Journal of Engineering

Fatigue cracking is the most common distress in road pavement. It is mainly due to the increase in the number of load repetition of vehicles, particularly those with high axle loads, and to the environmental conditions. In this study, four-point bending beam fatigue testing has been used for control and modified mixture under various micro strain levels of (250 μƐ, 400 μƐ, and 750 μƐ) and 5HZ. The main objective of the study is to provide a comparative evaluation of pavement resistance to the phenomenon of fatigue cracking between modified asphalt concrete and conventional asphalt concrete mixes (under the influence of three percentage of Silica fumes 1%, 2%, 3% by the weight of asphalt content), and (changing in the percentage of asphalt content) by (0.5% ±) from the optimum. The results show that when Silica fumes content was 1%, the fatigue life increases by 17%, and it increases by 46% when Silica fumes content increases to 2%, and that fatigue life increases to 34 % when Silica fumes content increases to 3% as compared with control mixture at (250 μƐ, 20°C and optimum asphalt content). From the results above, we can conclude the optimum Silica fumes content was 2%. When the asphalt content was 4.4%, the fatigue life has increased with the use of silica fumes by (50%), when asphalt content was 5.4%, the additives had led to increasing the fatigue life by (69%), as compared with the conventional asphalt concrete pavement.

This paper is devoted to investigate experimentally and theoretically the structural behavior of reinforced concrete hollow beams which have internal transverse ribs under effect of shear. The number of the internal ribs is the major variable adopted in this research, while, the other variables are kept constant for all tested specimens. The experimental part includes poured and test of four (200x300x1200mm) beam specimens, three of these specimens were hollow with different locations of internal ribs and one of them was solid. The experimental results indicated that the shear strength are increased (33%) to (60%) for beams containing internal ribs in comparison with reference beam. Also, the change of beam state from hollow section to solid section led to increase the capacity for about (100%). In order to study more thoroughly the performance of tested beams, a nonlinear analysis using ANSYS-11 finite element program is used. The analytical results indicated that the load-deflection response, ultimate loads, and crack pattern are in good agreement with the experimental results.

Asset management involves efficient planning of economic and technical performance characteristics of infrastructure systems. Managing a sewer network requires various types of activities so the network can be able to achieve a certain level of performance. During the lifetime of the network various components will start to deteriorate leading to bad performance and can damage the infrastructure. The main objective of this research is to develop deterioration models to provide an assessment tool for determining the serviceability of the sewer networks in Baghdad city the Zeppelin line was selected as a case study, as well as to give top management authorities the appropriate decision making. Different modeling techniques were used based on statistical methods such as discriminant, and artificial neural network (ANN) which were used to build the deterioration models. The results of the discriminant model gave correct classification of 68.9% for the condition class of this line. The main significant influencing variables that play an important role in sewer networks were: sewer age, planning, performance and maintenance which is known as the Management function. From ANN model the confusion matrix gave correct classification of 76.7% and MSE 0.128.This study providing a good source of information for future planning.

In wide range of chemical, petrochemical and energy processes, it is not possible to manage without slurry bubble column reactors. In this investigation, time average local gas holdup was recorded for three different height to diameter (H/D) ratios 3, 4 and 5 in 18" diameter slurry bubble column. Air-water-glass beads system was used with superficial velocity up to 0.24 m/s. the gas holdup was measured using 4-tips optical fiber probe technique. The results show that the axial gas holdup increases almost linearly with the superficial gas velocity in 0.08 m/s and levels off with a further increase of velocity. A comparison of the present data with those reported for other slurry bubble column having diameters larger than 18" and H/D higher than 5 indicated that there is little effect of diameter on gas holdup. Also, local section-average gas holdups increase with increasing superficial gas velocity, while the effect of solid loading are less significant than that of superficial gas velocity.

Solar energy usage in Iraq is facing many issues; one of those is the accumulation “of the dust on the surface of the solar module which” would highly lower its efficiency. The present work study the effect of dust accumulation” on installing fixed solar modules with different inclined angles 15o, 33o, 45o, 60o. Evaluation of the solar modules performance under different circumstance conditions such as rain, wind and humidity are considered in study of dust effect on solar module performance. The results show that the lowest output average efficiencies of solar modules occurs at 15o horizontally inclined angle are 7.4% , 6.7% , 8.0% , 8.1%, and 8.4% for the corresponding months; June, July, August, October, and September respectively while the highest average efficiencies are 8.9% , 9.1% , 9.4% , 9.6% , 9.6% for an inclined angle 60o for the same month. lose power output rate for angle 15o horizontally inclined solar modules are as following 32.6%, 32%,31.6%,34.9%,26.2% for months; June, July, August, October, and September respectively , while the results for the 60o horizontally inclined solar module are 26.9%, 17%, 24.2%, 28.1%, and 9.7% for the same five months. As a final result is that the 15o horizontally inclined solar panel is less efficient compared with the 60o horizontally inclined solar panel and the difference in the results in the months was mainly due to the weather changes (summer and winter). The solar modules efficiency and lose power rate values for the inclination angles 33o and 45o are ranged between the values of 15oand 60o inclination angles.

This work is concerned with the study of the effect of cement types, particularly OPC and SRPC, which are the main cement types manufactured in Iraq. In addition, study the effect of mineral admixtures, which are HRM and SF on the resistance of high performance concrete (HPC) to internal sulphate attack. The HRM is used at (10%) and SF is used at (8 and 10)% as a partial replacement by weight of cement for both types. The percentages of sulphate investigated are (1,2 and 3)% by adding natural gypsum as a partial replacement by weight of fine aggregate. The tests carried out in this work are: compressive strength, flexural strength, ultrasonic pulse velocity, and density at the age of 7, 28, 90 and 120 days.
The results indicated that the SRPC mixes showed lower reduction in the properties of concrete compared to OPC mixes at all ages of test. The greatest reduction in compressive strength was at the age of (90) days for OPC mixes and the age of (28) days for SRPC mixes. After that, the concrete showed the lower reduction for all percentages of sulphate in fine aggregate. The results also indicated that the performance of HRM showed better results than the SF, and the replacement of 10% SF exhibits better results than 8% SF for both types of cement.

The governmental projects are considers the prevailing in Iraq, as most of the projects implemented by the Government, the major role played by governmental projects in the provision of services to citizens and improve the economic situation in the country in general, in addition to the huge number of these projects implemented by the governmental organizations and the large failure rates of it , and because of the fact that these projects are stumbled before they reach the stage of failure, The aim of this research to identify the main factors for the stumble projects in addition to identifying the most influential factor on the causes and consequences of it , like (cost overruns , time overruns , delay and scope creep ) , the most influential factors have been identified through the questionnaire of thirty three (director manager, project manager and engineer) in the governmental organizations who has extensive experience in project implementation . The factors (political situation, the security and the deteriorating economic, financial efficiency is good for the employer, the contractor and low-budget experience, poor design and lack of efficient manpower and resources) of the most important factors that lead to stumble projects.

The removal of fluoride ions from aqueous solution onto algal biomass as biosorbent in batch and continuous fluidized bed systems was studied. Batch system was used to study the effects of process parameters such as, pH (2-3.5), influent fluoride ions concentration (10- 50 mg/l), algal biomass dose (0–1.5 g/ 200 ml solution), to determine the best operating conditions. These conditions were pH=2.5, influent fluoride ions concentration= 10 mg/l, and algal biomass dose=3.5 mg/l. While, in continuous fluidized bed system, different operating conditions were used; flow rate (0.667- 0.800 l/min), bed depth (8-15 cm) corresponded to bed weight of (80- 150 g). The results show that the breakthrough time increases with the increase of bed depth but decreases with the increase of flow rate. Thomas and Yoon-Nelson models were used to analyze the experimental data and there was a good matching between the theoretical and the experimental data for both models. Desorption studies indicate that NaOH solutions at different pH values (8-10) were used to recover the fluoride ions sorbed onto the algal biomass. It is noteworthy that the desorption efficiency at pH =10 remains close to 95 % of the initial value of sorption capacity. So the desorption performance remains appreciable.

In this research, deposition of titanium oxide (TiO2) and vanadium oxide (V2O5) thin film in
different mixing percentage (0, 25 ,50, 75 and100)% on the substrate of glass .The coating
thickness was ( 50 nm ).
In this research contact angle was measured and the effect of weather conditions. Results showed
that the value of the contact angle of the prepared films reached its highest value at 50%
(TiO2+V2O5) was 160º.
The results showed that the optical transmittance of TiO2 and V2O5 thin film decrease with
increasing the deposition angle and decrease with increasing V2O5 proportion.

In this study, a three dimensional finite element analysis was utilized to study the behavior of reinforced concrete T-girders with and without web openings under pure torsion by using ANSYS APDL 15.0 program. Fourteen reinforce concrete T- girders were analyzed; one of the girders (without web openings) was modeled as a control girder. The analysis variables considered for the other girders are: size, shape, position of web openings, number of web openings and the method was used to strengthen the member at openings, (using internal deformed steel bars as in the case where the openings are planned before casting the girders). To study the general behavior of finite element models, torque-angle of twist plots at the end of the span near the loaded arms were represented. From this relation, it was showed a decreasing in the strength of the T-girders with web openings under the torsional loads and increasing of the angle of twist. The results were analyzed in terms of torque twist characteristics; ultimate torque, crack patterns, crack width, warping and stresses. These terms were presented and a comparison between the finite element results was made.