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Abstract

Electric energy meters are designed to account energy under sinusoidal and nonsinusoidal conditions, because both, old and new standards for energy meters require testing their accuracy under different conditions. The latest EN 50470 standard increases the range of meter testing under nonsinusoidal conditions, introducing new shapes of test signals such as the phase fired waveform or the burst fired waveform. This paper discusses calibration problems of electronic revenue energy meters for direct connection and for connection through current transformers, and it proposes a new calibration procedure which reproduces normal operating conditions better: three-phase configurations of measurement systems, load range during meter testing or shapes of test signals. Recently, modern Electrical Power Standards, also known as Power Calibrators, enable automatic testing of various types of electrical devices, including electricity meters in their normal operating conditions. This article presents examples of single and multi position fully automatic test systems, which employ Power/Energy Calibrator from Poland as the precision source with programmed waveforms of three phase voltages up to 560 V and currents up to 120 A conforming to EN 50470, or with random waveforms generated by PC software random wave generator. Measurement uncertainty of the energy meters under different nonsinusoidal conditions using a test system with reference to accuracy of the power calibrator or to the reference meter, are discussed. Comparative analysis of test results for different shapes of voltage and current signals is presented in the conclusions of this paper.
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Abstract

The paper presents an analysis of factors influencing the accuracy of reproduction of geometry of the vertebrae and the intervertebral disc of the lumbar motion segment for the purpose of designing of an intervertebral disc endoprosthesis. In order to increase the functionality of the new type of endoprostheses by a better adjustment of their structure to the patient’s anatomical features, specialist software was used allowing the processing of the projections of the diagnosed structures. Recommended minimum values of projection features were determined in order to ensure an effective processing of the scanned structures as well as other factors affecting the quality of the reproduction of 3D model geometries. Also, there were generated 3D models of the L4-L5 section. For the final development of geometric models for disc and vertebrae L4 and L5 there has been used smoothing procedure by cubic free curves with the NURBS technique. This allows accurate reproduction of the geometry for the purposes of identification of a spatial shape of the surface of the vertebrae and the vertebral disc and use of the model for designing of a new endoprosthesis, as well as conducting strength tests with the use of finite elements method.
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Abstract

Purpose: The purpose of this research is to defi ne the total number of septa and the total number of antra in the sphenoid sinuses (created as a result of the presence of additional septa), as well as the relation between the number of the septa and their location in the adult population. Materials and Methods: The study was conducted as a retrospective analysis of the computed tomography (CT) scans of the paranasal sinuses of 296 patients (147 females and 149 males), who did not present any pathology in the sphenoid sinuses. The CT scans of the paranasal sinuses were done with the spiral CT scanner (Siemens Somatom Sensation 16) by using a standard procedure, in the option Siemens CARE Dose 4D, without using any contrast medium. After obtaining the transverse planes, the frontal and sagittal planes were created using secondary reconstruction tool (multiplans reconstruction — MPR). Results: The analysis of the obtained images in the transverse plane and secondary CT reconstructions has shown the presence of only one sphenoid septum (main septum — MS) in 21.96% of the patients, which divided the sphenoid sinus into two sphenoid antra. In 78.04% of the patients, there were more than one sphenoid septa present in the posterior part of the sphenoid sinuses, hence there were additional septa (AS) present. One AS was present in 22.97% of the patients. The most common variant — two AS — was found in 32.09% of the cases. The presence of more than two AS was found in the following number of patients: three AS in 9.8%, four AS in 7.09%, five AS in 1.69%, six AS in 3.04% and seven AS in 1.01%. Th e rarest variant was the presence of more than seven AS: eight AS in 0.34% and nine AS also in 0.34%. Th ere were no sphenoid sinuses that would have more than nine AS in the researched material. Conclusions: Due to the high incidence of the anatomical variants of the paranasal sinuses, a CT scan is recommended in all patients before a planned surgery in order to avoid the potential complications that might arise as a result of the complicated structure of the paranasal sinuses.
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Abstract

The aim of the study is to present cycling as an active form of tourism in the context of the motivation of people cultivating it – in particular residents of the Municipality of Radom. The work indicates the essence and importance of cycling tourism, taking into account its types and infrastructure. Factors and trends influencing the development of cycling tourism – promoting a healthy lifestyle were discussed. Also presented are the results of research on the motivation of moving residents of the Municipality of Radom using the bike in individual age groups.
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