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Abstract The occurrence of high stress concentrations in reactor components is a still intractable phenomenon encountered in fusion reactor design. Here, we observe and quantitatively model a non-linear high-dose radiation mediated microstructure evolution effect that facilitates fast stress relaxation in the most challenging low-temperature limit. In situ observations of a tensioned tungsten wire exposed to a high-energy ion beam show that internal stress of up to 2 GPa relaxes within minutes, with the extent and time-scale of relaxation accurately predicted by a parameter-free multiscale model informed by atomistic simulations. As opposed to conventional notions of radiation creep, the effect arises from the self-organisation of nanoscale crystal defects, athermally coalescing into extended polarized dislocation networks that compensate and alleviate the external stress.

Pulsed laser deposition and subsequent thermal treatment were used to create compact tungsten layers with various grain sizes (1μm, 100 nm, and 10 nm). The layers were self-damaged at room temperature up to 0.23 dpa using 20.3 MeV W ions and annealed in vacuum at 473 K or 673 K prior to exposure to deuterium plasma to populate the surviving displacement defects. Thermal desorption spectroscopy was used to measure deuterium retention and study the desorption profile. Rate-equation modeling of the desorption spectra was performed to study the behavior of individual traps at both annealing temperatures. After annealing the 1μm and 100 nm samples at 473 K, the deuterium retention was found to decrease by 24% and 9%, respectively, whereas the total deuterium retention in the 10 nm sample did not change. Annealing at 673 K reduced total deuterium retention by additional 27%, 14%, and 34% in the case of the samples with a grain size of 1μm, 100 nm, and 10 nm, respectively.

Linear Hashing is an important algorithm for many key-value stores in main memory. Spiral Storage was invented to overcome the poor fringe behavior of Linear Hashing, but after an influential study by Larson, it seems to have been discarded. Since almost 50 years have passed, we repeat Larson’s comparison with the in-memory implementation of both to see whether his verdict still stands. Our study shows that Spiral Storage has slightly better lookup performance but slightly poorer insert performance. However, Spiral Hashing has more predictable performance for inserts and, in particular, better fringe behavior.

Abstract Robotic systems facilitate relatively simple human–robot interaction for non-robot experts, providing the flexibility to implement different processes. In this context, shorter process times, as well as an increased product and process quality could be achieved. Robots short time-consuming processes, take over ergonomically unfavorable tasks and work efficiently all the time. In addition, flexible production is possible while maintaining or even increasing safety. This study describes the successful development of a dual-arm robot-based modular infrastructure and the establishment of an automated process for the reproducible production of nanoparticles. As proof of concept, a manual synthesis protocol for silica nanoparticle preparation with a diameter of about 200 nm as building blocks for photonic crystals was translated into a fully automated process. All devices and components of the automated system were optimized and adapted according to the synthesis requirements. To demonstrate the benefit of the automated nanoparticle production, manual (synthesis done by lab technicians) and automated syntheses were benchmarked. To this end, different processing parameters (time of synthesis procedure, accuracy of dosage etc.) and the properties of the produced nanoparticles were compared. We demonstrate that the use of the robot not only increased the synthesis accuracy and reproducibility but reduced the personnel time and costs up to 75%.

Extended service life of components is playing an increasingly important role in society and economy. Accordingly, this also applies to elastomeric materials, which are used for example for tires, seals, and hoses. These are often exposed to cyclic loading, with crack initiation and growth playing a decisive role. Corresponding phenomena have been investigated for many years and are still not fully understood. For the fatigue behavior, the crosslinking state of the material is of particular importance. This is accompanied by various production parameters, such as processing temperature and curing time, which have been of little importance in research to date. For this reason, plain strain test specimens out of nitrile butadiene rubber (NBR) were produced by injection molding at different mold temperatures and crosslinking times in the present work. With the aid of these, the crack growth rate at different crosslinking states under cyclic loading was investigated. It has been shown that a longer crosslinking time toward fully cured specimens results in a 20% reduction in dissipated energy, with a corresponding increase of the crack growth rate by the factor of 100. Furthermore, a 20 K increase in mold temperature during manufacturing of fully cured specimens leads to a four times slower crack growth.

Bone is a dynamic environment where osteocytes, osteoblasts, and mesenchymal stem/progenitor cells perceive mechanical cues and regulate bone metabolism accordingly. In particular, interstitial fluid flow in bone and bone marrow serves as a primary biophysical stimulus, which regulates the growth and fate of the cellular components of bone. The processes of mechano-sensory and -transduction towards bone formation have been well studied mainly in vivo as well as in two-dimensional (2D) dynamic cell culture platforms, which elucidated mechanically induced osteogenesis starting with anabolic responses, such as production of nitrogen oxide and prostaglandins followed by the activation of canonical Wnt signaling, upon mechanosensation. The knowledge has been now translated into regenerative medicine, particularly into the field of bone tissue engineering, where multipotent stem cells are combined with three-dimensional (3D) scaffolding biomaterials to produce transplantable constructs for bone regeneration. In the presence of 3D scaffolds, the importance of suitable dynamic cell culture platforms increases further not only to improve mass transfer inside the scaffolds but to provide appropriate biophysical cues to guide cell fate. In principle, the concept of dynamic cell culture platforms is rooted to bone mechanobiology. Therefore, this review primarily focuses on biophysical environment in bone and its translation into dynamic cell culture platforms commonly used for 2D and 3D cell expansion, including their advancement, challenges, and future perspectives. Additionally, it provides the literature review of recent empirical studies using 2D and 3D flow-based dynamic cell culture systems for bone tissue engineering.

Recently we have shown that thin (33 to 55 nm) oxide films on tungsten (W) prevent deuterium (D) uptake from a low-temperature plasma (5 eV/D; 370 K; 1.4 × 1024 D/m2) into metallic W. Here we continue this investigation with higher D fluence up to 2.3 × 1025 D/m2 and, additionally, with higher D energies up to 38 eV/D or a higher sample temperature of 500 K. We investigate the reduction mechanism of the oxide and determine under which conditions the permeation barrier effect for D breaks down. We show that during prolonged plasma exposure at 5 eV/D and 370 K, the W-enriched zone that forms at the surface of the oxide stops growing and continues to protect the oxide beneath it against further reduction. For a fluence of 1.6 × 1025 D/m2, an originally 55 nm thick oxide film reduces D uptake into the metal by 99 %. D enters the metal solely by small cracks in the oxide that form during reduction by the plasma. For higher temperature or D energies, the reduction becomes stronger and more inhomogeneous. D uptake into the metal increases proportional to the area of oxide/metal interface on which the oxide is reduced. The new experiments confirm our previous assumption that D uptake into W is blocked due to the difference in enthalpy of solution of D in W oxide and metallic W. D can only enter the metal once the oxide at the interface is sufficiently reduced. Based on the obtained oxide reduction rates, we made a first tentative estimate of the relevance of naturally occurring W oxide films for D uptake in the plasma-facing components of a fusion reactor. We found that the natural oxide will have none or only a very minor effect in this case.

A damage-induced hydrogen trap creation model is proposed, and parameters for tungsten are identified using experimental data. The methodology for obtaining these parameters using thermo-desorption analysis spectra data is outlined. Self-damaged and optionally annealed tungsten samples have undergone TDS analysis, which has been analysed to identify the properties of extrinsic traps induced by the damage and to determine how they evolve with damage and annealing temperature. A parametric study investigated the impact of the damage rate and temperature on tritium inventories in tungsten. Tritium transport simulations have been performed with FESTIM considering a 1D model of a 2 mm sample of tungsten with damage rates and temperatures varying from 0– ${10^{2}}$ dpa/fpy and 600–1300 K, respectively. The results show that after 24 h simultaneous exposure to neutron damage at ${10^{2}}$ dpa/FPY and tritium implantation at 700 K, tritium inventories can increase by up to four orders of magnitude when damaged at a rate of ${10^{2}}$ dpa/FPY compared to undamaged, defect-free tungsten, increasing further to five orders of magnitude after one full power year. The time taken to reach retention saturation shows the need for kinetic models of trapping properties on time scales relevant to reactor operation. The trap-creation model parameterisation procedure can be used to investigate neutron damage effects on other fusion-relevant materials such as EUROFER, Inconel and more.

Abstract The fate determination of bone marrow mesenchymal stem/stromal cells (BMSC) is tightly regulated by mechanical cues, including fluid shear stress. Knowledge of mechanobiology in 2D culture has allowed researchers in bone tissue engineering to develop 3D dynamic culture systems with the potential for clinical translation in which the fate and growth of BMSC are mechanically controlled. However, due to the complexity of 3D dynamic cell culture compared to the 2D counterpart, the mechanisms of cell regulation in the dynamic environment remain relatively undescribed. In the present study, we analyzed the cytoskeletal modulation and osteogenic profiles of BMSC under fluid stimuli in a 3D culture condition using a perfusion bioreactor. BMSC subjected to fluid shear stress (mean 1.56 mPa) showed increased actomyosin contractility, accompanied by the upregulation of mechanoreceptors, focal adhesions, and Rho GTPase‐mediated signaling molecules. Osteogenic gene expression profiling revealed that fluid shear stress promoted the expression of osteogenic markers differently from chemically induced osteogenesis. Osteogenic marker mRNA expression, type 1 collagen formation, ALP activity, and mineralization were promoted in the dynamic condition, even in the absence of chemical supplementation. The inhibition of cell contractility under flow by Rhosin chloride, Y27632, MLCK inhibitor peptide‐18, or Blebbistatin revealed that actomyosin contractility was required for maintaining the proliferative status and mechanically induced osteogenic differentiation in the dynamic culture. The study highlights the cytoskeletal response and unique osteogenic profile of BMSC in this type of dynamic cell culture, stepping toward the clinical translation of mechanically stimulated BMCS for bone regeneration.

The organ-specific microbiome plays a crucial role in tissue homeostasis, among other things by inducing regulatory T cells (Treg). This applies also to the skin and in this setting short chain fatty acids (SCFA) are relevant. It was demonstrated that topical application of SCFA controls the inflammatory response in the psoriasis-like imiquimod (IMQ)-induced murine skin inflammation model. Since SCFA signal via HCA2, a G-protein coupled receptor, and HCA2 expression is reduced in human lesional psoriatic skin, we studied the effect of HCA2 in this model. HCA2 knock-out (HCA2-KO) mice reacted to IMQ with stronger inflammation, presumably due to an impaired function of Treg. Surprisingly, injection of Treg from HCA2-KO mice even enhanced the IMQ reaction, suggesting that in the absence of HCA2 Treg switch from a suppressive into a proinflammatory type. HCA2-KO mice differed in the composition of the skin microbiome from wild type mice. Co-housing reversed the exaggerated response to IMQ and prevented the alteration of Treg, implying that the microbiome dictates the outcome of the inflammatory reaction. The switch of Treg into a proinflammatory type in HCA2-KO mice could be a downstream phenomenon. This opens the opportunity to reduce the inflammatory tendency in psoriasis by altering the skin microbiome.

New technologies for non-volatile memories combine the speed and byte addressability of current memory technologies with the low cost, density, and non-volatility of current storage technologies. They use energy only when writing or reading data. While some newer technologies have practically unlimited endurance, others, such as Phase Change Memory do not. However, this limited endurance surpasses that of solid state drives by several orders of magnitude. They can be integrated into the current memory storage hierarchy as a replacement for DRAM. To manage limited endurance, age-based wear leveling divides the memory into pages and counts the number of writes to a page. Pages with high counts can then be relegated to store more stable data. Counters experience “write concentration” as they are incremented as frequently as a page is written, but the changes are concentrated in a much smaller area around the least significant bit. Current designs store page write counters with the page table in the main memory unit.We propose and investigate an alternative counter design based on Gray codes that distributes the bit-flips resulting from the increments over the vast majority of the bits making up the counter. This is a bit-flip aware data structure that can be used in other contexts as well. We show that this design allows us to integrate the page counters into the phase change memory device. We also investigate counters using error control codes.

Vascular access in severely injured pediatric trauma patients is associated with time-critical circumstances and low incidences, whereas only scarce literature on procedure performance is available. The purpose of this study was to analyze the performance of different vascular access procedures from the first contact at the scene until three hours after admission. Intubated pediatric trauma patients admitted from the scene to a single Level I trauma center between 2008 and 2019 were analyzed regarding intravenous (IV) and intraosseous (IO) accesses, central venous catheterization (CVC) and arterial line placement. Sixty-five children with a median age of 14 years and median injury severity score of 29 points were included, of which 62 (96.6%) underwent successful prehospital IV or IO access by emergency medical service (EMS) physicians, while it failed in two children (3.1%). On emergency department (ED) admission, IV cannulas of prehospital EMS had malfunctions or were dislodged in seven of 55 children (12.7%). IO access was performed in 17 children without complications, and was associated with younger age, higher injury severity and higher mortality. Fifty-two CVC placements (58 attempts) and 55 arterial line placements (59 attempts) were performed in 45 and 52 children, respectively. All CVC and arterial line placements were performed in the ED, operating room (OR) and intensive care unit (ICU). Ten mechanical complications related to CVC placement (17.8%) and seven related to arterial line placement (10.2%) were observed, none of which had outcome-relevant consequences. This case series suggests that mechanical issues of vascular access may frequently occur, underlining the need for special preparedness in prehospital, ED, ICU and OR environments.

Various perfusion bioreactor systems have been designed to improve cell culture with three-dimensional porous scaffolds, and there is some evidence that fluid force improves the osteogenic commitment of the progenitors. However, because of the unique design concept and operational configuration of each study, the experimental setups of perfusion bioreactor systems are not always compatible with other systems. To reconcile results from different systems, the thorough optimization and validation of experimental configuration are required in each system. In this study, optimal experimental conditions for a perfusion bioreactor were explored in three steps. First, an in silico modeling was performed using a scaffold geometry obtained by microCT and an expedient geometry parameterized with porosity and permeability to assess the accuracy of calculated fluid shear stress and computational time. Then, environmental factors for cell culture were optimized, including the volume of the medium, bubble suppression, and medium evaporation. Further, by combining the findings, it was possible to determine the optimal flow rate at which cell growth was supported while osteogenic differentiation was triggered. Here, we demonstrated that fluid shear stress up to 15 mPa was sufficient to induce osteogenesis, but cell growth was severely impacted by the volume of perfused medium, the presence of air bubbles, and medium evaporation, all of which are common concerns in perfusion bioreactor systems. This study emphasizes the necessity of optimization of experimental variables, which may often be underreported or overlooked, and indicates steps which can be taken to address issues common to perfusion bioreactors for bone tissue engineering.

Advanced Therapy Medicinal Products (ATMP) provide promising treatment options particularly for unmet clinical needs, such as progressive and chronic diseases where currently no satisfying treatment exists. Especially from the ATMP subclass of Tissue Engineered Products (TEPs), only a few have yet been translated from an academic setting to clinic and beyond. A reason for low numbers of TEPs in current clinical trials and one main key hurdle for TEPs is the cost and labor-intensive manufacturing process. Manual production steps require experienced personnel, are challenging to standardize and to scale up. Automated manufacturing has the potential to overcome these challenges, toward an increasing cost-effectiveness. One major obstacle for automation is the control and risk prevention of cross contaminations, especially when handling parallel production lines of different patient material. These critical steps necessitate validated effective and efficient cleaning procedures in an automated system. In this perspective, possible technologies, concepts and solutions to existing ATMP manufacturing hurdles are discussed on the example of a late clinical phase II trial TEP. In compliance to Good Manufacturing Practice (GMP) guidelines, we propose a dual arm robot based isolator approach. Our novel concept enables complete process automation for adherent cell culture, and the translation of all manual process steps with standard laboratory equipment. Moreover, we discuss novel solutions for automated cleaning, without the need for human intervention. Consequently, our automation concept offers the unique chance to scale up production while becoming more cost-effective, which will ultimately increase TEP availability to a broader number of patients.

ITER will use beryllium as a plasma-facing material in the main chamber, covering a total surface area of about 620 m2. Given the importance of beryllium erosion and co-deposition for tritium retention in ITER, significant efforts have been made to understand the behaviour of beryllium under fusion-relevant conditions with high particle and heat loads. This paper provides a comprehensive report on the state of knowledge of beryllium behaviour under fusion-relevant conditions: the erosion mechanisms and their consequences, beryllium migration in JET, fuel retention and dust generation. The paper reviews basic laboratory studies, advanced computer simulations and experience from laboratory plasma experiments in linear simulators of plasma–wall interactions and in controlled fusion devices using beryllium plasma-facing components. A critical assessment of analytical methods and simulation codes used in beryllium studies is given. The overall objective is to review the existing set of data with a broad literature survey and to identify gaps and research needs to broaden the database for ITER.

We studied the uptake of deuterium (D) into tungsten (W) through thin films of W oxide. Two surface oxide films with thicknesses of 33 and 55 nm were thermally grown on W substrates. In the following, the oxidized samples were exposed to low-energy D (5 eV/D) from a D plasma at a sample temperature of 370 K. A defect-rich layer of self-damaged W underneath the oxide was used as a getter layer to enable the detection of D that penetrates the oxide film. Depth-resolved concentration profiles of D and oxygen (O) were obtained after the plasma exposure by nuclear reaction analysis and Rutherford backscattering spectrometry. We have found that oxygen is partially removed from the first 100 × 1019 atoms/m2 (≈ 13.5 nm) of the oxide film by the D plasma which leads to a W enrichment in the near surface region. Independent of the oxide thickness, an oxygen removal rate of (5.4 ± 0.7) × 10−4 O atoms per incident D atom was observed. Furthermore, D accumulates in the oxide film to concentrations of up to 1.3 at. %, but does not penetrate into the underlying self-damaged W. After a storage period of ten months at room temperature in vacuum, the D content in the oxide layer has decreased substantially, but still no D has penetrated into the metallic W. It is evident that surface oxide films on W effectively block the D uptake into metallic W. However, the D uptake into metallic W is not limited by the transport in the oxide film itself. D diffuses fast throughout the oxide but is stopped at the interface to the metallic W. We attribute this behavior to the difference in the heat of solution for D in W oxide and metallic W. D cannot overcome this barrier once it is thermalized to 370 K within the W oxide film.

The fatal determination of bone marrow mesenchymal stem/stromal cells (BMSC) is closely associated with mechano-environmental factors in addition to biochemical clues. The aim of this study was to induce osteogenesis in the absence of chemical stimuli using a custom-designed laminar flow bioreactor. BMSC were seeded onto synthetic microporous scaffolds and subjected to the subphysiological level of fluid flow for up to 21 days. During the perfusion, cell proliferation was significantly inhibited. There were also morphological changes, with F-actin polymerisation and upregulation of ROCK1. Notably, in BMSC subjected to flow, mRNA expression of osteogenic markers was significantly upregulated and RUNX2 was localised in the nuclei. Further, under perfusion, there was greater deposition of collagen type 1 and calcium onto the scaffolds. The results confirm that an appropriate level of fluid stimuli preconditions BMSC towards the osteoblastic lineage on 3D scaffolds in the absence of chemical stimulation, which highlights the utility of flow bioreactors in bone tissue engineering.

Gonorrhea, a sexually transmitted disease caused by the bacteria Neisseria gonorrhoeae , is characterized by a large number of neutrophils recruited to the site of infection. Therefore, proper modeling of the N. gonorrhoeae interaction with neutrophils is very important for investigating and understanding the mechanisms that gonococci use to evade the immune response. We have used a combination of a unique human 3D tissue model together with a dynamic culture system to study neutrophil transmigration to the site of N. gonorrhoeae infection. The triple co-culture model consisted of epithelial cells (T84 human colorectal carcinoma cells), human primary dermal fibroblasts, and human umbilical vein endothelial cells on a biological scaffold (SIS). After the infection of the tissue model with N. gonorrhoeae , we introduced primary human neutrophils to the endothelial side of the model using a perfusion-based bioreactor system. By this approach, we were able to demonstrate the activation and transmigration of neutrophils across the 3D tissue model and their recruitment to the site of infection. In summary, the triple co-culture model supplemented by neutrophils represents a promising tool for investigating N. gonorrhoeae and other bacterial infections and interactions with the innate immunity cells under conditions closely resembling the native tissue environment.

Since time began there has been a strong fascination in foreseeing the behavior of buildings and constructions. Now In order to predict this behavior, we use experimental, and increasingly more time- and cost-effective, computational simulations. Finite Element Analysis (FEA) is a method that has become increasingly prevalent and has become firmly established in aviation and vehicle construction for decades. In recent years, there has been a marked growth in the use of numerical simulations for the verification of adhesive bonds, particularly in façade development where polymeric materials such as sealants or thermoplastic spacers are becoming increasingly important. This is partly driven by their expansion stress behavior, which differs greatly from the classic linear behavior of established materials such as aluminum, steel or glass. The present work uses non-linear material laws for FEA and exhibits the behavior of the sealant joint in various load scenarios on several projects. The presented case studies show that the developed calculation methods can be used to describe polymeric materials very precisely and thus simulate a wide variety of load scenarios on glued components in time and money saving manner.

Inadvertent tracheal tube misplacement and particularly endobronchial intubation are well-known complications of emergency endotracheal intubation (ETI) in pediatric trauma patients, which require repositioning of the tube to avoid impairment of gas exchange. The main aim of study was to identify the frequency of tube misplacement and associated factors of pediatric trauma patients who received ETI either by prehospital physician-staffed emergency medical service (EMS), or at emergency department (ED) admission to a single level-1 trauma center. Sixty-five patients (median age 14 years and median injury severity score 29) were included. Of these, 30 underwent helicopter EMS ETI, 29 ground EMS ETI, and 6 ED ETI. Seventeen cases (26%) of tracheal tube misplacement were recognized. After multivariable analysis, tracheal tube misplacement was independently negatively associated with body weight (OR 0.86; 95% CI, 0.76–0.99; p = 0.032) and helicopter EMS ETI (OR 0.20; 95% CI, 0.04–0.97; p = 0.036). Two of nineteen patients received tube thoracostomy due to endobronchial intubation. Mortality and length of stay were comparable in patients with misplaced tubes and correctly placed tubes. The results suggest that particularly small children require attention to avoid tracheal tube misplacement, which emphasizes the need for special training. Helicopter EMS physicians’ expertise might be beneficial in prehospital pediatric trauma patients requiring advanced airway management.

The presented investigation focuses on the development of a novel microgap reactor concept for the photocatalytic degradation of micropollutants from aqueous solutions with titanium dioxide-based catalysts immobilized by spray coating. Combinatorial experiment designs were utilized in order to study the influence of the microgap width, irradiance and catalyst layer thickness on the conversion of 17 α-ethinyl estradiol. The impact of catalyst-doping is discussed as well. Regarding conversion analyses, LC-MS/MS and GC-MS techniques were deployed, while XRD, ESEM and BET were utilized for catalyst characterization. The results show that the built-up microgap reactor system enables a conversion of 65% within a residence time of 2.7 min with UV-A irradiation and under steady flow conditions. Thus, the presented bench scale photocatalysis reactor provides promising fundamental findings for the future development of pilot scale approaches. With the deployment of industrial catalysts and base materials, microgap reactor photocatalytic degradation represents an attractive technology for large-scale application.

Surface compositional changes of iron-tungsten films by deuterium (D) ion bombardment were studied by means of medium energy ion scattering, elastic recoil detection analysis and Rutherford backscattering spectrometry. The energy of the bombarding ions was 200eV/D and the fluence was varied from 1021 D/m2 to 1024D/m2. A significant increase of the tungsten concentration within the 20nm closest to the sample surface, caused by preferential sputtering of iron, was seen for the films exposed 1023D/m2 or more. In the sample exposed to the highest fluence, 1024D/m2, the concentration of tungsten was increased from an initial 1.7 at. % up to approximately 24 at. % averaged over the 5nm closest to the surface. The analysis was complicated by the presence of oxygen on the sample surfaces. In order to study the thermal stability of the tungsten enriched layer, the sample initially exposed to 1023 D/m2 at room temperature was heated to 400 °C in the measurement chamber for medium energy ion scattering and several spectra were recorded at intermediate temperatures. The obtained data showed that the layer was relatively stable below 200 °C whereas a drastic change in the film composition occurred between 200 °C and 250 °C due to interdiffusion of iron and silicon, the latter of which was the substrate material. The surface morphologies of the films were probed with atomic force microscopy showing that protrusions of 10–100nm width appeared after deuterium bombardment at fluences higher than 1022D/m2. Keywords: Eurofer, Model film, ToF-MEIS, Preferential sputtering, Surface enrichment

The dynamic erosion behaviour of iron-tungsten (Fe-W) model films (with 1.5 at% W) resulting from 250eV deuterium (D) irradiation is investigated under well-defined laboratory conditions. For three different impact angles (0°, 45° and 60° with respect to the surface normal) the erosion yield is monitored as a function of incident D fluence using a highly sensitive quartz crystal microbalance technique (QCM). In addition the evolution of the Fe-W film topography and roughness with increasing fluence is observed using an atomic force microscope (AFM). The mass removal rate for Fe-W is found to be comparable to the value of a pure Fe film at low incident fluences but strongly decreases with increasing D fluence. This is consistent with earlier observations of a substantial W enrichment at the surface due to preferential Fe sputtering. The reduction of the mass removal rate is initially more pronounced for irradiation under oblique angles as compared to normal incidence, but the differences vanish for fluences > 2·1023D/m². High resolution AFM images reveal that continued ion irradiation leads to significant surface roughening and (depending on ion impact angle) formation of nanodots or nano-ripples. This may indicate that the W enrichment at the surface due to preferential sputtering of Fe is not exclusively responsible for the observed reduction in erosion with increasing D fluence. Keywords: Plasma-wall-interaction, Sputtering, Erosion, Iron-tungsten, Ripple formation

To optimize the Sabatier process, quaternary supported catalyst materials are synthesized and tested. The syntheses are performed by the industrially established, reproducible and automated methods of impregnation and sol–gel synthesis. The screening of the 588 quaternary catalysts is carried out in a specially designed 10-fold parallel gas flow micro-structured reactor as wall catalysts in sequential operation mode at a temperature of T = 573 K and a pressure of p = 15 bar. For the description of the activity, the reaction parameters CO2 conversion, CH4 yield, and CH4/CO2 selectivity are used. These are determined by analyses of the gas phase composition using µGC-FID. The catalysts with the highest activities are validated in a micro-structured reactor with similar characteristics as the screening reactor in the temperature range between T = 573–673 K and a pressure of p = 15 bar. Characterization by powder X-ray diffraction, Raman spectra, and scanning transmission electron microscopic images data on the phase and element distribution after calcination and reduction was conducted.

The rising pollution of surface water by endocrine disruptive chemicals (EDCS) could lead to the persistent harm of aquatic wildlife. Addressing this concern, advanced waste water treatment techniques should be established in addition to the present sewage treatment. Therefore, the promising advanced oxidation process of photocatalysis is discussed. With the aim of establishing a novel high throughput screening approach for photocatalysts, a workflow resting upon the use of a self-constructed 60-fold parallel stirring UV-A LED photoreactor, followed by parallel sample extraction by SPE and sequential automated analysis by GC-MS, was developed, and is presented in this article. With the described system, TiO2-based photocatalysts, doped with different amounts of zinc, and synthesised by a sol-gel-route, were tested regarding their activity in the photocatalytic degradation of the synthetic estrogen 17α-ethinylestradiol. Thereby, the functional behavior of the photoreactor system and its applicability in a high throughput process could be evaluated. As a result of the catalyst screening, TiO2 catalysts with low amounts of zinc were found with a significantly higher activity, compared to undoped TiO2. In conclusion, the presented system provides an easily accessible high throughput method for a variety of photocatalytic experiments.

A unique high-throughput approach to identify new catalysts for total oxidation of methane from the exhaust gas of biogas-operated lean-burn engines is presented. The approach consists of three steps: (1) A primary screening using emission-corrected Infrared Thermography (ecIRT). (2) Validation in a conventional plug flow gas phase reactor using a model exhaust gas containing CH4, O2, CO, CO2, NO, NO2, N2O, SO2, H2O. (3) Ageing tests using a simplified exhaust gas (CH4, O2, CO2, SO2, H2O). To demonstrate the efficiency of this approach, one selected dataset with a sol-gel-based catalysts is presented. Compositions are 3 at.% precious metals (Pt, Rh) combined with different amounts of Al, Mn, and Ce in the form of mixed oxides. To find new promising materials for the abatement of methane, about two thousand different compositions were synthesized and ranked using ecIRT, and several hundred were characterized using a plug flow reactor and their ageing behaviour was determined.

We applied temperature-programmed desorption (TPD) spectroscopy to study the bonding of hydrogen in amorphous hydrogenated carbon (a−C:H) films. Typical hard plasma-deposited a−C:H films with an initial hydrogen content (H/(H+C)) of about 30% were used as samples. About 85% of the initial hydrogen content is released in the form of H2, the rest in the form of hydrocarbons. Using a temperature ramp of 15 K/min, release of hydrogen starts at about 600 K with a first peak at about 875 K and a broad shoulder around 1050 K. The peak positions depend on the temperature ramp. This fact was exploited to determine the pre-exponential factor for an analytic analysis of the release spectra. This analysis revealed a pre-exponential factor of ν = 1 × 10 16 1/s, which deviates significantly from the frequently assumed prefactor 1 × 10 13 1/s. This higher prefactor leads to a shift in the determined binding energies by about +0.5 eV. Standard TPD measurements with linear temperature ramps up to 1275 K were complemented by so-called “ramp and hold” experiments with linear ramps up to certain intermediate temperatures and holding the samples for different times at these temperatures. Such experiments provide valuable additional data for investigation of the thermal behavior of the investigated films. Our experiments prove that the width of the hydrogen release spectrum is determined by a distribution of binding energies rather than release kinetics or diffusive effects. This binding energy distribution has a peak at about 3.1 eV and a shoulder at higher energies extending from about 3.6 to 3.9 eV.

Fretting tests were conducted with five different thermoplastic polyurethanes against a steel ball. Their fretting behaviors were investigated under various test parameters, such as normal load and displacement amplitude. In order to test the sliding performances, tribological tests were conducted using a ring-on-disc setup. The results show that their fretting behaviors can be related to the dynamic mechanical properties, which were characterized by dynamic mechanical analysis (DMA). The three fretting regimes were identified by means of hysteresis and wear scar analysis. In addition, investigations were carried out until the transition regimes occurred. Different wear processes were revealed for each of the three regimes. Differences were identified using dissipated energy. The profiles of wear scars and the counterparts were analyzed using a microscope. The coefficient of friction was calculated separately for the partial slip and gross slip regimes. In the mixed fretting regime, the coefficient of friction is almost at the same level among the five materials. In the partial slip regime, however, it can be distinguished. Temperature measurements were conducted on the counterparts during the tests. Overall, the material that showed the best tribological properties also performed the best in the fretting tests.

For a long service time, fatigue has been a typical problem that mechanical sealing materials face. How does it relate to tribological performance? In this study, filled and unfilled thermoplastic polyurethanes (TPUs) were investigated. Dumbbell and faint wait pure shear (FWPS) specimens were used to characterize the fatigue properties and crack growth rate of TPUs, respectively. Additionally, to identify the impact of temperature on fatigue tests, the tests were conducted at room temperature and 80 °C. Different tribological tests were conducted to investigate their tribological properties. Fracture surfaces from fatigue tests and worn surfaces from tribological tests were analyzed using a scanning electron microscope (SEM). Two wear models were verified to correlate between fatigue and tribological properties; one of the models is better for rough counter surfaces, while the other is advantageous if the counter surface is smooth.

Concerning the still rising demand for oil and gas products, the development of new reliable materials to guarantee the facility safety at extreme operating conditions is an utmost necessity. The present study mainly deals with the influence of different carbon black (CB) filled hydrogenated nitrile butadiene rubber (HNBR), which is a material usually used in sealing applications, on the rapid gas decompression (RGD) resistance in harsh environments. Therefore, RGD component level tests were conducted in an autoclave. The supporting mechanical and dynamic mechanical property analysis, the microscopic level investigations on the material and failure analysis were conducted and are discussed in this work. Under the tested conditions, the samples filled with smaller CB primary particles showed a slightly lower volume increase during the compression and decompression phases; however, they steered to a significantly lower resistance to RGD. Transmission electron micrographs revealed that the samples filled with smaller CB particles formed larger structures as well as densified filler networks including larger agglomerates and as a consequence a decrease effective matrix component around the CB particles. Apparently, at higher loading conditions, which already deliver a certain level of mechanical stresses and strains, the densified filler network, and especially a lower amount of effective matrix material composition, adversely affect the RGD resistance. SEM-based fracture analysis did not identify any influence of the CB grades tested on the crack initiation site; however, it revealed that the cracks initiated from existing voids, hard particles, or low strength matrix sites and propagated to the outer surface.

Tissue dehydration results in three major types of exsiccosis--hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring.

The common usages of elastomeric components in oil and gas field applications are in dynamic atmospheres; especially sealing appliances that are in relative motion when interacting with surfaces. Therefore, their performance and service life mainly depend on the wear and friction characteristics in use. The objective of this scientific work is to identify the effect of swelling-induced ageing on the tribological properties and surface damage mechanisms of hydrogenated nitrile butadiene rubber (HNBR) in contact with different liquids. Furthermore, the investigation of the co-relation between mechanical properties and surface properties in the tested conditions is indispensable. In the swollen state, deteriorated mechanical properties were observed; however, in de-swollen conditions, the mechanical properties were restored. As far as the surface characterization is concerned, when the HNBR was swollen by a standard IRM 903 solvent, its wear was greater compared with the un-swollen specimen (1.1 times) despite the lower coefficient of friction (COF) (reduced by ~25%) and surface temperature (reduced by ~2.4 °C). In the de-swollen condition, wear was even greater (6 times), but the COF and surface temperature were situated in between those recorded in the swollen and un-swollen conditions. With swelling, greater wear damage and lower COF were observed; higher surface ageing (softness), which eases crack growth, created bigger debris. Under the conditions used, in the de-swollen states, the bulk mechanical properties were almost recovered, in contrast to the surface properties, which were still significantly impaired.

The liver X receptor α (LXRα) is a ligand-dependent nuclear receptor and the major regulator of reverse cholesterol transport in macrophages. This makes it an interesting target for mechanistic study and treatment of atherosclerosis.We optimized a promising stilbenoid structure (STX4) in order to reach nanomolar effective concentrations in LXRα reporter-gene assays. STX4 displayed the unique property to activate LXRα effectively but not its subtype LXRβ. The potential of STX4 to increase transcriptional activity as an LXRα ligand was tested with gene expression analyses in THP1-derived human macrophages and oxLDL-loaded human foam cells. Only in foam cells but not in macrophage cells STX4 treatment showed athero-protective effects with similar potency as the synthetic LXR ligand T0901317 (T09). Surprisingly, combinatorial treatment with STX4 and T09 resulted in an additive effect on reporter-gene activation and target gene expression. In physiological tests the cellular content of total and esterified cholesterol was significantly reduced by STX4 without the undesirable increase in triglyceride levels as observed for T09.STX4 is a new LXRα-ligand to study transcriptional regulation of anti-atherogenic processes in cell or ex vivo models, and provides a promising lead structure for pharmaceutical development.