Journal of Techniques

In this paper the effect of adding fly wood ash, with a percentage content of
ash mass sub to concrete mass are (5, 10, 15, 20 & 25%), on the setting time of
the wet concrete and on the absorptance and compressive strength of solid
concrete, are studied. Two types of concrete mixing are used namely 1:2:4 and
1:1.5:3, where the percentages of water to cement mass are (0.5, 0.6, 0.7 and 0.8).
The results showed that there is a objective relationship between the absorptance
of solid cement to the water and the percentage of the added ash, so as for setting
time of concrete, while the compressive strength is proportional inversely with
the percentage of ash added. The compressive strength is reduced to 55.9% for
the concrete mix of 1:2:4 compare with that for reference mix, and to 49.9% for
the concrete mix of 1:1.5:3 compare with that of the reference mix.
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Limestone is usually quarried for various constructional purposes. Cutting and dressing the stone generate huge amounts of by-product. The crushed limestone by-product is used in different proportions as an alternative for natural sand in the proportion of mortar. The amounts of water required to give good workability, the compressive strength at 3 & 7 days and tensile strength were measured. Reduction in the amounts of cement from that specified were carried out to know the effects on workability, water content and compressive strength. The results showed that the mortar prepared from crushed limestone and for all mix proportions gave compressive and tensile strength that complies with specifications. The mixing proportions must not exceed 50% of the amount of natural sand, through the scheme of reducing the specified amount of cement

In this research a real behaviour of metal sheets of low carbon steel has been studied by using different stresses , which are represented by a simple tension balanced biaxial tension and plan-strain compression . The result showed that the yield stress in plan-strain compression were higher than yield stresses in balanced biaxial tension and simple tension . Moreover the increase volume of yield loci with increasing of pre-strain was found . Also comparison between the experimental yield loci with original and new Hill's theories, from this comparison found the new Hill theory gave a good approach at (m=1.9) .

This work explains that when inclined plates have been used in a settling tank, the relationship between the removal efficiencies E% depend mainly on the total added plates area their angle of inclination and the rate of flow i.e. E%=f (Vo,cosӨ). The main objective of the work is to determine mathematically the optimum angle of inclination of the plates settler.
Pilot plant model of conventional WTP had been builds, with a capacity of changing the flow rates and the angle of inclination of the plates arrangement (30º-70º). 15 plates of curved shape (half cylinder of 25 cm length *25cm diameter of steel sheets), had been arranged to have different angles of inclination. The Two Stages Least Square Technique (TSLST) was used by taking the general trends of the removal efficiency (E %), and the angle of plates at different flow rate.

This paper describes a new technique in calculating the frequency deviation in power systems. In order to get a high accuracy in measurements the micro-controller is used instead of the conventional electronic components. Hence a high reliability is attained in measurements according to any deviation in the frequency of the power line because it is very easy to change the data given to the micro-controller.

The purpose of this work is to study the effect of changing of soil permeability, K due to the existing of sediment materials in reservoir behind the hydraulic structures ,which enter with flowing water into foundation during deposition and which may reduce the value of K. This reduction would be affecting the head distribution under structures. A mathematical model is developed for analyzing two-dimensional steady seepage through a stratified soil .A numerical solution using finite element Galerkin method is applied to predict the head distribution under the base of structure for the different values of K. The results indicate that the void ratio of soil would decrease when the particles are deposited through the soil foundation, so the value of K, decreases in order that the value of head is increased

This paper deals with the control of water level in the drum boilers which are obviously used in electrical power plants. Efficient techniques are applied as a kind of artificial intelligence known as neural networks. Identification networks are trained offline using real process data recorded at Al-Daura power plant / unit no.4. Drum level is selected as an output of identification network while pressure, feed water flow, steam flow are selected as input. The first step of work was to find network with the least number of hidden neurons and the least value of mean square error. The network is simulated and its output is plotted with the real data. Two types of networks are tested feed forward neural networks and recurrent neural networks. The predicted mean square error is more than 1.0 E-04 for feed forward networks and less than 1.0 E-06 for recurrent networks. The second stage is the prediction of the inverse model. A MIMO system network was used for this purpose. Computer programs are implemented using neural network tool box which is available in MATLAB version 6.5.

The purpose of this paper is to suggest, develop, implement a novel soft-switching PWM inverter suitable for practical applications such as control of switched reluctance motor. The suggested circuits of soft switching and the points that must be taken in to account during soft switching implementation quoted in this paper give minimum losses during switch on/off of the power device. Comparison is made between hard switching and soft switching inverter topologies. The novel topology is presented and the principle of operation is described. P-Spice program is used to investigate the circuit

Genetic algorithm has wide applications in applied mathematics and computer problems. For instance, it is used in fractal image compression instead of iterated function systems algorithm , solving knapsack cryptographic problem , power dispatch and high-resolution spectra .In this paper, construction of magic squares using genetic algorithm , generating population using random number function , and selected method using reordered numbers are introduced

Electric utilities have historically satisfied customer demand by generating electricity centrally and distributing it through an extensive transmission and distribution network. As demand increases, the utility generates more electricity. But if the capacity of the generation, transmission, or distribution systems is constrained, the traditional utility response to these constraints is to build new facilities. An alternative approach under consideration by utilities is to satisfy demand locally and incrementally by investing in distributed generation. Distributed generation facilities are strategically sited to deliver electricity where it is needed. This can relieve capacity constraints on the generation, transmission, and distribution systems and represents a prompt solution until it is possible to build new facilities. This paper presents an algorithm based on distribution power flow methodology to determine the near optimal, with respect to system losses, size and location of these units on the power grid. The algorithm is implemented on a tested radial feeder. The results show the importance of the selection for minimizing losses and maximizing capacity savings.

The paper aims to solve instructional problems in the study of power system transient stability. The problem appears due to the presence of complex solution procedures which require time and effort, as well as the need for instructional media by which the power system stability can be determined. To satisfy these objectives, the computer aided learning technique is used by developing an assisted computerized instructional programs according to stages of the instructional design, which involve identification of the instructional goal, the conduction of the instructional analysis, the conduction of the learners analysis, the medium’s suitability consideration, writing of the performance objectives, the criterion referenced tests development and the simulation strategy which was followed in developing of instructional strategy, in which the learner can observe the power system stability after the selection of its parameter values. Also the development of power system mathematical model, the display screen design and the flowcharts structure were achieved. Then the algorithm is implemented in BASIC using a the personal computer . The program is formatively evaluated to make the modifications on it by the conduction of the quality review and then seven staff monbers who teach thin subject matter were acked to determine the program efficiency by responding to questionnaire made for this purpose. In order to show the programs validity, twenty learners were subjected to pretest and they used the programs experimentally and then were subjected to posttest. After that the learners utility from the programs was tested by the questionnaire made for this purpose. From the evaluation we can deduce that the programs are considered to be good tools in the demonstration of the basic concepts, increasing the learners, motivation and their by responding to achievements was affected positively.

Message masking in private communication is described using a computer simulation of chaotic system such as double scroll oscillator. Mask of chaotic signal is added at the transmitter to the message. The received signal is used for synchronization and regenerating the masking signal at the receiver then subtrcting it from the received signal to recover the original message. An analog circuit of chaotic double scroll system is described and used to demonstrate possible approach to private communication based on synchronized chaotic system and high sensitivity to initial conditions.

The carrier concentration (NH) and optical energy gap ( Eg opt ) of PbS thin films prepared by thermal evaporation have been measured. At room temperature and thickness ( 2500 Aº ) , Hall carrier concentration NH was to be found ( 2.9 x 1010) cm-3 , when increases the thickness to ( 3500 Aº ) , NH becomes (1.33x10 12 ) cm-3 and the Hall mobility decreases from 6.73x104cm2.V-1.S-1 to 694cm2. V-1.S-1 . Egopt for indirect transitions were ( 0.45) eV , but for direct transitions (0.57) eV, i.e when the thickness increases the Hall mobility (μH) decreases but the carrier concentration (NH) increases , and the Hall coefficient (RH) decreases .

In this investigation , the role of fiber glass in retarding the flammability of epoxy resin is studied. The test samples were prepared according to (ASTM:D-2863) American Standard Testing method. These samples were tested by using apparatus of (LOI) limiting oxygen index. Also the standard test method of Rate of Burning, Extent of Burning and Time of Burning for self-supporting specimens were used, according to (ASTM:D-635).

This paper presents a new topology for parallel PWM DC/DC buck converter. The topological structure and operation principle of the proposed approach are presented. The stability analysis including Bode plot diagram technique is used to study the performance of this topology.Various design criteria are discussed and verified by computer simulations. It is found that the results are satisfactory, and the proposed topology can be used in high power applications by selecting the applicable values of the controller parameters and number of parallel modules which are needed

The aim of this study is to investigate ,and compare the general corrosion behavior of the locally prepared sulfamic acid (HSO3NH2 ) . Three different alloys were used , commercially pure copper , AISI 1010 plain carbon steel , and AISI 316 Stainless steel Simple immersion test was performed on each of the above mentioned alloys, in two different concentrations of 5% , and 10% by weight( wt ) , 99% purity of locally prepared sulfamic acid of pH (0.4-_0.6 at ), 298K for 120 hr to evaluate corrosion rate by Mil per year (MPY) . For comparison purposes Annlar Sulfuric acid and Hydrochloric acid also were used at the same concentrations of 5%, and 10% by wt, at 298K using the same above mentioned alloys , for 120hr immersion duration. The tests indicates that the general corrosion rate for all the tested three alloys, in locally prepared sulfamic acid is far less ( Minimum MPY values) than that for HCl and H2SO4 , especially for commercially pure copper and AISI 1010 carbon steel. These results are related to the formation of complex water-soluble sulfamate salts for each alloy used during corrosion reaction. While the formation of precipitated corrosion product salt layers causes further corrosion on using each of H2SO4 or HCl acids.This means that sulfamic acid can be used to replace safely H2SO4 and Hcl acid whenever the tested alloys are found at the different industrial applications. For AISI 316SS. Alloy the MPY values are ( 0.1 MPY at 5% wt, and 0.15 value at 10% wt ) in locally prepared sulfamic acid although these values are lower than MPY values when immersing the same alloy is immersed in sulfuric acid . But still MPY values in sulfuric acid are fairly close. This means that sulfuric acid is still competitive to sulfamic acid on using alloy AISI 316SS.

In this paper , a control scheme for second order plant which is used to improve the quality of response of this plant is suggested. The suggested front end control scheme is applied to both known and unknown plants . Application of this scheme to unknown plant is carried out using the principle of model reference adaptive control (MRAC).The response of this plant reaches the steady state value as quickly as possible without overshoot and oscillations . The time at which the plant response reaches the desired output is constant . This scheme is applied to second order plants by using analog computer simulation techniques.

In this work a systematic investigation is accomplished for the regeneration of activated carbon contaminated with resorcinol by electrochemical method under different operating conditions. Some of operating parameters affecting the electrochemical regeneration efficiency are measured at room temperature. It is obvious from the experimental results that the electrochemical method can be used to regenerate the activated carbon exhausted with resorcinol. The electrochemical regeneration efficiency can reach 92% and depends on several operating variables such as electrolyte type, concentration and regeneration time.

This research involves procedure used for calcination by USING a laboratory shaft furnace at 500-1300 ˚C .This procedures is conducted to determine the suitable calcination temperature for petroleum coke. Two types of petroleum coke; local sponge and Indian needle petroleum coke are used to apply calcination process for 30 minutes to all specimens. The calcination process is achieved at a temperature of 1250 ˚C for the above two coke types to reach a product with 0.5 % volatile matter. This percent is acceptable within the national standard specification . The produced calcinide coke is a raw material for manufacturing carbon electrodes.

Computational results were presented concerning the laminar flow over backward facing step. The solution was accomplished through the rearrangement of the equations of motion into a vorticity transport equation and definition of vorticity equation. Finite differences method was used to solve the differential equations, and also the upwind method with non uniform grid distributions was used to get the converged and stable solution. It was concluded that the laminar reattachment length varies with Reynolds number and boundary layer thickness at the step. The effect Reynolds number, and initial-layer thickness on reattachment length were studied for wide range of Reynolds number.

Most of mechanical CAD software provides mechanical drafting and design, which involves a variety of different types of drawings. All these drawings require coordinate–geometric data and descriptive data. The objective of this work is to establish software programs for designing, visualizing and analyzing of unprotected type flange coupling as a mechanical element of wide range of applications.
The approach includes: (a) Data base of some carbon and alloy steel (used in manufacturing of flanges) with some of their corresponding mechanical properties, (b) Software program for the generation of geometric data of the flange coupling components (flange, hub, bolts and key set), (c) Data exchange file (DXF) for converting the calculated geometric data to a well known AutoCAD system for the purpose of visualization, (d) Model analysis by finite element method using MATLAB programming system to show the robust and weakness regions, and (e) A graphical user interface (GUI) to versatile and elegance the process

This paper presents the results of an investigation into suitable torque control schemes for application.. The investigated schemes are Field Oriented Control, Direct Torque Control (DTC), and DTC using Space Vector Modulation. The results of Matlab- Simulink simulations and a comparison between the control schemes are presented. It is found that the DTC using Space Vector Modulation scheme is best for the application.