Excitability of Vascular Smooth Muscle

Regulation of pressure and local blood flow occurs at the level of resistance arteries and arterioles. Under physiological conditions, these small vessels exist in a state of partial constriction, termed myogenic tone. Myogenic tone is considered to be an intrinsic property of arteriolar smooth muscle cells, which membranes depolarize in response to increase in the intraluminal pressure. Oscillations of membrane potential in smooth muscles are mediated by the activity of voltage-gated L-type Ca2+ channels, which provide an influx of Ca2+ to activate various voltage-gated and Ca2+-sensitive channels of smooth muscle cells and to initiate endothelial Ca2+ signaling needed for vasodilation. Although a relationship between change in membrane potential and myogenic response is considered to be universal throughout various smooth muscle tissues, it may be regulated differently based on autoregulatory responses and channels expression. Here we review electrophysiological signature of arteriolar smooth muscle in various tissues, with an emphases and specific examples of the excitability of 4th order arterioles isolated from skeletal muscle

The Chinese diaspora and security issues in Southeast Asia

В статье рассматривается положение китайских диаспор в Юго-Восточной Азии и их влияние на формирование мирной обстановки в странах региона. Раскрыты основные виды конфликтов и определены факторы, формирующие комплекс противоречий между сообществами зарубежных китайцев в Юго-Восточной Азии и местным населением на государственном и муниципальном уровнях.The article deals with the position of the Chinese diaspora in Southeast Asia and their effect on the formation of a peaceful environment in the region. The author reveals the main types of conflicts and determine the factors that shape the complex contradictions between communities of overseas Chinese in Southeast Asia and the local population on the state and municipal levels

Development of engineering solutions for air drilling at Dulisminsk oilfield, Irkutsk oblast

The article presents the analysis of disastrous mud loss achieved during casing at Dulisminsk oil and gas condensate field (DOGCF) and comparative evaluation of geological structure of DOGCF and Naryksko-Ostashkinsk area of Kemerovo oblast, where the same problem was solved successfully. On the basis of the analysis, an engineering solution is proposed to prevent mud loss in the conditions of DOGCF

Experimental research of drilling mud influence on mud motor mechanical rubber components

The paper describes the experimental research of drilling mud influence on engineering parameters of mud motor mechanical rubber components. It is believed to be urgent due to increase in using mud motors in oil and gas well construction now, and, consequently, the issue of increasing their exploitation is becoming current. The development test results of elastomer IRP-1226 dependent on the mud type (alkaline, hydrocarbon or salt-saturated ones) and the temperature are shown in the paper. It is proved that the type of drilling mud and the temperature in bottom-hole zone have an influence on wear of mud motors elastomers

Methods of study in the characteristics of elastomers' samples of mud motors at modeling the conditions of their operation

The paper describes the development of the methods of experimental research on rubber elastomers parameters of mud motors at modeling the conditions of their operation. The specific features of mud motors operation as well as main aggressive agents affecting the state and parameters of elastomers, such as drilling mud type, ambient temperature, and mechanical action of the rotor on the plate of the stator are shown in the paper. Due to described agents, new methods of investigations and new units of experimental bed are developed

Impact of hydrocarbon drilling mud on mud motor elastomers at different temperatures

The paper describes the experimental research of hydrocarbon drilling mud impact on engineering parameters of mud motor elastomer samples. It is believed to be urgent due to an increase in using mud motors in oil and gas well construction now, and the issue of intense exploitation is currently topical. The test results of elastomer IRP- 1226 dependent on the temperature are shown in the paper. It is proved that the hydrocarbon drilling muds have a significant impact on wearing of mud motors elastomers under the condition of a temperature increase

The diagram development for Computer Added Control and Monitoring system of drilling

The paper is concerned with the first stage of the extensive research aimed at developing design-automation system and well drilling process control. The proposed system is going to have some advantages over modern analogues, such as economic analysis at all levels, active engineering staff feedback, precedent-related principle for recommendations, etc. It will essentially reduce the risk of human errors and also optimize the well construction process from design to commissioning. The paper considers the results of the first design stage in a form of flow diagrams

Methods to ensure optimal off-bottom and drill bit distance under pellet impact drilling

The paper describes pellet impact drilling which could be used to increase the drilling speed and the rate of penetration when drilling hard rock for various purposes. Pellet impact drilling implies rock destruction by metal pellets with high kinetic energy in the immediate vicinity of the earth formation encountered. The pellets are circulated in the bottom hole by a high velocity fluid jet, which is the principle component of the ejector pellet impact drill bit. The paper presents the survey of methods ensuring an optimal off-bottom and a drill bit distance. The analysis of methods shows that the issue is topical and requires further research