Engineering and Technology Journal

Electrochemical machining (ECM) is an advanced machining process belonging to electrochemical category. Where in the material removal takes place by anodic dissolution of work piece in an electrolytic solution. This research presents results of the Electrochemical Machining (ECM) process, which was used to remove metal from the internal hole of the work piece (pure Zinc) by brass tool in an aqueous solution NaCl solution. The experimental study the effect of (ECM) process parameters such as (Current density, Gap distance, Electrolyte concentration) on Metal Removal Rate (MRR) and particle size of (Zinc oxide) sludge waste that precipitate from ECM. X-ray diffraction pattern for the resultant powder shows well-crystallized Zinc oxide powder The results indicated that particle size decreases from (82.432 to 24.6μm) and enhancement of MRR by (58.15%) with increasing current density. The increasing in gap distance between tool and work piece from (0.5 to 1.5) mm causes increasing in particle size from (76.451 to 91.81) μm and decrease (MRR) to (11.07%). For electrolyte concentration increasing from (100 to 300 g/l) leads to decrease in particle size from (89.218 to 32.406) μm, while improvement in MRR by (4.83%).

The aims of this study is to investigate the resistance of different SCC mixtures to aggressive solutions. The investigation included the type of the cementitious materials (silica fume and high reactivity Attapulguite-HRA) and limestone powder (chalk powder and Al-gubra). The powder content of the mixes was kept constant, 500 kg/m3. The slump flow, L-box, and V-funnel were performed for mixes in there fresh state. In the present work, the specimens were immersed in sulfuric acid solution with a concentration of 0. 5% up to 289 days after normal curing for 28 days. After concrete has hardened, two types of test are performed. Firstly, destructive tests are conducted including (compressive strength, splitting tensile strength, and modulus of rupture). Secondly, a mass loss as non-destructive test is performed. The results obtained from this work, show that concrete mixes with chalk powder only, had the best resistance to sulfuric acid solution comparable with concrete made with Pozzolanic materials the reduction in compressive strength was 25. 9 %. In addition, concrete mixes with HRA had the worst resistance.

The paper explain an experimental study to show piled raft system behavior when embedded within gypseous soil in three different stats (dry, socking for 1 day and placing a bearing layer of dense sand below the gypseous soil when socking for 1 day). A small-scale “prototype” model of steel box with dimension of (60cm length x 60cm width x 75cm heights) was used for carried out the model tests. Two different lengths of reinforced concrete pile models (40cm and 45cm) of 2.0cm dia. were used to keep the same imbedded length ratio during testing piled raft and piles only. Three different configurations of pile groups (single, three and six piles) were tested in the laboratory in two ways, first; the raft does not contact with the soil and the second; the raft is in contact with the soil. In dry state, the gypseous soil showed a very high carrying capacity with reduction in settlement. Piled raft foundations show an efficient in dry state, where the load carrying capacity increased and the settlement decreased. The improvement ratios in the load carrying capacity were about 16% for single piled raft and 39% for group of three-piled raft, while settlement reduction ratios were about 18% for single piled raft and 45% for group of six-piled raft. When the gypseous soil socked with water for 1 day, the ultimate bearing capacity of foundations is generally reduced by about (69%-83%) compared with dry state for all model configurations. The improvement ratios in ultimate bearing capacity due to using piled raft in soaking state was about (11% -50%) whilst the reduction settlement ratios was about (16% -44%).

In this research, patch was printed on a rectangular radiating substrate Taconic material. The Taconic material used is TLY-5 of 30 x 30 mm2 dimensions and 1.575 mm thickness. Its Relative dielectric constant (εr) of 2.2 was taken in this research. The rectangular radiator of the proposed design was notched with two-step notches. These notches were cut at the bottom of the slotted patch with three similar dimensions slots. A transmission line feeder feeds the patch with a gap between the printed ground plane and the radiated patch. The proposed antenna design has been simulated and tested using CST microwave studio software and a network analyzer with anechoic chamber respectively. The measured and simulated results demonstrated that the proposed shape of antenna design achieved a very wide of operating impedance bandwidth starting from 3.5 GHz up to 12 GHz at return loss (S11) bellow -10 dB at 0.25 mm size of feed gap. The effects of three feed gap different values and the step notches are illustrated in this paper. The radiation measured and simulated patterns were obtained for omni-directional radiation to be suitable for several users.

In this research, study some physical and mechanical properties of polymernano composites. The polymernano composites based on unsaturated polyester resin reinforced with carbon fibers (C.F). The samples are attended by hand lay – up method. The samples constituent were polyester resin as matrix with 3% volume fraction from carbon fiber and (0.5%, 1%, 1.5%, 2 %( volume fractions of carbon nanotube. The water absorption, hardness (shore D), flexural test, impact test and toughness fracture properties are studied. Results showed that water absorption increase with addition 3% volume fraction of carbon fiber and Carbon Nanotube, the sample (polyester+3%C.F+0.5% CNTs) has lower water absorption than other samples. The hardness (shore D), flexural test, impact testand toughness fracture for the sample (polyester+3%C.F+0.5% CNTs) has higher value for Nano- composites.

In this work, an Optimal Linear Quadratic (LQR) and optimal Minimax controller is proposed for Wing Rock Motion Control in Delta wing Aircraft model. The nonlinear Wing Rock Motion dynamics were considered. The LQR and Minimax controllers are designed in order to reduce the Wing Rock Motion. Simulations are performed in order to verify the ability of both controllers to reduce the wing rock motion in delta wing aircraft. Results were plotted together in order to show the difference of performance for both controllers for a comparative point of view.

This research is a part of an experimental study to examine the effect of lap splicing tension steel bars reactive powder concrete (RPC) beams under repeated loads. Eight RPCbeams whose tension steel bars were spliced at mid-span for a length equals 20 times the bar diameter and one RPC beam without lap splice were casted and tested. These beams were simply supported and tested up to failure under the action of two point repeated loads. The studied parameters were: the steel fiber volumetric ratio (1.5%,1.75% and2%), diameter of tension steel bars (12mm, 16mm and 20mm) and the repeated loading regime in which three types of loading were used depending on the minimum to maximum ratio of the applied load. The first loading regime with ratio of 0% with 0 kN for the minimum load while the maximum was the load beyond that causes yielding of steel bars and this is determined from the previous monotonic load test. The second type with 27% ratio (30 kN for the minimum and 105-110 kN for the maximum). The last type was with 20% ratio (the minimum12 kN and the maximum 60 kN).It should be mentioned that 10mm bar diameter was used to the top reinforcement and stirrups for all beams. The mid-span deflection as well as cracks propagation were recorded for each beam throughout the test. The main results showed that the adopted spliced length of tension steel bars was sufficient in monotonic load but insufficient under the action of high number of cycles of the repeated load. In addition, there were beams of splice failure that having low steel fiber ratio or larger diameter of tension steel bars.

This paper proposes a high voltage gain indirect matrix converter to eliminate the voltage degradation problems in AC drive. The proposed converter consists of modified LC-C-LC single-phase bridge rectifier combined with a three-phase Z-source inverter. The combined design of LC-C-LC filter with the single-phase diode rectifier is able to step up DC rectified voltage greater than peak AC input voltage without the requirement to active switching devices. In addition, it can also reduce the input current harmonics, improve input power factor and reduce reactive power consuming from AC supply. To further increase boost capability of the proposed converter and eliminate the voltage degradation problems, the LC-C-LC rectifier is combined with a Z-source inverter. This combination not only increase the converter’s voltage gain but also reduce the reactive power and converter’s size through using small LC-C-LC and Z-source parameters which consequently increase the system’s efficiency. A new Modified Space Vector Pulse Width Modulation (MSVPWM) method has been proposed in order to dominate the shoot-through duty ratio of Z-source inverter. This method results in reducing the level of harmonic for the output current and increasing the dynamic range of the shoot-through duration. The overall drive system has been simulated and analyzed using a hybrid simulation between OrCAD/PSpice and Matlab/Simulink environments through using SLPS integration platform.

This work presents an improving of the photovoltaic / thermal efficiency by using a solar tracking system (2-axes) and AL2O3 mixed with water as working fluid. An integrated system (PV/T) consists of 36 mono-crystalline solar cell was designed and implemented with cooling water technique utilized copper pipes on the back PV side to flow cooling water at different mass flow rates . A (90) bulbs of (12V, 50W) are connected in series are used to simulate the sun light and controled by (3) AC to AC transformers to give different irradiation arrive up to (1000 W/m2).The (AL2O3) was prepared and added to the water with different concentrations to decrease the temperature of PV and increase the rate of heat transfer to maintain good electrical efficiency and an increase in thermal efficiency.The experimental work has been conducted in (UMPEDAC) / Malaysia. The experimental results indicated that when using two- axes solar tracking system the output power generated was increased from (21.69W) to (30.69W). The power module generated is decreased when the temperature of PV surface increased from (64.05W at 24.7oC) to (39.46W at 79.1oC). It is proved that the temperature of PV surface is rising and that efficiency does not exceed 8%, if there is no water-cooling while under the influence of process cooling water, the efficiency increased to 9.6%. In addition, it founded that the optimum mass flow rat of water was (0.2) L/s. At using nanofluid (AL2O3-water) as a percentage ratios (0.1, 0.2, 0.3, 0.4, 0.5) % at constant mass flow rate (0.2) L/s, the temperature dropped significantly from (79.1oC) to (42.2oC). It is found that an optimum concentration ratio of nanofluid at 0.3% and the electrical efficiency of PV/T was 12.1% while the thermal efficiency was 34.4%.

Hospital efficiency & Productivity analysis, is an important issue in the health economics. Furthermore, the study analyze the efficiency and productivity in the hospitals, from two viewpoints: firstly, Data Envelopment Analysis (DEA) used to measure the relative efficiency of the hospitals with applying (CCR) approach. Secondly, Luenberger Productivity Indicator (LPI) used to measure the change (progress) in productivity of consecutive time periods. The study model has been tested and implemented on four case studies based on changing in inputs and outputs variables, of three hospitals in the study district (Baghdad) to analyze their efficiency, in two years period (2014-2015), with three inputs variables and five outputs variables. The results of using DEA technique shows that Al- Alwaiya Children's hospital only still efficient in four cases, while, other hospitals (Ibn Al- Balady & Fatima Al-Zahraa) change their efficiency by changing the case, then by using LPI technique, the results indicate that the (Ibn Al- Balady) hospital has productivity growth in three cases. The Fatima Al-Zahraa hospital has productivity decline in two cases and has growth in one case only. Finally the Al- Alwaiya Children's hospital has productivity growth in all cases during period (2014 – 2015).

The purpose of this paper is to design and manufacture the electrical laser alarm system to assess the buckling failure of 304 stainless steel column and to estimate the critical buckling load (Pcr) under increasing compressive load without shot peening (WSP) and with shot peening (SP). The evaluation of the critical buckling load (Pcr ) was done experimentally and theoretically for long and intermediate pinned – fixed columns. The experimental results revaled that 25 min. shot peening time (SPT) improved the critical buckling load (Pcr ) by 13.3% - 15.39% improvement percentage (IP) for long columns while 18.51% - 23.07% for intermediates. Also it was observed that reducing the effective length (Leff ) resulting in increasing the effect of 25 min. shot peening time (SPT) and kept constant when effective length (Leff ) larger than 200mm. The difference percentage (DP) obtained from theoretically and experimentally comparison between the critical buckling load (Pcr ) was 33.33 to 41.18 for without shot peening and 23.07 to 33.34 for 25 min. shot peening time (SPT) based on Euler and Johnson theories for both long and intermediate columns. Also it was revaled that increasing the slenderness ratio (S.R) reducing the critical buckling load (Pcr) for both columns and both conditions of testing without shot peening (WSP) and shot peening (SP).

It has been found a linear progression between the panel temperature and its efficiency. A novel cellulose pad arrangement, which is saturated with water, at back surface of photovoltaic panel for cooling has achieved better results. The experimental results showed a reduction in maximum PV panel temperature at using the proposed water cooling system. The average temperature of the PV panel dropped 10.1°C and an increase in average solar panel efficiency about 20.8% during operating time. Then, a comparison between the PV panel results cooling by natural convection and using the proposed water cooling system will reveal the most efficient.

This work aims to protect homes against danger, damage, and any criminal activity using Passive Infrared (PIR) and LASER sensors. Depending on cutting beam that emitted from the laser source or from PIR, there are three cases to warn; the first case (without GSM (Global System Mobile)) to issue a warning aerobically by sound. The second case (with GSM modem and Arduino), will be sent a warning SMS (Short Message Service) directly to the user through GSM Networks. In addition, final case with GSM and Arduino, gives the order to the phone (Nokia 6500) snapped a picture and is sent to the user depending on GSM networking MMS (Multimedia Message Service). The LASER sensor is used to detect any move depending on cutting beam. The PIR is used to detect a human body. In addition, the devise cannot work until activated by the user through the password (to activate protection device) as well as confidential in the same way it is closed. This system is built with open source hardware (Arduino uno 328). Beside to software has been the use of Micro C language in programming microcontroller (Arduino uno 328) addition to Proteus program to simulate the work of Ardino.

The heat transfer coefficient (h), is used in thermodynamics to calculate the heat transfer typically occurring by convection. A simple way to calculate (h) is to define it through the classical formula for convection, the present study includes correlations different natural convection can be used to calculate heat transfer coefficients theoretically for the experimental tests done inside and outside close system. All the results obtained from the experimental tests, theoretical calculations and from the literatures show that, heat transfer coefficients (h) are increasedwiththe temperature increasing. The experimental results for all the tested materials appears that there are similarity for the rules of sequence step in the change of heat transfer coefficient (h) with respect to the thermal conductivity coefficients (k) of these materials, and they are in a row from the highest value to the lowest value; Copper, Aluminum, Steel and Brick respectively for both of (k) and (h). The results show a good accuracy and compatibility of the comparison between numerical results with the present experimental work, also give a good agreement between the present experimental work and the numerical results with the experimental results obtained from literature approved in this study.

Electro discharge machining is major non-traditional operations for cutting the materials due to its suitability and benefits. The experimental work of this paper deals with electrico discharge machining (EDM). A system for machining in this process has been developed. Many parameters are studied such as current, time on and time off. Different current rates are used ranging from (30, 36 and 42) Amp, found that low current gives less material removal rates and good surface roughness. The results showing that maximum MRR is achieved (0.525) mm3/min when machining current (42), time on (150), and time off (50) while good surface roughness (2.11 μm) when machining current (30), time on (50), and time off (25).The level of importance of the machining parameters for surface roughness and material removal rate is determined by using Taguchi design experiments and analysis of variance (ANOVA).