Journal of Techniques

Studying the effect of reinforcement by carbon fibers as woven roving (°90-°0) with density (1.95 Kgm3) on mechanical properties of unsaturated polyester resin after reinforcing it by different percentage of fibers (20%, 40%,60%) and these properties included : impact strength , tensile strength , compression strength , flexural strength , and hardness . the Mechanical properties were carried out for unsaturated polyester resin before and after reinforcement by fibers, and studied the effect on the above mechanical properties as illustrated in the diagrams between mechanical properties and reinforcing percentage .

The present research has conducted so as to search for the new properties for a group of regular geometrical shapes of pictures, and to classify this group into categories depending on four features including energy, contrast, correlation and homogeneity all of which can be obtained from a co-occurrence matrix.
These four features have also been studied into details and then were vastly discussed and presented so as to show their effects respectively on the features characterizing the regular geometrical shapes. Besides, the algorithm applied has proved that these features can be extracted as new features for the regular geometrical shapes.
However, the experimental results of the proposed algorithm have proved that both energy and homogeneity features have given high recognition properties compared with the remaining other properties.

Reuse of Construction waste gives two aims, the first is to remove large quantities of pollution resulted from these waste, the second provides cheap resources for concrete aggregates. The current study includes testing many properties of concrete mix with local waste concrete as coarse aggregate, after removing coarse gravel , which means using mortar of this waste concrete after crushing, grading and washing.
Results show that this recycled aggregate has lower specific gravity and absorption compared with natural aggregate used in Iraq, also results show that the concrete prepared from this recycled aggregate has acceptable compressive strength and absorption and it has good flexural strength and low dry density as compared with concrete with local natural aggregate. this concrete is suitable for paving and blocks making.

Green open areas are those spaces developed gradually within the urban design of the old Arab cities .These areas started as an open space inside the residence unit. (The court), then grew bigger gradually to become inside the neighborhood and finally within the whole city .These green areas became the entertaining centers applauses environmentally and socially.
The current paper focuses on studying the types, classification and the total area of these green open areas ,as well as the ratio of these areas to the total area and population of Mosul, and whether this ratio fulfills the needs of the inhabitants to such kind of spaces. The paper also studies the social impacts and the importance of the green areas as entertaining places for the citizens of Mosul.
The green areas in Mosul were located by arial maps and were compared to the populations of Mosul according to global standards, in order to obtain the required results related to green areas which are required for achieving social entertaining as the main goal.

The realization of the connecting process between engineering architectural design and acoustic design for full elements is the basic to reach the optimum acoustic performance .The importance of acoustic design begin from selecting dimensions of architectural spaces and up to selecting appropriate carpeting to achieve a good sound. The research focused on about the important basic factors at the selection of hall dimensions. Three tests when conducted for three halls in Al Anbar technical institute newly constructed with different dimensions (length, width and height) and determination of the noising frequencies from hundreds of frequencies resulted variety of waves of resonance (axial, tangential and inclined) which make hall inefficient acoustically, then fixing it if found to reach a good efficient acoustic of the hall.
This research aim is to find a simple way to get an efficient acoustic performance through proportionality of selecting dimensions for the hall to reduce or prevent that sound coloring phenomenon.

This research show that addition of a dursban to concrete with 1% as percentage of water mixing will reduce the compressive strength of concrete with high percentage .
In order to reduce the percentage of decreasing compressive strength of dry mixes concrete with low workability by curing concrete completely or partially with curing water containing 1% a dursban .
Research shows that the decreasing percentage at compressive strength of concrete due to added 1% a dursbanfrom mixing water compare with compressive strength of reference concrete are equal to( 80% , 62% , 60% ) at ( 7,28,60 ) day from mixing date .
Also research shows that the decreasing parentage at compressive strength of concrete due to curing concrete completely curing water concrete with curing contion1% a dursban compare with compressive strength of reference concrete are equal to ( 4% , 8% , 9.7%) at ( 7, 28 , 60 ) day from mixing date .
Also research shows that the decreasing percentage at compressive strength due to partial curing concrete with curing water contains 1% a dursban for 7 days , then curing with ordinary water only until reaching time compare with compressive strength of reference concrete are equal to 9 4% , 2% , 1.25 %) at ( 7,28,60) day from mixing date .

The research use process capability index which is the most important statical techinqes to improve the quality where they can manufacture product with low percentage defect and it will be applied in welding wire which produced in Al -hilal industrial .and because the importance of extrusion process which carried out on the extrusion machine , and the large number of errors during this phase, will be determined the process capability index for this machine through the application of the methods of process capability .
The data were collected (sample size is constant )with constant period of time ,then the data were analyzed by (X-R chart) its clear that phase with controlled statically ,while the histogram has explained that there is dispersion in the data and exit from the upper tolerance limit by (80%)of data and the index was estimated up to (0.58) ,so it was needed to identify the causes that lead to improve the index by intensive following –up of extrusion process .
The results of research as the following : 1- The process was controlled statically. 2- There has been improving in process capability index . 3 -Dispersion of data is considered acceptable . 4-Eliminate the average normal dimension specified by the designer by (0.01mm). 5 -Low the percentage of defect out side the upper limit which became (3%).

The aim of research consists of an investigation into the suitability of drainage water in the area which is located at the north of Baghdad city (Al-Rashidiya & Al-Husainiya areas) for irrigation of agricultural crops.
The result indicates that the suitability of drainage water for irrigation of non-sensitive (high tolerant) crops , and the agricultural lands need to the drainage process when are using this water , because of the high rate of salinity and chemical parameters (chlorides and magnesium)

In the Present study , CuGaS2 alloys have been Prepared by mixing stochiometric weight of Cu, Ga and S , then melting them under vacuum of about ( 3 × 10-2 mbar) in a sealed quartz ampoule. The thin films have been prepared by depositing the alloy on soda glass substrate , heated at different temperatures and using the thermal evaporated technique under pressure of about (3 × 10-6 mbar ). The electrical conductivity , was characterized by two activation energies in the temperature range {(-120 °C) to 25 °C}. The maximum room temperature conductivity was ( 17.6 Ω-1.cm-1). From the Hall effect measurements the type of the carriers , the carrier concentration , and that Hall mobility , at room temperature , have been deduced. The films were of n- type. The maximum value of the carrier concentration were (9.1 × 10 18 cm-3 ) for films prepared at (150 °C) and the minimum value were (1.65 × 10 18 cm-3) for films prepared at (350 °C) , while the Hall mobility had maximum value (36.45cm2/v.sec) for films prepared at (150 °C) and the minimum value was (6.08 cm2/v.sec) for films prepared at (350 °C).

The creep behavior for unidirectional and bidirectional fiber composite material has been studied experimentally under the effect of different water acidity level (pH=5,7&10) and moisture percentage (m= 1.24, 2.02 & 2.65%). It has been observed that the creep strain increase when the moisture percentage increased and decreased with increasing the acidity level. Different values of the applied stresses are tested which gave an increasing in the creep strain values with increasing the stress. The experimental creep data can be fitted with the general exponent creep equation. This equation is modified where the effect of moisture percentage and the applied stress on the creep strain are suggested as variables in the creep strain equation. The suggested equation gives a good criteria to be used to describe long time of creep strain in this work.

In this paper, a proposed design of bandpass filter is introduced . A new stubs are applied to the bandpass filter to enhance the skirt selectivity on both sides of the upper and lower frequency band . Two attenuation poles are produced by this new structure. The upper band pole is introduced by the hairpin-comb structure. The lower band pole is introduced by the tapped open stubs. We fabricated a new structure using milling machine at the Lab in The University . two attenuation poles are realized at the upper band and the lower band respectively, one at 1.71GHz and one at 1.93GHz. Sharp roll-off on both sides of the passband is obtained. Measured results show good selectivity at both upper and lower bands

The effects of bearing pressure, sliding time, and sliding speed on dry sliding wear properties of AISI HNY3 internal combustion engine exhaust valve material were investigated. Experimental tests were performed by using a pin-on-disc apparatus. For all tests, pin was rubbed against silicon carbide emery paper of ASTM grit 180, which was mounted on rotary disc with varying speed 7.5 - 235.5 m/min, under varying bearing pressure 48.75 - 292.75 KN/m2.
Experimental results, revealed that wear rates increased with increasing bearing pressure, in three linear regions separated by transition points. In the first region, wear rate were low , and increased slightly up to the first transition point, and the wear process was mainly controlled by formation of fine dark oxide debris particles, with smooth and flat wear tracks. This region falls in mild wear process. Beyond this point in the second region , wear rates were increased and debris particles became both metallic and oxidative, with rough wear track surfaces, and this region represents the transition zone from mild to severe wear. In the third region, wear rates were largely increased, and large metallic wear debris had been delaminated from the sliding surfaces, with rough and deep wear tracks in which severe wear had been formed. It was also concluded, that wear rates decreased with increasing sliding speeds.

The paper presents the effect of pH and concentration of glycol solution and other general operating problems and some important trouble shootings which are concerning and involved with the operation and performance of the different equipment of the gas dehydration plant by using glycol system. The trouble shooting deal and diagnosis of the problems encountered during plant operation with the main equipment like High Dew Point of Sales Gas, Low Glycol pH (Less than 6.5), and Lean Glycol Low Concentration. Also many tips and recommendations regarding the operation performance of the dehydration process has been added.The work included three Libyan gas fields ( North Zelten, Meghil, and Sorra plants).

This paper presents design, modeling, simulation and hardware implementation of a separately excited Direct Current (DC) motor speed control using Field Programmable Analog Array (FPAA) technology. The hardware consists of a DC motor system, Proportional-Integral-Derivative (PID) controller using FPAA kit, power module, and tacho-generator. The results show that there is a reduction in overshoot, settling time, rising time and steady-state error compared with the conventional PID controlled system. The proposed system has been simulated using MATLAB software to study the effect of adding a PID controller on the factors affects the DC Motor speed. The model results show enhancement in the overshoot, settling time and improve the steady-state and transient response of the system

Experimental and analytical works were done in order to study the effect of different curing methods and determine the best curing method which characterize the mechanical properties (compressive strength) of Reactive Powder Concrete (RPCs), in order to use it in rigid pavements (Airport Pavements) in Iraq. RPCs specimens were subjected to five types of curing regimes, Modified Curing (C1), specimens are immersed in hot water at 60oC for 7 days starting at one day after cast, specimens are then stored at 23oC & 100% RH until testing, Normal Curing (C2), specimens are allowed to remain in a standard environment conditions (23oC & 95% RH) starting at one day after cast until testing, Delayed Curing (C3), specimens are subjected to Normal Curing (C2) for 10 days after casting then specimens are subjected to Steam Curing (C4) for 48 hours, Steam Curing (C4), specimens are subjected to thermal steam treatment for 48 hrs at 90oC & 100% RH starting at one day after cast, specimens are then stored at 23oC & 100% RH until testing, and the Steam Pressure Curing (C5), specimens are autoclaved at 120oC & 1.0 MPa for 3 hours starting at one day after cast, specimens are then stored at 23 oC & 100% RH until testing. Test results show that the highest compressive strength were obtained by both the C1 and C3 curing methods. Depending upon mix proportions and age of test, the percentages of increasing in the compressive strength of RPCs specimens with respect to curing types were as follows: (a) For mixes without polymers: C1 recorded (59.03, 14.69, 32.16, and 14.67)% higher 28-day compressive strength than (C2, C3, C4, and C5) respectively; and C3 recorded (39.42, 20.70, and 23.38)% higher 28-day compressive strength than (C2, C4, and C5) respectively. (b) For mixes with polymers: C1 recorded (20.99, 5.83, 30.59, and 26.07)% higher 28-day compressive strength than (C2, C3, C4, and C5) respectively; and C3 recorded (28.59, 38.78, and 57.34)% higher 28-day compressive strength than (C2, C4, and C5) respectively.

This paper presents a comprehensive experimental study on the resistance of concrete made of partial or full replacement of natural fine and coarse aggregates by recycled aggregates to internal sulphate attach as the main problem in concrete production in Iraq . The replacement and sulphate levels added were the main test variables in this study. The sulphate levels investigated were (0.5 , 1.0 , 2.0 and 2.5%) of fine aggregate weight in addition to that of control sulphate level, while the aggregate replacements levels were (25, 50, 75,and 100%) of those natural fine and coarse aggregates weights. The variations of linear expansion and compressive strength were measured carefully and periodically up to the age of 180 days for both natural and recycled aggregate concretes .
Results indicated that , partial replacement of (75%) level by recycled coarse aggregate or recycled fine aggregate was practically possible without impairing the concrete resistance to sulphate for all SO3 levels up to (1.0 and 2.0%) respectively at all the ages studied . Full replacement level by one type of recycled aggregate on the (1.0%) SO3 level was practically possible at all the ages studied . Full replacement level by both types of recycled aggregates must be done in the lower SO3 levels up to (0.5%) at all the ages studied. Fifty percent replacement level by both recycled aggregates was practically possible for the all ages and SO3 levels up to (1.0%)

Clay pot method is one of the most efficient traditional systems of irrigation known and is well suited for small farmers in many areas of the world. Pot irrigation system consists of unglazed clay pots; each has many micropores in its wall. The microporous wall guides water seepage from it in the direction where suction pressure develops. When the clay pot buried in the soil, filled with water and crops planted adjacent to it, the pot effects sub-surface irrigation as water seeps out of it due to suction force which attracts water molecules to the plant roots. Field experiments were conducted to quantify the effect of pot volume on water use efficiency and surface wetting edge by comparing the performance of large pots to that of smaller ones. Two types of pot irrigation systems, the first type consists of pots with large volume "PIS1" and the second type consists of pots with small volume "PIS2", were prepared in a clay loam soil by using three crops, namely, tomato, beans, and cucumber. Results showed that water use efficiency when applying "PIS1" was greater than that of "PIS2" for all crops used in the experiments. The crop yield under "PIS1" is higher than that of "PIS2" but it requires much more water for all crops. "PIS2" is a water saving system compared to "PIS1". A positives and significant correlations were found between surface wetting edge and time of seepage opportunity with R2 of 0.96 and 0.93 for large and small clay pots respectively. Results indicate that it is possible to use clay pots with various volumes to consist pot irrigation systems, considering that using pots with small volume leads to decrease water use efficiency and surface wetting edge.

The paper contains a concise but clear description of the spillway hydraulic design in connection with flood attenuating dams. The unsteady continuity equation is fundamentally used for the reservoir routing procedure, where a general computer program was prepared for solving the routing system.
For the routing procedure, it is assumed that the spillway is of the free flow ogee type operating as a rectangular weir. If a bottom outlet is used, an orifice type equation is the governing one. However, the bottom outlet influence on routing was insignificant in comparison to the free overflow discharges.
A specific realistic problem is solved, and full details are given showing the influences of various parameters influencing both design details of dam and operating schedule of the reservoir. These influences were summarized in a nomograph. This nomograph is very handy in the quick design considerations. The actual dimensioning of the spillway based on the routing procedure is full presented showing the complete aspects of handling such problems

This paper presents a design of a multi input single output fuzzy controller (MISOF) to control the speed of a DC motor. The new technique used in this work is by inserting besides the Proportional Integral fuzzy controller another input (wr), which will decide the required base rule in order to get the required firing angle for triggering the thyristor bridge. In this paper, the MISOF controller is designed to control the armature voltage in order to maintain the motor speed. The fuzzy system decides the region of operation according to the required speed, also use the error and change of error of the speed to control the system speed. Simulation results show that the speed response of the DC motor controlled by the MISOF controller have a zero overshoot and zero steady-state error for different values of the reference speed. The paper describes application of fuzzy logic controller in a speed control system that uses a phase-controlled bridge converter and a shunt dc machine.
Index terms: - DC motor drive, controlled rectifier, speed control, fuzzy logic controller, PI controller.

The effect of hole made in plate (subjected to concentrated force) on the deflection and maximum stress is studied. Different hole sizes and distance from the plate center(x) are tested experimentally and compared with a reference plate without hole. The specimens are classified in to two groups; the first represents the specimens which contain hole leis in the x-axis of the plate and the second group represents the specimens which contain two half hole leis at the edge of plate. The results are analyzed analytically, which give a good agreement with the experimental deflection data. The first and second group with the same diameter gave a lower deflection than that for the plate without hole for the same cross sectional area. Increasing hole diameter gave a reduction in the deflection values for the specimens in each group. The second group of specimens gave a higher deflection values for a wide range of (x) as comparing with those of specimens in the first group. The maximum stress (σx) is higher in the specimens of the two groups as comparing with the reference plate for wide range of (x). When this distance (x) increased, the value of maximum stress is reduced for the specimens of the two groups. The same behavior is found when increasing the hole diameter.

In this research, the rectangular patch antenna dimensions are reduced by means of the Genetic Algorithm. Genetic algorithms are capable of handling a large number of design parameters and work for optimization problems that have discontinuous or non-differentiable multi-dimensional solution spaces, making them ideal for antenna optimization. In the present work, a genetic algorithm has been used for size reduction in microstrip patch antennas. A method for reducing the size of microstrip patch antennas by up to 45% by removing rectangular slots from the metal of the microstrip patch is presented. A solid patch antenna that resonates at (8.5 GHz) is forced to resonant at (10 GHz) through the removal of the different shaped slots. Given the number and shape of the slots, the genetic algorithm is used to optimize the size and location of the slot on the patch.

The major impairments of the mobile wireless communication signal are Fading and Doppler effect. To reduce these effects, channel coding is required which provides for forward error correction. This enables the receiver to correct the errors which have occurred in the transmission path. Also, a control information consists of known pilot bits may be added to support channel estimation for coherent detection.
In this paper the Bit Error Rate (BER) performances is shown by means of simulation for Rayleigh fading channels with Doppler shift and Additive White Gaussian Noise (AWGN) is added. Here the convolutional code with ½ code rate is used as a channel coding technique, and sequence of pilot bits is mapped and inserted with known modulation scheme Quadrature Amplitude Modulation (QAM), these pilot bits are know to the receiver. At the receiving end coherent detection is done by channel estimating using the splited pilot bits, and then Viterbi decoding is investigated. Obviously, the results show that the performance in terms of BER of coded signal is much better when inserting pilot bits during signal modulation. To compensate the loss in spectrum efficiency and data rate, the use of QAM modulations with larger size constellation is suggested, with small loss of performance associated with an extended constellation. The whole work is done using MATLAB.

The objective of this paper is to perform an experimental study of free convection heat transfer from staggered pin fin-arrays on heated base plate. The experiments represented by studying three orientations of the fins (upward, downward and sideward). The results showed that the sideward orientation gives better results as compared with other orientations. Nusselt number determined as a function of Rayleigh number at Prandtl number approximately equal to (0.7) for all tests, Rayleigh number in this study ranges between (1.877×103 ≤ Ra ≤ 8.086×103) . From the results the heat transfer coefficients of the heated plate in sideward orientation are about (8%) greater than those for the upward orientation and exceeds that of downward facing by (24%). Also the orientation effected in the distribution of temperature along the fins. The results shows that the temperatures along the fins in sideward state have an uniform distribution, while in upward orientation the temperature along the fins increased in location nears the base plate, this behavior becomes very clear in downward orientation because of the impeding in moving hot air.

The paper deals with studying and analyzing of the affecting factors on the performance of an old steam boiler operated manually, such as operational parameters deviation and human errors that include operational, maintenance, and test staff, and the influence of those factors in the sustainability of the steam production and their impact on other boiler components.
Engineering safety analysis method (front and back analysis) had been used to study those factors and to find points of failure, and to clarify the relationship between the types of failure and possible events, which facilitate reliability analysis technique.
A PC program in visual basic language was designed as a tool to perform periodical evaluation of boiler reliability and its operational systems, draw boiler reliability as a function of time, and the variation of boiler failure rate with time.
It is found that the maximum failure rate of the boiler under consideration is (0.000742) and it occurs when the operation time reaches about seven months. After that the boiler failure rate will be constant.