Evaluation of the mechanical behavior of W7-X central support connections by means of semi-automated FE analysis

The stellarator Wendelstein 7-X is under construction at the Max-Planck-Institut für Plasmaphysik in Greifswald. Its superconducting coil system is fixed by a massive structure. During machine operation the coils exert high forces and moments against each other and the central support structure (CSS). Therefore, the detailed analysis of the coil to CSS connections, the so-called central support elements (CSE), is a critical item. The major details of the design have been frozen; nevertheless, there is still need for detailed analysis of the CSEs due to assembly issues, and later on for exploring operational limits of the machine. These analyses have to be performed quickly, reliably, and shall provide results in a standardized form to enable timely responses to the assembly team. Special numerical tools – finite element (FE) parametric models of CSEs – have been developed for the purpose of such analyses. In the models, the geometry, material properties, contact conditions, loads as well as results presentation are defined in a parametric way. The use of the developed models for the definition of the final weld parameters, bolt preloads, assessment of acceptable tolerances, and optimal positions of the CSE-wedges before welding is also discussed.     

Production of isobutylene from acetone over micro–mesoporous catalysts

The production of isobutylene from acetone over micro–mesoporous catalysts with different mesopore contents, which have been prepared using hydrothermal recrystallization of mordenite (MOR) zeolite modified with cesium acetate by incipient wetness impregnation, has been studied. It has been shown that cesium is inserted into the cation positions during the modification, at the same time the number of Brønsted acid sites in the samples decreased. It has been found that an increase in the content of mesopores in the catalyst leads to an increase in the initial rates of acetone conversion and isobutylene formation as a result of removing diffusion limitations. Brønsted acid sites have been shown to be preferable for the selective production of isobutylene from acetone. Micro–mesoporous materials operate more stably as compared to microporous materials.     

Relation between microstructure and glass transition temperature of poly[(methyl methacrylate)‐co‐(ethyl acrylate)]

The glass transition temperature of a series of samples of the poly[(methyl methacrylate)‐co‐(ethyl acrylate)] copolymer, synthesized at low conversion, were calculated theoretically using the equations of Barton and Johnston. The values obtained are more precise when the probabilities of the compositional diads are derived from the ¹³C NMR data instead of the classical method utilizing reactivity ratios. This can be observed more clearly when the copolymer samples are synthesized at high conversion. Introduction of configuration (tacticity) at the diad level confirms the above observations and slightly improves the calculated values of T_g compared to the initial formulae which were only taking into account the compositional sequences of the copolymer. © 2001 Society of Chemical Industry     

Radiosensitization of Human Leukemic HL-60 Cells by ATR Kinase Inhibitor (VE-821): Phosphoproteomic Analysis

DNA damaging agents such as ionizing radiation or chemotherapy are frequently used in oncology. DNA damage response (DDR)—triggered by radiation-induced double strand breaks—is orchestrated mainly by three Phosphatidylinositol 3-kinase-related kinases (PIKKs): Ataxia teleangiectasia mutated (ATM), DNA-dependent protein kinase (DNA-PK) and ATM and Rad3-related kinase (ATR). Their activation promotes cell-cycle arrest and facilitates DNA damage repair, resulting in radioresistance. Recently developed specific ATR inhibitor, VE-821 (3-amino-6-(4-(methylsulfonyl)phenyl)-N-phenylpyrazine-2-carboxamide), has been reported to have a significant radio- and chemo-sensitizing effect delimited to cancer cells (largely p53-deficient) without affecting normal cells. In this study, we employed SILAC-based quantitative phosphoproteomics to describe the mechanism of the radiosensitizing effect of VE-821 in human promyelocytic leukemic cells HL-60 (p53-negative). Hydrophilic interaction liquid chromatography (HILIC)-prefractionation with TiO₂-enrichment and nano-liquid chromatography—tandem mass spectrometry (LC-MS/MS) analysis revealed 9834 phosphorylation sites. Proteins with differentially up-/down-regulated phosphorylation were mostly localized in the nucleus and were involved in cellular processes such as DDR, all phases of the cell cycle, and cell division. Moreover, sequence motif analysis revealed significant changes in the activities of kinases involved in these processes. Taken together, our data indicates that ATR kinase has multiple roles in response to DNA damage throughout the cell cycle and that its inhibitor VE-821 is a potent radiosensitizing agent for p53-negative HL-60 cells.     

Temporal characteristics of light collection in the liquid scintillation counter with a volume of 1.5 m<Superscript>3</Superscript> and quasi-mirror reflection

The temporal behavior of light collection in the 1.5-m³-volume mirror-reflecting counter filled with a highly transmitting liquid scintillator has been investigated. Using the Monte Carlo method and assuming that the luminescence decay time of the liquid scintillator is zero (τ_LS = 0), it has been ascertained that, in the case of a short flash in a counter, the exponential phase of light collection is characterized by time τ_col = 15.0 ± 1.7 ns, which is does not depend on scattering of light in the medium. The measured exponent index τ_act = 37 ± 3 ns of an actual pulse due to a muon is determined both by light collection time τ_col ≈ 15 ns and luminescence decay time τ_LS ≈ 20 ns of the scintillator in the large-volume counter.     

Hydroprocesssing of light gas oil — rape oil mixtures

Two series of experiments of hydroprocessing of light gas oil - rape oil mixtures were carried out. The reactor feed was composed of raw material: first series — 10 wt.% rape oil and 90 wt.% of diesel oil; second series — 20 wt.% rape oil and 80 wt.% of diesel oil.     

Effect of annealing on cathodoluminescence of synthetic zincite single crystals

We have studied the effect of annealing on the luminescent properties of zincite single crystals grown from hydrothermal solutions. Annealing in the temperature range of 400–700°C increases the edge cathodoluminescence (CL) intensity in zincite. At the same time, raising the annealing temperature from 800 to 1100°C leads to quenching of the edge emission and increases the intensity of the green band. In addition, annealing leads to broadening of the edge luminescence band and shifts it to lower energies. In contrast, annealing shifts the impurity band to higher energies. The observed changes in the CL behavior of zincite are tentatively interpreted in terms of the temperature effect on the concentration of structural defects, in particular, oxygen vacancies and their complexes.     

Changes in Molecular Characteristics of Cereal Carbohydrates after Processing and Digestion

Different extraction, purification and digestion methods were used to investigate the molecular properties of carbohydrates in arabinoxylan and β-glucan concentrates, dietary fiber (DF) rich breads and ileum content of bread fed pigs. The breads studied were: a low DF wheat bread (WF), whole meal rye bread (GR), rye bread with kernels (RK), wheat bread supplemented with wheat arabinoxylan concentrate (AX) and wheat bread supplemented with oat β-glucan concentrate (BG). The weight average molecular weight (M_w) of extractable carbohydrates in β-glucan concentrate decreased eight-fold after inclusion in the BG bread when exposed to in vitro digestion, while the M_w of purified extractable carbohydrates in AX bread was reduced two-fold, and remained almost unaffected until reaching the terminal ileum of pigs. Similarly, the M_w of purified extractable carbohydrates in GR and RK bread was not significantly changed in the ileum. The AX bread resulted in the highest concentration of dissolved arabinoxylan in the ileum among all the breads that caused a substantial increased in ileal AX viscosity. Nevertheless, for none of the breads, the M_w of extractable carbohydrates was related neither to the bread extract nor ileal viscosity.     

Distance field computation for geological slab surface data sets

The three-dimensional shapes of tectonic plates that sink into the Earth’s mantle (slabs) are the starting point for a range of geoscience studies, from determining the forces driving the motion of tectonic plates, to potential seismic and tsunami hazards, to the sources of magmas beneath active volcanos. For many of these applications finite element methods are used to model the deformation or fluid flow, and therefore the input model parameters, such as feature geometries, temperature or viscosity, must be defined with respect to a smooth, continuous distance field around the slab. In this paper we present a framework for processing sparse and noisy seismic data (earthquake locations), defining the shape of the slab and computing a continuous distance function on a mesh with variable node spacing. Due to the inhomogeneous volumetric distribution of earthquakes within the slab and significant inaccuracies in the locations of earthquakes occurring hundreds of kilometers below the Earth’s surface, the seismicity data set is extremely noisy and incomplete. Therefore, the preprocessing is the major part of the framework consisting of several steps including a point based smoothing procedure, a powerful method to use other observational constraints on slab location (e.g., seismic tomography or geologic history) to extend of the slab shape beyond earthquake data set and continuous resampling using moving least squares method. For the preprocessed point data we introduce approaches for finding the three-dimensional boundary of the slab and a subdivision of the slab into quadric implicit polynomials. The resulting distance field is then compiled from distances to the piecewise continuous approximation of the slab and distances to slab boundary.