Северный (Арктический) федеральный университет имени М.В.Ломоносова

When designing, manufacturing and maintaining of woodworks and elements of wooden structures it is necessary to solve the problem of providing the calculation of strength, stiffness and their bearing capacity. This problem becomes particularly relevant while reconstructing and new wooden house building, as the correct choice of connection type influences the technical possibility to use wood in the elements of structures. Such types of special connectors as claw washers, gang nails, dowel connections, etc. are used for these purposes. The existing range of claw washers implies different diameters, thicknesses, and claw configurations depending on the required bearing capacity and cross-sectional dimensions of sawn timber. The accepted physical model of wood is a transtropic body. The forces transmitted in the joints of the elements of wooden structures are perceived by the total contact surface of the mating elements. However, the work of individual teeth of claw washers has been poorly studied: research on influence of geometrical characteristics of the tooth on the bearing capacity of the connector is absent; variation in thickness of the connector is not assessed. A double-sided claw washer of the Bulldog type (prototype) with the diameter of 50 mm was adopted as the object of study. Various schemes of cutting of the claw washer with predetermined dimensions (width and height) of a triangular tooth are considered. The influence of dimensions on the bearing capacity of the thickness of claw washers is estimated within 1–1.5 mm. The main criterion for the selected cutting patterns is the ability to produce the washers by single-impact stamping without additional trimming. Double-sided claw washers of 5 different types with the number of cog-teeth from 8 to 12 items on each side were studied. A differential equation of the 4th order is accepted as a mathematical model of cog-tooth action. The equation describes the behavior of a dowel on an elastic base with a fixed value of bending stiffness EI. The transition to which was carried out from the variable value EI = f(x) by searching for the equivalent width of the cross-section from the bending conditions of the element of the triangular section of a variable directed normal to the frontal surface and a constant directed normal to the lateral surface. For citation: Popov E.V., Ruslanova A.V., Sopilov V.V., Zdralovic N., Mamedov S.M., Labudin B.V. Contact Interaction of a Claw Washer with Wood at Limiting Shear. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 4, pp. 178–189. DOI: 10.37482/0536-1036- 2020-4-178-189
При проектировании, изготовлении и эксплуатации изделий из древесины и элементов деревянных конструкций необходимо решение проблемы обеспечения расчетной прочности, жесткости и их несущей способности, что актуально при реконструкции и в новом деревянном домостроении, так как от правильного выбора вида соединения зависит техническая возможность использования древесины в элементах конструкций. Для этого применяют различные типы специальных соединителей в виде когтевых шайб, кольцевых шпонок, нагельных групп и др. Существующий сортамент когтевых шайб подразумевает различные диаметры, толщины и конфигурацию когтей в зависимости от требуемой несущей способности и размеров сечений пиломатериалов. Принятая модель древесины − транстропное тело. Усилия, передающиеся в соединениях элементов деревянных конструкций, воспринимаются суммарной контактной поверхностью сопряженных элементов. Однако работа отдельных зубьев когтевых шайб изучена недостаточно: отсутствуют исследования влияния геометрических характеристик зуба на несущую способность коннектора, не оценивается изменение толщины соединителя и др. В качестве объекта исследования принят прототип − двухсторонняя когтевая шайба типа «Bulldog» диаметром 50 мм. Рассмотрены различные схемы раскроя шайбы, в которой предопределены размеры (ширина и высота) зуба треугольной формы. Оценивается влияние на несущую способность толщины шайбы (заготовки) в пределах 1,0…1,5 мм. Основным критерием выбранных схем раскроя является возможность изготовления шайб одноударной штамповкой без дополнительной подрезки. Исследовано 5 вариантов двухсторонних когтевых шайб с количеством зубьев 8–12 шт. с каждой стороны. В качестве математической модели работы зуба принято дифференциальное уравнение 4-го порядка, описывающее поведение нагеля на упругом основании с постоянным значением изгибной жесткости EI, переход к которому осуществлялся от переменного значения EI = f(x) путем поиска эквивалентной ширины сечения из условия изгиба элемента треугольного сечения при помощи переменной, направленной нормально к фронтальной поверхности, и постоянной, направленной нормально к боковой поверхности. Для цитирования: Popov E.V., Ruslanova A.V., Sopilov V.V., Zdralovic N., Mamedov S.M., Labudin B.V. Contact Interaction of a Claw Washer with Wood at Limiting Shear // Изв. вузов. Лесн. журн. 2020. № 4. С. 178–189. DOI: 10.37482/0536-1036-2020-4-178-189

The bumblebee fauna of the Southern Taymyr region, northern Siberia, is represented by 10 species, i.e., Bombus consobrinus, B. flavidus, B. lapponicus, B. hypnorum, B. jonellus, B. cingulatus, B. balteatus, B. pyrrhopygus, B. hyperboreus, and B. cryptarum. During the field research for this study, 7 species of bumblebee on the Putorana Plateau (or the Putorana Mountains, on the northwestern edge of the Central Siberian Plateau) and 6 species near Dudinka Town were observed and B. consobrinus was found for the first time on the Putorana Plateau. To date, B. consobrinus was known only in the southern and central parts of the Krasnoyarsk Krai. Regarding the regional fauna, Transpalaearctic and Holarctic species are presented. According to the latitudinal aspect, in this region there are arcto-boreal, arcto-temperate, boreal and temperate species. An analysis of the community was carried out regarding bumblebees that live on the Putorana Plateau. It was found that species of the subgenus Pyrobombus and Alpinobombus, that are typical for the tundra and forest-tundra zones in the Northern Palaearctic, are dominant within the bumblebee community

This article is devoted to a study of the fauna of the long-tongued bees in the north of the Arkhangelsk Region, which is located in the northeast of the European part of Russia, but excludes the Arctic islands. This group includes the bees of the families Megachilidae and Apidae. Forty-four (44) species of bees were found in this region. Most of them (29) are bumblebees (genus Bombus). Fourteen (14) species are megachilid bees (genus Osmia, Coelioxys and Megachile) and one species is Apis mellifera. The largest number of species (39) was recorded in the lower reaches of the Northern Dvina River, due to the long research on this territory. The lowest number of species (16) was recorded in the Mezensky District. In the north of the studied region, the tundra species of B. lapponicus is only presented for the Mezensky District. Many species of bumblebees in the regional fauna belong to the ecological group of the meadow species. These are B. soroeensis, B. ruderarius, B. rupestris and a number of others. They are typical for meadow and ruderal habitats, and are usually not presented in the native taiga habitats. These meadow species are widely represented in the valleys of large rivers, such as the Northern Dvina, the Onega, and the Mezen. Compared to bumblebees, megachilid bees are much rarer in the north of the Arkhangelsk Region. Apis mellifera is presented in the lower reaches of the Northern Dvina River, but here it is rare, compared to the southern part of the Arkhangelsk Region.

Although the Arctic territories have long been considered “the gold standard of purity”, global climate change and environmental pollution are having a significant impact on the state of Arctic ecosystems. In particular, industrial complexes combined with transboundary transport are having a negative impact. The aim of this work is to determine the contribution of atmospheric Pb to the contamination of soils of the Arctic territories using the trajectory statistics method which combines correlation and factor statistical processing approaches while taking the actual lead content in the upper soil horizon into account. In order to assess the transfer of pollutants, an analysis of multiannual air mass tracts and impurity transfer trajectories to certain points was carried out. The objects of study are the soil of the Khorey-Ver settlement, the basin of the Shapkin and Sula rivers, northeastern and southern Svalbard and the islands of the Southern Archipelago of Novaya Zemlya. It was established that the primary contribution to airborne pollution of the Nenets Autonomous District (NAO) during the summer period comes from sources located within a radius of about 400 km. Aerogenic influence of the mainland on the territory of Svalbard is practically absent, with the main atmospheric transport of substances coming from nearby marine areas. The transfer of impurities from the mainland to the Novaya Zemlya District is also insignificant. During the summer months, there is practically no airborne lead contamination of the island territories. Some influences on the territory of Novaya Zemlya and the NEO can be traced to sources on the Kola Peninsula, the coasts of the Barents and Kara seas, as well as long-distance transport from the southern regions. On the territory of the NAO, the number of heavy metal (HM) precipitations increases from west to east, possibly indicating a stronger impact of emissions from the Norilsk industrial hub than from the enterprises of the Kola Peninsula on this territory. In terms of seasonal dynamics, the island points are characterised by an increase in HM fluxes during the winter period; conversely, for the NAO territory, such an increase takes place during the summer. This discrepancy is primarily due to the changing nature of the atmospheric circulation.

Учебное пособие адресовано студентам вузов, обучающимся по педагогическим профилям, но может использоваться для любых направлений подготовки, поскольку включает тексты и упражнения о семье, воспитании, образовании, взаимоотношениях между родителями и детьми, учителями и учениками. Пособие позволяет овладеть навыками англоязычного общенаучного и профессионального общения и может использоваться как для аудиторных, так и самостоятельных занятий.

The training manual "Cultural Space of Europe: Mosaic of Culture & Arctic Dimension" is intended for students, studying the course "Cultural Space of Europe: Arctic Dimension'1 in the programs "Master of European Studies" and "European Research: the Arctic Dimension". This manual presents the author's concept of the tutorial in the interdisciplinary course in the humanities study. The phenomena and processes of the development of the European countries are presented in geocultural and geopolitical aspects.

В статье рассматривается, какое влияние на формирование новых концепций в квантовой механике оказали философские идеи С. Кьеркегора. В «копенгагенской интерпретации» квантовой механики Н. Бор, опираясь на С. Кьеркегора, формулирует принцип дополнительности, также он использует кьеркегоровское понимание субъект-объектного отношения.

The small master thesis is dedicated to the problem of coastal states’ jurisdiction over their marine biological resources, the challenge of ratio between states’ sovereignty and international obligations on conservation management and human rights (collective indigenous peoples’ rights to fishery) and a sustainable use of marine living resources.