Forecast of changes in the beach condition of the Yuzhne city under the influence natural factors

The study of the factors of degradation and the forecast of the state of recreational areas of the coast to prevent their negative changes is relevant. Purpose. Forecast of changes in the condition of the Yuzhne beach, provision of general proposals for its protection from degradation. Methods. Mathematical statistics, linear analysis and mathematical modeling, comparative analysis, cartographic and grapho-analytical studies. Results. The beach of Yuzhne is located on the coast of the Black Sea. Its length is approximately 700 m. The southern direction in the sector 180±22.5⁰ is dangerous for waves. The distance from the beach to the opposite shore (wave acceleration) is 540-610 km. The boundary between the shallow and deep water zones is at a distance of approximately 200 km with a depth of 75 m. With southerly winds, recurring once every 25 years, on the approach to the shallow water zone with a depth of 50-75 m, a developed disturbance with extreme wave parameters is formed, which, transforming in the shallow water zone, significantly affects the coast. A profile of relative dynamic equilibrium with a length of 1,200 m and a depth at this distance of 11.2 m is formed during the calculated disturbance. From the water cut, the boundary between the near-cut and surf zones is located at a distance of 220 m with a depth of 3.6 m. Regardless of the standing water level, the calculated storm destroys the original shore at the extreme parts of the beach. When the sea level is high, the disturbance moves the destroyed material with the beach material into the cut-off zone, while the water cut at the 0.0 m BS mark does not change its planned location. The amount of beach material on the upper part of the coastal slope may decrease significantly. At an average level of the sea, the washing away of destroyed and beach material is accompanied by the advance of the water cut toward the sea for a distance of up to 20 m, but at the same time, a decrease in beach material on the above-water part of the coastal slope is also observed. Conclusion. Without taking special protection measures, the beach of the Yuzhne city will degrade in the future. In areas of the beach, in order to prevent its erosion, it is necessary to erect a retaining wall with a backfilling layer. An option for an active method of protection can be the construction of permeable bunkers on the beach or an intermittent breakwater at a distance from the shore. Such protection will not impede the alongshore transport of sand. Dunes or waves will contribute to the accumulation of sand on the beach. At the same time, after strong storms from the southern direction, with high sea level, episodic additions of sand to the beach are necessar

Solution of the contact problem on indentation of rectangular punch in an elastic roughnesses half-space in the presence of coulomb friction

The numerical solution of the static three-dimensional contact problem of the indentation of a rectangular stamp with a flat base in an elastic rough half-space in the presence of Coulomb friction and previously unknown adhesion and slip zones is obtained. Accounting for surface roughness in this problem is carried out based on the spherical model of microroughnesses by introducing the nonlinear terms describing surface microroughnesses crushing and shearing to the expression of relative displacement of the interacting bodies. The influence of the values of the friction coefficient and the parameters of the microscopic irregularities on the size and shape of the zone of adhesion and the distribution of the tangential contact stresses are analyzed. It is shown that the inclusion of surface microroughness shear forming roughness can lead to a substantial increase in the size of the zone of adhesion

Mesozooplankton Taxonomic Composition of the Canaries Current Ecosystem (Coast of Morocco)

На основе материалов многолетних сборов в пелагиали марокканского побережья экосистемы Канарского течения проведен фаунистический анализ мезозоопланктона (с акцентом на Copepoda): оценен его состав, частота встречаемости отдельных таксонов, а также биотопическая, батиметрическая и зоогеографическая структуры фауны Copepoda. Обнаружены два вида Copepoda, отсутствующие в других фаунистических списках, – южноцентральный Euchaeta paraconcinna Fleminger, 1957 и широкотропический Paracalanus tropicus Andronov, 1977. В фауне Copepoda доминируют океанические широкотропические виды, среди которых поверхностные и интерзональные представлены в равном соотношении. Однако неритические широкотропические виды формируют основу группы константных видов (частота встречаемости более 50 %) и создают фаунистический фон района. Состав групп константных, второстепенных и случайных по частоте встречаемости таксонов достаточно консервативен. Частота встречаемости основных видов веслоногих ракообразных в значительной степени соответствует их встречаемости в прибрежных районах всего Североатлантического субтропического круговоротаOn the basis of the long-term sampling in the pelagic zone of the Moroccan coast of the Canaries Current ecosystem the faunistic analysis of mesozooplankton (with special reference to Copepoda) was carried out. The taxonomic composition, frequency of individual taxa occurrence as well as biotopical, bathymetrical and zoogeographical structures of the Copepoda fauna were assessed. Two Copepoda species absent in the other faunistic lists have been found – south-central Euchaeta paraconcinna and widely-tropical Paracalanus tropicus. Oceanic widely-tropical surface and interzonal species prevailed in the fauna. However, widely-tropical neritic species formed the basis of the constant species group (frequency of occurrence more than 50 %) and created the faunistic background of the area. The composition of the constant, secondary and accidental groups is rather conservative in terms of taxa frequency of occurrence. The occurrence frequency of the main Copepoda species corresponded extensively to their occurrence in the coastal areas of the entire North Atlantic subtropical circulatio

Mesozooplankton Taxonomic Composition of the Canaries Current Ecosystem (Coast of Morocco)

На основе материалов многолетних сборов в пелагиали марокканского побережья экосистемы Канарского течения проведен фаунистический анализ мезозоопланктона (с акцентом на Copepoda): оценен его состав, частота встречаемости отдельных таксонов, а также биотопическая, батиметрическая и зоогеографическая структуры фауны Copepoda. Обнаружены два вида Copepoda, отсутствующие в других фаунистических списках, – южноцентральный Euchaeta paraconcinna Fleminger, 1957 и широкотропический Paracalanus tropicus Andronov, 1977. В фауне Copepoda доминируют океанические широкотропические виды, среди которых поверхностные и интерзональные представлены в равном соотношении. Однако неритические широкотропические виды формируют основу группы константных видов (частота встречаемости более 50 %) и создают фаунистический фон района. Состав групп константных, второстепенных и случайных по частоте встречаемости таксонов достаточно консервативен. Частота встречаемости основных видов веслоногих ракообразных в значительной степени соответствует их встречаемости в прибрежных районах всего Североатлантического субтропического круговоротаOn the basis of the long-term sampling in the pelagic zone of the Moroccan coast of the Canaries Current ecosystem the faunistic analysis of mesozooplankton (with special reference to Copepoda) was carried out. The taxonomic composition, frequency of individual taxa occurrence as well as biotopical, bathymetrical and zoogeographical structures of the Copepoda fauna were assessed. Two Copepoda species absent in the other faunistic lists have been found – south-central Euchaeta paraconcinna and widely-tropical Paracalanus tropicus. Oceanic widely-tropical surface and interzonal species prevailed in the fauna. However, widely-tropical neritic species formed the basis of the constant species group (frequency of occurrence more than 50 %) and created the faunistic background of the area. The composition of the constant, secondary and accidental groups is rather conservative in terms of taxa frequency of occurrence. The occurrence frequency of the main Copepoda species corresponded extensively to their occurrence in the coastal areas of the entire North Atlantic subtropical circulatio