Applied Mechanics and Materials Vol. 186

Abstract: This paper aims at experimental investigation of the active flow control with plasma actuator over an airfoil. The method involved application of single dielectric barrier discharge in order to change the frequency of vortex shedding and the turbulence characteristics from a NACA4412 airfoil. The objective was to reduce control flaps noise in transporting aircraft via an effective body force generated by the actuators. Results indicated that the use of plasma actuator led to a significant decrease in the frequency of vortex shedding around the flap whereas a significant increase in turbulence levels was achieved at a distance away from the actuator.

Abstract: In this paper, Free vibration analysis of a finite length composite shell panel with an embedded piezoelectric sensor, using three-dimensional elasticity solution, is presented. To this end, two different methods are applied to solve the governing equations of the problem. In the first method, the displacement field is derived using trigonometric function expansion in circumferential and longitudinal directions. Using the method of changing variables, the governing partial differential equations are reduced to ordinary differential equations. Then these equations are solved simultaneously with outer and inner boundary conditions to give the natural frequencies and shape modes of the shell panel. In the second method the highly coupled partial differential equations are reduced to ordinary differential equations by means of trigonometric function expansion in circumferential and axial directions and then the finite difference method is applied to evaluate the obtained differential equations in radial direction. Then, the natural frequencies of the multi-layered panel are calculated using the obtained ordinary differential equations. At last, some numerical examples are presented to compare the results obtained by these two different methods. Three layered laminated shell panel is assumed to be [0/90/P].

Abstract: Abstract. The paper presents a strategy for the dynamic hybrid force-position control of the walking robot motion on slope using the ZMP method for dynamic control and a stable and robust method. Through dynamic and kinematic modeling of the walking robots motion an open architecture system was developed which contains five control interfaces. The stability problem of quadruped walking robots, through extendible segments which are designed to reduce the difficulty of walking on slope, and also by using them to avoid obstacles that may occur during a stepping cycle are presented. The results obtained have led to an improvement in the response time to disturbances, to tracking the motion trajectory with higher precision in conditions of high stability and to development of new technological capabilities, adapting the robot walking to movement over sloped terrain, with obstacles and bumps.

Abstract: In this study the tangential contact stiffness between two elastic bodies having nominally flat surfaces with different material combinations is investigated. The tangential contact stiffness between these two elastic bodies is first calculated based on the Greenwood-Williamson-McCool contact theory. Then, the tangential contact stiffness is determined by experimental investigation on a tribometer under the effect of different values of normal load and tangential displacement amplitude. The tangential contact stiffnesses obtained from the experimental data show a good agreement with the theoretical results, where the trends are similar and they are in the same order of magnitude.

Abstract: Increasing the conversion efficiency of the solar energy into electricity is one of the most addressed topics in the field of renewable energy systems. In this paper, the pseudo-azimuthal tracking mechanism for a PV platform it was selected for presentation. The study is focused on the optimization of the mechanical device model of the tracking mechanism (developed with the MBS software environment ADAMS of MSC). The optimization is based on the parametrization of the model by using the design points that define the locations of the geometric constraints (i.e. the joints). The objective of the optimization is to minimize the motor force developed by the driving source, which is a linear actuator. In addition, a design constraint is used to limit (restrict) the value of the pressure angle. The optimization study leads to the minimization of the energetic consumption during tracking, with positive effect on the energy balance of the photovoltaic system with sun tracker.

Abstract: This paper presents an algorithm and implementation of remote control testing products over web interface. The testing device is programmed to work in a both automatic and manual mode. Automatic mode testing sequences are programmed by the user from a browser by entering time of the test, several variables (angle, focus, etc.) and the system repeats the process for programmed time. Manual mode offers user testing procedure at a desired time and steps. Our approach combines efficient common user interface with an algorithm to realize programmed tests.

Abstract: The flammability characteristics and synergistic effect of zinc borate with antimony trioxide in araldite resin composite have been studied by thermal erosion test . Zinc borate was added first to araldite resin reinforced by hybrid carbon-Kevlar fibers as a surface layer(5mm) thickness .Then, the result composite material was exposed to a direct flame generated from Oxyacetylene torch (3000°C) with different flame exposure intervals (10,20mm), and study the range of resistance of retardant material layer to the flames and protected the substrate .After that , antimony trioxide was added to zinc borate with various amount(10%,20%,30%) to forming a hybrid flame retardant for enhance the action of this material to react flame . Hybrid retardant exposure to same flame temperature and exposure distances. Method of measuring the surface temperature opposite to the flame was used to determined the heat transferred to composite material . the best results was obtained with large exposed distance and large percentage from protective layer which is zinc borate with (30%) antimony trioxide .

Abstract: The paper deals with a surveillance system dedicated to close spaces which could be used in several situations: museums, banks, public institutions, airports. The authors continued a previous research [1] with applications in robotics. We developed a system based on detection with eight IR sensors and tracking with a video camera. This system has very good performances and a low price.

Abstract: The paper presents the hardware structure of an original hydraulic positioning system based on a mechatronic approach. Dedicated control algorithms are also presented.

Abstract: In this paper, the mechanical properties of extended drug release systems were studied. A binder is a material that is added to a formulation in order to improve the mechanical strength of a drug release system. The drug release systems investigated were cylindrical tablets containing mixtures of various ketoprofen types and binders. Among the binders used were a series of different molecular weights of kollidon va 64, carbopol 971 pnf, hydroxypropyl methyl cellulose and sodium carboxyl methyl cellulose. The samples were made in the form of cylindrical tablet of about 9 mm in diameter and containing different mixtures of drug substances and excipients in three formulations. Mechanical parameters such as hardness, tensile stress and friability were studied in order to determine how they are influenced by binder and how it influences wetting and disintegration of tables.