Torsion of a Non-Homogeneous Bar with Periodic Parallelepiped Inclusions: Analytical Expressions for Effective Shear Modulus

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Investigations of electromagnetic compatibility (EMC) of vehicles using open-area partially shielded test site model

The technological development in automotive industry that can be observed during the last several decades, especially during the last decade, causes that share of a vehicle electrical and electronic equipment constitutes over 30% of its total worth. This equipment essentially affects the safety of the driver and passengers as well as the driving comfort. In order to fulfill the growing requirements in the range of vehicles safety and reliability, conducting of numerous tests of the electrical/electronic equipment, including tests of electromagnetic compatibility, are necessary. As is known, EMC tests are expensive and difficult to reach, mainly due to the necessity of employing very expensive absorber-lined shielded test chambers. For this reason, there is a need for studying more accessible and less expensive EMC test methods, in particular, by using open-area partially shielded test sites (OAPSTS). In this paper, a model of OAPSTS is described. The model ensures that the tested vehicles are partially separated from the environment by shields attenuating electromagnetic waves. These shields have been made of electro-conductive fabrics worked out in Poland. Tests of vehicle immunity to electromagnetic radiation have been performed using the model of OAPSTS and the following vehicles: Skoda Octavia 1,8 and Daewoo Lanos 1,6. Estimation of parameters of the OAPSTS model for four variants of absorbe s placement has been worked out. The tests have been performed according to EU Directive 2004/104/EC and ECE UN Regulation No. 10

Methods of investigation of road vehicles in context of immunity to electromagnetic field

The question of testing of vehicles and their subassemblies, especially in the range of electrical and electronic equipment, is very extensive. The scope of the relevant tests becomes wider and the requirements, especially in the range of safety, reliability and comfort, become higher. Of particular significance, are in recent years, tests concerning electromagnetic compatibility (EMC) of whole vehicles and their subassemblies. A survey of basic standardized EMC test methods is presented in the paper. Moreover, an alternative test method of vehicle immunity worked out by authors is proposed. The method has been verified by using the open-area partially shielded test site (OAPSTS) model and compared with standardized methods contained in ECE UN Regulation No. 10 and EU Directive 2004/104/EC. Tests of vehicle immunity to electromagnetic field have been performed using the model of OAPSTS and the vehicles: Citroen-Berlingo, Skoda-Octavia and Daewoo-Lanos. Estimation of basic statistical parameters has also been worked out. The obtained results show that the proposed method is reliable and, on the other hand, it is more accessible and less expensive than the standardized methods in which employing of very expensive absorber-lined shielded test chambers is necessary. The present paper extends the results obtained in [6, 7]

A contibutionto evaluation of effective moduli of trabecular bone with rod-like microstructure

The homogenization theory has been applied to evaluation of effective moduli of a network of interconnected elastic rods modelling human cancellous bone. Numerical computations of the Young modulus, Poisson ratio and shear modulus have been carried out. The obtained results compare fevourably with available experimental data.Teorię homogenizacji zastosowano do wyznaczania efektywnych własności mechanicznych dla regularnej sieci elastycznych prętów modelujących kość gąbczastą. Wyznaczono numerycznie efektywne stałe techniczne: moduł Younga, współczynnik Poissona i moduł ścinania. Wyniki porównano z wynikami ekperymentalnymi uzyskując dobrą zgodność

Susceptibility testing of Aspergillus niger strains isolated from poultry to antifungal drugs - a comparative study of the disk diffusion, broth microdilution (M 38-A) and Etest methods

The aim of this study was to determine the sensitivity of Aspergillus niger strains isolated from birds to available antifungal drugs using different in vitro assays - classical disk diffusion, Etest® and broth microdilution NCCLS/CLSI M 38-A. The study material consisted of about 2.000 swabs and samples from different species of birds. A. niger (n=10) was accounted for 6.81% of the total pool of strains isolated. Determinations were made for 13 antifungal drugs using the disk diffusion method. The A. niger exhibited high susceptibility to enilconazole, terbinafine, voriconazole, tioconazole and ketoconazole, low susceptibility to clotrimazole, miconazole and nystatin, and resistance to amphotericin B, itraconazole, pimaricin, fluconazole and 5-fluorocytosine. Minimum inhibitory concentration (MIC) was determined for 9 antifungal drugs using the micromethod of duplicate serial dilutions in a liquid medium. A. niger strains were most susceptible to enilconazole and voriconazole. MIC ranged from 0.0625 to 0.5 μg/ml for enilconazole, with MIC90-0.5 μg/ml and MIC50-0.125 μg/ml. The corresponding values for voriconazole were 0.25-1 μg/ml, 1 μg/ml and 0.5 μg/ml. MIC for amphotericin B and terbinafine ranged from 0.5 to 4 μg/ml, while the values for the remaining drugs were highly varied. MIC was measured by the gradient diffusion method using Etest® for 5 antifungal drugs: amphotericin B, fluconazole, itraconazole, ketoconazole and voriconazole. By far the highest susceptibility was obtained in the case of voriconazole, with MIC ranging from 0.0625 to 1 μg/ml. MIC for amphotericin B ranged from 0.25 to 4 μg/ml, for itraconazole and ketoconazole ranging from 0.5 to 16 μg/ml. Methods available for this purpose are not always applicable in field conditions. The present results indicate that the Etest® technique, due to its high percentage of agreement with the M 38-A microdilution method, should find application in medical and veterinary practice

Application of the reiterated homogenization to determination of the effective moduli of compact bone

The aim of the paper is twofold. First, the available results of finding the effective macroscopic elastic moduli of a compact bone by using homogenization are surveyed. Secondly, it is shown that the proper framework for studying such organic materials with hierarchical microstructure is that of reiterated homogenization. T-convergance theory is applied to obtain the general formulae for the effective elastic moduli of a material with three structural levels.Cel pracy jest dwojaki: po pierwsze, przedstawiono podsumowanie dotychczasowych badań dotyczących wyznaczania współczynników sprężystości kości zbitej przy zastosowaniu metod homogenizacji. Po drugie, wykazano, że homogenizacja reiterowana stanowi odpowiednie narzędzie do badania takich materiałów organicznych o hierarchicznej mikrostrukturze. Zastosowano teorię T-zbieżności do wyprowadzenia ogólnych zależności opisujących efektywne współczynniki sprężyste materiału o trzech poziomach strukturalnych

Investigations of electric field strength (in EMC context) in chosen vehicles exposed to electromagnetic field

Fast development of electronics in recent years causes that the number of various kind electronic systems is still growing. This causes also that requirements concerning tests of electromagnetic compatibility (EMC) of whole vehicles as well as their electric/electronic subassemblies become more significant. In this paper, the most important requirements of international regulations in the range of EMC, i. e., ECE UN Regulation No. l0 and EU Directive 2004/104/EC, have been outlined. Moreover, results of investigations of electric field strength inside of three chosen vehicles have been presented. The tests have been performed, according to Directive 2004/104/EC, in an absorber-lined shielded chamber in thefrequency band 20MHz to 2000MHz and at the electric field strength in the reference point equal to 30V/m. The most important results of these investigations have been presented in the form of graphs of electric field strength distribution in various points of tested vehicles. Individual electric/electronic devices o f a vehicle are exposed to electromagnetic field with a very wide range of values of electric field strength - depending upon a device position in a vehicle, vehicle type and antenna polarization. Values of electric field strength inside of a vehicle may essentially exceed the values recommended by standards for immunity tests of electric/electronic subassemblies