Journal of Engineering

Two different composite materials were prepared by stir casting method of AA 6061 alloy as a matrix reinforced with two different ceramic materials Al2O3 and B4C of grain size 20 µm by 2.5, 5, 7.5, and 10% in weight. The composite material with aluminum alloy as a matrix possesses unique mechanical properties such as high specific strength and hardness, low density, and high resistance to corrosion and friction wear. This composite is widely used in automotive parts, space, and marine applications. Pin-on-disc technique was used to calculate the wear rate for each addition of Al2O3 and B4C particles. Rockwell hardness test and optical micrographs examinations were carried out to analyze, compare, and evaluate the addition of reinforced particles. The results of this investigation showed that the 7.5% of ceramic particles addition gave the highest values of hardness and wear resistance.

The distribution of chilled water flow rate in terminal unit is an important factor used to evaluate the performance of central air conditioning unit. A prototype of A/C unit has been made, which contains three terminal units with a complete set of accessories (3-way valve, 2-way valve, and sensors) to study the effect of the main parameters, such as total water flow rate and chilled water supply temperature with variable valve opening. In this work, 40 tests were carried out. These tests were in two groups, 20 test for 3-way valve case and 20 test for 2-way valve case. These tests were performed at three levels of valve opening, total water flow rate and water supply temperature according to the design matrices established by Design of Experiment (DOE) software 'version 7' with Response surface methodology (RSM) technique. The model was conducted for each case of total heat rate, then checked statistically for adequacy by Analysis of variance (ANOVA), and found good with 95% confidence level. The results showed that the water supply temperature has a significant effect on the total heat rate of two cases. It was found that the optimum solution for maximum total heat rate and minimum flow deviation represented by standard deviation was obtained at 10°C water supply temperature, 5.5 l/min total water flow rate and 70% valve opening. The total heat rate and standard deviation were (890.249 Watt), (0.000513), respectively in three-way valve case and (743.155 Watt), (0.00277), respectively in two-way valve case. Finally, the predicted and experimental results of total heat rate and standard deviation were in agreement with a maximum error of 6.6 % in three-way valve case and 1.4% in two-way valve case.

The current Iraqi standard specifications for roads and bridges allowed the prepared Job-Mix Formula for asphalt mixtures to witness some tolerances with regard to the following: coarse aggregate gradation by ± 6.0 %, fine aggregate gradation by ± 4.0 %, filler gradation by ± 2.0 %, asphalt cement content by ± 0.3 % and mixing temperature by ± 15°C. The objective of this work is to evaluate the behavior of asphalt mixtures prepared by different aggregates gradations (12.5 mm nominal maximum size) that fabricated by several asphalt contents (40-50 grade) and various mixing temperature. All the tolerances specified in the specifications are taken into account, furthermore, the zones beyond these tolerances are also observed. The evaluation process is illustrated by volumetric properties such as density, air voids, voids in mineral aggregate and voids filled with asphalt. Marshall test is carried out to find stability and flow values. The resistance to moisture effect is investigated by conducting the compressive test for dry and water immersed conditions to find the index of retained strength. The experimental results supported the recommendations to increase tolerances of coarse and fine aggregate gradations to ± 7.0 % and ± 5.0 % respectively. The optimum asphalt content tolerance can be increased to ± 0.5 %. The tolerances of filler gradation and mixing temperature are preferable to keep their current values.

HCl is separated from HCl–H₂SO₄ solution by membrane distillation process (MD). The flat-sheet membranes made from polyvinylidene fluoride (PVDF) and polypropylene (PP) were used in the process. The feed is a mixture of HCl and H₂SO₄ acids, with compositions depending on the metals treated. HCl concentration increased in the permeate during the process, while sulfuric acid increased gradually in the feed. During the concentration of solution acids, the initial concentrations in the feed were 50 g/dm³ of sulfuric acid and 50 g/dm³ of hydrochloric acid at 333K feed temperature, resulting in a permeate flux of 71 dm³/m²·d. At higher concentrations of HCl in the feed (111 g/dm³) and sulfuric acid (61 g/dm³) at the same feed temperature, the volume permeate flux was 57 dm³/m²·d. At higher concentrations of sulfuric acid in the feed (161 g/dm³) and HCl (60 g/dm³), the permeate flux decreased from 71 to 35 dm³/m²·d at 333K. Increasing the temperature to 343K caused an increase in permeate flux from 35 to 85 dm³/m²·d. The HCl concentration achieved a higher value of 9.1 g/dm³ during the process at a feed concentration of 161 g/dm³ of sulfuric acid and 60 g/dm³ of hydrochloric acid at a feed temperature of 343K.

Tigris River water that comes from Turkey represents the main water resource of this river in Iraq. The expansion in water river implementations has formed a source of trouble for the workers in the water resources management field in Iraq. Unfortunately, there is no agreement between Iraq and Turkey till now to share the water of this international river. Consequently, the optimal operation of water resources systems, particularly a multi-objective, multi-reservoir, is of the most necessity at the present time. In this research, two approaches were used: the dynamic programming (DP) approach and a simulation model to find the optimal monthly operation of Ilisu Dam (from an Iraqi point of view) through a computer program (in Q. Basic language) to find the optimum monthly release and storage by adopting an objective function that minimizes the release and storage losses (penalty). The historical inflow data of 588 months from (Oct. 1961 to Sep. 2009) formed the input data to the optimization models. Storage rule curves for the reservoir at (lower, mean, upper) of (10%, 50%, and 90%), respectively, were found according to the results of the optimized operation. A simulation model was developed to operate the system using these rule curves.

The problem of water scarcity is becoming common in many parts of the world. To overcome part of this problem, proper management of water and an efficient irrigation system are needed. Irrigation with a buried vertical ceramic pipe is known as a very effective method in the management of irrigation water. The two-dimensional transient flow of water from a buried vertical ceramic pipe through homogenous porous media is simulated numerically using the HYDRUS/2D software. Different values of pipe lengths and hydraulic conductivity were selected. In addition, different values of initial volumetric soil water content were assumed in this simulation as initial conditions. Different values of the applied head were assumed in this simulation as boundary conditions. The results of this research showed that greater spreading occurs in the horizontal direction. Increasing applied heads, initial soil water contents, and pipe hydraulic conductivities cause an increase in the size of wetting patterns, but only to a small extent. Also, the results showed that the empirical formulas which can be used for expressing the wetted width and depth in terms of applied head, initial soil water content, application time, pipe hydraulic conductivity, and pipe length, are good and can be used as design equations.

At present, smooth movement on the roads is a matter which is needed for each user. Many roads, especially in urban areas, are geometrically improved because of the increasing number of vehicles. In this research, Highway Capacity Software (HCS) 2000 was adopted to determine the effectiveness of the roundabout in terms of capacity, delay, and level of service. The results of the analysis indicated that the Ahmed Urabi roundabout operates under level of service F with an average control delay of 300 seconds per vehicle during peak hours. The through movements of Alkarrada-Aljadiriya direction (Major Direction) represent the heaviest traffic volumes in Ahmed Urabi intersection. The use of an underpass to serve the through movements in Alkarrada-Aljadiriya direction will lead to a 51% reduction in traffic volume at the Ahmed Urabi intersection. After adopting the proposed geometric design, it will operate at LOS B in the design year (2037). The proposed circulatory roadway width for the roundabout is 16m, and the required number of lanes is three for each side of the underpass and four for all the approaches of the roundabout.

The problem of rapid population growth is one of the main problems affecting countries of the world due to the growth in various environmental areas of life such as commercial, industrial, social, food, and educational sectors. This study was conducted on the amount of potable water consumed using two models of satellite and aerial images of the Kadhimiya District-block 427 and Al-Shu'laa district-block 450 in Baghdad city for the available years in the Secretariat of Baghdad (2005, 2011, 2013, 2015). Through the characteristics of geographic information systems, the spatial patterns of urban creep were revealed by determining the role and buildings to be created, which appear in the images for the years 2008, 2013, and 2015, respectively, compared to buildings and residential areas allocated in 2005. The comparison of each year before to estimate the number of the population is the bidder in these years. The amount of water consumed in this period has also been obtained to estimate the amount of water produced for sanitation. The knowledge of growing buildings, increasing population, and the percentage of increase in the amount of water consumed. Geographic information systems reveal spatial patterns of civilian creep by measuring dimensions in new urban expansion areas from the city center and roads. In various years, in order to understand changes that have occurred, particularly in the built-up areas, and to analyze urban congestion for periods of lagging and the growth prediction of urban areas in the coming years.

The research focuses on determining the best location of a high elevated tank using the required head of the pump as a measure for this purpose. Five types of networks were used to find the effect of the variation in the discharge and the node elevation on the best location. The most weakness point was determined for each network. Preliminary tank locations were chosen for testing along the primary pipe with the same interval distance. For each location, the water elevation in the tank and pump head was calculated at each hour depending on the pump head required to achieve the minimum pressure at the most weakness point. Then, the sum of pump heads through the day was determined. The results proved that there is a most economical location where the energy consumption is minimum. This location joined with the branched line that contained the most weakness point. The best location didn’t join with the highest demand location unless this location contained the most weakness point. The results indicated that moving the tank away from the best location in the pump direction results in pump head increasing that exceeds the increase in pump head when the tank moves in the opposite direction. The location of the tank beside the pump station was the worst location. Also, the results showed that as the distance between the pump and the highest demand becomes shorter, the required pump head becomes less. The uniform demand distribution required the least amount of pump head, it required a minimum head of 554m while the networks, that have the highest demand at distances of 200m, 400m, and 1000m from the pump station, required a minimum head of 651m, 682m, and 726m respectively.