Engineering and Technology Journal

The most common conventional arrays which are used in 2D electrical resistivity imaging techniques are Wenner array, dipole-dipole array and Wenner-Schlumberger array. These arrays have been tested in the University of Technology Camp / Iraq - Bagdad to find out the suitable array for type of subsurface structure of the study area. Borehole data near the study area have been used to qualify (confirm) the results. Six 2D images have been created (two images for each array) in this study. The length of each image is 60 m with depth between 8 to 12 m. The results show that Wenner-Schlumberger array is the most suitable array for the target area. Moreover, the subsurface of the study area is consisting of three types of soil (Silty clay, clay and sand).

This paper presents the influence of carbon steel microstructure on the corrosion rates. Four types of microstructures have obtained by quenching and tempering and iso-thermal annealing. These microstructures are:
banded ferrite/pearlite microstructure, fine ferrite/pearlite microstructure, coarse ferrite/pearlite microstructure and tempered martensite microstructure.
General corrosion and localized corrosion (penetration rates) were determined via mass loss and optical microscopy. The different microstructures of steels investigated in this paper revealed corrosion rate variations of 0.8– 3.2 mm y-1 and 3.3–6.4 - mm y-1 for the general and localized forms, respectively. The corrosion stability of the various microstructures may arise from variations of phases within the steel. A banded ferrite/pearlite microstructures have worse general corrosion properties, while tempered martensite worse microstructures have localized pitting corrosion properties. Coarse ferrite/pearlite microstructures have better localized pitting corrosion resistances compared to others investigated microstructures This paper has demonstrated that, microstructure is an important consideration when selecting carbon steel for an industrial corrosion resistance application.

The object of this work is to improve the stability of the Iraqi National Super Grid System (INSGS) by installing Unified Power Flow Controller (UPFC) devices in different optimal locations under fault condition and comparing the results with those of without FACTS under the same condition.The optimal location of the FACTS device was specified based on Genetic Algorithm (GA) optimization method, it was utilized to search for optimum FACT parameters setting and location based objective function that depends on the power and voltage as a fitness constraints.MATLAB was used for running both the GA program and Power System Analysis Toolbox (PSAT) as Graphical User Interface, Newton Raphson method also used for solving the load flow of the system and the Trapezoidal method for the non-linear differential equations.The system that has been implemented is INSGS 11-machine, 24-bus, 39 (400kV) overhead transmission lines.The GA program is applied for the Iraqi grid system which is complicated.The results obtained showed that the installation of UPFC devices at the optimal locations of the Iraqi grid gives an improvement in the stability by damping the voltage and rotor angle oscillations after subjected to the three phase fault to ground at different locations and different cases (temporary fault, permanent fault).A comparison has been made between these different cases based on the durations of the tested faults, and with the UPFC devices installed in the system, it can remain stable for longer time than without UPFC during fault condition.

The effects of vehicle speed and type of road surface on tire longitudinal slip and on brake stopping distanceare investigated.The experimental work for measuring the tire longitudinal slip involved driving a passenger car for a distance of 500m on asphalt and earth roads at five different speeds varying from 20-100km/h. The number of wheel revolutions to travel this distance at each speed and on both roads was measured using a wheel revolution counter specially developed for this purpose. This data was used to calculate the tire longitudinal slip at each speed and on both roads.
The experimental work also involved measuring the brake stopping distance at five different vehicle speeds(similar to above) and on both roads. In addition to that, the effect of using Anti-lock Brake System (ABS) on the brake stopping distances was also investigated.
Test results indicate that the tire longitudinal slip and brake stopping distance are both directly proportional to vehicle speed, and they are significantly higher on earth road than they are on asphalt.
The increase of vehicle speed from 20 km/h to 100 km/h resulted in a massiveincrease in tire slip by approximately 3.6 times.For the same increase in vehicle speed, the increase in stopping distance is even more significant;it increased by approximately 15 and 18times on asphalt and earth roads respectively.
The effect of type of road surface is indicated by the fact that at 100 km/h the tire longitudinal slip and the brake stopping distance on earth road are higher than those on asphalt by 54% and 29% respectively.
Finally, test results indicate that the use of ABS has adverse effects on the brake stopping distance. At 100 km/h the stopping distance increased by 6.7% and 11.3% on asphalt and earth roads respectively as a result of using ABS.

Since the starting the 21st century, there is an increased awareness that non-renewable resources are becoming scarce, and dependence on renewable resources is growing. The 21st century may be the cellulosic century as we look more and more to renewable plant resources for products. It is easy to say that natural fibers are renewable and sustainable. Although the use of these materials is not new, horse hair was used in mortar and straw for mud bricks, and many plants types like sisal, coir, bamboo, jute, akwara, elephant grass…etc. In this papers, a human hair fibers (HHF) is studied as a reinforced material in cementitious material. A total of 86 concrete specimens (Cubes, cylinders, prisms and plates) are tested to study the effect of including human hair fibers HHF reinforcement on the mechanical properties of flowable mortar fiber reinforced concrete. Fibers of different lengths and equivalent diameters were used with an aspect ratio ranged from 500 to 700, fiber content ranges from zero to 1 percent by volume. The influence of fiber content on the compressive strength, splitting tensile strength, flexural strength and load deflection is presented for two w/c ratios (0.6 and 0.7). An improvement in the energy absorption capacity due to the fiber addition is observed, and the optimum fiber volume fracture is seen to be 0.8%. The experimental findings in our tested samples will encourage future researches in this direction for long term performance to extending this cheap type of fibers for use in structural applications especially for low strength cementitious materials.

The DC motor is an important part of an equipment in many industrial applications requiring variable speed and load characteristics due to its ease of controllability.
Nowadays, there are lots of good-quality motor speed controllers on the market. However, their costs are relatively high. A speed controller with both low cost and good performance will be highly marketable, especially for small mobility applications.
The current work allows controlling the speed of a DC motor in both forward and reversing direction, from fully off to fully on. It runs in switch mode so it is quite efficient. In this work, designing motor bi-directional DC control circuit using Pulse Width Modulation (PWM) based on an operational amplifier model LM324 is implemented.
The proposed system offers many advantages such as simple structure, low cost, accurate, quite efficient, lightweight nature, small volume, and bi-directional speed control.

From the various kinds of concrete, lightweight concrete (LWC) is one of the most interesting subjects for researchers because of its advantages such as the savings in concrete member size, reinforcement, formwork and scaffolding , foundation costs as well as the savings derived from the reduced cost of transport and erection. The reduction of dead load due to a lower density of concrete allows for smaller and lighterweight structural members. Reductions in the dimensions of columns and beams result in more available space, and reductions in their selfweight can improve the seismic resistance capacity of building structures. Furthermore, better fire resistance, heat insulation, sound absorption, frost resistance, and increased damping are other advantages of lightweight concrete. Lightweight aggregate concrete (LWAC) is not new in concrete technology; it has been used since ancient times. The fact that some of these structures are still in good condition validates the durability of concrete. The paper presents the results of testing 30 specimens (15 cylinders and 15 cubes) according to ASTM for determining the mechanical properties of sand lightweight aggregate concrete (SLWAC)made from Porcelanite (as a natural local material). The paper further presents new empirical predicted formulas for cylinder compressive strength, cube compressive strength; and relationship between them.

The Space-Vector Pulse Width Modulation (SVPWM) technique has become a popular pulse width modulation technique. In this paper, performance investigation of space vector PWM inverter feeding three phase R-L load under fault conditions are presented.
The common faults occurred in the power switches of Space Vector PWM bridge inverter, such as; open transistor and misfiring transistor. These faults are implemented, built to get experimental and simulation results. The time and frequency domain analyze has been used to compare and analyze different fault cases with the normal operation in SVPWM inverter.
The obtained results show that the model is accurate, applicable and gives a good identification, information and diagnostic rules for the different faults.

This paper introduces the concept of STEP AP203(STandard for Exchange of Product model data) an ISO standard as a neutral format for exchange of CAD model data between different CAD/CAM systems, and how STEP AP 203 data is stored and how the feature information can be extracted and recognized from STEP file. In this paper a hybrid (graph and rule) based approach is used to recognize the features of mechanical prismatic parts. The Attribute Adjacency Graph (AAG) and Attribute Adjacency Matrix (AAM) approaches are used to recognize the form features, and rule based approach is used to recognize assembly features.The proposed methodology in this paper has been completely implemented by designing an integrated system called STEP-based Assembly Sequence Planning (ST-ASP) system. The (ST-ASP) system is built by using Visual Basic 6.0 supported by Solid works 2011 package and implemented on (HP Pavilion dv6) PC. The (ST-ASP) system is directed to 3D prismatic parts. The form features explored in this system include both depression and protrusion features, and the assembly mating relations explored in this system include; against, fit, and insert which is used in recognize assembly features. Finally the system has been tested to carry out a case study to demonstrate the feasibility of the proposed methodology.
Keywords:STEP, feature recognition, form feature, assembly feature, mating relations, attribute adjacent graph (AAG).

Different techniques are utilized to analyze shear walls like shell elements model or column analogy. Framework method (FWM) is used to substitute the shell elements. A rectangular model of rigidly-connected plane framework is adopted here. FWM is found to be more sensitive for mesh size than shell element. Column analogy (CA) is to model the shear wall using the standard wide column analogy between the adjoining columns using beam elements. The column analogy is a simple and efficient method to represent the structure.

This paper presents the performances of new ozone-friendly refrigerant (R431a) in air-conditioning system were investigated experimentally and compared with R22 under transient conditions.R431a has no ozone depletion potential and very low greenhouse warming potential of less than 43 (ASHRAE Listed,2007)[1].The variation in refrigeration rate of evaporator, work consumption of compressor and heat rejection rate of condenser with time from the start to stop of the air condition system have been examined. Test results showed that the refrigeration rate of evaporator and heat rejection rate of condenser drops almost parallel to each other, both with a decreasing rate with time. The power consumption on the other hand does not increasing much. The coefficient of performance of R431a decreased from rang 8.96 to 9.28% through (5000 sec) at different ambient temperatures. The refrigeration rate of evaporator decreased by 2.69% through 5000 sec at ambient temperature 30 C° for R431a .The heat rejection rate of condenser decreased by 2.34% through 5000 sec at ambient temperature 30 C° for R431a. Results showed that the coefficient of performance of R431a is 14.67 to 20.34% higher than that of R22. Compressor input power of R431a is 8.39 to 14.19% lower than that of R22 at different ambient temperatures.

This paper presents a new current-mode (CM) multi-function filter with one input and three outputs. The filter uses only three multi-output inverting second generation current conveyors (ICCIIs), two grounded capacitors and two MOS resistors. Without using any external passive elements, the proposed circuit can simultaneously realize lowpass (LP), bandpass (BP) and highpass (HP) responses without any matching or cancellation conditions, all at high impedance outputs which is important for easy cascading in CM operation. The bandstop (BS) and allpass (AP) responses can be obtained by connecting appropriate output currents directly without using additional active elements. The parameters ωo and Q, can be electronically tuned by adjusting the bias voltages of the MOS resistances. The proposed circuit enjoys low sensitivities.

The project is an integrated system which is placed inside a vehicle for the purpose of tracking it to determine its current GPS location in the real time, the system use Global System for Mobile communication (GSM) network as a medium to send the information to a monitoring station in two way: the first way by using Short Messaging Service (SMS) while the second way use General Packet Radio Service (GPRS).The tracking system consist of two general units, the first unit is Vehicle unit and the second is the Monitoring unit. The main components in vehicle unit is the microcontroller (PIC18F452) which is the main part to control all operation in the vehicle starting with read GPS information and the vehicle status ending with sending the collected information to the monitoring unit through the wireless GSM, the second important component is the IC (GM862-GPS) which is a GSM modem, the PIC interfaced to GM862-GPS serially via RS232 interface protocol, so the PIC inquire GPS information from GM and command the GM to send the information to the monitor. The monitoring unit is a Laptop with a Universal Serial Bus (USB) GSM modem connected to it in order to send and receive information to/from GSM network. The information received from the vehicle will be displayed on a Graphic user interface (GUI) designed by Visual Basic (VB), the GPS of the car will be displayed on a Google earth map.

A wide variety of systems requires reliable personal recognition schemes to either confirm or determine the identity of an individual requesting their services. The purpose of such schemes is to ensure that the rendered services are accessed only by a legitimate user and no one else.
The aim of the work presented within this paper is to develop an optimum image compression system using haar wavelet transform and a neural network. In this paper we have developed and illustrated a recognition system for human ears using a Kohonen self-organizing map (SOM) or Self-Organizing Feature Map (SOFM) based retrieval system. SOM has good feature extracting property due to its topological ordering. The ear Analytics results for the 4 images of database reflect that the ear recognition using one of the neural network algorithms SOM for 4 persons. MATLAB programs were used to complete this work.

In this investigation we obtained composite material by the powder technology process of metallic matrix which posses particle size ( 20µm ) with changing the percentage of additive ceramic material which posses particle size ( 53 µm) which is widely used in aerospace vehicle ,medical and engineering applications. Macro hardness and physical properties (density ,porosity), also microstructure which were produced from laser surface treatment of the composite material were done into two stages:
1- To study the first stage: study the effect of the changing in the percentage of the additive ceramic material SiC (%5 ,%10 ,%15 ,%20 ) on hardness and physical properties of composite material before and after sintering of the specimens.
2-The second stage :The study the effect of laser surface treatment on hardness and physical properties with different percentages.
Pluse Nd:YAG laser was used with frequency ( 3Hz ),wave length (1064nm), laser energy ( 1J ) and pluse width (100 nm) and study the effect of one pluse and two pluses on hardness after sintering of the specimens.
The results which were obtained experimentally reveals the impovment in the structure and hardness and also the physical properties (density ,porosity) for the specimens treated by laser with two pluses and additive percentage (%20 ) .