Applied Mechanics and Materials Vol. 763

Abstract: Various bio-related processes are driven by electron transfer reactions. Therefore the electronic structures of bio-molecules in their living environment are keys of their functionalities. One significant example photosynthesis which has attracted much attention due to urgent necessity of clean energy source. In this study, we carried out photoelectron yield spectroscopy (PYS) measurements to demonstrate the electronic structures of oligomerizedChl-a molecules, which is known as an essential reaction center of the photosystem in general green plants, under the atmospheric environment. The ionization energies of the Chl-a aggregates are successfully derived.

Abstract: This paper presents a design and implementation of Brushless DC (BLDC) motor speed control based on the TMS320F28335 DSP board interfacing to MATLAB/SIMULINK. To obtain the optimal tracking and regulating responses, the PI controller is conducted and designed by pole placement technique. With Back EMF detection, the proposed system is considered as a class of sensorless control. This scheme leads to the speed adjustment of the BLDC motor by PWM. This experiment aims to examine the effectiveness of BLDC motor by testing the BLDC motor of 100 watt. It was found that the speed response of BLDC motor can be regulated at the operating speed of 700 rpm and 1400 rpm at no load and full load conditions.

Abstract: The paper presents theoretical dependences to calculate the main parameters of the pneumatic actuator of the multi-stage manually synchronized transmission depending on the parameters of the engine, the transmission and conditions of running resistance during the synchronization process at alternating pressure with different types of the air discharge into the pneumatic cylinder: critical, subcritical and at constant pressure. Comparison of results theoretical and experimental studies on the test stand shows that the calculated values of synchronization time on certain stages and throughout the cycles of the transmission shifting differ from the experimental data by 10-25% maximum.

Abstract: We investigated the modes of operation of the drive and loading electromechanical systems of the test loading stand, which provides necessary motion trajectories and changes loads of steps in transmission with command and automatic control. We revealed the factors that determine accuracy and dynamic properties of the controlled dynamical system with elastic mechanical constraints. We proposed system structures of energy-saving power consumption in the node connecting the stand to the electrical network.

Abstract: In this study, reduction of cogging torque and torque ripple for an exterior rotor type brushless dc (BLDC) motor for an automotive cooling device were proposed and a design concept for a fan motor for use in a battery pack mounted in an electric vehicle/hybrid electric vehicle (EV/HEV) was presented. Various pole/slot combinations and permanent magnet (PM) pole arc ratios were compared using finite element analysis (FEA), and the PM overhang ratio necessary to sufficiently increase the magnetic flux that enabled coil linkage was determined through 3D FEA. Based on the analysis results, an actual model was produced, experimentally verified, and used to validate the proposed design model.

Abstract: There was performed the analysis of a set of methodical solutions for determining of current and limit plasticity of welded joint zones at large diameter pipes. To determine the current plastic deformation of zones of pipes' welded joints it is offered to test the natural ring of a height of 80 mm, of a pipe with size 530x7,5 mm made of steel 17GS, welded by arc welding using a welding wire SV-08HM under a layer of flux AN-60. The ring samples are tested in the cone, the constructive dimensions of which match the cone used on the expander by the definite value of broadening on the hydraulic press with the force not less than 500 tons. The results of tests of ring samples of welded pipe with size 530х7,5 mm while their broadening by the cone. To determine the limit of plastic deformation of zones of a welded joint of large diameter pipes a method for testing a flat sample is proposed. The construction of the sample and the scheme of loading to determine the limit plasticity of welded pipe joints are proposed.

Abstract: Two main factors for design of railway vehicles are stability and curving performance. Running performances, result from stiffness design of a primary suspension, between stability and curving are contrary to each other. The more longitudinal stiffness of a primary suspension stiff, the better straight performance is outstanding, however, curving performance is degenerated. Also, if the less longitudinal stiffness stiff, running performance has opposite characteristics. Curving performance of railway vehicles should be outstanding on small curved track which is in cities. If curving performance is improved, lateral contact force (i.e. flange contact force) of wheel and rail is decreased by improved spring so, wear and noise of wheels are decreased. Derailment risk from wheel and rail contact, of course, is decreased. Thus, it's important to design an axle spring of a primary suspension. The design of ensuring stability performance, of course, should be precede. An axle spring is designed using FEM tool which is ABAQUS also, rubber like material is modeled by Mooney-Rivlin model. Developed FE-axle spring model is analyzed and is produced also, this model is validated by test results of a load tester.

Abstract: Luneburg lens is a gradient index lens that focuses the incoming wave to the opposite side of the lens without aberration. We developed a two-dimensional acoustic Luneburg lens by variable density method of space inside the lens. The lens is composed of hundreds of aluminum columns with various radii of less than 1cm. We tested the ability as sonar in the air. It focuses the incoming acoustic wave on the edge of the opposite side of the lens as well in the frequency range of 1,000Hz ~ 3,000Hz. It showed a dynamic response depending on the motion of the acoustic source. It could be a strong candidate of a next generation of sonar.

Abstract: In recent years, the issues of indoor air quality and thermal comfort in underground garages have attained considerable importance. The purpose of this study is to present a green natural ventilation system with a ventilation shaft connected to the outdoors through a horizontal branch pipe. The system combines with a diaphragm wall and steel cage frame for an underground garage or similar underground enclosed spaces. The design system reduces use of tradition fans and motors used in mechanical ventilation. It improves exhaust from indoor spaces and reduces energy consumption. The green design of the ventilation system in this study is cost effective, saves energy and improves the air quality in an underground garage.

Abstract: Problem of a mobile object positioning in the presence of determinate disturbances is considered in this paper. A mobile object is described by kinematics and dynamics equations of a solid body in three dimensional space. The control inputs of the mobile object are forces and torques. Design of adaptive control is based on position-path control method for mobile objects. In this article two algorithms of the adaptive position-path control are developed. The first algorithm is adaptive position-path control with integration component and a reference model. The second algorithm is adaptive position-path control with a reference model and an extended mobile robot model. Block diagram of the direct adaptive position-path control system with a reference model is suggested. Design procedures of the adaptive position-path control systems and stability analysis of the closed-loop systems are presented. Computer simulation results of the designed adaptive closed-loop systems with both constant and variable disturbances are presented. On base of the analysis and modeling results conclusions are provided.