Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Hypothesis: Young contact angle is widely applied to evaluate liquid wetting phenomena on solid surfaces. For example, it gives a truncated-spherical shape prediction of a droplet profile through the Young-Laplace equation. However, recent measurements have shown deviations between microscopic droplet profiles and the spherical shape, indicating that the conventional Young contact angle is insufficient to describe microscopic wetting phenomena. In this work, we hypothesize that a liquid-gas interface nano-bending, which is caused by the nonlinear coupling between the effects of the microscopic interface geometry and solid-liquid interactions, is responsible for this deviation.
Simulation and theory: Using molecular dynamics simulations and mathematical modeling, we reveal the structure of the nano-bending and the mechanism of the nonlinear-coupled effect. We further apply our findings to illustrate a liquid microlayer with the saddle-shaped profile in nucleate boiling.
Findings: The nonlinear-coupled effect is responsible for the deviation of a nano-droplet profile and also the very thin microlayer captured by different experiments. The saddle-shaped interface significantly highlights the nonlinear-coupled effect. The interface nano-bending, rather than the Young contact angle, acts as the boundary condition and dictates the liquid wetting system, especially for the case with high interface curvature. These findings provide insight into recent nano-scale droplet- and bubble-related wetting phenomena.

We report on 3D lattice kinetic Monte Carlo (3DlkMC) simulation of nanostructure formation during rapid quenching in gas-atomization (up to 108K/s) of droplets of AlSi alloy melt. The nanostructured Si particles (with the Al selectively etched away) promise to enable about 10x the capacity of the current state-of-the-art graphite in lithium-ion batteries by mitigating Si pulverization.

This work reproduces the experimentally found nanosponge and core-shell particles and reveals heteronucleation at Al2O3 sites resulting from trace oxygen at the surface as the formation mechanism for core-shell particles.

The computer simulation uses a memory-efficient bit-encoded lattice, enabling large scale atomistic calculations, while kinetics is implemented via CPU-efficient bit-manipulation for atom jumps between lattice sites. The jump probabilities are described by the metropolis algorithm with a look-up-table of energies calculated with an angular dependent potential for the Si-Al-Au system in LAMMPS.

This work is supported by the federal ministry for economic affairs and climate protection under grant number 01221755/1.

Robis requires an Abstract, but this poster doesn't have one, so here's the one from a conference talk about the same contents:

We report on 3D lattice kinetic Monte Carlo (3DlkMC) simulation of nanostructure formation during rapid quenching in gas-atomization (up to 108K/s) of droplets of AlSi alloy melt. The nanostructured Si particles (with the Al selectively etched away) promise to enable about 10x the capacity of the current state-of-the-art graphite in lithium-ion batteries by mitigating Si pulverization.

This work reproduces the experimentally found nanosponge and core-shell particles and reveals heteronucleation at Al2O3 sites resulting from trace oxygen at the surface as the formation mechanism for core-shell particles.

The computer simulation uses a memory-efficient bit-encoded lattice, enabling large scale atomistic calculations, while kinetics is implemented via CPU-efficient bit-manipulation for atom jumps between lattice sites. The jump probabilities are described by the metropolis algorithm with a look-up-table of energies calculated with an angular dependent potential for the Si-Al-Au system in LAMMPS.

This work is supported by the federal ministry for economic affairs and climate protection under grant number 01221755/1.

This paper investigates the effect of an oil collector, namely diesel oil, on surface air nucleation and the influence of
nucleation microbubbles on collector adsorption in froth flotation. In order to prepare the condition for air nucleation in
flotation, air-oversaturated water was produced using tap water pressurized by high-pressure air in an autoclave. Microflotation,
single bubble collision experiments, contact angle measurements, microscopic observations, and agglomerations
analysis were combined to investigate the effects of the oil collector on air nucleation and agglomerates formation.
Furthermore, the free energy changes in an ideal system were utilized to explain the mechanisms. The experimental results
and free energy changes show that diesel oil can improve the air nucleation probability on graphite surfaces by decreasing
the barrier for nucleation. Meanwhile, the oil collector can also significantly increase the fraction of agglomerates formed in
air-oversaturated water to improve the recovery of fine particles. Besides, the results indicate that the formation of nucleation
microbubbles before collector conditioning can occupy significant surface areas of the graphite particles and inhibit the
collector adsorption on the mineral surfaces.

Ziel: Die Herstellung von 6-L-[18F]FDOPA durch elektrophile Radiomarkierung mit [18F]F2 Gas ist eine in Dresden-Rossendorf seit über 20 Jahren praktizierte Methode [1,2]. Mit der Inbetriebnahme eines neuen Zyklotrons TR-Flex und des F2-Gastargets 2018 musste die elektrophile Synthese von [18F]FDOPA angepasst werden.

We present measurement results for the flow rate of liquid sodium at temperatures up to 700 °C that were obtained with a high temperature prototype of an immersed Eddy Current Flow Meter. The experimental campaign was conducted at the SOLTEC-2 sodium loop at KIT. The main objective of the experiments is the high temperature qualification of the Eddy Current Flow Meter as part of the safety instrumentation of generation IV liquid metal cooled fast reactors. There it is intended to be used for monitoring the flow rate of the coolant and to detect possible blockages of sub assemblies. Due to the large liquid metal volume, the sensor has to be located close to the sub assemblies, therefore measurements from outside of the vessel are not possible and an immersed sensor is required. We demonstrate the successful application of the immersed Eddy Current Flow Meter at such high temperatures and identify the relevant effects with impact on the sensor performance.

Alpha particles emitted from actinides can cause lattice defects in crystalline solids. These affect surface reactivity of various reactions such as dissolution, growth or sorption1. Biotite is an important rock-forming mineral in a variety of igneous and metamorphic rocks that are considered for use as deep geological repositories. The frequent occurrence of biotite in host-rocks can quantitatively influence the retention of migrating radionuclides in the far field2. Therefore, understanding and quantifying the effects exposure to radionuclides can have on the sorbing capabilities of a crystal, will lead to an improved predictability of the far-field natural barriers upon which safe waste disposal relies. In this study, we investigate the formation of crystal defects in biotite and their influence on surface reactivity. For this, two pristine biotite samples were irradiated with and 4He3+ focused ion beam in order to induce crystal structural damage. This is an analogue to the situation of radionuclide release in the repository. The irradiation parameters were chosen to avoid amorphization and to focus on crystal defect development. The samples are them surface-controlled dissolved to finally quantify the defect density by using vertical scanning interferometry (VSI). Subsequently, the surface-modified biotite samples are used for sorption experiments witch actinide analogues such as 152EU3+. Comparison of the anticipated results will provide conclusions about the quantitative changes in reactive transport processes of actinide migration in sheet-bearing host rocks.

[18F]FTC-146 was introduced a decade ago as a very potent and selective sigma-1 receptor (σ1R) radioligand, which has shown promising application as an imaging agent for neuropathic pain with positron emission tomography (PET). In line with a multi-laboratory project on animal welfare, we chose this radioligand to investigate its potential for detecting neuropathic pain and tissue damage in tumor-bearing animals. However, the radiochemical yield (RCY) of around 4-7% was not satisfactory to us and efforts were made to improve it. Herein, we describe an improved approach for the radiosynthesis of [18F]FTC-146 resulting in a RCY, which is seven-fold higher than that recently reported by Shen et al. A tosylate precursor was synthesized and radio-fluorination experiments were performed via aliphatic nucleophilic substitution (SN2) reactions using either K[18F]F-Kryptofix®222 (K2.2.2)-carbonate system or tetra-n-butylammonium [18F]fluoride ([18F]TBAF). Several affecting reaction parameters such as solvent, 18F-fluorination agent with the corresponding amount of base, labeling time and temperature were investigated. Best labeling reaction conditions were found to be [18F]TBAF and acetonitrile as solvent at 100 °C. The new protocol was then translated to an automated procedure using a FX2 N synthesis module. Finally, the radiotracer could be reproducibly produced with a RCY of 41.7 ± 4.4% in high radiochemical purity (>98%) and molar activities up to 171 GBq/µmol.

KM is the process through which organizations generate value from their intellectual and knowledge-based assets 1.
Implementation of Knowledge Management (KM) is an important issue for all types of nuclear organizations and in particular for Radioactive Waste Management (RWM) organizations. Thus, the fundamental objective of RWM is to manage the radioactive waste without adverse impact for human health and the environment during its radioactive waste lifetime. Considering the life cycle of the radioactive waste it is obvious that KM accompanies Safety Management (SM). The management of radioactive waste affects future generations and covers pretreatment, treatment, conditioning, storage and disposal. At all mentioned stages operators are dealing with information such as take the records, use the standards & templates, prepare the reports. Without adequate knowledge it would be impossible to carry out this work and conclusively safety will be under risk. It is clear, that managing the knowledge must be implemented at all stages of RWM with the integration of knowledge processes concentrating on the following four core activities:

• To generate the knowledge
• To store the knowledge
• To share the knowledge
• To distribute the knowledge

• Information and Document Management
• Human Resource Management
• Knowledge Organizational Structure

However, depending on the organization (Regulatory, Operations, R&D organizations) involved in RWM the used KM methods & tools will be different. Nuclear R&D organizations can be categorized into seven types oriented on types of functions undertaken by the respective organization. In 2012 IAEA2 has classified them as follows: (1.) Basic research functions, (2.) Applied research functions, (3.) Design R&D functions, (4.) Functions utilizing nuclear R&D facilities, (5.) Functions utilizing non-nuclear R&D facilities, (6.) Educational R&D functions and (7.) Technical support & service functions.
Referring to R&D functions it becomes obvious that out of seven known Knowledge levels3 R&D organizations mainly use four (i.e. Organizational memory, Knowledge in Processes, Knowledge in Products & Services and Knowledge in People). An example for this is the KM initiatives in the Institute of Resource Ecology.
The Institute of Resource Ecology is one of eight institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) where many administrative tasks are centralized. For example the human resources (HR) department, the financial department, the international department and the IT department are all administrated centrally by the HZDR. The HZDR has an internal platform which is used for administrative work, data & information management, communication and keeps employees updated with ongoing and upcoming activities in their institutes. Beside this platform, HZDR employees use different IT tools, e.g. Outlook, Mattemost, etc, for close cooperation. The employees skill development program is administrated by the center. This program follows the requirements collected from all HZDR employees.
Continuous education and training programs for the HZDR employees and students, well organized in cooperation with partner organizations (TU-Dresden etc) do also support the knowledge capturing & sharing process.
The centralized library has more than 40.000 books in hard copy and 16.300 e-books & journals and all are available for employees of the center. The repository of HZDR’s publications has more than 36.000 scientific papers. In addition, each institute has also an internal scientific database for employee’s needs.
There are several formats of information and knowledge exchange in the Institute. To convince the employees of the importance of knowledge-sharing the institute provides series of different workshops regularly e.g. monthly seminars, workshops, department meetings, strategy and jour-fixe meetings in hybrid formats.
Obviously, the critical knowledge in the institute is linked to research works. The critical knowledge here is defined as knowledge which is needed to meet the objectives of the Institute. The critical knowledge holders are well known. There are several practices applied in the institute for maintaining the knowledge and transfer it. First of all to mention here is the supervision & mentoring program for the PhD students by critical knowledge holders. Another one is the procedure for uploading publications and records to the internal repository. There are also two inhouse scientific databases at the IRE available for internal and external users: (1.) RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics and database and (2.) the Thermodynamic Reference Database (THEREDA). However, there is still a high demand for the development of Knowledge Preservation programs. The loss of knowledge in association with the retirement of knowledge holders is still an issue in the institute. This is true for all nuclear organizations.
Different approaches have been used in industry. As an example, the approach applied by the Federal Company for Radioactive Waste Disposal (BGE) is described.
Due to the restructuring of the nuclear waste-management landscape in Germany, BGE is since 2017 the national competence centre in Germany and responsible for the disposal of radioactive waste.
For many decades, Research &Developement-work for this subject has been performed in Germany with an enormous stock of knowledge (topical and quantitative), but an overview is impaired due to the diffuse and local organisation of knowledge of the nuclear waste-management landscape.
Research reports for example can be found in many archives, but no archive is complete and „Old stock of knowledge“(old documents, grey literature) has to be embedded in the new stock of knowledge.
At the same time the imminent loss of expertise due to phasing out of nuclear energy production and mining in Germany must be considered as a limiting and partially critical factor, especially while reflecting the age structure of the BGE-staff and the restart of the new site selection procedure for disposal of highly radioactive waste products.
Facing these prerequisites the newly formed internal department for knowledge management (KM) of the BGE is establishing an infrastructure for KM and generates a connection between KM platforms and knowledge holders in the company to make explicit, implicit and tacit knowledge available.
The approach for the explicit knowledge is the provision of a digital information basis, into which current results from research and development are entered as a knowledge store. This knowledge store currently consists of more than 16.000 documents, mainly research reports and scientific publications, which are concerned with diverse topics for the final disposal of radioactive waste.
The total stock of available internal company documents can be accessed with a browser-based text analysis software. Intelligent search algorithms render the textual contents accessible, combine them with synonyms and dictionaries deposited in the system and make the resulting hits of the search queries available for the user in order of importance in summarized and full text versions.
Using specific query terms the software analyzes the available documents of the digital information basis and provides a brief description of the contents, the naming of relevant keywords, the identification of sources, compilers, institutions, knowledge carriers and an extended optimized information analysis of hits, as well as the possibility to access the complete document. The search options can be combined with established internet search engines as well as with queries of incorporated information or databank catalogue of national and international scientific institutions or libraries, which are concerned with research programs relevant for repositories4. The content volume of the digital information basis, as well as the amount of externally connected research sources is permanently growing.
To further increase and optimize the information possibilities for employees of the BGE and to make implicit knowledge partly available, a variety of general and demand-oriented interactive knowledge maps have been and will be implemented in the intranet, which enable specific queries on topics, expert information, etc.
To capture the tacit knowledge of persons who are leaving the company due to retirement, concerted concepts, e.g. interviews including transcriptions are used to make this individual knowledge available to the BGE-staff using the BGE internal tools for capturing and distributing implicit and explicit knowledge.
Additional actions contain, e.g. the initiation and organisation of technical and professional talks on various topics and to establish them as a permanent and important exchange possibility in the company.
While “How to use” seminars for the use of the broser-based text analysis software are already established and a permanent and reoccurring part in the company, further seminars and videos with “How to use” approach e.g. for demand-oriented interactice knowledge maps are in the implementations process as well as a Podcast series about Knowledge Management in the BGE.
For the further development of person-related and further group-related knowledge, the BGE Knowledge Management group/department is compiling concepts, which can only be implemented together with the employee in the company and its own guiding principles as they border on certain interfaces in the organization/company, taking into account that all measures to share and distribute knowledge can only be a permanent success if it is voluntarily process without compulsion.
By writing this paper we tried to illustrate the practical difference between KM initiatives in R&D and industry. However, the overlapping of the approaches at some certain stages are visible. The information management has been considered as an essential part of the knowledge management in both of organizations. The capture of the critical knowledge in both organizations remains a main issue even if the selected methods are different. The coaching & mentoring program which are well implemented at the IRE (HZDR), are may be difficult to realize/accomplish at the BGE. However, the pilot coaching program is planned at the BGE, but currently not available due to the “young” founding date in 2017. One of the main concerns of the BGE as an implementer, is the motivation and encouragement of all employees to share and distribute their knowledge and benefit from each other.

Reference:

1. SANTOSUS, MEGAN, and SURMACZ, The ABCs of Knowledge Management, Knowledge Management Research Center, accessed on 09 December 2005 at http://www.cio.com/research/knowledge/edit/kmabcs.html. )
2. IAEA, Knowledge Management for nuclear Research and Development organizations IAEA, Vienna, 2012
3. Jatinder N.D. Gupta, Sushil K. Sharma, Jeffrey Hsu, “An overview of Knowledge Management”, Knowledge management. I. Jennex, Murray E., 1956
4. Gunnar Hoefer, Sebastian Wanka, Peter L. Wellmann, Knowledge Management in the Federal Company for Radioactive Waste Disposal (BGE), Saf. Nucl. Waste Disposal, 1, 251–253, 2021

Purpose/Objective
The preparation for an online-adaptive replanning in proton therapy (OAPT), including e.g. daily anatomy assessment and contouring of relevant structures, can considerably prolong the treatment session. We therefore propose for the first time a concept of partial adaptation as a step towards near real-time OAPT: the first non-adapted field is delivered during the replanning process while the remaining adapted fields shall also compensate for the suboptimal dose from the first field. The dosimetric consequences are demonstrated for head and neck cancer (HNC) patients.

Materials/Methods
A partial adaptation workflow was implemented in RayStation (v.11.0.100) via the dose tracking module and the consideration of field-wise background dose. For six HNC patients, simultaneous integrated boost plans with three fields delivering 54Gy/66Gy to the low-risk/high-risk clinical target volume (CTVLow/CTVHigh) in 33 fractions were robustly optimized. Partially adapted fraction doses considering a non-adapted posterior field were generated on 3 control CTs (cCT) per patient, acquired in the first week, at mid of treatment and in the last week. Results were compared with doses from the non-adapted plan and from fully adapted plans on the cCT anatomy by analysing CTV coverage (D98%>95%), overdose (D1%) and organ at risk (OAR) sparing. Paired t-tests were used to indicate significant differences (p<0.05).

Results
In general, dose distributions from the partial and full adaptations/partial and full adaptation strategy were quite similar, while non-adapted plans resulted in different individual deficits (Fig.1).
In all 18 fractions (Fig.2), partial as well as full adaptation led to sufficient coverage of both CTVs without significant differences (median D98% for both strategies: 97.2%/98.5% for CTVLow/CTVHigh), while the D98% of non-adapted plans was significantly lower, even below 95% in 6 and 3 cases and had median values of 95.3% and 97.5% for CTVLow and CTVHigh, respectively. Hotspot dose D1%(CTVHigh) was above 105% in 6 cases for non-adapted and well below for adapted plans (median: 104%, 101.5% and 102.3% for no, partial and full adaptation).
Dose changes in OARs with respect to the initial plan were case dependent and usually within constraints. Absolute dose changes for D50%(parotid) and D1%(spinal cord) were significantly smaller for both partial and full adaptation compared to the non-adapted plans that led more often to relevant dose increase.
Conclusion
The new concept of partial adaptation was proven to compensate for the dosimetric influence of anatomic changes similarly well as fully adapted plans, especially in terms of restoring target coverage and reducing hotspots. It could therefore be used to shorten OAPT treatment sessions towards near real-time OAPT. Moreover, the same implementation of partial adaptation would be beneficial for online adaptations that are triggered by online treatment verification (e.g. by prompt gamma imaging) after the first non-adapted field delivery.

Radiomics analyses provide a promising avenue for enabling personalized radiotherapy. Most frequently, prognostic radiomics models are based on features extracted from medical images that are acquired before treatment. Here, we investigate whether combining data from multiple timepoints during treatment and additionally from multiple imaging modalities can improve the predictive ability of radiomics models.
We extracted radiomics features from computed tomography (CT) images acquired before treatment as well as two and three weeks after the start of radiochemotherapy for 55 patients with locally advanced head and neck squamous cell carcinoma (HNSCC). Additionally, we obtained features from FDG-PET images taken before treatment and three weeks after start of therapy. Cox proportional hazards models were then built based on features of the different image modalities, treatment timepoints and combinations thereof using two different feature selection methods in a five-fold cross-validation approach. Based on the cross-validation results, feature signatures were derived and their performance was independently validated. Discrimination regarding loco-regional control was assessed by the concordance index (C-index) and log-rank tests were performed to assess risk stratification.
The best prognostic performance was obtained for timepoints during treatment for all modalities. Overall, CT was the best discriminating modality with an independent validation C-index of 0.78 for week two and week two and three combined. However, none of these models achieved a statistically significant patient stratification. Models based on FDG features from week three provided both, satisfactory discrimination (C-index=0.61 and 0.64) and a statistically significant stratification (p=0.044 and p<0.001) but produced highly imbalanced risk groups.
After independent validation on larger data sets, the value of (multimodal) radiomics models combining several imaging timepoints should be prospectively assessed for personalized treatment strategies.

In this work, the capabilities of state-of-the-art turbulence models are compared for a three-dimensional flow (3D) field within a constricted vertical pipe. The considered flow domain is a vertical pipe section with a baffleshaped flow constriction which leads to the development of a jet flow through and a recirculation flow region behind the constriction. Different Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) models were tested for single- and two-phase flow simulations. In the two-phase simulations, bubble-induced turbulence (BIT) was also considered by adding source terms in the k and ε/ω equations. The results are validated against experimental data. We employed hot-film anemometry (HFA) for liquid velocity measurement and
combined it with ultrafast X-ray computed tomography (UFXCT), which provides gas phase data. Based on the local phase-indicator function obtained from the tomographic image data, we can correct HFA signals, which become corrupted by bubble contacts. We found that for single-phase flow all RANS models predict axial velocity well while radial velocity prediction is inadequate. LES models, however, achieve a better prediction of the latter. For two-phase flow, the axial component of the liquid velocity is well captured by all RANS models and the radial component of the liquid velocity is predicted better than for single-phase flow. In general, the computationally less costly RNG k-ε model performs similar to the SSG RSM model and can therefore be recommended for simulation of complex flow scenarios.

In this presentation, I will review our recent activities on flexible and printed magnetic field sensorics.

High dielectric constant materials are of particular current interests as indispensable components in transistors, capacitors, etc. In this context, there are emerging trends to exploit defect engineering in dielectric ceramics for enhancing the performance. However, demonstrations of similar high dielectric performance in integration-compatible crystalline films are rare. Herein, such a breakthrough via the functionalization of donor–acceptor dipoles by compositional tuning in GaCu codoped ZnO films is reported. The dielectric constant reaches ~200 at 1 kHz and the optical transmittance in visible light reaches ~80%. Importantly, by analyzing the impedance spectroscopy data, prominent relaxation mechanisms in correlation with the dipole properties, enabling consistent explanations of the dielectric constant as a function of frequency are discriminated. The atomistic nature of the dipoles is revealed by the systematic X-ray spectroscopy analysis. Spectacularly, similar trends for the dielectric properties are observed, while synthesizing samples by pulsed laser deposition and ion implantation, indicating the general character of the phenomena.

The potential of time-of-flight recoil detection for sensitive multi-element profiling of thin membranes and quasi-2D systems in transmission geometry using pulsed keV ion beams is assessed. While the time-of-flight approach allows for simultaneous detection of multiple elements, to the largest extent irrespective of recoil charge states, the keV projectile energies guarantee high recoil-cross sections yielding high sensitivity at low dose. We demonstrate the capabilities of the approach using 22Ne and 40Ar as projectiles transmitted through thin carbon foils featuring optional LiF-coatings and single-crystalline silicon membranes for different sample preparation routines and crystal orientations.
Using a large position-sensitive detector (0.13 sr), a depth resolution below 6 nm and sensitivity below 1014 atoms/cm2 was achieved for H in a 50 nm thick silicon membrane. For crystalline targets, we show how the probability of creation and detection of recoils and their observed angular distribution depend on sample orientation.

Transition metal oxides have been extensively explored as novel catalysts for designing electrochemical sensors, but the underlying structure-activity relationship remains poorly understood. Herein, we explore a diverse chemical range of La_1-xSr_xFeO₃ perovskite oxides by evaluating their electrochemical sensing activity toward heavy metals and by determining their electronic structures using density functional theory. We find that tuning perovskite chemistry plays an important role in determining the electrochemical activities and sensitivities, as well as the valence states of Fe. By combining experimental and theoretical analyses, a linear relationship between the Fe−O covalency and the electrochemical activity and sensitivity has been obtained, where LaFeO₃ exhibits the highest activity of 109 mA cm_oxide ^-2.Thus, the Fe−O covalency is proposed as a rational activity descriptor for the electrochemical sensing of heavy metals. A novel solid-state gelation method was further developed for the fabrication of perovskite oxide aerogels, based on which a highly efficient electrochemical sensor was constructed with a high sensitivity of 87.06 μM μA^-1 and a low detection limit of 1.7 nM. This work unlocks an effective parameter, that is, Fe−O covalency, for rationally designing Fe-based oxides and deepening the understanding of fundamental parameters to develop highly efficient sensing platforms.

The talk gives insights into automated data and software publications. In this context, the HMC projects HELIPORT and HERMES are introduced and our path to a seamlessly interlinked research data and software ecosystem at the HZDR is shown.

One-pot chemical vapor deposition (CVD) growth of large-area Janus SeMoS monolayers is reported, with the asymmetric top (Se) and bottom (S) chalcogen atomic planes with respect to the central transition metal (Mo) atoms. The for- mation of these !D semiconductor monolayers takes place upon the thermo- dynamic-equilibrium-driven exchange of the bottom Se atoms of the initially grown MoSe! single crystals on gold foils with S atoms. The growth process is characterized by complementary experimental techniques including Raman and X-ray photoelectron spectroscopy, transmission electron microscopy, and the growth mechanisms are rationalized by first principle calculations. The remark- ably high optical quality of the synthesized Janus monolayers is demonstrated by optical and magneto-optical measurements which reveal the strong exciton– phonon coupling and enable an exciton g-factor of −3.3.

Prostate-specific membrane antigen (PSMA) binding tracers are promising agents for the targeting of prostate tumors. To further optimize the clinically established radiopharmaceutical PSMA-617, novel PSMA ligands for prostate cancer endoradiotherapy were developed. A series of PSMA binding tracers that comprise a benzyl group at the chelator moiety were obtained by solid-phase synthesis. The compounds were labeled with 68Ga or 177Lu. Competitive cell-binding assays and internalization assays were performed using the cell line C4-2, a subline of the PSMA positive cell line LNCaP (human lymph node carcinoma of the prostate). Positron emission tomography (PET) imaging and biodistribution studies were conducted in a C4-2 tumor bearing BALB/c nu/nu mouse model. All 68Ga-labeled ligands were stable in human serum over 2 h; 177Lu-CA030 was stable over 72 h. The PSMA ligands revealed inhibition potencies [Ki] (equilibrium inhibition constants) between 4.8 and 33.8 nM. The percentage of internalization of the injected activity/10^6 cells of 68Ga-CA028, 68Ga-CA029, and 68Ga-CA030 was 41.2 ± 2.7, 44.3 ± 3.9, and 53.8 ± 5.4, respectively; for the comparator 68Ga-PSMA-617, 15.5 ± 3.1 was determined. Small animal PET imaging of the compounds showed a high tumor-to-background contrast. Organ distribution studies revealed high specific uptake in the tumor, that is, approximately 34.4 ± 9.8% of injected dose per gram (%ID/g) at 1 h post injection for 68Ga-CA028. At 1 h p.i., 68Ga-CA028 and 68Ga-CA030 demonstrated lower kidney uptake than 68Ga-PSMA-617, but at later time points, kidney time-activity curves converge. In line with the preclinical data, first diagnostic PET imaging using 68Ga-CA028 and 68Ga-CA030 revealed high-contrast detection of bone and lymph node lesions in patients with metastatic prostate cancer. The novel PSMA ligands, in particular CA028 and CA030, are promising agents for targeting PSMA-positive tumor lesions as shown in the preclinical evaluation and in a first patient, respectively. Thus, clinical translation of 68Ga-CA028 and 68Ga/177Lu-CA030 for diagnostics and endoradiotherapy of prostate cancer in larger cohorts of patients is warranted.

We investigate shock-compressed copper in the warm dense matter regime by means of density functional theory molecular dynamics simulations. We use neural-network-driven interatomic potentials to increase the size of the simulation box and extract thermodynamic properties in the hydrodynamic limit. We show the agreement of our simulation results with experimental data for solid copper at ambient conditions and liquid copper near the melting point under ambient pressure. Furthermore, a thorough analysis of the dynamic ion-ion structure factor in shock-compressed copper is performed and the adiabatic speed of sound is extracted and compared with experimental data.

In our recent work [L. Körber, AIP Advances 11, 095006 (2021)], we presented an efficient numerical method to compute dispersions and mode profiles of spin waves in waveguides with translationally invariant equilibrium magnetization. A finite-element method (FEM) allowed to model two-dimensional waveguide cross sections of arbitrary shape but only finite size. Here, we extend our FEM propagating-wave dynamic-matrix approach from finite waveguides to the important cases of infinitely-extended mono- and multilayers of arbitrary spacing and thickness. To obtain the mode profiles and frequencies, the linearized equation of motion of magnetization is solved as an eigenvalue problem on a one-dimensional line-trace mesh, defined along the normal direction of the layers. Being an important contribution in multilayer systems, we introduce interlayer exchange into our FEM approach. With the calculation of dipolar fields being the main focus, we also extend the previously presented plane-wave Fredkin-Koehler method to calculate the dipolar potential of spin waves in infinite layers. The major benefit of this method is that it avoids the discretization of any non-magnetic material like non-magnetic spacers in multilayers. Therefore, the computational effort becomes independent on the spacer thicknesses. Furthermore, it keeps the resulting eigenvalue problem sparse, which therefore, inherits a comparably low arithmetic complexity. As a validation of our method (implemented into the open-source finite-element micromagnetic package \textsc{TetraX}), we present results for various systems and compare them with theoretical predictions and with established finite-difference methods. We believe this method offers an efficient and versatile tool to calculate spin-wave dispersions in layered magnetic systems.

Rapidly developing additive technologies for metallic parts production have led to the development of a wide range of methods supporting this field, including mechanical properties characterization. Components produced by AM processes are built spot to spot and layer by layer and that leads to varying local heat absorption and distribution, resulting in varying local properties depending on the shape complexity and build parameters. Different properties in different directions and at various component locations can be expected. Since AM parts are often sub-scale and/or with topological complexity, mechanical characterization with the use of standard specimens is not typically possible and small-sized specimen techniques have to be developed and applied. In the current paper, three AM produced parts made of Ti-6Al-4V by Electron Beam Powder Bed Fusion (EB-PBF) technology have been investigated. Three material conditions are reported here: as-deposited, stress relieved and HIP-ed. Local mechanical properties are assessed with the use of miniaturized compact tension (MCT) fracture toughness specimens and miniaturized tensile tests (MTT). The results are complemented by microstructural and fractographic analysis and are discussed in the light of literature values. © 2022 Elsevier Ltd

Focused ion beam (FIB) processing with low-energy ions has become a standard technique for the manipulation of nanostructures. Many underlying ion beam effects that deviate from conventional high-energy ion irradiation of bulk systems are considered today; however, ion channeling with its consequence of significant deeper penetration depth has been only theoretically investigated in this regime. We present here an experimental approach to determine the channeling of low-energy ions in crystalline nanoparticles by measuring the sputter yield derived from scanning electron microscopy (SEM) images taken after irradiation under various incident ion angles. Channeling maps of 30 and 20 keV Ga+ ions in Ag nanocubes have been identified and fit well with the theory. Indeed, channeling has a significant impact on the transport of energetic ions in crystals due to the large critical angle at low ion energies, thus being relevant for any FIB-application. Consequently, the obtained sputter yield clearly differs from amorphous materials; therefore, it is recommended not to rely only on, e.g., ion distribution depths predicted by standard Monte-Carlo (MC) algorithms for amorphous materials.

Purpose: The physical integration of MRI with proton therapy (PT) into an MR-integrated PT (MRiPT) system is expected to improve the targeting accuracy of PT. The purpose of this project was to develop a prototype system combining a low-field in-beam MRI scanner with a proton pencil beam scanning (PBS) beamline to enable a first MRiPT treatment. This contribution presents first results of the installation and commissioning of the MRiPT system where the positioning reproducibility, magnet shimming performance and image quality with a focus on geometric fidelity were analyzed.

Methods: The MRiPT setup consists of an open C-shaped 0.32 T MRI scanner (MRJ3300, ASG Superconductors SpA, Genoa, Italy) positioned in close proximity of the nozzle of a horizontal proton PBS beamline (Figure 1). The MRI scanner was encased in a custom-designed compact aluminum Faraday cabin. At the location of the beam exit window of the nozzle, a beam entrance opening was incorporated in the wall of the RF cabin, which was sealed by a thin (30 µm) aluminum foil to combine high RF attenuation and small lateral spreading of the traversing proton beam. The scanner and RF cabin were mounted on top of an air-cushion-based transport platform, allowing the assembly to be accurately positioned in the beam path exiting the nozzle. The maneuvering of the assembly into treatment position was thereby visually guided based on room lasers that intersect at the beam isocenter and project onto the outer wall of the cabin. The magnet was shimmed in treatment position close to ferromagnetic components of the nozzle where the B0 field homogeneity was measured using a magnetic field camera (MFC3045, Metrolab Technology SA, Geneva, Switzerland). During commissioning the MR image quality was assessed using the ACR Small MRI Phantom (American College of Radiology, Virginia, USA) with T1w spin echo (SE) imaging, and the CIRS MRI-LINAC Dynamic Phantom (Computerized Imaging Reference Systems Inc., Norfolk, USA) with a T1w 3D spoiled gradient echo (GFE) pulse sequence dedicated for patient positioning control in the MRiPT workflow. The phantom allows for distortion analysis with 4 grid layers consisting of 5 concentric circles.

Results: The positioning accuracy and precision of the mobile in-beam MRI system were below 1 mm. A peak-to-peak B0 field homogeneity of 43 ppm over a 25 cm diameter spherical volume (DSV) around the MR magnetic isocenter was achieved during shimming. The ACR QA protocol revealed a signal-to-noise ratio (SNR) of >80 and a geometric distortion of <1.5 mm over a 10 cm DSV around the magnetic isocenter. The CIRS distortion measurement using the 3D GFE sequence showed that geometric distortion increased up to <8 mm at 20 cm DSV and <11 mm at 24 cm DSV.

Conclusion: A 0.32 T in-beam MRI scanner was successfully installed and commissioned in front of a horizontal proton PBS beamline in preparation for the development of a first prototype MRiPT system. Large volume image distortion measurements showed the necessity for geometric distortion correction algorithms in order to facilitate an accurate image guidance in a future MRiPT treatment.

Purpose: Magnetic resonance imaging-integrated proton therapy (MRiPT) is considered a next step in advancing image guidance for proton therapy as it is expected to improve the targeting precision. However, the presence of the MR magnetic field poses a challenge to the dose delivery due to the Lorentz force affecting the proton beam path. This study aims to investigate the dosimetric impact of the static magnetic (B0) field of an in-beam MR scanner on the delivery of scanned proton pencil beams.
Methods: An MRiPT prototype comprising a horizontal pencil beam scanning beamline and an open 0.32 T in-beam MR scanner with a B0 field oriented perpendicular to the central beam axis was used to measure the 2D dosimetric impact of the B0 imaging and fringe field on proton beam transport. Beam transmission measurements in-air were conducted for three proton energies (100, 150, and 220 MeV) and two spot maps (15×15 cm² and 30×20 cm²). 2D relative dose spot profiles were measured with EBT3 films placed vertically in the imaging field (position Pisoc) without and with the B0 field. Pisoc was located centrally in the imaging volume at 58.2 cm and 122.4 cm downstream of the beam isocenter and exit window, respectively. A 2D Gaussian fit was applied to each dose spot to determine its central position (X, Y), minimum and maximum lateral standard deviation (σ_min and σ_max), orientation (θ), and eccentricity (ε).
Results: Three concurrent effects were observed: (a) lateral beam deflection of all spots, (b) asymmetric trapezoidal deformation of the radiation field (Figure 1), and (c) deformation and rotation of individual dose spots. The lateral deflection was energy-dependent and consistent for both field sizes within the uncertainty of the measurements (Table 1). The field deformation was more pronounced for the 30×20 cm² field than for the 15×15 cm² field, indicating a field size dependence. At Pisoc for the 15×15 cm² field size 100 MeV beams the σ_max decreased by up to 3.66%, while σ_min increased by a maximum of 2.15%. The dose spot eccentricity underwent minor changes with a maximum decrease and increase in ε of 0.08 and 0.02, respectively. The spot orientation changed by a maximum θ of 5.39°. Similar effects were observed at the higher proton energies but to a lesser extent.
Conclusions: For the first time, the 2D dosimetric impact of scanned proton pencil beams traversing the B0 imaging and fringe field of an in-beam MR prototype on the proton beam path, radiation field shape, and dose spot form has been measured in air. The results demonstrate the complex energy- and position-dependent transport behaviour of the pencil beams that requires the 3D B0 field to be taken into account by future MRiPT treatment planning systems. Further investigations are mandatory to assess the dosimetric effects of the B0 field on proton beams delivered with range shifters positioned inside the B0 field and on beams delivered in homogeneous and inhomogeneous target volume media.

Purpose: In magnetic resonance imaging-integrated proton therapy (MRiPT), the magnetic field-dependent change in the dosage of ionisation chambers is considered by the correction factor k_(B ⃑,M,Q), which can be determined experimentally or computed via Monte Carlo (MC) simulations. In this work, k_(B ⃑,M,Q) for a plane-parallel ionisation chamber was determined by measurements and MC simulations were used to reproduce these results with high accuracy.
Material/Methods: The dose-response of the advanced Markus chamber (TM34045, PTW, Freiburg, Germany) irradiated with homogeneous 10x10 cm² mono-energetic fields, using 103.3, 153.1, and 252.7 MeV proton beams was measured in a water phantom placed in the magnetic field (MF) of an electromagnet with MF strengths of 0.32 and 1 T. The detector was positioned at a 2 cm water-equivalent depth with chamber electrodes parallel to the MF lines and perpendicular to the proton beam incidence direction. The measurements were compared with TOPAS MC simulations utilizing COMSOL-calculated 0.32 and 1 T MF maps of the electromagnet. k_(B ⃑,M,Q) was calculated for the measurements for all energies and MF strengths based on the equation: k_(B ⃑,M,Q)= M_Q/(M_Q^B ⃑ ), where M_Q and M_Q^B ⃑ were the temperature and air pressure corrected detector readings without and with MF, respectively. MC-based correction factors were determined as k_(B ⃑,M,Q)= D_det/(D_det^B ⃑ ), where D_det and D_det^B ⃑ were the doses deposited in the air cavity of the ionisation chamber model without and with MF, respectively.

Results: The detector showed a reduced dose-response for all measured energies, and MF strengths resulting in experimentally determined k_(B ⃑,M,Q) values larger than 1 (Figure 1). k_(B ⃑,M,Q) increased with proton energy and MF strength, except for 0.32 T and 252.7 MeV. Overall, k_(B ⃑,M,Q) ranged between 1.006 ± 0.004 and 1.021 ± 0.010 for all energies and MF strengths examined and the strongest dependence on energy was found at 1 T. The MC simulated k_(B ⃑,M,Q) values for 0.32 and 1 T showed a good agreement with the experimentally determined correction factors and trends within their standard deviations. The maximum difference between experimentally determined and MC simulated k_(B ⃑,M,Q) values was 0.63%.
Conclusion: For the first time, measurements and simulations were compared for an advanced Markus chamber for the dosimetry of protons within MFs. For both MF strengths, there was a good agreement of k_(B ⃑,M,Q) between experimentally determined and MC calculated values in this study. By benchmarking the MC code for calculation of〖 k〗_(B ⃑,M,Q) it can be used to calculate 〖 k〗_(B ⃑,M,Q) for various ionisation chamber models, MF strengths and proton energies in order to generate data needed for a dosimetry protocol for MRiPT.

First-principle calculations are performed to investigate Y substitutional defects at ground state and at 1000 K, for Ba- and Zr-rich chemical environments. In dependence on the Fermi level, at ground state singly positively charged Y may be potentially stable on Ba site (YBa1+) and neutral as well as singly negatively charged Y on Zr site ( YZr0 and YZr1-). However, using recent results for the doubly positively charged oxygen vacancy (VO2+) and taking account charge compensation, Fermi level pinning occurs, so that under Ba-rich conditions YZr1- and VO2+ are really stable. A similar consideration yields YBa1+ and YZr1- as stable defects in the Zr-rich case. Concerning VO2+, which occurrence is a prerequisite to obtain a good proton conductor, by Y doping, at ground state only in the Ba-rich case a moderate concentration can be formed. At 1000 K the situation is improved importantly. The consideration of vibrational contributions to the free formation energy of Y on Zr site shows an increase of the stability of YZr0 and YZr1-. Under Ba-rich conditions Fermi level pinning results in a free formation energy for VO2+ of 0.481 eV which corresponds to a high VO2+ concentration and optimum conditions for proton conduction. In Zr-rich case the respective value is 0.863 eV which leads also to relatively high VO2+ occurrence but the situation is somewhat less favourable than for the Ba-rich environment.

Background: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biannual highlight commentary to update the readership on trends in the field of radiopharmaceutical development.
Main body: This commentary of highlights has resulted in 21 different topics selected by each coauthoring Editorial Board member addressing a variety of aspects ranging from novel radiochemistry to first in man application of novel radiopharmaceuticals.
Conclusion: Trends in radiochemistry and radiopharmacy are highlighted demonstrating the progress in the research field in various topics including new PET-labelling methods, FAPI-tracers and imaging, and radionuclide therapy being the scope of EJNMMI Radiopharmacy and Chemistry.

When materials are exposed to X-ray pulses with sufficiently high intensity, various nonlinear
effects can occur. The most fundamental one consists of stimulated electronic decays after
resonant absorption of X-rays. Such stimulated decays enhance the number of emitted
photons and the emission direction is confined to that of the stimulating incident photons
which clone themselves in the process. Here we report the observation of stimulated reso-
nant elastic (REXS) and inelastic (RIXS) X-ray scattering near the cobalt L3 edge in solid Co/
Pd multilayer samples. We observe an enhancement of order 106 of the stimulated over the
conventional spontaneous RIXS signal into the small acceptance angle of the RIXS spectro-
meter. We also find that in solids both stimulated REXS and RIXS spectra contain con-
tributions from inelastic electron scattering processes, even for ultrashort 5 fs pulses.
Our results reveal the potential and caveats of the development of stimulated RIXS in
condensed matter.

Polyalanine molecules (PA) with an α-helix conformation have recently attracted a great deal of interest, as the propagation of electrons through the chiral backbone structure comes along with spin polarization of the transmitted electrons. By means of scanning tunneling microscopy and spectroscopy under ambient conditions, PA molecules adsorbed on surfaces of epitaxial magnetic Al2O3/Pt/Au/Co/Au nanostructures with perpendicular anisotropy were studied. Thereby, a correlation between the PA molecules ordering at the surface with the electron tunneling across this hybrid system as a function of the substrate magnetization orientation as well as the coverage density and helicity of the PA molecules was observed. The highest spin polarization values, P, were found for well-ordered self-assembled monolayers and with a defined chemical coupling of the molecules to the magnetic substrate surface, showing that the current-induced spin selectivity is a cooperative effect. Thereby, P deduced from the electron transmission along unoccupied molecular orbitals of the chiral molecules is larger as compared to values derived from the occupied molecular orbitals. Apparently, the larger orbital overlap results in a higher electron mobility, yielding a higher P value. By switching the magnetization direction of the Co layer, it was demonstrated that the non-spin-polarized STM can be used to study chiral molecules with a submolecular resolution, to detect properties of buried magnetic layers and to detect the spin polarization of the molecules from the change in the magnetoresistance of such hybrid structures.

We systematically analyze the influence of 5 nm thick metal interlayers inserted at the interface of several sets of different metal-dielectric systems to determine the parameters that most influence interface transport. Our results show that despite the similar Debye temperatures of Al2O3 and AlN substrates, the thermal boundary conductance measured for the Au/Al2O3 system with Ni and Cr interlayers is ∼2× and >3× higher than the corresponding Au/AlN system, respectively. We also show that for crystalline SiO2 (quartz) and Al2O3 substrates having highly dissimilar Debye temperature, the measured thermal boundary conductance between Al/Al2O3 and Al/SiO2 are similar in the presence of Ni and Cr interlayers. We suggest that comparing the maximum phonon frequency of the acoustic branches is a better parameter than the Debye temperature to predict the change in the thermal boundary conductance. We show that the electron–phonon coupling of the metallic interlayers also alters the heat transport pathways in a metal-dielectric system in a nontrivial way. Typically, interlayers with large electron–phonon coupling strength can increase the thermal boundary conductance by dragging electrons and phonons into equilibrium quickly. However, our results show that a Ta interlayer, having a high electron–phonon coupling, shows a low thermal boundary conductance due to the
poor phonon frequency overlap with the top Al layer. Our experimental work can be interpreted in the context of diffuse mismatch theory and can guide the selection of materials for thermal interface engineering.

Not only since the progressive reduction of structure sizes in modern micro- and nanotechnology, surface and interface effects have played an ever-increasing role and nowadays often dominate the behavior of entire systems. Therefore, understanding the nature of surface and interface effects and being able to fully control them is of fundamental importance, in particular in modern thin-film technology. In this study, it is revealed how Co/Pt multi-layer-based synthetic antiferromagnets (SAFs) with perpendicular magnetic anisotropy in the regime of dominating antiferromagnetic interlayer exchange can be employed to control the collective magnetic reversal via systemati-cally altering surface and interface effects. The specifically designed samples and experiments highlight the superior tunability of synthetic systems as compared to their intrinsic stoichiometric counterparts, where the antiferro-magnetism is directly tied to the indivisible discrete atomic nature and crystal structure of the materials. Thus, it is demonstrated that in SAFs, it becomes possible to energetically heal the broken magnetic symmetry at the surface, thereby enabling either on demand suppression or controlled enhancement of respective surface and interface effects, as demonstrated here in this study for the surface spin-flop and the exchange bias effect.

Intercalation of very long molecules into the structure of multi-layered graphene oxide was studied using example of 1-hexadecanol (C16), an alcohol molecule with 16 carbon atoms and length of about 22Å. Brodie graphite oxide (BGO) immersed in excess of liquid 1-hexadecanol just above the melting point shows expansion of c-unit cell parameter from ~6Å to ~48.76 Å forming a structure with two densely packed layers of C16 molecules in a vertical “stand up” orientation relative to graphene oxide planes (α-phase). Heating of the BGO-C16 α-phase in excess of C16 melt results in reversible phase transition into β-phase at 336-342K. The β-phase shows much smaller c-unit cell of 29.83 Å (363K). Analysis of data obtained using vacuum-driven evaporation of C16 from the β-phase and set of experiments with samples pre-mixed with different BGO:C16 proportions provides evidence for structure of β-phase consisting of five layers of C16 molecules in parallel to GO plane orientation. Therefore, the transition from α- to β- phase corresponds to change in orientation C16 molecules from vertical to parallel to GO planes and significant decrease in amount of intercalated solvent. Cooling of β-phase in absence of C16 melt is found to result in the formation of γ-phase with interlayer distance of ~26.5Å. This distance corresponds to one layer of C16 molecules intercalated in vertical relative to GO planes orientation. Finally, structures with one and two layers of C16 molecules parallel to GO planes were identified in samples with rather small initial loading of C16. Surprisingly rich variety of structures revealed in BGO-C16 system provides opportunities to create materials with precisely controlled GO inter-layer distance.

Extracellular matrix (ECM) provides various types of direct interactions with cells and a dynamic environment, which can be remodeled through different assembly/degradation mechanisms to adapt to different biological processes. Herein, through introducing polyphosphate-modified hyaluronic acid and bioactive glass (BG) nano-fibril into a self-assembled hydrogel system with peptide-polymer conjugate, we can realize many new ECM-like functions in a synthetic polymer network. The hydrogel network formation is mediated by coacervation, followed by a gradual transition of peptide structure from α-helix to β-sheet. The ECM-like hydrogels can be degraded through a number of orthogonal mechanisms, including treatments with protease, hyaluronidase, alkaline phosphatase, and calcium ion. As 2D coating, the ECM-like hydrogels can be used to modify the planar surface to promote the adhesion of mesenchymal stromal cells, or to coat the cell surface in a layer-by-layer fashion to shield the interaction with the substrate. As ECM-like hydrogels for 3D cell culture, the system is compatible with injection and cell encapsulation. Upon incorporating fragmented electrospun bioactive glass nano-fibril into the hydrogels, the synergetic effects of soft hydrogel and stiff reinforcement nanofibers on recapitulating ECM functions result in reduced cell circularity in 3D. Finally, by injecting the ECM-like hydrogels into mice, gradual degradations over a time period of one month and high biocompatibility have been shown in vivo. The contribution of complex network dynamics and hierarchical structures to cell-biomatrix interaction can be investigated multi-dimensionally, as many mechanisms are orthogonal to each other and can be regulated individually.

Stacking various two-dimensional (2D) materials in van der Waals (vdW) het- erostructures is a novel approach to design new systems, which can host alkali metal (AM) atoms to tune their electronic properties or store energy. Using state-of-the-art first-principles calculations, we systematically study the intercalation of the most wide- spread AMs (Li, Na, K) into a graphene/MoS2 heterostructure. Contrary to previous work on the intercalation of AMs into various heterostructures based on 2D materials, we consider not only single-, but also multi-layer configurations of AM atoms. We assess the intercalation energetics for various concentrations of AM atoms, calculate charge transfer from AM atoms to the host system, and show that although interca- lation of AMs as single layer is energetically preferable, multi-layer configurations can exist at high concentrations of AM atoms. We further demonstrate that the transition of the MoS2 layer from the H to T ′ phase is possible upon Li intercalation, but not Na or K. Our findings should help to better understand the behavior of heterostructures upon AM atom intercalation and may stimulate further experiments aimed at the tai- loring of heterostructure properties and increasing the capacity of anode materials in AM ion batteries.

Using first-principles and analytical potential atomistic simulations, we study the production of defects in epitaxial graphene on SiC upon ion irradiation for ion types and energies accessible in helium ion microscope. We focus on graphene-SiC systems consisting of the buffer (zero) graphene layer and SiC substrate, as well as one (monolayer) and two (bilayer) additional graphene layers. We calculate the probabilities for single, double and more complex vacancies to appear upon impacts of energetic ions in each graphene layer as functions of He and Ne ion energies, and compare the data to those obtained for the free standing graphene. The results indicate that the role of substrate is minimal for He-ion irradiation with energies above 5 keV, which can be associated with a low sputtering yield from this system upon ion irradiation, as compared to common Si/SiO2 substrate. In contrast, SiC substrate has a significant effect on defect production upon Ne-ion irradiation. Our results can serve as a guide to the experiments on ion irradiation of epitaxial graphene to choose the optimum ion beam parameters for defect-mediated engineering of such systems, e.g., for creating nucleation centers to grow other two-dimensional materials, such as h-BN, on top of the irradiated epitaxial graphene.

The rising production of lithium-ion batteries (LIBs) due to the introduction of electric mobility as well as stationary energy storage devices demands an efficient and sustainable waste man-agement scheme for legislative, economic and ecologic reasons. One crucial part of the recycling of end-of-life (EOL) LIBs is mechanical processes, which generate material fractions for the pro-duction of new batteries or further metallurgical refining. In the context of safe and efficient processing of electric vehicles’ LIBs, crushing is usually applied as a first process step to open at least the battery cell and liberate the cell components. However, the cell opening method used requires a specific pretreatment to overcome the LIB’s hazard potentials. Therefore, the depend-ence on pretreatment and crushing is investigated in this contribution. For this, the energy input for liberation is determined and compared for different recycling strategies with respect to dis-mantling depth and depollution temperatures. Furthermore, the respective crushing product is analyzed regarding granulometric properties, material composition and liberation and decoat-ing behaviour depending on the pretreatment and grid size of the crushing equipment. Finer particles and components are generated with dried cells. Pyrolysis of cells, as well as high dis-mantling depths, do not allow to draw exact conclusions. The calculated and measured mass-specific mechanical energy input of different dismantling depths shows good accuracy. Consequently, trends for a successful separation strategy of the subsequent classifying and sort-ing processes are revealed, and recommendations for the liberation of LIBs are derived.

Exploiting the strong electromagnetic fields that can be supported by a plasma, high-power laser driven compact plasma accelerators enable generation of short, high-intensity pulses of high energy ions with special beam properties. These accelerators promise to expand the portfolio of conventional machines in many application areas. The maturation of laser driven ion accelerators from physics experiments to turn-key sources for these applications will rely on breakthroughs in both, generated beam parameters (kinetic energy, flux), as well as increased scrutiny on reproducibility, robustness and scalability to high repetition rate.
Recent developments at the high-power laser facility DRACO-PW enabled the production of polychromatic proton beams with unprecedented stability [1]. This allowed the first in vivo radiobiological study to be conducted using a laser-driven proton source [2]. Yet, the ability to achieve energies beyond the 100 MeV frontier is essential for many applications and a matter of ongoing research, mainly addressed by exploring advanced acceleration schemes like the relativistically induced transparency regime.
In this talk we report on experimental proton acceleration studies at the onset of relativistic transparency using linearly polarized laser pulses with peak intensities of 6x21 W/cm2 focused on thin, pre-expanded plastic foils. Combined hydrodynamic and 3D particle-in-cell simulations helped to identify the most promising target parameter range matched to the carefully measured prevailing laser contrast conditions. In a nutshell, the ultra-intense femtosecond pulse interaction induces large accelerating gradients and energy gain dominantly arising from significant space charge fields due to electron expulsion from the relativistic transparent target core followed by weaker post-acceleration in diffuse sheath fields at later times. A complex suite of particle and optical diagnostics allowed characterization of spatial and spectral proton beam parameters and the stability of the regime of best acceleration performance, yielding cut-off energies larger than 100 MeV in the best shots.

Exploiting the strong electromagnetic fields that can be supported by a plasma, high-power laser driven compact plasma accelerators enable generation of short, high-intensity pulses of high energy ions with special beam properties. These accelerators promise to expand the portfolio of conventional machines in many application areas. The maturation of laser driven ion accelerators from physics experiments to turn-key sources for these applications will rely on breakthroughs in both, generated beam parameters (kinetic energy, flux), as well as increased scrutiny on reproducibility, robustness and scalability to high repetition rate.
Recent developments at the high-power laser facility DRACO-PW enabled the production of polychromatic proton beams with unprecedented stability [1]. This allowed the first in vivo radiobiological study to be conducted using a laser-driven proton source [2]. Yet, the ability to achieve energies beyond the 100 MeV frontier is essential for many applications and a matter of ongoing research, mainly addressed by exploring advanced acceleration schemes like the relativistically induced transparency regime.
In this talk we report on experimental proton acceleration studies at the onset of relativistic transparency using linearly polarized laser pulses with peak intensities of 6x21 W/cm2 focused on thin, pre-expanded plastic foils. Combined hydrodynamic and 3D particle-in-cell simulations helped to identify the most promising target parameter range matched to the carefully measured prevailing laser contrast conditions. In a nutshell, the ultra-intense femtosecond pulse interaction induces large accelerating gradients and energy gain dominantly arising from significant space charge fields due to electron expulsion from the relativistic transparent target core followed by weaker post-acceleration in diffuse sheath fields at later times. A complex suite of particle and optical diagnostics allowed characterization of spatial and spectral proton beam parameters and the stability of the regime of best acceleration performance, yielding cut-off energies larger than 100 MeV in the best shots.

An energy storage (ES) system is an economical and reliable technology that plays a
predominant role in making the renewable energy sector sustainable. Integration of ES with
wind and solar plants provides solution to problem of grid instability caused by to fluctuating
power output. The Thermal Energy Storage (TES) system is simple and has low environmental
and social impacts compared to other ES technologies like batteries, pumped hydro,
compressed air and chemical storage. However, application of a TES at high temperature is
quite unexplored and has a limited deployment globally.
Solid sensible TES (STES) stores excess electricity in form of sensible heat, the solid medium
is directly electrical heated or indirectly heated using heat transfer fluids (HTF). In STES
systems, no phase change nor chemical reactions involved. Hence, it is simple, easy to
maintain and the cost of construction materials is low. The foresaid advantages makes it
suitable for high temperature applications provided the solid material selected exhibits higher
temperature stability.
The poster will highlight the thermal performance of STES for 10 MWth power output over 24
hours, resulting in a storage capacity of 240 MWhth at high temperature of 800 °C. The
candidates of investigation are most commonly used solid materials, like high temperature
ceramic, high temperature concrete, firebricks, alferrock as well as vitrified flyash and as HTFs
Air, He, CO2 and N2 were studied. The influence of geometry, flow rate, heat transfer surface
area and solid material configuration in storage tank on the thermodynamics of TES system
cannot be ignored. Therefore, different STES designs were also included for assessment in
this research work.
To investigate the thermal performance of a STES system in terms of all the above-mentioned
candidates, a One-dimensional model will be developed in MATLAB and validated with data
available in literature. Based on results, the performance parameters like solid temperature
during charging/discharging cycle as well as overall thermal efficiency are evaluated. In addition, the economical assessment of different TES designs and materials can be estimated in €/MWhth.

The talk will start with an overview on the working principle of the all-liquid Na-Zn molten salt battery. Thereafter, various fluid dynamic effects, which might appear in such cells, will be discussed.

A single qutrit with transitions selectively driven by weakly-coupled reservoirs can implement one of the world's smallest refrigerators. We analyze the performance of N such fridges that are collectively coupled to the reservoirs. We observe a quantum boost, manifest in a quadratic scaling of the steady-state cooling current with N. As N grows further, the scaling reduces to linear, since the transitions responsible for the quantum boost become energetically unfavorable. Fine-tuned inter-qutrit interactions may be used to maintain the quantum boost for all N and also for not-perfectly collective scenarios.

Cutting fluids are usually applied during milling to reduce the friction and to protect the tool and the material from corrosion. These fluids are associated with toxicity and environmental problems. Moreover, the waste management of cutting fluids entails large expenses. The need to reduce cutting fluids has fostered the use of alternative coolants such as supercritical (sc) CO₂, alone or with minimum quantity lubrication (MQL). sc CO₂ and sc CO₂ + MQL coolants have been studied for face milling of a cold worked (CW) AISI 316L stainless steel (SS), evaluating their effect on the residual stresses generated in the surface, in the outermost microstructure of this material, and the corrosion performance. Furthermore, they are compared with those caused by traditional face milling and with a manually ground-generated surface. Ultrafine grain (UFG) layers of about 1 μm and passive layers (of similar chemical compositions) are identified for all the surfaces under study. The three milling processes under study generate a deformation layer under the UFG layer that does not appear below ground surfaces. Moreover, the preexistent compressive stresses created by the CW process change into tensile, being higher for the alternative green machining processes than for the traditional one. The probability of undergoing pitting (studied with cyclic polarization curves) appears to be linked to the nature and structure of the passive layer (characterized by Auger spectroscopy and Mott–Schottky analyses, respectively). Electrochemical impedance spectroscopy studies also confirm similar electrochemical performances for all analyzed surfaces. The active-to-passive transitions of the SS, which have been characterized by electrochemical potentiodynamic reactivation tests, appear to be related to the stresses and deformation state of the deformed layers. Passivation on the alloy in acid media appears to be favored after the sc CO₂ and sc CO₂ + MQL alternative milling processes than after traditional face milling and grinding.

Motion sensing is the primary task in numerous disciplines including industrial robotics, prosthetics, virtual and augmented reality appliances. In rigid electronics, rotations, displacements and vibrations are typically monitored using magnetic field sensors. Here, we will discuss the fabrication of flexible, stretchable and printable magnetoelectronic devices. The technology platform relies on high-performance magnetoresistive and Hall effect sensors deposited or printed on ultrathin polymeric foils. These skin conformal flexible and printable magnetosensitive elements enable touchless interactivity with our surroundings based on the interaction with magnetic fields, which is relevant for smart skins, soft robotics and human-machine interfaces.

The widespread adoption of gallium nitride (GaN) in radiation-hard semiconductor devices relies on a comprehensive understanding of its response to strongly ionizing radiation. Despite being widely acclaimed for its high radiation resistance, the exact effects induced by ionization are still hard to predict due to the complex phase-transition diagrams and defect creation-annihilation dynamics associated with group-III nitrides. Here, Two-Temperature Model, Molecular Dynamics simulations and Transmission Electron Microscopy, are employed to study the interaction of Swift Heavy Ions with GaN at the atomic level. The simulations reveal a high propensity of GaN to recrystallize the region melted by the impinging ion leading to high thresholds for permanent track formation. Although the effect exists in all studied electronic energy loss regimes, its efficiency is reduced with increasing electronic energy loss, in particular when there is dissociation of the material and subsequent formation of N 2 bubbles. The recrystallization is also hampered near the surface where voids and pits are prominent. The exceptional agreement between the simulated and experimental results establishes the applicability of the model to examine the entire electronic energy loss spectrum. Furthermore, the model supports an empirical relation between the interaction cross sections (namely for melting and amorphization) and the electronic energy loss.

Personnel scheduling in organizations can be disrupted by unforeseen events that require efficient planning. A recent example is the COVID-19 pandemic that disrupted global operations, compromising people's health and safety. Many organizations were forced to transition to full remote work to prevent the spread of the virus and ensure employee safety. Although working entirely remotely is effective for some organizations, others must balance workplace occupancy and infection risk to keep their operations functioning efficiently despite a global health crisis. We address this issue by developing a days-off scheduling model that captures employees' interactions through the underlying contact network. To solve the problem, we propose a Mixed Integer Linear Programming model considering a Microscopic Markov Chain Approach to determine the probability of infection in a contact network that mimics the employees' interactions. The model determines, during a given planning period, the optimal staffing mix to maximize occupancy while minimizing the risk of infection in the presence of testing protocols. We conduct sensitivity analysis to assess the approach's robustness while considering different contact networks and testing strategies. Through extensive computational analysis, we show that the degree of contact among employees is not the sole factor to consider when defining personnel scheduling policies during disease outbreaks. The decision-maker must balance the employee allocation with tailored testing interventions based on management's priorities to mitigate the effects while ensuring the desired occupancy at a lower risk.

Using a fast and accurate neural network potential, we are able to systematically
explore the energy landscape of large unit cells of bulk magnesium oxide with the
minima hopping method. The potential is trained with a focus on the near-
stoichiometric compositions, in particular on suboxides, i.e., Mg x O 1−x with 0.50 < x <
0.60. Our extensive exploration demonstrates that for bulk stoichiometric
compounds, there are several new low-energy rock-salt-like structures in which Mg
atoms are octahedrally six-coordinated and form trigonal prismatic motifs with
different stacking sequences.
Furthermore, we find a dense spectrum of novel nonstoichiometric crystal phases of
Mg x O 1−x for each composition of x. These structures are mostly similar to the rock-salt
structure with octahedral coordination and five-coordinated Mg atoms. Due to the
removal of one oxygen atom, the energy landscape becomes more glass-like with
oxygen-vacancy type structures that all lie very close to each other energetically. For
the same number of magnesium and oxygen atoms, our oxygen-deficient structures
are lower in energy if the vacancies are aligned along lines or planes than rock-salt
structures with randomly distributed oxygen vacancies. We also found the putative
global minima configurations for each composition of the nonstoichiometric suboxide
structures. These structures are predominantly composed of MgO(111) layers of the
rock-salt structure which are terminated with Mg atoms at the top and bottom and
are stacked in different sequences along the z direction. Like for other materials,
these Magnéli-type phases have properties that differ considerably from their
stoichiometric counterparts such as high electrical conductivity

Rohstoffkreisläufe schließen als wesentlicher Faktor für den Klimaschutz - wo sind die Grenzen des Recyclings? Können wir bei hoher Recyclingquote auch auf Bergbau verzichten? Unsere Herausforderungen erklärt an den Beispielen des Handys und der Elektromobilität.

As has been stated e.g. in Meisel et al. (2022) that the mineralogical composition of a certain sample
does have an influence on the analytical geochemical results obtained. Prior to the start of the analytical
geochemical studies, an approximate idea of the mineralogical composition of the sample to be
analyzed should be available. This helps to select the digestion method and the methods to be used
(matrix effect).
We chose 14 samples from different GeoPT rounds representing a wide spectrum of rock composition
for a detailed quantitative X-ray diffraction (XRD) study.
Based on the determined quantitative mineralogical composition, an estimation of the chemical
composition can be made. This is achieved by a back calculation using the mineral chemistry of the
identified mineral phases. The Profex/BGMN software package (Doebelin & Kleeberg, 2015)
automatically calculates these values. These data can be directly compared with the results of a GeoPT
round robin.
It must be taken into account that the sample preparation for a GeoPT round robin is not ideal for
quantitative XRD investigations and artifacts must be expected. XRD slightly underestimates e.g.
SiO2-values (Fig. 1). This is mainly due to an overgrinding effect, where quartz forms an
“amorphization” layer at the surface (O’Connor & Chang, 1986).

The GeoPT programme (IAG, 2020) is a valuable tool that allows geochemical laboratories to test their routine analytical performance and, if necessary, undertake remedial action where errors of inappropriate magnitude are detected. During the past 25 years and 63 rounds so far, the GeoPT programme has provided a great variety of rock samples for the benefit of participants. While the GeoPT programme solely focuses on geochemical composition data, it is well known that the mineralogical content of geochemical materials is also of importance to analysts, to researchers and to industrialists (e.g. Meisel et al. 2022). It has long been known that the so-called mineralogical effect can influence the quantitative outcomes of XRF measurements made on pressed pellets. In addition, wet chemical techniques may also suffer from incomplete digestion when resistant minerals are present, unless a rigorous multi acid attack or a combination of fusion and dissolution are employed. The mineralogical content of geological materials is, therefore, important but is not implicitly assessed in the GeoPT programme. Is there a need, therefore, for a dedicated mineralogical proficiency testing programme (MinPT?)?

To our knowledge, there is only one regular mineralogical round robin interlaboratory test programme – the biennial Reynolds Cup (Raven & Self, 2017), which focuses on clay minerals and follows a slightly different approach as the composition of the material is known to the organizers at the outset.

The reason for this interactive poster is to investigate the need for a mineralogical interlaboratory round robin test linked to the GeoPT proficiency testing programme. The idea is that essentially the same material would be distributed in a simultaneous GeoPT and mineralogical test round. Special preparation procedures will be required to ensure that the test material is suitable for both geochemical and mineralogical laboratories operating techniques such as X-ray diffraction, automated mineralogy (MLA, QUEMSCAN, TIMA, etc.) and others. Quantitative mineralogical data from this round robin test would be assessed where possible, using the same well-established GeoPT procedures and providing participating laboratories with personalized performance data. Furthermore, a direct comparison with bulk compositional data from the complementary GeoPT round would permit further insights into analytical performance. It is important to note that there is no expectation that participating laboratories would have to participate in both the GeoPT and mineralogical rounds, but participation in both would be welcomed.

With the help of this interactive poster, we would like to ask delegates for indications of their general interest in participating in a combined mineralogical/geochemical test of proficiency based on effectively the same test materials.

References:

Meisel, T. C., Webb, P. C., & Rachetti, A. (2022). Highlights from 25 Years of the Geo PT Programme: What Can be Learnt for the Advancement of Geoanalysis. Geostandards and Geoanalytical Research.
Raven, M. D., & Self, P. G. (2017). Outcomes of 12 years of the Reynolds Cup quantitative mineral analysis round robin. Clays and Clay Minerals, 65(2), 122-134.
IAG (2020). Protocol for the operation of the GeoPT Proficiency testing scheme. International Association of Geoanalysts (Keyworth, UK), 18pp. http://www.geoanalyst.org/wp-content/uploads/2020/07/GeoPT-revised-protocol-2020.pdf.

Nachhaltiger Umgang mit natürlichen Rohstoffquellen ist eine der drängendsten Aufgaben unserer Gesellschaft. Das Konzept dazu ist die sogn. Kreislaufwirtschaft. Damit verbunden sind Worte wie Nachhaltigkeit und Recycling. Doch alles was recycled wird, muss erst durch Bergbau gewonnen werden. Wo sind die Grenzen des Recyclings? Können wir bei hoher Recyclingquote auch auf Bergbau verzichten?

Jeder von uns hat ein Handy und die Anzahl der Elektroautos nimmt zu. Dazu braucht man Rohstoffe, die zuvor in diesen Mengen nicht benötigt wurden. Die Herausforderungen für die Gewinnung der Rohstoffe werden an Beispielen des Handys und der Elektromobilität erklärt.

The cabonatite-hosted Namxe rare earth element (REE) deposit in northern Vietnam has a total rare earth oxide (TREO) content of up to 2 wt% which is mainly hosted by parasite in the southern part of the deposit. Detailed mineralogical investigation of the rather complex mineralization revealed that parisite occurs in two geochemical varieties with slightly differing REE2O3/CaO ratios (5.8 ±0.2 vs. 6.8 ±0.35). Parisite occurs in dykes together with carbonates (ankerite, calcite) and barite and is often intergrown with fine-grained (sub 100µm size fraction) barite-celestine group minerals. The recognition of remnants of corroded bastnaesite suggest that REE enrichment is a result of a multi-stage process involving Sr- and CO3-rich fluids with mantle signature (δ13C values of -6.8 ‰ to -2.89 ‰) with no or little additional REE input.
We applied state-of-the-art techniques to propose a possible processing route of the ore, including experiments using sensor-sorting, selective comminution, magnetic separation (HIMS and WHIMS) and froth flotation. Sensor sorting turned out to be quite efficient as the basaltic host rock can be separated from the dyke material, resulting in a mass reduction of about 30% and a REE loss of less than 2%. Selective comminution experiments revealed similar results with the rejection of 27% of barren material and a slightly higher loss of REE (3.5%). Two step froth flotation of a model blend led to a concentrate with >40% TREO content.

The influence of non-interacting Kohn–Sham Hamiltonian on the non-self consistent GW(G0W0) quasiparticle gap and Bethe–Salpeter-equation (BSE) optical spectra of anatase TiO2 is systematically evaluated. G0W0 and BSE calculations are carried out starting with HSE06 (Heyd–Scuseria–Ernzerhof) type functionals containing 20%, 25% and 30% exact Hartree–Fock exchange. The results are also compared against G0W0 + BSE calculations starting from semi-local (PBE) functionals. Our results indicate that the G0W0 and BSE calculations of anatase TiO2 depend critically on the mean-field starting point, wherein its dependence is mainly introduced through the dielectric screening evaluated at the intermediate G0W0.We find that the band dispersion, density of states, and consequently the oscillator strengths of optical excitation and spatial localization of excitons are insensitive to the starting points while the quasiparticle gap, optical gap and exciton binding energies are strongly affected. G0W0 quasiparticle gap of anatase TiO2 computed over hybrid functional starting points is typically overestimated compared to measured values. However, by varying the amount of exact exchange, the dielectric screening can be tuned, and thus the quasiparticle gap. Exciton binding energy is shown to increase in proportion to the increase of the amount of exact exchange. A simple extrapolation of the calculated data leads to the exact match with the recently measured value with 13% of the exact exchange. Systematic analysis of G0W0 + BSE calculation starting from screened hybrid functionals provided in this study forms a reference for all such future calculations of pristine anatase TiO2 and its derivatives.

Open-shell systems are normally described using spin density
functional theory (SDFT) rather than regular DFT, due to spinpolarised approximations appearing to yield superior results
for exchange-correlation (xc) energies. To address the seemingly poorer (xc) energies obtained via DFT approximations
(DFAs), we show that correcting for a qualitative error in the
DFT description for open-shell systems, one obtains results
with SDFT accuracy. Furthermore, in the absence of external magnetic fields, both DFT and SDFT should reduce to
the same limit. We provide the link between these two theories, demonstrating how the regular KS equations of SDFT
reduce to a new (generalised) set of KS equations for DFT in
this limit. We also extend these ideas to ensembles of varying
electron number, obtaining a finite derivative discontinuity for
commonly used (semi-)local DFAs.

Molecular diffusion is an important transport mechanism for radionuclide migration in low-permeable argillaceous host rock such as Opalinus Clay (OPA). In this study, the influence of sedimentary and diagenetic heterogeneity on heterogeneous diffusion in sandy facies of OPA (SF-OPA) from lamina scale to drill core scale is investigated using an upscaling workflow to model diffusive transport from the pore scale to the core scale. Our numerical results based on the simplified structural model show fast diffusion fronts in clay laminae (7 mm displacement after 6 days of diffusion) and slow diffusion fronts in carbonate lenses and sand laminae (4 mm displacement after 6 days of diffusion), demonstrating the endmembers of heterogeneous diffusion patterns in SF-OPA. Moreover, our results show that the diffusion fronts begin to homogenize after 22 days of diffusion with the specific influence of carbonate lenses (here: length = 1 cm, thickness = 3 mm). This example illustrates how material heterogeneities affect heterogeneous diffusion on a small temporal and spatial scale. The sensitivity studies show that the diffusion length and homogenization time increase by up to 190% when the length and thickness of the carbonate lenses are doubled. Using four compositional endmembers, we show the generalized diffusion behavior to demonstrate the influence of thin laminae and thick layers as well as dispersed small and large diagenetic concretions on the homogeneity of diffusion. These results demonstrate that the geometry of sedimentary and diagenetic material and the subfacies composition are the controlling factors for quantifying diffusion length and homogenization time. This study provides quantitative constraints on the temporal and spatial evolution of heterogeneous diffusion at the core scale. This quantitatively improves the predictability of radionuclide migration in host rocks as a function of compositional and pore network-specific parameters.

The study of warm dense matter (WDM) is critical to our understanding of many interesting scientific and technological phenomena, in particular various astrophysical applications, and inertial confinement fusion. To develop accurate models for WDM, one has to account for the quantum behaviour of electrons (and sometimes nuclei too) across a wide range of temperatures and densities, which presents a challenge for established modelling techniques. In our poster, we introduce the concept of an average-atom model, which accounts (partially) for these quantum interactions in a computationally efficient way. We show some example applications of average-atom models, to demonstrate their usefulness in the WDM regime. We also present atoMEC: an average-atom code for matter under extreme conditions, which is open-source and written in Python.

Average-atom models are an essential tool in modelling the warm dense matter regime, because they can be used to compute key quantities, such as equation-of-state data, for a fraction of the computational cost of higher-fidelity simulations such as DFT-MD. However, a variety of different models exist, and it is important to benchmark these models to understand their limitations and expected accuracy under various conditions. In this presentation, we focus on two key properties in WDM — the mean ionization state and pressure — for a range of materials, densities and temperatures. Through comparison with higher-fidelity simulations and experimental results, we probe the accuracy of an average-atom model, considering various choices of approximation within that model. We demonstrate a well-chosen average-atom model, under the right conditions, can yield close agreement with these benchmarks.

Modelling the behaviour of materials under warm dense matter (WDM) conditions is important to our understanding of various astrophysical phenomena and inertial confinement fusion (for example). Finite-temperature Kohn--Sham density-functional theory (KS-DFT) can be applied to study materials exposed to WDM conditions --- temperatures of around 1-1000 eV and densities from 10^-2 to 10^4 g/cm3 --- but the usual KS-DFT approach for periodic systems becomes computationally intractable at higher temperatures. In this presentation, we first derive a density-functional average-atom model --- which reduces the full many-body system of electrons and nuclei to a single atom immersed in a plasma --- from first principles. Using this model, we investigate the behaviour of the mean ionization state and pressure (key properties in WDM) for a range of materials, densities and temperatures. Through comparison with higher fidelity simulations and experimental results, we demonstrate that computationally light average-atom models yield accurate results under the right conditions and approximations.

Warm dense matter (WDM) is an exotic phase of matter which lies at the intersection between the condensed-matter and plasma physics communities. Understanding the behaviour of materials under WDM conditions is important for nuclear fusion research, and astro and planetary physics. Average-atom models are widely-used in WDM research, but the large number of models available and lack of open-source availability makes them hard to understand and use. In this talk, we first derive an average-atom model from first principles, then introduce our Python library atoMEC, which aims to facilitate development and comparison of average-atom models.

Average-atom models are an important tool in studying matter under extreme conditions, such as those conditions experienced in planetary cores, brown and white dwarfs, and during inertial confinement fusion. In the right context, average-atom models can yield results with similar accuracy to simulations which require orders of magnitude more computing time, and thus can greatly reduce financial and environmental costs. Unfortunately, due to the wide range of possible models and approximations, and the lack of open-source codes, average-atom models can at times appear inaccessible. In this paper, we present our open-source average-atom code, atoMEC. We explain the aims and structure of atoMEC to illuminate the different stages and options in an average-atom calculation, and to facilitate community contributions. We also discuss the use of various open-source Python packages in atoMEC, which have expedited its development.

Understanding the electronic transport properties of iron under high temperatures and pressures is essential for constraining geophysical processes. The difficulty of reliably measuring these properties under Earth-core conditions calls for sophisticated theoretical methods that can support diagnostics. We compute the results of the electrical conductivity within the pressure and temperature ranges found in Earth’s core by simulating microscopic Ohm’s law using time-dependent density functional theory (TDDFT).
We are working on Spectral Neighbor Analysis Potential (SNAP) machine-learning potential for large-scale molecular dynamics simulations including coupling spin-lattice dynamics. The generated models can be used to simulate phenomena in iron, such as the interplay of phonon, and magnetic contributions to the thermal conductivity, or to perform high-pressure shock compression simulations.

Background. Glioblastoma (GBM) is a fast-growing primary brain tumor characterized by high
invasiveness and resistance. This results in poor patient survival. Resistance is caused by
many factors, including cell-extracellular matrix (ECM) interactions. Here, we addressed the
role of adhesion protein integrin α2, which we identified in a high-throughput screen for novel
potential targets in GBM cells treated with standard therapy consisting of temozolomide (TMZ)
and radiation.
Methods. In our study, we used a range of primary/stem-like and established GBM cell models
in vitro and in vivo. To identify regulatory mechanisms, we employed high-throughput kinome
profiling, Western blotting, immunofluorescence staining, reporter and activity assays.
Results. Our data showed that integrin α2 is overexpressed in GBM compared to normal brain
and, that its deletion causes radiochemosensitization. Similarly, invasion and adhesion were
significantly reduced in TMZ-irradiated GBM cell models. Furthermore, we found that integrin
α2-knockdown impairs proliferation of GBM cells without affecting DNA damage repair. At the
mechanistic level, we found that integrin α2 affects the activity of activating transcription factor
1 (ATF1) and modulates the expression of extracellular signal-regulated kinase 1 (ERK1)
regulated by extracellular signals. Finally, we demonstrated that integrin α2-deficiency inhibits
tumor growth and thereby prolongs survival of mice with orthotopically growing GBM
xenografts.
Conclusions. Taken together our data suggest that integrin α2 may be a promising target to
overcome GBM resistance to radio- and chemotherapy. Thus, it would be worth evaluating
how efficient and safe the adjuvant use of integrin α2 inhibitors is to standard
radio(chemo)therapy in GBM.

Several properties of hydrogen in the solid, liquid, and metallic liquid are investigated for different xc functionals

Polymethylmethacrylate (PMMA) removal during septic total joint arthroplasty revisionis associated with a high fracture and perforation risk. Ultrasonic cement removal isconsidered a bone‐preserving technique. Currently, there is still a lack of sound data onefficacy as it is difficult to detect smaller residues with reasonable technical effort.However, incomplete removal is associated with the risk of biofilm coverage of theresidue. Therefore, the study aimed to investigate the efficiency of ultrasonic‐basedPMMA removal in a human cadaver model. The femoral components of a total hip and atotal knee prosthesis were implanted in two cadaver femoral canals by 3rd generationcement fixation technique. Implants were then removed. Cement mantle extraction wasperformed with the OSCAR‐3‐System ultrasonic system (Orthofix®). Quantitativeanalysis of cement residues was carried out with dual‐energy and microcomputertomography. With a 20 μm resolution, in vitro microcomputer tomography visualized tiniest PMMA residues. For clinical use, dual‐energy computer tomography tissuedecomposition with 0.75 mm resolution is suitable. With ultrasound, more than 99% ofPMMA was removed. Seven hundred thirty‐four residues with a mean volume of0.40 ± 4.95 mm3were identified with only 4 exceeding 1 cm in length in at least oneaxis. Ultrasonic cement removal of PMMA was almost complete and can therefore beconsidered a highly effective technique.For the first time, PMMA residues in thesub‐millimetre range were detected by computer tomography. Clinical implications ofthe small remaining PMMA fraction on the eradication rate of periprosthetic jointinfection warrants further investigations.

Ultrathin asymmetrically sandwiched ferromagnetic films support fast moving chiral magnetic domain walls and skyrmions [1,2]. This paves the way to the realization of prospective racetrack memory concept, the performance of which is determined by the static and dynamic micromagnetic parameters [3]. The necessity of having strong Dzyaloshinskii-Moriya interactions (DMI) and perpendicular magnetic anisotropy requires the utilization of ultrathin magnetic (~1 nm) layers, which compromized structural quality, that substantially enhances the magnetic damping for non-collinear magnetic textures.

Here, we present the experimental and theoretical analysis of ultrathin Co films with asymmetric interfaces //CrO x /Co/Pt and estimation of their micromagnetic parameters based on the analysis of the temperature dependence of magnetization as well as imaging of the morphology of magnetic domain walls (DWs) in stripes. Namely, we show that the best fit to the magnetometry data up to room temperature is obtained within a quasi-2D model, accounting for the lowest transversal magnons [4]. The fit provides access to the exchange constant in asymmetric stackes which is found to be about 1 order of magnitude smaller compared to the bulk Co. The experimentally observed tilt of magnetic domain walls in stripes in statics can be explained based on two models: (I) A unidirectional tilt could appear in equilibrium as a result of the competition between the DMI and additional in-plane easy-axis anisotropy, which breaks the symmetry of the magnetic texture and introduce tilts [5]. (II) A static DW tilt could appear due to the spatial variation of magnetic parameters, which introduce pinning centers for moving tilted DWs driven by magnetic field and can fix them at remanence [6]. We found that the second model is in line with the experimental observations and allows to determine self-consistently the DW damping parameter and DMI constant for the particular layer stack. The DW damping is found to be about 0.1 and explained by the enhanced longitudinal relaxation mechanism. The latter is shown to much stronger tan the standard transversal relaxation and can be even stronger than the spin pumping contribution for the case of ultrathin ferromagnetic films [7].

References:

[1] N. Nagaosa and Y. Tokura, “Topological properties and dynamics of magnetic skyrmions”, Nat. Nanotechnol. 8, 899 (2013).
[2] A. Fert, N. Reyren, and V. Cros, “Magnetic skyrmions: advances in physics and potential applications”, Nat. Rev. Mater. 2, 17031 (2017).
[3] C. Garg, S.-H. Yang, T. Phung, A. Pushp and S. S. P. Parkin, “Dramatic influence of curvature of nanowire on chiral domain wall velocity”, Sci. Adv. 3, e1602804 (2017).
[4] I. A. Yastremsky, O. M. Volkov, M. Kopte, T. Kosub, S. Stienen, K. Lenz, J. Lindner, J. Fassbender, B. A. Ivanov and D. Makarov, “Thermodynamics and Exchange Sti ff ness of Asymmetrically Sandwiched Ultrathin Ferromagnetic Films with Perpendicular Anisotropy”, Phys. Rev. Appl. 12, 064038 (2019).
[5] O. V. Pylypovskyi, V. P. Kravchuk, O. M. Volkov, J. Fassbender, D. D. Sheka and D. Makarov, “Unidirectional tilt of domain walls in equilibrium in biaxial stripes with Dzyaloshinskii–Moriya interaction”, J. Phys. D: Appl. Phys. 53, 395003 (2020).
[6] O. M. Volkov, F. Kronast, C. Abert, E. Se. Oliveros Mata, T. Kosub, P. Makushko, D. Erb, O. V. Pylypovskyi, M.-A. Mawass, D. Sheka, S. Zhou, J. Fassbender and D. Makarov, “Domain-Wall Damping in Ultrathin Nanostripes with Dzyaloshinskii-Moriya Interaction”, Phys. Rev. Appl. 15, 034038 (2021).
[7] I. A. Yastremsky, J. Fassbender, B. A. Ivanov, and D. Makarov, “Enhanced Longitudinal Relaxation of Magnetic Solitons in Ultrathin Films”, Phys. Rev. Appl. 17, L061002 (2022).

The interplay between geometry and topology of the order parameter is crucial properties in soft and condensed matter physics, including cell membranes [1], nematic crystals [2,3], superfluids [4], semiconductors [5], ferromagnets [6] and superconductors [7]. Until recently, in the case of magentism, the influence of the geometry on the magnetization vector fields was addressed primarily by the design of the sample boundaries, aiming to tailor anisotropy of the samples. With the development of novel fabrication techniques allowing to realize complex 3D architectures, not only boundary effects, but also local curvatures can be addressed rigorously for the case of ferromagnets and antiferromagnets. It is shown that curvature governs the appearance of geometry-induced chiral and anisotropic responses [6-8].

Here we provide experimental confirmations of the existence of local and non-local curvature-induced chiral interactions of the exchange and magnetostatic origin in conventional soft ferromagnetic materials. Namely, we will present the experimental validation of the appearance of exchange-driven Dzyaloshinskii-Moriya interaction interaction (DMI, local effect) for the case of conventional achiral yet geometrically curved magnetic materials [9,10]. This curvature induced DMI is predicted to stabilize skyrmions [11] and skyrmionium states [12]. Furthermore, we will address the impact of nonlocal magnetostatic interaction on the properties of curvilinear ferromagnets, which enables the stabilization of topological magnetic textures [13,14], realization of high-speed magnetic racetracks [15] and curvature-induced asymmetric spin-wave dispersions in nanotubes [16]. Furthermore, symmetry analysis demonstrates the possibility to generate a fundamentally new chiral symmetry breaking effect, which is essentially nonlocal [13]. Thus, geometric curvature of thin films and nanowires is envisioned as a toolbox to create artificial chiral nanostructures from achiral magnetic materials.

References:

[1] H. T. McMahon and J. L. Gallop “Membrane curvature and mechanisms of dynamic cell membrane remodelling”, Nature 438, 590 (2005).
[2] T. Lopez-Leon, V. Koning, K. B. S. Devaiah, V. Vitelli and A. Fernandez-Nieves, “Frustrated nematic order in spherical geometries”, Nature Physics 7, 391 (2011).
[3] G. Napoli, O. V. Pylypovskyi, D. D. Sheka and L. Vergori, “Nematic shells: new insights in topology- and curvature-induced e ff ects”, Soft Matter 17, 10322-10333 (2021).
[4] H. Kuratsuji, “Stochastic theory of quantum vortex on a sphere”, Phys. Rev. E 85, 031150 (2012).
[5] C. Ortix, Phys, “Quantum mechanics of a spin-orbit coupled electron constrained to a space curve”, Phys. Rev. B 91, 245412 (2015).
[6] D. D. Sheka, O. V. Pylypovskyi, O. M. Volkov, K. V. Yershov, V. P. Kravchuk and D. Makarov, “Fundamentals of Curvilinear Ferromagnetism: Statics and Dynamics of Geometrically Curved Wires and Narrow Ribbons”, Small 18, 2105219 (2022).
[7] D. Makarov, O. M. Volkov, A. Kakay, O. V. Pylypovskyi, B. Budinská and O. V. Dobrovolskiy, “New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures”, Adv. Mater. 34, 2101758 (2022).
[8] Y. Gaididei, V. P. Kravchuk and D. D. Sheka, “Curvature Effects in Thin Magnetic Shells”, Phys. Rev. Lett. 112, 257203 (2014).
[9] O. M. Volkov, D. D. Sheka, Y. Gaididei, V. P. Kravchuk, U. K. Rößler, J. Fassbender and D. Makarov, ”Mesoscale Dzyaloshinskii-Moriya interaction: geometrical tailoring of the magnetochirality”, Sci. Rep. 8, 866 (2018).
[10] O. M. Volkov, A. Kákay, F. Kronast, I. Mönch, M.-A. Mawass, J. Fassbender and D. Makarov, “Experimental observation of exchange-driven chiral effects in curvilinear magnetism”, Phys. Rev. Lett. 123, 077201 (2019).
[11] V. P. Kravchuk, D. D. Sheka, A. Kákay, O. M. Volkov, U. K. Rößler, J. van den Brink, D. Makarov and Y. Gaididei, “Multiplet of Skyrmion States on a Curvilinear Defect: Reconfigurable Skyrmion Lattices”, Phys. Rev. Lett. 120, 067201 (2018).
[12] O. V. Pylypovskyi, D. Makarov, V. P. Kravchuk, Y. Gaididei, A. Saxena and D. D. Sheka, “Chiral Skyrmion and Skyrmionium States Engineered by the Gradient of Curvature”, Phys. Rev. Appl. 10, 064057 (2018).
[13] D. D. Sheka, O. V. Pylypovskyi, P. Landeros, Y. Gaididei, A. Kákay and D. Makarov, “Nonlocal chiral symmetry breaking in curvilinear magnetic shells”, Commun. Phys. 3, 128 (2020).
[14] C. Donnelly, A. Hierro-Rodrı́guez, C. Abert, K. Witte, L. Skoric, D. Sanz-Hernández, S. Finizio, F. Meng, S. McVitie, J. Raabe, D. Suess, R. Cowburn and A. Fernández-Pacheco, “Complex free-space magnetic field textures induced by three-dimensional magnetic nanostructures”, Nat. Nanotech. 17, 136–142 (2022).
[15] M. Yan, A. Kákay, S. Gliga and R. Hertel, “Beating the Walker limit with massless domain walls in cylindrical nanowires”, Phys. Rev. Lett. 104, 057201 (2010).
[16] J. A. Otálora, M. Yan, H. Schultheiss, R. Hertel and A. Kákay, “Curvature-induced asymmetric spin-wave dispersion”, Phys. Rev. Lett. 117, 227203 (2016).

A new method to measure and quantify the 3D mineralogical composition of particulate
materials using X-ray computed micro-tomography (CT) is presented. The new method is
part of a workflow designed to standardize the analysis of particles based on their
microstructures without the need to segment the individual classes or grains. Classification
follows a decision tree with criteria derived from particle histogram parameters that are
specific to each microstructure, which in turn can be identified by 2D-based automated
quantitative mineralogy. The quantification of mineral abundances is implemented at the
particle level according to the complexity of the particle by taking into consideration the
partial volume effect at interphases. The new method was tested on two samples with
different particle size distributions from a carbonate rock containing various microstructures
and phases. The method allowed differentiation and quantification of more mineral classes
than traditional 3D image segmentation that uses only the grey-scale for mineral classification.
Nevertheless, due to lower spatial resolution and lack of chemical information, not all
phases identified in 2D could be distinguished. However, quantification of the mineral
classes that could be distinguished was more representative than their 2D quantification,
especially for coarser particle sizes and for minor phases. Therefore, the new 3D method
shows great potential as a complement to 2D-based methods and as an alternative to traditional
phase segmentation analysis of 3D images. Particle-based quantification of mineralogical
and 3D geometrical properties of particles opens new applications in the raw
materials and particle processing industries.

River basins across the world are shaped by local land topography and generally have a dendritic structure formed by convergence of river streams originating in a watershed until they end up in the main river. These river basins are also home to a plethora of aquatic lifeforms. Movement patterns of riverine biodiversity, especially fishes, are shaped by dendritic structure of river networks (see Figure 1) and habitat capacity of river basins. The ongoing river networks project at CASUS is specifically aimed at developing models to study the effects of dendritic network topology on fish biodiversity and thereby be able to predict biodiversity patterns across various river basins. Starting with an initial distribution of fish species on the river network, we explore how the biodiversity patterns, such as local species richness (LSR), in dendritic river networks evolve with time, under the assumption of species being equivalent on a per capita basis. Such neutral biodiversity models have been able to successfully explain a suite of biodiversity indices of plant and animal species across various ecological systems. In summary, the river project aims to bring together the neutral biodiversity theory and the framework of dispersal over networks to make predictions on biodiversity in riverine systems across the world. This would enable understanding the factors shaping present biodiversity and allow us to explore how climate change might affect future riverine biodiversity.

The centenary of the birth of H. Gobind Khorana provides an auspicious opportunity to review the origins and evolution of parallel advances in biophysical methodology and molecular genetics technology used to study membrane proteins. Interdisciplinary work in the Khorana laboratory in the late 1970s and for the next three decades led to productive collaborations and fostered three subsequent scientific generations whose biophysical work on membrane proteins has led to detailed elucidation of the molecular mechanisms of energy transduction by the light-driven proton pump bacteriorhodopsin (bR) and signal transduction by the G protein–coupled receptor (GPCR) rhodopsin. This review will highlight the origins and advances of biophysical studies of membrane proteins made possible by the application of molecular genetics approaches to engineer site-specific alterations of membrane protein structures.

Dynamics of two types of chiral magnetic domain walls in magnetic cylindrical nanowires under spin-polarised current are investigated by means of micromagnetic simulations. We show that Bloch point domain wall with chirality identical to that of the Oersted field can propagate without dynamical instabilities with velocities ca. 300 m/s. Domain wall width is shown to widen for a larger current density which limits the velocity increase. For domain walls with opposite chirality, we observed a new pinning mechanism created by the action of the Oersted field and limiting their propagation distance even after chirality switching. Vortex-antivortex domain walls transform into Bloch point domain wall, after which they can unexpectedly propagate either along or against the current direction. Our results demonstrate that domain wall dynamics under current in cylindrical magnetic nanowires can result in a plethora of different behaviors which will have important implications for future 3D spintronic devices.

U₃Cu₄Ge₄ is a uniaxial ferromagnet that displays a first-order magnetization process (FOMP) at 25 T for field applied along the hard b axis. Here, we report on ultrasound and magnetostriction measurements of U₃Cu₄Ge₄ in static and pulsed magnetic fields up to 40 T. The FOMP causes stepwise anomalies in the magnetoelastic properties. U₃Cu₄Ge₄ elongates along the a and c axes and shrinks along the b axis, leading to an almost zero volume effect. The sound velocities of the longitudinal and transverse acoustic waves decrease sharply at the FOMP, whereas the sound attenuation shows pronounced peaks. An analysis of the ultrasound data using a mean-field theory suggests the existence of quadrupolar interactions and crystal-electric-field effects. The 5 f electronic states are between itinerant and localized, typical of uranium-based intermetallic compounds.

This document is the first version of the Data Management Plan (DMP) of the project ”advanced Muon Campus in US and Europe contribution” (aMUSE), funded by the European Union under the call ”H2020-MSCA-RISE-2020” (Research and Innovation Staff Exchange) with Grant Agreement number 101006726.

The aMUSE project coordinates the activities of about 80 researchers from twelve European research institutes and industries participating to the search for New Physics in the muon sector and to the design of new generation muon accelerators in high-profile US laboratories (Fermilab, BNL, SLAC). The project involves the two Fermilab Muon Campus Experiments:

• Muon (g-2), aiming to shed light on the discrepancy on the anomalous magnetic momentum of the muon;

• Mu2e, whose goal is to improve by four order of magnitudes the discover sensitivity for the not yet observed conversion of a muon to an electron.

aMUSE proposes also an ambitious extension of the activities already foreseen for the Muon Campus: an RD program for innovative detectors for the Mu2e upgrade (Mu2e-II, with 10 times larger beam intensity) and the design of a new beamline for CLFV searches based on muon decays as an alternative to Mu2e-II. aMUSE also constitutes a launch pad for a European-USA network for the development of muon beams for low (CLFV) and high (muon collider) energy frontiers.

During the duration of the aMUSE project (from 1.1.2022 to 31.12.2025), this first version of the Data Management Plan will be regularly evaluated and eventually adjusted to suit the needs of the aMUSE project.

This document was submitted as deliverable D7.8 in Work Package 7.

The fundamental laws necessary for the mathematical treatment of a large part of physics and the whole of chemistry are thus completely known, and the difficulty lies only in the fact that application of these laws leads to equations that are too complex to be solved." Nearly a century has passed, yet the famous quote by Paul Dirac still gets to the heart of many research fields within theoretical physics, quantum chemistry, material science, etc. In this talk, I will show how we can use cutting-edge numerical methods on modern high-performance computing systems to effectively overcome these limitations in many cases. In this way, we get unprecedented insights into quantum many-body systems on the nanoscale going all the way from ultracold atoms like superfluid helium to warm dense matter that occurs within planetary interiors and thermonuclear fusion applications.

Radiation sources with a stable carrier-envelope phase (CEP) are highly demanded tools for field-resolved studies of light-matter interaction, providing access both to the amplitude and phase information of dynamical processes. At the same time, many coherent light sources, including those with outstanding power and spectral characteristics lack CEP stability, and so far could not be used for this type of research. In this work, we present a method enabling linear and non-linear phase-resolved terahertz (THz) -pump laser-probe experiments with CEP-unstable THz sources. THz CEP information for each pulse is extracted using a specially designed electro-optical detection scheme. The method correlates the extracted CEP value for each pulse with the THz-induced response in the parallel pump-probe experiment to obtain an absolute phase-resolved response after proper sorting and averaging. As a proof-of-concept, we demonstrate experimentally field-resolved THz time-domain spectroscopy with sub-cycle temporal resolution using the pulsed radiation of a CEP-unstable infrared free-electron laser (IR-FEL) operating at 13 MHz repetition rate. In spite of the long history of IR-FELs and their unique operational characteristics, no successful realization of CEP-stable operation has been demonstrated yet. Being CEP-unstable, IR-FEL radiation has so far only been used in non-coherent measurements without phase resolution. The technique demonstrated here is robust, operates easily at high-repetition rates and for short THz pulses, and enables common sequential field-resolved time-domain experiments. The implementation of such a technique at IR-FEL user end-stations will facilitate a new class of linear and non-linear experiments for studying coherent light-driven phenomena with increased signal-to-noise ratio.

Schon früh wurde am Helmholtz-Zentrum Dresden – Rossendorf (HZDR) die Relevanz eines nachhaltigen Umgangs mit Forschungsdaten und -Software gemäß FAIR-Prinzipen erkannt. Vor diesem Hintergrund wurden seit 2017 schrittweise neue (Forschungs-)Infrastrukturen wie das Invenio-basierte Forschungsdatenrepositorium RODARE geschaffen, Tools wie der Research Data Management Organizer (RDMO) adaptiert und am Zentrum implementiert sowie Data und Software-Policies vereinbart.

Seither stellen sich die Interessengruppen und Akteure den generellen Herausforderungen des Forschungsdatenmanagements (FDM) wie den multidisziplinären Anforderungen, den mehrstufigen Prozessen oder der nachgelagerten Betrachtung in Projektverläufen vor allem der spezifischen Situation am HZDR. Eigenständigkeit und Kooperation unter den einzelnen Instituten gehen am Zentrum Hand in Hand. Die daraus entstehende umfangreiche Bandbreite an wissenschaftlichen Themen hat zur Folge, das immer wieder sehr spezifische Anforderungen an das FDM herangetragen werden, welche großen Einfluss auf die konkrete Ausgestaltung der Lösungsansätze haben.

Das HZDR hat die überragende Bedeutung des Wissenstransfers im FDM erkannt und zur agilen Begegnung der genannten Herausforderungen konzeptionell wichtige Weichenstellungen vorgenommen. Das FDM-Team der Bibliothek und der Abteilung „Computational Science“ bündelt die Aktivitäten aller weiteren wichtigen Akteure (u. a. „Programmplanung und Internationale Projekte“, IT-Infrastruktur, Technologie-Transfer und Rechtsabteilung) rund um das Thema. Durch gemeinsame Entwicklungen entstehen Maßnahmen, welche den Anforderungen (Metadaten, Transfer, Dokumentation, Guidelines etc.) durch das aufeinander abgestimmte Zusammenspiel von technischen Werkzeugen (Weiterentwicklung RODARE, Integration FIS und RODARE, HZDR-Cloud, Projekt Dashboard HELIPORT, Automatisierte Software Publikation über HERMES, GitLab, Dokumentation im HZDR-internen MediaWiki etc.) und Serviceleistungen (Schulungen, Workshops, Beratungen) gerecht werden sollen.

Um die offerierten Tools und Services noch besser bekannt zu machen und an den einzelnen Punkten des Forschungs-/Publikationszyklus zu implementieren, werden das HZDR-Intranet als wichtige Plattform des Wissenstransfers für die einzelnen Wertschöpfungsprozesse entlang des Datenlebenszyklus neu konzipiert und übersichtliche sowie leicht handhabbare Möglichkeiten für den Direktkontakt zwischen Wissenschaft und Dienstleister geschaffen. Der dabei gewählte ganzheitliche Ansatz soll dabei helfen, alle Facetten von Open Science nachhaltig gestalten und zukünftigen Anforderungen aktiv begegnen zu können.

Das Poster will das Konzept vorstellen, zum konstruktiven Austausch einladen sowie als Inspirationsquelle für konsequente Weiterentwicklungen im FDM dienen.

Broken magnetic symmetry is a key aspect in condensed matter physics and in particular in magnetism. It results in the appearance of chiral effects, e.g. topological Hall effect [1] and non-collinear magnetic textures including chiral domain walls and skyrmions [2,3]. These magnetochiral effects originate from an antisymmetric exchange interaction, the intrinsic Dzaloshinskii-Moriya interaction (DMI). At present, tailoring of DMI is done rather conventionally by optimizing materials, either doping a bulk single crystal or adjusting interface properties of thin films and multilayers.
A viable alternative to the conventional material screening approach can be the exploration of the interplay between geometry and topology. In the emergent field of curvilinear magnetism chiral effects are associated to the geometrically broken inversion symmetries [4]. Those appear in curvilinear architectures of even conventional materials. There are numerous exciting theoretical predictions of exchange- and magnetostatically-driven curvature effects, which do not rely on any specific modification of the intrinsic magnetic properties, but allow to create non-collinear magnetic textures in a controlled manner by tailoring local curvatures and shapes [5,6]. Until now the predicted chiral effects due to curvatures remained a neat theoretical abstraction.
Here, I present the very first experimental confirmation of the existence of the curvature-induced chiral interaction with exchange origin in a conventional soft ferromagnetic material [7,8]. It is experimentally explored the theoretical predictions, that the magnetisation reversal of flat parabolic stripes shows a two step process. By measuring the domain wall depinning field, we established that it is linked to the exchange-induced DMI and scales with curvature, that is in line with the theoretical prediction. Furthermore, the exchange-induced DMI strength can be tuned by changing the local curvature at the apex of parabola.

[1] N. Nagaosa, et al., Nature Nanotech. 8, 899 (2013).
[2] U. K. Rößler, et al., Nature 442, 797 (2006).
[3] A. Fert, et al., Nature Rev. Mat. 2, 17031 (2017).
[4] Y. Gaididei, et al., Phys. Rev. Lett. 112, 257203 (2014).
[5] J. A. Otálora, et al., Phys. Rev. Lett. 117, 227203 (2016).
[6] V. P. Kravchuk, et al., Phys. Rev. Lett. 120, 067201 (2018).
[7] O. M. Volkov et al., Phys. Rev. Lett. 123, 077201 (2019).
[8] O. M. Volkov et al., Physica Status Solidi – Rapid Research Lett. 13, 1800309 (2019).

Bubble column reactors are extensively used in a variety of industrial processes involving gas-liquid mass transfer along with chemical reactions. Despite intensive research, knowledge on the mass transfer is still limited in comparison with that on the fluid dynamics, which provides an open field of research.

In this study, mass transfer of CO2 between air bubbles and water in a bubble column is investigated using Euler-Euler simulations in OpenFOAM. Previously validated fluid dynamics models are applied and focus is put on the description of the mass transfer. Experimental data to validate the results are taken from the study of Deckwer providing axial profiles of gas fraction, and carbon dioxide concentration in both phases. Previous work considering only cases with co-current absorption is extended to also include the cases with counter-current flow and desorption. Some simplifications are made in accordance with the previous work, i.e. taking the bubble diameter to be constant and using the experimentally determined values for the mass transfer coefficient. Despite these simplifications, the simulation results show a quite good agreement with the experimental data.

As a second step, the change in bubble size due to the mass transfer is included in the simulations by means of a population balance equation discretized using the class method. The well-known model of Brauer is implemented as an example of a bubble size dependent mass transfer coefficient. Since experimental data including the development of bubble size are not available for comparison, an initial validation is provided by comparison of the polydisperse calculation with two monodisperse calculations corresponding to initial and final size in the former.

Bubble columns and bubble column reactors are well established in the field of chemical and biochemical engineering. As the flow in such apparatus influence the performance of mixing or heat and mass transfer processes, numerous studies focus on the hydrodynamic description of the flow as well as the spatial distribution of bubbles inside the vessel. For the latter, the shear-induced lift force plays a key role as it acts lateral to the bubble rise direction and correspondingly affects the lateral distribution of bubbles. However, studies regarding the lift force usually focus on rather clean or uncontaminated systems, although even small amounts of surfactants are known to significantly change bubble characteristics like drag, coalescence and breakup behavior as well as the bubble shape in the case of ellipsoidal bubbles.
In previous studies we investigated the influence of surfactants on the lift force of ellipsoidal single bubbles and could reveal strong changes of the lift coefficient 𝐶 𝐿 in comparison to clean bubbles 1 . To elaborate the effect of the lift force in buoyancy driven bubbly flows, we present measurements conducted in a 2.0 m tall column with a polydisperse bubble size. This allows to study the development of bubble size-dependent gas fraction profiles along a distance that is sufficient for the effect of the lift force to unfold sufficiently. In these experiments, we added different dozes of 1-Pentanol to the flow in order to investigate a surfactant-related modification of the lift force in dependence on the contamination degree. We use shadowgraphic high-speed imaging to determine liquid velocity and gas phase properties. For the former we use a PIV-like technique called Particle Shadow Velocimetry, while for the latter we use a novel deep learning based procedure that uses Convolutional Neural Networks to
determine bubbles and reconstruct occluded bubble parts in the images. Although the addition of surfactants affects bubbles in multiple aspects, we link some of the findings to our previous studies on the shear-induced lift force and demonstrate the influence of surfactants on several flow characteristics in bubble columns.

This thesis focuses on the image processing methods for brain perfusion measurement using a magnetic resonance imaging (MRI) sequence called arterial spin labeling (ASL). We show the importance of dealing with brain volume changes as a measurement confounder, we propose a framework for integrating all processing steps in a robust processing pipeline, and lastly, we show an application of the ASL acquisition and processing to adverse effect measurements in healthy brain tissue of patients undergoing brain radio-chemotherapy demonstrating the usefulness of the method in uncovering structural and physiological changes in the brain.

The experimental investigation of matter under extreme densities and temperatures as they occur for example in astrophysical objects and nuclear fusion applications constitutes one of the most active frontiers at the interface of material science, plasma physics, and engineering. The central obstacle is given by the rigorous interpretation of the experimental results, as even the diagnosis of basic parameters like the temperature T is rendered highly difficult by the extreme conditions. In this work, we present a simple, approximation-free method to extract the temperature of arbitrarily complex materials from scattering experiments, without the need for any simulations or an explicit deconvolution. This new paradigm can be readily implemented at modern facilities and corresponding experiments will have a profound impact on our understanding of warm dense matter and beyond, and open up a gamut of appealing possibilities in the context of thermonuclear fusion, laboratory astrophysics, and related disciplines.

Iron and iron oxide nanostructures are of broad interest for numerous applications, such as in the fields of magnetic data
storage, spintronics, biosensing and catalysis. In all of these cases, defined deposition on nanometer scale is essential for
functionality. For conventional electrodeposition of transition metals, precise thickness control and layer stability at the
nanoscale are difficult due to dissolution tendencies in acidic electrolytes after the voltage is switched off. In contrast to
previous studies that focused on self-termination of Ni and Ni-based alloys, we investigate the thickness control of nanoscale
iron oxide/iron layers using self-terminated electrodeposition from sulfate electrolytes. Electrochemical quartz crystal
microbalance measurements show that self-terminated thickness can be controlled by both deposition potential and iron ion
concentration. Comparison of experimental results with model calculations based on diffusion theory reveal two different
growth modes for self-termination. At low iron ion concentration, self-termination of iron proceeds via the formation of an
ultrathin iron hydroxide layer. At larger iron ion concentration, precipitation of bulk Fe(OH)2 dominates the film growth and
self-termination is shifted to more negative potentials. All self-terminated layers exhibit enhanced stability in the electrolyte
after the voltage is switched off compared to those deposited in the conventional deposition regime. With in situ Rutherford
backscattering spectrometry measurements, we can follow the self-terminating deposition and the stability after voltage
switch-off for longer times online. Surface analytical and morphological analyses show that the self-terminated layers exhibit
a higher iron oxide/iron ratio and are smoother than layers obtained by conventional electrodeposition.

This repository contains scripts to reproduce the results of the publication
"Electronic Structure Machine Learning Surrogates without Training". Training data has to be downloaded separately.

We compare the ion-induced electron emission from freestanding monolayers of graphene and MoS2 to find a sixfold higher number of emitted electrons for graphene even though both materials have similar work functions. An effective single-band Hubbard model explains this finding by a charge-up in MoS2 that prevents low energy electrons from escaping the surface within a period of a few femtoseconds after ion impact. We support these results by measuring the electron energy distribution for correlated pairs of electrons and transmitted ions. The majority of emitted primary electrons have an energy below 10 eVand are therefore subject to the dynamic charge-up effects at surfaces.

A myriad of phenomena in materials science and chemistry rely on quantum-level simulations of the electronic structure in matter. While moving to larger length and time scales has been a pressing issue for decades, such large-scale electronic structure calculations are still challenging despite modern software approaches and advances in high-performance computing.
The silver lining in this regard is the use of machine learning to accelerate electronic structure calculations -- this line of research has recently gained growing attention.
The grand challenge therein is finding a suitable machine-learning model during a process called hyperparameter optimization. This, however, causes a massive computational overhead in addition to that of data generation.
We accelerate the construction of neural network models by roughly two orders of magnitude by circumventing excessive training during the hyperparameter optimization phase. We demonstrate our workflow for Kohn-Sham density functional theory, the most popular computational method in materials science and chemistry.

Multiregime closure models for the two-fluid model often focus on continuous-dispersed and large-scale interface flow morphologies (Cerne, Petelin and Tiselj, 2021), (Hänsch et al., 2012), (Mathur et al., 2019).
Thin liquid films at solid walls, e.g. in annular flow or film condensation, so far have not been considered in a multi-regime two-fluid (MTF) model.
Rather, thin liquid films are currently treated as large-scale interfaces.
The film interface thus has to be resolved, which is conflicting with the two-fluid model approach and increases computational cost.
For the interface resolving volume-of-fluid method, coupling to a liquid film (LF) model was previously proposed to treat subgrid size liquid films (Kakimpa, Morvan and Hibberd, 2016).
Here, we adapt this approach to the framework of the MTF model.
A film thickness transport equation and film momentum equation are solved in a shell region of the two-fluid model volume domain.
Mass- and momentum transfer between both models is included depending on a critical film volume fraction in the first cell at the wall.
Thus a hybrid representation of liquid films depending on the local film thickness is obtained in the proposed LF-MTF model.
The implementation in the CFD solver STAR-CCM+ is outlined and a basic verification case is presented.
Validation results of LF-MTF model simulations against X-ray microtomographic data of horizontal annular flow (Porombka et al., 2021) show qualitative agreement and outline paths for further model improvement.
Finally, simulation results of droplet separators demonstrate the applicability of the LF-MTF model to industrial CFD.

This document summarizes the aMUSE activities carried on in the first six months of the
project (January-June 2022). For each Work Package, an overview of the progresses done
so far is reported. Outreach, dissemination and training activities are also listed.

Understanding the electronic transport properties of iron under high temperatures and pressures is essential for constraining geophysical processes. The difficulty of reliably measuring these properties calls for sophisticated theoretical methods that can support diagnostics. We present electrical conductivity results from simulating microscopic Ohm’s law using the real-time formalism of time-dependent density functional theory for conditions ranging from high-pressure solid at ambient temperature to earth-core conditions.

Die Präsentation im Rahmen eines Projekttreffens von "Circular by Design" stellt die wesentlichen Ergebnisse des Gutachtens vor.. Neben den gesetzlichen Grundlagen wird der aktuelle Stand in der Sammlung und Verwertung ebenso vorgestellt, wie gute Beispiele, die als Grundlage für die erarbeiteten Lösungsansätze und Handlungsempfehlungen dienen. ,

In water electrolyzer cells, active materials contain various fine-grained critical raw materials such as platinum group metals or rare earth elements. Although the readiness level of water electrolysis technology is high and large scale of hydrogen production is targeted worldwide, there has been no significant research on recycling of end of life (EOL) water electrolyzer cells. For a functioning circular economy, recycling processes for these valuable materials have to be developed especially on the fine particle scale below 100 μm.
The in-depth characterization of water electrolyzer cells and their components allows to assess their liberation behavior and subsequent separability based on different particle properties, e.g. size, density, wettability, etc. Thus, this paper aims at identifying the material composition and properties of proton exchange membrane electrolyzer cell (PEMEL) and high temperature electrolyzer cell (HTEL) before processing. In PEMEL, critical raw materials such as iridium, ruthenium, and platinum are used, while nickel, lanthanum, and yttrium are used in HTEL. Techniques such as automated mineralogical analysis (MLA), X-ray fluorescence spectroscopy and microscopy (XRF) and laser diffraction are used to identify the possibility of liberation. To ensure a high recovery rate of critical raw materials, the surface properties of individual component have been studied. Additional contact angle studies by means of pressed bubble and the particle attachment on single air bubbles revealed the wettability of membrane electrode assemblies and significant differences between the components. Furthermore, pH and salinity show to influence the wetting behaviour of the components. These findings provide the design of the separation study for EOL electrolyzer cells.

The exfoliation energy — quantifying the energy required to extract a two-dimensional (2D) sheet from the surface of a bulk
material — is a key parameter determining the synthesizability of 2D compounds. Here, using ab initio calculations, we present
a new group of non-van der Waals 2D materials derived from non-layered crystals which exhibit ultra low exfoliation energies.
In particular for sulfides, surface relaxations are essential to correctly describe the associated energy gain needed to obtain
reliable results. Taking into account long-range dispersive interactions has only a minor effect on the energetics and ultimately
proves that the exfoliation energies are close to the ones of traditional van der Waals bound 2D compounds. The candidates
with the lowest energies, 2D SbTlO3 and MnNaCl3, exhibit appealing electronic, potential topological, and magnetic
features as evident from the calculated band structures making these systems an attractive platform for fundamental and applied
nanoscience.

It is well known that structural defects have a remarkable influence on the optical, electrical, and catalytic properties of 2D materials. In addition to imaging utilization, irradiation with electron and ion beams allows precise control of defect generation by altering beam conditions and exposure dose4. We have studied the effects of ion irradiation on 2D materials by using first-principles calculations combined with analytical potential molecular dynamics. In particular, the defect production mechanisms for various free-standing and supported 2D targets were studied. The amount of damage in single-layer transition-metal dichalcogenides was explored under the impacts of noble gases with a wide range of energies and incident angles. We showed that ion irradiation can produce uniform pores in 2D transition metal dichalcogenides for applications such as gas separation. The possibility of changing defect concentrations opens a path for tuning electronic, and magnetic properties of 2D materials via a combination of thermal treatment and a reactive vapor. Moreover, defect engineering can be used to generate luminescent centers to enable quantum emitter applications.

Single-photon sources are one of the elementary building blocks for photonic quantum information and optical quantum computing [1]. One of the upcoming challenges is the monolithic photonic integration and coupling of single-photon emission, reconfigurable photonic elements and single-photon detection on a silicon chip in a controllable manner. Particularly, fully integrated single-photon emitters on-demand are required for enabling a smart integration of advanced functionalities in on-chip quantum photonic circuits [2].

This work presents a mask-free nanofabrication method involving a quasi-deterministic creation of scalable extrinsic color centers in silicon emitting in the optical telecom O-band [3] on a commercial silicon-on-insulator platform using focused ion beam writing. We also show the local writing of an intrinsic color center in silicon, which is linked to a tri-interstitial complex and reveals quantum emission close to the telecom band [4]. The successful integration of these telecom quantum emitters into photonic structures such as micro-resonators, nanopillars [5] and photonic crystals with sub-micrometer precision paves the way toward a monolithic, all-silicon-based semiconductor-superconductor quantum circuit.

[1]D. D. Awschalom et al.,Nature Photonics 12,516 (2018)
[2]J. C. Adcock et al.,IEEE, 27, 2, (2021)
[3]M. Hollenbach et al.,Optics Express 28,26111 (2020)
[4]Y. Baron et al.,arXiv:2108.04283 (2021)
[5]M. Hollenbach et al.,arXiv:2112.02680 (2021)

Radionuclide speciation inside long-term radioactive waste repositories needs to be
understood in order to ensure effective containment of the waste. Organic ligands
originating from the degradation of organic components inside such a repository can
possibly affect the mobility of radionuclides in solution. The present study focuses on
nitrilotriacetic acid, NTA, as a model molecule and europium, Eu(III), as a
nonradioactive analog with outstanding luminescence and magnetic properties.
The complexation of NTA with Eu(III) as a function of pH was studied using nuclear
magnetic resonance (NMR) spectroscopy. Samples were prepared with Eu(III) to NTA
ratios of 1:1 and 1:2 in D₂O with 1 M NaCl as background electrolyte to simulate high
ionic strength. The ¹H and ¹³C NMR spectra of the NTA solutions with Eu(III) show
clearly distinguishable signals for the free NTA and two Eu-NTA complexes, which is
indicative of a 1:1 and a 1:2 Eu-NTA complex. The interaction of Eu(III) with NTA is
relatively strong and favors the 1:2 Eu-NTA complex even in solution containing 1:1
Eu-NTA ratio, except in very acidic solutions. Time-resolved laser-induced
fluorescence spectroscopy (TRLFS) measurements yield quantitative information on
the complexation behavior.
As repository relevant cationic groundwater components, the influence of Ca(II) and
Al(III) on Eu(III) complexation with NTA is studied in detail with NMR spectroscopy.
This combination of NMR spectroscopy and TRLFS yields qualitative and quantitative
information on the coordination environment from the ligand’s and the metal ion’s
perspective, respectively. In subsequent studies focusing on ternary systems
comprising repository relevant solid phases (e.g. calcium aluminum silicate hydrate
(C-A-S-H) phases), radionuclides and organic ligands, this will allow the identification
of radionuclide speciation in solution and on solid phases.

Böhlen et al. [1] recently proposed a model that describes the magnitude of the normal tissue sparing Flash effect as a function of dose based on available in vivo data. The newly introduced flash modifying factor FMF translates doses applied at ultra-high dose rate to equivalent doses at conventional dose rate similar to the concept of relative biological effectiveness [1]. Primarily founded on rodent data, the model [1] includes only one study that demonstrated a dose-dependent Flash effect by length differences measured at 5 days-old zebrafish embryo (ZFE) after irradiation with electron doses of 5 – 12 Gy [2]. We studied this systematic overview about the available Flash data with great interest and acknowledged it as a very useful guidance for future Flash research. Coincidentally, we have just recently measured ZFE data in the high dose range (15 – 50 Gy) that appear to match very well with the existing rodent data.
Comparable to our previous studies at the ELBE accelerator [3, 4], one day-old ZFE were irradiated using electron beams of reference (mean dose rate 0.11 Gy/s) and ultra-high dose rate (UHDR; mean dose rate 0.9×105 Gy/s) (Fig. 1a). Normal tissue toxicity was quantified by analyzing the length deficit of the 5 days-old embryos compared to unirradiated controls. Since the controls grew on average 30% from irradiation to analysis this is the maximum length deficit that can be caused by irradiation. The derived FMF values extend the available ZFE data [2] and cover in a single experiment almost the entire dose range applied in the rodent studies for different tissues. Comparable to the rodent data (Fig. 1b) the ZFE FMF increases with dose.
The good agreement of our ZFE data with the rodent data [1] demonstrates the feasibility of the ZFE model for basic Flash effect studies, e.g., on the influence of physical beam parameters [3–6]. Hence, the ZFE model could be deployed as a high-throughput alternative to rodent studies at this translational level [5] promising the exploration of a large dose and dose rate range of clinically relevant beams.

We demonstrate a broadband photoconductive THz emitter compatible with femtosecond fiber lasers operating at wavelengths of 1.1 and 1.55 m. The emitted 1.5-cycle transient covers the spectral range up to 70 THz.

We utilize optical pump – THz probe spectroscopy to estimate electron mobility in strained GaAs/(In,Al)As core/shell nanowires. Our results demonstrate that strain-induced reduction of the effective electron mass leads to a remarkable increase of the mobility. The data analysis indicates an important role of the inhomogeneous plasmon broadening that may affect THz spectra of dense ensembles of nanowires.