In this work a study and calculation of the normal approach between two bodies,
spherical and rough flat surface, had been conducted by the aid of image processing
technique. Four kinds of metals of different work hardening index had been used as a
surface specimens and by capturing images of resolution of 0.006565 mm/pixel a good estimate of the normal approach may be obtained the compression tests had been done in strength of material laboratory in mechanical engineering department, a Monsanto tensometer had been used to conduct the indentation tests. A light section measuring equipment microscope BK 70x50 was used to calculate the surface parameters of the texture profile like standard deviation of asperity peak heights, centre line average, asperity density and the radius of asperities. A Gaussian distribution of asperity peak height was assumed in calculating the theoretical value of the normal approach in the elastic and plastic regions and where compared with those obtained experimentally to verify the obtained results.
Based on the streamer growth model, the streamer discharge propagation was simulated in aid of finite element technique. That was done within two non- mixed dielectric liquids (Normal-Hexane and Acetone) located between two electrodes in pin - plane configuration. The output results show that, the path of the streamer was affected by the interface between the two liquids; the streamer path crosses this interface under some conditions such as the permittivity of the liquids and the distance between this interface and the tip of the pin. Under other conditions, the streamer path grows along the interface. The results were assisted by the development of the potential and the electric field distributions with the growth of the streamer propa
... Show MoreThis paper presents the implementation of a complex fractional order proportional integral derivative (CPID) and a real fractional order PID (RPID) controllers. The analysis and design of both controllers were carried out in a previous work done by the author, where the design specifications were classified into easy (case 1) and hard (case 2) design specifications. The main contribution of this paper is combining CRONE approximation and linear phase CRONE approximation to implement the CPID controller. The designed controllers-RPID and CPID-are implemented to control flowing water with low pressure circuit, which is a first order plus dead time system. Simulation results demonstrate that while the implemented RPID controller fails to stabi
... Show MoreTable tennis is considered one of the fast base sports that the player needs to have the speed of performance and awareness, especially in straight forward and back strikes, which is an important offensive skills, and the player success depends on his perception speed to the point of the fall of the ball in the arena of his competitor. But there is no way to measure cognitive processing speed. Therefore, the researchers sought to design a test that measures this ability to ensure its scientific evaluation, and then establish standard scores for this test for the players of the specialized school of table tennis, to help evaluate them objectively and move away from subjective estimates when evaluating and developing measuring instruments in
... Show MoreAccess to high-quality neurosurgery online learning is limited in low- and middle-income countries, and Iraq is part of this category. The need for collaboration and connection of people worldwide to exchange ideas and experiences in neurosurgery is a challenge. Surgical Neurology International® (SNI)/SNI Digital stimulated the establishment of the joint effort to bring the discussion about the best experiences in neurosurgery from the United States and Iraq together in an internet meeting format.
An online survey was formulated and distributed to the attendees of the SNI-Baghdad neurosurgery
Background: Spleen is a hemopoietic organ which is capable of supporting elements of different systems. It is affected by several groups of diseases; inflammatory, hematopoietic, reticuloendothelial proliferation, portal hypertension and storage diseases. Ultrasound (US) may detect mild splenomegaly before it is clinically palpable. Knowledge of the normal range of spleen size in the population being examined is a prerequisite. Racial differences in splenic length could result in incorrect interpretation of splenic measurements and such differences would make it difficult to standardize expected splenic length and to determine non- palpable splenic enlargement.Objectives: To measure the normal values of splenic lengthin Iraqi subjects an
... Show MoreCalculations of sputtering yield for Lithium,Sodium and Krypton bombarded by the same own ions are achieved by using TRIM program.The relation of angular dependent of sputtering yield for each ion/target is studied. Also, the dependence of the sputtering yield of target on the energy of the same ion is discussed and plotted graphically. Many researchers applied polynomials function to fit the sputtering data from experimental and simulation programs, however, we suggest to use Ior function for fitting the angular distribution of the sputtering yield. A New data for fitting coefficients of the used ion/target are presented by applying used function for the dependence of the sputtering yield on the ion energy.
Frictional heat is generated when the clutch starts to engag. As a result of this operation the surface temperature is increased rapidly due to the difference in speed between the driving and driven parts. The influence of the thickness of frictional facing on the distribution of the contact pressure of the multi-disc clutches has been investigated using a numerical approach (the finite element method). The analysis of contact problem has been carried out for a multiple disc dry clutch (piston, clutch discs, separators and pressure plate). The results present the distribution of the contact pressure on all tShe surfaces of friction discs that existed in the friction clutch system. Axisymmetric finite element models have been developed to ac
... Show MoreIn the present work, the behavior of thick-walled cylinder of elasto-plastic material (polymeric material) has been studied analytically. The study is based on modified Von-Mises yield criterion (for non metallic material). The equations of stress distribution are obtained for the cylinder under general cases of elastic expansion, plastic initiation and elastic-plastic expansion.
A computer program is developed for evaluating the stress distribution. The solution is carried out for worst boundary conditions when the cylinder is subjected to the combination of pressure load, inertia load, and temperature gradient.
The results are presente
... Show MoreIn this research, CNRs have been synthesized using pyrolysis of plastic waste(pp) at 1000 ° C for one hour in a closed reactor made from stainless steel, using magnesium oxide (MgO) as a catalyst. The resultant carbon nano rods were purified and characterized using energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD). The surface characteristics of carbon rods were observed with the Field emission scanning electron microscopy (FESEM). The carbon was evenly spread and had the highest concentration from SEM-EDX characterization. The results of XRD and FESEM have shown that carbon Nano rods (CNRs) were present in Nano figures, synthesized at 1000 ° C and with pyrolysis temperature 400° C. One of t
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