The Sundrun population of wild reindeer

The Sundrun wild reindeer (Rangifer tarandus) herd was recognized as a separate population during the 1950s. Since then, the herd has ranged over an area of approximately 180 000 km2 between the Indigirka and Kolyma Rivers in northeastern Yakutia. Population dynamics and movements were investigated between 1987 and 1997. During this period, the population estimates ranged from 25 000 to 45 000 reindeer, the sex ratio averaged 55 bulls:100 cows, and the percentage of calves in the herd ranged between 17% and 25%. The main routes of seasonal migrations, wintering areas, and the location of calving areas are discussed

Case of successful surgical correction of combined mitral defect and chronic atrial fibrillation at the elderly patient

<p><font><font>В статье представлены описание успешного случае процедуры cryomaze в сочетании с протезирование митрального клапана и трехстворчатого аннулопластики на пожилого пациента 71 лет. </font><font>Следующие особенности клинического случая следует отметить: хроническое фибрилляции предсердий в течение 20 лет, огромный левое предсердие из 348 мл. </font><font>Как известно из анамнеза, который закрылся митрального комиссуротомия было сделано 39 лет назад. </font><font>Это клинический случай демонстрирует возможность успешной коррекции сложных комбинированных патологий сердца даже в пожилом возрасте. </font><font>Кроме того, методика хирургической коррекции дисфункции митрального клапана в сочетании с мерцательной аритмией предусматривает обязательное устранение аритмии. </font><font>Тщательный диагностика и выбор оптимального хирургического вмешательства комбинированного сердечно-сосудистых заболеваний позволяет достичь хороших результатов даже у пожилых пациентов.</font></font></p

Method for direct identification of optimum modal values of dynamical systems

The synthesis method of a dynamic system by successive solutions of two systems of algebraic equations, variables that are characteristic polynomial coefficients and mechanical parameters of the system

Investigation of Stress-Strain State of the Workpiece at Gauge Burnishing of its Holes

Papers deal with the application of finite-element method (FEM) when investigating the stress-strain state of the workpiece exposed to the gauge burnishing under the conditions of nonzero friction is considered. The burnishing interference (workpiece deformation degree) is the most important factor influencing the strengthening depth. The mathematical model of the workpiece surface-plastic deformation during burnishing, algorithm and computational results of stresses and deformations are given

Priority oil and gas exploration facilities in the north-east of the Predpatomsky trough

The article discusses the geological structure and prospects of oil and gas potential of the north-eastern part of the Predpatomsky regional trough. The features of the ratio of the structural plans of the upper and lower parts of the geological section due to thrust dislocations are indicated. It is assumed that deep drilling in the area of the Ulugur structure has not reached the target productive horizons in the autochthonous part of the section. Here, after clarifying the scope of seismic work, it is proposed to lay a exploratory well of greater depth. As another priority object for oil and gas, a potential zone of wedging of terrigenous deposits of the Vendian on the southwestern slope of the Suntar uplift is designated. The high prospects of the gas content of the upper part of the section, where gas deposits were established in newly discovered fields, were also noted. The results of direct geochemical testing of the Ulugur and Ergedzheysky license areas are presented, which allow localizing promising zones and areas of the studied territory

Brief communication: Alternation of thaw zones and deep permafrost in the cold climate conditions of the East Siberian Mountains, Suntar-Khayata Range

The Suntar-Khayata Range includes numerous natural phenomena interacting with or depending on permafrost conditions. Here, we examine some patterns of deep permafrost and talik zones on adjacent sites. A 210 m deep borehole in siltstone bedrock was equipped for the temperature monitoring of the topmost 15 m and measurements of a deep permafrost temperature profile in July 2010. The temperature curvature in the upper part has a bend, which is consistent with the upper portion justified by climate warming, and shows a steady-state linear geothermal profile below 85 m depth with a high geothermal heat flux. A shallow borehole situated at the river floodplain was used to investigate the thaw zone's temperature regime. The temperatures down to 6.7 m deep have been monitored at 5 min intervals during heavy rainfall, and the temperature readings have behaved quite peculiarly. The thickness of the seasonal freezing layer reaches 5.7 m; moreover the ground temperature increases to 6 ∘C at 6.7 m depth by groundwater heat transfer. This study provides some new insights into the permafrost condition at one of the coldest places in the Northern Hemisphere.</p

Численное исследование напряженно-деформированного состояния заготовки в контактной задаче поверхностного дорнования отверстий

In recent years, the economic factor has played an increasingly important role in the selection of technologies for manufacturing machine parts with specified values of normalized parameters of geometric accuracy and quality of working surfaces. As applied to surface plastic deformation processes, this is noticeably manifested in the search for effective friction control methods in the “tool – workpiece” pair, which ultimately determines the distribution pattern and the magnitude of stresses and strains in the workpiece and the tool. It is not possible to obtain a rigorous analytical solution to the problem of establishing a connection between surface conditions, friction, and the stress-strain state of the contacted bodies. In this regard, the construction of mathematical models comes to the fore, the solution of which is possible by numerical methods. The paper presents the results of a numerical study (computational experiment) of a finite-element model of workpiece deformation under various conditions of contact interaction and friction by one of the methods of surface plastic deformation – surface mandrel drilling. The friction coefficient has been chosen as the criterion for assessing the conditions of contact interaction and friction. It is shown that a change in the friction coefficient in the process of surface mandrel has no noticeable effect on the formation of a stress field in the deformable workpiece both in the axial, and in the radial and circumferential directions. At the same time, with an increase in the value of the friction coefficient in the “tool – workpiece” pair and with the associated increase in the force of mechanical resistance to deformation of the workpiece, their growth is observed. A computational experiment has confirmed the presence of non-contact deformations of the workpiece and tool during surface mandrel drilling, as well as  as a decrease in the value of residual deformations in the workpiece with a decrease in the coefficient of friction. Balance assessment of contact surface displacements in the workpiece (the inner surface of the hole to be machined) and the tool (mandrel) has shown that the deformations of the tool in the elastic region can lead to a significant decrease in the real tightness of surface mandrel drilling.В последние годы экономический фактор играет все более важную роль при выборе технологий изготовления деталей машин с заданными значениями нормируемых параметров геометрической точности и качества рабочих поверхностей. Применительно к процессам поверхностного пластического деформирования это проявляется в поиске эффективных приемов управления трением в паре «инструмент – заготовка», которое, в конечном итоге, определяет картину распределения и величину напряжений и деформаций в заготовке и инструменте. Получить строгое аналитическое решение задачи по установлению связи между условиями на поверхности, трением и напряженно-деформированным состоянием контактируемых тел не представляется возможным. В этой связи на передний план выходит построение математических моделей, решение которых возможно численными методами. В статье приводятся результаты численного исследования (вычислительного эксперимента) конечно-элементной модели деформирования заготовки в различных условиях контактного взаимодействия и трения одним из методов поверхностного пластического деформирования – поверхностным дорнованием отверстий. Критерием оценки условий контактного взаимодействия и трения выбран коэффициент трения. Показано, что изменение коэффициента трения в процессе поверхностного дорнования не оказывает заметного влияния на формирование поля напряжений в деформируемой заготовке как в осевом, так и в радиальном и окружном направлениях. Вместе с тем при повышении коэффициента трения в паре «инструмент – заготовка» и соответственно силы механического сопротивления деформации заготовки наблюдается их рост. Вычислительным экспериментом подтверждено наличие внеконтактных деформаций заготовки и инструмента при поверхностном дорновании, а также снижение величины остаточных деформаций в заготовке с уменьшением коэффициента трения. Оценка баланса перемещений контактных поверхностей заготовки (внутренняя поверхность обрабатываемого отверстия) и инструмента показала, что деформации инструмента в упругой области могут привести к существенному снижению реального натяга поверхностного дорнования отверстий.

Approaches to the development of online learning In the digital environment of higher education in Yakutia

The authors justified the idea of developing online courses based on the use of Moodle tools, allowing the formation of knowledge in the field of technological and methodological skills and abilities to use educational applications, services, and their application in professional activities in the implementation of online learning in the digital environment of the university.  Assessment of the effectiveness of the online course is confirmed by the solution of professional tasks from the knowledge of the digital educational environment with interdisciplinary content and tasks requiring the use of e-learning tools. Analysis of the results using two-way analysis of variance revealed a significant effect of factors on the effective feature using the F-test. The significance of the study lies in the development of online advanced training courses aimed at improving the technological level of teachers and educators of the Republic of Sakha (Yakutia) in the implementation of the remote format of training using online distance learning tools and technologies.

INCREASE OF STRENGTH OF WELDED JOINTS IN LOW-ALLOY STEELS WITH REGARD TO KINETICS OF SLOWED-DOWN FAILURE

There the influence of kinetics of slowed-down failure on the strength of welded joints in the steels of 14Kh2GMR class has been brought out. The criterion, which incorporates the comprehensive account of manufacturing factors and the use of disinctions of acoutic emission, has been developed. The engineering procedure to estimate the strength of welded joints with regard to the kinetics of slowed-down failure has been offered. The process of erection and repair welding for the welded metalworks operating under the North conditions has been developed. The recommendations for the welding process of metalworks and machines, the Instructions for Repair Welding have been introduced. The introduction efficiency is the rise of strength of welded constructions 1,5 times owing to the developed processAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

The Sundrun population of wild reindeer

The Sundrun wild reindeer (Rangifer tarandus) herd was recognized as a separate population during the 1950s. Since then, the herd has ranged over an area of approximately 180 000 km2 between the Indigirka and Kolyma Rivers in northeastern Yakutia. Population dynamics and movements were investigated between 1987 and 1997. During this period, the population estimates ranged from 25 000 to 45 000 reindeer, the sex ratio averaged 55 bulls:100 cows, and the percentage of calves in the herd ranged between 17% and 25%. The main routes of seasonal migrations, wintering areas, and the location of calving areas are discussed