Investigation of the Earth Ionosphere using the Radio Emission of Pulsars

The investigation of the Earth ionosphere both in a quiet and a disturbed states is still desirable. Despite recent progress in its modeling and in estimating the electron concentration along the line of sight by GPS signals, the impact of the disturbed ionosphere and magnetic field on the wave propagation still remains not sufficiently understood. This is due to lack of information on the polarization of GPS signals, and due to poorly conditioned models of the ionosphere at high altitudes and strong perturbations. In this article we consider a possibility of using the data of pulsar radio emission, along with the traditional GPS system data, for the vertical and oblique sounding of the ionosphere. This approach also allows to monitor parameters of the propagation medium, such as the dispersion measure and the rotation measure using changes of the polarization between pulses. By using a selected pulsar constellation it is possible to increase the number of directions in which parameters of the ionosphere and the magnetic field can be estimated.Comment: 13 pages, 4 figures, Baltic Astronomy, vol.22, 53-65, 201

Fabrication of the Ni[3]Al-based alloy formed by spark plasma sintering of VKNA powders

The material based on Ni[3]Al intermetallic has been obtained from the industrial powder of a VKNA type by the method of spark plasma sintering. Materials sintering was conducted at the temperature of 1100 °С, compacting pressure of 20 MPa, and during soaking time equal to 5 minutes. The heating rate of samples amounted to 50 and 200 °С/min. It has been established that the material obtained by sintering at the rate of 50 °С/min possesses a maximum value of density (5.93 g/cm{3}) and a maximum level of bending strength (~ 400 MPa)

Flow of forces and couples to the cylindrical solids through system asymmetry thin-walled elements of varying stiffness

Задача про передачу силового і моментного навантаження до криволінійного отвору нескінченної ізотропної пластинки через систему несиметричних відносно серединної площини тонкостінних елементів змінної жорсткості зведена до системи чотирьох сингулярних інтегрально– диференціальних рівнянь з ядрами Гільберта. Методом колокації досліджується вплив на напружений стан пластинки несиметричності підсилень, способу їх розміщення на контурі отвору.The problem of flow of forces and couples to the curvilinear hole in a infinite isotropic plate through system of asymmetrical by a middle plane the thin-walled elements of varying stiffness reduce to the system of four singular integral-differential equations with cores of Hilbert. The effect of asymmetry strengthens and location mode by method of collocation does investigate

The elastic equilibrium plate with curvilinear contour the partial strengthened by the system of the three asymmetrical ribs

Досліджується напружено-деформований стан на контурі криволінійного отвору, частково підсиленого системою трьох несиметричних ребер змінної жорсткості, в нескінченній пластинці, яка перебуває в умовах узагальненого плоского напруженого стану і циліндричного згину. Побудовано систему восьми сингулярних інтегрально-диференціальних рівнянь з ядрами Гільберта для визначення контактних напружень в зоні підсилення. Встановлено структуру її наближеного розв’язку. Для трикутного отвору розглянуто числовий приклад.The mode of deformation contour the curvilinear hole the partial strengthened of the three asymmetrical ribs of varying stiffness in a infinite plate is analyze. The plate to be of generalized plane stress state and cylindrical bend. The system of eight singular integral-differential equations with cores of Hilbert for definition contact tensions in the area of strengthened is constructed. The structure of approximate solution of this system is explored. For the triangular hole numerical illustration is considered

Force method application for static calculation of closed curved bar

Розглянуто задачу розрахунку напружено-деформованого стану замкненого криволінійного пружного стрижня, який перебуває в умовах симетричного відносно осі бічного розподіленого навантаження. З використанням методу сил побудовано уточнений варіант повної системи рівнянь одновимірної теорії таких стрижнів. Розв’язок задачі реалізовано методом скінченних тригонометричних рядів.Within geometrical linear theory of deformations using of the hypotheses of normal plane section refined version of the complete system of equations of one-dimensional theory of closed thin elastic bars of rectangular cross section is constructed. They are modeled by the locked curved rods. The bars are in a plane stress created by external force applied to lateral surfaces of the bar. Considering that the main axis of the cross section coincide with the direction of axes of natural trihedron of a fixed fiber of a bar and neglecting the deplanation of cross sections the formula to determine the internal longitudinal and lateral forces and bending moments, referred to the axis of the bar, are deduced. These formulas are equivalent to the differential equilibrium conditions of an element of bar. To determine the reactions of redundant constraint of static uncertainty closed bar in the conditions of a symmetric stress the force method is used. Physical relations between the longitudinal forces and bending moments and certain deformations of fixed fiber of a bar are built on the basis of consideration of deformation of its infinitesimal areas. Neglecting the influence of cross-axis forces and deformation of the cross section of the bar the conditions of compatibility between displacement points of random fiber and its deformation are recorded. These conditions allowed to express components of the displacement vector of the point of the bar through two one-valued functions, which depend on the external load. The special cases of problems for the bar, modeled by elastic line with tension (compressive) and bending stiffness or flexible elastic line are examined. Expressing symmetrical external load by finite trigonometric sums the method of calculation of mode of deformation of the bar with smooth contour without angular points is developed