Current Issue : April - June Volume : 2016 Issue Number : 2 Articles : 6 Articles
Polishing process is one of the most critical manufacturing processes during a metal part production because it determines\nthe final quality of the product. Free-form surface polishing is a handmade process with lots of rejected parts,\nscrap generation and time and energy consumption. Two different research lines are being developed: prediction models\nof the final surface quality parameters and an analysis of the amount of material removed depending on the polishing\nparameters to predict the tool footprint during the polishing task. This research lays the foundations for a future automatic\nconformal polishing system. It is based on rotational and translational tool with dry abrasive in the front mounted\nat the end of a robot. A tool to part concept is used, useful for large or heavy workpieces. Results are applied on different\ncurved parts typically used in tooling industry, aeronautics or automotive. A mathematical model has been developed\nto predict the amount of material removed in function of polishing parameters. Model has been fitted for different abrasives\nand raw materials. Results have shown deviations under 20% that implies a reliable and controllable process.\nSmaller amount of material can be removed in controlled areas of a three-dimensional workpiece....
This article details how to control light emitting\ndiodes (LEDs) using an ordinary desktop computer. By\ncombining digitally addressable LEDs with an off-the-shelf\nmicrocontroller (Arduino), multiple LEDs can be controlled\nindependently and with a high degree of temporal, chromatic,\nand luminance precision. The proposed solution is\nsafe (can be powered by a 5-V battery), tested (has been\nused in published research), inexpensive (âË?¼ $60 + $2 per\nLED), highly interoperable (can be controlled by any type of\ncomputer/operating system via a USB or Bluetooth connection),\nrequires no prior knowledge of electrical engineering\n(components simply require plugging together), and uses\nwidely available components for which established help\nforums already exist. Matlab code is provided, including\na ââ?¬Ë?minimal working exampleââ?¬â?¢ of use suitable for use by\nbeginners. Properties of the recommended LEDs are also\ncharacterized, including their response time, luminance profile,\nand color gamut. Based on these, it is shown that the\nLEDs are highly stable in terms of both luminance and\nchromaticity, and do not suffer from issues of warm-up,\nchromatic shift, and slow response times associated with\ntraditional CRT and LCD monitor technology....
In this study, the thermo-elastic effects of frictional heat generation in a disc brake system due to\nbraking actions were simulated. The mathematical model that defined the problem was developed\nfrom the kinetic and potential energies of moving vehicles on the gradient surfaces. This problem\nwas solved for the selected geometry of disc brake and pad with their material properties selected\nfrom existing literatures using the finite element method and the computational results were obtained.\nThe thermal deformation obtained was in good agreement with similar literature results.\nAlso, for the same braking period and conditions, the results showed that a vehicle ascending a hill\ngave a higher temperature rise, Von Mises stress and thermal deformation on brake contact surfaces\nthan when descending hill. Therefore, the braking period required to bring a moving vehicle\nin ascendent motion to a lower speed is expected to be shorter because of the gravity effect than\nhorizontal motion, while descendent motion requires longer braking period....
Communication networks have undergone rapid developments in the past few decades in many\nSub-Saharan African countries. The increasing number of subscribers and demand for greater variety\nof services in these countries make it difficult for network operators to provide the service\nvarieties subscribers want while maintaining acceptable levels of quality of service. This paper\nanalyzes the radio network of cellular networks in terms of traffic distribution over the existing\nnumber of communication channels using MATLAB/Simulink. A scale-free user network, which\ntakes into account user behavior in a realistic physical network, has been used to model a more\nrealistic cause for call blockings in a typical cellular network deployment under a Sub-Saharan\nenvironment. Peak recorded traffic distribution was observed to have overwhelmed the existing\nnumber of channels provided by the network operators for some cells eventually leading to increase\nin call drop rates. This high call blocking probability was attributed to poor network monitoring\nby the network operators to match the ever changing traffic intensities....
In the first part of the paper the power consumed to overcome the viscous friction between the rotors and the\ncase in case of a rotating volumetric pump is calculated. An experimental stand used to test this new type of\nvolumetric pump with rotors profiled is presented; the power at the working machine couple is determined\nand an energy balance of the installation is issued....
The smart grid refers to next generation power grids, with multi-directional flows of electricity and information to make a wide distributed network. Through smart grid, the power system becomes smart by communicating, sensing, control and applying intelligence. For ideal system, the smart grid technologies are more compatible to permits many functions which can optimize with the combination of the use of bulk generation and transmission. The Smart grid is also kept the environment free from pollution; minimize the cost, effective operations, against all types of hazards and danger. In this review, we discuss the smart grid technology, its standard and recent challenges. We explore the different projects of the smart grid in developed countries and discuss the implementation challenges for undeveloped countries...
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