KUFA JOURNAL OF ENGINEERING

The process of salt dissolution is a reason of structure severe deformation by effective settlement. This paper investigates the effect of soaking process on the soil samples from site near the Faculty of Engineering at University of Kufa. Four samples (S1, S2, S3 and S4) were taken from different locations near the selected site. These samples were soaked for two weeks' duration then tested with standard Proctor to estimate the change in the maximum dry density with reference one (natural samples). All samples experience an increase in the maximum dry density and this increase varies

This paper studies the influence of oil products )gas oil and gasoline misname benzene) on strength and durability of high strength latex modified concrete. Three percentage (5, 7.5 and 10% by weight of cement) of styrene butadiene rubber latex (SBR) were used in this work to produce Latex Modified High Strength Concrete (LM-HSC). Epoxy protective were used as coating for all test specimens. Three exposure periods of oil products were used 30, 90 and 180 days after 28 days water curing. The experimental program in this research including; compressive strength, weight change, sorpitivity and initial surface absorption tests were performed. Generally the results showed that LM-HSC coated by epoxy has good resistance to the effect of oil products relative to LM-HSC without epoxy coating. The results showed that modification of HSC with latex SBR increased the compressive strength and lowered weight change, initial surface absorption, and longer period taken for the capillary soaking resulted in lesser sorptivity value, and in comparison with the HSC control concrete. All samples sunken in gas oil showed better results than samples sunken in gasoline this may be ascribed to the lesser viscosity of gas oil than gasoline.

In this work, the effect of capillary tube diameter on refrigerator performance is studied for refrigerants R134a, R290, R600a and its mixture which named: RMix1(70%R134a,20%R290,10%R600a), RMix2(70%R134a,10%R290,20%R600a), RMix3.(50%R134a,20%R290,30%R600a), RMix4 (60%R134a,20%R290,20%R600a). The three adopted capillary tubes diameter are 1.4 mm, 1.8 mm and 2.2 mm, named capillary1, capillary2 and capillary3 respectively. The experimental work show that, the refrigerator operates in 2.2 mm capillary tube's diameter with R134a gives the highest COP from other refrigerants with the same diameter, where the performance of refrigerator with capillary tube of 1.4 mm and alternative ozone friendly refrigerant RMix2 give 1.3% COP reduction from base case of R134a .

In the present investigation, erosive wear property of high chromium white cast irons (HCWI) is reported. HCWI were destabilized at two different temperatures of 955oC and 1100°C, air cooling followed by tempering heat treatment at 400°C and 700°C at each destabilized temperature. Erosion damage was evaluated by the removed material mass at impact angle 45° and time of 10 Hours. The surface metal flow was observed. Surface morphology of each specimen was characterized with scanning electron microscopy (SEM). The effect of heat treatment on differences in wear features of specimens is discussed. Experiment showed that the erosion rate of specimen destabilized at 1100°C, air cooled followed by tempering at 400°C air cooling is the best than other treatments. The hardness of test surface by this treatment increased from the initial 57 to 58 HRC after 10 hour. It showed that austenite in the surface structure has been transformed to martensite , which hardened the surface. Similarly, work-hardening effect also occurred on specimen destabilized at 955°C, air cooled followed by tempering at 400oC, air cooling to make its surface hardness increased to 59 HRC. It was shown that HCWI series heat treated at 955°C and 1100°C and tempered at 400°C have a very good erosive wear resistance and they are expected to find wide application as wear-resistant materials.

A forced convection heat transfer in ducts (circular, triangular, rectangular) cross sections and (1m) length with hydraulic diameter (0.1m) filled with porous media (glass spheres 12 mm diameter) is investigated experimentally at constant heat flux from the wall (1070W/m²) with Reynolds number range of (12461-2500). Comparison was made between three ducts for local temperature distribution and local Nusselt number). The experimental results showed the effect of Reynolds number and cross section on the temperature profile and local Nusselt number,also empirical correlations for average Nusselt number and Peclet number were obtained for three ducts.

Power quality improvement of low voltage grid is a great challenge that confronts the sophisticated power applications, because their performance is highly sensitive to the quality of power supply. Dynamic Voltage Restorer (DVR) used widely as an efficient and skillful device to adjust electrical disturbances of the distribution grids. This paper introduces an overview of the components of the 3-phase dynamic voltage restorer and design its own control circuit. The performance of DVR was developed on the basis of the appropriate selection of Photovoltaic (PV) module instead of the present conventional designs. Through this design, the need of series converter (DVR) for the current

The Iraqi kaolin clay was used as a raw material in this research. three mix proportion was applied, (96:4), (93:7) and (90:10) as (kaolin grog: kaolin binding ). The specimens of mortar were burning at 1500ᵒC, after producing a refractory aggregate (grog) by preparation process mixing with sodium silicate solution as adhesive material with 5% by weight of the mix. The mechanical tests were carried (compressive and bonding) strength, durability investigations (thermal shrinkage, and reheating expansion), and the physical investigation was carried (bulk density, specific gravity, apparent porosity and water absorption). It was found the first mix (96:4) recorded the highest compressive strength befor burning and bonding after burning, and the best physical properties after burning at 1500 ºC, with mix proportion (96: 4), while the highest compressive strength after burning were the mix three (90: 10).

Solar chimney power plant is a technology capable to generate electric energy through a wind turbine using the solar radiation as energy source; nevertheless, one of the objectives pursued since its invention is to achieve energy generation during day and night. The ground under the power plant plays an important role on the energy balance and heat transfer, due to its natural behavior as a heat storage system. An experimental model was designed in Holley Kerbala city (Iraq), which consisted of a 3m collector radius with 8ᴼ collector inclination angle and a 6m height of chimney been constructed and collector periphery opening height 3cm. Three kinds of grounds was studied in this work: sand, mixed from sand and pebble and the third is black pebble. The results show that the highest airflow temperature inside the chimney reached was 66.8Co when using the black pebbles basement. The maximum basement temperature measured was 81.6Co for the mixed basement. Also, the highest temperature difference reached was 23.2Co for the same ground that have good performance during day light compared with pebble basement that have more energy saving in night.

Automatic control of automotive engines provides benefits in the engines performance like emission reduction and fuel economy. Due to high dropping in the rotational speed in the presence of load torque and disturbance, which may lead to engine stalling, an electronic control unit (ECU) has to keep the engine speed at the reference idling speed. In this paper, the four strokes, four cylinders, gasoline, port fuel injection engine is studied and a Mean Value Engine Model (MVEM) is used to simulate the nonlinear model of the engine. The problem of preserving the engine speed with minimum settling time, minimum undershoot and minimum overshoot in the presence of load torque or disturbance at idle speed mode is studied. PID-like Fuzzy Logic Control (PID-FLC) with minimum structure is designed to solve this problem. Comparisons among conventional PID controller and fuzzy controller is made. Simulation results of this PID fuzzy controller show good improvement over the conventional PID controller the idle speed response. The simulation results with PIDFC show that the dropping in the engine speed is reduced around (33%) compared with PID controller. The peak overshoot is reduced around (19%) compared with PID controller for the same value of the load torque. The settling time is reduced by (50 %) compared with the PID controller.

In the present work, the influence of thermal oxidation (TO) process on the micro-hardness and wear performances of a pure titanium (Ti) was studied. The process has been carried out at various values of temperature for determined time followed by furnace cooling to room temperature. The TO has supported the development of strong surface film on the Ti without spallation. This surface structure improved the results of micro-hardness and wear compared to untreated samples.

Pavement Condition Index (PCI) is one of the important basics in pavement maintenance management system (PMMS), and it is used to evaluate the current and future pavement condition. This importantance in decision making to limit the maintenance needs, types of treatment, and maintenance priority. The aim of this research is to estimate the PCI value for flexible pavement urban roads in the study area (kerbala city) by using Garber et al. developed model. Based on previous researches, data are collected for variables that have a significant impact on pavement condition. Data for pavement age (AGE), average daily traffic (ADT), and structural number (SN) were collected for 44 sections in the network roads. A field survey (destructive test (core test) and laboratory test (Marshall Test)) were used to determine the capacity of structure layer of pavement (SN). The condition index (CI) output from a developed model was compared with the PCI output of PAVER 6.5.7 by using statistical analysis test. The developed model overestimates value of CI rather than PCI estimated from PAVER 6.5.7 due to statistical test to a 95% degree of confidence, (R = 0.771) for 44 sections (arterial and collector).

This research study the effect of exist of opening in web of deep beam loaded directly and indirectly and the behavior of reinforced concrete deep beams without with and without web reinforcement, the opening size and shear span ratio (a/d) was constant. Nonlinear analysis using the finite element method with ANSYS software release 12.0 program was used to predict the ultimate load capacity and crack propagation for reinforced concrete deep beams with openings. The adopted beam models depend on experimental test program of reinforced concrete deep beam with and without openings and the finite element analysis result showed a good agreement with small amount of deference in ultimate beam capacity with (ANSYS) analysis and it was completely efficient to simulate the behavior of reinforced concrete deep beams. The mid-span deflection at ultimate applied load and inclined cracked were highly compatible with experimental results. The model with opening in the shear span shows a reduction in the load-carrying capacity of beam and adding the vertical stirrup has improve the capacity of ultimate beam load.

This research describes the seepage characteristics of experimental model test of dam with cutoff located at different region (at dam heel, at mid floor of dam, and at dam toe). It is resting on sandy soil with cavity at different locations in X and Y directions (such as in Al-Najaf soil city). Thirty three model tests are performed in laboratory by using steel box to estimate the quantity of the seepage and flow lines direction. It was concluded that the best location of the cutoff wall is at the dam toe for model test with cavity ( Xc/B= 0 and 0.5), but for model test with cavity ( Xc/B≥1), the best location of the sheet pile wall becomes at the dam heel. For negative location of the cavity, the best location of the sheet pile wall is at the middle of the floor dam.

The production process of a triangle cup is very difficult method, due to the occurrence violent deformations at a narrow places of the forming region, as a result of non-uniform distribution of hoop compressive stresses and radial tensile stresses, so expected a lot of problems which accompany the forming. The most important is the surplus metal that composed at cup corners, because of the non-homogeneous flow of metals during entry into the die, so appear ears at the upper edge of the cup. To reduce that defect as little as possible, simulation model has been built by program (ANSYS 15) of deep drawing, and modify the blank from circular shape to triangular shape with a gradient corner radii (20, 28, and 35)mm. It was placed at opposite place to the draw tool form.
The effect of the blank form on the required drawn force, distribution of thickness and strains that associated with the forming process were also studied. To make comparison between the experimental results and the results of simulation, it was manufacturing drawing tool with the same specifications of the simulation model. The practical and simulation results showed that the low radii corners of triangular blank lead to failure of deep drawing, especially at radii corners (20 and 28)mm. While the best shape of the cup by used blank with corner radius 35mm, that required less force of drawing, and better distribution of the metal thickness and the strains.

Using laser in modifying the surfaces of various materials is an important topic in the present time. The type of alloy used in this investigation was 6009Al alloy. Laser has been used as inhibitor to reduce the corrosion rate by using Q-switching Nd: YAG Laser (with changing energy of laser and fixing other parameters) under laser shock peening (LSP) technique for 6009 AA in hydrochloric acid with concentration of 1 M and the immersion time of 30 minutes at room temperature. The corrosion rate was calculated by using the polarization method. The corrosion rate decreased from (0.366 to 0.016) mm/yr before and after using LSP, respectively. Therefore, this study aims to reduce the corrosion rate that occurs in 6009 Al alloy.