Non-dismantling control possibilities of distrubuted systems measuring channels in-situ operation place

In this work the structure of a multi-value and multi-range voltage measure with automatic correction of the additive error component is proposed and analyzed. Their used possibilities for the calibration of measuring channels of distributed systems on-situ exploitation are discussed. It is shown that the limit value of the uncorrected additive error component for modern elements will be several tens of nanovolts

6th century BC glass beads from Southern Ukraine: raw materials and technology

The aim of this study is to establish the nature of the remains of the glass industry found at the ancient Greek archaeological site on the Yahorlyk bay shore (North Black Sea region, Ukraine), dated to the 7th-5th centuries BCE. A multi-analytical, non-destructive approach that compares the chemical and mineralogical composition of glass fragments with that of sand collected in the vicinity of the archaeological site was used in order to determine the local or non-local origin of the glass artefacts. To this end, a comprehensive characterization of all the materials was performed by means of XRF, VP-SEM-EDS, LA-ICP-MS and XRD. In parallel, an attempt was made to reconstruct the manufacturing process of the glass objects with an emphasis on the recipe used and how the colour was achieved. The results will contribute important new information to the literature concerning glass circulation in the Black Sea region; Resumo: Com esta dissertação pretendeu-se determinar a natureza dos objetos remanescentes da indústria vidreira encontrada no sítio arqueológico localizado na costa da baía de Yahorlyk (região do Mar Negro Norte, Ucrânia), datado dos séculos VII a V a.C. e com ocupação Grega. Neste estudo foi usada uma abordagem multi-analítica e não-destrutiva, que permitiu comparar a composição química e mineralógica dos fragmentos de vidro com a da areia recolhida nas proximidades do sítio arqueológico, a fim de determinar a origem local ou não-local dos artefactos de vidro. Para este fim, os materiais foram caracterizados por FRX, MEV-EDS, LA-ICP-MS e DRX. Paralelamente, tentou-se compreender a técnica de fabrico dos objetos de vidro, dando particular ênfase ao processo de manufatura usado assim como na forma de obtenção da cor. Os resultados contribuirão com novas informações sobre a circulação de artefactos vítreos na região do Mar Negro

Simualtion of electrochemical systems by analyzing impedance spectra

In this work is carried out simulation of electrochemical system: primary transducer - object by analyzing impedance spectra in different frequency ranges and for different concentrations of these objects. On the basis of modeling, the electrochemical processes occurring in the investigated system are interpreted using elements of the higher hierarchical level of construction of bipolar units

Експериментальні дослідження ефективності температурних каналів для сонячних енергосистем

The methods to improve the thermal test equipment and determine the efficiency of solar collectors are proposed. To improve the performance specifications of such equipment, it is proposed to use highly sensitive semiconductor sensors. Based on experimental studies, planar transistors are chosen and sensors that can be used in temperature channels of devices for solar system studies are designed. Series connection of several transistor diodes enables an increase in sensitivity while reducing technological variations and simplifying secondary devices.The experimental studies have shown that the maximum temperature characteristics variation of the nine studied sensors does not exceed ±0.06 °С throughout the measuring range of 0 °С to +80 °С.The structure of a digital temperature difference meter with the studied sensors is designed. The temperature difference meter circuit is based on two current-to-voltage converters, in the feedback of which temperature sensors are enabled. By using a single reference voltage source, the same currents will flow through the sensors. The output signals of both converters are equal to voltage drops on the sensors and are fed to the differential inputs of the ADC, which provides a source code proportional to the measured temperature difference. The meter calibration at any temperature in the measuring range while ensuring the temperature uniformity of both sensors is proposed. After calibration, the estimated error value of the temperature difference meter does not exceed ±0.1 °С throughout the measuring range.The calibration method of precision digital thermometers with the designed sensors in two temperature points is proposed. At 0 °С, the thermometer additive error is determined, which is later used as a correction to all measuring results. The multiplier factor value is expedient to determine near the maximum measured temperature as the ratio of the nominal and the resulting values of the code that matches the calibration temperature. A method for adjusting a nonlinear error component in the whole measuring range is developed. It is based on determining the parameters of sensors approximating dependencies using experimental data. The logarithmic approximation temperature dependence of semiconductor sensors, whose value is equal to zero at both calibration temperature values is proposed. It is shown that this approximation dependence can be easily implemented in the modern microcontrollers base. After calibration, the acceptable error limit of digital thermometers in the measuring range from 0 °С to 100 °С does not exceed ±0.1 °С.Разработаны предложения относительно усовершенствования оборудования для тепловых испытаний солнечных коллекторов. Установлено, что в радиометрах с электрическим замещением целесообразно использовать высокочувствительные полупроводниковые сенсоры, в частности исследуемые типы транзисторов. Разработана структура цифрового измерителя разности температур и методика калибровки таких термометров в двух температурных точках. Предложена методика корректировки нелинейной составляющей погрешности во всем измерительном диапазонеРозроблено пропозиції щодо вдосконалення обладнання для теплових випробувань сонячних колекторів. Встановлено, що в радіометрах з електричним заміщенням доцільно використовувати високочутливі напівпровідникові сенсори, зокрема досліджувані типи транзисторів. Розроблено структуру цифрового вимірювача різниці температур та методику калібрування таких термометрів у двох температурних точках. Запропоновано методику коригування нелінійної складової похибки у всьому вимірювальному діапазон

The effect of Mexidol on magnesium-calcium balance and endothelial dysfunction in operational stress

<p>The aim of the study: to study the effect of mexidol content of ionized calcium and magnesium in erythrocytes and the number of circulating endothelial cells in patients undergoing surgery in the maxillofacial area. Material and methods. The intracellular concentration of calcium and magnesium was measured before the operation, in one, three and five days after the surgery with the help of cytochemical method. Mexidol (100mg) was administered intravenously as a single addition to the standard premedication. Results. After surgery, the intracellular calcium and magnesium content increased. After 24 hours, the magnesium level began to decline, and the calcium content in erythrocytes continued to grow. On day 5, the magnesium concentration in erythrocytes decreased below the initial level, and calcium levels remained significantly elevated. Number of endothelial cells in the blood increased immediately after surgery and magnesium-calcium balance and limits endothelial dysfunction. Mexidol continued growing, reaching a peak on day 5 after surgery. When using mexidol decreased levels of calcium and magnesium levels help prevent falls on the 5th day after surgery, decreased the number of circulating endothelial cells. Conclusion. Mexidol prevents postoperative magnesium violation.</p