Al-Rafidain Engineering Journal (AREJ)

The physical environment of schools is an important factor affecting students' learning. Appropriate educational institutions must be provided. It meets the various reasons for change, and the educational environment must enjoydurability with its spaces and ability to adapt to new jobs and activities. Reducing the surface area of ​​the structure, the research problem was that the available studies did not accurately determine the role of some design characteristics (Proximity characteristic) in achieving compact entity (as an indicator of functional Durability), and the possibility of applying these characteristics to local primary school models. The aim of the research is to (determine the role of that feature and the procedures available to the designer in absorbing the change in the buildings of the elected primary schools), and conduct a special practical experiment in addition to a generative program that works with algorithms (Dynamo); to ensure the impartiality of the results, the research found that the convergence property has a prominent role in maintaining On the compactness entity of the schools, and therefore the convergence property can be relied on in the architectural programming stage for the ease and accuracy of measuring that feature at that stage of the design process.

The use of Carbon Fiber Reinforced Polymers CFRP in strengthening and rehabilitating structural members is one of the modern techniques which proved to be effective in different civil engineering applications. This review aims to provide the researchers and construction specialists with a detailed description on the practical application of External or Internal  Carbon Fiber Reinforced Polymers in strengthening and rehabilitating concrete, steel, and composite members in flexure and shear.

This review evaluates industrial waste: its definition, components and types, and then its impact on the soil.  the remarkable ‎development in industry in recent times and its progression forward led to more secondary products, which at present ‎constitute one of the most important problems facing the scientist. The researchers discuss the extent to which they can be ‎used in soil stabilization by reviewing most of the research and studies on industrial waste and soil. In addition, the ‎advantages and disadvantages of using industrial waste in treating soil problems at the lowest possible cost without ‎resorting to other alternatives. This paper also presents the role of society in reducing its environmental damage by ‎reviewing researches and studies on recyclable materials and the most applicable at present by the industry, which is a ‎suitable idea to incorporate the best-recycled materials in the construction of roads and engineering facilities. These steps ‎came after taking the processes of recycling and reusing industrial waste in many forms and methods, and according to the ‎nature and type of waste and the purpose of its reuse, in addition to the state and nature of the material with which these ‎wastes are used.‎

This study deals with the structural evaluation and compression is made between the methods of calculating the damage index of a two-dimensional reinforced concrete structure. A three bay, ten storys frame was designed based on the specifications of the American Concrete Institute (ACI 318-19), the structure was analyzed by non-linear dynamic analysis method by exposing the frame to three different types of earthquakes using (ETABS Version 19.0.0) program. Several methods proposed by researchers were used for calculating the total damage indices of the structure, another method was suggested in the present work, there was convergence in the values calculated on the basis of the composite methods of physical and engineering variables compared with the methods that depend on engineering variables only, such as ductility or displacement. The damage indices based on physical variables only, such as the hysterical dissipated energy, was considered ineffective in representing the real damage, especially in the case of medium and large damages, and it is advisable to adopt more than one method to ensure the safety of the structure and not to rely on one method determined by a few variables in order to express the exact and actual damage in all aspects.

Electrical power systems around the world are currently operating near the limits of security and stability design, due to economic considerations and high rates of demand for electrical energy. During their operation, these systems are exposed to various types of disturbances, which in severe cases lead to their complete loss and complete shutdown. Dynamic security assessment is one of the most important tools used in evaluating the performance of electrical power systems after these disturbances occur. The traditional mathematical methods for evaluating dynamic security require complex computations and computational time so that they are not suitable for evaluating dynamic security in real time. To address these challenges, this research was conducted to provide new tools based on advanced techniques of artificial intelligence techniques capable of building a classifier to evaluate its dynamic behavior in real time. The research methodology in this study relied on the use of artificial intelligence techniques, including back propagation artificial neural network, decision tree algorithms (J48) and logistic model tree (LMT). Which was applied to the emergency database of the electrical power system (IEEE 14 Bus) test model after applying the most common types of electrical disturbances. The results of the artificial neural network technology showed high classification accuracy (98.958%) and a lower error rate compared to the decision tree (J48) and (LMT) algorithms. The results of this research are very important to improve the accuracy of the results of the dynamic security assessment classifier for the electrical power system, which makes it easier for the network operator to take appropriate protective measures in the moment of disturbances in the network.

The Iraqi electrical system suffers from an increased electrical load for the available generation, which leads to the separation of a large number of consumers, especially during the peak load period. The water heating load represents a great value, so reducing water heating consumption can reduce the cut-off times. Solar water heaters possess many benefits. Therefore, they are used in many countries in the world today. The climate of Iraq is mostly hot and sunny. This makes using a solar water heater is convenient for consumers, especially in urban areas. For studying the use of solar water heaters in the residential sector, three consumers were selected in Mosul city in northern Iraq. Each consumer differs from the others by the value of their consumption of electrical energy (high, medium, and low). Electricity tariffs for the residential sector in Iraq vary, depending on consumption.  The information for the three consumers was obtained from a previous questionnaire. In addition to obtaining their needs for hot water, the results of using solar water heaters on the roofs of the three houses of consumers showed a decrease in electricity consumption and a noticeable saving in the electricity bill. The payback period of the solar water heater system was calculated for each consumer.  Reducing consumption reduces the gap between generation and load, resulting in reduced programmed shedding times for consumers. For these benefits and environmental features, it is necessary to generalize the use of solar water heaters in the residential sector in Iraq.

The spread of distributed power stations, especially small power stations that use renewable energy sources, as well as the connection of a large number of distributed power stations to the network led to the necessity of making some changes in the electrical distribution system. Therefore, the Solid State Transformer (SST) has recently emerged as a suitable alternative to the traditional transformer. SST is characterized by its small size and weight, and   as the possibility of controlling the direction and amount of power flow, improving the quality of power, the possibility of controlling voltage, compensating reactive power and other advantages that are not available in the traditional transformer that can be of paramount importance to the development of the power system. This paper reviews solid state transformers in terms of their components, working method, mathematical analysis, design steps, and control process. ANSYS Maxwell 3D software was used to design and model the high frequency isolation transformer and a working model of the core-type high frequency isolation transformer was presented. It was found through the results of the study and analysis of the solid-state transformer that it would be a suitable alternative to the traditional transformer that works at high frequencies.

One of the problems that face the use of XLPE insulators is the appearance of defects. These defects appear during the manufacturing processes of the insulator, and one of these defects is air cavities or voids. The defects presence within the insulators of high voltage cables affects the distribution of the electric field within the cable layers. The distortion of the electric field due to the presence of air cavities is the main reason for the treeing appearance inside the insulator, which eventually leads to the emergence of partial discharges that reduce the life of the cable. In this study, the effect of the presence of an air cavity inside an XLPE insulator was studied by changing the dimensions of the cavity, that is, changing the ratio of the dimensions of the cavity parallel to the electric field and vertical to it and the effect of this on the value of the electric field in the center of the cavity. It was noted that the electric field in the cavity is higher than in the external electric field. The increase in the field in the cavity center does not depend on the cavity size, but rather on the ratio of the cavity dimensions parallel to the electric field to the vertical to it. The electric field enhancement factor was calculated based on the simulation results, which showed a reasonable agreement with the theoretical values.

This paper presents a method to control on single real-frequency transmission zeros (TZs) position in the reject band for third-order waveguide band pass filter (BPF). The external couplings are achieved by using a coaxial probes while the internal couplings are achieved by using short-circuit metallic posts. The TZs appear are generated by forming a triplet, i.e., multipath cancellation between non-adjacent resonators. The dimensions of the metal post between non-adjacent resonators are adjusted to control the position of TZs in the rejection band. A third order waveguide generalized Chebyshev BPF is simulated with HFSS at a center frequency of 28 GHz to validate the design method. The simulated insertion loss is 0.05 dB and the bandwidth (BW) is 500MHz. The simulation demonstrates the compatibility of the presented filtering structure with 5G applications.

Power generation is normally produced at constant frequencies of 50 Hz or 60 Hz and the generators E.M.F can be considered practically sinusoidal. However, when a source of sinusoidal voltage is applied to a nonlinear device or load, the resulting current is not perfectly sinusoidal. Due to non-linear loads, distortions are produced in the sinusoidal waveform so filters are used to minimize these distortions. This paper aims to build a simulation model of a nine-bus ring system to evaluate characteristics of harmonics in different cases of study using electrical transient and analysis program (ETAP), which is considered one of the best tools to study harmonics in the power system, thus, the harmonic distortion is analyzed in ETAP. To generate harmonic distortion in the power network, a general load is modeled as a source of harmonics. A harmonic load flow analysis was carried out in order to determine the impact of harmonic current on a power network, and the THD% of all types of harmonic models on all the buses was checked and the typical IEEE model that has the highest THD% was chosen and compared with the model that contains low THD indices (one of the best models of IEEE manufacturer).

Because of the fast advancement in the creation of power electronics equipment such as automatic Machines, adjustable speed drives, personal computers and other non-linear loads which are the main sources of harmonics. Due to the presence of these nonlinear loads, it is necessary to reduce the level of harmonics created in the power networks. Hence, harmonic analysis of distribution networks is important. The analysis of power systems is an important part of power system engineering. Any electrical utility company's principal goal is to provide the best quality of power. The power system harmonics is one of the major reasons of poor power quality. Harmonics and harmonic analysis must be investigated in filters in order to minimize harmonic current and voltage. This paper aims to build a simulation model of nine bus ring system to evaluate characteristics of harmonics in different cases of study using Electrical Transient and Analysis Program (ETAP). Using ETAP harmonic distortion is analyzed and mitigation techniques are used represented bysingle tuned filters which should be installed for worst case and the best-case condition. And the simulation results of ETAP shows that some of THDv,i%  results are within the limit value as per IEEE 519 -1992 standard.

Rotary friction welding is a solid-state technique for combining two materials together by using the heat energy generated by the friction at the interface region between them with help of an external axial force. The main goals of this work-study were, to look to the researches works that studied RFW, to understand their thermal models of the RFW process, see mathematical, simulation models and the assumptions taken into account, and compare with the experimental results of their works if exist. The results we obtained from previous researches were as follows: The rise in the temperature of materials during the welding process leads to a change in their properties, so the heat generated during the process is not constant. The heat generated is divided into two parts, heat generated by rotating and sliding friction, and heat generated during plastic deformation. With the temperature rising, the yield stress reduces until it became less than flow stress, and then the plastic deformation starts. The heat transfer throw the solid work pieces is analyzed by Fourier heat conduction law. Compared the simulation results with the experimental results of the researches we can say that, the welding process can be represented numerically through software programs.

In this research study, numerical modeling was present to describe the effect of key processing parameters of continuous drive rotary friction welding (CDRFW) on thermal characteristics of similar aluminum alloy joint and dissimilar aluminum alloy /low carbon mild steel joint, using (ANSYS). A mathematical model was made to describe the heat generated in the workpiece due to the frictional force and the plastic deformation, and the heat transfer throw workpiece was described based on the Fourier law of heat conduction. The parameters were: Frictional pressure (P₁), forging pressure (P₂), frictional time (t₁), forging time (t₂), and rotational speed (N). A range of welding parameters was taken. The results show that with increases in welding parameters, the welding temperature at the interface region and the axial shortening will increase for both similar and dissimilar joints. For similar and dissimilar joints, frictional pressure and rotational speed have the most effect on maximum temperature at the interface, frictional time affects less while forging pressure and forging time have no effect on maximum temperature at the interface. For similar and dissimilar joints the most influential parameter on axial shortening was frictional pressure, with little effect for forging time.

In this paper, we conducted an experimental study to study the improvement of the coefficient of performance of a hybrid solar air conditioner and compare it with the performance of a conventional air conditioner. In addition to studying the rate of electrical energy savings for the hybrid system. The study included the study of the factors and variables affecting the performance of the hybrid solar air conditioner during three continuous months (June, July, and August). The hybrid solar air conditioner consisted of a conventional R-410a split air conditioner with cooling capacity (12,000 BTU) and a variable speed compressor integrated with a solar collector. The solar collector consists of a flat solar panel combined with a hot water storage tank. Inside the tank there is a copper coil heat exchanger, inside which the refrigerant leaving the compressor of the hybrid solar air conditioner passes. Two solenoid valves were installed to control the flow direction of the refrigerant leaving the compressor either to the solar heat exchanger and then to the condenser or directly to the condenser. The results showed that the highest improvement in the coefficient of performance of the hybrid solar air conditioner without refrigerant flow direction control - first case, and hybrid solar air conditioner with refrigerant flow direction control - second case are (12.2% and 16.3%) respectively compared to a conventional air conditioner, and that the highest rate of electrical energy savings for the solar hybrid air conditioner - the first and second cases are (15.9% and 18.7%) respectively compared to a conventional air conditioner.

In-situ composites are a class of composite materials in which the reinforcing phases (such as Al₂O₃, TiB₂,TiC, etc.) are generated within the matrix material by some chemical reaction during the composite processing.  This research paper compares the microstructure, mechanical and tribological properties of the resulting cast in-situ Al(Mg,Mn)-Al₂O₃(MnO₂) and Al(Mg,Ti)-Al₂O₃(TiO₂) composites. It is generally observed that intermetallic phase Mn(Al_1-x Fe_x)₆ in the cast in-situ Al(Mg,Mn)-Al₂O₃(MnO₂) composite is relatively finer in size and is sometimes blocky in type compared to Ti(Al_1-x Fe_x)₃ formed in cast in-situ Al(Mg,Ti)-Al₂O₃(TiO₂) composite. This has been attributed to a difference in heterogeneous nucleation behavior of the alumina substrates during the phases of intermetallic formation. Superior mechanical properties, represented by ultimate tensile stress, yield stress and percentage elongation, are obtained in the cast in-situ Al(Mg,Mn)-Al₂O₃(MnO₂) composite and compared to those obtained in cast in-situ Al(Mg,Ti)-Al₂O₃(TiO₂) composite.It is observed that the wear rate in cast in-situ Al(Mg,Mn)-Al₂O₃(MnO₂) composite is considerably lower compared to that of the cast in-situ Al(Mg,Ti)-Al₂O₃(TiO₂) composite, particularly at higher normal load of 39.2 N, in spite of a relatively higher porosity content and slightly lower hardness in cast in-situ Al(Mg,Mn)-Al₂O₃(MnO₂) composite.

This study aims to model the wetting patterns of the homogeneous and stratified soil profile, and to derive an equation to estimate the discharge rate during the application time. The study included conducting 8 experiments to monitor the progress of the wetting patterns over time in a homogeneous and stratified soil profile. Two types of soils were used (silty clay loam and sandy Loam). The emitter was installed at a depth of 45 cm below the soil surface, and soil profiles were prepared in two different sequences and the location of the interface between the soils was changed (at the dripper, 10 cm below the dripper, 10 cm above the dripper). The results showed that there is a good agreement between the measured and estimated advancement distances, where the determination coefficient R2 ranges between 0.826 to 0.989. Moreover, the results showed that the emitter discharge gradually decreases and continues to decline with the continuation of the operating time until it reaches an almost constant value. This reduction in emitter discharge increases by increasing the clay content, soil bulk density, emitter depth, and initial moisture content. The results also showed that the largest wetting front advance distance in the horizontal and vertical directions was in the sandy loam soil profiles, while it was the least valued in the silty clay loam profiles for the same operating time. The interface between the layers also helped in the horizontal and vertical diffusion, especially when the silty clay loam soil was placed below the dripper, which helped in the spreading of water in the horizontal and vertical direction upwards.

The meander rivers are notice condition in nature more the existing river in nature. In which the river continues process in scour and deposition sediment transport normally the scour in the outer side of a river bank and the deposition will be in the lift bank. Due to centrifugal and secondary currents for the flow. To control the movement of the sediment to overcome of the scour and deposition the spur dikes used as a one way to protect the river bank and to control of the sediment movement. In this research we locate spur dike in the straight portion of laboratory channel before entering the bend or meander to see what is the effects of this spur dike. The spur was fixed in different location in this straight portion at left, right and both side in different angle (30°, 90°,135°, 150°) with different discharge (24.096, 27.477, 31.016, 34.71) l/sec. The results shown that the spur dikes at the left side are  Reduces erosion and deposition Compared without spur dike at the section (1.9, 2.9, 3.9, 6.1)m, and the large erosion and deposition was when we put spur dikes at both side of channel with angle 90°.  

Flow becomes more complicated in meandering and natural channel which leads the researchers to focus on the observations of natural and laboratory channels to study the characteristics and hydraulics flow in meandering channel. Three cases for installing impermeable and permeable spur dike with 30o in the entrance of meandering channel (left side, right side and both sides of channel) are used in this study using four levels of discharge (24.096, 27.477, 31.016, 34.71) l/sec for each case. The study concluded that the permeable spur dike reduced the amount of erosion and deposition in the meandering channel and maximum deposition (18.2cm) occurred in the case of impermeable spur dike on both side of channel at 2.5m from the beginning of the curvature of meandering channel and at biggest discharge (34.71) l/sec. The results of experiments showed that the minimum erosion (9cm) occurred in the case of permeable spur dike on right side of channel at 0.3m from the beginning of the curvature of meandering channel and at biggest discharge (34.71) l/sec where the impermeable spur dike has reduced the maximum depth of engraving by (10)%.

Physical and Numerical models have been used to maximize the dissipation of flow energy of a sipllway, and to guarantee the occurring of hydraulic jump in the stilling basin in shorter length, and to find the right model to simulate turbulent flow properties using the techniques of Computational Fluid Dynamics (CFD). 5 models have been tested which they had different rows of chute blocks. For each, 6 slopes of chute were examined, 1:0.8, 1:1.0, 1:1.2, 1:1.4, 1:1.6, 1:1.8, with 10 cm of tail water. Physical models were emplemnted to represent a sucssecfully models that compared with the theoretical model in a slope 1:1.2 for chute. Using the RNG & K-є as a turbulent theoretical model and a non uniform distribution of the mesh led to sucssesfully simulating the stream lines, velosities and shape of hydraulic jumps and Froude numbers. Using four rows of choute blocks at the end of the chute near the edge is the best design to dissipate the energy, which was 61.9%, and for spillway slope of 1:0.8, while the percentage of energy dissipation that depending reducing the distance of the roller jump and reducing the distance of the supercritical flow was laid between (17.8, 94.8)%, respectively, when the spillway slope is 1:1.0.

The research included studying the effect of each of the size of catch  cans and the spacing between them on the calculation of water distribution uniformity coefficient and with different spacing between sprinklers and for several sprinklers heads, The research included conducting 10 tests, each test of a different sprinkler head, which included finding three patterns for water distribution along a ray, each representing a radius of a circle of wetness at its center, using different sizes of catch cans, where for each ray there is a different diameter of catch cans. And 480 patterns were found to distribute the field sprinkler irrigation water to cover the sizes and spacing of the catch cans and the spacing between the sprinklers and the different sprinkler heads. The research showed that when  the water distribution pattern is symmetric around the sprinkler and there is no wind; there is no effect of the diameter of the catch cans on each of the water distribution pattern along the ray, which represents the radius of the wetness circle, its center is the sprinkler, the uniformity coefficient UC and the distribution uniformity coefficient DU. And both the distribution uniformity coefficient UC and the distribution uniformity coefficient DU increases with the increase of the spacing between the catch cans. Two equations were also devised to express the uniformity coefficient UC and the distribution uniformity coefficient DU at the spacing of catch cans (1 m * 1 m) as a function of each of them at greater spacing between catch cans..

To find out mechanism scour downstream weirs and study  effect changing  ratio width of keys  Wi/W_o , length of Apron solid and studying effect of changing the lateral length B on depth and length of the maximum scour by passing different discharge and using homogeneous  soil. A laboratory study was conducted to measure depth of scour  downstream   piano key weir type C and to show effect height weir, ratio width of keys and length of apron solid. Three heights of weir (25,30,35) cm , three ratios of width keys (1,1.25,1.5) and two distances were used  For apron solid (90,120) by passing four different discharges (15, 22, 29, 36)) l/s in experiments, where number of models used nine models, on which (72) experiments were conducted. The depth of scour  for all experiments that by reducing height weir , maintaining ratio width of the keys and discharge, scour  decreases for all experiments. The results also showed that by increasing length of apron solid by 33.33%, the scour depth will be decreased by a rate ranging between (2.17-28.75)%. and that by increasing the percentage of the width keys from ratio (1) ) to ratio (1.5) scour depth decreases by a rate ranging between (13.04-47.38%) for all experiments, decreasing height of weirs from 35 cm to 25 cm, the percentage decrease scour depth ranged (20-40.2)%. To arrive at a positional equation in terms of variables and a coefficient of determination of R² = 0.958 .

The current study included 12 laboratory experiments on a soil model stacked inside a container with a metal structure with two transparent faces, in order to monitor the movement of the wetness front inside the soil with time; its dimensions are 50 cm, 50 cm, and 70 cm. The polka dot is fixed in one of its corners, sandwiched between the two transparent faces, to observe the quarter of the wet bulb formed in three dimensions. Experiments were carried out on two types of soil, mixture and clay, where the dripper works with two charges 130 cm and 105 cm above the dripper level. The processing is done in two ways: continuous (cycle ratio 1) and intermittent with a ratio of 1/2 cycle and a processing time of two hours for each cycle and a ratio of 1/3 cycle with a processing time of 1 hour for each cycle. The data that were monitored during the experiment period are the rate of drip discharge with time and the limits of the wetting bulb with time as well. Auto-CAD program was used for drawing the shapes of the progression of the wetness front with time from the obtained images, and these shapes were used for finding the distance of progress in the horizontal, vertical, upward and vertical downward directions for all twelve experiments. Microsoft-Excel program was used to estimate the distance of progress in the three directions in terms of the factors affecting them and with a coefficient of determination (0.902) for horizontal progression, (0.92) for vertical upward progress and (0.88) for vertical downward progress. The results showed that the droplet discharge changes with time by an exponential function, and that the rate of discharge increases at the beginning of each cycle and then returns to its true level after a period. The study also showed that the volume of wet soil because of processing a certain volume of water decreases as the cycle rate decreases.

The research aims to study the characteristics of each of the infiltration depth, wetting front depth and the initial moisture of the soil in the case intermittent ponding depths using successive cycles for distribution and redistribution patterns with different durations. Six laboratory experiments were conducted for cylindrical infiltration under intermittent ponding included four distribution cycles, each cycle includes distribution pattern with continuous ponding and redistribution pattern  with intermittent ponding or without ponding. Also, one cylindrical infiltration under continues ponding was done for comparison purposes.  Empirical relations were derived to express the wetting front depth, the initial moisture of soil, and the accumulative infiltration depth and infiltration rate. The results show that the average initial moisture increase during the successive distribution cycles , then seemed to be constant. The results also indicate that the infiltration depth with intermittent application is more than that of continuous application at the same application time and the difference increased as ON/OFF ratio decreased. Further, the results show that the infiltration rate with continues ponding is approximately equal to infiltration rate with intermittent ponding at the end of redistribution pattern for successive cycles.   

The precise position control of a DC servo motor is a major concern in today's control theory. This work presents position following and forecast of DC servo engine utilizing an alternate control technique. Control technique is required to limit and diminish the consistent state error. A model predictive controller MPC is utilized to plan and actualize these prerequisites. Two sorts of controlling techniques are presented in this task. The Active Set Method (ASM), the inside point technique (IIP), and have been utilized as controlling strategies. This work distinguishes and depicts the plan decisions identified with a two sorts of controllers and judicious regulator for a DC servo motor. Execution of these regulators has been confirmed through reproduction utilizing MATLAB/SIMULINK programming. As indicated by the recreation results the Comparisons among ASM, IIP. The tuning strategy was increasingly proficient in improving the progression reaction attributes, for example, decreasing the rise time, settling time and most prominent overshoot in Position control of DC servo motor.