Al-Qadisiyah Journal for Engineering Sciences

Micro-EDM is one of an important process in machining holes which is used in wide applications to fabricate medical devices and small dies.20 samples were run by using CNC EDM machine was used for machining of conducting materials such as copper alloy workpieces for tap water dielectric by supplied DC current values (4, 6 and 10A), gap distance (0.3, 0.4 and 0.5mm) and machining time (5, 7 and 10min). Voltage of (70V) was used to cut 0.7mm thickness of copper (Cu) alloy workpieces to obtain the micro holes (400, 300, 210, 200, 120, 100, 85, 75, 70) μm.
The present work demonstrates the optimization process of hole diameter producing using electrical discharge machining (EDM) by RSM (Response Surface Methodology). The current, gap distance and machining time were the control parameters of EDM. RSM method was used to design the experiment using a second–order response surface. The process has been successfully modeled using RSM and model adequacy checking is also carried out using Minitab Software. Finally, an attempt has been made to estimate the optimum machining conditions to produce the best possible responses within the experimental constraints.

During the last few decades, anthropogenic activities have dramatically attired the quality of surface waters including those of rivers. The rising level of pollutants and changes in mid stream water quality of Ganga River have received serious attention of scientist and policy makers in India. The present investigation was attempted to study water quality of River Ganga and to record the qualitative change in water if any during the three consecutive months of sampling in 2013. A systematic study has been carried out to assess the water quality of River Ganga in Varanasi city. 36 water samples from four sampling stations i.e. By pass bridge upstream, Assi Ghat, Dashswamedh Ghat, and Raj Ghat bridge downstream, were collected and analyzed for physico-chemical parameters (Temp, pH, hardness, total dissolved solids, dissolved oxygen, B.O.D., and free CO2) .The analytical data of various physicochemical parameters indicates that some parameters like pH, hardness and total dissolved solids are found to be in excess than the prescribed limit in some water samples of the study areas as compared to World Health Organization standards (WHOS).

Some manufactured material properties are expected to have unavoidable shifting in its average value for many reasons, however, they are still able to meet the established specifications. This case occurs when the standard deviation of the process at the various average values is very small compared to the difference between the upper and lower specification limits. On the other hand, any results out of these limits indicates that the efficiency of the process changes and the reasons have to be investigated and corrected .In this study, Al-Qadissiyah brick factory was adopted to examine the acceptance of the produced brick, in terms of its dimensions, according to Iraqi specifications. Control charts were plotted for this purpose. Two types of charts were used, the mean and the standard deviation charts. The upper and the lower limits (UCL andLCL) of each brick dimension were plotted and discussed. The results showed that the lower, the upper limits and the mean value for all dimensions are within the IQ specifications limits and the process is under control. However, the results of the length show that there is one point outside the LCL at the mean chart and one point outside the UCL at the standard deviation chart. This due to the chance causes, as it is only one point from thirteen patches .These charts can be adopted by the factory to show the production process and can be used in the future to investigate the mean of any measured patch.

In this study, effect of high temperature on the compressive and flexural strength of concrete used crushed clay brick as coarse aggregate were studied and compared the results with concrete containing normal coarse aggregate as a control mix. The replacement of normal coarse aggregates in concrete mixes was done at 0%, 50% and 100% by volume for concrete mixes with crushed clay brick as coarse aggregate. Concrete specimens were heated up to temperatures20oC, 100oC, 200oC, 300oC, 400oC and 500oC. Samples were allowed to cool down naturally to room temperature. After that, the maximum compressive and flexural strength were evaluated for each temperature above. Three samples were tested for each temperature. The compressive and flexural strength of concrete containing 100% of crushed clay brick as vcoarse aggregate gradually decreased (small loss) for all temperature increments compared with other two concrete mixes used (0% and 50%) by volume of crushed clay brick as coarse aggregate. However replacing 50% of normal aggregates with lightweight aggregates (crushed clay brick) by volume did not have a significant effect on the compressive and flexural residual strengths.

In this article experimentally investigations have been carried out to study the effect of the size and type particles on the thermal conductivity of micro and nanofluids. The study investigated nanofluids and microfluids which containing silver (Ag) and zirconium oxide (Zr2O3) as well as in the size and type of micro and nanoparticles in distilled water as base fluid with different particles size and concentrations. The experimental results emphasized the enhancement of the thermal conductivity due to the nanoparticles presence in the fluid greater than microfluids, also shown the effect of the particle size and concentration on the thermal conductivity. It has been recognized that the addition of highly conductive particles can significantly increase the thermal conductivity of heat – transfer fluids. Particles in the micro and nano – size range have attracted the most interest because of their enhanced stability against sedimentation and, as a result, reduction in potential for clogging a flow system. Furthermore the results showed that, the obtained thermal conductivities doubtlessly revealed that size and type particles was a key factor affecting conductive heat transport in suspensions. The aim of this article is an experimental exploration of the thermal conductivity of micro – and nano – particles and Compared with them as well as type particles and the method used in this researcher know Lee's disc technique. These results show noticeable enhancement in the thermal conductivity were evaluated to be ( 7.66 %, 2.35 %) for the Ag, Zr2O3 – distilled water nanofluid while reaches to (3.23 %,1.02 %) for the Ag , Zr2O3 – distilled water micro fluids at the concentration of (0.05 vol. %) and at the room temperature. A good agreement was found between the experimental obtained data for this paper and other results from published papers.

The present work is a theoretical study of the direct contact condensation process of saturated vapor on fully developed subcooled laminar liquid film flowing over thin liquid film on adiabatic and the inclined solid surface .A theoretical model based on momentum , continuity and energy equations . heat balance and thermal energy equation is developed to get approximate solution to describe the condensation performance of vapor on a thin liquid film . The obtained equations of solution are solved numerically using Runge-Kutta method and then plotting and the variation of must important parameters such as ; Reynolds , Prandtl , subcooling numbers and shear stress on the values of film thickness layer , bulk temperature , Nusselt number (heat transfer coefficient) and velocity of the flow . The result of variation shows that the major effect parameters is attributed to the Peclelt & Subcooling numbers , while the other parameters is less significant .

This paper studies the utilization of fuzzy logic on pattern recognition sender after analyzing unknown pattern converged from associative. In order to specify the original patterns stored in memory. Results indicated that the addition of fuzzy stage to Hopfielf net to identify the unknown pattern called (FRS) was succeeded in differentiating and identifying unknown patterns were produced by “Hopfield neural network associative memory “(HNMAR) despite of the increasing in signal corruption to relatively high levels. It was demonstrated the possibility of rising the level of performance of memory type “Hopfield” where the signal corruption is at relatively higher percentage.