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Abstract

With reference to the situation experienced in several Polish collieries where the risk of occurrence of gas-geodynamic phenomena is increasing and decisions to start the mining activities need to take numerous constraints associated with previous mining into account, this paper addresses certain geo-mechanical aspects of longwall mining in the zones of excavation edge interactions giving rise to major changes in the conditions of the deposit and rock strata, as a consequence of previous mining operations in adjacent coalbeds. Starting from the analytical description of displacements and stresses in the proximity of longwall mining systems, the paper summarizes the results of model tests and investiga-tions of the influence that the excavation edge has on the behavior and structural continuity of a portion of the coal body in the coalbed beneath or above an old excavation. Based on selected nonlinear functions emulating the presence of edges in the rock strata, a comparative study is carried out by investigating two opposite directions of workface advance, from the gob area towards the coal body and from the coal body towards the gobs. The discussion of the results relies on the analysis of roof deformation and the concentration factor of the vertical stress component at the workface front.
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Abstract

O swojej pracy i życiu opowiada małżeństwo naukowców prof. dr hab. inż. Przemysław Perlikowski, który zajmuje się inżynierią mechaniczną oraz dr hab. n. med. Renata Perlikowska, której specjalnością są peptydy opioidowe mające zastosowanie w medycynie.
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Abstract

This study aims to design a novel air cleaning facility which conforms to the current situation in China, and moreover can satisfy our demand on air purification under the condition of poor air quality, as well as discuss the development means of a prototype product. Air conditions in the operating room of a hospital were measured as the research subject of this study. First, a suitable turbulence model and boundary conditions were selected and computational fluid dynamics (CFD) software was used to simulate indoor air distribution. The analysis and comparison of the simulation results suggested that increasing the area of air supply outlets and the number of return air inlets would not only increase the area of unidirectional flow region in main flow region, but also avoid an indoor vortex and turbulivity of the operating area. Based on the summary of heat and humidity management methods, the system operation mode and relevant parameter technologies as well as the characteristics of the thermal-humidity load of the operating room were analyzed and compiled. According to the load value and parameters of indoor design obtained after our calculations, the airflow distribution of purifying the air-conditioning system in a clean operating room was designed and checked. The research results suggested that the application of a secondary return air system in the summer could reduce energy consumption and be consistent with the concept of primary humidity control. This study analyzed the feasibility and energy conservation properties of cleaning air-conditioning technology in operating rooms, proposed some solutions to the problem, and performed a feasible simulation, which provides a reference for practical engineering.
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