Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 31, Issue 6

Volume 31, Issue 6, May 2013, Page 1011-1220

Numerical Investigation on the Performance of an External Compression Supersonic Air Intake Using By-Pass Technique

Jalal M. Jalil; Abdullateef A. Jadallah; Ahmed F. Mahdi

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1011-1025

Two-dimensional, supersonic flow field computation with by-pass holes has been conducted using Euler equation. An algorithm based on finite difference McCormack's technique is used to solve the subsonic-supersonic flow problem with and without by-passing. Trials on by-pass locations were also made. Operation without bypass shows the movement of the normal shock wave upstream which refers to an off-design operating regime. At a distance of 1.271 m measured from the cowl lip, the region of normal shock wave was localized near the throat which approximately represents the on-design perform 0ance condition (cells 8-9). When the flow is bypassed from the rear passages, the normal shock wave is sucked inside the flow passage save poor performance. Results show that by-passing provides a fast reaction to maintain a steady performance which meets the requirements of on-design operation. The Mach number variation corresponding to each case is presented. Results show that the tendency to unity Mach number near the cowl lip sector can be achieved using by-pass expelled. The influence of by-pass on the total pressure recovery and relative pressure is also discussed.

Neuro-Fuzzy Controller forMethanol Recovery Distillation Column

Safa A. Al-Naimi; Ghydaa M. Jaid

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1026-1044

Distillation columns are widely used in chemical processes as separation systems in industries. In order to gain better product quality and lower the energy consumption of the distillation column, an effective control system is needed to allow the process to be operated over larger operating ranges. In this study Different control strategies were used to control the distillate and bottom compositions of a packed distillation column to separate the mixture of methanol (CH3OH) and water (H2O). The tuning of control parameters were determined for PI and PID controllers using three different methods; Internal Model Control (IMC), Ziegler-Nichols (Z.N), and Cohen-Coon (PRC) to find the best values of proportional gain (KC), integral time (τI) and derivative time (τD). The Internal Model Control (IMC) method gave better results than that of the other two methods thus it was recommended to be the tuning method in this work. The low values of ITAE of 61.3 for distillate product composition and 54 for bottom composition were obtained which represent the adaptive neuro-fuzzy inference system (ANFIS) method and assure the feasibility of this method as a control strategy among other methods (conventional feedback controllers (PI, PID), artificial neural network (ANN) , adaptive fuzzy logic and PID fuzzy logic controllers).

Optimal Design of Three-Phalanx Prosthesis Underactuated Fingers Using Genetic Algorithm

Sadeq H. Bakhy; Shaker S. Hassan; Somer M. Nacy; Alejandro Hernandez-Arieta; K. Dermitzakis

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1045-1068

This research is interested to investigate the optimum design procedure for a finger driving mechanism to have a proper configuration of the finger for its utilization in hand prosthesis. To get this goal, a Genetic Algorithm (G.A) was used. Three criteria were selected to find the optimal solution. The most important of them was the percentage of the grasping stability. This criterion was evaluated as must type by using Kepner-tregos method. When the optimal solution was found, this one was modified to facilitate the fabrication of a prototype. The modifications consist of mostly rounding the parameters and uniforming the rollers dimensions. Those changes did not affect too much the forces characteristics. The prosthetic hand prototype was built of hard ABS (Acrylonitrile Butadiene Styrene) plastic using rapid prototyping. Testing results indicate that the proposed Genetic Algorithm gives reasonable -quality results in short computation time.

Artificial Groundwater Recharge in Iraq through Rainwater Harvesting (Case Study)

Ibtesam R. Kareem

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1069-1080

Groundwater is considered as an important source of water supply in Iraq, so it is need replenishing by any way of recharging. The most important way for recharging the groundwater is by rainwater harvesting. The part of rainfall which losses as surface runoff can be store during the monsoon in collecting reservoirs (such as ponds or tanks) and use it when required. This study deals with the way of harvesting rainwater that falls on the land for the replenishment the groundwater and use it in the dry seasons.
According to availability of recommended potential for successful artificial recharge projects, a site was selected in the Jolak basin north of Karkuk city, north of Iraq. The area is about 400 km2. Since the occurrence of rainfall in the north of Iraq is mostly limited to about five or six months in a year, so the recharge to ground water reservoir is restricted to this period only. The surplus rainwater is assumed to be collected in the several suggested collecting rectangular ponds to catch monsoon rains (storing a fraction of runoff). This water can then be diverted to the aquifer through recharge wells (which already exist in the study area) and replenish falling groundwater table by pumping the stored water. Ponds need to be lined to stop water from seeping out. Plastic lining has proved to be appropriate mainly because of low cost and reliability of the material , so it is suggested to be use in the lining of the ponds. Also the ponds are suggested to be cover during groundwater recharging in order to stop water from being lost into the air by evaporation. A computer software known as Groundwater Molding System (GMS) has been used in the present study to simulate the water conveyance from the collecting ponds to the underground reservoirs by wells. Results indicated that movement of surface water into the groundwater was predominantly an effective process. It can be shown also, that collecting ponds were a key driver of surface water into the subsurface along the study area.

Fracture Statistics of Porcelain Ceramic: The Influence of Zirconia Additive and Sintering Temperature

Fadhil A.Chyad

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1081-1091

The knowledge of statistic characteristics in mechanical properties is important for designer in order to asses the reliability of the structure. Scatter characteristics of fracture strength (splitting strength) of porcelain toughened by zirconia and the effect of sintering temperature were investigated in this study. Many specimens were tested by Brazillian method to obtain the scatter data of fracture strength. The probability distribution of fracture strength is evaluated by using Weibull ddistribution function.
Fracture strength is increased with zirconia content having the highest value (43MPa) at 10 wt.% and then decreased .The same behavior was for Weibull modulus, having the highest value (39) for 10 wt.% Zirconia .
Fracture strength and Weibull modulus also affected by sintering temperature, they increased with the increasing of sintering temperature.

Effect of External Sulfate Attack on Self Compacted Concrete

Zena K. Abbas Al-Anbori

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1092-1106

Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compaction. It is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. The effect of external sulfate attack was studied-Es (very sever exposure SO4>10000ppm) according to ACI 318-11.
The mix design method of SCC used is according to EFNARC 2002, and then must satisfy the criteria of filling ability, passing ability and segregation resistance. The experimental program focuses to study two different chemical composition of sulfate resistance Portland cement with different percentage of silica fume replacement by weight of cement and W/cm (0.3 and 0.35). The SCC mixes with cement type 1(C3S= 46.39 and C3S/C2S = 1.78) shows more resistance to Es than mixes with cement type 2 (C3S= 61.22 and C3S/C2S =4.44). The SCC mixes containing 10% SF as replacement of cement shows more resistance to external sulfate attack. The percentage of increase is 17.95% for SCC mixes with type 1 cement and W/cm =0.3 and 17.88% for SCC mixes with type 2 cement and W/cm =0.3 compared to reference concrete mixes

A VHDL Model for Implementation of MD5 Hash Algorithm

Mohammed A. Noaman

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1107-1116

With the increase of the amount of data and users in the information systems, the requirement of data integrity is needed to be improved as well, so the work has become necessary independently. One important element in the information system is a key of authentication schemes, which is used as a message authentication code (MAC). One technique to produce a MAC is based on using a hash function and is referred to as a HMAC.MD5 represents one efficient algorithms for hashing the data, then, the purpose of implementation and used this algorithm is to give them some privacy in the application. Where they become independent work accessories as much as possible, but what is necessary, such as RAM and the pulse generator. Therefore, we focus on the application of VHDL for implement and computing to MD5 for data integrity checking method and to ensure that the data of an information system is in a correct state. The implementation of MD5 algorithm by using Xilinx-spartan-3A XCS1400AFPGA, with 50 MHz internal clock is helping for satisfies the above requirements.

Studying some of the Geotechnical Properties of Stabilized Iraqi Clayey Soils

Ishraq Khudhair Abass

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1117-1130

In many road construction projects, if weak soils exist, stabilization and improvement of their properties is necessary. The stabilization process aims at increasing the soil strength and reducing its permeability and compressibility. An experimental program was undertaken to study the effect of engineering properties of kaolin clayey soils ((the kaolin was supplied by the General Company of Geological Survey and Mining which originally obtains from Al-Dewiekhla near Aukashat district in the west of Iraq)) when blended with lime (L) and Silica Fume (SF). A series of laboratory experiments have been implemented for varieties of samples: 2.5%, 5.0%, 7.5% and 10.0% for (Lime) and 2.0%, 4.0% and 6.0% for(Silica Fume). These experiments are: consistency limits test, specific gravity test, compaction test, unconfined compression test and California bearing ratio test. For each test, the optimal quantity of Lime (L) and the optimal percentage of Lime Silica Fume (LSF) combination were determined. The results revealed that: the optimal percentage of LSF combination was attained at a (2.5%L+6.0%SF), which served as control in this study. This optimal percentage: decrease the liquid limit, plasticity index, specific gravity and maximum dry density; and raise the optimum moisture content, unconfined compressive strength and California bearing ratio. These results showed also, that the combination of LSF stabilization at (2.5% L+6.0% SF) is better than the optimal one which achieved by Lime alone: 2.5%L for plasticity index, 10.0%L for specific gravity, maximum dry density and optimum moisture content, 5.0%L for unconfined compression stress and 7.5%forCaliforniabearingratio. All of these results indicated that the engineering properties of clayey soils can be enhanced, by blending Lime and Silica Fume together.

Evaluation of Acoustics Insulation and Thermal Conductivity through Walls in Building

Haqi Ismael Qatta

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1131-1150

Anew type of porous clay bricks is proposed , this research studies the effect of adding industrial wastes admixtures with different percentages on the thermal and acoustics insulation properties of clay bricks . Different types of admixtures were used in this work ,including plastic cuttings ,wood saw dust ,palm fiber with ( 5% ,10% ,15% ,20 ) percent of weight of each one . Acoustics insulation , thermal conductivity ,specific heat capacity ,porosity and variation of density have been examined for each samples at all percent of admixtures and comparing with the reference clay bricks samples . Form the obtained test result show the admixtures effect on the properties of clay bricks , the best material which can used from this paper is palm fiber to get the best properties of acoustic insulation , thermal conductivity and density for 20% admixtures percentage comparing with the standard bricks .

Comparative Investigation of Friction StirWelding and Tungsten Inert on Gas of 6061T651 Aluminum Alloy Mechanical Property and Microstructure

Samer Jasim Mahmood

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1151-1165

This study has been conducted to investigate the effect of welding process parameter on the mechanical properties and microstructure of aluminum alloy 6061, using friction stir welding (FSW) and Tungsten inert gas welding (TIG). Different friction stir welded specimens were produced by employing variable welding speed from 10 to 40 mm/min, and constant rotation speed at 900 rpm. Different mechanical tests and microstructure examination were performing to evaluate the joints. The experimental results indicate that the welding process parameters have significant effect on mechanical properties of the joints, the best result of the (FSW) weld achieve at 30 mm/min welding speed which give tensile strength 189 MPa, and 55% joint efficiency of the ultimate tensile strength of parent metal. Tungsten inert gas welded (TIG) give tensile strength 124 MPa with 37% efficiency of the ultimate tensile strength of parent metal. The profile of micro hardness tests is shown variation in the hardness through the welding zones the lowest value at heat affected zone which is 60 HB and the highest value at the nugget zone which is 80HB, but in the case of Tungsten inert gas welded (TIG) the micro hardness profile is constant though the welded zones and the value of the hardness is very low about 43. The microstructure examinations of the friction stir – welded (FSW) are shown three welded zones, first fine equated crystalline in the nugget zone, second highly elongated grain with very small cells in thermo mechanical affected zone and third slightly elongated coarse grain in heat affected zone. For Tungsten inert gas welding (TIG) the microstructure contain dendrite structure with black eutectic regions and significant amount of aluminum and silicon.

Multi-Stages for Tuning Fuzzy Logic Controller (FLC) Using Genetic Algorithm (GA)

Ammar G. Samir

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1166-1181

In this paper, a study on tuning of fuzzy logic controller (FLC) using genetic algorithm (GA) for controlling an armature controlled DC motor as an example of linear plant and for controlling nonlinear plant as another example is performed. There are different ways in which a FLC can be tuned, like: tuning the scaling gains, Rule Base (RB), and Data Base (DB) represented by type of membership functions or parameters of membership functions used. The tuning process in this paper includes a multi-stage tuning represented by searching the good scaling gains, RB, and DB then a combination of multi-stage (CMS) tuning methods using Genetic Algorithm (GA) based on a fitness function that is defined in terms of performance criterion (Integral of Squared Error ISE). The performances of these tuning stages are evaluated and a comparison between them has been introduced using linear and nonlinear plants.

The Effect of Different Operating Parameters on the Corrosion Rate of Carbon Steel in Petroleum Fractions

Nagham Salman Hassan

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1182-1193

The corrosion in petroleum pipelines was investigated by the studying the corrosion of carbon steel in crude oil and refined petroleum products which include gasoline, kerosene, and gas oil. Weight loss method was used in which test specimens of carbon steel, with a known weights, were immersed in the test media for a total exposure time of 60 days. The weight loss was measured at an interval of 10 days and the corrosion rate was determined. The results showed that corrosion rate are highest for gasoline followed by kerosene, gas oil and crude oil, in a decreasing order. The observed pattern in the corrosion behavior is consistent with the density and weight percent of hydrogen in the hydrocarbon products. The corrosion rate increases with decreasing density and increasing weight percent of hydrogen. Experiments were carried out at different temperatures (30, 60, 90 and 120oC) at a constant partial pressure of CO2 (50psi) in 3.5% NaCl solution. The results indicated that as partial pressure of CO2 and temperature increase, corrosion rate increases due to due to continuous dissolution of iron ion and formation of weak carbonic acid. The weak carbonic acid dissociates into carbonate and hydrogen ion, which increases the cathodic reaction on the metal surface.The presence of small amount of H2S (0.4 ppm) increases the corrosion rate significantly.

Experimental Investigation of Minimum Fluidization Velocity in Three Phase Inverse Fluidized Bed System

Khawla A. Ali; Ali Huseein Jawad; Sarmad I. Ibrahim

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1194-1203

Minimum fluidization velocity is one of the most important parameters when characterizing the hydrodynamics of a fluidized bed. Experiment studies on the effects of bed height and material density on the minimum fluidization velocity for inverse fluidization beds. Were carried out using a 10 cm diameter cylinder fluidized bed. Two types of particles were tested polyethylene (PE) and polypropylene (PP) bead, each with a density of 966.6, 877.3, 896.4, or 846.2 kg/m3, respectively, Results show that minimum fluidization velocity for tow tested materials was insensitive to bed height and increased with increasing the material density. The minimum fluidization velocity was correlated with dimensionless groups and independent parameters with correlation coefficient is 0.9389.

Design and Implementation of an Interface Circuit for DC Motor Speed Control Using the PWM Technique

Firas Mohammed Ali Al-Raie

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1204-1212

In this paper an electronic interface circuit for controlling the speed of a small permanent magnet DC motor with the aid of a personal computer (PC) has been designed and implemented. The basic operation of the proposed circuit is based on the pulse width modulation (PWM) using a pulse generator with variable pulse width to drive the motor circuit. The ON and OFF time periods of the PWM signal are changed by means of mechanical relays connected to the pulse generator circuit. These relays are connected at the same time to the parallel port of the PC via a buffer and a driver. A computer program written in C++ programming language was used to generate the proper digital sequence needed to drive the control circuit in three different speed levels. This circuit was thereafter implemented and tested successfully.

Computation of Energy Distribution as A Function of Wave-Vector (K) for Specifi c CNT Configuration

Hiba Hassan

Engineering and Technology Journal, 2013, Volume 31, Issue 6, Pages 1213-1220

In this paper, the energy dispersion relation has been calculated for certain configuration of single wall carbon nanotubes (SWNT) with respect to the wave vector (k). The three types of SWNT are armchair, zigzag, and chiral, so the energy dispersion relation for them are calculated for different chiral vectors. Taking two chiral vectors for each type of CNT, so (7, 7), (10, 0) for armchair, for zigzag (7, 0), (10, 0), and (10,5), (20,5) for chiral .