Optimizing Effect of Wavy Leading Edge (WLE) in Rectangular Wing and Taper Wing

Experimental and numerical research have been performed to investigate the Wavy Leading Edge (WLE) effect on the rectangular wing. The WLE is inspired by humpback whale flipper morphology which is blunt and rounded in certain form pattern. This flipper shape plays an important role for its behaviour specially capturing their prey. This advantage could be applied to other systems such as fin stabilizers or wind turbines. Steady cases in various aspect ratios were conducted to find out the optimum effect of WLE with baseline NACA 0018 profile at Reynolds number 1.4 x 105. The chord length of the wing (c) was 125 mm. The WLE shape defined as wavelength (W) 8% of c and amplitude (d) is 5% of c. The aspect ratio (AR) variations were 1.6; 3.9; 5.1; 7.9 and 9.6. A simple rectangular form of the wing was selected to analysis the WLE effect on the various ARs. The taper wing shape is applied to find out the WLE effect at the AR 7.9. three types of taper ratio (TR) are 0.1; 0.3 and 0.5. The results show that the WLE on the taper wing has better advantage to control the stall in steady case. Another impressive result was the WLE wing with AR 7.9 and TR 0.3 has the best lift coefficient and pressure distribution.Keywords: stall, wavy leading edge, steady case, rectangle wing, taper wing, aspect ratio.

Angels as the Shape of Energy: How the Threshold Narratives Shaped the Meaning Construction of ‘Angel’ and ‘Energy’ in a Central and Eastern European New Religious Group

The status-dependent access to information results in multilevel meaning construction in a charismatic Christian group. The notion of ‘angel’ is discursively transforming (during evangelization rituals, healing, angel visions, etc.). To acquire language skills, one may encounter and accept threshold narratives. After the notion of energy was introduced into the group (2012), former ideas (‘rectangular form’ and ‘shape-changing kind’ of angels) were intermixed with it. Energy became a general, fundamental principle, but it was not obvious how they could manage its dual kind: ‘positive energy’ and the evil counterpart (‘spiritual/negative energy’). My argumentation is based on discourse analysis and cognitive semantics.

LAMİNASYON TEKNİĞİ İLE ÜRETİLEN FİLMLERE UYGULANAN TEKRARLI YIKAMALARIN, PARLAKLIK, LAMİNASYON KUVVETİ VE OPTİK DANSİTE ÖZELLİKLERİ AÇISINDAN ETKİLERİNİN İNCELENMESİ

Metalized yarns are produced by cutting the films in different thicknesses, metalized with aluminum on one or both sides, in a rectangular form in the desired dimensions and wrapping them on bobbins under a certain tension. Textile products made of these yarns are exposed to repetitive washings like most textile products; metal surfaces of metalized yarns are abraded over time, their bright appearance decreases or disappears. It is undesirable because it affects the lifetime of the final product. In the study, laminated films were produced by the lamination technique using different raw materials to produce metalized yarns with the improved fastness and mechanical properties. Laminated films were subjected to repetitive washings at different temperatures, and the effects of washings on the surface appearance of the films, lamination strength, and optical density properties were examined. As a result of the study, it was determined that repetitive washings reduce the lamination strength, the gloss property is affected by raw material type, the sample type, washing temperature, and the number of washing cycles affect the optical density.

Studying Settlement Gorodishche 1 in the Zonalnyi District

The article is devoted to the publication of obtained materials from a site in the Itkul archaeological district that includes a settlement called Gorodishche 1. The site is located on the southern shore of Lake Bol'shoi Itkul, on the border of the Zonalnyi and Troitskii districts. The land plot of the settlement has a complex layout and is limited by a moat. At the site, an area of 64 square metres was excavated, as a result, a dwelling pit and a small part of the moat were investigated. The dwelling was a semi-hut of a semi-rectangular form with an open hearth. The area of the dwelling was about 28 square metres. The location of the materials in the dwelling pit shows the special features of the layout. The place of entrance was identified. The economic zone was distinguished by the location of the hearth and the accumulation of ceramics around it; it was located at the farthest wall from the entrance. There were not many finds in the cultural layer. The finds were represented by clusters of ceramics. The vessels were round-bottomed, of lowered proportions, decorated with ornament in the upper part. The most common elements of the ornament were pits. There was also a comb duck ornament. Just one element was used in the ornamental composition. The features of the ceramic complex allowed the authors to refer the studied site to the Fominskaya stage of the Kulaiskaya culture and date it within the 2nd-4th centuries. The material is published for the first time.

Bivariate Interpolation in Rectangular Form

The purpose of this paper is to derive lagrange interpolation formula for a single variable and two independent variables. Firstly, single variable interpolation is derived and then two independent variable interpolation derived. Some practical problems are computed by virtue of these interpolation formula.

SYSTEM DEVELOPMENT FOR DEFINITION OF CONTACT INTERACTION MODE IN LINK OF SLIDING ROBOT WITH OBSTACLE

The paper is dedicated to the problems of a link motion in a sliding robot on a horizontal surface with obstacles. The motion of a robot link is under consideration in case when one of its bearings located in utmost points is fixed on the surface and the second slips, that is, a link moves on an arc of a circle, at that a robot itself changes its configuration. A distinguishing peculiarity and advantage of this work is that in it there is no consideration of a specific design circuit of a sliding robot with the definite link number and type of swing joints between them, but a link turn on the plane under condition of the presence of mobility rotating degree in a hinge connecting links and friction control in bearings is only considered. In the work there is offered a four-level system for motion control of a robot link on a surface with obstacles where each of them is modeled in a rectangular form. A system for the mode definition of a link contact with an obstacle is considered thoroughly, the following possible modes are emphasized: the interaction of utmost points of a link and an obstacle, the utmost point of the link with the point on an obstacle side, a certain point of a link with the utmost point of the obstacle, a link with the obstacle side and the absence of the contact of a link and an obstacle. For each of the modes mentioned there are written conditions for its occurrence and also a necessity of link motion updating in order to surmount obstacles (a set of regulations for a system operation) is defined. The information on updating necessity comes to a corresponding level of the control system and then to the system of robot driving gear control that allows realizing such a link motion which ensures overcoming obstacles. Key words: sliding robot, robot link, friction control, obstacle, mode of contact ineraction.

Design and Development of a Compact Rat-Race Coupler

In this paper, design and development of compact Rat- Race coupler is presented. The device is designed with commercially available semi rigid coaxial cable. The semi rigid coaxial is modified for desired impedance to suit the requirement of Rat- race hybrid coupler. The physical structure of the coupler is in rectangular form instead of the conventional ring form. With this structure, all the ports are available in line on the same side. This eases the integration of the device with other modules or devices in the system. The total area occupied the coupler is reduced drastically by meandering the transmission line. The shielded transmission line provides better port isolation and less radiation loss. Design, implementation and measured results are presented.

Unsteady RANS Simulation of Air Distribution in a Ventilated Classroom with Numerous Jets

The study is devoted to the Unsteady Reynolds-Averaged Navies-Stokes (URANS) simulation of ventilation in an isothermal room with numerous jets supplied from ceiling diffusers. The computations of the airflow under the test conditions considered were carried out in the classroom of the Technical University of Sofia with no occupants. The room floor has a simple rectangular form, but several columns, beams, window sills, and four radiators are located inside the room that makes the geometry more complex. Air is supplied to the room through four ceiling fan coils, the Reynolds number is 2×104. Calculations were carried out using the ANSYS Fluent 18.2 software with the standard k-ε turbulence model chosen. Computational meshes of up to 33 million hexahedral cells clustered to the inlet and outlet sections were used. The main aim of the study presented is to analyze and discuss the complicated 3D flow structure in the room and to give foundation for future measurements of air velocity field in the room.