AL-Rafidain Engineering Journal (AREJ)

This research includes experimental investigation and theoretical simulation which is manufactured locally in a laboratory to assess the characteristics of the two-phase convective heat transfer and performance of a loop thermosiphon. Practical experiments were performed using pure water, hydrocarbon fluid (acetone) and a mixture of both fluids with determined weight ratios used as working fluids. The experimental results of average heat transfer coefficient that were theoretically simulated under the same boundary conditions in both cases to study the effect of the kind of working fluid on the period required to reach the steady state condition and to achieve high performance within the best design conditions of the experimental rig. A comparison was made between the simulation and experimental results and an acceptable agreement was shown. It is worth mentioning that the Computational Fluid Dynamic analysis (CFD) with Engineering Equations Solver (EES) were used in the theoretical simulation.

The main objective of this study is to investigate the experimentally the coefficient of discharge for three baffle sluice gates and compared with single gate. The channel slope was changed tow times (0, 0.0075). For this purpose three baffle sluice gates were made from fibber class with (1cm) thick, (30cm) wide and (15,25,30)cm height for first, second and third gate respectively. The three gates have been sharp edge from the top and bottom with 2mm thick .The distance between the three parallel baffle gates were changed three times (2, 3.5, 5) cm. The analysis of results showed that discharge coefficient Cd in horizontal channel is larger than its value in inclined channel with direction of flow and the change in space between gates didn't cause an important difference between values of discharge coefficient Cd. The values of Cd were between (0.561 -0.736) for horizontal channel and three gates, while when the channel inclined the values of Cd were between (0.523-0.662) for three gates.

Gas turbine blades are suffering from failure, most of the studies indicate that 50% of the failure and breakage due to its complexity circumstances, The aim of this work is to analyze stresses at the first stages in AL Mansourgas power station in Mousl city, (AUTOCAD) which is computer program has been used to draw the blade at the exact measurement, where three kinds of different shapes of blades have taken, The real blade solid and hollow airfoil at the root, hollow airfoil at the root, Solid Airfoil at the root(AUTOCAD) program has been used to obtain the cross section area at any height along the blade lengths, (MATLAB) program has been used to obtain equations between cross section area and the height along the blade then determine the centrifugal force for a three blades used in this research. The study concluded that the real blades,solid and hollow is best because it garantee a minimum normal stress.

Blades may be considered to be the heart of turbine without blade there would be no power and the slightest fault in blade would mean a reduction in efficiency and costly repairs.The centrifugal force is one of the problems faced by the designer of blades especially at the first stages. The designer aims at reducing the stresses with in the allowed limit.The ANSYS 15 software was used as far as it is the most effective in analyzing the different numerous cases of stresses, the blades with limited root in all direction (X,Y,Z) were taken into consideration . The centrifugal forces were applied on the rotor blades at running speed of 6000 r.p.m., The finite element models of the blade were constructed using D3-10-noded Tetrahedron elements shape, SOLID 187, mesh of the entire blade 23406 Node,136575element. The average of normal stress, Von misses, Maximum principle stress, Minimum principle stress were calculated according to ANSYS 15 program, these stresses are as the result of the effect of centrifugal force for all planes along the blades and then values of stresses were compared to the curves for each alloy.The current research concluded that the Titanium alloy is the best alloy used in terms of reducing stresses due to centrifugal force, that is because density of Titanium alloy used is less than that of other used alloys, leading a reduction in centrifugal forcess that are directly proportional to mass.

An experimental study was carried out to deal with using a weir with circular holes to control the scour occurs behind it. The holes are located near the bed of the channel, their geometric details had been changed in its size, number and their distance from the bed of the channel. The channel bed was lined by crushed gravel with average diameter 11.1 cm. The thickness of the crushed gravel layer was 22 cm and its length was 4 m. There is 18 cases were conducted. Which the diameter of the holes were 1.6, 2.3, 3 cm, and for each size of them, the distance of the holes was 0, 0.25 or 0.5 cm, their number was one or three. These cases were compared with the case of using weir with no hole. The main hydraulic variable was the discharge, which five different discharges were flowed for each case. The total number of the experiments was 95. The dimensions of the scour hole behind the weir was measured as well as the water surface elevation in the upstream of the weir. The analysis indicated that the discharge plays the main role to increase the size of the scour hole. Using the weir with holes helps to decrease the scour occurs behind it, because the flow from holes interrupted the flow fallen from over the weir then some of its energy was dissipated. The diameter of the weir's hole that caused the smallest scour was 0.115 cm, while the most effective distance of the this hole to cause the same effect was 0.5 cm, among all the studied cases. Due to its height increases the dissipation of the energy of the falling flow.

Composite materials become more attractive for researches because of higher strength to weight ratio. As a result, many papers have recently published in this field. The current study deals with improving the resistance of hybrid laminated composite beam under critical buckling load. A number of carbon layers under various orientation angle and positions of hybrid fiber coupled with glass epoxy layers have been studied analytically and numerically. Firstly, an analytical model is presented by using Euler's theory to determine critical buckling load. Then, a 3D finite element models for the composite beams have been simulated by using ANSYS commercial program. The results show a very good agreement between theoretical and FEM (finite volume method). The critical buckling load, shows a proportional with increase the carbon layers number as same time the critical buckling load value shows a valuable decrease when the position of carbon layer insert towards the mid-plane more ever, this value various with orientation angle changing.

This study aimed to optimize the yield of wheat crop under rainfed Agriculture at Mosul zone in Iraq . this can be reached by the selection of proper time of seeding time which gives the best crop yield for rainfed Agriculture or by adding one supplementary irrigation of selected depth and time which gives the maximum yield or best economical return.In this study we generated data base using program (Aquacrop) for wheat yield with rainfall depth during the season for rainfall agriculture with rainfall depth +supplementary irrigation by using one irrigation during the season with depth (25,50,100)mm adding to one week of the season which is 23 week with initial water content between field capacity and wilting point with three date to begin the agriculture season the results showed that the optimal seeding time for the rainfed Agriculture is 15 December which gives 257.5 kg/ha yield and the next is 15 November 250.5 kg/ha and 15 January 89 kg/ha, For supplementary Agriculture the best time of the irrigation is the first week of the season with a depth change inversely with rain depth and the best seeding time is 15 November.

The aim of this research is to introduce guidelines and concepts to optimize the urban Design and planning for residential area and to contribute to the sustainable housing development in Kurdistan cities. The Housing Sector as one of the most important sectors in the city development has facing a lot of challenges in terms of sustainability due to the rapid population growth in cities of Iraqi Kurdistan. The city of Duhok as an example of other cities in the region has experienced dynamic urban growth in the last decades as a result of the unstable political and economic conditions in the Region. The local government has tried to cover housing shortage by many strategies such as plot distribution as well as supporting investors to provide housing units to meet people 's housing need. The main research objective is to evaluate the urban sustainability of the selected neighborhoods in the new developed area of Duhok city. The research used the principles of UN- Habitat for analyzing neighborhood sustainability by quantitative measurement of: efficient streets network, high density, mix use, social mix and limited land use specialization. The research outcomes indicate that there is an urgent need to direct the urban growth to more walkable mixed land use neighborhoods rather than car-oriented development by integrating the urban sustainability principles in the new housing projects to create healthier living environment for the residents.

This research deals with the experimental study of the effect of roughened the flood plain of symmetrical compound channel (having 18 cm main channel and 29 cm flood plain width from both sides) on the resistance of flow using different size of gravel roughness (D50=6.8 ,16.8, 24,47) mm, as well as the flood plain is smooth. Five discharges (34,27.8,19.35,12,7.87)L/sec were carried out for each case, The compound channel was divided to 3 sections perpendicular to the direction of flow and each of them divided to 7 sections , 4 in flood plain and 3 in main channel . Pitot static tube used for velocity measurements and point gage for water surfacelevel measurement as well as the temperature of water was measurement, From the measurements it can be concluded that the velocity over the flood plain was reduced clearly up to 40 – 70 % when the flood plain roughened by course roughness compare with that of smooth one , while the velocity in the main channel increased to satisfy the continuity equation . Empirical equations were developed to combine the resistance coefficient n with other variables include the flow and geometry characteristics

Hot Mix Asphalt (HMA), which are used in road's courses and flexible pavement structures, consisting of fine and coarse aggregates, filler, and binder(asphalt) ,mixed together in percent's according to a specific specifications.The main objective of this study is to investigate experimentally the effect of adding Steel Filing Aggregate (SFA) on the properties of Hot Mixtures Asphalt for surface layers. Steel filing Aggregate is a product of filing, drilling, and cutting of steel industry which, can be used as a partial replacement for fine aggregate in the creating Hot Asphalt Mixtures, for economical , environmental, and improvement purposes. The proposed mix designs specimens test of HMA for surface layer were prepared using : obtained Optimum Asphalt Content (OAC) (where the asphalt of penetration grade 40 was provided from Begi Oil Refinery, which was determined to be equaled 5.07 % (of the total weight mix) , ordinary portland cement as the mineral filler by 5 % (of the total weight of aggregates) and locally aggregates, and then tested according to Marshall test method (ASTM- D-1559&MS-2).Steel Filling Aggregates (SFA), which were passing through the sieve No.4 (4.75 mm) were added to the above HMA samples in three different percentages which were 5 % , 10 % and 20 % (of the total weight of mix) in order to evaluate their effects on some of the Marshall test properties of HMA .The experimental results and calculations for Marshall Tests on mix designs specimens test of HMA showed that adding SFA by above percentages on HMA, satisfy the requirements of the Iraqi General Specification for Roads & Bridges (SORB/2003) and has given significant improvement .The results also showed that 10% of SFA (of the total weight of mix) is the optimum percent .

Subsurface drip irrigation is an efficient irrigation method because it applies water directly to the crop root zone, but one of the disadvantages of this method is the positive pressure which is formed in the soil at dripopening especially in fine soils where the drip discharge is larger than the soil infiltration capacity which leads to decrease the discharge rate because the positive pressure will reduce the operation pressure of the drip. In this study, water was applied to ahole surface which filled with gravel to a needed depth,than distributed from the holebottom to all direction through the soil. Wetting front was observed during water supply and redistribution periods .Eighteen laboratory experiments for watching advance of wetting front at different times, by using cuboid-shaped container, dimensions (50*50*70) cm. two side of this container are plastic sheets, soil was compacted in the container to achieve bulk density. Two soils were used in the experiments, sandy loam with initial water content (3% and 6%), discharge (0.5, 1.04 and 2.14) L/hr, and silty clay with initial water content (5% and 8.5%), discharge (0.54 and 1.08) L/hr. For the both soils (5 and 10)cm radius of gravel container with 20cm depth was used, the container have holes from bottom and side at 5cm high to water exit. The volume of water applied was 4.5 L.The study presents equation to estimate fully shape of wetting pattern,by using dimensional analysis techniques, the effective variables on wetting front movement had been transfered to dimensionless groups, and by using the (SPSS)software a relationship was found between distance from center of hole to wetting front and time for all direction.

As the demands for more robot's complex tasks were increased, force and torque control had become necessary. When contact forces are present, the performance of the trajectory tracking controller is degraded. Impedance force / position controller is proposed in this paper. The impedance force at the tip is controlled by fuzzy PID controller. PID controller tuned by adaptive linear network is used for trajectory tracking. A combination of fuzzy PID controller and PID controller tuned by neural network is used to generate the required torque at the robot manipulator's joints. The Jacobian matrix is derived for planar 3-DOF to transform the forces into joints' torque. Simulations are presented for robot manipulator with force contact at the tip. The trajectory tracking is improved by using fuzzy PID controller for impedance force of the environment.

The relationship between inside and outside is considered as the principal one in architecture as it is one of its most important relationships in architecture’s history. Human had tended, from the very creation of being, to withhold a part of the outside space in order to form a special inside space of the building. This is done through containment as in making the cave as a refuge or through designation as in setting a space by using vertical or horizontal elements. This process is called “inside and outside” which might be the leading generated term of building construction. Human firstly and the architect secondly aim at finding, unceasingly, a relationship between interior and exterior spaces. And, as they do so; they manipulate the outer mass, inner space and mutual boundaries in-between through shaping them in a way yielding a relationship between both interior and exterior spaces; thus, to find similarity or dissimilarity between the shapes of the outer mass and the inner mass of the interior space. The present study attempts to study the similarity characteristic by studying its contrast as a characteristic of the relationship between interior and exterior to determine the differences between the architects' trends (Mies and Venturi) regarding to the relation of inside and outside. this relationship will be having a big role in determining the patterns of buildings, their trends, and intellectual and spatial affiliations.In order to achieve the objectives of the research, in the practical side, three (3) single residential houses were chosen for each architect, and After applying difference variables to the selected sample, throughout the study a vision had been put into words expressed in that: the difference between inside and outside is what is known as the (In between), Which is the resultant of, basically, pro forma purposes, which are adapted to perform particular functions later as in Mies Architecture, or any strict functional purposes as in Venturi Architecture.

The main goal of this work is to carry out a numerical modal analysis of a Quill shaft of turbo-generator unitaffiliate to Mosul gas turbine station, using a trail version of popular finite element analysis software SolidWorks. The main function of Quill shaft is to protect the turbo-generator unit against overloads due to electrical network faults. The high flexibility of this shaft makes it capable of absorbing high displacements of resonance phenomena. This analysis is essentially needed to study the effect of transient loads applied to Quill shaft of turbo-generator unit under severe loading conditions such as electric network disturbances. The first five values of critical frequencies and mode shapes of axial, bending, and torsional vibrations were studied and analyzed. Each mode has been isolated separately by applying a special type of boundary conditions (restraints) available in program. The three types of natural frequencies have been found and reported. It was observed that the fundamental values of each three types of natural frequencies are relatively high and out of the range of Quill shaft operating speed. Finally, it has been concluded from all analyses that Quill shaft under consideration is safe from the stand point of modal analysis. The results show that the Quill shaft is not running at any of each three types critical speeds. Therefore, the resonance phenomenon for all three types of vibrations can not be happened no matter how high the amount of transient load applied.

The laboratory tests carried out 12 tests to follow the advance of wetting front at appropriate times during the wetting and redistribution phases as a resulting of water application from a single linear trickle source or two linear trickle sources with a certain spacing to soil profile. These data are used to express with an estimating relationships for the wetting pattern produced by single linear trickle source and two linear trickle sources during wetting and redistribution phases. The study showed that there is a significant correspond between the wetting pattern of the measured and the estimated by the experimental equations. The wetting pattern increases with the decreasing of spacing between the two linear trickle sources, and this increase is regular along the wetting front or the surrounding of the wetting pattern, and this increase in the vertical direction of the wetting pattern is more in sandy loam soil than in silty clay soil and vice versa in the horizontal direction, when compare among the wetting patterns at the end of the wetting phase and the redistribution phase at a total time of 72 hours.