Al-Qadisiyah Journal for Engineering Sciences

he polyester matrix composites reinforced with short glass fiber and reinforced with glass fiber and Al2O3 particles with different weight fractions (3, 5, and 7 wt% Al2O3) were prepared and then the mechanical testing (bending, impact, and hardness) were measured. The results showed the mechanical properties improve with increasing weight fraction. The impact energy of hybrid composite is better than compared with the composite reinforced with glass fiber alone at same weight fractions.

The aims of this study is to investigation the effect of reinforcing with hybrid fibers included natural palms fibers and carbon fibers on thermal behavior of araldite resin(AY103) . This resin was reinforced with natural palms fibers is studied and compared it with another material reinforced by carbon fibers(°0)with (1.75g/cm3) density ,and then these two types of fibers combined together in same matrix to make a hybrid composite material and also calculated the range of it's thermal conductivity coefficient .Fourier equation used to calculate the thermal conductivity coefficient(k) to obtained composite material and. the results obtained from thermal conductivity test show that the thermal conducting value of natural palms fibers higher than reinforcing with carbon and hybrid fibers .

The objective of this research is to study the effect of reinforcement by carbon fibers as woven roving (°90-°0) with density (1.75gcm3)on thermal conductivity for unsaturated polyester resin after reinforcing it by different percentage of fibers (20%, 40%,60%) and we used Fourier equation to calculate the thermal conductivity coefficient (k) . Also the mechanical properties of this resin was calculated with the same reinforcing percentage of fibers and these properties included : impact strength , tensile strength , compression strength , flexural strength , and hardness . The results show that improvement in thermal and mechanical properties after reinforced by fibers , and these properties will rise as increased in reinforcement percentage .

Reinforced concrete beams for high-strength concrete often exhibit structural and nonstructural cracking due to variety steel reinforcement. Four reinforced concrete beams with dimensions of (120*230*2550)mm were investigated. Beams (1&2) have tensile steel ratio (0.0099), while beams (3&4) have tensile steel ratio (0.018). Deflections were measured at first third, second third and mid span for original repaired beams using dial gauges with accuracy 0.01 mm. The repair strength achieved for risen epoxy injection high-strength reinforced concrete beams was shown similar that original beams, but a little deference. The failure load for repaired beams higher than original beams.

Recent years have witnessed a rapid development in the understanding of heat exchangers design. Those developments have justified the use of a global minimum allowable temperature approach under which the heat transfer area of the heat exchanger is minimized. Values of the allowable pressure drops of streams of exchangers are specified to calculate film heat-transfer coefficients of streams and heat-transfer area. By coupling this with the understanding of what dictates the energy consumption, it is possible to determine the trade-off between the heat exchanger capital cost and energy cost prior to design work. Pressure drop is an important issue in the design of a heat exchanger. Pumps and (or) compressors must be installed to overcome pressure losses when streams flow through heat exchangers. The total cost for a system of pumps and compressors consists of the purchase cost of equipments and the electricity cost to run these equipments. This cost could occupy a significant part of the overall cost for a heat exchanger. Therefore, the pressure drop aspect should be considered together with the costs of heat exchanger area.
This paper demonstrates how pressure drop is considered in the context of a sludge double-pipe heat exchanger design. A relationship between heat transfer coefficient and heat exchanger pressure drop was determined and its capital cost implications were assessed.

Active control of the die-level temperature is desirable during production testing of high power microprocessors, so as to ensure accurate performance classification. The analysis in this research demonstrates fundamentals limits of temperature control for typical devices under test conditions. These limits are identified for specified control power to die power ratios. The effects of test sequence deign and device package design on the temperature control limits are also examined. The theory developed can be applied to any thermal control problem where a conductive medium separates the control source from the location where control is desired. As a dimensional example, when the die power density (Qd =10 W/cm2 ) and frequency of the die power variation ( =10 HZ) with ( = 4K ) , the required control power density ( Qc =63 W/cm2 ) . This performance is much better than for ideal temperature control where the control magnitude was found to be (173 W/cm2 ) with no change with the convective heat transfer coefficient f t when it varies from 500 W/m2.K to 2000 W/m2.K.

In this paper the finite element analysis of the cold flat rolling is well presented to predict the roll force, slab velocity at entry and exit, temperature rise in the slab during cold rolling, strain and stress distribution around the slab. The effects of friction coefficient and yield stress of slab material on rolling are assumed. It is found that maximum force occurs at the position of neutral point between entry and exit, also it is found that the velocity of slab at exit is larger than that at entry. The finite element results of temperature distribution around the slab predict that there is a considerable rise in slab temperature.

This investigation presents an experimental study of strength and behaviour of various types of reinforcement details in concrete corner subjected to bending moment tended to open the angle. Ten specimens with various arrangements of reinforcement in the corner region are tested to study the effect of reinforcement detail, corner strength, cracks type, cracking moment, cracks pattern, corner deflection and corner efficiency. The specimens are designed to represent an actual prototype of a portal frame corner. The compressive strength of concrete in the test varies from (37.1) to (43.6) MPa, and steel tension ratio in legs is constant at ρ = 0.0081 in all test specimens. The nominal dimensions of the tested corners are (1077.8 mm) in overall length, (600 mm) in height and (150mm) in thickness, the nominal width, and the effective depth for all corner's leg section is held constant at (150 mm) and (129 mm) respectively. All corners are supported to be hinged in one leg by two hooks and rolled in other leg, also all corners are loaded by steel frame where, it produces moment tends to open the angle. Concrete strains at three different loading stages are recorded for each tested corner; also load deflection curves were plotted. Throughout the test operation crack patterns were drawn and the mode of failure of the tested corners is identified, which is divided into two types (flexural and bearing) failure. It was found that reinforcement detailing in corners subjected to moment tends to open the corner has important effect on the strength and the mode of failure of the corner. Depending on the results of the current experimental work some details are recommended to be used in the field work.

The California bearing ratio (CBR) test has been widely used in pavement design since mid 1940's. It is a relative measure of sub-grade soil or base/sub-base aggregate strength. Nine samples, about 50 kg are taken from different test pits dig to 1.5m from natural ground surface, the soil is fine grained either silt or clay. The nine (CBR) specimens were compacted at optimum moisture content and at 95% of the maximum dry density of the modified compaction test were prepared.
All specimens were soaked for periods of 96hr with more than 4.5kg surcharge load. Penetration test was done for both two faces (top and bottom) of the specimen. The tests denoted that most CBR curves are convex upwards so no correction is needed. CBR number is less than 20 so is very poor to fair, where the best using for sub grade due to its fine grained soil. Mostly CBR number that is calculated from bottom face is grater than top face, as they are less wetting than top face.
The paper reveals that most CBR values are small, depended from 5mm penetration of the bottom face of specimens, which no correction method is needed for curves.

Mineral aggregates make up 90 to 95% of a HMA mix by weight or approximately 75 to 85% by volume. The properties of the mineral aggregates have significant affects in performance of our local roadways which offers the possibility of investment in these properties towards resisting different ranges of external applied loads and environmental conditions. For this reason, the performance properties susceptibility due to aggregate properties (Consensus and Source) is going to be evaluated with a wide range of blends, fine, medium and coarse gradation mixtures. The selected source property in this study was toughness (% abrasion), and the consensus property used in this study was angularity (% crushed). Results show that the medium graded mixtures were more susceptible in terms of Marshall Stability due to the change in % abrasion and % crushed aggregate, while the coarse graded mixtures were more susceptible in terms of Marshall Flow due to the change in % abrasion and % crushed aggregate.

Sanitary sewage treatment plants can be considered as a source for water that can be used
for different purposes. The agricultural sector is a steady and very big potential consumer of
reclaimed water . so , treated sewage reusing in agricultural purpose is a good goal where it requires
simpler treatment in comparison with other purposes
In this study , the quality of treated sewage in Najaf sewage treatment plant have been
evaluated and compared with standard specifications of America, Egypt and Iraq water quality that
used for agricultural purposes.
The evaluation process includes samples collection from effluent of treatment plant for a
period of (12) months from January 2009 to January 2010. Then measuring the quality of treated
sewage which includes measurement of Biochemical Oxygen Demand (BOD), Suspended Solid
(S.S) ,Total Dissolved Solid (TDS), and PH .Also concentration of chemical elements which may
cause harmful effect on plants like Cl,
Based on the results of this study it was found that: (1) Biochemical Oxygen Demand,
Suspended solid , Total Dissolved Solid and PH values of effluent treated sewage of all date of
measurement are within the maximum allowable range according to the Egyptian Standards and
American Standards. (2) the concentrations of values of chlorine (Cl),sulphate (SO4), Phosphate
(PO4), Sodium (Na) and Calcium(Ca) are :83%, 75%, 100%, 75%, 92% respectively are less than
the Egyptian allowable rang while 75% of magnesium (Mg) values are exceeding the allowable
limit. (3) TDS, PH, PO4, NO3 and Ca values of effluent treated sewage of all data of measurement
are within the Iraqi allowable range. (4) The concentration values of BOD, S.S, Na and Mg are
58%, 75%, 75% and 1% respectively are less than the Iraqi allowable range. (5) no sodicity
problem in the soil as a result of the use of treated water effluent from Najaf sewage treatment
plant.

The objective of this paper is to the estimate delay time at two important intersections in Baghdad City using Highway Capacity Manual Model (HCM) ,which is widely used for estimating delay at signalized intersections in Iraq, and Signalized and Unsignalized Intersection Design and Research Aid (SIDRA INTERSECTION 4) Model. Field traffic volumes and control delay were measured during peak and off-peak periods. Data on geometric design elements and signal timings and phasing were measured through a field survey. The results of the analysis indicated that SIDRA INTERSWCTION4 using HCM model was found to be the best in the comparison with the field values by observed percent of difference. Therefore a proposed model is build by derive a new parameters of the uniform delay term (d1) and random delay term (d2) for non-lane state. This model is validated on Art College Intersection. The results show that the predicted model cannot be used for other intersections. Then a proposed model is build for Art College Intersection.