Journal of Engineering

The research hypothesis depends on the existence of a general phenomenon in the contracts business of the contractors represented in the fact that the actual costs of the contracts expended during the execution period exceed the estimated costs of the constructive contracts in the tender presentation phase , resulting in a financial shortage and economic problems for the contractors. The research has adopted the lifecycle of system building which goes through different phases: the problem identification, the problem analysis and the design of the proposed management system. To achieve this goal, both the standard local and international systems have been studied.Morover, the proposed management system has been programmed in accordance with the various computer programmes so that all of them form a developed computer program used for pricing the various activities of the construction contracts.A faster and more accurate program that is also characterized by being simple, scientific,efficient and easily used by the contactors. It is also flexible enough for being developed and adjusted to future changes. Furthermore, it depends on work breakdown structure and agrees with the united standard guide of quantity survey for civil engineering works.

By using governing differential equation and the Rayleigh-Ritz method of minimizing the total potential energy of a thermoelastic structural systemof isotropic thermoelastic thin plates,thermal buckling equations were established for rectangular plate with different fixing edge conditions and with different aspect ratio. The strain energy stored in a plate element due to bending, mid-plane thermal force and thermal bending was obtained.Three types of thermal distribution havebeen considered these are:uniform temperature,linear distribution andnon-linear thermaldistribution across thickness.It is observed that thebuckling strength enhanced considerably by additional clamping of edges.Also,thethermal buckling temperatures and thermal buckling load have lowest values at first mode of buckling for all types of ends condition and with all values of aspect ratios.

The aim of this research work is to study the effect of stabilizing gypseous soil, which covers vast areas in the middle, west and south parts of Iraq, using liquid asphalt on its strength properties to be used as a base course layer replacing the traditional materials of coarse aggregate and broken stones which are scarce at economical prices and hauling distances. Gypseous soil brought from Al-Ramadi City, west of Iraq, with gypsum content of 66.65%, medium curing cutback asphalt (MC-30), and hydrated lime are used in this study. The conducted tests on untreated and treated gypseous soil with different percentages of medium curing cutback asphalt (MC-30), water, and lime were: unconfined compression strength, and one dimensional confined compression under both dry and absorbed test conditions. The test results showed that stabilizing gypseous soil using the optimum fluid content of 16% (5% cutback asphalt+11% water) have improved the unconfined compressive strength, compressibility, rebound consolidation, and waterproofing of gypseous soil, but under absorbed condition the stabilized gypseous soil using cutback asphalt only did not satisfy the requirements for base course construction, therefore it was decided to use lime additive to improve the properties of soil-cutback mixture under absorbed condition.

Experimental research was carried out on eight reinforced concrete beams to study the embedded length of the longitudinal reinforcement. Six beams were casted using self compacted concrete, and the two other beams were casted using normal concrete. The test was carried out on beams subjected to two point loads. The strain and the slip of the main reinforcement have been measured by using grooves placed during casting the beams at certain places. The measured strain used to calculate the longitudinal stresses (bond stress) surrounding the bar reinforcement, The study was investigated the using of self compacted concrete SCC on the embedded length of reinforcing bars, and comparing the results with normal concrete. The test results show that using SCC improve the concrete properties like the compressive strength and the tensile strength which mainly affected the bond strength and the splitting of the concrete cover failure. The testes show that with increasing concrete strength the bond strength increased.

One of these properties is stiffness (resilient modulus). To explain the effect of air temperatures on stiffness of asphalt concrete, it is necessary to determine the distribution of temperatures through the pavement asphalt concrete layers. In this study, the distribution of pavement temperatures at three depths (2cm, 7cm, 10cm) below the pavement surface is determined by using the temperature data logger instrument.

A relationship for determining pavement temperature as related to depth and air temperature has been suggested.

To achieve the objective of this thesis, the prepared specimens have been tested for indirect tension in accordance with ASTM D4123, using the pneumatic repeated load apparatus, in order to determine the values of resilient modulus at three different temperatures (10, 25, 40)°C.

From results of testing, it is observed that the resilient modulus decreases with increase in test temperature by a rate of 8.78×10³ Psi/°C for asphalt concrete wearing courses.

An increase in optimum asphalt content by 0.1% (by weight of total mixture) causes a decrease in resilient modulus by 22% at a temperature of 40°C.

A statistical model for the prediction of resilient modulus has been developed depending on mixture variables of: asphalt content, asphalt binder viscosity, surface area of combined aggregates, air voids of compacted mixture and test temperature.

Flow of water under concrete dams generates uplift pressure under the dam, which may cause the dam to function improperly, in addition to the exit gradient that may cause piping if exceeded a safe value. Cutoff walls usually used to minimize the effect of flow under dams. It is required to 1)minimize the flow quantity to conserve water in the reservoir, it is also required to 2)minimize the uplift pressure under the dam to maintain stability of the dam, and it is required to 3) minimize the exit gradient to prevent quick condition to occur at the toe of the dam where piping may occur and may cause erosion of the soil. Varying the angle of cutoff walls affects its influence on the factors aforementioned that are required to be minimized. In this paper, the cutoff wall angle was varied from 0° to 180° using GeoStudio 2007 SEEP/W computer program, and the variations of the three factors were studied and analyzed. The results shows that the best angle to minimize the water flow is about 60°, the best angle to minimize the uplift pressure was about 120° to 135°, and the best angle to minimize the exit gradient was about 45° to 75°. The case where two cutoff walls were used one with angle 60°, the other with an angle 120°were investigated. The results indicated where the minimum values for all factors may be obtained.

In the present study, a low cost adsorbent is developed from the naturally available sawdust which is biodegradable. The removal capacity of chromium(VI) from the synthetically prepared industrial effluent of electroplating and tannery industrial is obtained. Two modes of operation are used, batch mode and fixed bed mode. In batch experiment the effect of Sawdust dose (4- 24g/L) with constant initial chromium(VI) concentration of 50 mg/L and constant particle size less than1.8 mm were studied. Batch kinetics experiments showed that the adsorption rate of chromium(VI) ion by Sawdust was rapid and reached equilibrium within 120 min. The three models (Freundlich, Langmuir and Freundlich-Langmuir) were fitted to experimental data and the goodness of their fit for adsorption was compared. In the fixed bed isothermal adsorption column, the effect of particle size (dp) (1.09-1.8) mm, influent flow rate (Q) (1- 4) L/hr, bed depth (H) (25- 35) cm and the pH(1-7)of the solution were studied .The results show that Sawdust is an efficient adsorbent for the removal of Cr(VI) from wastewater. Percent removal of chromium reaches (100%) with increasing of contact time and decreasing the pH.UV- Spectrophotometer was used to determine the metal ion concentration.

Mechanical degradation hampers the practical usage of polymers for turbulent drag reduction application. Mechanical degradation refers to the chemical process in which the activation energy of polymer chain scission is exceeded by mechanical action on the polymer chain, and bond rupture occurs.When a water-soluble polymer and surfactant are mixed in water solution, the specific structures (aggregates) are formed, in which polymer film is formed around micelle. In this work, Xanthan gum (XG) – Sodium lauryl ether sulfate (SELS) complex formation and its effect on percentage viscosity reduction (%VR) was studied. It was found that SELS surfactant reduced the mechanical degradation of XG much more efficiently than this polymer alone. Xanthan Gum (XG) has been tested for its shear stability and degradability. 0.5% and 1.0 % by weight concentration solutions were exposed to shear stirring at different speeds and time; also 0.5% through 1.5% by weight concentration solutions of SELS were added to XG solutions to determine the ability of SELS to reduce the mechanical degradation of XG. It has been noticed by measuring the percentage viscosity reduction (%VR) of the mixture of XG-SELS that the % VR decreases when added this surfactant to XG polymer

In this paper, a method is proposed to increase the compression ratio for the color images by dividing the image into non-overlapping blocks and applying different compression ratio for these blocks depending on the importance information of the block. In the region that contain important information the compression ratio is reduced to prevent loss of the information, while in the smoothness region which has not important information, high compression ratio is used .The proposed method shows better results when compared with classical methods(wavelet and DCT).

The Al Mishraq site has been the subject of many scientific studies for the period before and after the fire in 2003. Five visits to the site were conducted twice in 2003 for general fact-finding, twice in 2004, and once in 2005 for detailed sampling and monitoring. Desk-based research and laboratory analysis of soil and water samples results indicate that surface water and groundwater pollution from Al Mishraq site was significant at the time of its operation. The primary pollution source was the superheated water injection process, while the principal receptor is the River Tigris. Now that the plant is idle, this source is absent. Following the June 2003 sulphur fire, initial investigations indicate that short damage to vegetation was severe close to the plant but there is no evidence of widespread or significant long-term damage. Rainwater and drainage ponds and gullies close to the sulphur processing and acid contain hazardous levels of acid. Runoff from these areas may be affecting local water quality. There is regional moderate groundwater contamination by sulphate and hydrogen sulphide, but much of this may be naturally sourced. The site in its current state represents a low risk to human health and the environment principally due to the acidic surface water ponds, but in the absence of corrective action, the hazard levels may be elevated after some decades

The ground level ozone concentration at different locations in Baghdad city was identified. Five different sites have been chosen to identify the ground level ozone concentration. Al- Dora and Al-Za\'afarania were chosen as areas contained point source ( power plant station ) in addition to high traffic load , while Al –Uma park, Aden square and Al-Mawal square were chosen as area contained heavy traffic only (line source). The measurement focuses on spring and fall because these periods display favorable meteorology to ozone formation. During the research period the maximum values (peaks) for ground level ozone concentration were observed at fall: at Al-Za\'afarania area 101ppb as an average, at Al-Dora 87 ppb as an average and at line source areas 48 ppb as an average. Among the line sources area Al-Mawal square represent the highest peak value at fall 68 ppb. At spring the peaks of ozone concentration observed to be at the same height, 50 ppb for all sites. The downwind sites from the power plant stations at Al-Dora and Al-Za\'afarania areas record higher ozone peaks compared with up wind sites. It can be concluded that the effect of power plant stations in forming ozone is larger than traffic load. The comparison between the ground level ozone concentrations that measured during the research period in spring and fall, and the ambient air quality standards (AAQS) shows that: •No exceeded levels were observed in spring for all sites. •In fall the AAQS for ozone was exceeded in Al-Za\'afarania area at 12: PM, 1: PM, 2: PM and 3: PM, and in Al-Dora at 2: PM.

The present work investigates the effect of magneto – hydrodynamic (MHD) laminar natural convection flow on a vertical cylinder in presence of heat generation and radiation. The governing equations which used are Continuity, Momentum and Energy equations. These equations are transformed to dimensionless equations using Vorticity-Stream Function method and the resulting nonlinear system of partial differential equations are then solved numerically using finite difference approximation. A thermal boundary condition of a constant wall temperature is considered. A computer program (Fortran 90) was built to calculate the rate of heat transfer in terms of local Nusselt number, total mean Nusselt number, velocity distribution as well as temperature distribution for a selection of parameters sets consisting of dimensionless heat generation parameter()0.20.0≤≤Q, conduction – radiation parameter()0.100.0≤≤N, and the dimensionless magneto hydrodynamic parameter()0.10.0≤≤M. Numerical solution have been considered for a fluid Prandtl number fixed at (Pr=0.7), Rayleigh number()521010≤≤lRa. The results are shown reasonable representation to the relation between Nusselt number and Rayleigh number with other parameters (M, N and Q). Generally, Nu increase with increasing Ra, M, N and Q separately. When the MHD, N, and Q effect added to the heat transfer mechanism, the heat transfer rate increased and this effect increased with increasing in Ra, MHD, N, and Q. The effect of magneto hydrodynamic, heat generation and heat radiation on the rate of heat transfer is concluded by correlation equations. The results are found to be in good agreement compared with the results of other researchers.

In this work an experimental study is performed to evaluate the thermal performance of locally made closed loop solar hot water system using a shell and helical coiled tube heat exchanger as a storage tank. Several measurements are taken include inlet and outlet temperatures of both collectors and supply water and temperature distribution within the storage tank. This is beside the water flow rate in both collectors and load cycle. The main parameters of the system are obtained.

A general velocity profile for a laminar flow over a flat plate with zero incidence is obtained by employing a new boundary condition to the other available boundary conditions. The general velocity profile is mathematically simple and nearest to the exact solution. Also other related values, boundary layer thickness, displacement thickness, momentum thickness and coefficient of friction are nearest to the exact solution compared with other corresponding values for other researchers.

This study deals with free convection heat transfer for the outer surface of two cylinders of the shape of (Triangular & Rectangular fined cylinders with 8-fins), putted into two different spaces; small one with dimension of (Length=1.2m, height=1m, width=0.9m) and large one with dimension of (Length=3.6m, height =3m, width=2.7m). The experimental work was conducted with air as a heat transport medium. These cylinders were fixed at different slope angles (0o, 30o, 60o and 90o) .The heat fluxes were (279, 1012, 1958, 3005, 4419) W/m2, where heat transferred by convection and radiation. In large space, the results show that the heat transfer from the triangular finned cylinder is maximum at a slope angle equals to 90o and is minimum at the slope of 0o angle whit the heat transferred from the triangular finned cylinder is maximum at slop angle of 30o and minimum at the slop of angle 60o in the small space with following range of the Raleigh number (1.68*107-3.46*108).

Friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force, etc., and tool pin profile play a major role in deciding the weld quality. In this investigation an attempt has been made to understand the effect of tool pin profile and rotation diameter on microstructure and mechanical properties in aluminum alloy (2218-T72). Five different tool pin profiles (straight cylindrical, threaded cylindrical, triangular, square, and threaded cylindrical with flat), with three different rotation diameter (3, 4, 5) mm. have been used to fabricate the joint. Effect of tool pin profile on mechanical properties of welded joints were investigated using different mechanical tests including (tensile, bending and microhardness tests). Microstructure characteristic during (FSW) process was studied and different welding joint were investigated using optical microscope. Based on the stir welding experiments conducted in this study the results show that aluminum alloy (2218-T72) can be welded using (FSW) process with maximum welding efficiency (86.95%) and (83.21%) in terms of ultimate tensile strength and bending force respectively using tool pin profile (threaded cylindrical with flat) with rotation diameter (5) mm, rotation speed (900rpm) and (30mm/min) welding speed.

A field experiment was conducted at experimental field of Mechanization Agriculture , the College of Agriculture , Abu – Ghraib , University of Baghdad .To measure transmitted vibration to seat tractor during operation tillage , mold board plow with New Holland 66-S- 80 tractor as one machinery unit , Soil was treated at soil constant moisture ( 18 – 20 % ) with two depths of plowing (15 and 20 cm ) and three speed of tractor 2.0 , 3.5, 6.8 km / h . Three main dimensions in seat tractor measurement vertical, longitudinal and lateral acceleration. Split plot design under completes block design with three replicates .

Agent technology has a widespread usage in most of computerized systems. In this paper agent technology has been applied to monitor wear test for an aluminium silicon alloy which is used in automotive parts and gears of light loads. In addition to wear test monitoring، porosity effect on wear resistance has been investigated. To get a controlled amount of porosity, the specimens have been made by powder metallurgy process with various pressures (100, 200 and 600) MPa. The aim of this investigation is a proactive step to avoid the failure occurrence by the porosity. A dry wear tests have been achieved by subjecting three reciprocated loads (1000, 1500 and 2000)g for three periods (10, 45 and 90)min. The weight difference after each test is immediately measured to find the losing weight and wear rate for each specimen. Wear test was monitored online by two sensors, force sensor to control the applied load, find friction force and coefficient of friction. The sensor is an acoustic emission to detect crack initiations of the worn surface by transfers the emitted ultrasonic waves from crack initiations to electric signals. Scanning electron microscope has been used to examine the worn surfaces. The overall results include that the effect of pores depends on pore shapes, sizes and concentrations.

Theoretical and experimental investigations have been carried out on developing laminar combined free and forced convection heat transfer in a vertical concentric annulus with uniformly heated outer cylinder (constant heat flux) and adiabatic inner cylinder for both aiding and opposing flows.The theoretical investigation involved a mathematical modeling and numerical solution for two dimensional, symmetric, simultaneously developing laminar air flows was achieved. The governing equations of motion (continuity, momentum and energy) are solved by using implicit finite difference method and the Gauss elimination technique. The theoretical work covers heat flux range from (200 to 1500) W/m2,Re range from 400 to 2000 and (1.36×105≤ Ra ≤ 1.1×107) with radius ratio of 0.555 which is the same radius ratio used in the experimental part of this study and Pr=0.7.The experimental work includes construct a rig consists essentially of an annulus with uniformly heated outer cylinder and adiabatic inner cylinder to give clear insight into heat transfer process and compare its results with that obtained in theoretical part, the range of the study are (Re= 383, 724, 1000, 1500) and heat flux equal to (q =370, 422, 588, 980) W/m2. Numerical results were represented by the temperature profile, axial velocity profile, outer surface temperature and the distribution of local Nusselt number along the dimensionless axial distance. The velocity and temperature profile results have revealed that the secondary flow created by natural convection have significant effects on the heat transfer process. Results reveal also that the experimental local Nusselt number along the annulus follows the same trend as present theoretical results with mean difference 10.23 %.

Particulate matter(PM) emitted from diesel engine exhaust have been measured in terms of mass, using 99.98 % pure ethanol blended directly, without additives, with conventional diesel fuel (gas – oil),to get 10 % , 15 %, 20 % ethanol emulsions . The resulting PM collected has been compared with those from straight diesel. The engine used is a stationary single cylinder, variable compression ratio Ricardo E6/US. This engine is fully instrumented and could run as a compression or spark ignition. Observations showed that particulate matter (PM) emissions decrease with increasing oxygenate content in the fuel, with some increase of fuel consumption, which is due to the lower heating value of ethanol. The reduction in PM formation increased with load increase, maximum reduction were 58% at 1800 rpm. There was no significant reduction observed at low loads. It could be concluded from the test results that ethanol may be an alternative to / or partially substitute, fossil fuels.

Experiments have been conducted to study the local and average heat transfer by mixed convection for hydrodynamically fully developed, thermally developing and fully developed laminar upward air flow in an inclined annulus with adiabatic inner cast iron tube and uniform heated outer aluminum tube with an aspect ratio (Ω= 0.72) and (L/Dh≈40) for both calming and test sections). A wide range of Reynolds number from 859 to 2024 has been covered, and heat flux has been varied from 159 W/m2 to 812 W/m2 (these values of heat flux and Reynolds number gave Richardson number range from 0.03 to 0.٣٨), with angles of annulus inclination φ=0o (horizontal position), φ=60o (inclined position), and φ=90o (vertical position). The hydrodynamically fully developed condition has been achieved by using aluminum annulus (calming section) has the same dimensions as test section and has connected with it by Teflon piece. The average Nusselt numbers have been correlated with the product of (Richardson number and Reynolds number) and compared with available literature and showed satisfactory agreement. The temperature and local Nusselt number profiles results have revealed that the secondary flows created by natural convection have a significant effect on the heat transfer process.

In this research the results of applying Artificial Neural Networks with modified activation function to perform the online and offline identification of four Degrees of Freedom (4-DOF) Selective Compliance Assembly Robot Arm (SCARA) manipulator robot will be described. The proposed model of identification strategy consists of a feed-forward neural network with a modified activation function that operates in parallel with the SCARA robot model. Feed-Forward Neural Networks (FFNN) which have been trained online and offline have been used, without requiring any previous knowledge about the system to be identified. The activation function that is used in the hidden layer in FFNN is a modified version of the wavelet function. This approach has been performed very successfully, with better results obtained with the FFNN with modified wavelet activation function (FFMW) when compared with classic FFNN with Sigmoid activation function (FFS) .One can notice from the simulation that the FFMW can be capable of identifying the 4-Links of SCARA robot more efficiently than the classic FFS.

The vortex rate sensor is a fluidic gyroscope with no moving parts and can be used in very difficult conditions like radiation, high temperature and noise with minimum cost of manufacturing and maintenance. A vortex rate sensor made of wood has been designed and manufactured to study theoretically and experimentally its static performance .A rig has been built to carry out the study, the test carried out with three different air flow rates (100, 150, and 200 l/min).The results show that the relation between the differential pressure taken from the sensor pickoff points and the angular velocity of the sensor was linear.The present work involved theoretical and experimental study of vortex rate sensor static characteristics .Vortex rate sensor has been designed and manufactured with dimensions :- Radius of vortex chamber= 140 mm, Radius of sink tube rs= 4.5 mm, the pickoff hole diameter = 2mm, Height of vortex chamber b= 19 mm, Height of pickoff pipe h= 25 mm.

In this researchthe relation between skin resistances and standard penetration test of over consolidated clay soils has been studied. The research includes doing boreholes at Babil governorate in Iraq to get undisturbed samples and standard penetration test. Determination skin friction from direct shear test between smooth concrete and soil was explored in laboratory for design purposes and correlated with standard penetration test values. In many foundation design problems, the shear strength between soil and foundation materials were estimated or correlated without any direct methods for measurement. Twelve strain controlled direct shear tests were performed simulate the shear strength interaction between smooth concrete and undisturbed over consolidated silty clay, determine the soil – foundation interface friction, considering the following variables :(1) over consolidation ratio OCR between 1.4 to 2.4 (2) Concrete, smooth surface, (3) Undisturbed samples, (4) Variation of the normal load between the friction surface. The results showed that both cohesion and internal friction should be considered in evaluating skin friction. The results of cohesion and angle of internal friction were correlate with the standard penetration test SPT –N . Interface friction angle was 14.5° , while the adhesion was 15.5 kPa. The ultimate shear strength was mobilized through 10%- 16% strain in the direction of shear surface. . A fairly good correlation between the N70-value and the interface friction parameters were established for determination unit skin friction for driven piles.Finally, based on the test results, a simple relation was proposed to relate the N70 value and interface friction of silty clay soils for a range of N70 between 12 and 20.

Used vegetable oil was introduced to transesterfication reaction to produce Biodiesel fuel suitable for diesel engines. Method of production was consisted of filtration, transesterfication, separation and washing. Transesterfication was studied extensively with different operating conditions, temperature range (35-80oC), catalyst concentration (0.5-2 wt. % based on oil), mixing time (30-120 min.) with constant oil/methanol weight ratio 5:1 and mixing speed 1300 rpm. The concentration of Fatty acid methyl esters (Biodiesel) was determined for the transesterficated oil samples, besides of some important physical properties such as specific gravity, viscosity, pour point and flash point. The behavior of methyl esters production and the physical properties of Biodiesel were studied with the different operating conditions. The results show that increasing methyl esters concentration with increasing temperature and catalyst concentration and the transesterfication is a second order reaction The research aiming to recycle spent cooking oils to prevent pollution of soil and water, and converting them to Biodiesel fuel with low emissions.