Journal of Engineering and Sustainable Development (JEASD)

Inverters are widely used in many applications & the object of using the inverter is produce ac voltage with controllable magnitude & frequency. But the inverters where found in both the industrial motor drive industry & in the emerging distributed power generation industry, since these were essentially the only source of three phase inverters in the power range of interest. There are many types of multilevel inverters (MLI), but the cascaded multilevel inverter (CMLI) is most the favorite one for industrial applications. The three phase (CMLI) is used with optimization technique to suppress specific low-order harmonics or minimize total harmonic content & then improvement system efficiency .This technique of pulse width modulation (PWM) based on Walsh function harmonic elimination method. In this technique the harmonic amplitude of the inverter output voltage can be expressed as functions of switching angles. Thus, the switching angles are optimized by solving linear algebraic equations instead of solving nonlinear transcendental equations. This technique is suitable for higher level of three phase cascade multilevel inverter (CMLI) where other existing methods fail to compute the switching angles due to more computational burden. For the number of output voltage levels where multiple solutions exist, the solutions where produce least total harmonic distortion (THD) in the output voltage is chosen. As compared with previous work, the decrease in the THD can be reduced to (3%) in case of the proposed technique. In this paper, significant decrease in THD is obtained by solving linear algebraic equations for switching angles....

In this study, a correlation between an approximate analysis of beam vibration problem and experimental measurements of vibration property was achieved in an attempt to develop a simple and reliable experimental method for determining the elastic constant of materials as a non-destructive test. The analytical solution was based on Euler and Rayleigh beam models with simply supported boundary conditions, and the experimental work was based on Dunkerly's approach. Development of an existing test setup was done to be more suitable for beam specimens of composite materials. The present experimental measurements of the elastic constants were compared with published results and it is found that the proposed experimental work is provided acceptable and reliable measurements. The comparisons indicate errors in the measurements that are ranging between (3.1-12.7) % based on the Euler model and (0.87-4.6) % based on the Rayleigh model. Finally, a numerical solution to the problem based on the feedback of the present experimental results was developed using a computer package program called ANSYS. The numerical results reflected that the proposed experimental scheme is a simple, reliable, and accurate one.

Natural convection heat transfer with two-dimensional in an annular enclo¬sure is examined numerically for Rayleigh numbers rating from 103 to 105and for aspect ratios 1,2,3. The outer wall is heated using a linear temperature while the inner wall of the annular enclosure was cold, the top and bottom ends was adiabatic.The stream function– formulation was used in the mathematical model of the case under discussion where the differential equations were converted to algebraic equations using finite differences method. The numerical solution ability to calculate stream function, temperature and Nusselt number during the computational domain. The numerical results showed that the main process of heat transfer is conduction for Rayleigh number less than Ra≤103, and convection for Rayleigh number greater than Ra>103. Average Nusselt number is increased with aspect ratio increasing for Ra ranging with (103-105) because increasing of heat transfer area. To ensure the reliability of the numerical solution a comparison of the current results with that of previous research, shows a good agreement between the results and this is confirms the validity and reliability of the current model.Key words: natural convection, annular, enclosure, numerical, laminar.

This work-study design system detection to detect magnetic mine or magnetic material which is hidden in any place under the car or vehicle using hall effect sensors. Hall effect sensors could be entirely integrated on a single silicon chip several sensors might be used in a modern device as switches, latches, or linear sensors. A hall effect sensor is a small sheet of semiconductor material represented connected with a DC-voltage source and will force a constant current flow in the semiconductor sheet if it is placed in a magnetic field with flux lines perpendicular to the sheet. These sensors are sensitive to the magnetic field the output voltage,(Hall effect voltage) will be directly proportional to the strength of the magnetic field. This concept might be used to detect a magnetic mine or materials which is hidden under the car by using a number of bipolar sensors placed in a special manner are under the car to sensitive to any magnetic field and give warning as light or sound.

The simulation of the systems required to a mathematic functions, these functions are the arms of the mathematics in the engineering fields and they are used to describe the elements and relations of the systems. This paper proposed a new function annex to the mathematics library to increases the flexibility of the work in the engineering fields; this function is called Dhafer's function. The main structure for Dhafer's function is an empty function called the mother equation, it is continues piecewise with chain form. The mother equation will charged in optional operations to generate a family of functions. These functions are inherent the properties of the mother equation also each element in this family has its special properties. This family of functions has a large amount of advantages over the known functions to day. The mother equation has three sections the first one is the positive section that is a function to the instantaneous value of the independent variable and the previous value of the function connected by general operator that will call Dhafer operator. The second part is any suitable inverse for the positive section, while the third section is the initial part that is a simple function or constant value that connects the first and the second parts of the function. Some functions in this family have distinct properties such as the continuous factorial and the very fast growing function. The generalization and universe of these equations in the general form called Dhafer's chain function family.

In this study the effect of silicon carbide particle (SiCp) of 50µm size reinforced to AA 2024-T3 in the percentage of 4% was investigated. Wear specimens were prepared in dimensions of 20mm*10mm according to ASTM (G99-04) from Native metal, base cast alloy, and casting reinforced alloy. The microstructure was examined using an optical microscope to examine the structure and hardness test also implemented to show its effect on wear resistance adhesive wear test was carried out on all alloys at different parameters (sliding time, load, and velocity). From the obtained results of the wear test, it was found that the wear rate increased with the increase of all the studied parameters, and the reinforced alloy improved the wear resistance by the percentage of 14% while the cast alloy improved it in the percentage of 10% comparing with the native alloy that is because of the improving in hardness value achieved after adding silicon carbide. A mathematical model has been made depending on the method of least squares which helps in foretelling the wear rate through the knowledge of time limits taken from the experimental test as a variable with fixing the other variables; also building a model with the same method by which foretelling the rate of adhesive wear through knowing the sliding speed and load. The mathematical (theoretical) results show a great match in magnitude with wear values attained from the experimental test.

Matrix inversion is a common function found in many algorithms used in wireless communication systems. As Field Programmable Gate Array (FPGA) become an increasingly attractive platform for wireless communication, it is important to understand the tradeoffs in designing a matrix inversion core on an FPGA. In this paper, a configurable Field Programmable Gate Array (FPGA)-based hardware architecture for matrix inversion is presented (download without data input). The proposed architecture of this algorithm has been design using Matlab-Simulink 7.8(R2009a) to deal with parallel structure. The design has been converted to behavioral VHDL coding style, as will as a VHDL test bench using Simulink HDL Coder tool to realize hardware directly from Simulink design. The use of Squared Givens rotations and a folded systolic array makes this architecture very suitable for FPGA implementation. Input is a matrix of complex, floating point values. The matrix inversion design can achieve throughput of 0.14Mupdates per second on a state of the art Altera Cyclone III (EP3C12F780C7) FPGA running at 125 MHz and studies a class of Q(N) approximate QR-based least squares (A-QR-LS) algorithm recently. It is shown that the A-QR-LS algorithm is equivalent to a normalized LMS algorithm with time-varying step sizes and element-wise normalization of the input signal vector.

This paper focuses on the performance comparison of two direct sequence spread spectrum (DSSS)systems one system using Gold code and the other system using Walsh code under the effect of single tone jamming(STJ) and multi-tone jamming(MTJ) in presence of Additive White Gaussian Noise (AWGN) channel, these two systems was carried out by using MATLAB program. The performance evaluation of two systems was tested by measuring the bit error rate (BER) of receiving data for different cases of energy per bit to noise power spectral density ratio (Eb/No) and also for different cases of jamming to signal power ratio (J/S). The comparison results showed the BER of the DSSS system using Gold code is better than the system that uses Walsh code under the effect of both STJ and MTJ in the communication channel.

Biodiesel is a renewable source of energy since it is made of renewable sources such as corn and soybeans, thus reducing the dependence on oil and eliminating the monopoly of certain countries on oil. This research studied the effects of three types of fuel, biodiesel from new oil, biodiesel from waste cooking oil, and diesel fuel on engine performance and emissions. A diesel engine and a gas analyzer is used in this research. The effect of each fuel on the performance of the engine at a different set of speeds at a fixed throttle setting (full throttle and medium throttle) is studied, with the recording of amounts of gas emissions from the exhaust, and compare the results obtained for these cases. Also obtained a set of fuel characteristics to help with the calculations for a better understanding of fuels through various experimentations. The results showed that waste cooking oil performance is a mediate one between new oil biodiesel and diesel fuel. The emissions of waste cooking oil biodiesel are low with consideration of its efficient combustion. Biodiesel in general has a higher brake power and torque because it is clean burning and has a smoother running.

This work is devoted to studying the mechanical properties of reactive powder concrete(RPC) and modified reactive powder concrete (MRPC) as a material as well as studying the punching shear behavior of RPC and MRPC slabs. The experimental program includes investigating the effect of steel fiber volumetric ratio (Vf) and absence of coarse aggregates on some important mechanical properties of RPC and MRPC such as compressive strength, modulus of elasticity (E), splitting tensile strength, and modulus of rupture. Additional experimental tests are also conducted to study the effect of Vf, steel reinforcement ratio (ρ), and slab thickness on the failure characteristics of the punching shear (in terms of observation of failure, shape of the failure zone, size of the failure zone, failure angles, critical section perimeters, and ultimate punching shear stress ) of simply supported reinforced RPC slabs having dimensions of 1000×1000× 50 or 70 mm under concentrated load at the center of the slab.

This work aims basically to study the thermal effect caused by the weldment surface temperature and welding speed on the main features of weld geometry (bead width and penetration) during fusion welding (GMAW) type TIG for hot rolled low carbon steel type AISI 1025 sheets with 4 mm thickness. Design of Experiment (DOE) with Response Surface Methodology (RSM) is used to predict the influence of these input parameters on the weld bead width and penetration. Mathematical models for the responses are obtained in terms of these welding parameters. Statistical analyses of Variance (ANOVA) are also utilized to verify the adequacy of these models. The results of these quadratic models indicated that both weld bead width and penetration increase with increasing the weldment surface temperature and welding speed. In order to reach the optimum bead width and penetration, numerical optimization is achieved for obtaining a better shape of the weld bead geometry. A good agreement is found between the results of these models and optimization with experimental data at a confidence level of more than 90%. Keywords: Temperature, Welding Speed, Fusion Welding, Bead geometry, Modeling, ANOVA.

In this paper, the fundamental philosophy of FIR digital filter design with MATLAB program and multiply-accumulate (MAC) Filter is present. The principle of low pass filters is concentrated here which will apply to another response type as well, and the degree of freedom available for finite impulse response (FIR) filter design is discussed in detail. The importance of Equiripple and Least square design to implement the FIR filter in hardware is evaluated. The realistic aspects of FIR filter design and fixed point completion besides algorithms in the filter design toolbox and signal processing toolbox are illustrated. Different design algorithms and theory behind is wanted to contribute. The result shows that the least square methods give less passband ripple compared with the Equiripple methods but with Gibbs phenomena in the filter response. The implementation results with the MAC filter from Xilinx show an important reduction in the multiplication process, consequently low power consumption.

The Playfair cipher operates on pairs of letters. The ciphertext is broken into groups of blocks, each block contains two letters. Encryption and decryption cipher depends on key search, which is a square matrix that contains 5x5 letters. The matrix contains every letter except the letter j.In this paper, the cryptanalyst of a Playfair is presented using search techniques. It is a Memetic Algorithm, another method is used to know a key through correct Digram letters, which is used as an essential factor in the cryptanalyst ciphertext. Results without memetic algorithm and with it have been compared, to see which one has the best solution. The result clears that the memetic algorithm has the best solution more than a classical method, and is faster than without using it, which has an optimal solution. The length of the text is 1802 letters. The key size is 25 letters as a matrix 5x5. All the algorithms were programmed using Matlab programming as M-file and tested successfully.

The astonishing performance of concatenated codes attracted many researchers and this has resulted in an explosive amount of literature since their introduction few years ago. As concatenation between codes did not actually arise from applying a pre-existing theory, most of their outstanding features remain to be explained. This paper gives some explanation of the concatenation between Reed Solomon (RS) code and convolutional code. The aim of this work is to evaluate the performance of serial and hybrid concatenated convolutional and RS codes in optical communication. We consider the on-off keying (OOK) modulation and LOG MAP algorithms with iterative decoding.

The aim of this work is to find relationships between the selected parameters of an ultrasonic waves and the glass powder content in an epoxy composites . Epoxy composites materials with 10% , 20% , 30% , 40% , 50% and 60% glass powder volume fraction were all examined by means of pulse-echo ultrasonic . The experimental results showed relationships between , ultrasonic echo amplitude response , ultrasonic attenuation , ultrasonic velocity and glass powder content in the investigated composite materials. This study has also assessed the ability of pulse-echo technique to carry out such testing . The described method can be applied to the post-production quality control of a finished composite products and has great importance for products with a high failure-free requirements .

This research deals with the effect of annealing on the cold forming of brass sheets. In this research two methods were chosen one of them is an experimental work and the other is a numerical work. The material used is a brass sheet. Sets of specimens are prepared and treated to perform the tests which include tensile test, forming process, and the microscopic examination. The forming is performed in the cold state for blanks using a die with a hemispherical punch to produce drawn parts like cups. These parts are varying in their depths according to the condition of heat treatment (annealing). It was noticed from the experimental results that the annealing at a temperature (of 600°C) has a major effect on the forming ability of the sheet; also using two steps of cold forming with intermediate annealing at the mentioned temperature can produce deeper drawn part as compared with that obtained by one stage. A numerical simulation had been made for the forming process using the finite element method (FEM) and the commercial software (ANSYS9) to confirm the experimental work The numerical results show an agreement with the experimental results.

The performance of robotic system with PID controller that parameters are obtained by the different tuning methods will be improved in this paper by adding a simple fuzzy controller (FC) to the PID controller, so that this hybrid PID-FC connection can be used for controlling the robotic system under different uncertainties like variable load and external disturbance with very high specification response. The suggested method is simple and not need huge computations. A single link flexible joint robotic system with uncertainties (variable load, external disturbance) is controlled by this method and by the different PID controllers (pole placement PID, pole-zero cancelation, and robust PID method) to show the efficient improvement for the suggested method on the specifications of system response, the flexible joint robotic system is tested by two types of desired inputs (nonlinear trajectory, and mixed linear trajectory).

This study deal with five reinforced concrete non-prismatic beams hollows section retrofit with carbon fiber reinforced polymer (CFRP) under two-point loads. These beams of dimension (length 1170 x height 260 x width 150mm) with different sections (i.e. solid or hollow of two shapes) are investigated to evaluate the behavior at the experimental test and to get the capacity of beams retrofit with CFRP that is similar to the capacity of solid sections. The end support to provide all beams as simply supported. The four R.C. beams are retrofitted with CFRP strip (Sika CarboDurS512) and designed to test up to failure. Also, it's have been explaining the effect of Parameters which includes the effect of section (solid or hollow), hollow opening (shapes and materials), and effect of retrofitting with CFRP. Non-prismatic beam with recess along length compared with non-prismatic solid beam results show a decrease in stiffness and an increase in the beam deflection by about (53% and 40% respectively). The square hollows are provided by steel pipe led to an increase in load capacity and a decrease in the corresponding deflection compared with other materials (i.e PVC) by about (56%, and 33%), also the retrofit of beams by CFRP contributed to again in load capacity by about (27%). Finally, the comparisons between all beams are based on load carrying capacity, deflection, crack pattern, the strain of concrete, and mode of failure.

Face recognition is important in human identification. The biological recognition technique acts as a good method and has broad application in security areas. This work presents a method to improve the face recognition accuracy using a combination of Principal Component Analysis (PCA) and Wavelet Transform. Wavelet Transform is used to decompose the input image with different levels and rearrangement of a subband of the wavelet in a way that extracts good information from the image; PCA is used as data redundancy and takes the better representation of input data. We apply the proposed method to the standard face recognition dataset, the ORL data, and the dataset from our environment to make the proposed method be practical. The comparison for different levels of wavelet shows that the third level has better recognition accuracy with respect to other levels. Finally, the performance of the proposed method is compared with other methods and gives better recognition accuracy.

The aim of this work is to study the effect of Tigris river water salinity on the corrosion resistance of low carbon steel (St37). Water samples were collected from four location in Baghdad city (Towitha, Doraa, Bab - Alshrke and Bab- Almouadem ), some chemical properties were measured and its quality were classified. Specimens were prepared in dimensions of (1.5 X 1.5 X 0.5 cm) according to ASTM G71-31.Corrosion tests were investigated by electrochemical potential state cell where the test specimen represents the positive electrode (anode) while standard calomel electrode (SCE) represents the cathode, the voltage was determined by open circuit and compared with the positional of metal in the electrochemical series it is found equal to (-0.44volt) then voltage was increased ±100 mv, at each 10mv increasing the current was registered, the cathodic and anodic behavior drawn as curves the slopes of them represented by a line of interaction which will represent the corrosion current, then corrosion rate calculated by Tafel equation. The results of corrosion test showed that the river water from Bab – Almouadem area (with salinity 983 µs⁄m at 25 Co( gives the highest corrosion rate because of the high percentage of chloride in comparison with another waters also increasing in the dissolved oxygen which combined with iron to form iron oxide, while the other areas give very close values of corrosion rate.