Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 7 Articles
Microlubrication minimizes the exposure of metal working fluids to the machining operators leading to an economical, safer, and\nhealthier workplace environment. In this study, a vegetable oil-based lubricant was used to conduct wear analysis and to analyze\nthe effectiveness of microlubrication during end milling AISI 1018 steel. A solid carbide cutting tool with bright oxide finish was\nused with varying cutting speed and feed rate having a constant depth of cut. Abrasion was the dominant wear mechanism for all\nthe cutting tools under consideration. Other than abrasion, sliding adhesive wear of the workpiece materials was also observed.\nThe scanning electron microscope investigation of the used cutting tools revealed microfatigue cracks, welded microchips, and\nunusual built-up edges on the cutting tools flank and rake side. A full factorial experiment was conducted and regression models\nwere generated for both the sides of tool flank wear. The study shows that with a proper selection of the cutting parameters it is\npossible to obtain higher tool life....
Heat pipe with discrete heat transfer property is often called thermal superconductor because it has extremely large thermal\nconductivity. This special heat transfer property is destroyed by integrating cooling apparatus and further reducing the cooling\npower of a heat pipe cooler. This paper experimentally studied the heat transfer property of heat pipe influenced by integrated\ncooling apparatus. To simplify the investigating process, a home-made square heat pipe with the dimensions of L Ã?â??W Ã?â?? H =\n10 Ã?â?? 10 Ã?â?? 100mm3 was built with two pieces of copper plates and two pieces of glass plates face to face, respectively. The two\npieces of copper plates were constructed with inside walls of capillary structure and the two pieces of glasses were with antifog\ninside walls for observing the inner phenomenon.Moreover, isothermal circulating cooling water was applied outside the heat pipe\ninstead of cooling fin. The results show that heat vapor in the heat pipe is condensed earlier and cannot reach the remote section\nof condenser. In other words, the heat transfer property of heat pipe is destroyed by integrating cooling water. This phenomenon\ncauses the unfavorable cooling power of the heat pipe cooler....
Quantum-dot cellular automata (QCA) suggest an emerging computing paradigm for nanotechnology. The QCA offers novel\napproach in electronics for information processing and communication.QCA have recently become the focus of interest in the field\nof low power nanocomputing and nanotechnology. The fundamental logic elements of this technology are themajority voter (MV)\nand the inverter (INV). This paper presents a novel design with less garbage output and minimum quantumcost in nanotechnology.\nIn the paperwe showhowto createmultipurpose reversible gates. By development of suitable gates in logic circuits as an example,we\ncan combineMFAand HS in one design usingCMVMINgate.We offerCMVMINgate implementations to be used inmultipurpose\ncircuit. We can produce concurrent half adder/subtractor and one bit comparator in one design using reversible logic gates and\nCMVMIN gates. Also, a 2 Ã?â?? 4 decoder from recent architecture has been shown independently. We investigate the result of the\nproposed design using truth table.Asignificant improvement in quality of the calculated parameters and variety of required outputs\nhas been achieved....
An approach to segmenting motion objects and suppressing shadows without background learning has been developed. Since\nwavelet transformation indicates the position of sharper variation, it is adopted to extract the information contents with the most\nmeaningful features based on two successive video frames only. According to the fact that the saturation component is lower in\nthe region of shadow and is independent of the brightness, HSV color space is selected to extract foreground motion region and\nsuppress shadow instead of other colormodels. A local adaptive thresholding approach is proposed to extract initial binary motion\nmasks based on the results of the wavelet transformation. A foreground reclassification is developed to get an optimal segmentation\nby fusion of mode filtering, connectivity analysis, and spatial-temporal correlation. Comparative studies with some investigated\nmethods have indicated the superior performance of the proposal in extracting motion objects and suppressing shadows from\ncluttered contents with dynamic scene variation and crowded environments....
The steady two-dimensional laminar forced convection boundary layer flow of an incompressible viscous Newtonian fluid over\na nonlinearly stretching porous (permeable) sheet with suction is considered. The sheet�s permeability is also considered to\nbe nonlinear. The boundary layer equations are transformed by similarity transformations to a nonlinear ordinary differential\nequation (ODE). Then the homotopy perturbation method (HPM) is used to solve the resultant nonlinear ODE.The dimensionless\nentrainment parameter and the dimensionless sheet surface shear stress are obtained for various values of the suction parameter\nand the nonlinearity factor of sheet stretching and permeability. The results indicate that the dimensionless sheet surface shear\nstress decreases with the increase of suction parameter.The results of present HPM solution are compared to the values obtained in\na previous study by the homotopy analysis method (HAM). The HPM results show that they are in good agreement with the HAM\nresults within 2% error....
Shrinkage behavior is a crucial problem in manufacturing plastic molded gear.This is because it negatively affects the dimensional\nstability and accuracy of the involute profile, aswell as the concentricity, roundness, tooth spacing uniformity, and size of the gear. By\nintegrating the Taguchi robust design, Grey relational analysis, and principal component analysis, we investigated the dimensional\nstability related to the shrinkage of tooth thickness, addendum circle, and dedendum circle of molded gear via the optimization of\nprocessing parameters and glass fiber reinforcement.Theresults revealed that the optimal combination of the processing parameters\nof the molded gear to achieve minimum shrinkage is melt temperature of 260�°C, packing pressure of 60%, packing time of 5 s, and\ncooling time of 30 s. The melt temperature showed the highest comparability sequence among the four key process parameters\nexamined, followed by packing pressure, cooling time, and packing time. Meanwhile, the presence of glass fibers induced higher\ndeviations of tooth thickness, addendum circle, and dedendum circle than those of the unfilled polyamide 6 gears....
The flow characteristic of exhaust system has an important impact on inlet boundary of the turbine. In this paper, high speed flow\nin a diesel exhaust manifold junction was tested and simulated. The pressure loss coefficient of the junction flow was analyzed. The\nsteady experimental results indicated that both of static pressure loss coefficients L13 and L23 first increased and then decreased\nwith the increase of mass flow ratio of lateral branch and public manifold. The total pressure loss coefficient K13 always increased\nwith the increase of mass flow ratio of junctions 1 and 3. The total pressure loss coefficient K23 first increased and then decreased\nwith the increase of mass flow ratio of junctions 2 and 3. These pressure loss coefficients of the exhaust pipe junctions can be used in\nexhaust flow and turbine inlet boundary conditions analysis. In addition, simulating calculation was conducted to analyze the effect\nof branch angle on total pressure loss coefficient. According to the calculation results, total pressure loss coefficient was almost the\nsame at lowmass flow rate of branchmanifold 1 but increased with lateral branch angle at highmass flow rate of branchmanifold 1....
Loading....