Journal of Techniques

The aim of this research is to study the manner of alumina (Al2O3) particles dispersion with (2-10) mm size in (Al-7%Si-0.45% Mg) base alloy melt employing of classical casting method. The mechanism of particles diffusions by melt turning and stirring that makes vortexes help the particles entrance in the matrix of base alloy also has been studied. The samples of metallic composites (MMCs) with dispersed particles percentages (4%-6%-8%-10%-15% and 20%) are prepared. The effect of the particles dispersion on the mechanical properties of produced samples were carried out by tension & hardness tests. It is found that the ultimate tensile strength of the produced composites can be increased by increasing of the percentages of alumina particles in the matrix of the base alloy. It becomes (232 Mpa) at (20%) of added particles. The results showed that the average hardness of prepared samples increasing with increases the alumina content. Microstructure study of prepared samples was carried out. The results showed particles location and distribution of it in the matrix of base alloy. The dissolution of Alumina particles into liquid base alloy was clear in some cases.

The need to produce high performance concrete led the researches to try to
exploit the potentialities of natural or artificial materials so as to improve the
performance of concrete . Iron furnace slag has been used as an alternative of
proportion on cement after being processed , since its main oxides are similar to those of
cement .
In this investigation , the effect of slag was studied including compressive
strength and absorption of concrete in 7 , 28 days were investigated .
Results demonstrated that the inclusion of 6% slag as a partial replacement by
weight of cement showed superior performance over those of the other concretes ,
where the percentage increase in compressive strength after 28 days relative to reference
concrete was 19.5 % and the percentage reduction in absorption was 32 % .

In addition to the Temperature rising in the summer season, the large
employment of the domestic refrigeration and air-conditioning equipment playing big
role in increasing the peak load demands for the national electrical system and the usage
of refrigeration and A/C systems consuming low energy (Low running cost) contribute
in decreasing the peak load demands. As soon as the traditional direct expansion
systems consume high energy, we suggest dual system composing refrigeration part as
well as evaporative part consume less power than the traditional one, with respect to the
same cooling effect .
We studying the energy efficiency ratio (EER) for the suggested system ,the value
of (EER) is (2.5) higher than that of the refrigeration part (1.8) and its less than that of
evaporative part (12) .
The Effectiveness of the dual system is (60-70)% its higher than the evaporative
part (15-20)% and refrigeration part (40-42) %.

The purpose of this work is to study the microstructure of the bonding zone between
the low carbon steel (ASTM A36) and the pure copper (OFHC) by two welding process,
brazing and soldering.
In brazing process, two types of filler metal alloy were used, namely (DIN SCuZn40Si)
and (AWS LCuP-7), while in soldering process only eutectic soldering filler
of (Sn-Pb) was used. Oxyacetylene gas welding technique has been used in welding of
Lap-joint type.
Microscopic examinations showed that there is a clear bonding phase and interface
in brazed joints , while welding by soldering have no such features. It was also apparent
that the high chemical effinity between the filler metal alloy and the base metal will
reduce the existence of defects in the bonding zone.
Key words: Microstructure , Brazing , Soldering , Copper , Steel

The research study includes an analytical approach to indicators of quality
standards that can be adopted to assess the axes of the educational process in the
institutions of engineering education within the indicators of the study comparing the
realistic , and desired estimates.
These indicators can be used to judge the quality of higher education institutions
to improve , recite , and develop it .
The findings of this study need to put this into practice on the standards for use in
evaluating the quality of Iraqi educational institutions in the future

In this study , an analytical study was done to indicate the characteristics of
industrial sewage which produced from Tannery Factories , and their effects on Tigris
River .
This study was continuoued over a period of one year . Many tests were conducted
such as (TDS , TSS , DO , PH , BOD , TH , CL , NO3 , PO4 , S ) by using chemical
methods. Results showed that some of the pollution parameters such as TDS , BOD have
effects on char of Tigris River with monthly increased about 69% , 80% respectively.
These ratios had reached max. values at summer and autumn seasons .While other
parameters does not exceeds the max. permissible limits . Researchers suggested to control
the quality of sewage produced from the Tannery Factories , must be arranged the using of
chemical compounds in processes of soaking and fleshing the hides also used an ion
exchanging units to control the value of TDS .

Samples were collected from the Al-Hamdan treatment plant and Al- Brahtyia water
supply plant. The samples were collected from three locations in each plant they are
"input, sedimentation tank, and out put) for a period from July 2008 until June 2009.
For the measurement of some physical, chemical and algological parameters in both
stations.
A total of (30) species of phytoplankton were recorded. Among the study of the
percentages of the different algal groups showed an increase on the blue-green algae
follows by green algae which promotes the presence of organic pollution.
Diversity was calculated using the Shannon and Wever index (H'), the diversity
of plant Brahtyia more diverse algae species from Hamdan station ,may be due to the
availability of nutrients and environmental factors such as potential Hydrogen (pH) and
,Temperature appropriate for the growth and sovereignty of these algae while affected
by plant Hamdan sewage water rich in eutrophication with a low number of species.

The research included two tests, compressive strength and absorption on two different types of thermostone ,first type without finishing , second with juss and gypsum finishing, tests were done on these samples under regular and high degree of temperature (300,400,500)C° as heated samples were tested and left to cool in air and then in water to simulate the fire condition.
Results showed, compressive strength of thermostone reduce with the percentage of changes in temperature and the finishing layers depending on the changes of cooling condition as percentage of reducing in compressive strength increased with the increasement of temperature for the samples without finishing , the higher percentage was 29% at temperature 500 C° and the existence of finishing layers reduces the effect of heat on compressive strength the percentage reduction was (51.8,15,19.8)% for temperature (300,400,500) C° respectively ,for cooling condition , the thermostone samples exposed to high heat after cooling in water showed a specific reduce in compressive strength in high percent comparing with heated samples which cooled with air . the results also showed the absorption percent for samples without finishes is higher than those samples after removing finishing with temperature (,400,500)C° was (7.95,6.43)% respectively, the absorption percent of thermostone was only measured, so there was no possibility to measure it at (300)C° that means the presence of finishing reduces water absorption of thermostone .

The aim of this research is to study the possibility of the use of Nitrogen fertilizer solution as a quenching medium for medium carbon steel Gr 1042 and low alloy steel Gr4140 and its effect on mechanical properties of both steels. The heat treatment were conducted which include heating the steel to (850-900) Ċ for (10 &15) min. respectively and then quenching into Nitrogen solutions. Results showed that the Rockwell hardness values of both steels employed in research increases with the increasing of the Nitrogen fertilizer solution concentration while retaining an acceptable impact strength. The results shows that the Nitrogen solutions have high cooling rate in diffusion transformation region, and this ensure that any part of the austenite does not transform pearlite in its various forms.

In the present research work, a field study was performed to the both Jambur (north & south) parts petroleum (Oil & Gas) field. The study includes the associated gas analyzing by using the Gas Chromatography ( VARIAN CP-3800 GC ) instrument .The results showed that the associated gas production of the south part is more than (230 MSCF/day) and methane is about (80%) of the total production with free (H2S) in this part. The production of the north part is more than (170 MSCF/day) and methane is about (80%) with (8.61%) of (H2S) at the first stage of production which reduces to (3.81%) at the second stage and to(0.0%)at last stage .The research indicates the possibility of using the associated gas for several purposes such as power plant operation ,petro-chemicals, or exporting after changing it to (LPG) or (CNG) by using the new technical processing to reduce the losses especially (CH4) which are about (40%) of the total production .

Green areas play an important role in urban planning because of their effect on the environmental. The main objective of this research is to evaluate the spatial distribution of green areas among the neighborhoods of Hilla city. Two criteria had been used, the first was the ration of green area with respect to whole area of the land uses, the second was the individual share (m2/Inh.) of green area. The main conclusion of this study was the high variation in the green area allocated, because of the existing of plam forests around and within the city and the bad allocation of this use (green area) in the city master plan.

The aim of this work is to study the effect of welding stresses induced by heat affected zone (HAZ) on the weldment toughness. Two types of welding electrode (AWS E6010& AWS E6013) are used to weld the specimen. In which the notch is machined at the weld metal for the specimen at the HAZ (x=0.0 mm), (x=5 mm) and (x=10mm) at region near the base metal measured from the center of specimen. The welding operation is achieved at three values of currents for each electrode type, such that the current values are (I=70, 80 & 90Amp.).
The results indicated that for the weldment tested for type (E6010), the impact energy increase gradually during increasing the current, and for type (E6013), the energy decrease gradually with current. That means the current has an effect on the stress on the weld mental. The results also illustrate that the increasing in the stresses was found in the higher current in the welding wire (E6010) as comparing with (E6013) for all values of the welding distance (x).

The aim of the present work is to investigate the mechanical properties and macrostructure of butt joints friction stir welded (FSW) specimens welded with two subsequent passes (one from each side).The material used is AA2024-T3 aluminum alloy 5 mm thick .Pin rotational speed of 900 rpm and 25 mm/min feed is used in this work .
The two passes either interferes each other by 0.5 mm or a gap of 0.5 mm between them is existed. The welded specimens have been tensile tested at room temperature in order to analyze the mechanical properties with respect to the parent metal. The macrostructure of the welded specimens has been studied by employing optical microscopy. Micro-hardness examination is also performed on the welded specimens.
The two passes FSW specimens with 0.5 mm clearance showed higher yield stress and less percentage elongation than the others ,while specimens with 0.5 mm interference showed higher ultimate tensile stress and higher percentage elongation.

A novel approach has been presented to detect and classify multiple sclerosis lesions in magnetic resonance images by using the cumulative Intersection method estimating the local fractal dimension for these images and allowing to distinguish between different types of brain tissues with respect to the human perception of roughness and statistical step - similarity of the under lying structure the offset of the Cumulative Intersection method in combination with the dimension are able to detect and distinguish lesions from other tissues by design the program Visual Basic V.6 . Also design the program to enhancement the images after reading the fractal dimension by using the genetic algorithm for resolution and high accuracy.

This paper investigates the effect of using high reactivity metakaolin (HRM) on the properties of high performance steel fiber reinforced concrete . Compressive strength , splitting tensile strength , flexural strength , Impact resistance and absorption for five mixes were investigated . HRM content used in this study was 5% , 10% and 15% as a partial replacement of cement with 2% fibers by volume of concrete .
The results indicated that the reference concrete reinforced with 2% steel fibers by volume showed a significant increase in splitting tensile strength , flexural strength and impact resistance, the percentage increase after 60-day relative to reference concrete were 29.6% , 30.7% and 179% respectively .
The results also showed that the incorporation of 10% HRM as a partial replacement by weight of cement with 2% steel fibers showed considerable improvement in all properties , the percentage increase in compressive strength , splitting tensile strength , and flexural strength after 60-day compared to reference concrete were 12.3% , 46.8% , and 46.5% respectively .

A numerical study has been done to evaluate the utilization of a water pipe buried inside an external wall to reduce the heat gain and prevent the transmission of heat energy inside the conditioning space in summer season.
The result of this paper shows that the reduction in heat gain could be occurred with specific values of parameters like a number of pipes per square meter, a ratio of pipe diameter to the wall thickness, and a pipe inlet water temperature.
Comparing with normal wall (without pipes), the result shows a significant reduction in heat gain which is about 82% when number of pipes per meter of wall length is 3.0 , the ratio of pipe diameter to the wall thickness (D/W) is 0.20, and the water inlet temperature is 25°C while the minimum ratio of reduction 24% is achieved when a number of pipes per meter , the ratio of pipe diameter to the wall thickness, and the water inlet temperature are 3.0, 0.2, 20°C respectively. The results also show that there is a very small effect of pipe center position inside the wall on the final heat transmission.

Due to enormous growth of Wireless Personal Area Network (WPAN) service, the need of a new engineering technique that can transmit high data rates arises. With its wide bandwidth, Ultra Wideband (UWB) has the potential to offer much higher capacity than the current narrowband system. In this research, a new Rake receiver for a pulse based UWB communication system is proposed in a multipath channel environment to mitigate the multi-user interference (MUI). The conventional Rake receiver is capable to mitigate the MUI to a certain limit because it contains only one decision unit. The proposed Rake receiver is based on modifying the conventional Rake receiver in order to mitigate the MUI by using three-stages-decision unit. The results are illustrated by using Matlab program that validate the proposed Rake receiver. Theperformance of the proposed Rake receiver is evaluated using a Partial Rake (PRake). The Bit Error Rate (BER) performance of the proposed Rake receiver is improved as compared with the conventional Rake receiver.

This work involves a design and study of using lithium bromide solution for dehumidification of moist which is necessary for good evaporative cooling which is popular and have extended use at the southern part of Iraq. At dehumidification unit (drying unit), Lithium Bromide solution atomized from drilled holes as droplets in the air stream to absorb moisture. The weak solution then collected and heated electrically to get strong solution which is pumped by 1.5 Kg/Cm² through (water-solution) heat exchanger of tube within tube type to eliminate its sensible load. Test was done during the period of July month and for 6 hr daily. The dried air then passed through heat exchanger ( air-water) to eliminate heat of absorption. Then the air was passed through an evaporative cooling unit and then forced to the space to be conditioned. Temperature and humidity of the air stream was measured at inlet, after humidification, after heat exchanger and at outlet of the system .The basis used in this work about the air leaving the unit is the comfort zone on psychometric chart. The work was done with and without drying unit to make comparison. It was found that all uncomfortable conditions of air through the test entered the comfort zone by using a dehumidification unit, and the dehumidification unit can be stopped when the relative humidity of the outdoor air decreased below 25% at July. It was found also that the unit become more efficient at midday time.

Wall chlorine decay occurs when chlorine react with the wall material itself and with adhering biofilms. The wall decay constant is mostly a function of pipe characteristics: material, inner coating, age, diameter and presence of attached biomass, therefore wall decay constant (K) is more difficult to determine because it depends on a number of variables. In this study, the continuous flow experiments were performed to determine wall chlorine decay rate and its dependency on water flow rates and pipe diameter. The results show that wall chlorine decay rate can be expressed using first order model and the important parameter which effect on wall decay constant is pipe's material, as flow velocity increases, wall chlorine decay rate increases and as pipe diameter increase, chlorine decay rates decrease.

Analytical assessment of heat pipe's thermal performance is the objective of the present work. A new direct and explicit thermophysical term is essentially proposed for the first time, based on the main role of heat pipe's effective thermal conductance. This work provides a unique view into preference and selection of heat pipes of different designs, or between wicking and wickless heat pipes. Calculation of the derived Preferential Factor is mainly classified on the basis of application's purpose. Three main computational classifications are distinguished: sizing design, end differential temperature and thermal rating, in fhis tendency, analysis of influence of some dimensionless parameters on effective thermal conductivity (K) and preferential factor (PF) is considered for conventional cylindrical heat pipe and closed two-phase thermosyphon, at various working fluids: water (H2O), heptane (C7H16) and ethanol (C2H5OH). The corresponding affecting parameters include: operational temperature, length ratio, wick structure thickness (number of wick layers), thermosyphon liquid fill ratio and envelope material. The results indicated significant generic controlling parameters and specific limiting values. In the range of the three classified design cases and studied conditions. Changing the type of tube material, has no effect on preferential factor, while influence of working fluid type is different, and ethanol exhibits higher and sudden changes.

The work presented in this paper concerned with the design of a new remote control system, which can be used for controlling the on/off of home/office devices using mobile phone. The design consist of two main parts, the first part is a remote mobile phone used to select the home/office mobile and choose the selected tone code (0-9, *, #) from the user according to the selected device. The second part consist of a practical design which contains the fixed mobile phone connected with Dual Tone Multiple Frequency (DTMF) detector, delay and answer circuit and decoder to complete the function of responding the calling and analyze the tone code for control the selected device depending on tone analyzer of DTMF. The practical design which consists of DTMF, decoder and flip flops was implemented using Field Programming Gate Array (FPGA). The system has been worked in high speed action when implemented in Spartan FPGA package and good results have been recorded

Ultra-wideband (UWB) communication systems occupy huge bandwidths with very low power spectral densities. This feature makes the UWB channels highly rich in resolvable multipath. To exploit the temporal diversity, the receiver is commonly implemented through a Rake. The aim is to capture enough signal energy to maintain an acceptable output Signal-to-Noise Ratio (SNR) .In this paper, the performance of a modifiedPartial rake (PRake) receiver for an(UWB) communication systems is studied . The modification is based on adding a common single finger whose output is fed to multi-comparators distributed along the conventional PRakefingers. ABinary Phase Shift Keying – Time HoppingUltra-wideband (BPSK/TH/UWB) signal is used , in multi user environment ,this study is done on the Wireless Personal Area Network (WPAN) IEEE802.15.3a, CM3,(which is prepared in Matlab program using m-file code). The Simulationresults based on a Matlab code programs show the effect of modification in terms of Bit Error Rate (BER) enhancement. The results show improvements in the BER in both single user and multiuser situations

Sensorless field oriented control of linear Induction Motor (LIM) as one types of vector control has permitted fast transient response by decoupled motor torque and flux control. The stator windings are described by coupled differential equations using mathematical transformations to decouple variables and refer all the variables to a common reference frame. The speed error is measured of applied load and according to error value, the set torque increases which requires increase in q current due to its direct relation with torque. In this paper, the velocity remains approximately constant during the interval of load application. The fluctuation of torque and motor current vanish, with increase in the stator current

A general computer program listing is developed that can mathematically simulate one, two, and three dimensional non-steady advection-dispersion contaminant transport in a heterogeneous subsurface media. Programming techniques, involving time varying, point, line and/or area sources of contamination but not a pulsing contamination on the media.
The discussion of the modeling digital techniques includes the necessary mathematical background documented program listing, and job setup procedure. A finite difference approach is used to derive and formulate the equations of advection dispersion phenomena. A modified alternating direction digital implicit method is used to solve the set of resulting finite difference equations. The program included is written in FORTRAN IV and operates with any set of units. After the model has been run, it is found that the pollutant of concentration 1000mg/liter at the western polluted boundary reaches the river with concentration of 96mg/liter after a period of 905.6days since the model started

This paper outlines the method of producing high strength light weight cellular concrete using new simple method in production. An experimental program was conducted to determine the compressive strength, density, and absorption of this concrete. Cubes were tested in compression and other properties, and the results were compared with other types of cellular concrete produced by other methods. The results show that the use of water crystal beads with the addition of silica fume and superplasticizer with different percentage gave three types of cellular concrete : a – structural ( 20.87 ) MPa , b – moderate ( 15 ) MPa , and c - insulated ( Less than 11 MPa ) .