Fitting the grain orientation distribution of a polycrystalline material conditioned on a Laguerre tessellation

The description of distributions related to grain microstructure helps physicists to understand the processes in materials and their properties. This paper presents a general statistical methodology for the analysis of crystallographic orientations of grains in a 3D Laguerre tessellation dataset which represents the microstructure of a polycrystalline material. We introduce complex stochastic models which may substitute expensive laboratory experiments: conditional on the Laguerre tessellation, we suggest interaction models for the distribution of cubic crystal lattice orientations, where the interaction is between pairs of orientations for neighbouring grains in the tessellation. We discuss parameter estimation and model comparison methods based on maximum pseudolikelihood as well as graphical procedures for model checking using simulations. Our methodology is applied for analysing a dataset representing a nickel-titanium shape memory alloy

Analysis of collision possibility in auxiliary railway transportation

Transport kopalniany materiałów i przewóz osób w podziemnych wyrobiskach górniczych prowadzony jest z wykorzystaniem kopalnianej kolei podziemnej, kolejek spągowych oraz kolejek podwieszonych. Zwiększające się gabaryty i masy transportowanych maszyn i urządzeń wymagają projektowania systemów transportowych w oparciu o analizy istniejących tras, pod względem możliwości wystąpienia kolizji z obudową oraz wyposażeniem wyrobisk korytarzowych, co wiąże się również z właściwym doborem zastosowanych urządzeń transportowych. W artykule przedstawiono komputerową metodę analizy możliwości wystąpienia kolizji, dla kolejek spągowych oraz podwieszonych, za pomocą autorskiego oprogramowania, opracowanego w ITG KOMAG. Omówiono założenia metody i jej implementację w środowisku programu AutoCAD. Przedstawiono integrację opracowanego oprogramowania z systemem Safe Trans Design (STD), wdrożonym w kopalniach JSW S.A. Zaprezentowano przykłady analiz kolizyjności w przypadku transportu sekcji obudowy zmechanizowanej kolejką podwieszoną.Mine transportation of materials and people in underground workings is performed by the use of mine railway system, floor-mounted railway and suspended monorail. The increasing size and weight of the transported machines and equipment require planning the transportation system based on analyses of the existing transportation routes as regards the possibility of collision with roof support and with roadway equipment to select properly transportation machines. Computer method of collision analysis for floor-mounted railway and suspended monorail with the use of the author’s computer program, developed at KOMAG, is presented. Assumption of the method and its implementation in AutoCAD software environment is discussed. Integration of the developed computer program with Safe Trans Design (STD) system, implemented in JSW S.A. mines, is presented. Examples of collision analyses in the case of transportation of powered roof support by suspended monorails are described

The influence of 9-day trekking in the Alps on the level of oxidative stress parameters and blood parameters in native lowlanders

Background. The stimuli acting on a person in a high mountain environment (such as hypobaric hypoxia with subsequent reoxygenation, physical exercise) can significantly increase oxidative stress, stimulate erythropoiesis, lead to changes in the blood count and participate in the development of altitude sickness. Objective. The aim was to investigate changes in haematological parameters, indicators of oxidative stress (malondialdehyde – MDA) and antioxidant defences: catalase (CAT), superoxide dismutase (SOD), and total antioxidant status (TAS) in the plasma of young, healthy people after a 9-day expedition in the Alps. Materials and method. A total of 5 patients (4 men and 1 woman), members of the Wrocław Mountaineering Club, aged 24–26 years. Collection of blood samples was carried out immediately before departure and 3 days after the end of exposure to high-altitude conditions. During the expedition, the subjects were exposed to heights: 2,050–4,165 m.a.s.l., and exercise associated with climbing. Results. Trekking in the Alps neither caused significant changes in the parameters of red blood cells nor increased the level of oxidative stress parameters in plasma. CAT activity increased, the ratio of SOD / CAT decreased. There was also a decrease in the total number of leukocytes, mainly monocytes and basophils. Conclusions. 9-day exposure to high-altitude conditions is not a substantial burden for the organism of young, physically active people. The increase in antioxidant capacity is sufficient to stop oxidative processes, which are severe in these conditions, and to prevent the occurrence of significant oxidative stress. Discontinuation of exposure to allergens and dust pollution clears the airways, which is indicated by the reduction in the number of monocytes and basophils

Effect of treatment with N-acetylcysteine on non-enzymatic antioxidant reserves and lipid peroxidation in workers exposed to lead

There are no published studies examining the effects of N-acetylcysteine (NAC) administration on the non-enzymatic defence systems in humans exposed to lead. In view of this, it was decided to measure the levels of uric acid (UA), albumin, bilirubin and alpha-tocopherol before and after treatment with NAC. An estimation was also made of the degree of oxidative stress by measuring the ferric reducing ability of plasma (FRAP), the levels of conjugated dienes (CD) and lipid hydroperoxides (LHP). Male employees who worked with lead were randomized into two groups. The first group included workers who were not administered any drugs (n=49), while the second group (n=122) consisted of workers who were treated with NAC at three different doses (200 mg, 400 mg and 800 mg) for 12 weeks. The administration of NAC (400 mg, 800 mg) resulted in significant decreases in the LHP levels. Similarly, a strong tendency toward lower levels of CD was observed in the same groups. The UA levels were significantly lower only in the group receiving the 200 mg dose of NAC. However, the alpha-tocopherol levels were significantly elevated after treatment with NAC (400 mg, 800 mg). NAC administration did not significantly affect the levels of bilirubin and albumin, but a tendency toward higher values was observed for FRAP. NAC reduced the extent of lipid peroxidation in a dose-dependent manner. Elevated concentrations of alpha-tocopherol may have enhanced the beneficial effects of NAC. Treatment with NAC may contribute to the restoration of non-enzymatic antioxidant reserves when administered to lead-exposed workers

Dissociation or cyclization : options for a triad of radicals released from oxime carbamates

A set of oxime carbamates, having N-alkyl- and N,N-dialkyl-substituents, was prepared via carbonyldiimidazole intermediates. It was shown by EPR spectroscopy that they underwent clean homolysis of their NO bonds on UV photolysis. During photolysis of acetophenone O-allylcarbamoyl oxime the corresponding oxazolidin-2-onylmethyl radical was detected by EPR spectroscopy, providing the first evidence that N-mono-substituted carbamoyloxyl radicals can hold their structural integrity. N,N-Di-substituted carbamoyloxyl radicals dissociated rapidly at the lowest accessible temperatures. Above room temperature both types of oxime carbamate acted as selective new precursors for aminyl and iminyl radicals. Rate parameters were measured for 5-exo-cyclization of N-benzyl-N-pent-4-enylaminyl radicals; the rate constant was smaller than for C-centered and O-centered analogs. Oxime carbamates derived from the volatile diethylamine afforded aryl-iminyl radicals that proved convenient for phenanthridine preparations.Publisher PDFPeer reviewe