AL-Rafidain Engineering Journal (AREJ)

The stress analysis in the draw bar has been analyzed fully during the tillage operation in two different soil types. The study was done in a series of two stages : The first was done, in the Mechanical Engineering Department, University of Mosul in order to obtain the analysis of material to be used in this study, the mechanical and physical properties of the draw bar metals. The analysis of the soils to be used was obtained in the Geotechnical laboratory in the Civil Engineering dept. later the dimensional Analysis of the draw-bar was fixed, then the stress- analysis generated at varies points on the draw-bar was obtained using the finite element analysis using the ANSYS V5.4 program. during the application of the draw-bar in a similar condition. Special cases, were taken in consideration such as the stresses in X, Y co-ordinates, in addition to the principal stresses.During the second phase of this study, the stresses at a special locations were measured using a number of electrical resistance strain gauges fixed on the draw-bar while the Tractor was driven on two different soils at varies depth (30cm, 35cm, 40cm

This paper presents a new approach to real-time fault detection in power transmission systems using Fuzzy Logic (FL) based transmission line distance protection module. The proposed module uses samples of voltage and current signals to calculate line impedance, which used to construct an input-output data.Simulation studies are preformed and influence of changing system parameters such as fault resistance and fault location. Details of the design procedure and the results of performance studies with the proposed relay are given. Practical computer simulation program for monitoring the input and calculated values is built based on the Matlab 7.4- Real Time Simulink with National Instruments Data Acquisition System type (NI DAQ-6251). The results show that this approach can be used as an effective tool for high speed digital relaying, a correct detection is achieved in less than 10ms, results performance shows that the proposed algorithm is fast and accurate as compared with others used relays

The data of monthly discharge which are available for most of the rivers in the north of Iraq have a short recorded period ,which has a great influence in the design and planning of water resources systems , where this short recorded not contain a critical and extreme flows sample of the low flow sequences.Two stochastic models , bivariate \"Thomas & Fiering\" model and multi-side \"matalas\" model were used for generating time series for(100) years for the lower Zab and Diyala river at upstream of Dokan Dam and Derbendekhan Dam using the available recorded data for the period (1962-1997) .From application of different statistical tests (Kolmogrov–Smirnov), Chi-Square (X2), Root Mean Square Error (RMSE), Mean Absolute Error (MAE, Z), found that \"Matalas\" model is more performance than the bivariate model, \"Thomas & Fiering\" generate time series for both rivers, so it can be concluded that the \"Matalas\" model can be proposed to be used for generating the flow series for the different rivers in the northern Iraq

Most of infrared detectors used in various electrical equipments have wide spectral response and usually needs front filter to prevent visible light from passing to the detector. This research is intended to study and fabricate an indium doped silicon (n) (In-Si) structure to achieve a photo detector working as narrowband infrared detector. The SCAPS program was used as a simulation tool in order to achieve the optimum structure design. Then the (In-Si) infrared detector was fabricated using vacuum evaporation deposition technique. The fabricated photodiode shows a narrowband spectral response at 940 nm. The results of the simulated and practical samples are comparable which gives a simple and cheap method for obtaining narrowband infrared detector

The present study defines the research problem as a reformulation of a scientific aspect to study the relations between heritage and textural effects under the influence of the continuity. The studies discuss the relations of textural effects with heritage continuity. This research clarifies how strategically use the concept textural effects in architecture in achieving the communicated for architectural product depending heritage usage on different levels mentally. Formally and specially, research contains four axes: firstly, discusse the relation between textural effects and heritage continuity, and secondly, discusse the studies about textural effects, then differentiation the theoretical framework, thirdly, at last concluding the applying operations which represented by electing six main items of detailed theoretical field as the following. Firstly, the aims of textural effects, kind of textural effects, applications level of textural effects, Types depend on formal properties and Nature of the resources of textural effects, which limit the concept in architecture. In addition, the application of the items by electing four important projects in contemporary Iraqi architecture (as models) and crystallized the hypothesis, secondly. The application of the theoretical framework has revealed two patterns of utilization of textual effects in Iraqi Architecture, which attributed to designer architectural style. Similar results obtained from the theoretical framework had also been made by other observers, all of these points paid special attention about this effect in general. It is relation with heritage continuity in specific, which clarifies the utilization of it in two types. The revelations demonstrate the validity of the assumptions made in the development of the theoretical framework. Finally, this paper lays down a set of guidelines for other architects who wish to apply the type of Iraqi Architect to produce an Iraqi Architecture with textural effects under influence of continuity.

This paper presents the design of Delta-Sigma ΣΔ based fractional N PLL frequency synthesizer for GSM mobile systems. The loop filter is one of main element in fractional-N ΣΔ synthesizer because it shapes the noise spectrum of quantization error and reduce the spurious level in the pass band of PLL. The effect of loop filter order is studied and it is shown that by increasing the order of the loop filter, the phase noise performance will be improved, although this requires careful design consideration, as the PLL is prone instability. It's shown that the 3rd order loop filter and 3rd order ΣΔ modulator gives the best performance with reducing phase noise (13dBc/Hz ) and spurious noise (44dBc) of the output signa

In this paper a new type of indium doped SnO2/SiO2/(textured) n-Si solar cell were prepared by vacuum evaporation source.. The SnO2 layer is simultaneously an antireflection coating and a transparent upper contract. The interfacial layer plays an important role in determining the short circuit current, open circuit voltage, fill factor and efficiency of the cell. In this paper, the effects of interfacial oxide layer thickness, SnO2 layer thickness, indium layer thickness were studied. The indium doped SnO2 layer reduces the cell series resistance and hence increase the cell output power, the performance parameters of the fabricated solar cell were as follows: an Voc of 0.646 V, Isc of 29.6 mA cm-2, a fill factor of 0.7 and a conversion efficiency of 13.38 at an AM 1.0 irradiance.

In this paper, the effect of the band gap grading of the absorber layer Copper Indium Gallium Selenide (CIGS), which is a compound semiconductor, on the performance of the solar cell has been studied. CIGS has a tuneable band gap and it varied with the composition of the semiconductor. This study has been accomplished using the computer simulation program SCAPS-1D. The program was developed to study the photonic devices especially CIGS and CdTe thin film solar cells. The effect of the grading shape (Front, Back and Double Grading) on the performance of the cell has been studied so as to improve the efficiency of the cell

In this paper, the predictive schemes of reducing call termination during handoff in Code Division Multiple Access (CDMA) system using position location in the required handoff area with minimum false handoff, where the mobile station (MSs) are located randomly in the cell and each MS has call duration, speed and direction, the speeds and directions of the MSs are varied. The signals between the MSs and Base Stations (BSs) are dealt with by using position estimation method using time difference of arrival (TDQA) of the signals, estimation of the variable MS location, knowing the speed and the direction leading to a neighboring cell. The results obtained comply with Federal Communication Commission (FCC) which is internationally adopted. Also, the blocking probabilities for handoff and for new calls using Predictive Channel Reservation (PCR) scheme and Guard Channel (GC) are studied. The results show that predictive scheme reduces the blocking probability depending on the number of reserved channels. MATLAB software (version 7.6) was used to perform the simulation programs

Different wireless networks satisfy different users. The proposition of a single unified handoff approach is to offer the end user the quality of service (QoS) required. In this paper, vertical handoff between wireless fidelity (Wifi) and Universal Mobile Telecommunication System (UMTS) networks is investigated using MATLAB program 7.4 in order to maintain constant throughput during handoff. Three different propagation models are used. The variation of throughput with distance, received signal strength with distance and the effect of different speeds in macro and microcells are dealt with.

This work demonstrates the application of Artificial Immunized System (AIS) in designing on-line the parameters of the Linear Quadratic Regulator (LQR) for SISO plant. The AIS is used in creating the adaptive critics which represent the matrix parameters in the solution of the Riccati equation of the LQR. It is found that the AIS possess promising features to deal on-line with the plant parameter variations and reflect acceptable regulating and tracking characteristics.

In this paper, a software model for a Command and Control system is implemented on personal computer. This model can also be used for navigation, or Air Traffic Control (ATC) systems. The hardware required for implementation of this system is also described in this paper. The system assumed to have a fixed position detection source such as the surface search radar. The principle of Track-While-Scan (TWS) that combines the automatic detection of targets and the automatic multi target tracking is used.The Simplified Alpha-Beta-Gamma (--) digital filter is used to perform the algorithm of the automatic tracking. The model main program and all necessary routines are written in C++ language. Successful tests for the implementation of this system are achieved.

This paper presents a design methodology of a dual-input single-output fuzzy logic controller where synthesizing the classical three stages, fuzzification, inference engine, and defuzzification, are replaced by the outcome control surface obtained from these stages which is treated as a tow dimensional table called fuzzy control table FCT. With this proposed approach, (8x8), (16x16), (32x32), and (64x64) FCTs were investigated each having 64, 256, 1024, and 2048 values respectively. To make this system adaptable to different operating states a supervisor fuzzy controller is designed to continuously adjust, on line, the output factor of the basic fuzzy controller based on the error and change in error signals. The proposed architecture is implemented in XC3S200 FPGA, Spartan-3 starter kit to control the position of a D.C. servo motor with unknown parameters in real time

:Image compression is an important topic in commercial, industrial, and academic applications. Whether it be in commercial photography, industrial imaging, or video, digital pixel information can comprise considerably large amounts of data. Management of such data can involve significant overhead in computational complexity, storage, and time processing. This paper presents the implementation of a Modified JPEG CODEC algorithm for color images based on inter pixel redundancy. The modification uses the similarity of the adjacent pixels in blocks to omit complex calculation which AC components require in 2D-DCT unit. It applies quantize operation to one element instead of 64 coefficients and eliminates the zigzag unit. Finally , the entropy phase will process a smaller amount of data. In the decoder side the Laplacian parameter is estimated adding to a reduction in the accounts of blocks that have same neighbors pixels. The extensive experimental results demonstrate that the proposed approach can achieve best image quality. The Simulation results show that the Modified JPEG(MJPEG) algorithm can process a 512 X 512 color image in a reduced processing time ( more than 40%) compared to the original algorithm and by more resilience with higher compression ratio

The heat pipe is a very effective device in heat transport, therefore it is used in many industrial applications especially in cooling systems. In the present experimental work, wickless heat pipe(thermosyphon)is designed and constructed from a copper tube of inside and outside diameters (13.5) and (15.5)mm respectively with total length of (600)mm divided into three sections evaporator; adiabatic section and a finned air cooled condenser simulating the actual applications in practice of this device. Pure water, pure hydrocarbon fluid (acetone) and mixtures of the two fluids at different ratios by weight were used as working fluid to investigate the effect of a working fluid type and mixture ratio on the performance of the device. Results show that using pure fluid is more effective than using mixture. Comparison between results of the present work and a theoretical correlation shows a good agreement especially when using pure fluid

Exhaust gases of gas turbine generators contain a significant amount of thermal energy which can be recovered externally or internally to the cycle itself. The most effective technology option for external heat recovery is the combined gas-steam power plant. The internal recovery conventional solutions are based on thermodynamic regeneration and steam injection.In this study a thermal analysis and performance evaluation has been carried out to investigate the benefit of applying combined cycle power plant on Beijee simple gas turbine generators. Beijee gas turbine generator has been modeled and simulated to observe its performance including power output , thermal efficiency , specific fuel consumption and exhaust gas temperature as it is operating for the time being. Thereafter, simulation was carried out to investigate the performance of the suggested unit when a combined cycle power plant is used.Results show that a significant improvement in the performance of Beigee gas turbine unit when a combined cycle mode is applied. For example the power output is found to be increased nearly by 49.3%, the thermal efficiency increased nearly by 20% and the specific fuel consumption decreased nearly by 10%.

This paper represents an experimental investigation to evaluate the effect of magnetic field on exhaust emissions and engine performance of four-stroke, single piston spark-ignition engine working with (10% vol.)Ethanol-Gasoline blends. Carbon monoxide CO, carbon dioxide CO2 and unburned hydrocarbon HC are examined during running of the engine with and without the presence of magnetic coils. The engine performance parameters (brake power, brake specific fuel consumption and brake thermal efficiency) are investigated too .Two magnetic coils with different intensities (1000 and 2000 Gauss) were used . The magnetic coil is placed on the line of fuel supply before the carburetor. All tests were conducted at a wide open throttle (WOT) , compression ratio 10:1 , speed of 2000 rpm and ignition timing ( between 50 and 300 BTDC ) . Results show a significant reduction in exhaust gas emissions when applying the magnetic field. A maximum reduction of 68.8 % of CO, 15 % of CO2 and 42.5 % of HC are observed when using 2000 Gauss magnetic coil. Moreover, it was noticed that all engine-affecting parameters were improved. Running the engine with 2000 Gauss and 10 vol.% ethanol-gasoline blends shows better results ( concerning pollution emissions and brake thermal power ) than 1000 Gauss magnetic coil .

In this study, four multi-story building parking garages located within the CBD area of Dohuk city had investigated for different characteristics of parking behavior for user. Parking accumulation, volume, walking distance to destination point, turnover, duration, and mode of travel were investigated within the duration from 9:30 a.m. up to 4:30 p.m. Trip purpose were introduced within a special interview form used to collect the necessary parking data from each facility users. Figures, and tables presented out of this study demonstrate that the amount of spaces provided on the three parking facilities were about 717 spaces with peak demand already taking place at mid-noon. Average walking distance concluded was 155m and four hours as an average parker duration. Average turnover obtained out of the data analysis was 1.09 vehicles /one space.