Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 7 Articles
This research aims to improve the plant layout of manufacturing industry to make optimum space utilization, eliminate obstructions in material flow and thus obtain maximum productivity. Various optimization approaches for small problems and heuristic approaches for the larger problems have been proposed to elucidate the problem. The and operation process of each section (i.e. Material storage, Cutting, Welding, Grinding , Drilling, Machining shop I,II,III , CNC shop and inspection section and finish product storage) have been investigated. The problem in the space utilization and material flow pattern was identified. Various techniques were applied after finding the solution through traditional methods to get much improved optimum solutions..The suitable of new plant layout can decrease the distance of material flow, which rise production...
Laser tracking system (LTS) has been widely used in energy industries to meet increasingly high accuracy requirements. However,\r\nits measuring accuracy is highly affected by the dynamic uncertainty errors of LTS, and also the current range and angle\r\nmeasurements of LTS are mainly weighted statically, obtaining the dynamic weighting model which is essential for LTS to improve\r\nthe measuring accuracy. In this paper, a dynamic weighting model that describes not only the dynamic uncertainty but also the\r\ngeometric variations of LTS is developed, which can be adjusted to the weighting factors of dynamic parameters according to\r\nthe range observations relative to the angle observations. Intensive experimental studies are conducted to check validity of the\r\ntheoretical results. The results show that the measuring accuracy of LTS has been increased 2 times after using this technique for\r\ncorrection....
The shaft tubular turbine is a form of tidal power station which can provide bidirectional power. Efficiency is an important turbine\r\nperformance indicator. To study the influence of runner design parameters on efficiency, a complete 3D flow-channel model of a\r\nshaft tubular turbine was developed, which contains the turbine runner, guide vanes, and flow passage and was integrated with\r\nhybrid grids calculated by steady-state calculation methods. Three aspects of the core component (turbine runner) were optimized\r\nby numerical simulation. All the results were then verified by experiments. It was shown that curved-edge blades are much better\r\nthan straight-edge blades; the optimal blade twist angle is 7Ã?°, and the optimal distance between the runner and the blades is 0.75ââ?¬â??\r\n1.25 times the diameter of the runner. Moreover, the numerical simulation results matched the experimental data very well, which\r\nalso verified the correctness of the optimal results....
The steering stability of vehicle was the most important part of vehicle handling and stability. The stability analysis of vehicle\r\nnegotiating a curve in the plane was studied through simulation.The vehicle dynamics model used in this paper had two degrees\r\nof freedom with nonlinear tire characteristics.When two vehicle state variables, namely, velocity and steering angle, were changed,\r\nthe GA and phase space analysis were used to compute the equilibrium points and analyze the phase space characteristics of\r\nvehicle system. Considering the nonlinear tire characteristic, the working region of tire was figured out and compared, while the\r\nvehicle was under different operating conditions. From the analysis results, it could be concluded that working in the nonlinear\r\nregion of tire characteristic was the ultimate reason of vehicle instability. The knowledge derived from simulation results could\r\ndramatically enhance the understanding of stability of the actual vehicle negotiating a curve on an even surface. Such knowledge\r\nwas a prerequisite for robustly designing the chassis, such as steer-by-wire, which would be the topics of future work....
Numerical investigation of free convection heat transfer in a differentially heated trapezoidal cavity filled with non-Newtonian\r\nPower-law fluid has been performed in this study. The left inclined surface is uniformly heated whereas the right inclined surface is\r\nmaintained as uniformly cooled.The top and bottom surfaces are kept adiabatic with initially quiescent fluid inside the enclosure.\r\nFinite-volume-based commercial software FLUENT 14.5 is used to solve the governing equations. Dependency of various flow\r\nparameters of fluid flow and heat transfer is analyzed including Rayleigh number (Ra) ranging from 105 to 107, Prandtl number\r\n(Pr) from100 to 10,000, and power-law index (??) from 0.6 to 1.4. Outcomes have been reported in terms of isotherms, streamlines,\r\nand local Nusselt number for various Ra, Pr, ??, and inclined angles. Grid sensitivity analysis is performed and numerically obtained\r\nresults have been compared with those results available in the literature and were in good agreement....
The elastic stress field for multiple ellipsoidal inhomogeneous inclusions in one of two perfectly bonded semi-infinite solids\r\nsubjected to external stress is investigated by the modified equivalent inclusion method. Using the general solution for the\r\ninhomogeneous inclusion in bimaterial expressed in terms of Garlekin stress vectors, the potential functions necessary to solve the\r\nproblem are obtained.The elastic field induced by multiple inclusions in dissimilar media could be found from the superposition\r\nof the separate solutions of individual precipitate.The effects of the planner interface with parameters of depth from the interface\r\nand both pairs of elastic moduli and also shapes of the inclusion on the solution are given as numerical example, which is of great\r\nsignificance in physical applications....
Grayscale-weighted centroiding weights the pixel intensity to estimate the center of a circular image region such as a\r\nphotogrammetric target or a star image. This is easy to realize with good robustness; however, locating accuracy varies with weight.\r\nThere is no conclusion as to the relationship between weight and centroiding accuracy. To find this relationship and thus acquire\r\nthe highest achievable accuracy of centroiding, one must first derive the general model of centroiding as follows. (1) Set weighting\r\nas a function that includes the grayscale intensity of each pixel and two undetermined parameters ?? and ??. The centers were\r\ncalculated from the new weights. (2) Design an accuracy evaluation method for centroiding based on a virtual straight-line target\r\nto obtain the accuracy of centroiding with various parameters. With these parameter values and accuracy records, the accuracyparameter\r\ncurve can be fitted. In the end, simulations and experiments are conducted to prove the accuracy improvement of this\r\nvariable-weighted grayscale centroiding compared with traditional centroiding. The experimental result shows that the parameter\r\n?? contributes significantly to accuracy improvement.When ?? = 1.5, locating accuracy is 1/170 pixels. Compared to centroiding and\r\nsquared centroiding, the new locating method has a 14.3% and 10.6% accuracy improvement indicating that it improves locating\r\naccuracy effectively....
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