Mechanical Engineering

In this paper, we model the arc welding process by ANSYS software, the defects of weld joints is discussed. Ultrasonic techniques have been used for this purpose. An integrated comprehensive 3D model has been developed to study the transport phenomena in welding.. This includes the arc plasma, droplet generacoppertion, transfer and impingement onto the weld pool, and weld pool dynamics. Ultrasonic Testing (UT) uses high frequency sound waves to conduct examinations and make measurements. In this paper, T-shaped junction has been modeled in the software environment. The circuit model of an element is used to simulate carbon steel. UltraSonic attachment method has been studied. The optimization model is derived.

Milling operates on the principle of rotary motion. A milling cutter is spun about an axis while a workpiece is advanced through it in such a way that the blades of the cutter are able to shave chips of material with each pass. Milling processes are designed such that the cutter makes many individual cuts on the material in a single run; this may be accomplished by using a cutter with many teeth, spinning the cutter at high speed, or advancing the material through the cutter slowly. Most often it is some combination of the three.

The goal of this paper is to design and implementation of wearable device which can be use as a guide to blind people by allowing them to imaging and response to spatial information by using IR transceiver then give an alarm as a vibration to skin by using a mobile vibrator. This vibration is give alarm to blind person to avoid obstacle, its look like sensory appendages of insects. This device can be used instead of dogs or cane to help blind people also it can be used by workers whose work in dangerous construction locations.

In this study, the entropy generation of a fully developed laminar flow in circular segment ducts with constant wall heat flux is investigated. Entropy generation is obtained for various segment angels (2?), various wall heat flux and various Reynolds number. It is concluded that segment angel and wall heat flux have considerable effect on entropy generation. For the increasing value of these parameters, both entropy generation and pumping power ratio are increased at fixed Reynolds number.

In this paper analytically investigated the effects of water–Al2O3 nanofluid on the entropy generation through a coiled tube heat exchanger under uniform wall temperature condition in laminar regime. Nanofluid thermo-physical properties are obtained from literature or calculated from suitable correlations. It is found that adding nanoparticles improves the thermal performance of water-Al2O3 flow and with increasing volume constriction of nanoparticle, total entropy generation at fixed Reynolds number, decreases. By increasing , entropy generation decreases, also with increasing , total entropy generation increases.

In this paper, the entropy generation of a fully developed laminar flow in annularsector ducts with constant wall heat flux is investigated. Entropy generation is obtained for various aspect ratio (?), various sector angels (2?), various wall heat flux and various Reynolds number. It is found that with the increasing aspect ratio (?) and sector angels (2?) values, total entropy generation and pumping power at fixed Reynolds number increases and with increasing wall heat flux values, total entropy generation increases, however, pumping power decreases.

This paper analytically examines the effects of adding nanoparticles on the exergy destruction of water– Al₂O₃ nanofluid flow through a circular duct under constant wall heat flux for thermally and hydrodynamic laminar regime. The single phase model is employed to simulate the nanofluid convection, taking into account appropriate thermophysical properties. Particles are assumed spherical with a diameter equal to 13 nm and are easily fluidized. In this approach, nanofluid can be treated as a pure fluid. Results show that with increasing the volume concentration of particles, the values of both of exergy transfer and heat transfer rate, decreases, especially for lower values of Reynolds number. These results indicate that along the duct at a fixed volume concentration, exergy destruction, decreases.

Evaluation of 20 min. shot peening surface treatment on fatigue strength of 6063-T6 Al allay is presented under 3.5% NaCl solution from one day, one week and one month under room temperature and stress ratio R= -1. The results show that the shot peening has strong effect on the fatigue strength at 107 cycles for corroded specimens. In case of shot peening ,only 17.5% loss in fatigue strength even after submerging for one week compared with 60% of the fatigue strength was reduced in case of un shotted specimen . But for one month pre – corroded specimens, the fatigue strength was reduced by 64% in corrosion environment while shot peening improved the above reduction to be about 44%.

The industrial/military power of any nation is attributed to its ability to produce steel. Alloys are as a result of the combination of a base material with other constituent elements. It is therefore interesting to note that for this well researched paper metallic alloys are a combination of a base metal and other constituents. The main constituents here are the carbon. It is the addition of carbon that change metals to an engineering material, thus, various constituents of carbon carbides can be constituted to give different categories of steel alloys which can be used to produce different spare parts. With various production methods, these steel alloys can be better appreciated by what it can be used to accomplish.

Metal-joining plays an important role in the industry and virtually all servicing and manufacturing concerns, directly and indirectly, benefit from it. However, not all kinds of joining processes are suitable for thin metals and light works due to the sensitivity of light metals to heavy heat, rapid corrosion of most metals at high temperatures and very high quantities of heat energy needed to fuse parts. It has been observed that the heat energy required to melt and establish continuity across parts is even higher with welding and brazing-which utilize fillers of high tensile strengths and melting points-such as iron (0.8% steel-800 MNM-e 1535oc), copper (210 MNM-z 10-83oc) and silver (125MNM-e 961oc). In this study, therefore the cold-brazing Joining technique which does not utilize heat in its operation, was studied using experimental designs. Light copper wires of about 0.01mm diameter, zinc electrode and concentrated zinc tetraoxosulphate (vi) solution (Zn2So4) were used and, results from the investigation and calculations show that thin metals and light parts can be easily joined using cold-Brazing joining technique with energy consumption for depositing a zinc filler of 1kg using high temperature process and the same amount of zinc filler using cold-Bracing, in the ratio of 71:269 KJ. Thus, it is certain that other electrolytically depositable metals with higher tensile strengths and melting points than silver-solders and brass, such as copper, can be used with this technique. And if fully made better, the present innovation will not only rival, but surpass most joining methods.