Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Condensed matter magneto-optical investigations can be a powerful probe of a material's microscopic magnetoelectric properties. This is because subtle interactions between electric and magnetic multipoles on a crystal lattice show up in predictable and testable ways in a material's optical response tensor, which dictates the polarization state and absorption spectrum of propagating electromagnetic waves. Magneto-optical techniques are therefore strong complements to probes such as neutron scattering, particularly when spin-lattice coupling effects are present. Here we perform a magneto-optical investigation of vibronic spin-lattice coupling in the magnetically frustrated pyrochlore Tb2Ti2O7. Coupling of this nature involving quadrupolar mixing between the Tb3+ electronic levels and phonons in Tb2Ti2O7 has been a topic of debate for some time. This is particularly due to its implication for describing the exotic spin-liquid phase diagram of this highly debated system. A manifestation of this vibronic effect is observed as splitting of the ground and first excited crystal field doublets of the Tb3+ electronic levels, providing a fine structure to the absorption spectra in the terahertz (THz) frequency range. In this investigation, we apply a static magnetic field along the cubic [111] direction while probing with linearly polarized THz radiation. Through the Zeeman effect, the magnetic field enhances the splitting within the low-energy crystal field transitions revealing new details in our THz spectra. Complementary magneto-optical quantum calculations including quadrupolar terms show that indeed vibronic effects are required to describe our observations at 3 K. A further prediction of our theoretical model is the presence of a novel magneto-optical birefringence as a result of this vibronic process. Essentially, spin-lattice coupling within Tb2Ti2O7 may break the optical isotropy of the cubic system, supporting two different electromagnetic wave propagations within the crystal. Together our results reveal the significance of considering quadrupolar spin-lattice effects when describing the spin-liquid ground state of Tb2Ti2O7. They also highlight the potential for future magneto-optical investigations to probe complex materials where spin-lattice coupling is present and reveal new magneto-optical activity in the THz range.

In this work, for the first time, fragmentation and joining of tungsten oxide (WO3) nanorods induced by a broad ion beam are reported. Although at low energy (5 keV) and moderate ion fluence, nanorods fragment into smaller pieces along the length, at higher ion energies (50-100 keV), a contrary process occurs, which leads to the joining of the nanorods. A state-of-the-art ion-solid interaction simulation, namely, TRI3DYN, has been invoked to explore the possible mechanisms that reveal subtle contributions of surface defects, ion-beam mixing, and sputtering. High-resolution electron microscopy, photoluminescence study, and X-ray photoelectron spectroscopy support the observed results and proposed mechanisms. Such modifications have interesting effects on the electrical conductivity of the nanorod assembly. The change in sample color upon ion irradiation from initial white to yellow, light blue, deep blue, light green, and cyan shows an excellent and reversible chromatic response of tungsten oxide nanorods to irradiation. Such a property can be exploited to fabricate radiation sensors. The fragmentation and joining at different energy scales have essential implications in nanodevice fabrication through the bottom-up approach as well as for the development of fusion reactors.

2Laboratory for Radiopharmacy, KU Leuven, Leuven, Belgium
Introduction: In pathological conditions, the up-regulation of cannabinoid receptors type 2 (CB2) receptors has been reported in association with traumatic brain injury (TBI), neurodegeneration and cancer.[1] Up to date, only [11C]NE40 was evaluated in human subjects as PET tracer for the CB2 receptors. Recently, we reported the development of [18F]JHU94620, a highly affine and selective 18F-labeled CB2 radiotracer (Ki(hCB2) = 0.4 nM, Ki(hCB1) = 380 nM). However, this radioligand suffers from low metabolic stability in-vivo (36% intact tracer detected at 30 min p.i. in brain of CD1 mice).[2] Here, we describe the development of the deuterated analogues [18F]JHU94620-d4 and [18F]JHU94620-d8 as well as their in vitro and in-vivo evaluation in rats.
Methods: The precursors for radiofluorination were obtained by coupling 4,5-dimethylthiazol-ylidene-2,2,3,3-tetramethylcyclopropane-1-carboxamide with either d4 or d8 1,4-butanediol-bistosylate. The radiosynthesis of the deuterated [18F]JHU94620 analogues was performed in presence of Kryptand K2.2.2. and K2CO3. The metabolic stability of the new tracers was evaluated at 30 min p.i. in plasma, brain and spleen of healthy CD1 mice. The affinity and specificity toward the CB2 receptor was evaluated by in vitro autoradiography and binding experiments. Additionally, we evaluated the [18F]JHU94620-d8 uptake in vivo by PET-studies into the spleen of healthy rats and in a rat model overexpressing the hCB2 in the right striatum.[3]
Results: [18F]JHU94620-d4 and -d8 were obtained in moderate radiochemical yields of about 10% and high radiochemical purities (>99%). Preliminary results revealed a considerable improved metabolic stability of both deuterated [18F]JHU94620 analogues with 80% intact tracer in the brain at 30 min. p.i. in mice. In-vitro evaluation of [18F]JHU94620-d8 revealed a KD(rCB2) = 0.36 nM (SPRD rats spleen homogenates) and KD(hCB2) = 2.72 nM (hCB2-CHO cell membrane homogenate) as well as specific binding in mice and rat spleen autoradiography. PET studies with [18F]JHU94620-d8 revealed a rCB2 specific spleen uptake, which could be blocked by the CB2 agonist GW405833. Furthermore, a specific and reversible uptake of [18F]JHU94620-d8 revealed a constant SUV of 6.7±0.3 from 6 to 60 min p.i. in the rat model overexpressing the hCB2 in the right striatum with a high signal to background ratio shown by a SUVr (right striatum-to-cerebellum) of 43±7at 60 min p.i..
Conclusion: [18F]JHU94620-d8 is a new PET tracer with improved metabolic stability and excellent ability to image the CB2 receptors in-vivo. Its further evaluation is underway.

PURPOSE Given the poor results using hypofractionated radiotherapy for early breast cancer, a dose of 50 Gy in 25 fractions (fr) has been the standard regimen used by the Danish Breast Cancer Group (DBCG) since 1982. Results from more recent trials have stimulated a renewed interest in hypofractionation, and the noninferiority DBCG HYPO trial (ClincalTrials.gov identifier: NCT00909818) was designed to determine whether a dose of
40 Gy in 15 fr does not increase the occurrence of breast induration at 3 years compared with a dose of 50 Gy in 25 fr.

PATIENTS AND METHODS One thousand eight hundred eighty-two patients .40 years of age who underwent breast-conserving surgery for node-negative breast cancer or ductal carcinoma in situ (DCIS) were randomly assigned to radiotherapy at a dose of either 50 Gy in 25 fr or 40 Gy in 15 fr. The primary end point was 3-year grade 2-3 breast induration assuming noninferiority regarding locoregional recurrence.

RESULTS A total of 1,854 consenting patients (50 Gy, n 5937; 40 Gy, n 5917) were enrolled from 2009-2014 from eight centers. There were 1,608 patients with adenocarcinoma and 246 patients with DCIS. The 3-year rates of induration were 11.8% (95% CI, 9.7% to 14.1%) in the 50-Gy group and 9.0% (95% CI, 7.2% to 11.1%) in the 40-Gy group (risk difference, 22.7%; 95% CI, 25.6% to 0.2%; P 5 .07). Systemic therapies and radiotherapy boost did not increase the risk of induration. Telangiectasia, dyspigmentation, scar appearance, edema, and pain were detected at low rates, and cosmetic outcome and patient satisfaction with breast appearance were high with either no difference or better outcome in the 40-Gy cohort compared with the 50-Gy cohort. The 9-year risk of locoregional recurrence was 3.3% (95% CI, 2.0% to 5.0%) in the 50-Gy group and 3.0% (95% CI, 1.9% to 4.5%) in the 40-Gy group (risk difference, 20.3%; 95% CI, 22.3% to 1.7%). The 9-year overall survival was 93.4% (95% CI, 91.1% to 95.1%) in the 50-Gy group and 93.4% (95% CI, 91.0% to 95.2%)
in the 40-Gy group. The occurrence of radiation-associated cardiac and lung disease was rare and not influenced by the fractionation regimen.

CONCLUSION Moderately hypofractionated breast irradiation of node-negative breast cancer or DCIS did not result in more breast induration compared with standard fractionated therapy. Other normal tissue effects were minimal, with similar or less frequent rates in the 40-Gy group. The 9-year locoregional recurrence risk was low.

The astrophysical 6Li(p,γ)7Be reaction occurs during Big Bang nucleosynthesis and the pre-main sequence and main sequence phases of stellar evolution. The low-energy trend of its cross section remains uncertain, since different measurements have provided conflicting results. A recent experiment reported a resonancelike structure at center-of-mass energy 195 keV, associated to a positive-parity state of 7Be. The existence of such resonance is still a matter of debate. We report a new measurement of the 6Li(p,γ)7Be cross section performed at the Laboratory for Underground Nuclear Astrophysics, covering the center-of-mass energy range E=60–350 keV. Our results rule out the existence of low-energy resonances. The astrophysical S-factor varies smoothly with energy, in agreement with theoretical models.

Olive-green single crystals of ammonium octafluoridoneptunate(IV), (NH₄)₄[NpF₈], were obtained by converting NpO₂ to a green neptunium tetrafluoride hydrate with hydrofluoric acid and subsequent treatment of the fluoride with an aqueous NH₄F solution. The crystal structure of the compound was determined by single-crystal X ray diffraction and observed to be isotypic to the uranium analogue. In (NH₄)₄[NpF₈], molecular [NpF₈]⁴‾ anions, which can either be described as a distorted square-antiprism or a bicapped trigonal prism, are present which are bound to the NH₄⁺ ions via N−H∙∙∙F hydrogen bonds. Quantum-chemical calculations of [MF₈]⁴‾ anions show that the M−F bonds are highly ionic and the energy differences between different ligand arrangements likely can be overcome by lattice energies of different crystal structures in the solid state.

Focused Ion Beam Induced Deposition (FIBID) is a nanopatterning technique that makes use of a focused beam of charged ions to decompose a gaseous precursor. So far, the flexible patterning capabilities of FIBID have been widely exploited in the fabrication of superconducting nanostructures, using the W(CO) 6 precursor mostly in combination with a focused beam of Ga+ ions. Here, the fabrication and characterization of superconducting in-plane tungsten-carbon (W-C) nanostructures by He+ FIBID of the W(CO)6 precursor is reported. A virtually unattainable for Ga+ FIBID patterning resolution of 10 nm has been achieved. When the nanowires are patterned with widths of 20 nm and above, the deposited material is superconducting below 3.5 – 4 K. In addition, 60 and 90 nm-wide nanostructures have been found to sustain long-range controlled non-local superconducting vortex transfer along 3 μm. Overall, these findings strengthen the capabilities of He+ FIBID of W-C in the growth and patterning of in-plane superconducting nanodevices.

Copper and cast iron are potential materials for the storage canisters of high-level radioactive waste. We designed slurry-experiments for analyzing the microbial influence on the corrosion process of these metals. These slurry experiments contain the Bavarian B25 bentonite, synthetic Opalinus Clay pore water or diluted cap rock solution as well as copper- or cast iron plates in various combinations. During an incubation time of 400 days under anaerobic conditions at 37 °C cast iron plates corrode very fast. The respective metal surfaces show the formation of iron oxides and –carbonates which could form a passivating film that protects the cast iron from further corrosion.

Computational Fluid Dynamics (CFD) simulations of the solid-liquid flow in stirred tanks are feasible with appropriate closure models. However, no systematic assessment of different models have appeared because of lacking validation data. The present study accumulates a "CFD-grade" database on single-phase and two-phase flows experiments in a stirred tank (diameter=90mm). The velocity fields of the liquid and the solid phase are measured with Particle Image Velocimetry and Particle Shadow Velocimetry, respectively. The experiments cover a range of parameters as density ratio (ρ_S / ρ_L = 1.1...2.5), particle diameter (63 μm...500 μm), solid volume fraction (0.025vol%...0.1vol%) and impeller rotation speed (650rpm...1500 rpm). The mean and fluctuating liquid and solid velocities are obtained as time and angle-resolved averaging, as well as the local solid fraction. The experimental data of the single phase flow is compared with CFD simulations and show a good predictions. A systematic assessment of CFD models for solid-liquid flows will appear as a sequel.

Small pores zeolites are successfully employed as catalysts, sorbents and molecular sieves. Their physiochemical properties can be improved by modifying their extraframework (EF) cation content via ion exchange. In this study, we investigate the crystal structure of a Cd-exchanged levyne (LEV) intergrown with erionite (ERI) by combining Single Crystal X-ray Diffraction (SCXRD), Molecular Dynamic simulations (MD) and Extended X-ray Absorption Fine- Structure analysis spectroscopy (EXAFS). Data obtained from the different techniques, consistently indicated that Cd2+ distribute in an almost ordered fashion in LEV. In contrast, strong disorder of the EF species (Cd2+ and H2O) is observed in the ERI cavities. In the latter, Cd2+ form aqueous complexes that are more mobile in comparison towith respect Cd2+ in LEV, where it bonds to H2O and framework-oxygen atoms. The formation of Cd-clusters is excluded based on EXAFS analysis. Finally, to discriminate between thermal and static disorder, we proposed a new approach based on a combined MD and geometry optimization analysis.

Neben abiotischen Faktoren können auch mikrobielle Prozesse einen Einfluss auf die Langzeitsicherheit eines nuklearen Endlagers haben. Darum wird aktuell im Rahmen des Projekts iCROSS die mikrobiellen Diversität in dem Verfüllmaterial Bentonit untersucht und die mikrobielle Aktivität mittels Mikrokosmosexperimenten bestimmt. Weitere Experimente befassen sich außerdem mit der mikrobiell beeinflussten Korrosion von Behältermaterialien. Letzteres ist auch von hoher Relevanz für andere technische Anlagen und Prozesse. Aus diesem Grund werden in dem Vortrag außerdem Möglichkeiten für weitere Projektideen aufgezeigt und diskutiert.

Lanthanide (Ln) exposure poses a serious health risk to animals and humans. In this study, we investigated the effect of 10-9 - 10-3 M La, Ce, Eu, and Yb exposure onto the viability of rat renal NRK-52E cells in dependence on Ln concentration, exposure time, and composition of the cell culture medium. Especially, the influence of fetal bovine serum (FBS) and citrate onto Ln cytotoxicity, solubility, and speciation was investigated. For this, in vitro cell viability studies using the XTT assay and fluorescence microscopic investigations were combined with solubility and speciation studies using TRLFS and ICP-MS, respectively. The theoretical Ln speciation was predicted using thermodynamic modeling. All Ln exhibit a concentration- and time-dependent effect on NRK-52E cells. FBS is the key parameter influencing both Ln solubility and cytotoxicity. We demonstrate that FBS is able to bind Ln3+ ions, thus, promoting solubility and reducing cytotoxicity after Ln exposure for 24 and 48 h. In contrast, citrate addition to the cell culture medium has no significant effect on Ln solubility and speciation nor cytotoxicity after Ln exposure for 24 and 48 h. However, a striking increase of cell viability is observable after Ln exposure for 8 h. Out of the four Ln elements under investigation, Ce is the most effective. Results from TRLFS and solubility measurements correlate well to those from in vitro cell culture experiments. In contrast, results from thermodynamic modeling do not correlate to TRLFS results, hence, demonstrating that big gaps in the database render this method, currently, inapplicable for the prediction of Ln speciation in cell culture media. Finally, this study demonstrates the importance and the synergistic effects of combining chemical and spectroscopic methods with cell culture techniques and biological methods.

The Institute of Fluid Dynamics at the HZDR operates ultrafast electron beam X-ray CT scanners, a.k.a. ROFEX-CT scanners, that are used to visualize rapidly moving two-phase gas-liquid scenarios in technical devices with an imaging rate of up to 8,000 images per second. This means, radiographic projections are acquired from different angular positions of the two-phase flow and reconstruction algorithms, e.g. filtered back projection or algebraic reconstruction technique, are applied to obtain a stack of cross-sectional images as a sequence of time. The scanners can be operated in single or dual-plane mode. The presentation highlights the construct that is developed to start OS-independent data reconstruction jobs at HEMERA.

We have investigated the interaction of the actinide Cm(III) and its lanthanide homologue Eu(III) with cells of Brassica napus in suspension. This study combines biochemical techniques (plant cell response) with spectroscopic experiments to determine the chemical speciation of the metals in contact with the cells. Experiments conducted over a period of 7 d showed that B. napus cells were able to bioassociate both potentially toxic metals, with results confirming up to 0.58 µmol Eu/gfresh cells and 1.82 µmol Cm/gfresh cells at the lowest provided metal concentration. For Cm(III), a biosorption process could be identified as soon as 5 h post-exposure with 73±4% of the Cm(III) bioassociated. Additional luminescence spectroscopy results based on UV and site-selective excitation confirmed the existence of three Cm(III)/Eu(III), M(III), species in both the supernatants and cells. The findings detailed herein support that M(III) coordination to two kinds of carboxyl groups and phosphate groups.

This project provides a framework for fast memory managers on many core accelerators. It is based on alpaka to run on many different accelerators and implements the ScatterAlloc algorithm.

In recent years, molybdenum disulfide (MoS2) has been investigated due to its unique electronic, optical, and mechanical properties with a variety of applications. Sulfurization of pre-deposited MoO3 layers is one of the methods of the preparation of large-area MoS2 thin films. The MoO3 layers have been grown on c-sapphire substrates, using two different techniques (rf sputtering, pulsed laser deposition). The films were subsequently annealed in vapors of sulfur at high temperatures what converted them to MoS2 films. The quality of MoS2 is strongly influenced by the properties of the precursor MoO3 layers. The pre-deposited MoO3, as well as the sulfurized MoS2, have been characterized by several techniques including Raman, Rutherford backscattering spectroscopy, atomic force microscopy, scanning electron microscopy, and X-ray diffraction. Here we compare two types of MoS2 films prepared from different MoO3 layers to determine the most suitable MoO3 layer properties providing good quality MoS2 films for future applications.

The presentation is aimed at introducing diffraction techniques and their applications in the field of structural nuclear materials. After a brief introduction, three selected experimental techniques are presented in more detail. These are X-ray line profile analysis (XLPA), electron backscatter diffraction (EBSD) and small-angle neutron scattering (SANS). XLPA is applied to derive microstructure parameters such as crystallite size, dislocation density and twin probability of a nanostructured high-entropy alloy processed by means of high pressure torsion. EBSD is shown to be useful for the characterization of the bainitic microstructure in terms of subunits of the prior austenite grains and their orientation relationship with the parent phase. As an example for the application of SANS, the effects of neutron flux and neutron fluence on the volume fraction and mean size of irradiation-induced solue atom clusters are characterized.

We present a frequency and magnetic field dependent investigation of ordered arrangements of 20 nm mag-netic nanoparticles (MNPs) consisting of magnetite (Fe3O4) by employing micro Brillouin light scatteringmicroscopy. We utilized electron beam lithography to prepare hexagonally arranged, circularly shaped MNP-assemblies consisting of a single layer of MNPs using a variant of the Langmuir-Blodgett technique. Bycomparing the results with non-structured, layered superlattices of MNPs, further insight into the influenceof size and geometry of the arrangement on the collective properties is obtained. We show that at low staticexternal field strengths, two signals occur in frequency dependent measurements for both non-structured andstructured assemblies. Enlarging the static external field strength leads to a sharpening of the main signal,while the satellite signal decreases in its intensity and increases in its linewidth. The occurrence of multiplesignals at low external field strengths is also confirmed by sweeping the static external field and keeping theexcitation frequency constant. Micromagnetic simulations unravel the origin of the different signals and theirdependence on the static external field strength, enabling an interpretation of the observed characteristics interms of different local environments of an MNPs forming the MNP assembly.

This study presents an approach to the selection of optimal energy group structures for multi-group nodal diffusion analyses of Sodium-cooled Fast Reactor cores. The goal is to speed up calculations, particularly in transient calculations, while maintaining an acceptable accuracy of the results.
In Part I of the paper, possible time-savings due to collapsing of energy groups are evaluated using 24-group energy structure as a reference. Afterwards, focusing on energy structures with a number of groups leading to significant calculation speedups, optimal grid configurations are identified. Depending on a number of possible energy grid configurations to explore, the optimization is conducted by either a direct search or applying the simulated annealing method. Speedup and optimization studies are performed on a selected case of the Superphénix static neutronic benchmark by using the nodal diffusion DYN3D code. The results demonstrate noticeable improvements in DYN3D performance with a marginal deterioration of the accuracy.

We show the synthesis of an in vivo stable mercury compound with functionality suitable for radiopharmaceuticals. The designed cyclic bisarylmercury was based on the water tolerance of organomercurials, higher bond dissociation energy of Hg-Ph to Hg-S, and the experimental evidence that acyclic structures suffer significant cleavage of one of the Hg-R bonds. The bispidine motif was chosen for its in vivo stability, chemical accessibility, and functionalization properties. Radionuclide production results in 197(m)HgCl2(aq), so the desired mercury compound was formed via a water-tolerant organotin transmetallation. The Hg-bispidine compound showed high chemical stability in tests with an excess of sulphur-containing competitors and high in vivo stability, without any observable protein interaction by human serum assay, and good organ clearance demonstrated by biodistribution and SPECT studies in rats. In particular no retention in the kidneys typical of unstable mercury compounds. The natHg analogue allowed full characterization by NMR and HRMS.

The development of high-density magnetic recording media is limited by superparamagnetism in very small ferromagnetic crystals. Hard magnetic materials with strong perpendicular anisotropy offer stability and high recording density. To overcome the difficulty of writing media with a large coercivity, heat-assisted magnetic recording was developed, rapidly heating the media to the Curie temperature T_c before writing, followed by rapid cooling. Requirements are a suitable T_c, coupled with anisotropic thermal conductivity and hard magnetic properties. Here, Rh₂CoSb is introduced as a new hard magnet with potential for thin-film magnetic recording. A magnetocrystalline anisotropy of 3.6 MJ m⁻³ is combined with a saturation magnetization of μ₀M_s = 0.52 T at 2 K (2.2 MJ m⁻³ and 0.44 T at room temperature). The magnetic hardness parameter of 3.7 at room temperature is the highest observed for any rare-earth-free hard magnet. The anisotropy is related to an unquenched orbital moment of 0.42 μ_B on Co, which is hybridized with neighboring Rh atoms with a large spin–orbit interaction. Moreover, the pronounced temperature dependence of the anisotropy that follows from its T_c of 450 K, together with a thermal conductivity of 20 W m⁻¹ K⁻¹, make Rh₂CoSb a candidate for the development of heat-assisted writing with a recording density in excess of 10 Tb in.⁻².

The Helmholtz-Center Dresden-Rossendorf operates a superconducting electron linear accelerator (named ELBE radiation source) as a driver for secondary beams of electromagnetic radiation, neutrons, and positrons. The combination of high-intensity secondary beams, superior timing resolution, and adjustable beam repetition rates allows performing experiments, which are hardly possible using alternative technologies. The facility runs as a dedicated user facility thus serving an international community. Applications range from tunable coherent infra-red radiation from an Free-Electron Laser, coherent super-radiant THz radiation with sub-ps timing, high-energy gamma-rays and neutrons for nuclear physics to secondary positron beams for materials research.
Several recent scientific results will be presented and plans for a successor, the Dresden Advanced Light Infrastructure (DALI), will be shown.

The book chapter is about the geology of rare earth elements, their mineral carrier as well as secondary raw materials.

Material sputtered from CaF2 single crystals by 180 MeV Au ions impinging at different incidence angles were collected on high-purity amorphous C-coated Cu grids and Si100 wafer catcher surfaces over a broad angular range. These catcher surfaces were characterized complementary by transmission electron microscopy, atomic force microscopy and medium energy ion scattering, revealing the presence of a distribution of partially buried CaF2 nanoparticles in conjunction to a thin layer of deposited CaF2 material. Particle size distributions do not follow simple power laws and depend on the angles of ion incidence and particle detection. It is shown that the particle ejection is directly related to the jet-like component of sputtering, previously observed in ionic crystals, contributing significantly to the total yield. This contribution enhances as the impinging ions approach grazing incidence. Possible scenarios for the emission of particles are discussed in light of these observations.

Background: Craniofacial surgery is the standard of treatment for children with moderate to severe trigonocephaly. However, assessing the risk of suboptimal neurodevelopment and added value of surgery is difficult in individual cases. In this study we aim to address the hypothesis that brain development is restricted in trigonocephaly patients by investigating cerebral blood flow in the frontal lobe.
Methods: Between 2018 and 2020, we prospectively included trigonocephaly patients for whom a surgical correction was considered in an MRI study measuring cerebral perfusion with arterial spin labeling (ASL). The mean value of cerebral blood flow (CBF) in the frontal lobe was calculated for each subject and compared between the trigonocephaly patients and healthy controls.
Results: MRI scans of 36 trigonocephaly patients (median age 0.5y, IQR 0.3, 11 females) were included and compared with 16 controls without cerebral pathology (median age 0.83y, IQR 0.56, 10 females). The mean CBF values in the frontal lobe of the trigonocephaly patients (73.0 ml/100g/min) did not appear to be significantly different in comparison with controls (70.5 ml/100g/min, p = 0.6479). The superior, middle, and inferior part of the frontal lobe showed no significant differences either.
Conclusions: Before surgery, the frontal lobe of trigonocephaly patients aged under 18 months old has a normal CBF. In addition to the previously reported very low prevalence of papilledema or impaired skull growth, this finding further supports our hypothesis that craniofacial surgery for trigonocephaly is rarely indicated for signs of raised intracranial pressure.

In this invited comment we discuss the results of the manuscript of Yan et al. EbioMedicine, with title "Incremental prognostic value and underlying biological pathways of radiomics patterns in medulloblastoma"

Purpose: To develop and validate a CT-based radiomics signature for the prognosis of loco-regional tumour control (LRC) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) treated by primary radiochemotherapy (RCTx) based on retrospective data from 6 partner sites of the German Cancer Consortium – Radiation Oncology Group (DKTK-ROG).
Material and methods: Pre-treatment CT images of 318 patients with locally advanced HNSCC were collected. Four-hundred forty-six features were extracted from each primary tumour volume and then filtered through stability analysis and clustering. First, a baseline signature was developed from demographic and tumour-associated clinical parameters. This signature was then supplemented by CT imaging features. A final signature was derived using repeated 3-fold cross-validation on the discovery cohort. Performance in external validation was assessed by the concordance index (C-Index). Furthermore, calibration and patient stratification in groups with low and high risk for loco-regional recurrence were analysed.
Results: For the clinical baseline signature, only the primary tumour volume was selected. The final signature combined the tumour volume with two independent radiomics features. It achieved moderately good discriminatory performance (C-Index [95% confidence interval]: 0.66 [0.55-0.75]) on the validation cohort along with significant patient stratification (p=0.005) and good calibration.
Conclusion: We identified and validated a clinical-radiomics signature for LRC of locally advanced HNSCC using a multi-centric retrospective dataset. Prospective validation will be performed on the primary cohort of the HNprädBio trial of the DKTK-ROG once follow-up is completed.

Magneto‐ionics, understood as voltage‐driven ion transport in magnetic materials, has largely relied on controlled migration of oxygen ions. Here, we demonstrate room‐temperature voltagedriven nitrogen transport (i.e., nitrogen magneto‐ionics) by electrolyte‐gating of a CoN film.
Nitrogen magneto‐ionics in CoN is compared to oxygen magneto‐ionics in Co3O4. Both materials are nanocrystalline (face‐centered‐cubic structure) and show reversible voltage‐driven ON‐OFF ferromagnetism. In contrast to oxygen, nitrogen transport occurs uniformly creating a plane‐wavelike migration front, without assistance of diffusion channels. Remarkably, nitrogen magnetoionics requires lower threshold voltages and exhibits enhanced rates and cyclability. This is due to the lower activation energy for ion diffusion and the lower electronegativity of nitrogen compared to oxygen. These results may open new avenues in applications such as brain‐inspired computing or iontronics in general.

Efficient photoelectrocatalytic (PEC) water splitting could be the solution for environmental and energy problems on planet Earth. Here, we explore 2D palladium thiophosphate Pd3(PS4)2, which is a promising photocatalyst absorbing light in the visible range. We obtain a few-layer Pd3(PS4)2 through lithium-assisted exfoliation from the bulk phase and characterize it employing Raman spectroscopy, XPS, AFM, and STM combined with DFT calculations. The measured band gap for as-obtained few-layer Pd3(PS4)2 is 2.57 eV (indirect) and its band edges span the electrochemical potentials of the hydrogen and oxygen evolution reactions. The performance in the water-splitting reaction is studied under acidic, neutral, and alkaline conditions under violet irradiation at 420 nm. 2D palladium phosphochalcogenides semiconductor with bifunctional electrocatalytic and photoelectrocatalytic properties. Our results show competitive performance compared with industrial Pt/C catalysts for solar-driven water splitting under acidic and alkaline conditions.

Highly ordered titanium oxide films grown on the Pt3Ti(111) alloy surface have been utilized for the controlled immobilization and the tip-induced electric field triggered electronic manipulation of nanoscopic W3O9 clusters. Depending on the operating conditions two different stable oxide phases z’-TiOx and w’-TiOx were produced. These phases show a strong effect on the adsorption characteristics and reactivity of W3O9 clusters that are formed as a result of thermal evaporation of WO3 powder on the complex TiOx/Pt3Ti(111) surfaces under ultra-high vacuum conditions. The physisorbed tritungsten nonaoxides were found as isolated single units located on metallic attraction points or as supramolecular self-assemblies with a W3O9-capped hexagonal scaffold of W3O9 units. By applying the scanning tunneling microscopy to the W3O9(W3O9)6 structures individual units undergo a tip induced reduction to W3O8. At elevated temperatures agglomeration and the growth of large WO3 islands, which thickness is strongly limited to a maximum of two unit cells, is observed. The findings boost progress toward the template-directed nucleation, growth, networking and charge state-manipulation of functional molecular nanostructures at surfaces using operando techniques.

In van der Waals heterostructures of two-dimensional transition-metal dichalcogenides (2D TMDCs) electron and hole states are spatially localized in different layers forming long-lived interlayer excitons. Here, we have investigated, from first principles, the influence of additional electron or hole layers on the electronic properties of a MoS2/WSe2 heterobilayer (HBL), which is a direct band gap material. Additional layers modify the interlayer hybridization, mostly affecting the quasiparticle energy and real-space extend of hole states at the G and electron states at the Q valleys. For a sufficient number of additional layers, the band edges move from K to Q or G, respectively. Adding electron layers to the HBL leads to more delocalized Q states, while G states do not extend much beyond the HBL, even when more hole layers are added. These results suggest a simple and yet powerful way to tune band edges and the real-space extend of the electron and hole wave function in TMDC heterostructures, strongly affecting the lifetime and dynamics of interlayer excitons.

A promising strategy for new electrically conductive coordination polymers is the combination of d10 metal ions, which tolerate short metal···metal distances, with dithiolene linkers, known for their “non-innocent” redox behavior. This study explores the coordination chemistry of 2,3-pyrazinedithiol (H2pdt) towards Cu+ and Ag+ ions, highlighting similarities and differences. The synthetic approach, starting with the fully protonated ligand, allowed the isolation of a homoleptic bis(dithiolene) complex with formal CuI atoms, [Cu(H2pdt)2]Cl (1). This complex was further transformed to a one-dimensional coordination polymer with short metal···metal distances, 1D[Cu(Hpdt)] (2Cu). The larger Ag+ ion directly built up a very similar coordination polymer 1D[Ag(Hpdt)] (2Ag), without any appearance of an intermediate metal complex. The coordination polymer 1D[Cu(H2pdt)I] (4), like complex 1, bears fully protonated H2pdt ligands in their dithione form. Upon heating, both compounds underwent auto-oxidation coupled with a dehydrogenation of the ligand to form the open shell neutral copper(II) complex [Cu(Hpdt)2] (3) and the coordination polymer 1D[Cu2I2(Hpdt)(H2pdt)] (5), respectively. For all presented compounds, crystal structures are discussed in-depth. Furthermore, properties of 1, 3, as well as of the three one-dimensional coordination polymers 2Ag, 2Cu and 4, were investigated by UV-Vis-NIR spectroscopy, cyclic voltammetry, and variable temperature magnetic susceptibility, and DC-conductivity measurements. The experimental results are compared and discussed with the aid of DFT simulations.

Image guidance using in-beam real-time magnetic resonance (MR) imaging is expected to improve the targeting accuracy of proton therapy for moving tumors, by reducing treatment margins, detecting inter- and intrafractional anatomical changes and enabling beam gating. The aim of this study was to quantitatively characterize the static magnetic field and image quality of a 0.22 T open MR scanner that has been integrated with a static proton research beamline. The magnetic field and image quality studies were performed using high-precision magnetometry and standardized diagnostic image quality assessment protocols, respectively. The magnetic field homogeneity was found to be typical of the scanner used (98 ppm). Operation of the beamline magnets changed the central resonance frequency and magnetic field homogeneity by a maximum of 16 Hz and 3 ppm, respectively. It was shown that the in-beam MR scanner features sufficient image quality and influences of simultaneous irradiation on the images are restricted to a small sequencedependent image translation and a minor reduction in signalto-noise ratio. Nevertheless, specific measures have to be taken to minimize these effects in order to achieve accurate and reproducible imaging which is required for a future clinical application of MR integrated proton therapy.

Background

Asphericity (ASP) of the primary tumor’s metabolic tumor volume (MTV) in FDG-PET/CT is independently predictive for survival in patients with non-small cell lung cancer (NSCLC). However, comparability between PET systems may be limited. Therefore, reproducibility of ASP was evaluated at varying image reconstruction and acquisition times to assess feasibility of ASP assessment in multicenter studies.

Methods

This is a retrospective study of 50 patients with NSCLC (female 20; median age 69 years) undergoing pretherapeutic FDG-PET/CT (median 3.7 MBq/kg; 180 s/bed position). Reconstruction used OSEM with TOF4/16 (iterations 4; subsets 16; in-plane filter 2.0, 6.4 or 9.5 mm), TOF4/8 (4 it; 8 ss; filter 2.0/6.0/9.5 mm), PSF + TOF2/17 (2 it; 17 ss; filter 2.0/7.0/10.0 mm) or Bayesian-penalized likelihood (Q.Clear; beta, 600/1750/4000). Resulting reconstructed spatial resolution (FWHM) was determined from hot sphere inserts of a NEMA IEC phantom. Data with approx. 5-mm FWHM were retrospectively smoothed to achieve 7-mm FWHM. List mode data were rebinned for acquisition times of 120/90/60 s. Threshold-based delineation of primary tumor MTV was followed by evaluation of relative ASP/SUVmax/MTV differences between datasets and resulting proportions of discordantly classified cases.

Results

Reconstructed resolution for narrow/medium/wide in-plane filter (or low/medium/high beta) was approx. 5/7/9 mm FWHM. Comparing different pairs of reconstructed resolution between TOF4/8, PSF + TOF2/17, Q.Clear and the reference algorithm TOF4/16, ASP differences was lowest at FWHM of 7 versus 7 mm. Proportions of discordant cases (ASP > 19.5% vs. ≤ 19.5%) were also lowest at 7 mm (TOF4/8, 2%; PSF + TOF2/17, 4%; Q.Clear, 10%). Smoothing of 5-mm data to 7-mm FWHM significantly reduced discordant cases (TOF4/8, 38% reduced to 2%; PSF + TOF2/17, 12% to 4%; Q.Clear, 10% to 6%), resulting in proportions comparable to original 7-mm data. Shorter acquisition time only increased proportions of discordant cases at < 90 s.

Conclusions

ASP differences were mainly determined by reconstructed spatial resolution, and multicenter studies should aim at comparable FWHM (e.g., 7 mm; determined by in-plane filter width). This reduces discordant cases (high vs. low ASP) to an acceptable proportion for TOF and PSF + TOF of < 5% (Q.Clear: 10%). Data with better resolution (i.e., lower FWHM) could be retrospectively smoothed to the desired FWHM, resulting in a comparable number of discordant cases.

This work deals with the \Full-Core" VVER-1000 calculation benchmark which was proposed on the 26th Symposium of AER [1]. Recently, the calculation benchmarks \Full-Core" VVER-440 [2] and its extension [3] have been introduced in the AER community with positive response [4, 5]. Therefore we have decided to prepare a similar benchmark for VVER-1000. This benchmark is also a 2D calculation benchmark based on the VVER-1000 reactor core cold state geometry, explicitly taking into account the geometry of the radial reflector. The loading pattern for this core is very similar to the fresh fuel loading of cycle 9 at Unit 1 of the Temelin NPP (Czech Republic). This core is filled with six types of fuel assemblies with enrichment from 1.3%w 235U to 4.0%w 235U with up to 9 fuel pins with Gd burnable absorber per FA. The main task of this benchmark is to test the pin-by-pin power distribution in fuel assemblies predicted by macro-codes that are used for neutron-physics calculations especially for VVER reactors. In this contribution we present the overview of available macro-codes results.

Novel Ni-Co-Mn-Ti all- d -metal Heusler alloys are exciting due to large multicaloric effects combined with enhanced mechanical properties. An optimized heat treatment for a series of these compounds leads to very sharp phase transitions in bulk alloys with isothermal entropy changes of up to 38 J kg⁻¹ K⁻¹ for a magnetic field change of 2 T. The differences of as-cast and annealed samples are analyzed by investigating microstructure and phase transitions in detail by optical microscopy. We identify different grain structures as well as stoichiometric (in)homogenieties as reasons for differently sharp martensitic transitions after ideal and non-ideal annealing. We develop alloy design rules for tuning the magnetostructural phase transition and evaluate specifically the sensitivity of the transition temperature towards the externally applied magnetic fields (dT_t/μ₀dH) by analyzing the different stoichiometries. We then set up a phase diagram including martensitic transition temperatures and austenite Curie temperatures depending on the e/a ratio for varying Co and Ti content. The evolution of the Curie temperature with changing stoi- chiometry is compared to other Heusler systems. Density Functional Theory calculations reveal a correlation of T_C with the stoichiometry as well as with the order state of the austenite. This combined approach of experiment and theory allows for an efficient development of new systems towards promising magnetocaloric properties. Direct adiabatic temperature change measurements show here the largest value of -4 K in a magnetic field change of 1.93 T for Ni₃₅Co₁₅Mn₃₇Ti₁₃.

The flux-weighted average cross-sections of ^natDy(γ, xn)^159,157,155Dy reactions were measured at the bremsstrahlung end-point energies of 12, 14, 16, 65 and 75 MeV with the activation and off-line γ-ray spectrometric technique using the 20 MeV Electron Linac for beams with high Brilliance and low Emittance (ELBE) at Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany and the 100 MeV electron linac at the Pohang Accelerator Laboratory, Korea. The ^natDy(γ, xn)^157,155Dy reaction cross sections as a function of photon energy were also calculated theoretically using TALYS 1.9 code. Then the flux-weighted average values at different end-point energies were obtained based on the theoretical values of mono-energetic photons. These values were compared with the flux-weighted values of present work and are found to be in general agreement. It was also found that the experimental and theoretical formation cross sections of ¹⁵⁹Dy, ¹⁵⁷Dy and ¹⁵⁵Dy from the ^natDy(γ, xn) reactions increased from their respective threshold values to a certain energy where other reaction channels opened. After reaching a maximum value, the individual reaction cross-sections slowly decreased with the increase of the bremsstrahlung energy due to the initiation of other competing reactions at higher energy, which indicates the impact of the excitation energy. However, the production cross sections of ¹⁵⁷Dy and ¹⁵⁵Dy from the ^natDy(γ, xn) reactions slightly increase in between and then decreased slowly with bremsstrahlung energy, which is due to the contributing reactions of higher mass isotopes.

The screening of a test charge by partially degenerate non-ideal free electrons at conditions related to warm dense matter and dense plasmas is investigated using linear response theory and the local field correction based on ab inito Quantum Monte-Carlo simulations data. The analysis of the obtained results is performed by comparing to the random phase approximation and the Singwi-Tosi-Land-Sjölander approximation. The applicability of the long-wavelength approximation for the description of screening is investigated. The impact of electronic exchange-correlations effects on structural properties and the applicability of the screened potential from linear response theory for the simulation of the dynamics of ions are discussed.

There is growing interest in warm dense matter (WDM), an exotic state on the border between condensed matter and plasmas. Due to the simultaneous importance of quantum and correlation effects, WDM is complicated to treat theoretically. A key role has been played by ab initio path integral Monte Carlo (PIMC) simulations, and recently extensive results for thermodynamic quantities have been obtained. The first extension of PIMC simulations to the dynamic structure factor of the uniform electron gas was reported by Dornheim et al. [Phys. Rev. Lett. 121, 255001 (2018)]. This was based on an accurate reconstruction of the dynamic local field correction. Here we extend this concept to other dynamical quantities of the warm dense electron gas including the dynamic susceptibility, the dielectric function, and the conductivity.

Wire-mesh sensor (WMS) is an instrument used to visualize and estimate derived parameters of multiphase flows, i.e. gas void fraction and liquid hold-up. Due to its high temporal and spatial resolution, the sensor has been widely applied in the investigation of fluid dynamics. However, the structure of WMS is composed of intrusive electrodes and its image resolution is associated to the number of crossing points formed by the transmitter and receiver wires. In many processes, however, the intrusiveness caused by the electrodes may be a limitation on its use, since they increase the pressure drop and might fragment bubbles depending on the flow condition. Therefore, the reduction of the number of electrodes could probably extend the application field of wire-mesh sensors. Thus, we propose an image reconstruction method to increase resolution of WMS data with fewer wires than most WMS reported in the literature. Hence a reduction of intrusive effects on the process may be achieved. The proposed reconstruction method is based on the Minimum Mean Squared Error (MMSE) estimator. Experimental flow data from a 16x16 WMS are used to produce a Multivariate Gaussian flow model, which in turn is used as regularization in the reconstruction. A sensitive matrix is estimated by finite element method (FEM). Experimental data from two-phase water-gas at slug flow condition are used to validate the proposed method and compared with cubic interpolation. The results show that the MMSE estimator performs better than cubic interpolation and the standard direct problem formulation, reducing the void fraction deviation from 18.20% to 7.92% in the worst case (2x2 WMS).

We investigate the energy-loss characteristics of an ion in warm dense matter (WDM) and dense plasmas concentrating on the influence of electronic correlations. The basis for our analysis is a recently developed ab initio quantum Monte Carlo– (QMC) based machine learning representation of the static local field correction (LFC) [Dornheim et al., J. Chem. Phys. 151, 194104 (2019)], which provides an accurate description of the dynamical density response function of the electron gas at the considered parameters. We focus on the polarization-induced stopping power due to free electrons, the friction function, and the straggling rate. In addition, we compute the friction coefficient which constitutes a key quantity for the adequate Langevin dynamics simulation of ions. Considering typical experimental WDM parameters with partially degenerate electrons, we find that the friction coefficient is of the order of γ/ωpi=0.01, where ωpi is the ionic plasma frequency. This analysis is performed by comparing QMC-based data to results from the random-phase approximation (RPA), the Mermin dielectric function, and the Singwi-Tosi-Land-Sjölander (STLS) approximation. It is revealed that the widely used relaxation time approximation (Mermin dielectric function) has severe limitations regarding the description of the energy loss of ions in a correlated partially degenerate electrons gas. Moreover, by comparing QMC-based data with the results obtained using STLS, we find that the ion energy-loss properties are not sensitive to the inaccuracy of the static local field correction (LFC) at large wave numbers, k/kF>2 (with kF being the Fermi wave number), but that a correct description of the static LFC at k/kF≲1.5 is important.

We present extensive ab initio path-integral Monte Carlo (PIMC) simulations of two-dimensional quantum dipole few-body systems (2≤N≤7) in a harmonic confinement, taking into account both Bose- and Fermi-statistics. This allows us to study the nonclassical rotational inertia, which can lead to a negative superfluid fraction in the case of fermions [Phys. Rev. Lett. 112, 235301 (2014)]. Moreover, we study in detail the structural characteristics of such systems and are able to clearly resolve the impact of quantum statistics on density profiles and the respective shell structure. Further, we present results for a more advanced center-two-particle correlation function [Phys. Rev. E 91, 043104 (2015)], which allows detection of differences between Fermi and Bose systems even when they are almost absent in other observables like the density. Overall, we find that bosonic systems sensitively react to even small values of the dipole-dipole coupling strength, whereas such a weak interaction is effectively masked for fermions by the Pauli exclusion principle. In addition, the abnormal superfluid fraction for fermions is not reflected by the structural properties of the system, which are equal to the bosonic case even though the moments of inertia diverge from each other. Lastly, we have explored the possibility of fermionic PIMC simulations of quantum dipole systems despite the notorious fermion sign problem, which can be further extended in future investigations in this field.

Quantum Monte Carlo (QMC) belongs to the most accurate simulation techniques for quantum many-particle systems. However, for fermions, these simulations are hampered by the sign problem that prohibits simulations in the regime of strong degeneracy. The situation changed with the development of configuration path integral Monte Carlo (CPIMC) by Schoof et al. [Contrib. Plasma Phys. 51, 687 (2011)] that allowed for the first ab initio simulations for dense quantum plasmas [Schoof et al., Phys. Rev. Lett. 115, 130402 (2015)]. CPIMC also has a sign problem that occurs when the density is lowered, i.e., in a parameter range that is complementary to traditional QMC formulated in coordinate space. Thus, CPIMC simulations for the warm dense electron gas are limited to small values of the Brueckner parameter—the ratio of the interparticle distance to the Bohr radius—rs=r⎯⎯⎯/aB≲1
. In order to reach the regime of stronger coupling (lower density) with CPIMC, here we investigate additional restrictions on the Monte Carlo procedure. In particular, we introduce two different versions of “restricted CPIMC”—called RCPIMC and RCPIMC+—where certain sign changing Monte Carlo updates are being omitted. Interestingly, one of the methods (RCPIMC) has no sign problem at all, but it introduces a systematic error and is less accurate than RCPIMC+, which neglects only a smaller class of the Monte Carlo steps. Here, we report extensive simulations for the ferromagnetic uniform electron gas with which we investigate the properties and accuracy of RCPIMC and RCPIMC+. Furthermore, we establish the parameter range in the density–temperature plane where these simulations are both feasible and accurate. The conclusion is that RCPIMC and RCPIMC+ work best at temperatures in the range of Θ = kBT/EF ∼ 0.1…0.5, where EF is the Fermi energy, allowing to reach density parameters up to rs ∼ 3…5, thereby partially filling a gap left open by existing ab initio QMC methods.

The reconstruction of austenite grain boundaries in bainitic reactor pressure vessel (RPV) steels by means of electron backscatter diffraction (EBSD) was done on two examples. In the case of VVER-440 RPV steel the reconstruction works very well, while in JFL RPV steel the reconstruction is faulty due to the accented presence of low angle boundaries.

Combined experimental and modeling studies of the magnetocaloric effect, ultrasound, and magnetostriction were performed on single-crystal samples of the spin-dimer system Sr₃Cr₂O₈ in large magnetic fields to probe the spin-correlated regime in the proximity of the field-induced XY-type antiferromagnetic order also referred to as a Bose-Einstein condensate of magnons. The magnetocaloric effect, measured under adiabatic conditions, reveals details of the field-temperature (H, T ) phase diagram, a dome characterized by critical magnetic-fields H_c1 = 30.4, H_c2 = 62 T, and a single maximum ordering temperature T_max(45 T) = 8 K. The sample temperature was observed to drop significantly as the magnetic field is increased, even for initial temperatures above Tmax, indicating a significantmagnetic entropy associated with the field-induced closure of the spin gap. The ultrasound and magnetostriction experiments probe the coupling between the lattice degrees of freedom and the magnetism in Sr₃Cr₂O. Our experimental results are qualitatively reproduced by a minimalistic phenomenological model of the exchange striction by which sound waves renormalize the effective exchange couplings.

In this study, we report on the observation of de Haas–van Alphen–type quantum oscillations (QOs) in the ultrasound velocity of NbP as well as “giant QOs” in the ultrasound attenuation in pulsed magnetic fields. The difference in the QO amplitude for different acoustic modes reveals a strong anisotropy of the effective deformation potential, which we estimate to be as high as 9 eV for certain parts of the Fermi surface. Furthermore, the natural filtering of QO frequencies and the tracing of the individual Landau levels to the quantum limit allows for a more detailed investigation of the Fermi surface of NbP, as was previously achieved by means of analyzing QOs observed in magnetization or electrical resistivity.

Manufactured nanomaterials (NMs) are materials in which 50% or more of the particles have one or more dimensions between 1 nm and 100 nm. These NMs show interesting properties. However, the same properties that motivate their use in applications are also reason for concern, as NMs can cause toxic reactions and have mobilities in the environment different from bulk materials of the same elements. Despite considerable scientific efforts, the selective detection of manufactured NMs in environmental compartments is still a very complex and challenging task. An expert review of the literature has been conducted to identify relevant methods for nanomaterial detection in complex media in the context of environmental monitoring and a need for action was concluded from the existing body of work.
A literature review was performed using predominantly “Web of Science”. More than 150 scientific publications which themselves refer to more than 10000 sources were evaluated concerning nanoparticle detection methods. The techniques identified through the literature review were evaluated for their capability to detect the relevant NM-related properties such as size, concentration, com- position, shape, etc. of arbitrary NMs in environmental samples.
Evaluating the relevant literature quickly led to the conclusion that while some detection methods will lend themselves more easily towards detection of NMs in a specific environmental compartment, there is no strictly compartment specific method. NMs can be detected with any of the different methods after application of suitable sample preparation techniques. Consequently, a generalized method for NM detection in environmental samples would consist of standardized sampling procedures followed by an extraction step that serves to largely remove the complex matrix followed by a size fractionation step which would then lead into a multi-method analysis depending on the desired information depth.
The need for action for the establishment of routine environmental monitoring of manufactured NMs is thus the development, validation and coupling of suitable extraction, pre-sorting and if necessary pre- concentration procedures, as well, as analysis techniques. One promising combined approach would consist of: CPE, AF4, MALS and sp-ICP-TOF-MS.

Waste water treatment plants (WWTPs) represent an important step in the life cycle of manufactured nanomaterials. A considerable amount of nanoparticles (NPs) that are released from consumer products will end up in WWTPs, so that WWTPs can both serve as a potential end of life point for these nanoparticles, as well as a point of reentry into the environment via the WWTP effluents. It is thus of utmost importance to accurately quantify the fate of manufactured nanomaterials in waste water treatment in order to assess the risk
We used the radiolabeling of nanoparticles to accurately quantify the distribution of nanoparticles between the effluents of a model waste water treatment plant. In order to achieve this TiO2 NP were radiolabeled with V-48 using proton irradiation at our cyclotron. Multi-wall carbon nanotubes (MWCNT) were radiolabeled with Be-7 via recoil at our cyclotron. CdSe/ZnS Quantum dots were radiolabeled with Zn-65 and Se-75 via radiosynthesis. The radiolabeled NPs were used in batch experiments and model waste water treatment plant experiments.
The radiolabeling allowed us to quantify NP distribution between sludge and water phase in the WWTP and in the WWTP effluents. A distribution of about 10000 : 1 between sludge-associated NPs and free NPs in water is reached in the WWTP already shortly after injection of the NPs. Thus the elimination of the NPs from the WWTP is mainly controlled by the removal of surplus sludge taking place every day of operation. The NPs are eliminated from the WWTP with a half-life of about 6 days reflecting the pre-set sludge age. After about 22 days of operation 10 % of the initial NPs remain in the WWTP. Approximately 1 % of the NPs leave the WWTP via the cleared waste water, mainly associated with non-sedimented sludge particles, such that only about 1 ‰ of the NPs leave the WWTP as free particles via the cleared water. An impact of the NPs on the clearing process, as monitored by chemical oxygen demand of the inflow vs. the outflow, was not observed.

Accurate quantification of nanoparticles (NPs) in complex media remains a considerable challenge when assessing the risk that manufactured nanoparticles pose for humans and environment. The radiolabeling of nanoparticles is a valuable tool for conducting lab-studies with realistic systems and realistically low NP concentrations.
We have developed various methods of introducing radiotracers into some of the most common nanoparticles, such as Ag, carbon, SiO2, CeO2 and TiO2 nanoparticles. The labeling techniques are the synthesis of the nanoparticles using radioactive starting materials, the binding of the radiotracer to the nanoparticles, the activation of the nanoparticles using proton irradiation, the recoil labeling utilizing the recoil of a nuclear reaction to implant a radiotracer into the nanoparticle, and the in-diffusion of radiotracers into the nanoparticles at elevated temperatures. Using these methods we have produced [105/110mAg]Ag, [124/125/131I]CNTs, [48V]TiO2, [13/1419Ce]CeO2, [7Be]MWCNT, [64Cu]SiO2, [44/45Ti]TiO2, etc. for accurate quantification in complex media at environmentally relevant low concentrations.
The nanoparticles labeled by our methods can be detected at minimal concentrations well in the ng/L range even with a background of the same element and without complicated sample preparations necessary. The methods are adaptable for a wide range of other nanoparticles. The labeled particles have been successfully used in release studies, environmental mobility studies, fate studies in waste water treatment and plant uptake studies.

Bacterial attachment is crucial in many biotechnological applications, but many important bacterial strains cannot form biofilms. Biofilms can damage materials, and current strategies to manage biofilms are focused on inhibition and removal of biofilm. Biofilm formation is inevitable when materials are exposed to microbes and instead of biofilm prevention, we propose management of microbial composition by formation of biofilms with beneficial microbes. Since bacteria need to overcome a high repulsive force to attach to the surface and later to grow and multiply on it, electrostatic modification of the surfaces of cells or the material by polyelectrolytes (PE) was used in our approach, enabling efficient attachment of viable bacterial cells. Since highly positively charged PEs are known to be bactericidal, they were acetylated to reduce their toxicity, while preserving their net positive charge and ensuring cell viability. In our study bacterial strains were selected according to their intrinsic capability of biofilm formation, their shape variety and cell wall structure. These strains were tested to compare how the artificially prepared vs. natural biofilms can be used to populate the surface with beneficial bacteria. Using an artificial biofilm constructed of the potentially probiotic isolate Bacillus sp. strain 25.2. M, reduced the attachment and induced complete inhibition of E. coli growth over the biofilm. This study also revealed that the modification of the surfaces of cells or material by polyelectrolytes allows the deposition of bacterial cells, biofilm formation and attachment of biofilm non-forming cells onto surfaces. In this way, artificial biofilms with extended stability can be constructed, leading to selective pressure on further colonization of environmental bacteria.

The proposed research paper has a strong application bias and aims to address the practical problem of managing dozens, potentially hundreds of OpenFOAM cases. The workflow management includes routine tasks such as migrations on new solver versions, testing sub-models and solvers, as well as developing entirely new OpenFOAM applications validated against established setups. The proposed methodology was successfully tested on a set of 55 OpenFOAM cases specifically designed for the validation of new sub-models for Euler-Euler simulations of multiphase flows.

Two-dimensional (2D) materials have many unique properties, which can be exploited in various applications. In particular, electronic devices based on 2D materials should ideally be suited for the operation in outer cosmic space due to their low weight, small size and low power consump- tion. This brings about the issue of their radiation hardness, or tolerance, which has recently been addressed in a number of studies. The results of these investigations are somewhat counterintu- itive: although one can naively expect that atomically thin structures should easily be destroyed by the beams of energetic particles, the devices made from 2D materials were reported to exhibit extraordinary radiation hardness. In this Focus article, an overview of the recent studies on the subject is given, followed by the discussion of the origin of the reported high tolerance, which is inherently related to the response of 2D materials, the systems with the reduced dimensionality, to irradiation. The analysis of the experimental and theoretical data on the behavior of 2D systems under irradiation indicates that although free-standing 2D materials can indeed be referred to as radiation resilient systems under irradiation conditions corresponding to the outer space, this is generally not the case, as the environment, e.g., the substrate, can strongly influence the radiation tolerance of 2D materials and devices based on these systems.

Chemical zoning of crystals is often found in nature. Crystal zoning can play a role in a mineral's thermodynamic stability and in its kinetic response in the presence of fluids. Dissolution experiments at far-from-equilibrium conditions were performed using a sandstone sample containing calcite cement crystal patches. The surface normal retreat of the calcite crystals was obtained by vertical scanning interferometry (VSI) in their natural position in the rock. Dissolution rate maps showed contrasting surface dissolution areas within the crystals, in the same locations where electron microprobe (EMP) maps showed the presence of manganese (Mn) and iron (Fe) substitutions for calcium in the calcite structure. Iron zoning was only identified in combination with manganese. Maximum registered manganese contents were 1.9(9) wt% and iron were 2(1) wt%. Manganese zoning of only 0.9(5) wt% resulted in around 40% lower dissolution rates than the adjacent pure calcite zones. The combination of both Mn and Fe cation substitutions resulted in one order of magnitude lower dissolution rates compared to pure calcite in the same sample. These results show that mineral zoning can significantly affect reaction rates, a parameter that needs better understanding for the improvement of kinetic geochemical models at the pore scale.

The feedback between dyke and sill intrusions and the evolution of stresses within volcanic systems is poorly understood, despite its importance for magma transport and volcano instability. Long-lived ocean island volcanoes are crosscut by thousands of dykes, which must be accommodated through a combination of flank slip and visco-elastic deformation. Flank slip is dominant in some volcanoes (e.g., Kilauea), but how intrusions are accommodated in other volcanic systems remains unknown. Here we apply digital mapping techniques to collect > 400,000 orientation and aperture measurements from 519 sheet intrusions within Volcán Taburiente (La Palma, Canary Islands, Spain) and investigate their emplacement and accommodation. We show that vertically ascending dykes were deflected to propagate laterally as they approached the surface of the volcano, forming a radial dyke swarm, and propose a visco-elastic model for their accommodation. Our model reproduces the measured dyke-aperture distribution and predicts that stress accumulates within densely intruded regions of the volcano, blocking subsequent dykes and causing eruptive activity to migrate. These results have significant implications for the organisation of magma transport within volcanic edifices, and the evolution and stability of long-lived volcanic systems.

This book constitutes the refereed post-conference proceedings of 10 workshops held at the 35th International ISC High Performance 2020 Conference, in Frankfurt, Germany, in June 2020:

First Workshop on Compiler-assisted Correctness Checking and Performance Optimization for HPC (C3PO); First International Workshop on the Application of Machine Learning Techniques to Computational Fluid Dynamics Simulations and Analysis (CFDML); HPC I/O in the Data Center Workshop (HPC-IODC); First Workshop \Machine Learning on HPC Systems" (MLHPCS); First International Workshop on Monitoring and Data Analytics (MODA); 15th Workshop on Virtualization in High-Performance Cloud Computing (VHPC).

The 25 full papers included in this volume were carefully reviewed and selected. They cover all aspects of research, development, and application of large-scale, high performance experimental and commercial systems. Topics include high-performance computing (HPC), computer architecture and hardware, programming models, system software, performance analysis and modeling, compiler analysis and optimization techniques, software sustainability, scientific applications, deep learning.

In the last decade, several national and European funding programs addressed the resource potential of mine wastes (including tailings and metallurgical slag dumps), with a clear focus on the development of new sources for critical raw materials (CRM). The European Commission defined CRMs as highly important for the European high tech industry. European and national resource strategies refer to this definition and include the development of new CRM sources as one of their main objectives. The German Federal Ministry for Research and Education (BMBF) funded the program “r3 –strategic metals and minerals – innovative technologies for resource efficiency” that started in 2012. The aim of the program was to ensure the domestic supply of strategically significant metals and minerals. Suitable projects had to act in the fields of recycling and substitution of raw materials as well as in the field of reduced material consumption. Urban mining and the evaluation of resource efficiency were further topics that suited the program. The Helmholtz Institute Freiberg for Resource Technology (HIF) and the Fraunhofer Institute for Environmental, Safety, and Energy Technology (UMSICHT) worked already together in different projects about mine waste characterization and resource extraction in r3.
The Helmholtz Institute Freiberg for Resource Technology pursues the objective of developing innovative technologies for the economy so that mineral and metalliferous raw materials become more available, undergo highly efficient processes and recycle in an environmentally
friendly manner. As a part of the national strategy for raw materials in 2011, the German government initiated the HIF. It is a constituent part of the Helmholtz-Zentrum Dresden-Rossendorf and works in close collaboration with TU Bergakademie Freiberg. The HIF is a core member of the European EIT RawMaterials network, having played a decisive role in its establishment. Fraunhofer UMSICHT is a pioneer for sustainable energy and raw materials management by supplying and transferring scientific results into companies, society and politics. The dedicated UMSICHT team researches and develops, together with partners, sustainable products, processes and services. Together with industry and public partners, such as the Geological Survey of Germany (BGR), UMSICHT and HIF founded the r³-mine-waste-cluster in order to determine a realistic mine waste
potential for Germany and give a reliable resource estimation for secondary raw materials. Nowadays, however, there is a political and public interest beyond the potential of valuable metals from mine wastes. After the catastrophic tailings accident in Vales Corrego do Feijão mine, Brazil, the social pressure to lower these risks raised on the mining industry, on the mine waste owners (e.g. states) and on the politics. With the new Global Industry Standard on Tailings Management a new set of guidelines was developed in order to avoid these accidents in the future. “The International Council
on Mining and Metals (ICMM), the United Nations Environment Programme (UNEP) and the Principles for Responsible Investment (PRI) share a commitment to the adoption of global best practices on tailings storage facilities. They have co-convened this global tailings review to establish an international standard.” Their environmental risks and at the same time their high potential as a source for (critical) raw materials make mine waste projects a complex exercise. There is a need for solutions that respect environmental, technical, civil and economic issues and provide holistic and sustainable approaches. In order to validating and adjusting different approaches, the HIF coordinates the recomine-alliance. Local stakeholders representing environmental, technical, scientific, governmental and civil institutions assemble in recomine for a development of holistic mine waste solutions for a worldwide application.

We study numerically localised short-circuits in Li||Bi liquid metal batteries. In the prototype of a classical, three liquid-layer system, we assume a perceptible local deformation of the Li-salt interface. We find that there exists always a critical current at which a Li-droplet is cut off from this hump, and transferred to the Bi-phase. In a second case, we assume that the molten Li is contained in a metal foam, and that a small Li-droplet emerges below this foam due to insufficient wetting. This droplet is deformed by Lorentz forces, until eventually being pinched off. Here, the critical current is slightly lower than in the three layer system, and both, a droplet transfer and complete short-circuits are observed. Finally, we discuss the relevance of our simulations for experimentally observed short-circuits and non-faradaic Li-transfer.

Artificial spin ices are periodic arrangements of interacting nanomagnets that have been successfully used to investigate emergent phenomena in the presence of geometric frustration. Recently, it has become clear that artificial spin ices equally have the potential to be used as building blocks for creating functional materials, such as magnonic crystals and ratchets, in addition to supporting a large number of programmable magnetic states. In this context, we investigate the magnetization dynamics in a system exhibiting asymmetric magnetostatic interactions owing to locally broken structural symmetry. We find that this gives rise to a rich spectrum that can be tuned through an external field. We also determine the evolution of the observed excitation modes, starting with building blocks and evolving into larger arrays, highlighting the role of symmetry breaking in defining the mode spectrum of the system. Concurrently, the increasing complexity of the spectrum leads to the existence of a large number of modes over a narrow range of frequencies. These results contribute to the understanding of magnetization dynamics in spin ice systems beyond the kagome and square ice geometries with a view towards the realization of reconfigurable magnonic crystals based on spin ices.

Detection of patients with esophageal squamous cell carcinoma (ESCC) who do not benefit from standard chemoradiation (CRT) is an important medical need. Radiomics using 18-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a promising approach. In this retrospective study of 184 patients with locally advanced ESCC. 152 patients from one center were grouped into a training cohort (n = 100) and an internal validation cohort (n = 52). External validation was performed with 32 patients treated at a second center. Primary endpoint was disease-free survival (DFS), secondary endpoints were overall survival (OS) and local control (LC). FDG-PET radiomics features were selected by Lasso-Cox regression analyses and a separate radiomics signature was calculated for each endpoint. In the training cohort radiomics signatures containing up to four PET derived features were able to identify non-responders in regard of all endpoints (DFS p < 0.001, LC p = 0.003, OS p = 0.001). After successful internal validation of the cutoff values generated by the training cohort for DFS (p = 0.025) and OS (p = 0.002), external validation using these cutoffs was successful for DFS (p = 0.002) but not for the other investigated endpoints. These results suggest that pre-treatment FDG-PET features may be useful to detect patients who do not respond to CRT and could benefit from alternative treatment.

Nowadays, due to the internal combustion engine industry's orientation towards downsizing, modern efficient cooling systems with lower power consumption, small size and high compactness are essential. To improve these items, applying precision cooling and boiling phenomenon are inevitable. Having an appropriate coolant flow velocity which leads to utilize only the advantages of boiling heat transfer has always been a challenge. Two experimental test rigs, one for modeling and accurate prediction of subcooled flow boiling and the other for measurement and validation of coolant velocity in a water jacket by particle image velocimetry method are set up. An accurate and robust empirical correlation for modeling of subcooled flow boiling which occurs in the water jacket is developed. Then, through a three dimensional thermal analysis, the heat transfer parameters such as heat flux and temperature distribution of the internal combustion engine cylinder block and head are obtained numerically. Finally, as the main achievement of this study, a diagram is presented which combines the concept of precision cooling and subcooled flow boiling and gives the minimum coolant velocity in terms of heat flux. Without going into detail thermo-fluids analysis, this provides a convenient tool to determine the minimum velocity of the coolant flow over the different regions of the internal combustion engine water jacket wall to keep it at its allowable temperature range.

The n-type doping of Ge is a self-limiting process due to the formation of vacancy-donor complexes (DnV with n ≤ 4) that deactivate the donors. This work unambiguously demonstrates that the dissolution of the dominating P4V clusters in heavily phosphorus-doped Ge epilayers can be achieved by millisecond-flash lamp annealing at about 1050 K. The P4V cluster dissolution increases the carrier concentration by more than three-fold together with a suppression of phosphorus diffusion. Electrochemical capacitance-voltage measurements in conjunction with secondary ion mass spectrometry, positron annihilation lifetime spectroscopy and theoretical calculations enabled us to address and understand a fundamental problem that has hindered so far the full integration of Ge with complementary-metal-oxide-semiconductor technology.

An optimized equipment design for natural gas processing and liquefaction plants becomes increasingly difficult with changing process conditions: Particularly low values of surface tension create rising challenges on the design of phase separators and column internals. The TERESA test rig at HZDR was designed to allow the investigation of multi-phase thermohydraulics and phase separator performance under critical fluid properties in industrial dimensions. A versatile pipe test section is available in DN200 and equipment internals may be tested in a sectional DN300/DN500 test separator. The applied test fluid shows a high vapor-liquid density difference between 1470 and 940 kg/m³, viscosity as low as 0.12 mm²/s, and surface tension down to 1.3 mN/m. Volumetric liquid and vapor flow rates may be varied up to 9 and 530 m³/h in the test rig, respectively.

Background: Studies indicate that all left-sided breast cancer patients benefit from the deep inspiration breath hold technique (DIBH), however, not all patients experience the same benefit. A meta-analysis performed by Latty et al. reviewed 18 studies evaluating DIBH, which demonstrated a relative reduction of mean dose (Dmean) to the heart ranging from 26.2% to 75% as compared to irradiation in free breathing. However, as most papers report averages rather than patient-by-patient analyses, outliers remain unidentified. Thus, a lack of data and knowledge exists in determining selection criteria to predict individual patient benefit from DIBH.

Methods: We are planning to establish a large retrospective database of breast cancer patients treated with deep inspiration breath hold (DIBH) radiotherapy techniques. Data will be collected anonymized from all participating centres. A detailed analysis of:

1. Differences in OAR sparing by anatomical conditions
2. Differences in OAR sparing by used DIBH techniques (free breathing, RPM, surface scanning with camera or laser systems etc)
3. Differences in OAR sparing by fractionation schedules (normalized to EQD2)
4. Differences in OAR sparing by PTV volumes and CTV definitions

but not limited to, will be performed.

Discussion: Patient data will be stratified according to different anatomical conditions (such as large breasts vs. small breasts), radiation techniques, fractionation schedules and PTV volumes (for e.g. chest wall after mastectomy vs. breast only vs. breast and lymphatics etc). This multicentre database will allow for the first time an in depth analysis of the impact of DIBH. It will enhance our knowledge on outliers and will provide selection criteria to predict individual patient benefit from DIBH.

Micro- or nano-structured ferromagnetic layers often possess superior electrocatalytic properties but are difficult to manufacture in general. The present work investigates how a magnetic field can possibly support local cone growth on a planar electrode during electrodeposition, thus simplifying fabrication. Analytical and numerical studies were performed on conical structures of mm size to elaborate the influence of the magnetic forces caused by an electrode-normal external field. It is shown that, beside the Lorentz force studied earlier in the case of single cones [1], the magnetic gradient force enabled by the field alteration near the ferromagnetic cathode significantly supports cone growth. Detailed studies performed for sharp and flat single cones allow conclusions to be drawn on the support at different stages in the evolution of conical deformations. Furthermore, the influence from neighboring cones is studied with arrays of cones at varying distances apart. Nearby neighbors generally tend to mitigate the flow driven by the magnetic forces. Here, the support for cone growth originating from the magnetic gradient force is less heavily affected than that from the Lorentz force. Our results clearly show that the magnetic field has a beneficial effect on the growth of ferromagnetic conical structures, which could also be useful on the micro- and nanometer scales.

Wire mesh flooding point measurements at low surface tension < 10 mN m-1 were conducted using a refrigerant as model fluid. A new method for the calculation of wire mesh capacity was developed based on experimental data from literature and data from this study. In comparison to the well-known and widely adapted K-value method given in the Gas Processors Suppliers Association (GPSA) Engineering Databook and various other sources, the new method yields 3-38 % reduced wire mesh cross-sections for fluid systems at pressures above 20 bar(g) while retaining an inherent safety margin.

Tailored conditioning and control of flashing feeds in industrial applications requires knowledge of the evolving flow morphology and phase fractions along the feed pipe. Design methods obtained from reference systems (e.g. water/air) are hardly applicable for commercial scales and critical fluid properties (e.g. high vapor densities, low surface tension). In this study, the flow morphology of flashing feeds in a novel refrigerant test rig at critical fluid properties was analyzed using wire-mesh sensors at two locations along the feed pipe and experimental data from the water/air system.

Vortrag der GSB vor dem AGBR

The design of industrial feed line sections and the selection of appropriate inlet devices requires knowledge about the two-phase flow morphology and phase fractions in order to reduce costly overdesign. Since experimental data for two-phase pipe flows at industrial scale are hardly available, current prediction methods are subject to high unertainities. In this study, horizontal two-phase flow morphologies for different industrial feed line sections were studied using wire-mesh sensors at multiple locations along the pipe. The obtained phase fraction data are compared with correlations.

Background and purpose
In consequence of a previous study, where no protecting proton Flash effect was found for zebrafish embryos, potential reasons and requirements for inducing a Flash effect should be investigated with the beam pulse structure and the partial oxygen pressure (pO2) as relevant parameters.
Materials and methods
The experiments were performed at the research electron accelerator ELBE, whose variable pulse structure enables dose delivery as electron Flash and quasi-continuously (reference). Zebrafish embryos were irradiated with ~26 Gy either continuously with a dose rate of ~6.7 Gy/min or in one 111 µs long pulse with a pulse dose rate of 109 Gy/s and a mean dose rate of 105 Gy/s, respectively. Using the OxyLite system to measure the pO2 a low- (pO2 ≤ 5 mmHg) and a high-pO2 group were defined on basis of the oxygen depletion kinetics in sealed embryo samples.
Results
A protective Flash effect was seen for most endpoints ranging from 4 % less reduction in embryo length to about 20 – 25 % less embryos with spinal curvature and pericardial edema, relative to reference irradiation. The reduction of pO2 below atmospheric levels (148 mmHg) resulted in higher protection, which was however more pronounced in the low-pO2 group.
Conclusion
The Flash experiment at ELBE showed that the zebrafish embryo model is appropriate for studying the radiobiological response of high dose rate irradiation. Pulse dose and pulse dose rate as important beam parameters were confirmed as well as the pivotal role of pO2 during irradiation.

Instabilities in beam and bunch parameters, such as bunch charge, beam energy, or changes in the phase or amplitude of the accelerating field in the RF cavities can be the source of noise in the various secondary sources driven by the electron beam. Bunch charge fluctuations lead to in-tensity instabilities in the superradiant THz sources. The primary electron beam driving the light sources has a maximum energy of 40 MeV and a maximum current of 1.6 mA. Depending on the mode of operation required, there are two available injectors in use at ELBE. The first is the thermionic injector, which is used for regular operating modes and supports repetition rates up to 13 MHz and bunch charges up to 100 pC. The second is the SRF photo-cathode injector, which is used for experiments that may require lower emittance or higher bunch charges of up to 1 nC. It has a maximum repetition rate of 13 MHz, which can be adjusted to lower rates if desired, also including different macro pulse modes of operation. In this contribution, we will present our work in the pulse-resolved intensity measurement that allows for the correction of intensity instabilities.

Tray and point efficiencies are the key parameters for characterizing the performance of a distillation tray.
The tray efficiencies are experimentally determined mostly by sampling the incoming and exiting streams of liquid and gas over the tray. Contrarily, the point efficiency determination is technically challenging and thus, it is derived mainly from correlations or small-scale experiments. Only few studies on the experimental determination of point efficiencies on large-scale distillation trays exist. However, the traditional physical systems pose several technical restrictions and safety concerns that often prevent their integration with the available air/water column mockups.
In this study, the stripping of isobutyl acetate from an aqueous solution using air is proposed as a physical system. It offers several advantages over the traditional ones (in terms of adaptability to different gas and liquid flow rates, safety and minimum revamping requirements), and is proved suitable for being readily integrated into existing cold fluid air/water mockups without any major modification.
The liquid concentration distribution on an 800 mm dia. distillation sieve tray was investigated by sampling the liquid at different deck locations for subsequent UV-spectroscopy. The concentration distribution was used to obtain the point efficiency values accounting for both axial and transverse liquid mixing on the tray. The concentration distributions, tray and point efficiency values obtained for different weir loads showed good agreement with the predictions given by the correlations and models used in the literature. The proposed approach can also account for the effect of weeping on the tray efficiency.
Potential future application of the proposed approach can address the investigation and design of novel tray concepts (e.g. with liquid flow conditioners), the development and validation of point and tray efficiency models as well as the validation of CFD simulations.

When considering the flow of currents through obstacles, one core expectation is that the total resis- tance of sequential single resistors is additive. While this rule is most commonly applied to electronic circuits, it also applies to other transport phenomena such as the flow of colloids or nanoparti- cles through channels containing multiple obstacles, as long as these obstacles are sufficiently far apart. Here we explore the breakdown of this additivity for fluids of repulsive colloids driven over two energetic barriers in a microchannel, using real-space microscopy experiments, particle-resolved simulations, and dynamical density functional theory. If the barrier separation is comparable to the particle correlation length, the resistance is highly non-additive, such that the resistance added by the second barrier can be significantly higher or lower than that of the first. Surprisingly, in some cases the second barrier can even add a negative resistance, such that two identical barriers are easier to cross than a single one. We explain this counterintuitive observation in terms of the structuring of particles trapped between the barriers.

Metal pad roll instability is a well known phenomenon that occurs in aluminium reduction cells [1] Since long, scientists and engineers have been searching for an experimental model that recreates the metal pad roll instability in a well controlled laboratory environment. [2] partly succeeded in this task by using GaInSn eutectic alloy in replacement of aluminium and a steel wire array, in replacement of the badly conducting cryolite layer. A rolling wave motion was observed but comparison to fluid based theoretical models remains difficult.
In this talk, we demonstrate that it is possible to observe metal pad roll instability in a centimeter scale cylindrical set-up at room temperature and using different liquid metal pairs as working fluids: gallium liquid metal over mercury (immiscible case) or gallium over GaInSn eutectic alloy (miscible case). Despite the small difference in electrical conductivity, the stability theory of [3] suggests that metal pad roll instability occurs for reasonable values of the imposed magnetic field and electrical current. We confirm this theoretical prediction with some very challenging direct numerical simulations of the multiphase magnetohydrodynamical flow in this set-up, done with our massively parallel solver SFEMaNS [4].

Spin waves have the potential to be used as a next-generation platform for data transfer and processing as they can reach wavelengths in the nanometer range and frequencies in the terahertz range. To realize a spin-wave device, it is essential to be able to manipulate the amplitude as well as the phase of spin waves. Several theoretical and recent experimental works have also shown that the spin-wave phase can be manipulated by the transmission through a domain wall (DW). Here, we study propagation of spin waves through a DW by means of micro-focused Brillouin light scattering microscopy (μBLS). The 2D spin-wave intensity maps reveal that spin-wave transmission through a Néel DW is influenced by a topologically enforced circular Bloch line in the DW center and that the propagation regime depends on the spin-wave frequency. In the first regime, two spin-wave beams propagating around the circular Bloch line are formed, whereas in the second regime, spin waves propagate in a single central beam through the circular Bloch line. Phase-resolved μBLS measurements reveal a phase shift upon transmission through the domain wall for both regimes. Micromagnetic modeling of the transmitted spin waves unveils a distortion of their phase fronts, which needs to be taken into account when interpreting the measurements and designing potential devices. Moreover, we show that, by means of micromagnetic simulations, an external magnetic field can be used to move the circular Bloch line within the DW and to manipulate spin-wave propagation.
The authors thank R. Schäfer and O. Fruchart for the discussions on the DW classification.
This research was supported by the CEITEC Nano+ project (No. CZ.02.1.01/0.0/0.0/16013/0001728) and Austrian Science Fund (FWF) project I1937. M. Staňo acknowledges support by the ESF under the project CZ.02.2.69/0.0/0.0/19_074/0016239. CzechNanoLab project LM2018110 funded by MEYS CR is gratefully acknowledged for the financial support of the measurement and sample fabrication at the CEITEC Nano Research Infrastructure.

Metastable face-centered-cubic Fe78Ni22 thin films are excellent candidates for focused ion beam direct writing of magnonic structures due to their favorable magnetic properties after ion-beam-induced transformation. The focused ion beam transforms the originally nonmagnetic fcc phase into the ferromagnetic bcc phase with additional control over the direction of uniaxial magnetic in-plane anisotropy and saturation magnetization. Local magnetic anisotropy direction control eliminates the need for external magnetic fields, paving the way towards complex magnonic circuits with waveguides pointing in different directions. In the present study, we show that the magnetocrystalline anisotropy in transformed areas is strong enough to stabilize the magnetization in the direction perpendicular to the long axis of narrow waveguides. Therefore, it is possible to propagate spin waves in these waveguides in the favorable Damon-Eshbach geometry without the presence of any external magnetic field. Phase-resolved microfocused Brillouin light scattering yields the dispersion relation of these waveguides in zero as well as in nonzero external magnetic fields.

We present an investigation of a low-energy-triggered bulk gallium arsenide (GaAs) photoconductive semiconductor switch (PCSS) that is characterized by powerful avalanche domains. The performance of the switch is investigated using a reversely biased p⁺-i-n⁺ structure with 0.625-mm thickness, and the 8.0-kV, 170-ps bulk PCSS that is triggered by a 905-nm laser at the energy of 5.7 nJ is achieved. In the low-energy-triggered mode, it is found experimentally that the reduction of required energy for switching operation is not always kept by the continuous increase of the bias field in the bulk PCSS due to Franz–Keldysh effect. We also analyze the triggering efficiency depending on the laser wavelength numerically, and results indicate that the earlier formation of the powerful avalanche domains is realized by the increased wavelength, which causes lower laser energy for switching operation. Moreover, the prestudy of high-power microwave (HPM) applications is also introduced utilizing bulk PCSS, and we constructed the basic units for ultrawide-band (UWB) pulse and HPM-driven pulse.

Quantum cascade lasers (QCL) have revolutionized the generation of mid-infrared light. Yet, the ultrafast carrier transport in mid-infrared QCLs have so far constituted a seemingly insurmountable obstacle for the formation of ultrashort light pulses. Here, we demonstrate that careful quantum design of the gain medium and control over the intermode beat synchronization enable transform-limited picosecond pulses from QCL frequency combs. Both an interferometric radio-frequency technique and second-order autocorrelation shed light on the pulse dynamics and confirm that mode-locked operation is achieved from threshold to rollover current. Furthermore, we show that both antiphase and in-phase synchronized states exist in QCLs. Being electrically pumped and compact, mode-locked QCLs pave the way towards monolithically integrated non-linear photonics in the molecular fingerprint region beyond 6 μm wavelength.

The interaction of high-intensity laser pulses with solid targets can be used as a highly charged, energetic heavy ion source. Normally, intrinsic contaminants on the target surface suppress the performance of heavy ion acceleration from a high-intensity laser–target interaction, resulting in preferential proton acceleration. Here, we demonstrate that CW laser heating of 5 µm titanium tape targets can remove contaminant hydrocarbons in order to expose a thin oxide layer on the metal surface, ideal for the generation of energetic oxygen beams. This is demonstrated by irradiating the heated targets with a PW class high-power laser at an intensity of 5 x 10^21 W/cm^2, showing enhanced acceleration of oxygen ions with a non-thermal-like distribution. Our new scheme using a CW laser-heated Ti tape target is promising for use as a moderate repetition energetic oxygen ion source for future applications.

Reactive bubbly flows are found in many chemical and biochemical process-es. They are characterized by complex hydrodynamics that govern global mass transfer and reaction rates. Effects, which have to be taken into account when modelling and simulating the reaction progress are enhanced bubble-bubble interaction and bubble-induced turbulence as well as swarm-induced macro-convection. This poses great challenges on both, experimental analysis and numerical simulation. Bubble swarms at higher gas fractions are opaque, which limits the use of optical flow measurement techniques. Moreover, simu-lations at industrial scale are only feasible with point-bubble-based Euler-Euler or Euler-Lagrange approaches. Such approaches require closure relations, which account for all relevant interfacial forces as well as bubble-induced tur-bulence and coalescence including swarm effects. This chapter describes the progress in the experimental analysis and CFD simulation of reactive bubbly flows achieved during the time of the DFG Priority Programme SPP 1740. Ex-perimental studies in bubble columns reported in this Chapter were carried out at TU Dresden and OVGU Magdeburg. CFD model development and simula-tion has been carried out at OVGU Magdeburg using the Euler-Euler and Euler-Lagrange method and at TU Kaiserslautern and Helmholtz-Zentrum Dresden-Rossendorf using the Euler-Euler approach. As reaction systems the chemi-sorption of CO2 in NaOH solution and the reaction of FeII(edta) with NO were studied.

The main focus of this project was the experimental investigation of hydrody-namics and mass transfer characteristics together with a chemical reaction in a bubble column at higher gas holdup. Experiments were performed for chemical absorption of CO2 in alkaline solution of different pH, at homogenous bubbly flow conditions and up to 17% gas holdup. Ultrafast electron beam X-ray to-mography (UFXCT) has been used to obtain local gas holdup data and bubble characteristics and a wire-mesh sensor was used to measure species concentra-tion fields in the liquid bulk. In addition, experiments with the reactive system FeII(edta)/NO were carried out and a new a fiber optical probe was employed for local measurement of product concentration in the bubble wake.

This thesis experimentally demonstrates four approaches of frequency control of magnetic autooscillations in spin Hall nano-oscillators (SHNOs).
The frequency can be changed in the GHZ-range by external magnetic fields as shown in this work. This approach uses large electromagnets, which is inconvenient for future applications.The nonlinear coupling between oscillator power and frequency can be used to control the latter one by changing the applied direct current to the SHNO. The frequency can be controlled over a range of several 100 MHz as demonstrated in this thesis.
The first part of the experimental chapter demonstrates the synchronization (injection-locking) between magnetic auto-oscillations and an external microwave excitation. The additionally applied microwave current generates a modulation of the effective magnetic field, which causes the interaction with the auto-oscillation. Both synchronize over a range of several 100 MHz. In this range, the auto-oscillation frequency can be controlled by the external stimulus. An increase of power and a decrease of line width is achieved in the synchronization range. This is explained by the increased coherence of the auto-oscillations. A second approach is the synchronization of auto-oscillations to an alternating magnetic field. This field is generated by a freestanding antenna, which is positioned above the SHNO.
The second part of the experimental chapter introduces a bipolar concept of SHNOs and its experimental demonstration. In contrast to conventional SHNOs, bipolar SHNOs generate autooscillations for both direct current polarities and both directions of the external magnetic field. This is achieved by combining two ferromagnetic layers in an SHNO. The combination of two different ferromagnetic materials is used to switch between two frequency ranges in dependence of the direct current polarity since it defines the layer showing auto-oscillations. This approach can be used to change the frequency in the GHz-range by switching the direct current polarity.

The spontaneous magnetic orders arising in ferro-, ferri- and antiferromagnets stem from various magnetic interactions. Depending on the interplay and competition among the Heisenberg exchange interaction, Dzyaloshinskii-Moriya exchange interaction, magnetic dipolar interaction and crystal anisotropies, a great variety of magnetic textures may be stabilized, such as magnetic domain walls, vortices, Skyrmions and spiral helical structures. While each of these spin textures responds to external forces in a specific manner with characteristic resonance frequencies, they also interact with magnons, the fundamental collective excitation of the magnetic order, which can propagate in magnetic materials free of charge transport and therefore with low energy dissipation. Recent theories and experiments found that the interplay between spin waves and magnetic textures is particularly interesting and rich in physics. In this review, we introduce and discuss the theoretical framework of magnons living on a magnetic texture background, as well as recent experimental progress in the manipulation of magnons via magnetic textures. The flexibility and reconfigurability of magnetic textures are discussed regarding the potential for applications in information processing schemes based on magnons.

Microrganisms can influence the performance of nuclear waste repositories through activities or processes that affect radionuclide migration. In the case of subterranean salt-based repositories, the influence of microorganisms may be limited by the unique constraints of such sutes (e.g. high ionic strength, low water activity, nutient supply) coupled with conditions of the repositories themselves (e.g. anoxia,radioactivity, high temperatures). Indigenous extremely halophilic archaea can survive long-term at high ionic strength and may remain viable throughout a repository´s lifetime. However, their ability to affect repository performance through waste and radionuclide transformation is uncertain, as they are mostly arobic and repositories are projected to be anoxic. Microorganisms introduced with waste may contribute to transformations within drums but may not survive high salt concentrations once drums have been breached and inundated with brine. However, both indigenous and introduced organisms may associate with radionuclides and enhance or mitigate radionuclide migration in this capacity.

Clays are commonly used in design concepts for geological disposal of nuclear waste. It is thus essential to identify and quantify microbial communities in clay-rich samples to study microbial processes during geological disposal. Although advances in culture-independent techiques have enablesd detailed studies of microbial communities in diverse ecosystems, the efficiency and sensitivity of these molecular techniques depend on chartacteristics of the environment studied. Moreover, the outcome of nucleic acid-based approaches depends on the extraction method, prmer specificity, PCR amplification, sequencing artefacts and downstream bioinformatic analyses. Clays are recalcitrant to DNA extraction and are challenging for analysis by standard techniques using viability stains and measurement of metabolic activity. This chapter explores the impact of various sequencing and bioinformatic pipelines used for 16S rRNA gene profiling of microbial communities and compares the efficiency of different DNA extraction methods from clay. Moreover, non-DNA based techniques used to assess microbial activity and viability in clay samples will be also discussed.

The Microbiology of Nuclear Waste Disposal is a state-of-the-art reference featuring contributions focusing on the impact of microbes on the safe long-term disposal of nuclear waste. This book is the first to cover this important emerging topic, and is written for a wide audience encompassing regulators, implementers, academics, and other stakeholders. The book is also of interest to those working on the wider exploitation of the subsurface, such as bioremediation, carbon capture and storage, geothermal energy, and water quality.

Planning for suitable facilities in the U.S., Europe, and Asia has been based mainly on knowledge from the geological and physical sciences. However, recent studies have shown that microbial life can proliferate in the inhospitable environments associated with radioactive waste disposal, and can control the long-term fate of nuclear materials. This can have beneficial and damaging impacts, which need to be quantified.

The dominant challenge of current copper beneficiation plants is the low recoverability of oxide copper-bearing minerals associated with sulfide type ones. Furthermore, applying commonly used conventional methodologies does not allow the interactional effects of critical parameters in the flotation processes to be investigated, which is mostly overlooked in the literature. To tackle this issue, the present paper aimed at characterizing the behavior of five key effective factors and their interactions in a sulfidized copper ore. In this context, dosage of collector (sodium di-ethydithiophosphate, 60–100 g/t), depressant (sodium silicate, 80–120 g/t) and frother (methyl isobutyl carbinol (MIBC), 6–10 g/t), pulp pH (7–11) and agitation rate (900–1300 rpm) were examined and statistically analyzed using response surface methodology. Flotation experiments were conducted in a Denver type agitated flotation cell at the rougher stage. The experimental results showed that increasing the pH (from 8 to 10) at low agitation rate (1000 rpm) enhanced the recovery from 80.36% to 85.22%, while at high agitation rate (1200 rpm), a slight declination occurred in the recovery. Meanwhile, increasing the collector dosage at a lower frother value (7 g/t), caused a reduction of about 4.44% in copper recovery owing to the interactions between factors, whereas at a higher frother level (9 g/t), the recovery was almost unchanged. The optimization process was also performed using the goal function approach, and maximum copper recovery of 92.75% was obtained using ~70 g/t collector, 110 g/t depressant, 7 g/t frother, pulp pH of 10 and 1000 rpm agitation rate.

Das Ziel des Teilvorhabens des HZDR war die thermodynamische, strömungstechnische und regelungstechnische Beschreibung und Auslegung des Gesamtsystems des DELTA-Reaktors. Mit Hilfe von geeigneten Simulationsmethoden sollte das Betriebsverhalten des räumlich und thermisch eng gekoppelten Reaktorkonzepts von Hochtemperaturelektrolyse sowie Methanolsynthese untersucht und die durch den Projektpartner TUD-WKET durchgeführten Arbeiten zur konstruktiven Gestaltung des Prozesses begleitet und unterstützt werden. Im Projektverlauf sollte außerdem gemeinsam mit dem Projektpartner TUD-WKET ein Mess- und regelungstechnisches Konzept entwickelt sowie ein geeignetes Analysengerät zur Bestimmung des Produktgasgemisches des Reaktionssystems ausgewählt, beschafft und in die experimentelle Versuchsplattform integriert werden. Darüber hinaus sollte im Rahmen des Teilprojektes ein Simulationsmodell auf Systemebene erstellt und das Verhalten des DELTA-Reaktors unter fluktuierenden Lasten beschrieben werden.