Journal of Techniques

The paper is adopted to evaluate the microstructure of normalized steels and determine the relationship between the volume fraction of cementite and hardness for the different structures. The other part of the study is to determine the adhesive wear rate and the wear mechanism(s).
It was found that the subsurface deformation increased with decreasing the carbon content, implying that the bearing pressure is a constant. Deep groves formed when the carbon content is low for the normalized steels. The results confirm that the main mechanism of adhesive wear is the surface fatigue from the interaction of micro and macro cracks started from the subsurface region

This research is an experimental study of a storage solar collector. The design is simple and low cost compared with other solar water heaters. Giving a capacity of about (140 liter). An experimental study includes testing the storage solar collector under different operating conditions of Baghdad City during the test period from February 2005 to July 2005. The experimental results show it is possible use to a storage solar collector for domestic hot water applications.
Where possible heating (140 liter ) of water to different temperatures depends on stratification phenomenon. It is noted that maximum temperature for ( 7 February ) is ( 51.5 ْC ) and minimum temperature is ( 29 ْC ) , while the average temp. is ( 37 ْC ) when is initial temperature of water equals (16.3). ْC ) , This means rise water temperature of ( 21 ْC ).

The current numerical study is conducted to analyze mixed convection heat transfer in lid- driven cavity with a sinusoidal wavy bottom surface. The cavity vertical walls are insulated while the wavy bottom surface is maintained at a uniform temperature higher than the top lid. The governing equation was wrote in terms of stream- vorticity, then it was changed from the differential form to the algebraic by using finite difference method, also body fitted coordinate system was used to change the equation from the cartizian coordinate to the general coordinate. The validity of the numerical code used is ascertained by comparing the results with previously published results. The implications of Richardson number, number of wavy surface undulation and amplitude of the wavy surface on the flow structure and heat transfer characteristics are investigated in detail while the Prandtl number is considered equal to (Pr = 0.71).the results shows that the average Nusselt number increase with an increase in both the amplitude of the wavy surface and Reynolds number. Maximum heat transfer occurs when the wavy surface is designed with two undulations while subjected to low Richardson number

In this paper , two types of material are used , the first is medium carbon steel and the latter is high speed steel . These materials welded by friction welding for two samples ( Similar And Dissimilar ) . The optimum conditions for welding had been select by single factor method .Which represent that the optimum conditions for similar materials are : (12 sec ) for friction time, (2.2MPa ) for forging pressure and (0.8 MPa ) for friction pressure , So, for dissimilar materials that are : (16 sec ) for friction time , ( 2.7 MPa ) for forging pressure and (1.4 MPa ) for friction pressure . The experimental results indicated that the tensile strength of the welded joint of similar material was about of (92%) from the base metal strength while in dissimilar case , it was ( 70%) .

This paper is aimed to study the effect of ball size employed in shot-peening operation on the fatigue strength of low carbon alloy steel. (4135-AISI) also show the comparison of fatigue strength to the same metal between specimen treated by surface hardening nitriding operation. The results indicate that the fatigue strength improving when the ball size used in the shote-peening increased also the fatigue strength increased in the specimen shot peened after nitriding operation by steel balls with diameter 1.25 mm. all fatigue test done by rotating bening at mean stress=0 .

The aim of this research was to study the effect of polymeric additives to water on friction factor change in a turbulent pipe flow.
Experiment was done using the polyacrylamide ( PAM ) as polymeric additive to show the effect of addition of ( PAM ) with low concentrations (0.005,0.013 , 0.025%) on the friction factor (λ) . The results showed that the addition of (PAM) will reduced (λ) with a range of 6.51 to 37.95% comparable with the friction factor (λ) for water befor addition in a turbulent flow . Also studied the effect of addition ( PAM ) with high concentrations between( 0.03 – 0.06% ) on the reduction percent of (λ) .
The results showed increasing the effect of the addition ( PAM ) on the reduction percent of (λ) with arrange of 21.32 to 44.62% and decreasing the effect of addition ( PAM ) on (λ) when exceeded the optimum values of PAM concentrations (0.03-0.042%) at several Reynold's numbers . A relations have been obtained between Reynold's numbers and (λ) and between the concentrations ( C%) with reduction percent of (λ) .

The production of duplex composite materials by high power vcontinuous CO2 laser were produced from mixture of 316L stainless steel and yttria partially stabilized zirconia (YPSZ). It was found that the clad layers are consisted of dendrite structure of austenitice phase surrounding by delta ferrite and distinct regions of yttria partially stabilized zirconia. The YPSZ has been distributed randomly in clad regions with lower volume fraction of the ceramic powder before cladding. The presence of delta ferrite in the austenitte phase as well as the high ccoling rate lead to increase the hardness to the double . of austenite phase alone and in the range of 400 to 500 Hv. The presence of ceramic material with special phase transformation leads to produce new material with high performance and new process to produce special composite materials

This study deals with the specifications of waste water that comes from the Modern Paint Company which includes industrial waste water coming out of the emulsion paint department and sewage thrown into the Tigris river and how much is it agreement with the Iraqi specifications of rivers protection system.
PH , BOD , TDS , TSS , SO4-2 , PO4-3 , NO3-1 , Cl-1
Tests were made to waste water in the period from January to June 2001. Results showed that the specifications of water coming from the treatment unit have been within the limits except the biological need for Oxygen for some samples because of damage in the airation pumps.

The main object of the present work is to study the effect of internal sulphate( ) which is present in the concrete raw materials .Natural calcium sulphate hydrate (Gypsum( )) was used as a source of internal sulphate ( ). In order to study the effect of various percentages of culcium sulphate ( ) on the properties of the hard concrete , specimens were prepared for compressive strength test , in the formed of (100mm) concrete cubes with selective mix proportionas of 1:2:4(1 cement : 2Sand : 4 gravel) by weight and water/cement ratio of 0.5 Also high percentage of calcium sulphate was added to the concrete mixes.Results have shown that the compressive strength of concrete at 28 days after curing , decreases by 50.9% , 65.5% , 66.73% when added calcium sulphateis in 3% , 5% , 7% by weight of sand to concrete mixes , respectively .
Also results have shown that when increasing the percentage of cement content by 3% , 9% , 11% in concrete mixes ,which contain calcium sulphates in 3% , 5% , 7% by weight of sand ,the compressive strength of concrete at 28 and 60 days does not decrease and has the same compressive strength of concrete without sulphates

Finned-tube heat exchangers are widely used in space conditioning systems, as well as any other applications requiring heat exchange between liquids and gases. The only significant opportunity for electrical power use reduction residential in air conditioners is in technology improvement of the finned-tube heat exchangers
In this investigation, two operating parameters that a effect the air cooled condenser, air velocity and ambient temperature are studied. The velocity of air flow over the condenser ranges between 0.5 m/s and 3 m/s and the ambient temperatures are (20,28,and35)°C. It is found that condensers employing tubes of smaller diameters yield the best system performance. The effect of pressure drop for refrigerant side and air side on performance unit has been studied also.
It is concluded that when the air velocity riss the condensing temperature is reduced and the work of compressor is reduca in the cycle, then the refrigerating effect rises and the coefficient of performance increases also. And when the ambient temperature rises the condensing temperature rises too and the refrigerating effect is reduce as result of the coefficient of performance decrease. Also when the air velocity over condenser rises the number of heat transfer units rises too therefore the effectiveness of condenser rises

This papar aims, mainly, to introduce the new concept of‘‘ RYAD and ellustrating its mathematical structure . Many new concepts are Introduced like the concepts of ’’ effect’’ ؛ ’’ effect matrix ’’ ؛ ’’ effect diagram ’’؛’’effect coordinates system ’’؛’’ RYADIC transformation of coordination’’؛’’RYADIC equation ’’؛’’RYADIC matrix multiplication؛’’ … etc.

With the absence of reliable accident record, traffic conflict technique is a suitable alternative aid to conduct a study of traffic safety. This research aims to conduct such study at four leg- signalized intersections using traffic conflict technique.

Surveys include traffic conflict, volume data, spot speed and some geometric characteristics at four sites in Baghdad city. Rate quality control and cluster analysis are used to identify the hazardous approach and the abnormal conflict types respectively.
Developed models show that, linear relationships are significantly appropriate to explain the relation between hourly traffic conflict and hourly approach traffic volume with coefficient of determination ranging between 0.701 and 0.884. Although this finding agrees with the literatures, exponential relationship introduces higher coefficient of determination between 0.759 and 0.897. This might be due to extra increase in conflicts at high traffic volume. Further, a model of multiple linear is appropriate to explain the relation between conflict rates and some of geometric characteristics with coefficient of determination ranging between 0.580 to 0.969. Identification of hazardous approach shows that, the lower rank in geometric characteristics among all approaches is the most hazardous one. This agrees with the finding in the developed model. In order to enhance traffic safety, the study proposes suitable countermeasures such as creating left turn lane, providing special phase for left-turn traffic.
المستخلص

Oil and its products as one of active sources of energy due to their operating and economic properties, there is a shortage of information about the behavior of concrete under oil effect, most of the recent researches tend to study the possibility of using reinforced concrete has oil products storage as an alternative to the expensive steel storage. This research studied the effect of two products, crude oil and kerosene of concrete and its possibility of reducing this effect by using (1%) of fibers reinforced of total mix volume, (5.5%) by cement weight of superplasticizer type (Melment L10) and (30%) of slag by weight as replacement of sand . The results show a better reducing in permeability of 1% F.R-5.5% HRWR-30%SL concrete . This reduction after 96 hours reaches 14.5% and 28.8% for crude oil and kerosene exposure respectively .

This research aims to study the effect of water properties (such as density and viscosity ) and heated water temperature on temperature distribution in Tigris river downstream Al-Duara power station . For this purpose a numerical model is applied for estimating temperature diffusion and distribution in river .
Momentum and energy conservation equations are used to describe the temperature distribution along the study area . The model incorporates the (K-ε) turbulence model to calculate the distribution of turbulent viscosity. The pressure distribution was determined using hydrostatic pressure equation . The partial differential equations were simplified to obtain the system of linear equations which were then solved using Gauss- Elimination method .
The numerical model is verified by the comparison of observed data from AL-Daura power station with those computed by the model .The comparison results show agreement with maximum absolute difference of (18%) and correlation coefficient of (0.925). The results show that neglecting the effect of density difference causes a longitudinal and vertical retardation of isotherms of about (12.5% and 50%), respectively. Assumption of constant viscosity causesa longitudinal and vertical retardation of isotherms about (10% and 60%) , respectively . Increasing the heated water temperature from 40 ˚C to 60 ˚C causes a longitudinal advance of isotherms of about (32%)

AISI330 stainless steel specimens, were coated by pack-cementation
aluminization, using single step-high activity process at 1000° C ; for 3,5, and
7hours. The plain aluminide specimens were then heat-treated for 5, and 50
hours at 1000°C. The three types: uncoated, plain aluminide, and plain
aluminide then heat treated specimens, were studied under cyclic oxidation at
1000°C for 240 hours in air. The results reveal that best results are obtained for 7
hours plain aluminide then heat treated for 50 hours specimen as compared to
other specimens.

Polymeric materials are increasingly replacing metallic materials as a result of their properties. In this work a composite of phenolic resin and caria species fibers and molasses was developed. The molasses has been previously alkalinized. The dough had been dried, milled and the particles classified in a range of grain sizes. Experimental assays were performed, varying the proportion of the resin and the reinforcement and the size of the particles, keeping the pressure and molding temperature constant. These composites were characterized according to physical and mechanical properties. The obtained results clearly indicat the extent of fiber-matrix interface adhesion. Fiber-reinforced composites show variation in their density, water resistance, compressive strength and hardness.

The ability of some different water-soluble natural and synthetic chemical compounds is evaluated to be used as dispersant for two types of kaolin, Merkhiat and J. Umm Ali. They are glycerin, glycerin jelly, poly(ethylene glycol) and Arabic gum.
The kaolin raw materials were grinded and fractionated by sieving process to five fractions to study the effect of different particle size on the final packing densities. They were had the following particle size: -90+32 μm, -90+75 μm, -75+63 μm, -63+53 μm, and –53+32 μm.
Sedimentation settlement under gravity was used to evaluate the quality of each dispersant. It was found that the type of dispersant and its concentration have an influence on the final packing density in addition to the particle size of the kaolin powders.

The stability condition of the plate heat exchanger (PHE) which is dynamically highly nonlinear can be limited by using the experimental phase plane technique. This technique proved to be better and more accurate compared with other methods which are needed to solve a set of theoretical complex differential equations to study the stability of PHE. The accuracy of this technique can be increased by increasing the numbers of on-line detectors which are implemented with digital computer.

In this work, the feasibility of using neural adaptive control with finite recurrent back propagation algorithm for controlling DC motor is investigated to capture the nonlinearity which is better than that of using back propagation algorithm. This was obtained from the results of the simulation adopted in this work .
The build-up of the simulation procedure is implemented by MATLAB

The chemical analysis of twenty one groundwater samples have been carried out to explain the recharge sources of various aquifers, and aquifer-aquifer interaction in the Pathri Rao watershed Haridwar District, India. The chemical composition of groundwater collected from the shallow and deeper aquifer shows that the existence of two types of water. This indicates that there are different sources of recharge to the shallow and deeper aquifers in this region. The electrical conductivity (EC) values of shallow aquifer especially in the Bhabhar zone (Upper Piedmont ) were high which also indicates that the shallow aquifers have recharge source other than deeper aquifers and the interconnection between shallow and deeper aquifer is poor to moderate in this region.

Merkhiat kaolin powders were dry grinded in ceramic ball mill, and fractionated by sieving process to five fractions. They had the following particle size: -90+32 μm, -90+75 μm, -75+63 μm, -63+53 μm, and –53+32 μm.
The effect of these particle sizes on the dispersibility of Merkhiat kaolin powders in the presence of different wt% aqueous solution of Arabic gum as dispersant was studied. It was found that the particle size of the dispersed kaolin powder and the concentration of Arabic gum dispersant play an important role in the dispersion process.

This research aims to study the effect of hydraulic river properties namely,bed roughness and water-surface slope, on temperature distribution of water released from South-Baghdad power station on Tigris River. For this purpose, a two-dimensional numerical model was applied for estimating temperature distribution and diffusion in the river .
Momentum Conservation Equation and Thermal Energy Equation were used to describe the temperature distribution along the study reach The model incorporates the (k-ε) turbulence model to calculate the distribution of turbulent viscosity .The pressure distribution was determined using hydrostatic pressure equation . The partial differential equations were simplified to obtain the system of linear equations that were then solved using Gauss-Elimination method .
The numerical model was verified by conducting comparison of observed data from South-Baghdad station with those computed by the model .The comparison results show agreement with absolute error of (17%) and correlation factor of (0.940).
The results of the study show that increasing the bed roughness from 0.02m to 0.06m causes a longitudinal retardation of temperature distribution by about (24%) and vertical advance about (20%). Also Increasing of the water-surface slope from 4 cm/km to 10 cm/km caused a vertical retardation of temperature distribution about (30%) and a longitudinal advance about (19%)

In this research the study of design parameters effect on thermal performance of packed bed which is used for heat storage was carried out. These parameters are thermal capacity of material which is used in thermal storage, mass flow rate of air using charging mode of unit storage, diameters of solid particles and relation between height and diameter of storage container.
A mathematical model was made for the problem and the governing equations for the time dependent temperature distributions in both the solid and fluid phase are solved by the implicit finite difference technique. A computer program in FORTRAN (95) was built to carry on the numerical solution. The results are expressed as function of design parameters and show good agreement with results of other workers. It is showed that the thermal energy stored is in direet proportion to thermal capacity and mass flow rate and diameter of storage container while inversely proportional to diameters of particles and height of unit storage.

A hydrogeologic study for Al-Jadrei Area in Baghdad, Iraq is made. The area is bounded by the Tigris River from three sides. A numerical model is developed to simulate the water table levels in the area. The limited available data of unconfined aquifer properties of three existing wells are obtained and interpolated over all the area of Al-Jadrei. On running the model for a period of 4762 days, it is found that GWL is increased by 6.6m near the location of the lake; the rises in water table levels are reduced gradually toward the east direction to be (0.1m) at Al-Hurria plaza and diminish at the eastern border of the modeled area.

This study is concerned with the static and dynamic characteristics of solid shaft supported by bearing with and without number of discs situated along the shaft. The effects of including and disregarding gyroscopic, axial load, translation mass and rotation mass inertia on the natural frequencies and deflection at the disc position have been studed.
The finite beam element model with four degrees of freedom at each node is used in this study, and a special computer programming was developed for the problem. Experimental work was carried out on a number of discs arranged along the shaft length, and the obtained results are compared with theoretical ones, which show good agreements.
This work and technique have shown good agreement with those of other investigators, and the computer program developed in this study proves to be quite efficient and can be used in the analysis of such systems

High performance concrete with compressive strength (40 – 120) MPa and other perfect properties is a new type of cementitious materials.
The research deals with the use of industrial by-product waste material as partial replacement of sand to produce high performance concrete with compressive strength higher than 40 MPa.
The result indicate that partial replacement of sand by industrial waste material (Brass) in addition of use of admixtures (Superplasticizer) and powder of pure silica gives high strength in comparative with reference mix.

Before selecting any alternative refrigerant for R-12, a performance study for a refrigeration cycle should be carried out using different types of refrigerants. A cold storage room of 3.8 kW capacity is used for this purpose.
Two types of hydrocarbon refrigerants, in addition too R-12, are used to charge the system separately. Namely propane (R-290) and mixture of R-290/ R-600a (68/32 wt.). Indoor loads are simulated by several halogen lambs. While the forced air cooled condenser of the unit is separated from the outdoor condition by a secondary air conditioning unit to control the condensing temperature. The effect of several parameters on the system performance and system matching are investigated. The results are presented for a cold storage room of 3.8 kW cooling capacity with a dimension of , and show that R-290 and hydrocarbon mixture give comparable thermal performance for the system, but hydrocarbon mixture could be suitable alternative for R-12 with out any modification in the system components that worked on the R-12.

Transfer function method is used to study the effect of local insulation
position in walls and roofs on cooling load in Iraqi building. room 4*4*3m with
east window on21stJuly located in Baghdad and made of local metals in walls
and roofs is used as case study. Many types of walls and roofs (with insulation
and without it) are used in different directions to study how the magnitude and
the distribution of cooling load an changed. The results show that using local
insulation (clay) in walls and roof reduces the cooling load by (23%)and the peak
loads reduced (10%), also the study shows that the insulation (any insulation)
used in eastern and western wall is more efficient in reducing the cooling load
than the southern and northern walls .
The results also show that when using the same amount of insulation in
walls and roof at the same time the cooling load distribution changes more than
when using this amount of insulation in each one. The study shows that when
using north and south window and using efficient (not local)insulation the
cooling load is reduced by (32%). This result shows the local insulation is good
and active in reducing cooling load.

Tests have been conducted with a newly designed force dynamometer which has a natural frequency 500 Hz and cross sensitivity ( to measure the forces accurately and separately ) is less than 2.5 %. The calibrated static forces of the dynamometer in x-axis direction is about 2500N and in y-axis direction is about 3000N with 50% safety factor.
The dynamic cutting coefficients are evaluated from the steady- state cutting parameters. Modifications are made in the feed/penetration rate factor in order to determine the dynamic chip thickness coefficients. An mathematical approach was also made for investigating of the dynamic cutting forces.
Dynamic instability occurs as a result of the chip thickness variations. The use of simple damper reduces the chatter and the cutting forces when increasing the feed .The simple damper has active vibration damping to dynamically stabilize the cutting process is the presented in this paper .
By using computer program , the desired stability charts of the machine tool structure for different cutting conditions is determined