25 research outputs found
Axially symmetric gravitational fields. IV. Static solutions of the Einstein-Maxwell equations
Summary: "This review article is an attempt at the systematization of known particular solutions of static axially symmetric Einstein-Maxwell equations. The order of presentation is based on considering different methods of solving the static Einstein-Maxwell equations." par {For Part III see [Ts. I. Gutsunaev and A. A. Shaideman, Gravit. Cosmol. {bf 9} (2003), no.~4, 229--234; [msn] MR2061354 (2005b:83027) [/msn]].
Stationary euclidon in the gravitational field
In the paper the authors first introduce a euclidon solution of the Einstein equations. This is a solution to the Einstein vacuum equations which is axially symmetric and stationary and flat. Physically, a solution of this kind characterizes some relativistic noninertial frame of reference in flat space-time. Then the authors use this euclidon solution to generate new axially symmetric and stationary solutions to the vacuum Einstein equations. par The method of generating these new solutions is based on a nonlinear composition of an arbitrary axially symmetric and stationary solution to the vacuum Einstein equations called the seed solution with the euclidon solution. par Finally, the authors show that the method reduces to integrating a set of first-order linear differential equations. Any set of equations of this kind can be solved in general because methods of treating a set of first-order linear differential equations are very well known. par The paper is interesting and important for the problem of obtaining new exact solutions to the Einstein equations
945 RETROPERITONEAL LYMPH NODE DISSECTION AFTER INDUCTION CHEMOTHERAPY IN METASTATIC TESTICULAR NON-SEMINOMA
THEORETICAL SUBSTANTIATION OF THREE-BLADE ROTARY FEEDER
The analysis of resource-saving technologies of cultivation and refinement of agricultural crops confirmed that the use of PSS pneumatic sorting tables allows to somewhat reduce the costs of cleaning and sorting. However, the imperfection of their designs and uneven grain supply reduces the effectiveness of their use. Therefore, the purpose of the research was to improve the quality of post-harvest processing of grain crops, the development of a rotary feeder. To achieve this goal, research methods and techniques have been developed. A pneumatic sorting table equipped with a three-blade rotary feeder with an outer diameter of 80 mm with straight blades located at an angle of 120 degrees has been developed. The process of grain flow motion in the hopper was studied and dependencies were established to determine grain motion in the hopper, the time of grain motion in the area under consideration and the speed of grain motion at the exit from the hopper, which was 1.167 m/s. The equations of motion of the blades for the outer and inner diameter of the rotary feeder are established, according to which the actual coordinates of their motion and displacement of the shaft axis of the rotary feeder from its original position are calculated. Calculations have determined that with an outer diameter of 0.08 m of the rotary feeder, grain velocity of 1.02 m/s, an angular velocity of 2.9 s-1, the displacement of the shaft axis of the rotary feeder from its original position at a 360 degree rotation angle will be 160 mm. This will reduce the unevenness of grain supply, and grain shattering, increase laboratory and field germination, improve the content of the output groups of full-fledged grain and, consequently, improve the quality of post-harvest processing of grain crops by a developed pneumatic sorting table equipped with a three-blade rotary feeder