Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

"Online First" included
Without submitted and only approved publications
Only approved publications

35043 Publications

Field-induced valence fluctuations in YbB12

Kurihara, R.; Miyake, A.; Tokunaga, M.; Ikeda, A.; Matsuda, Y. H.; Miyata, A.; Gorbunov, D.; Nomura, T.; Zherlitsyn, S.; Wosnitza, J.

We performed high-magnetic-field ultrasonic experiments on YbB12 up to 59 T to investigate the valence fluctuations in Yb ions. In zero field, the longitudinal elastic constant C11, the transverse elastic constants C44 and (C11 −C12)/2, and the bulk modulus CB show a hardening with a change of curvature at around 35 K indicating a small contribution of valence fluctuations to the elastic constants. When high magnetic fields are applied at low temperatures, CB exhibits a softening above a field-induced insulator-metal transition signaling field-induced valence fluctuations. Furthermore, at elevated temperatures, the field-induced softening of CB takes place at even lower fields and CB decreases continuously with field. Our analysis using the multipole susceptibility based on a two-band model reveals that the softening of CB originates from the enhancement of multipole-strain interaction in addition to the decrease of the insulator energy gap. This analysis indicates that field-induced valence fluctuations of Yb cause the instability of the bulk modulus CB.

Publ.-Id: 32373

SC-XRD data of U13 cluster

Fichter, S.; Radoske, T.; Ikeda-Ohno, A.

Collected frames of SC-XRD measurement of crystal consisting of U13 cluster. Refined cif file is also included.

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-03-04
    DOI: 10.14278/rodare.829


Publ.-Id: 32371

Experimental studies on bubble aspect ratio and corresponding correlations under bubble swarm condition

Liu, L.; Zhang, H.; Yan, H.; Ziegenhein, T.; Heßenkemper, H.; Zhou, P.; Lucas, D.

Zip-file that contains the raw images on a study on bubble aspect ratio under swarm condition. Further information can be found in the respective paper.

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-03-02
    DOI: 10.14278/rodare.827
    License: CC-BY-4.0


Publ.-Id: 32366

Data for: Bremsstrahlung emission and plasma characterization driven by moderately relativistic laser–plasma interactions

Singh, S.; Armstrong, C. D.; Kang, N.; Ren, L.; Liu, H.; Hua, N.; Rusby, D. R.; Klimo, O.; Versaci, R.; Zhang, Y.; Sun, M.; Zhu, B.; Lei, A.; Ouyang, X.; Lancia, L.; Laso Garcia, A.; Wagner, A.; Cowan, T. E.; Zhu, J.; Schlegel, T.; Weber, S.; McKenna, P.; Neely, D.; Tikhonchuk, V.; Kumar, D.

Relativistic electrons generated by the interaction of petawatt-class short laser pulses with solid targets can be used to generate bright x-rays via bremsstrahlung. The efficiency of laser energy transfer into these electrons depends on multiple parameters including the focused intensity and pre-plasma level. This paper reports experimental results from the interaction of a high intensity petawatt-class glass laser pulses with solid targets at a maximum intensity of 1019 W cm−2. In-situ measurements of specularly reflected light are used to provide an upper bound of laser absorption and to characterize focused laser intensity, the pre-plasma level and the generation mechanism of second harmonic light. The measured spectrum of electrons and bremsstrahlung radiation provide information about the efficiency of laser energy transfer.

Keywords: Plasma physics; Bremsstrahlung; Laser-plasma

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-06
    DOI: 10.14278/rodare.825
    License: CC-BY-4.0


Publ.-Id: 32365

HZDR Multiphase Case Collection for OpenFOAM

Hänsch, S.; Draw, M.; Evdokimov, I.; Khan, H.; Krull, B.; Lehnigk, R.; Liao, Y.; Lyu, H.; Meller, R.; Schlegel, F.; Tekavčič, M.
Other: Couteau, Arthur; Other: Upadhyay, Kartik; Other: Mohite, Onkar; Other: Kriebitzsch, Sebastian

HZDR Multiphase Case Collection for OpenFOAM contains simulation setups for the open-source CFD software OpenFOAM with the HZDR multiphase addon. The simlation setups are separated into polydisperse bubbly flows utilizing the HZDR Baseline model set according to Liao et al. (Chem Eng Sci, 2019, Vol. 202, 55-69) and setups for a hybrid modelling approach (disperse and resolved interfaces) according to Meller et al. (Int J Numer Meth Fluids. 2020, 1-26).

Cases using the HZDR Baseline model set







Cases utlizing the hybrid modelling approach


Keywords: Multiphase Flow; Numerical Simulations; OpenFOAM; CFD; Baseline model; Multi-field two-fluid model; Eulerian-Eulerian model; Free Surface

  • Software in the HZDR data repository RODARE
    Publication date: 2021-02-15
    DOI: 10.14278/rodare.811
    License: CC-BY-4.0


Publ.-Id: 32364

Control Over Self-Assembled Janus Clusters by the Strength of Magnetic Field in H₂O₂

Alsaadawi, Y.; Eichler-Volf, A.; Heigl, M.; Zahn, P.; Albrecht, M.; Erbe, A.

Microscope video of capped Janus particles propelled in Hydrogen peroxide under influence of varying magnetic fields. The caps compose of ferromagnetic (Co) and paramagnetic (Pd, H2O2 catalyst) elements carefully deposited onto one hemisphere of silica particles, which will later exhibit aligned magnetic moments upon saturation in 1 T magnetic field. The videos demonstrate different motion profiles depending on cluster shapes, with the later determined by cap-cap interaction of individual particles. 

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-03-01
    DOI: 10.14278/rodare.823


Publ.-Id: 32363


Fridman, Emil

ASTRID-DYN3D: XS generation and full core simulations

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-25
    DOI: 10.14278/rodare.821


Publ.-Id: 32353

Spatially resolved Eu(III) environments by chemical microscopy

Drobot, B.

Archiv of research data for the manuscript

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-24
    DOI: 10.14278/rodare.819


Publ.-Id: 32350

Microfocus X-ray Computed Tomography of a Plastic Toy ("HIPPO"): Projection Data

Boden, S.

Raw and preprocessed projection data from a microfocus X-ray CT of a plastic toy ("HIPPO"). To be used as demo dataset for the PARIS reconstruction framework.

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-23
    DOI: 10.14278/rodare.817


Publ.-Id: 32348

Cytoplasmic localization of prostate-specific membrane antigen inhibitors may confer advantages for targeted cancer therapies.

Matthias, J.; Engelhardt, J.; Schäfer, M.; Bauder-Wüst, U.; Meyer, P.; Haberkorn, U.; Eder, M.; Kopka, K.; Hell, S.; Eder, A.

Targeted imaging and therapy approaches based on novel prostate-specific membrane antigen (PSMA) inhibitors have fundamentally changed the treatment regimen of prostate cancer. However, the exact mechanism of PSMA inhibitor internalization has not yet been studied, and the inhibitors' subcellular fate remains elusive. Here we investigated the intracellular distribution of peptidomimetic PSMA inhibitors and of PSMA itself by stimulated emission depletion (STED) nanoscopy, applying a novel non-standard live cell staining protocol. Imaging analysis confirmed PSMA cluster formation at the cell surface of prostate cancer cells and clathrin-dependent endocytosis of PSMA inhibitors. Following the endosomal pathway, PSMA inhibitors accumulated in prostate cancer cells at clinically relevant time points. In contrast to PSMA itself, PSMA inhibitors were found to eventually distribute homogeneously in the cytoplasm, a molecular condition that promises benefits for treatment as cytoplasmic and in particular perinuclear enrichment of the radionuclide carriers may better facilitate the radiation-mediated damage of cancerous cells. This study is the first to reveal the subcellular fate of PSMA/PSMA inhibitor complexes at the nanoscale and aims to inspire the development of new approaches in the field of prostate cancer research, diagnostics, and therapeutics.

Keywords: Prostate Cancer; Prostate-Specific Membrane Antigen; Dual-Labeled PSMA Inhibitors; Stimulated Emission Depletion Nanoscopy; Theranostics

Publ.-Id: 32347

Controlled Generation of Luminescent Centres in Hexagonal Boron Nitride by Irradiation Engineering

Fischer, M.; Caridad, J. M.; Sajid, A.; Ghaderzadeh, S.; Ghorbani Asl, M.; Gammelgaard, L.; Bøggild, P.; Thygesen, K. S.; Krasheninnikov, A.; Xiao, S.; Wubs, M.; Stenger, N.

Luminescent centres in the two-dimensional material hexagonal boron nitride have the potential to enable quantum applications at room temperature. In order to be utilized for applications it is crucial to generate these centres in a controlled manner and to identify their microscopic nature. Here we present a novel method inspired by irradiation engineering with oxygen atoms. We explore systematically the influence of the kinetic energy and the irradiation fluence on the generation of luminescent centres. We find modifications of their density for both parameters while a five-fold enhancement is observed with increasing fluence. Molecular dynamics simulations clarify the generation mechanism of these centres and their microscopic nature. We infer that V_N C_B and V_B are the most likely centres formed. Ab initio calculations of their optical properties show excellent agreement with our experiments. Our methodology generates quantum emitters in a controlled manner and provides new insights into their microscopic nature.

Keywords: two-dimensional materials; hexagonal boron nitride; defect engineering; ion irradiation; luminescent centre; quantum emitter

Publ.-Id: 32345

Fractional Quantum Conductance Plateaus in Mosaic-Like Conductors and Their Similarities to the Fractional Quantum Hall Effect

Kisslinger, F.; Rienmüller, D.; Ott, C.; Kampert, W. A. G.; Weber, H. K.

A simple route to generate magnetotransport data is reported that results in fractional quantum Hall plateaus in the conductance without invoking strongly correlated physics. Ingredients to the generating model are conducting tiles with integer quantum Hall effect and metallic linkers, further irchhoff rules. When connecting few identical tiles in a mosaic, fractional steps occur in the conductance values. Richer spectra representing several fractions occur when the tiles are parametrically varied. Parts of the simulation data are supported with purposefully designed graphene mosaics in high magnetic fields. The findings emphasize that the occurrence of fractional conductance values, in particular in two-terminal measurements, does not necessarily indicate interaction-driven physics. The importance of an independent determination of charge densities is underscored and similarities with and differences to the fractional quantum Hall effect are critically discussed.

Publ.-Id: 32344

Magnetic anisotropy and spin dynamics in the kagome magnet Fe4Si2Sn7O16: NMR and magnetic susceptibility study on oriented powder

Dengre, S.; Sarkar, R.; Opherden, L.; Herrmannsdörfer, T.; Allison, M.; Söhnel, T.; Ling, C. D.; Gardner, J. S.; Klauss, H.-H.

Fe4Si2Sn7O16 hosts an undistorted kagome lattice of Fe2+ (3d6, S = 2) ions. We present results of bulk magnetization and Sn nuclear magnetic resonance (NMR) measurements on an oriented Fe4Si2Sn7O16 powder sample oriented in geometries parallel (II) and perpendicular (⊥) to the external applied magnetic field used for orienting the powder (Bori). The bulk susceptibility χ shows a broad peak at TN ∼ 3 K associated with antiferromagnetic ordering. NMR spectra indicate the presence of planar anisotropy in the kagome planes. From an analysis of the static NMR shift (K) and dynamic spin-lattice relaxation rate (1/T1) we conclude the presence of dominant magnetic fluctuations in the kagome planes. For the II orientation, K scales linearly with the bulk susceptibility for temperatures down to ∼4 K, while in the ⊥ orientation K starts to deviate strongly below T ∼ 30 K. We associate this deviation with the onset of spin-tilting towards the kagome planes. These correlations are also reflected in the 1/T1 data for the II orientation, which starts to decrease below T ∼ 30 K. In this correlated regime, TN < T < ∼30 K, we discuss the formation of positive chiral spin correlations in the kagome planes.

Publ.-Id: 32343

Magnetic and structural dimer networks in layered K2Ni(MoO4)2

Murugan, G. S.; Ramesh Babu, K.; Sankar, R.; Chen, W. T.; Panneer Muthuselvam, I.; Chattopadhyay, S.; Choi, K.-Y.

The magnetic and thermodynamic properties of layered single-crystal K2Ni(MoO4)2 having both structural and magnetic dimers have been investigated. The crystal structure of K2Ni(MoO4)2 is composed of edge-sharing NiO6-octahedral pairs bridged by the MoO4 2− polyatomic ion groups in a plane, and the K+ ions sit in the van der Waals gap between the layers. The temperature dependence of magnetic susceptibility shows a spin-singlet ground state with an activation gap of Δ/kB ≈ 38 K. A high-field magnetization study at T = 1.5 K exhibits a half-magnetization plateau at μ0H ∼ 25 T, corresponding to a level crossing of the singlet ground state with the lowest triplet state. Further, we have performed density functional theory calculations to determine magnetic exchange interactions. The nearest-neighbor coupling constant J1 ∼ 10 K between the Ni spins turns out to be an order of magnitude larger than all interdimer couplings. Our experimental and theoretical results suggest that K2Ni(MoO4)2 constitutes a nearly isolated two-dimensional S = 1 dimer model.

Publ.-Id: 32341

Experimental evidence for Zeeman spin–orbit coupling in layered antiferromagnetic conductors

Ramazashvili, R.; Grigoriev, P. D.; Helm, T.; Kollmannsberger, F.; Kunz, M.; Biberacher, W.; Kampert, W. A. G.; Fujiwara, H.; Erb, A.; Wosnitza, J.; Gross, R.; Kartsovnik, M. V.

Most of solid-state spin physics arising from spin–orbit coupling, from fundamental phenomena to industrial applications, relies on symmetry-protected degeneracies. So does the Zeeman spin–orbit coupling, expected to manifest itself in a wide range of antiferromagnetic conductors. Yet, experimental proof of this phenomenon has been lacking. Here we demonstrate that the Néel state of the layered organic superconductor κ-(BETS)2FeBr4 shows no spin modulation of the Shubnikov–de Haas oscillations, contrary to its paramagnetic state. This is unambiguous evidence for the spin degeneracy of Landau levels, a direct manifestation of the Zeeman spin–orbit coupling. Likewise, we show that spin modulation is absent in electron-doped Nd1.85Ce0.15CuO4, which evidences the presence of Néel order in this cuprate superconductor even at optimal doping. Obtained on two very different materials, our results demonstrate the generic character of the Zeeman spin–orbit coupling.

Publ.-Id: 32340

CTF and FLOCAL Thermal Hydraulics Validations and Verifications within a Multiscale and Multiphysics Software Development

Davies, S.; Rohde, U.; Litskevich, D.; Merk, B.; Bryce, P.; Levers, A.; Detkina, A.; Atkinson, S.; Ravindra, V.

Simulation codes allow to reduce the high conservativism in nuclear reactor design improving the reliability and sustainability associated to nuclear power. Full core coupled reactor physics at the rod level are not provided by most simulation codes. This has led in the UK to the development of a multiscale and multiphysics software development focused on LWRS. In terms of the thermal hydraulics, simulation codes suitable for this multiscale and multiphysics software development include the subchannel code CTF and the thermal hydraulics module FLOCAL of the nodal code DYN3D. In this journal article, CTF and FLOCAL thermal hydraulics validations and verifications within the multiscale and multiphysics software development have been performed to evaluate the accuracy and methodology available to obtain thermal hydraulics at the rod level in both simulation codes. These validations and verifications have proved that CTF is a highly accurate sub-channel code for thermal hydraulics. Also, these verifications have proved that CTF provides a wide range of crossflow and turbulent mixing methods while FLOCAL provides in general the simplified no crossflow method as the rest of the methods were only tested during its implementation into DYN3D.

Keywords: Nuclear Reactor; Thermal Hydraulics; Simulation; Subchannel Code; CTF; FLOCAL; PSBT

Publ.-Id: 32337

Effect of deposition current density on the Co–Ni/SiO2 alloy composite coatings Using Scanning Jet Electrodeposition

Jiang, Wei; Qiu, M.; Shen, L.; Lou, G.; Yang, X.; Eckert, K.; Tian, Z.

Co–Ni/SiO2 alloy composite coatings were electrodeposited on copper substrate by scanning jet electrodeposition at various current densities to study its effect on the deposite morphologies, texture orientation, microhardness, adhesion force, wear resistance and corrosion resistance of Co–Ni/SiO2 alloy composite coatings. The structure and performance of the material were characterized using scanning electron microscope, XRD diffractometer, nanoindentation, scratch tester, friction and wear tester and electrochemical methods. The morphologies of the Co–Ni/SiO2 alloy composite coatings changed from sparse and slender structures to dense starfish structures with an increase in current density. A part of Co precipitated in the form of a face-centered cubic structure and formed a solid solution with Ni, while another part of Co precipitated in the structure of the composite coating in the form of a hexagonal close-packed structure. The Co–Ni/SiO2 alloy composite coating exhibited excellent adhesion force, wear resistance and corrosion resistance when the deposition current density was 130 A/dm2. Once the current density was exceeded, some microcracks appeared on the surface of the composite coating, after which the adhesion force and corrosion resistance decreased. The present study suggests that current density at 130 A/dm2 is more suitable than low current density for jet electrodeposition to prepare high-density and high-quality composite coating.

Keywords: Co–Ni/SiO2; Scanning jet electrodeposition; Deposition current density


  • Secondary publication expected from 11.02.2022

Publ.-Id: 32336

Defective Nanographenes Containing Seven-Five-Seven (7–5–7)-Membered Rings

Fei, Y.; Fu, Y.; Bai, X.; Du, L.; Li, Z.; Komber, H.; Low, K.-H.; Zhou, S.; Lee Phillips, D.; Feng, X.; Liu, J.

Defects have been observed in graphene and are expected to playa key role in its optical, electronic, and magnetic properties. However, becausemost of the studies focused on the structural characterization, the implications oftopological defects on the physicochemical properties of graphene remain poorlyunderstood. Here, we demonstrate a bottom-up synthesis of three novelnanographenes (1−3) with well-defined defects in which seven-five-seven (7−5−7)-membered rings were introduced to their sp2carbon frameworks. From theX-ray crystallographic analysis, compound1adopts a nearly planar structure.Compound2, with an additionalfive-membered ring compared to1, possesses aslightly saddle-shaped geometry. Compound3, which can be regarded as the“head-to-head”fusion of1with two bonds, features two saddles connectedtogether. The resultant defective nanographenes1−3were well-investigated byUV−vis absorption, cyclic voltammetry, and time-resolved absorption spectra and further corroborated by density functional theory(DFT) calculations. Detailed experimental and theoretical investigations elucidate that these three nanographenes1−3exhibit ananti-aromatic character in their ground states and display a high stability under ambient conditions, which contrast with the reportedunstable biradicaloid nanographenes that contain heptagons. Our work reported herein offers insights into the understanding ofstructure-related properties and enables the control of the electronic structures of expanded nanographenes with atomically precise defects.


  • Secondary publication expected from 27.01.2022

Publ.-Id: 32328

Effect of PAA-induced surface etching on the adhesion properties of ZnO nanostructured films

Meinderink, D.; Kielar, C.; Sobol, O.; Ruhm, L.; Rieker, F.; Nolkemper, K.; Orive, A. G.; Ozcan, O.; Grundmeier, G.

Zinc oxide - polymer interfaces are known to exhibit interesting properties regarding molecular adhesion. This work is aimed at the investigation of the effect of the morphology and surface chemistry on the macroscopic adhesion of a model epoxy-based adhesive to nanorod (ZnO NR) and nanocrystalline (ZnO NC) ZnO-modified surfaces. Both ZnO films have been prepared using hydrothermal synthesis on hot-dip galvanized steel (HDG) surfaces by varying the precursor chemistry in order to control the film morphology. Poly (acrylic acid) (PAA) was used to improve the interfacial adhesion by modifying the morphology and surface chemistry of ZnO nanostructured films. The strong interaction of PAA from a dilute and neutral aqueous solution with the ZnO nanocrystallites was shown to significantly improve the interfacial adhesion by means of a nanoetching process. It was shown that the wet peel-forces correlate well with the considered morphology and surface chemistry.

Keywords: ZnO nanorods; Nanocrystalline ZnO films; Adhesion by mechanical interlocking; Poly(acrylic acid); Morphology control; Interfacial stability

Publ.-Id: 32327

Comprehensive Bonding Analysis of Tetravalent f-Element Complexes of the Type [M(salen)2]

Kloditz, R.; Radoske, T.; Schmidt, M.; Heine, T.; Stumpf, T.; Patzschke, M.

Zip-File with the xyz-files of the optimized structures of the studied complexes. Further information can be found in the respective paper and supplementary information.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-18
    DOI: 10.14278/rodare.815
    License: CC-BY-4.0


Publ.-Id: 32325

Comprehensive Bonding Analysis of Tetravalent f-Element Complexes of the Type [M(salen)₂]

Kloditz, R.; Radoske, T.; Schmidt, M.; Heine, T.; Stumpf, T.; Patzschke, M.

Key questions for the study of chemical bonding in actinide compounds are the degree of covalency that can be realized in the bonds to different donor atoms and the relative participation of 5f and 6d orbitals. A manifold of theoretical approaches is available to address these questions, but hitherto no comprehensive assessments are available. Here, we present an in-depth analysis of the metal–ligand bond in a series of actinide metal–organic compounds of the [M(salen)₂] type (M = Ce, Th, Pa, U, Np, Pu) with the Schiff base N,N′-bis(salicylidene)ethylenediamine (salen). All compounds except the Pa complex (only included in the calculations) have been synthesized and characterized experimentally. The experimental data are then used as a basis to quantify the covalency of bonds to both N- and O-donor atoms using simple electron-density differences and the quantum theory of atoms in molecules (QTAIM) with interacting quantum atoms. In addition, the orbital origin of any covalent contributions was studied via natural population analysis (NPA). The results clearly show that the bond to the hard, charged O-donor atoms of salen is consistently not only stronger but also more covalent than bonds to the softer N-donor atoms. On the other hand, in a comparison of the metals, Th shows the most ionic bond character even compared to its 4f analogue Ce. A maximum of the covalency is found for Pa or Np by their absolute and relative covalent bond energies, respectively. This trend also correlates with a significant f- and d-orbital occupation for Pa and Np. These results underline that only a comprehensive computational approach is capable of fully characterizing the covalency in actinide complexes.

Keywords: Actinides; Covalency; QTAIM; Coordination Chemistry; Metal-organic Chemistry; DFT; Electron Density

Related publications

Publ.-Id: 32324

Multilayer interfacial wave dynamics in upright circular cylinders with application to liquid metal batteries

Horstmann, G. M.

Liquid metal batteries (LMBs) are discussed today as an economic grid-scale energy storage, as required for the deployment of fluctuating renewable energies. These batteries consist of three stably stratified liquid layers: two liquid metal electrodes are separated by a thin molten salt electrolyte, this way forming an electrochemical concentration cell. Their completely liquid interior, which is on the one hand very beneficial for the energy efficiency, also poses some major challenges on the other hand. Strong cell currents in combination with electromagnetic fields make liquid metal batteries highly susceptible to various kinds of magnetohydrodynamic instabilities. In particular, the so-called metal pad roll instability (MPRI), which can drive uncontrollable wave motions in both interfaces, was identified as a key limiting factor for the batteries' operational safety.
In this seminar talk, I will present the key results of my PhD thesis, where I was concerned with multilayer interfacial wave dynamics in cylindrical LMB models. In the fist part, I will show the results of a potential flow theory describing gravity–capillary waves in three-layer stratifications. The theory is used to classify different wave coupling states, which comprise different manifestations of the MPRI. Accompanying numerical simulations substantiate that coupling effects will be present in most future LMBs. In the second part, a multilayer sloshing experiment will be introduced, which allows to mechanically excite the same interfacial wave motions as induced by the MPRI. Different sets of experiments emphasize the crucial role of the contact line as well as of viscous damping, both having a strong impact on instability onsets of cylindrical LMBs. In the final part, I will present a new hybrid interfacial sloshing model, which accounts for viscous damping and can explain the experimentally observed resonance dynamics. As a further unexpected result, the sloshing theory predicts the formation of novel spiral wave patterns under the effect of strong damping in higher wave modes.

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    Online seminars of the Morelia Unit of the Materials Research Institute at the National University of Mexico, 12.02.2021, Mexico City, Mexico

Publ.-Id: 32322

Photons or protons for reirradiation in (non-)small cell lung cancer: Results of the multicentric ROCOCO in silico study

Troost, E. G. C.; Wink, K. C. J.; Roelofs, E.; Simone Ii, C. B.; Makocki, S.; Löck, S.; van Kollenburg, P.; Dechambre, D.; Minken, A. W. H.; van der Stoep, J.; Avery, S.; Jansen, N.; Solberg, T.; Bussink, J.; de Ruysscher, D.

Objective: Locally recurrent disease is of increasing concern in (non-) small cell lung cancer [(N)SCLC] patients. Local reirradiation with photons or particles may be of benefit to these patients. In this multicentre in silico trial performed within the Radiation Oncology Collaborative Comparison (ROCOCO) consortium, the doses to the target volumes and organs at risk (OARs) were compared when using several photon and proton techniques in patients with recurrent localised lung cancer scheduled to undergo reirradiation. Methods: 24 consecutive patients with a second primary (N)SCLC or recurrent disease after curative-intent, standard fractionated radio(chemo)therapy were included in this study. The target volumes and OARs were centrally contoured and distributed to the participating ROCOCO sites. Remaining doses to the OARs were calculated on an individual patient’s basis. Treatment planning was performed by the participating site using the clinical treatment planning system and associated beam characteristics. Results: Treatment plans for all modalities (five photon and two proton plans per patient) were available for 22 patients (N = 154 plans). 3D-conformal photon therapy and double-scattered proton therapy delivered significantly lower doses to the target volumes. The highly conformal techniques, i.e., intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), CyberKnife, TomoTherapy and intensity-modulated proton therapy (IMPT), reached the highest doses in the target volumes. Of these, IMPT was able to statistically significantly decrease the radiation doses to the OARs. Conclusion: Highly conformal photon and proton beam techniques enable high-dose reirradiation of the target volume. They, however, significantly differ in the dose deposited in the OARs. The therapeutic options, i.e., reirradiation or systemic therapy, need to be carefully weighed and discussed with the patients. Advances in knowledge: Highly conformal photon and proton beam techniques enable high-dose reirradiation of the target volume. In light of the abilities of the various highly conformal techniques to spare specific OARs, the therapeutic options need to be carefully weighed and patients included in the decision-making process.

Publ.-Id: 32317

Specific requirements for translation of biological research into clinical radiation oncology

Krause, M.; Alsner, J.; Linge, A.; Bütof, R.; Löck, S.; Bristow, R.

Radiotherapy has been optimized over the last decades not only through technological advances, but also through the translation of biological knowledge into clinical treatment schedules. Optimization of fractionation schedules and/or the introduction of simultaneous combined systemic treatment have significantly improved tumour cure rates in several cancer types.
With modern techniques, we are currently able to measure factors of radiation resistance or radiation sensitivity in patient tumours; the definition of new biomarkers is expected to further enable personalized treatments. In this Review article, we overview important translation paths and summarize the quality requirements for preclinical and translational studies that will help to avoid bias in trial results.

Keywords: biomarkers; clinical trials; personalized treatment; quality; radiotherapy; translational research

Publ.-Id: 32316

X-ray Spectroscopic Studies of a Solid-Density Germanium Plasma Created by a Free Electron Laser

Perez-Callejo, G.; Vinko, S. M.; Ren, S.; Royle, R.; Humphries, O. S.; Preston, T. R.; Hammel, B. A.; Chung, H.-K.; Burian, T.; Vozda, V.; Lin, M.-F.; Brandt Van Driel, T.; Wark, J. S.

The generation of solid-density plasmas in a controlled manner using an X-ray free electron laser (XFEL) has opened up the possibility of diagnosing the atomic properties of hot, strongly coupled systems in novel ways. Previous work has concentrated on K-shell emission spectroscopy of low Z (<= 14) elements. Here, we extend these studies to the mid-Z(=32) element Germanium, where the XFEL creates copious L-shell holes, and the plasma conditions are interrogated by recording of the associated L-shell X-ray emission spectra. Given the desirability of generating as uniform a plasma as possible, we present here a study of the effects of the FEL photon energy on the temperatures and electron densities created, and their uniformity in the FEL beam propagation direction. We show that good uniformity can be achieved by tuning the photon energy of the XFEL such that it does not overlap significantly with L-shell to M-shell bound-bound transitions, and lies below the L-edges of the ions formed during the heating process. Reasonable agreement between experiment and simulations is found for the emitted X-ray spectra, demonstrating that for these higher Z elements, the selection of appropriate XFEL parameters is important for achieving uniformity in the plasma conditions.

Keywords: High energy density; Plasma opacity; XFEL; spectroscopy

Publ.-Id: 32312

Mineral Dissolution Rates: Importance of Surface Reactivity

Schabernack, J.; Fischer, C.

Mineral dissolution plays a key role in many environmental and technical fields, e.g., weathering, building materials, as well as host rock characterization for potential nuclear waste repositories. The rate of mineral dissolution in water is controlled by two parameters: (1) transport of dissolved species over and from the interface determined by advective fluid flow and diffusion (transport control) and (2) crystal surface reactivity (surface reactivity control). Current reactive transport models (RTM) simulating species transport commonly calculate mineral dissolution by using rate laws [1]. These rate laws solely depend on species concentration in the fluid and therefore do not include intrinsic variability of surface reactivity. Experimental studies under surface-controlled conditions have shown a heterogeneous distribution of reaction rates [2]. This rate heterogeneity is caused by nanotopographical structures on the crystal surface, such as steps and etch pits that are generated at lattice defects. At these structures, the high density of reactive kink sites is leading to a local increase in dissolution rates.
In this study, we test whether experimentally observed rate heterogeneities can be reproduced by using current RTMs. We apply a standard RTM approach combined with the measured surface topography of a calcite single crystal [2]. Calcite is one of the larger mineral components in the sandy facies of the Opalinus clay formation, that is under consideration for nuclear waste storage. The calculated surface dissolution rate maps are compared to experimentally derived rate maps. The results show that the measured rate heterogeneities cannot be reproduced with the existing RTM approach. To improve the predictive capabilities of RTMs, the surface reactivity that is intrinsic to the mineral needs to be implemented into rate calculations. Investigating calcite surface reactivity in the context of dissolution can also yield information about other kinetic surface processes such as the adsorption of radionuclides. We discuss parameterization of surface reactivity via proxy parameters, such as surface roughness or surface slope. The implementation of these proxy parameters will allow for a more precise prediction of host rock-fluid interaction over large time scales in RTMs, relevant for safety assessment.
[1] P. Agrawal, A. Raoof, O. Iliev and M. Wolthers, Evolution of pore-shape and its impact on pore conductivity during CO2 injection in calcite: Single pore simulations and microfluidic experiments, Advances in Water Resources, 136, 103480 (2020).
[2] I. Bibi, R.S. Arvidson, C. Fischer and A. Luttge: Temporal Evolution of Calcite Surface Dissolution Kinetics, Minerals, 8, 256 (2018).

Keywords: Reactive Transport Model; Mineral Dissolution; Crystal Surface Reactivity

  • Poster (Online presentation)
    2. Tage der Standortauswahl, 11.-12.02.2021, Freiberg, Germany

Publ.-Id: 32309

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

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

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.

Related publications

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.


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.

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

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

Publ.-Id: 32299

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)

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.

Publ.-Id: 32295

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.

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.

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.

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.


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.


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.

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

Publ.-Id: 32289

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.

Publ.-Id: 32286

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

Publ.-Id: 32282

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.

Publ.-Id: 32279

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 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

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

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-08
    DOI: 10.14278/rodare.799


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

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-09
    DOI: 10.14278/rodare.806
    License: CC-BY-4.0


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.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-08
    DOI: 10.14278/rodare.804


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. 

Related publications

  • Software in the HZDR data repository RODARE
    Publication date: 2021-02-08
    DOI: 10.14278/rodare.802


Publ.-Id: 32273

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

Publ.-Id: 32271

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.

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

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

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


Publ.-Id: 32264

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.


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.


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.


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.


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.


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.

Publ.-Id: 32255

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

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-28
    DOI: 10.14278/rodare.769


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

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

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.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-28
    DOI: 10.14278/rodare.771
    License: CC-BY-4.0


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

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

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-29
    DOI: 10.14278/rodare.785


Publ.-Id: 32249

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

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

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.

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

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

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

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

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.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-31
    DOI: 10.14278/rodare.792
    License: CC-BY-4.0


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
[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

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

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

  • Lecture (Conference) (Online presentation)

Publ.-Id: 32231

Helium Ion Microscope based nanofabrication

Hlawacek, G.

Helium Ion Microscope based nanofabrication

Keywords: HIM; nanofabrication; GFIS

  • Lecture (others) (Online presentation)
    Nanofabrication webinar series @ Master on Advanced Nanoscience and Nanotechnology, 23.04.2020, Barcelona, Spain

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


Publ.-Id: 32229

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

Publ.-Id: 32226

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

Publ.-Id: 32224

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.

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

Publ.-Id: 32220

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

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

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

Publ.-Id: 32215

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


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.

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

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-29
    DOI: 10.14278/rodare.783
    License: CC-BY-4.0


Publ.-Id: 32210

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

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

Publ.-Id: 32207

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.

Related publications


Publ.-Id: 32205

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

Publ.-Id: 32203

Interfacial Properties of Tridecyl Dimethyl Phosphine Oxide Adsorbed at the Surface of a Solution Drop in Hexane Saturated Air

B. Fainerman, V.; V. Aksenenko, E.; V. Makievski, A.; Liggieri, L.; Mucic, N.; Javadi, A.; I. Kovalchuk, V.; Miller, R.

The surface tension of C13DMPO aqueous solution drops in hexane vapor is studied using the drop profile method. The hexane was injected into the measuring cell at three different conditions: before the formation of the solution drop, at a certain moment during the adsorption process, and after reaching the equilibrium of surfactant adsorption. The surface tension values for all experiments at the same concentration and different injection situations ultimately coincide with each other after attaining the final equilibration stage. The equilibrium surface tension isotherms of C13DMPO solutions, and the adsorption of both components—surfactant and hexane—were calculated. It was shown that the presence of surfactant leads to an increased hexane adsorption.

Keywords: drop profile analysis tensiometry; surfactant adsorption; solution–alkane vapor interface; dynamic surface tension; thermodynamic model; non-ionic surfactant

Related publications

Publ.-Id: 32202

Salt Effects on Formation and Stability of Colloidal Gas Aphrons Produced by Anionic and Zwitterionic Surfactants in Xanthan Gum Solution

Keshavarzi, B.; Mahmoudvand, M.; Javadi, A.; Bahramian, A.; Miller, R.; Eckert, K.

 This work is devoted to the influence of NaCl salt concentration on the formation and stability of colloidal gas aphrons (CGA) produced by the anionic surfactant sodium dodecyl sulfate (SDS) and zwitterionic surfactant coco amido propyl betaine (CAPB) in the presence of xanthan gum (XG) as a stabilizer. Dynamic surface tension measurements as well as volume and half-life time of the produced foams are considered for stability analysis. A sharp decrease of the half-life time and volume of the CGAs at NaCl concentrations larger than 20,000 ppm was observed, which was attributed to the precipitation of SDS in the solution. The mentioned SDS precipitation altered the dynamic surface tension behavior, dilational surface elasticity, and turbidity of the solution. The main reason for the precipitation of SDS is the increased Krafft point caused by the addition of salt. However, for the zwitterionic surfactant CAPB, the effects of added NaCl on the interfacial properties required for CGAs production was negligible due to the simultaneous effects on the cationic and anionic head groups in the CAPB leading to negligible changes in the net repulsion forces. Yet, an overall reduction in the half-life time of CGAs with increasing salt concentration, even when we have no precipitation, was observed for both surfactants, which could be explained by the reduction in the ability of XG to increase the viscosity with increasing salt concentration.

Keywords: Colloidal gas aphrons; foam formation and stability; drilling fluid; dynamic surface tension; interfacial rheology; cocoamidopropyl betaine; sodium dodecyl sulfate; NaCl

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-02-11
    DOI: 10.14278/rodare.808
    License: CC-BY-4.0


Publ.-Id: 32201

Salt Effects on Formation and Stability of Colloidal Gas Aphrons Produced by Anionic and Zwitterionic Surfactants in Xanthan Gum Solution

Keshavarzi, B.; Mahmoudvand, M.; Javadi, A.; Bahramian, A.; Miller, R.; Eckert, K.

This work is devoted to the influence of NaCl salt concentration on the formation and stability of colloidal gas aphrons (CGA) produced by the anionic surfactant sodium dodecyl sulfate (SDS) and zwitterionic surfactant coco amido propyl betaine (CAPB) in the presence of xanthan gum (XG) as a stabilizer. Dynamic surface tension measurements as well as volume and half-life time of the produced foams are considered for stability analysis. A sharp decrease of the half-life time and volume of the CGAs at NaCl concentrations larger than 20,000 ppm was observed, which was attributed to the precipitation of SDS in the solution. The mentioned SDS precipitation altered the dynamic surface tension behavior, dilational surface elasticity, and turbidity of the solution. The main reason for the precipitation of SDS is the increased Krafft point caused by the addition of salt. However, for the zwitterionic surfactant CAPB, the effects of added NaCl on the interfacial properties required for CGAs production was negligible due to the simultaneous effects on the cationic and anionic head groups in the CAPB leading to negligible changes in the net repulsion forces. Yet, an overall reduction in the half-life time of CGAs with increasing salt concentration, even when we have no precipitation, was observed for both surfactants, which could be explained by the reduction in the ability of XG to increase the viscosity with increasing salt concentration.

Keywords: Colloidal gas aphrons; foam formation and stability; drilling fluid; dynamic surface tension; interfacial rheology; cocoamidopropyl betaine; sodium dodecyl sulfate; NaCl

Related publications


Publ.-Id: 32199

Hydrodynamic data of an operational single-pass cross-flow sieve tray

Vishwakarma, V.
Researcher: Schleicher, Eckhard; ContactPerson: Schubert, Markus; Supervisor: Hampel, Uwe

The hydrodynamic data of a single-pass cross-flow sieve tray equipped in an air/water column mockup (0.8 m dia.) are provided here. The uploaded data were obtained after processing the two-phase dispersion data acquired by a novel multi-probe flow profiler. Effective froth height distribution, 3D liquid holdup distribution, and tracer-based data (i.e., appearance time distribution (ATD) parameters and liquid velocity map) are provided for the studied loadings.    

Keywords: column tray; two-phase cross-flow; hydrodynamics; effective froth height; 3D liquid holdup; tracer-based data

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-28
    DOI: 10.14278/rodare.775


Publ.-Id: 32198

HZDR Multiphase Addon for OpenFOAM

Schlegel, F.; Draw, M.; Evdokimov, I.; Hänsch, S.; Khan, H.; Lehnigk, R.; Meller, R.; Petelin, G.; Tekavčič, M.
Other: Couteau, Arthur; Other: Colombo, Marco; Other: Kriebitzsch, Sebastian; Other: Parekh, Jigar

The HZDR multiphase addon contains additional code for the open-source CFD software OpenFOAM, released by The OpenFOAM Foundation. The developments are dedicated to the numerical simulation of multiphase flows, in particular to the multi-field two-fluid model (Euler-Euler method). Within the OpenFOAM library the multiphaseEulerFoam framework is used for this type of simulation. The addon contains a modified multiphaseEulerFoam named HZDRmultiphaseEulerFoam with the full support of the HZDR baseline model set for polydisperse bubbly flows according to Liao et al. (Chem Eng Sci, 2019, Vol. 202, 55-69). In addition a solver dedicated to a hybrid modelling approach (dispersed and resolved interfaces, Meller et al., Int J Numer Meth Fluids. 2020, 1-26) named cipsaMultiphaseEulerFoam is provided with the addon. This solver has an interface to the multiphaseEulerFoam framework and utilizes all available interfacial models of it.

General enhancements



  • morphology adaptive modeling framework for modelling of dispersed and resolved interfaces based on Eulerian multi-field two-fluid model
  • compact interpolation method according to Cubero et al. (Comput Chem Eng, 2014, Vol. 62, 96-107), including virtual mass
  • numerical drag according to Strubelj and Tiselj (Int J Numer Methods Eng, 2011, Vol. 85, 575-590) to describe resolved interfaces in a volume-of-fluid like manner
  • n-phase partial elimination algorithm for momentum equations to resolve strong phase coupling
  • free surface turbulence damping for k-ω SST (symmetric and asymmetric damping, Frederix et al., Nucl Eng Des, 2018, Vol. 333, 122-130)
  • selected tutorial cases:
    • a two-dimensional gas bubble, rising in a liquid, which is laden with micro gas bubbles, and
    • a two-dimensional stagnant stratification of water and oil, sharing a large-scale interface
    • a two-dimensional stratified flow based on the experiment of Fabre et al. (Multiphase Sci Technol, 1987, Vol. 3, 285–301)

Keywords: Multiphase Flow; Numerical Simulations; OpenFOAM; C++; CFD; Finite volume method; Baseline model; Multi-field two-fluid model; Eulerian-Eulerian model; Momentum interpolation; Partial elimination algorithm; Free Surface

  • Software in the HZDR data repository RODARE
    Publication date: 2021-01-26
    DOI: 10.14278/rodare.767
    License: GPL-3.0-only


Publ.-Id: 32194

Dynamics of Competitive Adsorption of Lipase and Ionic Surfactants at the Water–Air Interface

Javadi, A.; Dowlati, S.; Miller, R.; Schneck, E.; Eckert, K.; Kraume, M.

Lipase is one of the most important enzymes playing a key role in many biological and chemical processes, in particular for fat hydrolysis in living systems and technological applications such as food production, medicine, and biodiesel production. As lipase is soluble in water, the major hydrolysis process occurs at the water–oil interface, where lipase can get in contact with the oil. To provide optimum conditions, the emulsification of the oil is essential to provide a large interfacial area which is generally done by adding surfactants. However, the presence of surfactants can influence the lipase activity and also cause competitive adsorption, resulting in a removal of lipase from the interface or its conformational changes in the solution bulk. Here we have studied the dynamics of competitive adsorption and interfacial elasticity of mixed solutions containing lipase and the anionic surfactant sodium dodecyl sulfate (SDS) or the cationic surfactant cetyltrimethylammonium bromide (CTAB), respectively, at the water–air interface. The experiments were performed with a special coaxial double capillary setup for drop bulk–interface exchange developed for the drop profile analysis tensiometer PAT with two protocols: sequential and simultaneous adsorption of single components and mixed systems. The results in terms of dynamic surface tension and dilational viscoelasticity illustrate fast and complete desorption of a preadsorbed CTAB and SDS layers via subphase exchange with a buffer solution. In contrast, the preadsorbed lipase layer cannot be removed either by SDS or CTAB from the interface during drop bulk exchange with a buffer solution due to the unfolding process and conformation evolution of the protein molecules at the interface. In the opposite case, lipase can remove preadsorbed SDS and CTAB. The dynamic surface tension and viscoelasticity data measured before and after subphase exchange show joint adsorption of lipase and CTAB in the form of complexes, while SDS is adsorbed in competition with lipase. The results are in good correlation with the determined surface charges of the lipase gained by computational simulations which show a dominant negatively charged surface for lipase that can interact with the cationic CTAB while partial positively charged regions are observed for the interaction with the anionic SDS.

Related publications


Publ.-Id: 32189

Utilizing tailings material as strategic minerals and construction material

Dirlich, S.

The Polish-German joint project NOMECOR funded by the STAIR-II-program (BMBF, NCBR) investigated in the utilization of tailings material from a Polish flotation pond. The novel approach was to combine the valorization of strategic minerals with the utilization of the mineral compartments as construction material.
Conventional ammoniacal leaching combined with further processing steps has proven to be successful, while bioleaching was not really possible with the given composition of the material. In addition, the processing of the tailings material to be used as input material in cement production was also technically feasible.
The accompanying assessment of the innovative technologies in technological, environmental and economic respect, however, brought the conclusion that in particular the economic feasibility is not given with the proposed processing steps competing with very low deposition costs. At that stage the implementation concept was reconsidered to be more simplified using part of the tailings material directly after fractioning as construction material for building the dam, which was both technical and econmical feasible.

Keywords: remining; strategic minerals; construction material; tailings; remediation; resource management; resource technology

  • Invited lecture (Conferences) (Online presentation)
    Workshop Sustainable Mining, 06.10.2020, Lima, Peru

Publ.-Id: 32188

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

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

Satellite images have been widely used to characterize mineral alteration zones in surface rocks affected by hydrocarbons’ upward seepage. Likewise, magnetic surveys over oil fields have been employed for similar purposes. 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 pro- duced by these seeps and gain some knowledge about the processes involved in the subsequent mineral changes. Multispectral and hyperspectral satellite images showed three hydrocarbon-induced diagenetic anomalies (HIDAs) associated with undifferentiated clays and kaolinite, and low dolomite content. A simple weathering model was suggested combining the likely effects of the ascending seepage of oil and gas with the seasonal alternation of leaching and evaporation of meteoric waters. This model explains the magnetic enhancement with depth due to Fe oxides and sulfides’ formation by reducing and oxidizing events. A non-supervised Two-Step Cluster Analysis (TSCA) was applied to integrate geochemical and rock magnetic properties with satellite images. The input variables were log SIRM and proxies of undifferentiated clays and dolomite concentrations obtained from the band-ratio ASTER images. The TSCA yields three clusters associated with different alteration levels in the top and low (0.3–1 m) soils and sediments. By mapping the class membership of each sampling site, for both depth levels, it was possible to obtain a broad view of the synergistic change of these combined properties, not only over the whole extent of the study area but also from top to bottom of the weathered sequence. This case study illustrates the potential of such an integrated method as an oil exploration tool, and a means to assess the level and scope of the environmental impact produced by hydrocarbon seepage on terrestrial ecosystems.

Keywords: Satellite remote sensing; Spectral images; Spectral signature; Hydrocarbon seeps; Hydrocarbon-induced diagenesis; Rock magnetism; Weathered sequence; Two-step cluster analysis

Related publications

Publ.-Id: 32187

Spatial and temporal evolution of the Freiberg epithermal Ag-Pb-Zn District, Germany

Swinkels, L.; Schulz-Isenbeck, J.; Frenzel, M.; Gutzmer, J.; Burisch, M.

The Freiberg district hosts one of the largest series of epithermal polymetallic vein deposits in Europe. Systematic sampling during historic mining provides an excellent opportunity to study the anatomy of these epithermal systems. Detailed petrographic investigations, geochemical analyses and fluid inclusion studies were conducted on several vertical profiles within the Freiberg district to decipher mineralogical and geochemical zoning patterns. Six distinctive mineral associations have been recognized within the Freiberg epithermal veins; sphalerite-pyrite-quartz and galena-quartz-carbonate associations are most abundant in the central sector, as well as the deepest sections of veins on the periphery of the district. A high-grade sphalerite-Ag-sulfides-carbonate association occurs laterally between the central and peripheral sectors, and at intermediate depth in veins on the periphery. Shallow and peripheral zones are dominated by an exceptionally Ag-rich Ag-sulfides-quartz association, whereas the shallowest veins locally comprise Ag-poor stibnite-quartz and quartz-carbonate associations. Fluid inclusion assemblages returned low salinities (<6.0 % eq. w(NaCl)), and homogenization temperatures successively decrease from ~320°C associated with the proximal and deep sphalerite-pyrite-quartz association, to ~170°C related to the distal and shallow Ag-sulfides-quartz association.

  • Poster
    DMG virtual poster session, 30.11.-03.12.2020, Online, Deutschland

Publ.-Id: 32185

Mineralogy and Fluid Characteristics of the Waschleithe Zn skarn – a distal part of the Schwarzenberg mineral system, Erzgebirge, Germany

Reinhardt, N.; Frenzel, M.; Meinert, L. D.; Gutzmer, J.; Kürschner, T.; Burisch, M.

The Waschleithe skarn is situated in the northern sector of the Schwarzenberg District in the western Erzgebirge (Germany), a district which hosts several large polymetallic skarn deposits. The Waschleithe is a Zn-dominant skarn comprising abundant dark Mn-rich hedenbergite, minor grandite garnet and magnetite related to the prograde stage, as well as epidote, quartz, fluorite, amphibole, chlorite, ilvaite, and Mn-rich pyroxenoids related to the retrograde stage of skarn formation. Ore minerals are related to the early retrograde stage and include sphalerite, galena, chalcopyrite, pyrite as well as minor amounts of scheelite and cassiterite. Fluid inclusion homogenization temperatures range from ∼385 to 360°C and from ∼320 to 285°C for the prograde and retrograde skarn stages, respectively. Thus, late-stage cooling is proposed as the major controlling factor for sulfide mineral precipitation. Fluid salinities for both stages are very low (< 3 % eq. w[NaCl]) and all observed fluid inclusion assemblages show homogeneous liquid-vapor ratios. Formation pressures >25 MPa suggest a minimum depth of formation of approximately 3 km. Oxygen fugacity during prograde skarn formation was initially low and increased towards the late prograde stage. The late-Variscan Eibenstock granite is identified as the most likely source of the skarn-forming fluids. The recognition of the Waschleithe skarn as a distal Zn skarn has major implications for the understanding of the Schwarzenberg District mineral system and provides valuable information for exploration targeting.


Publ.-Id: 32184

Introduction - Impact of Mining and Raw Materials on Society

Frenzel, M.

Short presentation on the importance of mining and raw materials for society.

  • Lecture (others) (Online presentation)
    2D3Dscopy Workshop on CT for partners, 27.11.2020, Online, Germany

Publ.-Id: 32183

Modelling indium deportment in a polymetallic sulfide ore - The case of Neves-Corvo, Portugal

Frenzel, M.; Bachmann, K.; Carvalho, J.; Relvas, J.; Pacheco, N.; Gutzmer, J.

There is a general lack of reliable quantitative data on the mineralogy and spatial distribution of indium and other by-product metals in ore deposits. This contribution showcases a new approach to integrate by-product metals into geometallurgical assessments. As an example, it uses the distribution and deportment of indium at Neves-Corvo, a major European base-metal mine (Cu + Zn). This study is the first to develop a quantitative model of indium deportment in volcanic hosted massive sulfide ores, demonstrating how regularities in indium partitioning between different minerals can be used to predict its mineralogical deportment in individual drill-core samples. Bulk-ore assays of As, Cu, Fe, Pb, S, Sb, Sn, Zn, and In are found to be sufficient for reasonably accurate predictions. The movement of indium through the ore processing plants is well explained by its mineralogical deportment, allowing for specific mine and process planning. The novel methodologies implemented in this contribution should be of general applicability to the geometallurgical assessment of many other byproduct metals in polymetallic sulfide ores, including Ga, Ge, Mo, Re, Se, Te, as well as the noble metals.

Keywords: Critical metals; Indium

  • Invited lecture (Conferences) (Online presentation)
    MGEI Annual Meeting, 19.-29.10.2020, Online, Indonesia

Publ.-Id: 32182

Development of a sampling protocol for the resource definition of sulphidic Cu-Zn-Pb tailings in an industrial tailings storage facility

Blannin, R.; Frenzel, M.; Tolosana Delgado, R.; Gutzmer, J.

Fine-grained residues of ore processing, known as tailings, are an inevitable product of metal production. Such tailings are typically stored in dedicated Tailings Storage Facilities (TSF). The sedimentary-style deposition of tailings within the TSF results in a structure of sub-horizontal, internally graded layers which heterogeneously concentrate the minerals comprising the residues. Primary depositional structures may be overprinted by subsequent chemical redistribution of minerals and elements during chemical reactions and metal mobilisation. Sulphidic tailings are problematic in terms of the potential for generation of Acid and Metalliferous Drainage, while providing interesting prospects for extraction of recoverable metals. However, efforts to build accurate and reproducible geospatial models of TSFs are hampered by a lack of understanding of how to sample heterogeneous tailings materials in a way that allows the effective characterisation of both the horizontal and vertical variability. This study introduces a sampling protocol for the resource characterisation of TSFs, following the Theory of Sampling. The Davidschacht TSF in Freiberg, Germany, was used as a case study. The Davidschacht TSF was deposited between 1944 and 1969; it contains around 760,000 m3 of Cu-Zn-Pb sulphidic flotation residues originating from the processing of polymetallic hydrothermal vein ores of the Freiberg mining district. A historical drilling campaign of 10 drill holes through the whole depth of the tailings provided a basis for the study. A second drilling campaign of 68 drill holes to a depth of 3 m was carried out on a 30 m grid, and nested grids of 15 m and 7.5 m in the centre of the TSF. The drill cores were logged and a bulk sample was collected for each 1 m section. Representative samples, with 10% randomly selected for duplication, will be analysed with X-Ray Fluorescence for chemical composition and sieving and laser diffraction for particle size distribution. The modal mineralogy, mineral associations and mineral liberation of selected samples will be assessed with the Scanning Electron Microscope-based Mineral Liberation Analyser. A detailed geospatial model of the surface zone of the tailings will be constructed to assess the intrinsic horizontal variability of the TSF. Comparison with the 3D model produced by the previous deep drilling campaign will determine if the sampling and modelling was sufficient to account for the variability of the tailings.

  • Open Access Logo Lecture (Conference) (Online presentation)
    European Geosciences Union General Assembly 2020, 04.05.2020, Wien, Austria

Publ.-Id: 32181

Data from a pilot plant experiment for the processing of a complex tin skarn ore - 19.11.2018

Schach, E.; Padula, F.; Buchmann, M.; Möckel, R.; Ebert, D.; Pereira, L.; Kern, M.; Leißner, T.; Pashkevich, D.; Sousa, R.; Bremerstein, I.; Breuer, B.; Oliver, K.; Seltmann, R.; Reimer, W.; Wotruba, H.; Filippov, L.; Peuker, U.; Rudolph, M.; Broadbent, C.; Roscher, M.; van den Boogaart, K. G.

This data set derives from a pilot plant campaign for the beneficiation of a complex tin bearing skarn ore, including different separation and classification steps. The aim of the pilot plant test work was to prove a flowsheet that had been developed based on detailed geometallurgical analysis and results from the research projects AFK (Aufbereitung feinkörniger Komplexerze, BMBF grant number 033R128) and FAME (European Union grant 641650) to produce a cassiterite concentrate for tin production, and further preconcentrates for iron, zinc, copper, indium, and arsenic. The tin mineralization is partially well localized in cassiterite, but also partially finely disseminated and thus unrecoverable as minor components in other minerals. The iron is located in magnetic and nonmagnetic iron oxides sometimes intergrown with cassiterite. Therefore, iron concentrates are recovered at larger grain sizes but need a further tin recovery step not implemented in the reported experiment. The other elements are mainly deported in sulfides, which are bulk recovered in a flotation step. A subsequent selective flotation is needed to recover them individually. This selective flotation is, however, not part of the reported experiment. The two tin concentrates recovered from the shaking table should be considered as preconcentrates, that can be enriched further e.g. through multi-stage gravity separation.

The motivation for this data set is to provide a consistent basis for the application of new particle based geometallurgical methods enabled by automated mineralogy (e.g. Buchmann et al. 2018; Schach et al. 2019; Buchmann et al. 2020; Pereira et al. 2020).

In addition, it should also allow for the comparison and evaluation of different analytical methods, which were used during the pilot plant experiments to generate a validated data set for the whole plant and to correlate different result from various methods. This is the basis for further investigations enabling the application of various analyzing methods in a synergetic way. Those synergies can help in the future to compensate drawbacks of certain methods by an adequate combination of multiple approaches.

This repository includes raw data and processed data from November 19, 2018. The following data is included:

  • X-ray fluorescence spectroscopy (XRF)
  • X-ray diffraction (XRD)
  • Automated Mineralogy (MLA)
  • The balanced mass flows and element/mineral grades for the XRF- and the MLA data
  • External certified analysis including different inductive coupled plasma (ICP) and XRF methods from ALS
  • R scripts for the mass balance

Please find further information in the "supplementary information" file

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2021-01-06
    DOI: 10.14278/rodare.714
    License: CC-BY-4.0


Publ.-Id: 32180

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