The effect of the flux creep on the dissipation phenomena in tapes based on YBCO leading to the essentially non-linear voltage-current characteristic of a superconductor is discussed. The obtained ...results are compared to the calculations made in the framework of the existing thermal stabilization theory based on the model assuming a jump transition from a superconducting state to a normal one. It is shown that the latter model incorrectly describes the dissipation modes, first of all, in a temperature range up to the critical temperature of the superconductor. It is proved that the type of nonlinearity of voltage-current characteristics has a significant effect on the dissipative phenomena in tapes in this temperature region. As a result, the allowable currents stably flowing in superconducting tapes may be higher than a priory defined critical current determined for continuously rising voltage-current characteristic. Correspondingly, the critical current of high-Tc superconducting tapes, which is determined using continuously increasing voltage-current characteristic, has no physical meaning. Therefore, fundamentals of the thermal stabilization theory must consider the real temperature dependence of the dissipated energy in high-Tc superconducting tapes, which depends on the nonlinearity of their voltage-current characteristic.
The problems of ensuring the unity of non-invasive blood pressure measurements are considered. It is shown that the artery and surrounding tissues of the body serve as a means of comparing the values ...of blood pressure and air pressure in the cuff, and that the metrological traceability of measurement results to pressure standards only partially determines the reliability of these results. The potential possibilities of the surface pulse wave method in comparison with the Korotkov tone method are estimated.
Currently, there is a steady trend in increasing the volume of electrical equipment used in shipboard needs. At the same time, the primary electric power system of ships has long been based on an ...alternating current system. However, due to the changing and increasing requirements for the quality of the generated electric energy, the marine industry is developing more and more promising directions for the development of electrical systems. Thus, the most efficient and environmentally friendly shipboard power distribution system is the direct current (DC) system, which was adopted for a single power plant installation in combination with an alternating current network. This article discusses the current topic of electric propulsion on ships. The circuit design of a rowing electric installation with a distributed DC bus of a port icebreaker is considered. The expressions used to calculate the static load and build an electromagnetic model of a permanent magnet synchronous motor are given. Computer models for calculating the load in static and dynamic modes are shown.
Historical Sociology in Russia Romanovskiy, Nikolay V
Historická sociologie,
01/2018, Letnik:
10, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The author of this paper discusses the current state of historical sociology in Russia reflected in the respective section of the Sociological studies journal. After noting the potentialities of the ...discipline, the author summarizes the overall output of the 20 years’ long existence of this section. The basic preoccupation in the initial phase of the section’s existence was to get – and convey to readers – a clear understanding of the essence and functions of contemporary historical sociology (HS in the text below), to introduce its potentialities to the Russian sociologist audience. However, even today there are few regular contributors, authors tend to delve into minor issues, and even resort to long surpassed views on the discipline. A most urgent issue for Russian historical sociology today is, according to the author, to draw lessons from Russia’s recent centuries to understand the essence of Russia’s present as it is penetrated by its past: “Men make their own history, but they do not make it as they please; they do not make it under self-selected circumstances, but under the circumstances existing already, given and transmitted from the past. The tradition of all dead generations weighs like a nightmare on the brains of the living” (К. Маrx). This is the essence of the enigmas to be deciphered by historical sociologists. The author formulates some such enigmas (like the proverbial Russian rake repeatedly stepped-upon) observable in recent (as well as earlier) events in the country.
The relevance of numerical modeling of flood zones, characteristics of flow velocity field and marks of the river water levels is caused by the necessities of engineering practical work in ...development of mineral deposits, which are often situated in extremely difficult hydrographic conditions. In such conditions, the standard methods for calculating the mentioned characteristics do not allow us to achieve the desired result or do not take into account the whole variety of processes occurring in open flows, which are able to significantly affect the safe and trouble-free operation of the designed constructions. The aim of the work is to show how the objects affect the change in the shape of the estimated flood zone, the flow velocity field, and water levels in conditions of constraining impact on the living cross-section of the flow during the passage of water rate of rare exceedance probability (1 % occurrence) on the example of the Kondoma river site and both existing and planned hydraulic constructions (flood control dams) and construction sites located in its floodplain. Methods. Numerical modeling of flow characteristics (estimated flood zone, distribution of speeds and directions of flow, estimated water levels) on the site of the Kondoma river was conducted using the HEC-RAS (Hydrologic Engineering Center – River Analysis System) modeling system ver. 5.0.5. The model comprised three different scenarios. Scenario 1, the floodplain is relatively unbroken and there are no flood control dams and overburden dump; Scenario 2, there is a current flood control dam and overburden dump in the floodplain; Scenario 3, there are all the current objects mentioned in Scenario 2 and a designed flood control dam in the floodplain. The studied characteristics of the Kondoma river on the site under investigation were compared within all three implemented scenarios. Results. A simulation model for the passage of flood (1 % of the exceedance probability) according to three scenarios was developed for the site of the Kondoma river, with Scenario 1 taken as the control. The model was calibrated, and the roughness coefficients of the floodplain and channel were chosen as adequate to actual conditions. Numerical flow characteristics were obtained (the shape of the estimated flood zone, the distribution of speeds and directions of flow, and water levels and depths) according to the three mentioned scenarios and the conclusions were drawn concerning the extent of influence of the current structures in the left floodplain of the Kondoma river on the shape of free surface, and also the influence under condition of a new flood control dam appearing in the left floodplain was forecasted.
A synergistic extraction mixture containing chlorinated cobalt dicarbollide (CCD), carbamoylmethyl phosphine oxide (CMPO), and polyethylene glycol (PEG) has been investigated for the simultaneous ...recovery of cesium, strontium, lanthanides, and actinides from highly acidic media. The extraction properties of this mixture depend on the concentration ratio of the components. For recovery of all major radionuclides, the optimal ratio of CCD:PEG: CMPO = 5:1:1 should be used. The use of diphenyl-N,N-dibutylcarbamoylmethyl phosphine oxide and PEG-400 provides the most efficient recovery of cesium, strontium, lanthanides, and actinides. The possibility of using polyfluorinated ethers, esters, ketones, and sulfones as diluents was examined. Phenyltrifluoromethyl sulfone was the most suitable diluent tested. The use of this diluent allows good extraction properties, chemical and radiation stability, excellent explosion/fire-safety properties, and favorable hydrodynamic characteristics. The extraction of radionuclides from HNO
3
media by mixtures of CCD:PEG:CMPO in phenyltrifluoromethyl sulfone and the subsequent stripping behavior were evaluated.
Актуальность моделирования зон максимального разлива рек (зон затопления) при проведении инженерных изысканий для проектирования и строительства объектов хозяйственной деятельности, разработки ...проектов рекультивации нарушенных земель в зонах непосредственного влияния водных объектов связана с тем, что в современных условиях, при постоянно растущих требованиях к безопасности и бесперебойности работы проектируемых сооружений, существующие методики оценки опасности затопления не всегда дают удовлетворительный результат, чтобы в полной мере оценить наличие или отсутствие риска для проектируемого сооружения. Цель работы: анализ отечественного и зарубежного опыта моделирования зон затопления при максимальных уровнях воды рек для практического решения задач инженерного проектирования, оценка достоинств и недостатков основных подходов в практике изысканий, демонстрация возможностей одного из способов моделирования при решении конкретной инженерной задачи. Методы. При подготовке исходных данных для создания цифровой модели рельефа применялся метод анализа пространственных данных при помощи геоинформационных систем, для расчета максимальной зоны затопления – метод численного моделирования зоны затопления р. Иня и расположенной по левому берегу отработанной карьерной выемки в рамках производства работ по подготовке проекта рекультивации нарушенных земель. Численное моделирование выполнялось при помощи моделирующей системы HEC-RAS версии 5.0.5. Результаты. Произведен обзор существующей мировой и отечественной практики численного моделирования зон затопления рек при решении задач в области инженерного проектирования, приведена собственная модель расчетной зоны затопления на примере участка рекультивации «Моховское поле», показан пример оценки влияния на рекультивируемый объект при реализации наиболее негативного сценария (вероятное затопление карьерной выемки в период прохождения максимального расхода воды 1 % обеспеченности), описаны достоинства и недостатки применения разных подходов на практике.
Author of the paper reviews recent “making” of historical sociology in Russia. After summarizing key publications and reminding of the importance of the discipline, author states modest scope of the ...overall stock of these years. As it was, a basic assigment for smooth developoment of HS was to get a clear understanding of essence and functions of contemporary HS, to introduce its potentialities to sociologists’ audience. However, today there are only few sociologists regularly publishing papers on HS; and these authors tend to delve into incidental topics; even to return back to overcome views. A most urgent issue for Russian historical sociology today is seen, so the author, to learn from Russia’s historical course through recent centuries to understand the essence of Russia’s present as penetrated by its past: «Men make their own history, but they do not make it as they please; they do not make it under self-selected circumstances, but under circumstances existing already, given and transmitted from the past. The tradition of all dead generations weighs like a nightmare on the brains of the living» (К. Маrx). This is the essence of enigmas deciphered by historical sociologists. There are formulated some of such enigmas (or rather proverbial Russian rake) observable in recent (as well as in milennial) events in this country.
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