mineral. The contact angle of pyrite conditioned with seawater at pH 8 was 16, which increased to 54 when collector (sodium isopropyl xanthate) was added, indicating an increase in hydrophobicity. Nevertheless, when pyrite was previous conditioned with bacteria, the contact angle increased only to 44 when collector was added. Thus, the collector has a lower influence in the hydrophobicity of pyrite when the mineral has interacted with bacteria A. ferrooxidans.

Keywords: Flotation; Seawater; Pyrite; Biodepression; Acidithiobacillus ferrooxidans

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Permalink: https://www.hzdr.de/publications/Publ-32264
Publ.-Id: 32264


Advanced Analysis of Bubble Columns: Comparison of Euler/Lagrange Simulations and Experiments under CO2 chemisorption conditions

Taborda, M. A.; Kipping, R.; Hampel, U.; Sommerfeld, M.

The chemical absorption reaction of CO2 in a circular bubble column reactor was simulated with an Euler/Lagrange CFD method and results were compared with data from a laboratory scale bubble column. The experimental data comprises gas holdup and bubble size distributions obtained with ultrafast X-ray tomography and hydroxide ion conversion obtained with a wire-mesh sensor. Large Eddy Simulation (LES) is used for calculating the fluid flow and modelling the turbulence in the continuous phase, considering the effect of sub-grid-scale (SGS) turbulence on bubble motion, and also SGS turbulence modification by bubbles. Lagrangian bubble tracking is conducted considering all relevant forces, bubble oscillation via stochastic generation of eccentricity and motion angle and consequently non-steady mass transfer via a dynamic Sherwood number. The comparison of experimental and simulation results shows very good agreement for the given data.

Keywords: Euler/Lagrange approach; bubble dynamics model; reactive two-phase flow; dynamic Sherwood number; wire-mesh sensor; ultrafast X-ray computed tomography

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Permalink: https://www.hzdr.de/publications/Publ-32261
Publ.-Id: 32261


Study of the parameter dependence of laser-accelerated protons from a hydrogen cluster source

Aurand, B.; Schwind, K. M.; Toncian, T.; Aktan, E.; Cerchez, M.; Lessmann, L.; Mannweiler, C.; Prasad, R.; Khoukaz, A.; Willi, O.

We present a study on laser-driven proton acceleration from a hydrogen cluster target. Aiming for the optimisation of the proton source, we performed a detailed parametric scan of the interaction conditions by varying different laser and the target parameters. While the underlying process of a Coulomb-explosion delivers moderate energies, in the range of 100 s of keV, the use of hydrogen as target material comes with the benefit of a debris-free, single-species proton acceleration scheme, enabling high repetition-rate experiments, which are very robust against shot-to-shot fluctuations.

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Permalink: https://www.hzdr.de/publications/Publ-32260
Publ.-Id: 32260


Direct laser acceleration of electrons assisted by strong laser-driven azimuthal plasma magnetic fields

Gong, Z.; Mackenroth, F.; Wang, T.; Yan, X. Q.; Toncian, T.; Arefiev, A. V.

A high-intensity laser beam propagating through a dense plasma drives a strong current that robustly sustains a strong quasistatic azimuthal magnetic field. The laser field efficiently accelerates electrons in such a field that confines the transverse motion and deflects the electrons in the forward direction. Its advantage is a threshold rather than resonant behavior, accelerating electrons to high energies for sufficiently strong laser-driven currents. We study the electron dynamics via a test-electron model, specifically deriving the corresponding critical current density. We confirm the model's predictions by numerical simulations, indicating energy gains two orders of magnitude higher than achievable without the magnetic field.

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Permalink: https://www.hzdr.de/publications/Publ-32259
Publ.-Id: 32259


Application of Laser-Driven Capacitor-Coil to Target Normal Sheath Acceleration

Morita, H.; Arefiev, A.; Toncian, T.; Jorge Santos, J.; Golovin, D.; Shokita, S.; Mori, T.; Fai Farley Law, K.; Li, H.; Takizawa, R.; Matsuo, K.; Morace, A.; Yogo, A.; Fujioka, S.

A laser-driven accelerator generates protons with tens of MeV in energy by a compact, strong, and transient accelerating electric field produced as a result of laser–plasma interactions at relativistic intensities. In previous studies, two- and three-dimensional particle-in-cell simulations revealed that the application of a kT-level axial magnetic field results in an enhancement of proton acceleration via the target normal sheath acceleration mechanism due to reduced lateral electron divergence and improved electron heating efficiency. An experimental investigation of this scheme on the GEKKO-XII and the LFEX facilities found that the number and maximum energy of the accelerated protons decreased with increasing the temporal delay between the pulse driving the external magnetic-field and the pulse accelerating the protons, contrary to the theoretical and numerical expectations. We identify sources responsible for the degradation of the proton beam performance and we propose an alternative experimental setup to mitigate the degradation in future experiments.

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Permalink: https://www.hzdr.de/publications/Publ-32258
Publ.-Id: 32258


Generation of focusing ion beams by magnetized electron sheath acceleration

Weichman, K.; Santos, J. J.; Fujioka, S.; Toncian, T.; Arefiev, A. V.

We present the first 3D fully kinetic simulations of laser driven sheath-based ion acceleration with a kilotesla-level applied magnetic field. The application of a strong magnetic field significantly and beneficially alters sheath based ion acceleration and creates two distinct stages in the acceleration process associated with the time-evolving magnetization of the hot electron sheath. The first stage delivers dramatically enhanced acceleration, and the second reverses the typical outward-directed topology of the sheath electric field into a focusing configuration. The net result is a focusing, magnetic field-directed ion source of multiple species with strongly enhanced energy and number. The predicted improvements in ion source characteristics are desirable for applications and suggest a route to experimentally confirm magnetization-related effects in the high energy density regime. We additionally perform a comparison between 2D and 3D simulation geometry, on which basis we predict the feasibility of observing magnetic field effects under experimentally relevant conditions.

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Permalink: https://www.hzdr.de/publications/Publ-32257
Publ.-Id: 32257


A laser-driven droplet source for plasma physics applications

Aurand, B.; Aktan, E.; Schwind, K. M.; Prasad, R.; Cerchez, M.; Toncian, T.; Willi, O.

In this paper, we report on the acceleration of protons and oxygen ions from tens of micrometer large water droplets by a high-intensity laser in the range of 1020 W/cm2. Proton energies of up to 6 MeV were obtained from a hybrid acceleration regime between classical Coulomb explosion and shocks. Besides the known thermal energy spectrum, a collective acceleration of oxygen ions of different charge states is observed. 3D PIC simulations and analytical models are employed to support the experiential findings and reveal the potential for further applications and studies.

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Permalink: https://www.hzdr.de/publications/Publ-32256
Publ.-Id: 32256


A new approach to monitor 13C-targets degradation in situ for 13C(α,n)16O cross-section measurements at LUNA

Ciani, G. F.; Csedreki, L.; Balibrea-Correa, J.; Best, A.; Aliotta, M.; Barile, F.; Bemmerer, D.; Boeltzig, A.; Broggini, C.; Bruno, C. G.; Caciolli, A.; Cavanna, F.; Chillery, T.; Colombetti, P.; Corvisiero, P.; Davinson, T.; Depalo, R.; Di Leva, A.; Di Paolo, L.; Elekes, Z.; Ferraro, F.; Fiore, E. M.; Formicola, A.; Fülöp, Z.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, G.; Imbriani, G.; Junker, M.; Kochanek, I.; Lugaro, M.; Marigo, P.; Masha, E.; Menegazzo, R.; Mossa, V.; Pantaleo, F. R.; Paticchio, V.; Perrino, R.; Piatti, D.; Prati, P.; Schiavulli, L.; Stöckel, K.; Straniero, O.; Szücs, T.; Takács, M. P.; Terrasi, F.; Trezzi, D.; Zavatarelli, S.

Direct measurements of reaction cross-sections at astrophysical energies often require the use of solid targets able to withstand high ion beam currents for extended periods of time. Thus, monitoring target thickness, isotopic composition, and target stoichiometry during data taking is critical to account for possible target modifications and to reduce uncertainties in the final cross-section results. A common technique used for these purposes is the Nuclear Resonant Reaction Analysis (NRRA), which however requires that a narrow resonance be available inside the dynamic range of the accelerator used. In cases when this is not possible, as for example the 13C(𝛼,n)16O reaction recently studied at low energies at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Italy, alternative approaches must be found. Here, we present a new application of the shape analysis of primary γ rays emitted by the 13C(p,𝛾)14N radiative capture reaction. This approach was used to monitor 13C target degradation in situ during the 13C(𝛼,n)16O data taking campaign. The results obtained are in agreement with evaluations subsequently performed at Atomki (Hungary) using the NRRA method. A preliminary application for the extraction of the 13C(α,n)16O reaction cross-section at one beam energy is also reported.

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Permalink: https://www.hzdr.de/publications/Publ-32255
Publ.-Id: 32255


Sorption studies of Np(V) onto the zircaloy corrosion product ZrO₂

Jessat, I.; Foerstendorf, H.; Jordan, N.

The interactions of dissolved radionuclides, such as the actinide neptunium(V), with corroded phases in the near field of a repository are crucial processes to be considered in a safety assessment of a nuclear waste disposal for highly radioactive waste. Zirconia (ZrO₂), the corrosion product of the zircaloy cladding material of spent nuclear fuel rods, represents one of the first barriers encountered by mobilized radionuclide ions.
In this study, the interactions between Np(V) and monoclinic zirconia were studied at room temperature on a macroscopic and molecular scale. The influence of different parameters (time, pH, ionic strength, [Np(V)]) was investigated by means of batch sorption experiments to gain information on the macroscopic level. Starting at pH 3, an increased uptake of Np(V) with increasing pH was observed, reaching its maximum at pH ≥ 7. The Np(V) sorption was found to be independent of ionic strength, indicating Np(V) inner-sphere complexation on the ZrO₂ surface. This finding was supported by electrophoretic mobility measurements at different Np(V) concentrations. A shift of the isoelectric point of the neat ZrO₂ to higher pH values in the presence of Np(V) suggests the same Np(V) binding mode.
In situ ATR-FTIR spectroscopy was applied to gain a deeper understanding of the Np(V) sorption processes on a molecular level. These experiments allow a thorough characterization of the surface speciation including the number of occurring species, their denticity, and their reversibility of formation. Subsequently, this information will be used for the surface complexation modelling (SCM) to parametrize a comprehensive description of the Np(V)-ZrO₂ system, which in turn will contribute to a more reliable prediction of the fate of Np(V) in the environment.

Keywords: neptunium(V); zirconia; sorption; spectroscopy

  • Lecture (Conference)
    Goldschmidt 2021, 04.-09.07.2021, Lyon, France

Permalink: https://www.hzdr.de/publications/Publ-32254
Publ.-Id: 32254


Data for: The surface expression of hydrocarbon seeps characterized by satellite image spectral analysis and rock magnetic data (Falcon basin, western Venezuela)

de La Rosa, R.; Aldana, M.; Costanzo-Alvarez, V.; Yepez, S.; Amon, C.

This work integrates satellite image spectral analyses with rock magnetic and geochemical data (i.e., mass-specific magnetic susceptibility χ, saturation isothermal remanent magnetization SIRM, analysis of SIRM acquisition curves, absorption spectro-radiometry, and X-ray diffraction analyses). The target area was an oil-prospective region in northwestern Venezuela (Falcon Basin) swarmed by hydrocarbon seeps. The study's main goal was to depict the spatial extension and vertical reach of the hydrocarbon-mediated alteration produced by these seeps and gain some knowledge about the processes involved in the subsequent mineral changes.

The dataset is composed of spreadsheets, compressing field samples data including their locations. Also, a database is presented with data from profiles extracted from the results of multispectral image processing and laboratory data of rock magnetism. 

Keywords: Satellite remote sensing; Spectral images; Spectral signature; Hydrocarbon seeps; Hydrocarbon- induced diagenesis; Rock magnetism; Weathered sequence; Two-Step Cluster Analysis

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Permalink: https://www.hzdr.de/publications/Publ-32253
Publ.-Id: 32253


The application of surface exposure dating method in case of Veliki vrh rockfall (Karavanke Mountains, Slovenia)

Mrak, I.; Merchel, S.; Braucher, R.; Benedetti, L.; Finkel, R. C.; Bourlès, D.

The use of terrestrial cosmogenic nuclides (TCN) has revolutionized Earth surface sciences over the last decade by their capacity to quantify geological surface processes. The uniqueness of these nuclides lies in their property of being produced in the top few meters of the lithosphere during exposure to cosmic radiation. There are various types of application of surface exposure dating such as chronological constraints on the timing and rates of environmental changes (glacial history, erosion) and hazard recurrence frequency (landslides and seismic activity). The method was used also in the case of Veliki vrh rockfall located in Karavanke Mountains (Slovenia). There are no reliable historical data about the rockfall event beside the oral heritage in form of a fairytale describing the catastrophic falling of rocks over the settlement in the valley, forcing the survivors to establish a new settlement (Tržic) further downstream. However, there are numerous written records about a historic rockfall (induced by an earthquake) taking place about 46 km away at Dobratsch, Carinthia on 25th January 1348 thus; it seems very likely that the same earthquake triggered both rockfalls. Surface exposure dating method has been applied on samples taken from the fresh bedrock and big blocks obviously originating from the Veliki vrh rockfall and the results are confirming our
hypothesis. They have also importantly improved geomorphologic interpretation of the area.

Keywords: AMS; cosmogenic radionuclide; rockfall; earthquake; dating

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  • Lecture (Conference)
    Association of American Geographers 2011 Annual Meeting, 10.-16.04.2011, Seattle, Washington, USA

Permalink: https://www.hzdr.de/publications/Publ-32252
Publ.-Id: 32252


Lipase At water air intereface data HZDR TUB 2018-2020

Javadi, A.

Dynamic surface tension and competitive adsorption of Lipase enzyme and surfactants at water air interface.

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Permalink: https://www.hzdr.de/publications/Publ-32251
Publ.-Id: 32251


alpaka, LLAMA & Vc: An ecosystem for performance portable parallelism

Stephan, J.

This talk covers the alpaka ecosystem for performance portable parallel programming in HPC and simulation environments. It focuses on alpaka, LLAMA and Vc, their interactions with each other and their impact on the C++ programming language.

Keywords: alpaka; LLAMA; Vc; C++; heterogeneous programming; portability; HPC; parallel programming

  • Open Access Logo Lecture (others) (Online presentation)
    7th MT Meeting, 01.-03.02.2021, Hamburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32250
Publ.-Id: 32250


Dataset for: Flow morphologies in straight and bent horizontal pipes (uncalibrated measurement files)

Döß, A.; Schubert, M.; Wiedemann, P.; Schleicher, E.; Hampel, U.

This data set is a supplementory to 'Dataset for: Flow morphologies in straight and bent horizontal pipes'. In addition to the void files (.v) given in the primary data sets we provide:

- Underlying uncalibrated measurements files (.dat, .dati)
- .log files for the corresponding .v-files
- Calibration measurements
- Geometry files for the used Wire-mesh sensors

Keywords: Flow morphologies; Horizontal Two-phase flow; Wire-mesh sensor; TERESA

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Permalink: https://www.hzdr.de/publications/Publ-32249
Publ.-Id: 32249


Data-driven magneto-elastic predictions with scalable classical spin-lattice dynamics

Nikolov, S.; Wood, M. A.; Cangi, A.; Maillet, J.-B.; Marinica, M.-C.; Thompson, A. P.; Desjarlais, M. P.; Tranchida, J.

A data-driven framework is presented for building magneto-elastic machine-learning interatomic potentials (ML-IAPs) for large-scale spin-lattice dynamics simulations. The magneto-elastic ML-IAPs are constructed by coupling a collective atomic spin model with an ML-IAP. Together they represent a potential energy surface from which the mechanical forces on the atoms and the precession dynamics of the atomic spins are computed. Both the atomic spin model and the ML-IAP are parametrized on data from first-principles calculations. We demonstrate the efficacy of our data-driven framework across magneto-structural phase transitions by generating a magneto-elastic ML-IAP for α-iron. The combined potential energy surface yields excellent agreement with first-principles magneto-elastic calculations and quantitative predictions of diverse materials properties including bulk modulus, magnetization, and specific heat across the ferromagnetic–paramagnetic phase transition.

Keywords: magnetism; molecular dynamics; spin dynamics; lattice dynamics; density functional theory; machine learning; interatomic potentials

Permalink: https://www.hzdr.de/publications/Publ-32248
Publ.-Id: 32248


Spin Dynamics in Quantum Sine-Gordon Spin Chains: High-Field ESR Studies

Zvyagin, S.

A spin-1/2 Heisenberg antiferromagnetic chain is one of the most important paradigmatic models in quantum magnetism. Its ground state is a spin singlet, while the excitation spectrum is formed by gapless fractional excitations, spinons. The presence of alternating g-tensors and/or the staggered Dzyaloshinskii-Moriya interaction results in opening the energy gap Δ∝H2/3, once the magnetic field H is applied. A fairly good understanding of this phenomenon was achieved in the framework of the sine-Gordon quantum-field theory, taking into account the effective transverse staggered field induced by the applied uniform field. The theory predicts solitons and antisolitons as elementary excitations, as well as their bound states, breathers. Here, I review recent high-field electron spin resonance spectroscopy studies of such systems, focusing on peculiarities of their spin dynamics in the sine-Gordon regime and beyond.

Permalink: https://www.hzdr.de/publications/Publ-32247
Publ.-Id: 32247


Die Bedeutung des Elementes Barium in der Nuklearmedizin

Reissig, F.; Kopka, K.; Mamat, C.

Von Erdalkalimetallionen außer Beryllium ist bekannt, dass sie ein calcimimetisches Verhalten zeigen. Damit ist ihr Schicksal in vivo vorgezeichnet, das in einem beträchtlichen Maße durch den Einbau in Knochengewebe, welches zum Hauptteil aus Hydroxylapatit besteht, charakterisiert ist. In diesem Sinne wurde auch die Verwendung von Radionukliden dieser Elemente als Knochensucher forciert. Mit Ausnahme von Beryllium und Magnesium wurden Tierexperimente und Humananwendungen mit Radionukliden von Calcium, Strontium, Barium und Radium durchgeführt, wobei bis heute lediglich Strontium und Radium, in der Hauptsache als Therapienuklide zur palliativen Behandlung von Knochenmetastasen, Eingang in nuklearmedizinische Routineanwendungen gefunden haben. In diesem Übersichtsartikel werden die Radionuklide des Bariums vorgestellt, sowie deren Herstellung und Verwendung. Aktuelle Forschungsergebnisse mit Radionukliden des Bariums in Radiopharmazie und Nuklearmedizin werden präsentiert.

Keywords: Bariumisotope; Knochensucher; Radium

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Permalink: https://www.hzdr.de/publications/Publ-32246
Publ.-Id: 32246


Open-source computational model for polymer electrolyte fuel cells

Weber, N.; Knüpfer, L.; Beale, S. B.; Lehnert, W.; Reimer, U.; Zhang, S.; Ferreira-Aparicio, P.; M. Chaparro, A.

Open-source fuel cell models outmatch commercial codes in many important aspects. By providing the source code, reuse, modification and extension of the model and comparison with other codes becomes possible. With this motivation, we present a three-dimensional, steady-state, non-isothermal proton exchange membrane fuel cell model, implemented in the open-source finite volume library OpenFOAM® . At every stage of implementation, special care was taken to ensure a well documented, organised, and modular structure of the software. The resulting model suite can, and should, be extended with new sub-modules by the user. The main field of application, modelling of fuel cells from an engineering perspective, is demonstrated by simulating two different conventional polymer electrolyte fuel cells, operated at CIEMAT and Forschungszentrum Jülich, respectively.

  • Open Access Logo OpenFOAM Journal 2(2023), 26-48
    DOI: 10.51560/ofj.v3.50
    ISSN: 2753-8168
  • Software in external data repository
    Publication year 2021
    Programming language: C++
    System requirements: OpenFOAM-v2012
    License: GNU GPLv3
    Hosted on GitLab: Link to location

Permalink: https://www.hzdr.de/publications/Publ-32245
Publ.-Id: 32245


Data for: Single-step, High Pressure, and Two-Step Spark Plasma Sintering of UO2 nanopowders

de Bona, E.

Three different Spark Plasma Sintering (SPS) treatments were applied to highly sinteractive, near-stoichiometric UO2.04 nanocrystalline (5 nm) powders produced by U(IV) oxalate hydrothermal decomposition at 170 °C. The sintering conditions for reaching 95 % Theoretical Density (TD) in regular SPS, high pressure SPS (HP-SPS), and, for the first time, two-step SPS (2S-SPS), were determined. Densification to 95 % TD was achieved at 1000 °C in regular SPS (70 MPa applied pressure), 660 °C in HP-SPS (500 MPa), and 650-550 °C in 2S-SPS (70 MPa). With the goal of minimising the grain growth during densification, the sintering treatments were optimised to favour densification over coarsening, and the final microstructures thus obtained are compared. Equally dense UO2 samples of different grain sizes, ranging from 3.08 µm to 163 nm, were produced. Room-temperature oxidation of the powders could not be avoided due to their nanometric dimensions, and a final annealing treatment was designed to reduce hyperstoichiometric samples to UO2.00.

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Permalink: https://www.hzdr.de/publications/Publ-32243
Publ.-Id: 32243


Validation of an LC-MS/MS method to quantify the new TRPC6 inhibitor SH045 (larixyl N-methylcarbamate) and its application in an exploratory pharmacokinetic study in mice

Chai, X.-N.; Ludwig, F.-A.; Müglitz, A.; Schaefer, M.; Yin, H.-Y.; Brust, P.; Regenthal, R.; Krügel, U.

TRPC6 (transient receptor potential cation channels; canonical subfamily C, member 6) are widespread localized in mammalian organs like kidney and lung and associated with progressive proteinuria and pathophysiological pulmonary alterations like reperfusion edema or lung fibroses. However, the understanding of TRPC6 channelopathies is still at the beginning. Recently, by chemical diversification of (+)-larixol originating from Larix decidua resin traditionally used for inhalation, its methyl carbamate congener, named SH045, was obtained and identified in functional assays as highly potent, subtype-selective inhibitor of TRPC6. To pave the way for use of SH045 in animal disease models we aimed to develop a capable bioanalytical method and to provide exploratory pharmacokinetic data for this promising derivative. According to international guidelines, a robust and selective LC-MS/MS method based on MRM detection in positive ion mode was established and validated for quantification of SH045 in mice plasma, whereby linearity and accuracy were demonstrated for the range of 2-1600 ng/mL.
Applying this method, the plasma concentration time course of SH045 following single intraperitoneal administration (20 mg/kg body weight) revealed a rather short half-life of 1.3 hours. However, the pharmacological profile of SH045 is promising as five hours after administration plasma levels still remained sufficiently higher than published low nanomolar IC50 values.
Summarizing, the LC-MS/MS quantification method and exploratory pharmacokinetic data provide important prerequisites for experimental pharmacological TRPC6 modulation and translational treatment of TRPC6 channelopathies.

Keywords: channelopathies; larixol; labdane; LC-MS/MS; mice; pharmacokinetics; SH045; TRP channels; TRPC6 inhibitor

Permalink: https://www.hzdr.de/publications/Publ-32242
Publ.-Id: 32242


Development of a ghrelin receptor inverse agonist for positron emission tomography

Bergmann, R.; Chollet, C.; Els-Heindl, S.; Ullrich, M.; Berndt, N.; Pietzsch, J.; MáThé, D.; Bachmann, M.; Beck-Sickinger, A. G.

Imaging of Ghrelin receptors in vivo provides unique potential to gain deeper understanding on Ghrelin and its receptors in health and disease, in particular, in cancer. Ghrelin, an octanoylated 28-mer peptide hormone activates the constitutively active growth hormone secretagogue receptor type 1a (GHS-R1a) with nanomolar activity. We developed novel compounds, derived from the potent inverse agonist K-(D-1-Nal)-FwLL-NH2 but structurally varied by lysine conjugation with 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA), palmitic acid and/or diethylene glycol (PEG2) to allow radiolabeling and improve pharmacokinetics, respectively. All compounds were tested for receptor binding, potency and efficacy in vitro, for biodistribution and -kinetics in rats and in preclinical prostate cancer models on mice. Radiolabeling with Cu-64 and Ga-68 was successfully achieved. The Cu-64- or Ga-68-NODAGA-NH-K-K-(D-1-NaI)-F-w-L-L-NH2 radiotracer were specifically accumulated by the GHS-R1a in xenotransplanted human prostate tumor models (PC-3, DU-145) in mice. The tumors were clearly delineated by PET. The radiotracer uptake was also partially blocked by K-(D-1-Nal)-FwLL-NH2 in stomach and thyroid. The presence of the GHS-R1a was also confirmed by immunohistology. In the arterial rat blood plasma, only the original compounds were found. The Cu-64- or Ga-68-NODAGA-NH-K-K-(D-1-NaI)-F-w-L-L-NH2 radiolabeled inverse agonists turned out to be potent and safe. Due to their easy synthesis, high affinity, medium potency, metabolic stability, and the suitable pharmacokinetic profiles, they are excellent tools for imaging and quantitation of GHS-R1a expression in normal and cancer tissues by PET. These compounds can be used as novel biomarkers of the Ghrelin system in precision medicine.

Keywords: Cancer; Prostate cancer; growth hormone secretagogue receptor (GHS-R); small animal imaging; Copper-64; Gallium-68

Permalink: https://www.hzdr.de/publications/Publ-32241
Publ.-Id: 32241


Non-radiative energy transfer and selective charge transfer in a WS2/(PEA)2PbI4 heterostructure

Karpińska, M.; Liang, M.; Kempt, R.; Finzel, K.; Kamminga, M.; Zhang, N.; Knodlseder, C.; Maude, D. K.; Baranowski, M.; Łopotowski, Ł.; Ye, J.; Kuc, A. B.; Plochocka, P.

Van der Waals heterostructures are currently the focus of intense investigation, this is essentially due to the unprecedented flexibility offered by the total relaxation of lattice matching requirements, and their new and exotic properties compared to the individual layers. Here, we investigate the hybrid transition metal dichalcogenide/2D perovskite heterostructure WS2 /(PEA)2 PbI4 . We present the first DFT calculations of a heterostructure ensemble, which reveal a novel band alignment, where direct electron transfer is blocked by the organic spacer of the 2D perovskite. In contrast, the valence band forms a cascade from WS2 through the PEA to the PbI4 layer allowing hole transfer. These predictions are supported by optical spectroscopy studies, which provide compelling evidence for both charge transfer, and non-radiative transfer of the excitation (energy transfer) between the layers. Our results show that TMD/2D perovskite heterostructures provide a flexible and convenient way to engineer the band alignment.

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Permalink: https://www.hzdr.de/publications/Publ-32240
Publ.-Id: 32240


Data for: Experimental investigation of the return flow instability in magnetic spherical Couette flow

Ogbonna, J. E.; Garcia Gonzalez, F.; Gundrum, T.; Seilmayer, M.; Stefani, F.

Experimental data, numerical data, and programming scripts

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Permalink: https://www.hzdr.de/publications/Publ-32239
Publ.-Id: 32239


Guided capped particles propulsion via hydrogen peroxide decomposition under magnetic field

Alsaadawi, Yara; Heigl, M.; Eichler-Volf, A.; Albrecht, M.; Erbe, A.

Janus particles are one type of artificial microswimmers consisting of two asymmetrically functionalized surfaces. With proper manipulation, one can control their displacement from one point to another at a certain rate, clustering, and orientation. In this work, we employed capped Janus particles. The caps consisted of several alternating thin layers of Co and Pd, and sealed with a 2.1-nm Pd layer, giving a total cap thickness of 17 nm. The Co/Pd combination provides both, magnetic and H2O2 – catalytic properties for the cap, respectively. These unique properties lead to particle propulsion upon applying an external stimulus. To employ both mechanisms, we investigated propulsion under different combinations of H2O2 concentrations and magnetic fields. Since the magnetic element in the cap plays a critical role in cap orientation and mutual interaction, thereby promoting particle clustering1, we studied one particle system as well as two- and three-particle systems. Furthermore, as the swimming behavior is highly affected by the boundary conditions of its surrounding environment2, varying surface properties were incorporated during the experiments.

  • Poster (Online presentation)
    Microswimmers – From Single Particle Motion to Collective Behaviour, 26.-29.10.2020, Bonn, Germany

Permalink: https://www.hzdr.de/publications/Publ-32238
Publ.-Id: 32238


Ultra-High Negative Infrared Photoconductance in Highly As-doped Germanium Nanowires Induced by Hot Electron Trapping

John, J.; Dhyani, V.; Georgiev, Y.; Gangnaik, A.; Biswas, S.; Holmes, J.; Das, A.; Ray, S.; Das, S.

Here, we report the observation of negative photoconductance (NPC) effect in highly arsenic-doped germanium nanowires (Ge NWs) for the infrared light. NPC was studied by light-assisted Kelvin probe force microscopy, which shows the depletion of carriers in n-Ge NWs in the presence of infrared light. The trapping of photocarriers leads to high recombination of carriers in the presence of light, which is dominant in the n-type devices. Furthermore, a carrier trapping model was used to investigate the trapping and detrapping phenomena and it was observed that the NPC in n-Ge occurred, because of the fast trapping of mobile charge carriers by interfacial states. The performance of n-type devices was compared with p-type NW detectors, which shows the conventional positive photoconductive behavior with high gain of 104. The observed results can be used to study the application of Ge NWs for various optoelectronic applications involving light tunable memory device applications.

Keywords: negative photoconductivity; infrared detection; hot electron trapping; germanium nanowire; diameter-dependent photoconductance

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Permalink: https://www.hzdr.de/publications/Publ-32237
Publ.-Id: 32237


Towards Scalable Reconfigurable Field Effect Transistor using Flash Lamp Annealing

Khan, M. B.; Ghosh, S.; Prucnal, S.; Mauersberger, T.; Hübner, R.; Simon, M.; Mikolajick, T.; Erbe, A.; Georgiev, Y.

Introduction: For decades the miniaturization of logic circuitry was a result of down scaling of the field effect transistor (FET). This scaling has reached its end and, therefore, new device materials and concepts have been under research for the last years. One approach is to increase the functionality of an individual device rather than scaling down its size. Such a device concept is the reconfigurable FET (RFET), which can be configured to n- or p-polarity dynamically [1].
RFETs are based on Schottky barrier FETs and feature an intrinsic Si nanowire (NW) channel. The Schottky junctions are formed by placing Nickel (Ni) contacts on both ends of the NW and conductive Ni-silicide segments are formed in the NW by an annealing process. In RFETs, two gates are usually placed on top of these Schottky junctions and by the application of electrostatic potential at the gates unipolar n- or p-transport is tuned in the channel. There are several Ni-silicide phases out of which NiSi2 is preferred as it yields sharp NiSi2-Si junctions. Moreover, its metal work function is near the mid bandgap of Si. This enables tuning the RFET to n- or p-transport by respectively bending the bands when applying electrostatic potential at the gates (Fig. 1).
Top-down fabrication of Schottky barrier FETs is a pre-requisite for the large-scale integration of RFETs. The challenges in this fabrication process include proper patterning of NWs, obtaining symmetric p- and n-currents and the scalability of the devices. The first two tasks have been solved as reported in [2]. However, the lack of controllable intrusion of silicide into the NWs remains an obstacle for device scalability [3-5]. Here we report that a silicidation process based on millisecond flash lamp annealing (FLA) significantly improves the uniformity of silicide intrusion at the two ends of the NWs. Such a gain in silicidation control will decisively allow creating RFETs with short channel lengths.
Fabrication: The devices are fabricated on silicon-on-insulator (SOI) substrates with 20 nm undoped top Si layer and 102 nm buried oxide. Electron beam lithography (EBL) and dry etching are used to fabricate NWs with 20 nm width as described in [3]. NWs are oxidized with a rapid thermal process and a ~6 nm thick SiO2 shell is formed to passivate NW surface. After wet etching SiO2 from desired areas, Ni contacts are placed in those areas using EBL and Ni evaporation. FLA is used for silicidation of the NWs and the results show equally long silicide intrusions (Fig. 2).
Results: The FLA process time is much shorter (0.5-20 ms) compared to conventional rapid thermal annealing (RTA) [6]. FLA based silicidation process is developed which, unlike previously reported RTA based processes, can deliver scalable RFETs. High resolution TEM (HRTEM) shows the formation of the desired NiSi2 phase and atomically abrupt Schottky junctions (Fig. 4). This is also confirmed by element mapping based on energy dispersive X-ray spectroscopy (EDXS) (Fig. 3). The transfer characteristics of the device with back-gate operation show an ambipolar behavior with an ON/OFF ratio of 9 orders of magnitude (Fig. 5). The gate voltage (VBG) was swept from -30 V to 30 V and the drain to source voltage (VD) was varied from 0.25 V to 0.75 V. The unipolar behavior can be tuned by fabricating two or more top gates. This will also reduce the additional hysteresis caused by using the buried oxide as a very thick gate dielectric.
Applications: The FLA-based silicidation process enables channel scaling. Devices based on this process show promising results and have potential applications as devices with reduced power consumption and low chip area [7]. These RFETs can also be used for the fabrication of power-efficient multi-independent gate-based logic circuits [8]. Moreover, the number of transistors and the chip area consumption can be reduced with the help of these transistors, preserving at the same time the functionality of the integrated circuits [9].
1.Heinzig, A. et al., Nano Lett., 2011.12(1):pp.119-124. 2.Simon, M. et al.,IEEE Trans Nanotechnol, 2017.16(5):pp.812-819.
3.Khan, B.M. et al., Appl. Sci. 2019. 9(17),3462. 4.Habicht, S. et al., Nanotechnology, 2010. 21(10): pp.105701.
5.Ogata, K. et al., Nanotechnology,2011.22(36):pp.365305. 6.Rebohle, L. et al., Semicond Sci Technol, 2016. 31(10): pp.103001.
7.Gaillardon, P.E. at al., in LATS, 2016, pp.195-200. 8.Rai, S. et al., IEEE Transactions VLSI, 2019.27(3):pp.560-572.
9.Raitza, M., et al., in DATE.2017,pp.338-343.

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  • Contribution to proceedings
    2020 Device Research Conference (DRC), 21.-24.06.2020, Columbus, OH, USA

Permalink: https://www.hzdr.de/publications/Publ-32236
Publ.-Id: 32236


Defect engineering in two-dimensional materials: from fundamentals to applications

Ghorbani Asl, M.

It is well known that defects have a remarkable influence on the properties of 2D materials, including optical, electrical, thermal, and mechanical properties. Irradiation with electron and ion beams allows precise control of defect generation by altering beam conditions and exposure dose. Although the response of bulk targets to ion irradiation has been extensively investigated, much less is known about the effects of ion bombardment on 2D materials.
We have studied the effects of ion irradiation on 2D materials by using analytical potential molecular dynamics combined with Monte Carlo simulations. In particular, we focused on the defect production mechanisms and characterized different types of defects in transition-metal dichalcogenides. The amount of damage in MoS2 by the impacts of noble gas clusters was explored for a wide range of energies and incident angles. It was found that the behavior of free-standing and supported 2D materials under the ion beam can be quite different, as the backscattered ions or atoms sputtered from the substrate can completely govern defect production. We showed that cluster irradiation can be used to produce uniform pores in 2D MoS2 with the diameter being dependent on cluster size and energy.6 Ion beam irradiations can also be used to displace sulfur atoms preferentially from either top or bottom layers of S atoms in MoS2 and also clean the surface from adsorbents. The possibility of changing defect concentrations or inducing local amorphization of a 2D material opens a path for tuning its physical properties via a combination of thermal treatment and a reactive vapor. These findings help to understand the fundamental physical mechanisms underlying ion irradiation of low-dimensional materials, which opens many opportunities for the beam-mediated engineering of the devices and nanomeshes for, e.g., DNA sequencing or molecule separation.

Keywords: two-dimensional materials; defects; ion irradiation; molecular dynamics simulations

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  • Invited lecture (Conferences) (Online presentation)
    IV Internatiol Symposium Modern Materials Science, 17.11.2020, Moscow, Russia

Permalink: https://www.hzdr.de/publications/Publ-32235
Publ.-Id: 32235


Resonant Tunneling and Hole Transport Behavior in Low Noise Silicon Tri-gate Junctionless Single Hole Transistor

Uddin, W.; Maity, S.; Dhyani, V.; Ahmad, G.; Georgiev, Y.; Das, S.

The fabrication of p-type silicon junctionless tri-gate transistors and their temperature dependent transport studies are reported in this work. The fabricated transistors have shown a good transfer characteristic down to a low temperature of ~ 80 K with an ON/OFF ratio of 106. The threshold voltage and the subthreshold slope were found to be dependent on temperature. In particular, the threshold voltage and the flat band voltage have positive slopes of 2.24 and 1.19 mV K−1, respectively, with temperature. Channel resistance was found to be increasing with decreasing temperature. The devices have shown a typical 1/f noise behavior in the frequency range of (1–50) Hz and 1/f2 type behavior in the frequency range of (50–100 Hz). At a temperature of 4.2 K, current vs. gate voltage characteristic at a fixed source drain bias shows clear coulomb peaks with different intervals for different gate bias voltages and the observed spikes were consistent within the sub-bands. We relate this to the single hole tunneling, mediated by the charged acceptors available in the channel region. Coupling strength of the dopants was also studied.

Keywords: Junctionless Nanowire Transistor; Temperature dependent Transport; Quantum transport; Coulomb diamonds

Permalink: https://www.hzdr.de/publications/Publ-32234
Publ.-Id: 32234


Negative resistance for colloids driven over two barriers in a microchannel

Erbe, A.; Leiderer, P.; Kreuter, C.

Video of superparamagnetic colloidal particles which are confined in a microchannel of 30µm width. The particles are driven into motion by tilting the microscope. Two barriers define an island in the channel, which causes an ordered region in the center of the channel. Transport through this island is observed as function of time and tilt angle.

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Permalink: https://www.hzdr.de/publications/Publ-32233
Publ.-Id: 32233


A Focused Ion Beam based in-situ cryo high resolution instrument for multimodal analysis in nano-biology

Hlawacek, G.; Barrahma, R.; Bouton, O.; Biesemeier, A.; Serralta Hurtado De Menezes, E.; Klingner, N.; de Castro, O.; Gnauck, P.; Lucas, F.; Duarte Pinto, S.; Wirtz, T.

Studying the interaction of nano-particles with biological tissue at the nanometer scale in a form as close as possible to the native wet environment is a key challenge in many nano-toxicological questions. The nanomaterial risk identification involves their physico-chemical characterization currently employing a variety of techniques and separate instruments. This makes the characterization an expensive and time-consuming process.
Here, we are developing a new integrated instrument for the ion beam based characterization of nanoparticles. The aim is to improve the efficiency of the nanomaterial characterization workflow by integrating several ion beam based techniques in one single instrument. The npSCOPE instrument is based on the well known Helium Ion Microscope technology [1] allowing the sample to be irradiated with very finely focused He + and Ne + ion beams at the nanometer-scale. Furthermore, the instrument incorporates detectors for secondary electron imaging, a secondary ion mass spectrometer (SIMS) for chemical analysis [2] and a detector allowing the detection of transmitted ions/atoms to obtain in-situ structural/3D visualisation data (STIM) [3]. The instrument will allow the characterization of nanoparticles in their native state as well as embedded in complex matrices (e.g. biological tissue, liquid, etc.). A further key feature of the instrument is cryo-capability, including a 5 axis cryo-stage, in order to perform analyses of biological samples in a frozen-hydrated state and thus avoid artefacts caused by classical sample preparation (e.g. chemical fixation) used for HV or UHV imaging of biological specimens at room temperature.
Here, we will present the instrument, report on the instrument’s performance and discuss the correlative microscopy capabilities. We will present first results obtained with the npSCOPE instrument on different kinds of nano-particle samples relevant in the field of nano-toxicology.
*
(For further information please visit www.npscope.eu)
[1] G. Hlawacek, A. Golzhä user (eds.), Helium Ion Microscopy (2016) Springer.
[2] T. Wirtz, O. De Castro, J.-N. Audinot, P. Philipp, Ann. Rev. Anal. Chem. 12 (2019).
[3] E. Serralta, Nico Klingner, Olivier De Castro, Michael Mousley, Santhana Eswara, Serge Duarte Pinto, Tom Wirtz, Gregor Hlawacek; Scanning transmission imaging in the helium ion microscope using a microchannel plate with a delay line detector, submitted to Beilstein Journal of Nanotechnology (2020).
This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 720964.

Keywords: HIM; STIM; npSCOPE

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  • Invited lecture (Conferences) (Online presentation)
    IAEA Technical Meeting on Imaging Using Ionizing Radiation to Address Biological Challenges, 30.11.-03.12.2020, Vienna, Österreich

Permalink: https://www.hzdr.de/publications/Publ-32232
Publ.-Id: 32232


Helium ion microscopy and its application to low fluence materials modification

Hlawacek, G.

Helium Ion Microscopy has become a standard imaging and nanofabrication technique in last decade. In my presentation I will introduce the technqiue and the underlying reasons for its exceptional capabilities. The latter include high lateral resolution, high depth of focus, ability to image insulating samples and exceptional nanofabrication capabilites. In the second part I will highlight selected applications of the method. This will include modification of 2D materials, magnetic materials and applications related to quantum technology. I will also allude on past and current developments in ion beam based analysis using the HIM.
[1] Hlawacek, G. & Gölzhäuser, A. (Eds.) Helium Ion Microscopy, Springer International Publishing, 2016.
[2] Hlawacek, G.; Veligura, V.; van Gastel, R. & Poelsema, B. Helium ion microscopy, J. Vac. Sci. Technol. B, 2014, 32, 020801

Keywords: HIM

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  • Lecture (Conference) (Online presentation)
    ŚRODOWISKOWE SEMINARIUM FIZYKI CIAŁA STAŁEGO, 04.11.2020, Krakau, Poland

Permalink: https://www.hzdr.de/publications/Publ-32231
Publ.-Id: 32231


Helium Ion Microscope based nanofabrication

Hlawacek, G.

Helium Ion Microscope based nanofabrication

Keywords: HIM; nanofabrication; GFIS

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  • Lecture (others) (Online presentation)
    Nanofabrication webinar series @ Master on Advanced Nanoscience and Nanotechnology, 23.04.2020, Barcelona, Spain
  • Lecture (others) (Online presentation)
    Webinar series on Advances Nanofabrication, 26.02.-9.4.2021, Barcelona, Spanien

Permalink: https://www.hzdr.de/publications/Publ-32230
Publ.-Id: 32230


Introduction to alpaka

Stephan, J.

This talk covers the alpaka parallel programming library as well as the surrounding ecosystem. It features an introduction to the alpaka programming model, a presentation of the ecosystem libraries cupla, Vikunja, LLAMA and bactria, and a glimpse into the future.

Keywords: alpaka; LLAMA; Vikunja; RedGrapes; cupla; C++; bactria; parallel programming; HPC; GPGPU

  • Open Access Logo Lecture (others) (Online presentation)
    HEP-CCE PPS weekly meeting, 29.01.2021, Batavia, Illinois, United States of America
  • Open Access Logo Lecture (others) (Online presentation)
    Compute Accelerator Forum, 12.05.2021, Genf, Schweiz
  • Open Access Logo Lecture (others) (Online presentation)
    FSP CMS Workshop 2021, 22.-24.09.2021, Genf, Schweiz

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Permalink: https://www.hzdr.de/publications/Publ-32229
Publ.-Id: 32229


Open-source PEM fuel cell model combining the unsaturated flow theory for porous media with Springer's model

Weber, N.; Knüpfer, L.; Zhang, S.; Reimer, U.; Beale, S.; M. Chaparro, A.; Ferreira-Aparicio, P.

The presentation gives an overview on a PEM fuel cell model developed within the framework of OpenFOAM. The capabilities of the model are demonstrated by simulating a conventional PEM fuel cell, which has been developed by CIEMAT. This cell is supplied by pure oxygen and hydrogen with a humidification of 100%, while operating at 80°C. The measured polarisation curve is reproduced by the OpenFOAM model quite well. Moreover, it allows to illustrate the current distribution, liquid water formation and the depletion of reactants within the porous electrodes. The model can easily be applied to other fuel cell geometries, thus helping in their design or operation.

  • Lecture (Conference)
    16th OpenFOAM Workshop 2021, 08.06.2021, Dublin, Irland

Permalink: https://www.hzdr.de/publications/Publ-32227
Publ.-Id: 32227


Igneous-metamorphic basement of Taquetr´en Range, patagonia, Argentina: A key locality for the reconstruction of the paleozoic evolution of patagonia

Renda, E. M.; González, P. D.; Vizán, H.; Oriolo, S.; Prezzi, C.; Ruiz González, V.; Schulz, B.; Krause, J.; Basei, M.

In this contribution, we present the stratigraphy of the igneous and metamorphic rocks of the Taquetr´en Range, a sector located in the southernmost margin of the North Patagonian Massif (42◦42′ 00′′ S - 69◦30′00′′ W). Its igneous and metamorphic basement is composed of the newly defined “Lagunita Salada Igneous-Metamorphic Complex” (LSIMC), “Paso del Sapo Plutonic Complex” (PSPC) and “Sierra de Taquetr´en Plutonic Complex” (STPC). The LSIMC comprises gneisses, schists, amphibolites and migmatites, which share a S1–S2 penetrative foliation with a mean orientation of 300◦–330◦/40◦–60◦ NE. Based on mineral paragenesis, metamorphic conditions of these rocks are the result of Barrovian-type metamorphism in the upper amphibolite to granulite facies. EPMA Th–U–Pb ages of monazites display two isochron main populations at 379 ± 5 Ma and 323 ± 5 Ma, which suggest long-term high-temperature conditions for the region between Late Devonian and Carboniferous times. The Complex is intruded by concordant tonalites, granodiorites, porphyric granites and minor pegmatites and felsic dykes, which are grouped in the PSPC. Both the LSIMC and PSPC are intruded by unfoliated peraluminous granitoids grouped in the STPC. Based on field and microstructural data, the pervasive foliation identified in the PSPC was caused by processes ranging from magmatic flow to solid-state deformation, indicating a syntectonic emplacement. Zircon U–Pb analysis by LA-ICP-MS in the PSPC shows two distinguishable groups with concordia ages of 314.1 ± 2.2 Ma and 302.8 ± 2.2 Ma, interpreted as the crystallization and subsequent deformation age respectively, related to protracted high-strain conditions. The outcrops in this area represent an almost full tectonic cycle encompassing from medium-high grade metamorphic rocks and syn-tectonic intrusions to posttectonic intrusions, therefore configuring a key locality for the analysis of North Patagonian Paleozoic evolution. Moreover, based on the compilation of U–Pb zircon ages, a ~20 My magmatic gap period (360-340 Ma) is recognized in the southwestern margin of the North Patagonian Massif coeval with amphibolite-granulite facies metamorphism in different sectors of the Central Patagonian Igneous-Metamorphic Belt, presenting thus important implications for the tectonic evolution of the area.

Keywords: Patagonia; Paleozoic; Igneous-metamorphic basement; U–Pb zircon; Th–U–Pb monazite

Permalink: https://www.hzdr.de/publications/Publ-32226
Publ.-Id: 32226


Mineralogical and geochemical constraints on the origin of the Sohland-Rožany Ni-Cu-(PGE) sulfide mineralization (Lausitz Block, Bohemian Massif, Germany/Czech Republic)

Járóka, T.; Staude, S.; Seifert, T.; Pfänder, J. A.; Bauer, M. E.; Krause, J.; Schulz, B.

The Sohland-Rožany Ni-Cu-(PGE) sulfide mineralization is hosted by a small gabbroic dike that is one of several Ni-Cu sulfide-bearing gabbroic intrusions in the northern Bohemian Massif. The intrusions are associated with a Middle Devonian to Early Carboniferous mafic-ultramafic plumbing system that emplaced within Cadomian granodiorites of the Lausitz Block. The Sohland-Rožany dike comprises varitextured olivine- and hornblende bearing gabbro and hornblende gabbro, with in particular the olivine-bearing lithologies affected by late-stage hydrothermal alteration. The variable lithotypes originated from differently fractionated magma batches. Fractionation likely took place in deeper parts of the magmatic systems, e.g. within staging magma chambers.
Mineralogical features like Ti-rich primary brown hornblende and diopsidic clinopyroxene as well as overall enriched incompatible element contents suggest moderate alkaline basaltic parental magmas with high volatile contents. The magmatic sulfide mineralization is exclusively hosted by the olivine- and hornblende-bearing gabbro and include disseminated, net-textured and massive sulfides. The mineralization types are predominated by pyrrhotitepentlandite-chalcopyrite assemblages accompanied by secondary violarite and pyrite as well as by accessory Pt, Pd, Au and Ag phases. The disseminated and net-textured sulfides have highly variable modal proportions of base metal sulfides with pyrrhotite-dominated beside chalcopyrite-dominated aggregates on the hand specimen scale. The platinum-group mineral (PGM) assemblage includes Pd-Pt-Ni-bearing bismuthotellurides of the melonite– merenskyite and michenerite–testibiopalladite solid solution series as well as sperrylite, of which bismuthian palladian melonite represents the most prominent PGE-bearing phase. The sulfide ores feature evolved Ni and highly variable Cu and Pt, Pd and Au tenors (3.5–7.5 wt.% Ni, 0.1–16.6 wt.% Cu, 80–3080 ppb Pt, 70–5320 ppb Pd and 20–3770 ppb Au). The magmatic sulfides are locally characterized by a late-stage hydrothermal overprint where sulfides were replaced by hydrous secondary phases (e.g. actinolite–tremolite and chlorite). A significant redistribution of the PGE due to hydrothermal alteration is unlikely as the majority of PGM show a close spatial association to the base-metal sulfides.
Textures and chemical compositions of the sulfides suggest that repeated magma batches eroded already fractionated sulfide pools and entrained early crystalized cumulates of monosulfide solid solution (MSS) together with variable fractionated sulfide melts. Sulfide saturation in the Sohland-Rožany magmas was likely controlled by fractional crystallization and assimilation of the granodioritic wall-rock in the course of thermomechanical erosion. The latter process was amplified by high mica contents of the granodiorites. Sulfur isotope signatures (–2.0 to – 1.2 ‰ VCDT) and the S-poor nature of the hosting granodiorites exclude a significant contribution of S from the country rocks.

Keywords: Gabbro; Lausitz Block; magmatic Ni-Cu-PGE sulfides; thermomechanical erosion; melonite

Permalink: https://www.hzdr.de/publications/Publ-32225
Publ.-Id: 32225


Develop common input and output standards for PIC-codes

Debus, A.; Bertini, D.; Quere, F.; Vincenti, H.; Horny, V.; Vieira, J.

JRA PRISES, Task 2.5: Development of common input/output standards of Particle-In-Cell (PIC) codes and associated in-situ and post-processing tools, Status report

  • Lecture (others) (Online presentation)
    LASERLAB 5 - JRA progress meetings, 18.11.2020, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32224
Publ.-Id: 32224


Vertical Zoning in Hydrothermal U-Ag-Bi-Co-Ni-As Systems – A Case Study from the Annaberg-Buchholz District, Erzgebirge (Germany)

Guilcher, M.; Schmaucks, A.; Krause, J.; Markl, G.; Gutzmer, J.; Burisch-Hassel, M.

The Annaberg-Buchholz district is a classic occurrence of hydrothermal five-element (U-Ag-Bi-Co-Ni-As) veins in the Erzgebirge (Germany) with a historical production of ~8700 t of Co ore, 496 t of U ore and 26.9 t of Ag. Multiple mineralization stages are recognized in polyphase veins hosted by Proterozoic paragneiss. Fluorite-barite-Pb-Zn mineralization occurs across the entire vertical profile of the district, whereas U and five-element stages are restricted to the upper 400 m below surface, coinciding with a graphite-rich gneiss lithology.
Here, we present field and petrographic observations, electron probe microanalysis and fluid inclusion data, as well as thermodynamic calculations to characterize fiveelement and fluorite-barite-Pb-Zn associations, and to constrain the origin of the vertical zoning in the Annaberg-Buchholz district. Microthermometric analyses of fluid inclusions related to the fluorite-barite-Pb-Zn stage yield homogenization temperatures between 78 and 140°C and salinities between 21.9 and 27.7 % eq. w(NaCl-CaCl 2 ).
A correlation of fluid inclusion Na/(Na+Ca) ratios with salinity suggests fluid mixing as a likely precipitation mechanism and relates ore-formation tentatively to regional tectonics of the Mesozoic opening of the Atlantic.Thermodynamic calculations indicate that U is more sensitive to reduction than As,
predicting that arsenide minerals are precipitated more distally relative to uraninite upon reduction along the fluid flow path. This implies that the observed vertical zoning is not a primary feature but is the result of hydrothermal remobilization. The observations made in the Annaberg-Buchholz district have general importance to the understanding of U-rich five-element mineralization and may be relevant for exploration targeting in unconformity-related U deposits.

Permalink: https://www.hzdr.de/publications/Publ-32223
Publ.-Id: 32223


Electron probe petrochronology of polymetamorphic garnet micaschists in the lower nappe units of the Austroalpine Saualpe basement (Carinthia, Austria)

Schulz, B.; Krause, J.

Polymetamorphic garnet micaschists from the parautochthonous Kliening and the overlying Preims units in the lower part of the Austroalpine Saualpe basement in Carinthia (Austria, Eastern Alps) display complex microstructural and mineral-chemical relationships. Electron-beam based automated routines with EDX spectral mapping, WDS element mapping and manual WDS element analysis were applied for garnet mineral-chemical characterisation and monazite chemical dating. Two garnet porphyroblast generations and diverse monazite age populations have been revealed in low-Ca and high-Al-metapelites. Garnet 1 in both Kliening and Preims units has decreasing Mn, constant Ca and significantly increasing Mg from cores to rims. Geothermobarometry of garnet 1 assemblages signals a crystallization along a M1 prograde metamorphism culminating at 550 - 670 °C/7 - 8 kbar. In the Preims Unit a subsequent pervasive 300 - 250 Ma high-Y and high-Gd monazite 1 crystallisation coincides with the intrusion of Permian and Early Triassic pegmatites. In the Kliening Unit where pegmatites are lacking, no Permian monazites are observed. Coronas of apatite and allanite around the large Permian monazites in the Preims Unit signal a retrogressive stage. A M2 event with garnet 2 postdates the corona formation around Permian monazites. Garnet 2 displays always low Mn at high Ca and Mg, with increasing and then decreasing XCa at decreasing and then increasing XMg. The garnet 2 assemblages recorded a prograde P-T evolution at a high P/Tgradient, from 550 °C/8 kbar to 700 °C/10 - 13 kbar in the Kliening Unit, and from 600 °C/6 - 10 kbar to 700 °C/14 - 15 kbar in the Preims Unit. Monazite 2 populations with ages from 100 - 85 Ma and with lower Y and Gd contents crystallized at decreasing pressure subsequent to garnet 2, indicating a Cretaceous (Eo-Alpine) age for the metamorphic event M2. In the histogram view, the monazite age pattern in the Preims Unit and the overlying Saualpe Eclogite Unit are quite similar with Permian and Cretaceous age maxima. When regarding the considerable differences of peak pressures during the M2 event, a major tectonic discontinuity can be stated between these units. The Saualpe nappe units underwent two distinct clockwise metamorphic cycles at Carboniferous - Early Permian and then Cretaceous periods, related to continental collisions under different P-T regimes. This led to a characteristic distribution pattern of monazite ages in these units which is different from other Austroalpine basement areas.

Keywords: garnet micaschists; monazite; corona structures; polyphase metamorphism; Austroalpine basement; Permian; Cretaceous

Permalink: https://www.hzdr.de/publications/Publ-32222
Publ.-Id: 32222


Feldspar recycling across magma mush bodies during the voluminous Half Dome and Cathedral Peak stages of the Tuolumne intrusive complex, Yosemite National Park, California, USA

Oppenheim, L. F.; Memeti, V.; Barnes, C. G.; Chambers, M.; Krause, J.; Esposito, R.

Incremental pluton growth can produce sheeted complexes with no magma-magma interaction or large, dynamic magma bodies communicating via crystal and melt exchanges, depending on pulse size and frequency of intrusions. Determining the degree and spatial extent of crystal-melt exchange along and away from plutonic contacts at or near the emplacement level, such as in the large, long-lived Tuolumne intrusive complex (TIC) in California, sheds light onto the process and evolution of incremental growth.
This study used field mapping and petrographic and geochemical analysis of plagioclase and K-feldspar populations in the equigranular Half Dome (eHD), porphyritic Half Dome (pHD), and Cathedral Peak (CP) Granodiorites of the southeastern section of the TIC to determine the presence and/or extent of feldspar recycling at interunit contacts. Our results suggest that contacts between major units are predominantly ~400-m- to 3-km-thick gradational zones. K-feldspar is compositionally distinct in eHD and neighboring gradational zones and shows no evidence of mixing. K-feldspar in a gradational zone between pHD and CP shows evidence of mixing between the two. Plagioclase in eHD and CP display distinct ranges of anorthite content, Sr, and light rare earth element abundances; both populations are observed in pHD. Major oxide and trace element calculations of melts in equilibrium with plagioclase cores indicate that the melts were more silicic, less calcic, and lower in Sr and Rb than corresponding analyzed whole-rock samples. These results suggest that the magmas also underwent plagioclase and biotite accumulation. The presence of two plagioclase populations in pHD is consistent with eHD and CP hybridizing to form pHD in an increasingly maturing and exchanging TIC magmatic system during the eHD-pHD-CP stages but before groundmass and small K-feldspar phenocrysts crystallized.

Permalink: https://www.hzdr.de/publications/Publ-32221
Publ.-Id: 32221


Erzlabor - we visualize value!

Bachmann, K.

Dieser Beitrag stellt Erzlabor, ein Spin-Off des HZDR, den Partnern des EIT RawMaterials in Europa vor.

  • Invited lecture (Conferences) (Online presentation)
    EIT Brokerage Event, 26.11.2020, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32220
Publ.-Id: 32220


We visualize value!

Bachmann, K.

Dieser Beitrag stellt Erzlabor, ein Spin-Off des HZDR, den Transferassistenten aus Sachsen vor.

  • Lecture (others)
    IHK-Transferfrühstück, 30.09.2020, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32219
Publ.-Id: 32219


Comparison of partial roasting and alkaline sulfide leaching for treatment of As-rich concentrates

Meiner, K.; Weigelt, A.; Charitos, A.; Stelter, M.; Wrobel, M.; Förster, K.; Hammerschmidt, J.; Parra, R.; Bachmann, K.; Buchmann, M.

Copper possesses a variety of applications. With regard to the primary copper production, enriched sulfidic copper concentrates are fed to the smelters. Within the last decades the copper concentration in usable ores/concentrates is decreasing. Concentrate content in impurities like arsenic, antimony, bismuth and other hazardous elements, which are mineralogically bonded, is on the rise. In addition to the state of the art partial roasting process, the removal of arsenic through alkaline sulfide leaching of respective copper concentrates is a viable option. Mineralogical and chemical compositions of arsenic-bearing concentrates are measured by PXRD, XRF and AES. The particle based mineralogy of examine concentrates is characterized by MLA. Moreover, fluid bed roasting and under nitrogen/oxygen atmosphere are conducted to examine operational parameters on arsenic removal with focus on the oxygen partial pressure. For the hydrometallurgical part leaching tests with a sulfide solution under alkaline conditions are conducted in a lab scale reactor allowing for direct process comparison.

  • Contribution to proceedings
    EMC 2021 - European Metallurgical Conference, 27.-30.06.2021, Salzburg, Austria

Permalink: https://www.hzdr.de/publications/Publ-32218
Publ.-Id: 32218


Geometallurgical Characterization of Tailing Storage Facilities

Bachmann, K.

This presentations shows novel analytical methods and geometallurgical modelling techniques for re-mining of tailing storage facilities.

  • Invited lecture (Conferences) (Online presentation)
    Online-Workshop: Re-mining de residuos, 15.12.2020, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32217
Publ.-Id: 32217


Vom Erz zum Metall – Innovative Materialcharakterisierung durch Automatisierte Mineralogie

Bachmann, K.

‚Automatisierte Mineralogie‘ bezeichnet eine analytische Untersuchungsmethode auf Basis einer Kombination von Rasterelektronenmikroskopie (REM) und energiedispersiver Röntgenspektroskopie (EDS). Automatisierte mineralogische Untersuchungen bieten die einzigartige Möglichkeit quantitative Daten einer Vielzahl von Parametern aufzustellen, die für die Entwicklung und kritische Bewertung von Aufbereitungstests greifbar sind. Diese Parameter umfassen den modalen Mineralbestand, den kalkulierten Elementgehalt, Elementverteilungen, Mineralassoziationen, Größenverteilungen von Partikeln und Mineralkörnern, Partikeldichteverteilungen sowie die Mineralfreisetzung. Aus den Analysedaten können auch Proben-Übersichtsbilder (‚Mineralkarten‘) und Bilder bestimmter Mineralgruppen extrahiert werden.
Die Möglichkeiten werden anhand von zwei Beispielen verdeutlicht. Zum Einen wurde sogenannte Schwarzmasse charakterisiert, ein sekundärer Rohstoff, welche beim Recycling von Li-Ionenbatterien entsteht. Zum Anderen, geht es um primäre Lagerstätten, hier die Gewinnung von Platingruppenelementen in einer Chromitlagerstätte in Südafrika.

  • Invited lecture (Conferences) (Online presentation)
    FA-Lagerstätten GDMB, 14.05.2020, Freiberg, Detschland

Permalink: https://www.hzdr.de/publications/Publ-32216
Publ.-Id: 32216


Charakterisierung von Lithium-Ionen-Batterien (LIB) in Recyclingprozessen und Abschätzung der Aufschlusseffizienz von Elektroden mithilfe automatisierter Mineralogie

Bachmann, K.; Vanderbruggen, A.; Hayagan, N. L.; Rudolph, M.

Lithium-Ionen-Batterien (LIBs) gehören zu den derzeit wichtigsten elektrochemischen Energiespeichersystemen für elektronische Mobilgeräte und Elektrofahrzeuge. Die wachsende weltweite Nachfrage nach LIBs, geht mit einer Erhöhung des Bedarfs an Co, Mn, Ni, Li und Graphit einher. Diese Erhöhung der Nachfrage dieser Rohstoffe stellt eine besondere Herausforderung für den schon jetzt angespannten weltweiten Rohstoffmarkt dar, verbunden mit Versorgungsrisiken, Preisschwankungen und Marktmonopolen. Tatsächlich sind Co und natürlicher Graphit in Europa seit 2010 als kritische Rohstoffe (CRM) geführt, Li sowie Mn befinden sich an der Grenze der Kritikalität. Um potenziell die Kluft zwischen Angebot und Nachfrage zu verringern sowie die europäischen Nachhaltigkeitsziele zu erreichen, hat das Recycling von Lithium-Ionen-Batterien (LIB) hat in den letzten Jahren viel Aufmerksamkeit auf sich gezogen. Hierbei wird sich hauptsächlich auf die wertvollen Metalle wie Kobalt, Nickel und Lithium konzentriert. Allerdings gehen während des Recyclingprozesses erhebliche Mengen anderer Komponenten wie Elektrolyt, Separator oder Graphit verloren. So kann Graphit zum Beispiel während der pyrometallurgischen Behandlung entweder abgeschlackt oder als Reduktionsmittel verbraucht werden. Darüber hinaus gehen einige andere wertvolle Metalle wie Co in den Grobfraktionen durch einen zu geringen Aufschlussgrad an die Berge verloren. Aus diesem Grund müssen neue und umfassende LIB-Recyclingverfahren gefunden werden.
In dieser Studie werden zur Freisetzung von aktiven Materialien aus Elektroden sowohl eine mechanische als auch thermo-mechanische Recyclingprozessroute angewendet. Dabei wird neben den werthaltigen Metallen insbesondere die Rückgewinnung von Graphit in den Fokus gestellt. Die mechanische Route arbeitet mit einem Schlagscherbrecher, während für die thermo-mechanischen Versuche die Batterien vor dem Zerkleinern bei 500-650 °C vakuumpyrolysiert wurden. Die sogenannte Schwarzmasse-Fraktion kleiner als 1 mm wurde abgetrennt und basierend auf der Partikelgrößenverteilung in 4 Größenfraktionen klassifiziert. Eine genaue Charakterisierung sowohl der Hauptchemie als auch eine detaillierte Charakterisierung der enthaltenen Phasen im recycelten Materials stellt nach wie vor eine große Herausforderung dar. Deshalb wurde jede Fraktion wurde durch verschiedene analytische Methoden charakterisiert, einschließlich Röntgenfluoreszenz (XRF), Röntgenbeugung (XRD), Atomabsorptionsspektrometrie (AAS). Für eine gute Visualisierung und Quantifizierung der Ergebnisse des Aufbereitungserfolgs und Prozesseffizienz ist eine detailliertere analytische Charakterisierung erforderlich. Diese Studie schlägt eine innovative und neuartige neue Charakterisierungsmethode vor, die auf automatisierter Mineralogie basiert. Dabei werden verschiedene wichtige Partikelparameter wie Größe, Zusammensetzung und Verwachsung analysiert und quantitativ ausgewertet. Das für die Messungen genutzte Mineral Liberation Analyzer (MLA) System nutzt eine Kombination aus Rasterelektronenmikroskopie (REM) -Bildanalyse und energie-dispersiver Röntgenspektroskopie (EDS) und ist im primären Rohstoffsektor als leistungsstarke Methode etabliert. Allerdings fehlen für den Einsatz im sekundären Rohstoffsektor dezidierte Datenbanken, um die Partikel der Schwarzmasse schnell und präzise analysieren zu können. Eine analytische Herausforderung dieser Studie ist es demnach auch eine Datenbank zur Batteriecharakterisierung zu erstellen und für breite Anwendungsbereiche einsetzen zu können.
Im Ergebnis zeigt die hier vorgestellte Studie, dass bei den angewendeten Zerkleinerungsverfahren eine Freisetzungsselektivität der Elektrodenfolien beobachtet werden konnte. Der thermo-mechanische Prozess setzt dabei mehr aktive Partikel aus den Folien frei als ein mechanischer Prozess allein. Infolgedessen sind insbesondere bei thermo-mechanisch zerkleinerten Proben die meisten Graphitpartikel in der <63 um-Fraktion konzentriert. Cu-Folien werden generell besser aufgeschlossen als Al-Folien. Es wurde jedoch festgestellt, dass der Prozesstyp unterschiedliche Auswirkungen auf die Freisetzung von Al-Folie hat. Der thermomechanische Prozess setzt mehr Metalloxide aus der Al-Folie frei als nur der mechanische Prozess. Der Al-Bruch wird jedoch stärker durch die Wärmebehandlung beeinflusst, wodurch feinere Al-Partikel entstehen, die für weitere hydrometallurgische Wege problematisch sein können.

  • Poster (Online presentation)
    Aufbereitung und Recycling, 12.-13.11.2020, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32215
Publ.-Id: 32215


Characterization of lithium-ion batteries in recycling processes and assessment of the liberation efficiency of black mass components using automated mineralogy

Bachmann, K.; Vanderbruggen, A.; Hayagan, N. L.; Rudolph, M.

Lithium-ion batteries (LIBs) are currently the most important electrochemical energy storage sys-tems for electronic mobile devices and electric vehicles. The growing global demand for LIBs is accompanied by an increase in the need for Co, Mn, Ni, Li and graphite. In order to narrow the gap between supply and demand and to achieve the European sustainability goals, the recycling of LiBs has attracted a lot of attention in recent years. Here, the focus is on valuable metals such as cobalt, nickel and lithium as well as graphite. In addition, due to its chemical and phase compositions, the battery material remains to be a huge challenge for a proper materials characterization. Hence, there is not only a need to find innovative and comprehensive LiB recycling process solutions but also to develop new analytical workflows to enhance the understanding of the battery material.
In this study, LIBs are fed to a mechanical and thermo-mechanical recycling process route to release active materials from electrodes foils. In addition to the valuable metals, the focus is particularly on the recovery of graphite. The mechanical route works with an impact shear crusher, while for the thermo-mechanical tests the batteries were vacuum pyrolyzed at 500-650 °C before crushing. The so-called black mass fraction smaller than 1 mm was separated and further classified into four size fractions. Accurate characterization of both the main chemistry and detailed characterization of the phases contained in the recycled material remains a major challenge. Therefore, each fraction has been characterized by different analytical methods, including X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES). For a good visualization and quantifica-tion of the results of the processing success and process efficiency, a more detailed analytical char-acterization is required. This study proposes an innovative and novel characterization method based on automated mineralogy. Various important particle parameters such as size, composition and ad-hesion are analyzed and quantitatively evaluated. The Mineral Liberation Analyzer (MLA) system used for the measurements uses a combination of scanning electron microscopy (SEM) image analy-sis and energy-dispersive X-ray spectroscopy (EDS) and is established as a powerful method in the primary raw materials sector. However, there are no dedicated databases for use in the secondary raw materials sector in order to analyze black mass material in a fast and precise manner. An analyti-cal challenge of this study is therefore to create a database for battery characterization and to be able to use it for a wide range of applications.
Results of this study display a selective liberation of electrode foils during the beneficiation process. The thermo-mechanical process releases more active particles from the foils than a mechanical pro-cess alone. Hence, most of the graphite particles are liberated and concentrated in the < 63 μm frac-tion, in particular in the case of thermo-mechanically treated samples. Cu foils are generally better liberated than aluminium foils. However, it was found that the process type has different effects on Al foil liberation. The thermomechanical process liberates more metal oxides from the Al foil than the mechanical process alone but Al breakage is more affected by thermal treatment, resulting in finer Al particles.

Keywords: Black mass; MLA; XRF; ICP-OES; Spent Lithium Ion Battery

  • Contribution to proceedings
    EMC 2021 - European Metallurgical Conference, 27.-30.06.2021, Salzburg, Austria

Permalink: https://www.hzdr.de/publications/Publ-32213
Publ.-Id: 32213


Prädiktive Geometallurgie in Freiberg – von „Virtual Twins“ und Prozessoptimierung

Bachmann, K.; Pereira, L.; Tolosana Delgado, R.; van den Boogaart, K. G.; Gutzmer, J.

Der moderne Bergbausektor steht vor gewaltigen technischen Herausforderungen. Dazu zählen der Rückgang von Erzgehalten, der zunehmende Umgang mit komplexen Mineralparagenesen und sehr feinen Korngrößen aber auch einer steigenden Erzvariabilität. Mit Hilfe geometallurgischer Modelle versucht die Bergbauindustrie diese Herausforderungen zu bewältigen und das Verhalten des Erzes während des Abbaus, der Aufbereitung und der Verhüttung quantitativ vorherzusagen. Um hier einen Beitrag zu leisten, wird am Standort Freiberg seit 2008 geometallurgische Kernkompetenz aufgebaut. Diese Entwicklung wurde mit der Gründung des Helmholtz-Instituts Freiberg für Ressourcentechnologie (HIF), einer gemeinsamen Gründung des Helmholtz-Zentrums Dresden-Rossendorf (HZDR) und der TU Bergakademie Freiberg (TU Bergakademie Freiberg) im Jahr 2011, stark beschleunigt. Aus diesem Grund zählt Freiberg heute weltweit zu den wichtigsten Forschungs- und Entwicklungsstandorten der Geometallurgie. In diesem Artikel werfen wir einen Blick auf den aktuellen Stand der Entwicklungen, mit Fokus auf zwei sehr erfolgreiche Projekte im Bereich der geometallurgischen Modellierung, sowohl primärer als auch sekundärer Rohstoffe.

  • Open Access Logo ACAMONTA 27(2020), 22-26

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Permalink: https://www.hzdr.de/publications/Publ-32212
Publ.-Id: 32212


Experimental observation of elevated heating in dynamically compressed CHfoam

Falk, K.; Fontes, C. J.; Fryer, C. L.; Greeff, C. W.; Holec, M.; Johns, H. M.; Montgomery, D. S.; Schmidt, D. W.; Smid, M.

We present an experimental result of significantly increased heating in a laser-driven blastwaveexperiment carried out at the OMEGA laser facility. Abnormally high temperatures wereobserved in warm dense CH compared to older experiments and theoretical predictions. Thehigher temperatures in compressed CH were linked to an improved smoothness of the laserintensity profile, which resulted in better efficiency of the drive and coupling of more energyinto the system compared to previous similar experiments. Fifteen beams with combinedintensity of∼7×1014W cm−2and a square intensity profile with 2 ns duration were used todrive a strong shock, which subsequently developed to a blastwave travelling through lowdensity CH foam creating warm dense matter. Multiple diagnostics were used to examine thethermodynamic conditions in the warm dense CH foam. Velocity interferometry (VISAR) andstreaked pyrometry (SOP) observed increased blastwave velocities, while x-ray Thomsonscattering (XRTS) measured elevated temperatures of 17.5−35 eV in compressed CH foam.The experimental results were compared to hydrodynamic simulations and a potentialcontribution from x-rays to the elevated temperatures in the dense material was considered.

Permalink: https://www.hzdr.de/publications/Publ-32211
Publ.-Id: 32211


Dataset for: Flow morphologies in straight and bent horizontal pipes

Döß, A.; Schubert, M.; Wiedemann, P.; Schleicher, E.; Hampel, U.

This data set contains gas phase fraction data (void files, v.) obtained from wire-mesh sensor recordings up and downstream of horizontal pipe bends. The test sections and experimental setups are explained in the correpsonding journal paper.

The post processing was done with the Wire-mesh Sensor Framework GUI (Version 1.3.0).

The archive is organzed as follows:
(1) Each .zip file contains the void files for one distinct location (INL, OUT or REF) for the respective test sections (S - straight pipe, B - Horizontal 90° Bend, Upr_SB - Upright S-bend, Hor_SB - Horizontal S-bend)  and pipe diameter (DN50 and DN200).

(2) The 'overview.csv' (separator = semicolon, decimal operator: = comma) links the files in this data set to the corresponding flow rates, FFPI degrees of membership and RGB color values as they are presented in the journal paper. The column 'File Prefix' contains the explicit file indicator for the .v-files, the column 'Direcotry' contains the location of in this data set.

(3) The MatLab script  'openvoid.m' exemplarily shows how to read in the data contained in the .v file.

Keywords: Flow morphologies; Horizontal Two-phase flow; Wire-mesh sensor; TERESA

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Permalink: https://www.hzdr.de/publications/Publ-32210
Publ.-Id: 32210


Convection in Liquid Metal Batteries - Comparing Results from OpenFOAM, Semtex and SFEMaNS

Personnettaz, P.; Klopper, T. S.; Benard, S.; Weber, N.; Weier, T.

Switching the energy supply from today’s dominant fossil sources to mainly variable renewable energies (wind and solar) means a fundamental change. It will entail the transformation from a centralised energy system to distributed generation that needs flexibility options to balance supply and demand across time and space. Transmission grid expansions can only partially account for the resulting variations in supply. Therefore, large-scale stationary storage will gain importance in future energy landscapes.

Among the candidates to meet the growing demand for stationary storage are liquid metal batteries (LMBs). Their active materials as well as the electrolyte are in the liquid state. The cell interior consists of two layers of liquid metals interspaced by a molten salt electrolyte in stable density stratification. This conceptually very simple and self-assembling structure has the unique advantage to allow for an easy scale-up at the cell level: single-cell cross sections can potentially reach several square-meters. Such cell sizes enable highly favourable and otherwise unattainable ratios of active to construction material because of the cubic scaling (volume) of the former and the quadratic scaling (surface) of the latter. The total costs should therefore largely be determined by those of the active materials. While mass transport in most modern battery systems is typically dominated by diffusion and migration in micrometer-scale liquid layers and solids, convection - with exception of redox-flow batteries - rarely plays a role. This is in stark contrast to LMBs were mediated by the fully liquid interior fluid flow can be driven by various mechanisms and has a strong influence on cell performance and operational safety. Electric currents, magnetic fields, and heat and mass transfer are tightly coupled with the cells’ electrochemistry.

The talk will focus on the influence of solutal convection in the positive electrode on the cycling behaviour of a cell. We consider a Li-Bi battery, a cell chemistry for that ample experimental material is available in the literature. While this is true for the electrochemical characteristics, detailed experimental information on the flow in these batteries is largely missing. To compensate at least partially for this deficiency, we employ three different codes and compare their results. In the discharged state, the positive electrode consists of a Li(Bi) alloy. When charging the cell, low density Li is removed from the top of the positive electrode. This increases locally the density of the alloy and Li-depleted fluid starts to sink down in plumes. Rapidly, solutal convection drives a flow in the whole cathode and intensely mixes the remaining alloy. While stabilising thermal gradients can occur, densities of the positive electrode’s metal (Bi in our case) are typically an order of magnitude larger than the negative electrode metal (Li here) ones. In comparison, thermal expansion coefficients are quite small and due to the good thermal conductivity of metals, temperature differences tend to be smoothed out quickly. Thus, compositional (i.e. solutal) gradients should dominate over thermal ones and constitute the primary cause or inhibitor of motion in the positive electrode.

The OpenFOAM solver is based on buoyantBoussinesqPimpleFOAM extended by the concentration convection- diffusion equation and by a variable density depending on temperature as well as composition. Mass transfer through the electrolyte-positive electrode interface is captured by an electrochemically consistent mass flux boundary condition.

Onset of solutal convection from an initially well mixed state is studied in 2D for different charging currents. The results are compared to computations done with the spectral element solver Semtex and with the mixed spectral and finite element code SFEMaNS. Both programs are available under the GNU General Public License. While different onset times are to be expected due to the various numerical approaches, growth rates obtained with all three solver match very well. Development of the plumes that are the immediate consequences of the instability is quite consistent across the codes, as well as the formation of larger vortical structures at later stages.

Computations in 3D allow for a more realistic description of the flow and a better understanding of mixing. Due to the limited computational resources available to us we undertook these investigations with the more specialised and fast code Semtex only. Even with this code, care had to be taken to sufficiently resolve the fine plume structures in the early phases of flow development especially near the cells rim.

Properly capturing flow development and mixing in the positive electrode of a typical liquid metal battery allows for a correct description of the cell’s cycling behaviour.

Keywords: Liquid metal batteries; energy storage; solutal convection

  • Open Access Logo Lecture (Conference) (Online presentation)
    16th OpenFOAM Workshop 2021, 08.-11.06.2021, Dublin, Irland

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Permalink: https://www.hzdr.de/publications/Publ-32209
Publ.-Id: 32209


FineFuture: First results in innovative fine-particle flotation

Dirlich, S.

The H2020 Project FineFuture aims at the improvement of the recovery of (ultra) fine particles from primary and secondary resources. Having reached the halftime of the project first results are available, and demonstrate that the proposed advances in the recovery of critical raw materials can be achieved.

Keywords: fine particles; flotation; froth flotation; bubble-particle collision; CFD modelling; critical raw materials

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    PROMETIA Annual Scientific Seminar, 10.12.2020, Paris, Frankreich

Permalink: https://www.hzdr.de/publications/Publ-32208
Publ.-Id: 32208


Sanierung und Umbau eines Wohnhauses der 1930er Jahre

Schweiker, K.; Dirlich, S.

Das Wohnhaus Wieckestraße Nr. 10 in Dresden ist fast 100 Jahre alt und eines der letzten original erhaltenen Gebäude in der Doppelhaus-Siedlung in Leubnitz-Neuostra. Es steht nicht unter Denkmalschutz. Anliegen ist es, möglichst viel originale Substanz zu erhalten und das Gebäude nachhaltig, ökologisch und der Substanz angemessen zu sanieren und umzubauen. Dabei ist es eine Herausforderung, bei nahezu gleichbleibender Kubatur des kleinen Hauses sowohl mehr Raum, Licht und Großzügigkeit zu schaffen als auch eine gute Balance zwischen denkmalgerechter Sanierung und energetischer Ertüchtigung herzustellen. Ziel ist es, die Förderstufe des KfW-Effizienzhauses 115 zu erreichen. Die Sanierung hat im Juni 2020 begonnen, Fertigstellung und Einzug sind für Dezember 2020 geplant. Trotz vollberuflicher Einbindung erbringen die Bauleute wertvolle Eigenleistungen. Zur Unterstützung und Förderung eines möglichst reibungslosen Ablaufes, für gut funktionierende Abstimmungen, eine wertschätzende Kommunikation, gegenseitigen Respekt und Vertrauen sind vor Baubeginn durch die Architektin, die auch als Dialogprozess-Begleiterin ausgebildet ist, dialogische Kompetenzen und der Dialog als Methode und Übungsform vorgestellt worden. Die bisherige Resonanz ist sehr positiv.

Keywords: sustainable building; resource efficiency; restoration; historic building; retrofit

  • Book chapter
    Weller, Bernhard; Scheuring, Leonie: Denkmal und Energie 2021 - Energieeffizienz, Nachhaltigkeit und Nutzerkomfort, Wiesbaden: Springer Vieweg, 2021, 978-3-658-32248-9, 129-146

Permalink: https://www.hzdr.de/publications/Publ-32207
Publ.-Id: 32207


Molecular-level speciation of Eu(III) adsorbed on a migmatized gneiss as determined using µTRLFS

Molodtsov, K.; Demnitz, M.; Schymura, S.; Jankovský, F.; Havlová, V.; Schmidt, M.

The interaction of Eu(III) with thin sections of migmatised gneiss from the Bukov Underground Research Facility (URF), CZ was characterized by microfocus time-resolved laser-induced luminescence spectroscopy (µTRLFS) with a spatial resolution of ~20 µm, well below typical grain sizes of the material. By this approach, sorption processes can be characterized on the molecular level while maintaining the relationship of the speciation with mineralogy and topography. The sample mineralogy was characterized by powder X-ray diffraction and Raman microscopy and the sorption was independently quantified by autoradiography using Eu-152. Representative µTRLFS studies over large areas of multiple mm2 reveal that sorption on the heterogeneous material is not dominated by any of the typical major constituent minerals (quartz, feldspar, and mica). Instead, minor phases such as chlorite and prehnite control the Eu(III) distribution, despite their low contribution to the overall composition of the material, as well as common but less studied phases like Mg-hornblende. Especially prehnite shows high a sorption uptake as well as strong binding of Eu to the mineral surface. Sorption on prehnite and hornblende happens at the expense of feldspar, which showed the highest sorption uptake in a previous spatially-resolved study on granitic rock. Similarly, sorption on quartz is reduced, even though only low quantities of strongly bound Eu(III) were found here previously. Our results illustrate how competition of mineral surfaces for adsorbing cations drives metal distribution in heterogeneous systems.

Keywords: µTRLFS; Luminescence spectroscopy; Microscopy; Crystalline rock; Radionuclide migration; Prehnite; Sorption

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Permalink: https://www.hzdr.de/publications/Publ-32206
Publ.-Id: 32206


Drop Size Dependence of the Apparent Surface Tension of Aqueous Solutions in Hexane Vapor as Studied by Drop Profile Analysis Tensiometry

Fainerman, V. B.; Kovalchuk, V. I.; Aksenenko, E. V.; Sharipova, A. A.; Liggieri, L.; Javadi, A.; Makievski, A. V.; Nikolenko, M. V.; Aidarova, S. B.; Miller, R.

Surface tension experiments were performed using the drop profile analysis tensiometry method. The hexane was injected into the measuring cell at certain times before the formation of the solution drop. The influence of the capillary diameter and solution drop size on the measured apparent dynamic surface tension was studied. The amount of hexane transferred from the vapor phase to the drop was estimated. For large pure water drops, it was shown that the ageing of the drop in the hexane vapor during a long time resulted in the formation of a liquid hexane phase covering the drop, but the volume of this phase did not exceed 0.5 mm3. On the contrary, for surfactant solution drops the volume of the hexane phase covering the drop was essentially larger. Experiments with solution drops were performed to measure the surface tension within a wide range of surfactant concentration. It was found that the dependencies of dynamic surface tension on the C13DMPO and C14EO8 solutions concentration exhibit maxima at concentrations of about 1–2 μmol/L for C14EO8 and 2–5 μmol/L for C13DMPO at ageing times of 100 to 1000 s; these maxima were shown to exist also at equilibrium. This phenomenon is presumably ascribed to the competitive character of simultaneous adsorption of hexane and surfactant.

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Permalink: https://www.hzdr.de/publications/Publ-32205
Publ.-Id: 32205


Synergistic lanthanide extraction triggered by self-assembly of heterodinuclear Zn(II)/Ln(III) Schiff base/carboxylic acid complexes

Kelly, N.; Doert, T.; Hennersdorf, F.; Gloe, K.

The studies reported here focus on the extraction of La(III), Eu(III), and Yb(III) by chelating hexadentate 3-alkoxy-2-hydroxyphenyl substituted diimine ligands using the extraction system Ln(NO₃)₃–Zn(NO₃)₂–NaNO₃–buffer–H₂O/diimine-n-caprylic acid–CHCl₃. Significant synergistic enhancement has been observed for the Ln(III) extraction from nitrate media in the presence of Zn(II) and n-caprylic acid. These effects can be 15 interpreted by self-assembly of heterodinuclear Zn(II)/Ln(III) complexes with both deprotonated extractants in the organic phase taking into account solution and solid-state structural studies. The structures identified and the extraction behavior as well as the different factors influencing the process will be 20 discussed in detail. The goals of these experiments are to find preferred structure-extractability relationships for the synergistic systems investigated.

Keywords: Synergistic lanthanide extraction; Schiff base ligands; supramolecular chemistry; self-assembly of heterodinuclear Zn(II)/Ln(III) complexes; x-ray crystal structures

Permalink: https://www.hzdr.de/publications/Publ-32204
Publ.-Id: 32204


Rückgewinnung von Vanadium aus alkalischen Laugungslösungen unter der Synthese von Nanopartikeln

Kelly, N.; Sanchez Loredo, M. G.; Dupal, O.; Chekhonin, P.; Ebert, D.; Möckel, R.; O’Toole, N.; Reuter, M.

Europa ist auf den Import zahlreicher ökonomisch bedeutender Metalle angewiesen, wobei diese gleichzeitig in vielen sekundären Ressourcen gebunden sind, deren Potential nicht vollständig genutzt wird. Im Rahmen des CHROMIC-Projektes sollen kritische (Cr, Nb) und wertvolle (V, Mo) Metalle unter der Entwicklung innovativer Prozesse zurückgewonnen werden. Dabei erfolgt die gezielte Kombination einer verbesserten Vorbehandlung, einer selektiven alkalischen Laugung sowie einer hoch selektiven Metallrückgewinnung.
Im Zuge des hydrometallurgischen Verfahrens können verdünnte vanadiumhaltige Lösungen erhalten werden, welche für eine effektive Rückgewinnung des Zielmetalls weiter angereichert und aufgereinigt werden müssen. Der vorliegende Beitrag beinhaltet den Vergleich eines mehrstufigen Fällungs- und Solvent-extraktionsprozesses mit der direkten Fällung von Vanadaten aus den beladenen organischen Phasen. Letztere ermöglicht zugleich die Synthese von Nanopartikeln unterschiedlicher Metallvanadate. Der Einfluss der experimentellen Parameter (z. B. Art des Kations, Konzentration von Fällungs- und Extraktionsmitteln sowie des Zielmetalls) wird näher diskutiert, wobei die isolierten Produkte mittels XRD, XRF sowie REM-EDX strukturell charakterisiert werden.

  • Lecture (Conference)
    Jahrestreffen der ProcessNet-Fachgruppen Fluidverfahrenstechnik, Adsorption und Extraktion, 26.-28.02.2020, Berchtesgaden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-32203
Publ.-Id: 32203


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