Engineering and Technology Journal

In this research, a thermal insulation between the two layers of a wall has been used for the residence buildings to reduce the heat transmitted across the walls and thus reducing the power consumption for cooling load. A MATLAB program was used to obtain the thermal response for various types of walls from the energy sources (solar radiation and ambient temperature) in summer season in Baghdad, Iraq. Local materials used in this study as thermal insulators between the two layers of walls are: local cane mat, wood sawdust and cork grains. Modeling tests were carried out on June, July and August via using Matlab program. The simulation results obtained have been compared for five different types of walls are: usual wall, thick wall, wall containing local cane mat, wall containing wood sawdust and wall containing cork grains, which helps in finding the heat flow across the wall where boundary conditions varied according to solar radiation and environment thermal load. The results showed that using the walls containing of local cane mat, wood sawdust and cork grains can reduce the heat gain by 50%, 44% and 40% respectively, compared with usual wall and thus reduce the power consumption.

This work was designed to examine the effect of various thermosyphon diameters and working fluids on the thermosyphon performance. A thermosyphon made from copper tubes with three different external diameters 7, 13 and 22mm with thickness of 1mm is used in this work. The length of evaporator and condenser were 120 and 300 mm respectively. Working fluids were water, acetone and Freon R11 working fluids are tested. The obtained results have shown that the temperature gradient was decreased when increasing the thermosyphon diameter. Also, the results showed that the Merit for water had the highest value than the other working fluid at the operating range of temperature. The results were shown the heat dissipation by the thermosyphon increased when increasing the thermosyphon diameter for all working fluids. Also the heat dissipation from the thermosyphon with working fluid of water had a highest value of heat dissipation than the others working fluids. The percentage decreased in the temperature gradient by using thermosyphon with diameter of 22mm for water, acetone and Freon R11 were 73.53 %, 68,53 % and 52.35 % respectively compared with that without using thermosyphon.

The coupling effect of coating and inhibition has been investigated in the present work. polypyrrole coating with adding coumarin was applied on carbon steel to protect it against corrosion. Electropolymerization process by cyclic voltammeter was carried out in 0.2M oxalic acid electrolyte containing 0.1M pyrrole monomer without and with 0.01M coumarin as an eco-friendly inhibitor. SEM/EDS, AFM and FTIR techniques were used to identify the coating film. Corrosion test using Potentiostat was achieved for uncoated and coated specimens and the results indicated that the corrosion potentials became nobler compared with uncoated specimen, this means that the anodic sites were covered by undoped and doped PPy film as illustrated from the deceasing of anodic and cathodic Tafel slopes. Protection efficiencies were acceptable and good (71.46% for PPy film and 77.47% for coumarin/PPy film). The polarization resistance was increased from 0.114 Ω.cm2 for uncoated C.S. to 0.176 and 0.404 Ω.cm2 for PPy coated and coumarin/PPy coated C.S. While the porosity percentage was 0.44% and 4.50 for PPy coated and coumarin/PPy coated C.S. due to increasing the roughness of coumarin/PPy film.

The main goal of this work is to enhance the Voltage stability by using optimum location and parameters setting of STATCOM device. The parameters are the magnitude of the output voltage and the angle , these parameters are taken to control the device performance. The simulation results have been done by using power flow program solution by Newton-Raphson method (Matlab program / M-file) with Particle Swarm Optimization (PSO) technique, for power losses minimizing and improving voltage profile. Two systems have been implemented:- IEEE 5-bus test system and Iraqi (400 kV) National super Grid System 27-bus. The MATLAB programs are Applied in the first step on IEEE 5-bus test system to examine the performance of the programs by comparing the results with other references, then it is implemented on Iraqi (400 kV) National super Grid System to find optimum location and parameter setting of STATCOM device. The results show that, the STATCOM has significant effect on improving the voltage profile and reducing apparent power losses, The STATCOM device performance depends on its location and parameter settings, and The PSO algorithm can easily find out the optimal location and parameters setting of the STATCOM for which the voltage deviation are minimum.

This study investigated the types and profile of defects facing newly constructed houses through conducting a survey and analyzing defect records of data observed for 652 houses out of 1000 houses newly constructed for Salahaddin University academic staff in Erbil City. The result of analysis revealed that the overall of 6758 defects identified with the mean average of 10 defects per house. The overall percentage of defected houses for each type of defects and the location of the defect ranged from 10% to 67%. The most defected components found in the doors and windows, which comes in rank 1 with the highest percentage of defected houses reached to 76%, whereas coating and painting of doors come in rank 2 with percentage of 75%, and cracks in structural elements come in rank 3 with 73%. Analyzing the defects in terms of area and location showed that the finishing works representing the major defects area of 48%. While, the defects in the doors and window representing second highest defects of 42%. The results indicated that the quality performance in newly constructed houses is low due to poor workmanship and lack of experience and skills of construction staff and inadequate supervision.