HPC in Computational Micromechanics of Composite Materials

Proceedings of: Second International Workshop on Sustainable Ultrascale Computing Systems (NESUS 2015). Krakow (Poland), September 10-11, 2015.This work was supported by the European Regional Development Fund in the IT4Innovations Centre of Excellence project (CZ.1.05/1.1.00/02.0070) and the COST NESUS project with an additional CZ MEYS LD15105 support

Topographic inspection as a method of weld joint diagnostic

U radu se demonstrira topografsko ispitivanje u specifičnom kontekstu triju vrsta inspekcijskih metoda zavara od austenitnog nehrđajučeg željeza. Vizualna i metrološka kontrola provedena je tijekom ispitivanja zavarivanja TIG postupkom, primjenom ne-destruktivnih metoda: rendgensko ispitivanje, kompjuterizirana tomografija i profilometrija površine. Rad je reakcija na nedostatak informacija, posebice u području ne-destruktivnih metoda prikladnih za široku primjenu u praksi. U radu se prezentiraju prednosti i nedostaci analiziranih dijagnostičkih metoda i klasifikacija uobičajenih i specifičnih mana zavarenog spoja. Najvažnija neispravnost u praktičnim primjenama kod određivanja pouzdanosti zavarenog spoja su pukotine. Ova vrsta dijagnoze zasnovana je na dobivenim podacima o promatranom anizotropskom i nehomogenom volumenu u dijelu zavara pod utjecajem topline.The paper demonstrates a topographic inspection in the specific context of three kinds of inspection methods of austenitic stainless steel welds. Visual and metrological inspection was analysed during tungsten inert gas (TIG) welding tests, showing the non-destructive techniques: X-ray, computed tomography, and surface profilometry. The article is a response to the lack of information, especially in the area of non-destructive techniques suitable for wide practical application. The Paper presents advantages and drawbacks of the analysed diagnostic methods and a classification of conventional and specific welded joint flaws. The most important defect in practical applications determining reliability of a welded joint is cracks. This kind of diagnostic is based on the obtained information about anisotropic and inhomogeneous volume under consideration in the heat-affected zone of a weld

Novel CHK1 inhibitor MU380 exhibits significant single-agent activity in TP53-mutated chronic lymphocytic leukemia cells

Introduction of small-molecule inhibitors of B-cell receptor signaling and BCL2 protein significantly improves therapeutic options in chronic lymphocytic leukemia. However, some patients suffer from adverse effects mandating treatment discontinuation, and cases with TP53 defects more frequently experience early progression of the disease. Development of alternative therapeutic approaches is, therefore, of critical importance. Here we report details of the anti-chronic lymphocytic leukemia single-agent activity of MU380, our recently identified potent, selective, and metabolically robust inhibitor of checkpoint kinase 1. We also describe a newly developed enantioselective synthesis of MU380, which allows preparation of gram quantities of the substance. Checkpoint kinase 1 is a master regulator of replication operating primarily in intra-S and G2/M cell cycle checkpoints. Initially tested in leukemia and lymphoma cell lines, MU380 significantly potentiated efficacy of gemcitabine, a clinically used inducer of replication stress. Moreover, MU380 manifested substantial single-agent activity in both TP53-wild type and TP53-mutated leukemia and lymphoma cell lines. In chronic lymphocytic leukemia-derived cell lines MEC-1, MEC-2 (both TP53-mut), and OSU-CLL (TP53-wt) the inhibitor impaired cell cycle progression and induced apoptosis. In primary clinical samples, MU380 used as a single-agent noticeably reduced the viability of unstimulated chronic lymphocytic leukemia cells as well as those induced to proliferate by anti-CD40/IL-4 stimuli. In both cases, effects were comparable in samples harboring p53 pathway dysfunction (TP53 mutations or ATM mutations) and TP53-wt/ATM-wt cells. Lastly, MU380 also exhibited significant in vivo activity in a xenotransplant mouse model (immunodeficient strain NOD-scid IL2Rγnull) where it efficiently suppressed growth of subcutaneous tumors generated from MEC-1 cells

The Comet Interceptor Mission

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule

Experimental approach to measure stress and stress changes in rock ahead of longwall mining faces in Czech coal mines

The measurement and monitoring of stress in rock mass are very important tasks in mining geomechanics. With increasing mining depth and worsening of the geological and mining conditions, a suitable method to determine and monitor rock stress and stress changes due to longwall coal mining is needed. Detailed knowledge of the stress state in rock mass is very useful when designing safe mining activity, especially in rockburst areas. The paper presents a brief description of the Compact Conical-ended Borehole Monitoring (CCBM) method for rock stress evaluation and the technical details of this innovative technology. The second part of the contribution evaluates and discusses initial results and experience obtained from the use of CCBM equipment for determination and observation of mining-induced stresses during mining of selected longwall panels in the conditions of the deep coal mines of the Upper Silesian Coal Basin

Flow Field Analysis Inside and at the Outlet of the Abrasive Head

This paper focuses on the investigation of a multiphase flow of water, air, and abrasive particles inside and at the outlet of the abrasive head with the help of computational fluid dynamics calculations and measurements. A standard abrasive head with a water nozzle hole diameter of 0.33 mm (0.013”) and an abrasive nozzle cylindrical hole diameter of 1.02 mm (0.04”) were used for numerical modelling and practical testing. The computed tomography provided an exact 3D geometrical model of the cutting head that was used for the creation of the model. Velocity fields of abrasive particles at the outlet of the abrasive head were measured and analysed using particle tracking velocimetry and, consequently, compared with the calculated results. The calculation model took the distribution of the abrasive particle diameters with the help of the Rosin-Rammler function in intervals of diameters from 150 to 400 mm. In the present study, four levels of water pressure (105, 194, 302, 406 MPa) and four levels of abrasive mass flow rate (100, 200, 300, 400 kg/min) were combined. The values of water pressures and hydraulic powers measured at the abrasive head inlet were used as boundary conditions for numerical modelling. The hydraulic characteristics of the water jet were created from the measured and calculated data. The calculated pressure distribution in the cylindrical part of the abrasive nozzle was compared with studies by other authors. The details of the experiments and calculations are presented in this paper

Numerical modelling on the stability of an underground research facility excavation in Czech Republic

ABSTRACT: A new Underground Research Facility (URF) is planned to be constructed in the Rožná Mine, Czech Republic. It is essential to evaluate the feasibility of the current excavation design before the start of the excavation. Numerical simulation using the software FLAC3D was adopted to investigate the stability or the strength-stress ratio of the URF. Laboratory tensile strength and uniaxial compressive strength tests on the rock specimens at various inclinations of the weak planes combined with the Geological Strength Index (GSI) system provide reliable deformation and strength input parameters for the explicit continuum model. The well-known modified Hoek-Brown constitutive model was employed for the numerical evaluation of the URF stability. In situ three-dimensional stress tensors were measured from the field and applied to the model boundaries. Displacement/convergence and distribution patterns of the stress state and strength-stress ratio were analysed. It was found that the current URF layout is on the safe side and the total displacement is minor and acceptable. Locations with potentially low strength-stress ratios were mainly around the roadway-chamber intersections. The current study can provide a valuable reference to similar numerical works since such large-scale numerical simulations are rare, due to the complexity and the time-consuming nature of the study

Stress state monitoring in the surroundings of the roadway ahead of longwall mining

Accurate knowledge of the stress-strain state of rock mass, not only in their vicinity but also in the wide surroundings of mine workings, is absolutely critical for precise support designing. Investigation of the rock stress is usually carried out by interpretation of the rock mass deformation processes, which can be relatively precisely observed and measured. In order to verify the stress state of the rock mass and changes in it induced by longwall mining, monitoring of changes in the rock mass stress in connection with the mine out of the longwall No. 371 202 was carried out. The seam extracted by monitored longwall has a thickness of approximately 2 m at a depth about 1100 m and lies within the Czech part of the Upper Silesian Coal Basin. Interpretation of the initial rock mass stress tensor and verification of its changes during longwall mining were the aims of this stress monitoring. A total of five probes were installed on the roof rocks of the main gate. Two compact conical-ended borehole overcoring probes were installed to obtain the pre-mining full stress tensor and afterwards three compact conical-ended borehole monitoring probes were installed to continuously monitor the stress state in the rock mass ahead of the advancing longwall. The monitored stress development contributes to our knowledge of stress distribution and its changes during excavation at great depth in multi-seam sedimentary deposits of the Upper Silesian Coal Basin

THE EFFECT OF THE SODIUM SULPHATE SOLUTION EXPOSURE ON PROPERTIES AND MECHANICAL RESISTANCE OF DIFFERENT KINDS OF RENDERS

The effect of 5% water solution of the sodium sulphate and the reference environment of distilled water on changes in mechanical resistance of the commercial dry render mixes was researched in the paper. The prism-shaped specimens cured 28 days in humid and stable conditions were immersed in water or sodium sulphate water solution. At chosen time, the particular specimens were collected, dried to constant mass, and subjected to tests. The maximum time of specimen exposure to moisture or salt action was 168 days. Within the performed experiments, length changes, mass gain, mechanical and basic properties were measured in order to reveal the effect of sulphate corrosion on researched materials. Additionally, pore size distribution measurement and X-Ray CT analysis for the most damaged render were done, in order to characterize the disruptive impact of sulphate solution on porous microstructure of lime-metakaolin-based render. The obtained data revealed the high capacity of porous space of the tested renders for salt storage. For shorter times of exposure to salt action, most of the studied renders exhibited improvement in mechanical resistance. On the other hand, after the full filling of the porous space, the evoked crystallization pressures led to the decrease in mechanical resistance and materials damage. However, one type of studied renders originally designed for restoration of salt laden masonry maintained its excellent mechanical properties even after 168 days of sulphate exposur

Effect of Testing Method Type and Specimen Size on Mode I Fracture Toughness of Kimachi Sandstone

Several testing methods have been proposed for evaluating the mode I fracture toughness of rocks. Since the fracture toughness evaluated from the different testing methods is generally not compared, what is still not wellknown is the effect of the testing method type on the fracture toughness. The effect of not only the testing method type but also the specimen size exists in the fracture toughness of rock materials. To clarify the effect of the testing method type and specimen size on the fracture toughness, many fracture toughness tests were performed in the previous experimental studies. However, the effect has not been elucidated because the number of the specimens is limited and the range of the specimen size is relatively small in the previous works. In this paper, firstly, three types of the fracture toughness test, the chevron bend (CB) test, semi-circular bend (SCB) test and straight notched disk bending (SNDB) test, were performed using Kimachi sandstone. Then, the SCB test was carried out using the same sandstone with various specimen sizes. As a result, the fracture toughness obtained from the CB and SCB tests were compatible each other. However, the SNDB tests estimated lower value of the fracture toughness than the others. From the results of the SCB tests with various specimen sizes, the fracture toughness increased with increasing radius. Based on the results, the effect of the specimen size on the fracture toughness and the differences of the fracture toughness obtained from the three testing methods were discussed