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The slope stability analysis and support structure design of temporary roads are particularly important for the normal traffic of roads and the safe construction of underground structures. In this paper, FLAC3D software is used to study the numerical simulation of steel pipe piles support structure of the slope of temporary road by using the equivalent stiffness method. It is shown that under the action of road load, the normal stress of steel pipe pile has a peak value at 1.0m above the bottom of foundation pit, and the shear stress has two peaks at 1.0m above the bottom of foundation pit and 0.5m above the pile tip, which decrease at the pile tip. The horizontal displacement of the pile occurs at different depth, the displacement of the pile top is the largest, and the displacement from the pile top to the bottom of foundation pit decreases nonlinearly, and the horizontal displacement of the pile below the bottom of foundation pit is very small and remains unchanged. The vertical displacement of the pile increases gradually from the pile top to the pile tip, which results in tensile deformation of the pile. Stress concentration occurs at the temporary road position in the slope, and obvious horizontal displacement and vertical displacement which have obvious differences in different positions appear in the slope. The arrangement of piles can ensure the stability of the slope and there will be no overall shear failure surface. [ABSTRACT FROM AUTHOR]

In this paper the continuous bending under tension (CBT) test is analyzed by numerical simulation. In CBT test, the material is deformed to high level of strain that is beyond the achieved strain by the standard tensile test. The main stability criterion describes the importance of compressive stress produced by bending in stabilizing the deformation. At the symmetry line of the strip, the material can be assumed simply to deform by bending and stretching in plane strain condition. The focus of this paper is to study the deformation modes through thickness at the symmetry line. It is found that the material experiences three deformations modes. The cyclic parts through thickness experiences two deformation modes: the first is limited between uniaxial tension and plane strain and the second deformation mode is limited between pure shear and uniaxial compression. The third deformation mode is observed at the middle part through thickness and it is based on tension and the contribution of through thickness stress. [ABSTRACT FROM AUTHOR]

This paper describes a number of computer aided design (CAD) tools that are used in the development of surface micromachined mechanisms. It investigates the application of parametric or constraint-based CAD in the design of these mechanisms. Parametric CAD facilities are compared with conventional CAD facilities in this paper. The advantages and limitations of conventional and parametric CAD are illustrated by describing their application in designing an electrostatically actuated crescent pump mechanism, which was fabricated in five levels of silicon using Sandia.s Ultraplanar Multilevel Micromachining Technology (SUMMiT-V). The paper also describes the application of visualization and motion simulation tools in designing surface micromachined mechanisms. [ABSTRACT FROM AUTHOR]

For the main purpose of studying the tooth surface equation and undercutting conditions of the cylindrical gears with curvilinear shaped teeth processed by parallel translating mechanism, the tooth surface equation and meshing condition of the cylindrical gears with curvilinear shaped teeth processed by parallel translating mechanism were deduced by the method of differential geometry and coordinate transformation, based on considering cutting tool shape and installation position error. The undercutting line of the cylindrical gears with curvilinear shaped teeth processed by parallel translating mechanism was also calculated. The manufacturing process of the parallel translating mechanism was simulated in threedimensional software and then the three dimensional solid model of cylindrical gears with curvilinear shaped teeth was obtained. The studies referred to in the present paper have a certain reference value for research, development and design of the cylindrical gears with curvilinear shaped teeth processed by parallel translating mechanism. [ABSTRACT FROM AUTHOR]

Hydraulic and electromagnetic forces are main causes of vibrations in a hydraulic generating set. The Unbalanced Magnetic Pull (UMP) and nonlinear sealing force can produce large oscillations which will be dangerous to the shaft system. In the present paper, the kinetic model of a simplified unit shaft system, which mainly considers 6 degrees of freedom of rotor and turbine, under UMP, and Muszynska nonlinear sealing force is established. On this basis, the nonlinear stability of Francis turbine-seal system is emphasized, and the effect of the seal parameters on system stability is also discussed, according to the Lyapunov first approximation theory. The results show that there is very little likelihood of rub-impact phenomenon occurrence between the turbine and seal structure with nonlinear sealing force, if no other external interferences are taken into account. In addition, some suggestions about reducing self-excited vibration by parameters sensitivity analysis are given, which can be beneficial to the safety operation and vibration fault diagnosis for the units. [ABSTRACT FROM AUTHOR]

Exergy analysis identifies potential factors responsible for thermodynamic losses and leads to efficiency improvements. In the present paper, exergy efficiency is expressed as a function of dimensionless mass flow rate and outlet fluid temperature. A computer program was developed for determining the optimal performance parameters for maximum exergy efficiency in a flat plate collector. The study was conducted for six collectors of different areas, having a different overall loss coefficient and a heat removal factor. It is observed that for given values of incident solar radiation, inlet fluid temperature and ambient temperature, the optimal mass flow rate varied from 0.0019 -0.0022 kg/s and exergy efficiency varied from 5.2- 8.2% for the collectors depending on its gross area, overall heat loss coefficient and heat removal factor. [ABSTRACT FROM AUTHOR]

Determining the optimum tilt angle for PV system based power plants is crucial to be considered when fixing the PV systems. Although the optimum tilt angle is normally close to the latitude value of the location, lots of other factors affect this. So when designing a power plant, it is necessary to take these factors into consideration to maximize the output of those plants. The present paper reviews the main scientific concepts related to solar radiation, the models used to describe the solar radiation properties, and the methods of calculating the optimum tilt angle. The optimum tilt angle for northern Jordan and, as a case study, Jordan University of Science and Technology (JUST) Campus is then calculated by applying the appropriate methods and models. In addition to that, simulation software is used to calculate the optimum tilt angle and the yield of the power station. Other factors affecting the tilt angle of a PV array are reported and relevant recommendations are given. [ABSTRACT FROM AUTHOR]

A series of experiments of a pick cutting coal seam in different forms were conducted on a cutting testbed of coal and rock. Rotational speeds of the pick and initial velocities of the coal seam in the experiments are uniformly set to be 60 r/min and 0.6 m/min, respectively. Based on the amplitude domain analysis of the cutting force-time signals of the pick cutting rock with different Compressive Strength (CS), it is found that force increment between the pick cutting rock and uniform coal seam linearly increases with the increase of CS difference between fault and coal, and the larger the CS is, the larger the load fluctuation is. Amplitude domain analysis of the signals of the pick cutting coal seam with coal and rock interface at different locations shows that the force increment of the pick cutting the coal seam with coal-rock interface at the center of the coal seam is the largest, compared with those of the pick cutting the coal seam with coal-rock interface at the top and at the bottom, but smaller than the sum of them. [ABSTRACT FROM AUTHOR]

A thermodynamic based model was developed. The influences of thermo-physical parameters on the Stirling engine performance were investigated. The analysis is mainly performed inside the compression and expansion cylinders. The instantaneous temperatures of the working fluid inside the engine cylinders, and the interconnected heat exchangers were investigated. The system of governing equations (mass and energy) was developed and employed to investigate the variations of all the process parameters. The step-by-step crank angle intervals were applied to investigate the pressure, temperature, volume, mass flow, and convective heat transfer during the compression and expansion processes. Losses of mass due to the leakage, and energy losses were investigated under the adopted working conditions and phase difference. Variation of work generation due to the leakage of gas through the clearance between the piston and cylinder was evaluated. The numerical solution was adequately performed with a large number of iterations and for each angular interval. A noticeable stable evolutional behavior of the simulated parameters was observed. The stable evolutional behavior of the simulated parameters confirms the model suitability, the capability of pointing out the engine performance, and the capability of converting the thermal energy into useful mechanical work. Additionally, the use of other related correlations ensures the model accuracy, while the resulted small differences are within the expected ranges. In comparison with similar studies, the calculation procedure can be used to investigate the engine performance under different operating conditions. [ABSTRACT FROM AUTHOR]