Print ISSN: 1681-6900

Online ISSN: 2412-0758

Issue 3,

Issue 3


Three Dimensional Simulation of Supersonic Flow over Missiles of Different Shapes

Jalal M. Jalil; Hussain H. Al-Kayiem; Ahmed Kadhim Hussein

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 325-343

In this work, a three-dimensional primitive variable of supersonic flow over
missiles was computed based on finite difference computational fluid dynamic
methods. The problem was considered is to deal with external, inviscid, compressible
supersonic- flow over three-dimensional missiles with and without canard. Euler
equations were solved using time-marching MacCormack’s explicit technique. The
flow conditions are taken at sea level and Mach number was tested up to 4.0. To deal
with complex shape of missiles the so-called “body fitted coordinate system” was
considered and the algebraic and elliptic methods were used to generate grids over
missiles. The number of iterations and the number of mesh points depending on
Mach number. The result indicate, that for the same Mach number, the increasing of
mesh points, lead to increase of the number of iterations

Removal of Iron (II) from Wastewater by Locally Prepared of Activated Carbon

Luma H. Mohmoud

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 344-353

The use of low-cost activated carbon derived from reed, an agricultured waste material,
has been investigated for the removed of Fe (II) from wastewater, using batch method. The
influences of the weight of adsorbent (0.2-2) g, pH of solution (1-9) and initial Fe(II)
concentration (10-80) mg/l have been studied. The suitability of the activated carbon used
was tested by fitting the adsorption data with Langmuir and Freundlich isotherms. The
study showed that the adsorption data obtained are obey the Freundlich isotherm fitting.

Study of Some Physical Behavior for Polycarbonate In Two Different Solvents at Room Temperature

Khalid Mershed E; Raouf Mahmood Raouf; Harith Hasoon Jasim

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 354-363

The goal of this research was to study some Rheological and optical properties of
poly carbonate in (chloroform and toluene) with different concentrations to know the
physical behavior of this polymer in two solvents at room temperature.It was
determined that the value of polymer solution in these two solvents with different
concentrations and the optical absorption, average viscosity molecular weight
Effective molecular radius. The results have shown that the values of density, (shear,
relative, specific, reduced, original) viscosities, Effective molecular radius and
average viscosity molecular weight, increase with poly carbonate concentration in
two solvents.The results also showed that prepared concentrations density was
significantly influenced by the density of solvents used; this influence was not in the
same magnitude for the rest of measurements and calculations. This may be due to
the dynamic behavior of the polymer in a solvent.

A Fuzzy Interface System to Predict Ultimate Strength of Circular Concrete Filled Steel Tubular Columns

Kadhim Zuboon Nasser

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 364-377

In this study, a model for predicting the ultimate strength of circular concrete
filled steel tubular columns (CCFST) under axial loads has been developed using
fuzzy inference system (FIS). The available experimental results for (129) specimens
obtained from open literature were used to build the proposed model. The predicted
strengths obtained from the proposed FIS model were compared with the
experimental values and with unfactored design strengths predicted using the design
procedure specified in the AISC 2005 and Eurocode 4 for CCFST columns. Results
showed that the predicted values by the proposed FIS model were very close to the
experimental values and were more accurate than the AISC 2005 and Eurocode 4
values. As a result, FIS provided an efficient alternative method in predicting the
ultimate strength of CCFST columns.

Excitation Control of Synchronous Generator Via Neural Network Based Controllers

Ekhlas M. Thajeel

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 378-397

Modern power systems are complex and non-linear and their operating can vary
over a wide range. This paper presents a linear mathematical model of the
synchronous generator to control the excitation system based on Neural Network to
simulate an Automatic Voltage Regulator. The voltage regulator is used to modify
terminal voltage for the purpose of tracking a reference voltage and comparative with
PID controller. ANN (NARMA-L2) system is proposed as an effective controller
model to achieve the desired enhancement. This model after training can be called as
(Identifier).The proposed technique is evaluated on a single machine infinite bus
under different operating conditions (no-load and full load condition) by using
MATLAB simulink software.

Experimental and Numeriacal Study of Moisture Moviment Inside an Air Conditioned Space

Wahid S. Mohammad; Omar M. Mohamme

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 398-415

This research is concerned with a computational study to simulate a turbulent three
–dimensional buoyancy recirculation flow in an air-conditioned space. The study
includes the simulation of heat and moisture generated from an internal source inside the
space. An experimental facility to study temperature and moisture distribution in an airconditioned
space has also been designed, constructed and tested in a laboratory scale. A
numerical procedure was carried out to solve the elliptic partial differential equations that
govern the flow, heat and mass transfer in a finite –volume form. The finite -volume
approach was applied to solve these equations using the upwind –differencing scheme.
The SIMPLE iterative procedure [1] for solving the algebraic equations is employed in
the present study. The proposed method is the line by line technique uses the Tri-
Diagonal Matrix Algorithm (TDMA) as its basic unit. A modified version of a threedimensional
elliptic computer code was used to simulate heat and moisture transfer
generated from the internal source inside the space. A study of the flow, heat and mass
transfer in air-conditioned space are used as test cases to justify the performance of the
computational procedure. The temperature and moisture distribution were compared with
predictions of previous researchers. The data from the experimental model was also used
to verify the computational procedure predictions.

Influence of Substrate Temperature on Structure and Optical Properties of CdO Thin Films Prepared By Pulsed Laser Deposition

Muhanad Adel; Khaled Z.Yahya

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 416-425

Nanocrystallites of cadmium oxide (CdO) thin films were deposited by pulsed laser
deposition technique on glass substrates using Nd:YAG laser at 532nm wave length.
X-ray diffraction (XRD) patterns confirmed the nanocrystalline cubic CdO phase
formation. The intensity of XRD peaks increases with the increase in substrate
temperature and better crystallinity takes place at higher temperature. The
morphology of deposited films were characterized by scanning electron microscope
(SEM) and atomic force microscope (AFM); with increasing substrate temperature,
both the grain size and surface roughness increase .The grain size value (12,18,47
nm) and rms roughness values were 63.3, 98.8 and 138.4 nm for thin films deposited
at 100 , 200 and 300ºC respectively. UV–Vis spectrophotometric measurement
showed high transparency (nearly 88 % in the wavelength range 500–900 nm) of the
CdO thin film with a direct allowed band gap value lying in the range 2.81–3.7eV

Shock Wave Capturing Numerically in Two Dimensional Supersonic Wind Tunnel for Different Configuration

Ahmed Fouad Mahdi

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 426-442

Numerical solutions of two dimensional Euler equations are obtained for
transonic and supersonic flows. The shock capturing method is employed to solve
compressible Euler equations by using MacCormack's time marching method that
an explicit finite-difference technique. The test case chosen is that of a transonic
and supersonic flow through a channel with a circular arc bump on the lower wall,
half wedge and extended compression corner. Computational results accurately
reproduced the flow field. In three cases, contour plots showing the important
features of the flow-field are presented. The algorithm is tested for steady-state
inviscid flows at different Mach numbers ranging from the transonic to the supersonic
regime and the results are compared with the existing numerical solutions. The
method incorporates bounded high resolution of discontinuities and is therefore well
suited to all flow regimes ranging from transonic to supersonic.

Modification of Diffie–Hellman Key Exchange Algorithm for Zero Knowledge Proof

Mahmood Khalel Ibrahim

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 443-453

Networks and entity groupings requires entity authentication while preserving the
privacy of the entity being authenticated. Zero-Knowledge Proof (ZKP) plays an
important role in authentication without revealing secret information. Diffie–Hellman
(D-H) key exchange algorithm was developed to exchange secret keys through
unprotected channels. This paper discusses zero-knowledge protocols and Diffie–
Hellman algorithm and analyzes their vulnerability against known attacks. Also it
presents a proposed protocol based on modification of Diffie–Hellman algorithm into
an interactive zero-knowledge proof protocol. The proposed protocol is designed and
developed to satisfy the zero-knowledge proof properties and resists the known attacks

Fuzzy-Swarm Controller for Automatic Voltage Regulator of Synchronous Generator

Abdulrahim Thiab Humod; Wisam Najm Al-Din Abed

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 454-473

The main objective of this work is to propose Artificial Intelligence (AI) controller
to enhance the performance of Automatic Voltage Regulator (AVR) of
a Synchronous Generator (SG) during different loading conditions. The proposed
mathematical model of the SG with saturation nonlinearities is connected to different
loads in two ways. The first each load is connected individually and the second the
SG loads change during the operation to ensure the robustness of controller for wide
load variations. Two types of controllers are used. The first controller is the
Proportional-Integral (PI) based on Particle Swarm Optimization (PSO) technique to
obtain optimal gains. The second controller is Fuzzy PD+I with gains and
Membership Functions (MFs) tuned by PSO technique. The results show the
improvement of PI-PSO performance on conventional PI controller; also show the
improvement in the performance of Fuzzy PD+I using PSO technique on PI-PSO.
The simulation of SG is performed using MATLAB program version 7.10.0.499
(R2010a).

LDPC Error Floor Improvement

Aseel Hameed Majeed

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 474-488

The error-correcting performance of low-density parity check (LDPC) codes, when
decoded using practical iterative decoding algorithms, is known to be close to
Shannon limits. In this paper we study the LDPC codes performance when varying
code rate, constellation level and the maximum number of iteration, this paper shows
better coding gain can be obtained at the cost of higher complexity or higher bit rate.
For some cases, due to their inability to reach very low bit error rates (e.g., 10− 12) at
low signal-to-noise ratios (SNRs), a consequence the error rate floor phenomenon
associated with iterative LDPC decoders is produced. This paper demonstrates that
the concatenation system used LDPC as an inner code and the Bose, Chaudhuri, and
Hocquenghem codes (BCH) as an outer code can successfully lower the floor.
Connecting BCH codes lower the LDPC BER floor by a factor( from 32 to 22) at
about SNR (from -1dB to 1.8 dB) with the same overall cod rate(i.e without any
reduction in the bandwith efficiency) and restricted few number of iteration ( only 5
iterations).

Experimental Study on Boiler Scales Cleaning Using Hydrochloric and Citric Acids

Dina Raheem; Janet Lazer

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 489-499

The effect of hydrochloric acid and citric acid was studied experimentally for
boiler chemical cleaning to determine the dissolved scale by using carbon steel
samples of water-side boiler tubes sections ,different concentrations of hydrochloric
acid HCL and citric acid were used
(2%,3%,4% and 5%) to calculate the weight loss of samples then determined the
dissolved scale in gm/m2. The more efficient acid for the chemical cleaning, was
found to be HCL acid at 5% concentration by using 0.3% rodin inhibitor at temp.
60 and time 30 minute to obtain 248 gm/m2 of dissolved scale while the citric
acid at 5% concentration by using 0.3% hexamine inhibitor and temp.70 and
time 240 minute to obtain 168 gm/m2 of scale dissolved.

Evaluation of Crude Anthrax Protective Antigen as an Adjutant For Brucella Abortus Vaccine In Mice

Inam Jasim Lafta

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 500-511

Anthrax crude protective antigen (PA) was used in this study as an adjutant
with Brucella abortus S19 strain vaccine in a ratio of 1:1 to immunize mice in
dose of 0.1 ml s/c in order to decrease side effects of S19 vaccine and also to
enhance its immunogenicity. Three groups of mice were immunized with the
mixture (composed of anthrax PA +S19, S19 alone, and sterile PBS solution as
a control. They were compared concerning cellular and humeral immunity. The
group treated with the mixture was the best regarding skin test, the difference of
thickness was 1.51± 0.103 mm after 24 h and 1.14± 0.103 mm and 0.89± 0.100
mm after 48 and 72 h, respectively. As well as that group revealed the highest
antibody titer, which reported 0.7153± 0.08 nm as compared with 0.3743± 0.06
nm in S19 group. These findings were verified by studying the
histopathological changes.

Construction of Railway Track Using Asphalt – Ballast Layer

Kawther.Y.H.AL-Soudany

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 512-528

The work presented in this paper focuses on new trends in the construction of
rail track using asphalt ballast layer. Model tests were performed with ballast layer
150mm or 200mm. These thicknesses are the common range used in railway
construction. Overlaying a sandy layer 400mm in thickness. This condition
represents a case where rail networks pass through sandy zones.
Two series of model tests were performed; the first on untreated ballast and the
second where the ballast layer was incorporated with inter asphalt layers.
A model footing 200mm wide and 400mm long was placed on the surface of the
ballast layer and loaded monotonically or repeatedly up to failure. These
dimensions were selected representing the plain strain condition which exists in
real rail networks. The layers treated with asphalt demonstrated substantial
improvement in the load carrying capacity over the untreated layers.

Simulation Study and Comparison Green Freeze Technology Utilizing with Theory of Different Adsorption Working Pairs of Solar Adsorption Refrigeration

Faiza Mahdi Hadi

Engineering and Technology Journal, 2012, Volume 30, Issue 3, Pages 84-97

In this research a study of the theory of six different adsorption pairs to check
and choose the best adsorption pair in terms of adsorption capacity and the effect of
high and low temperature on it. It has been shown that the best adsorption pair at
the temperature 25oC is the activated carbon fiber with methanol (ACF +
CH3OH). Where the adsorption capacity is = 0.45 ACF x , followed by granules
of activated carbon with methanol (AC + CH3OH) and adsorption capacity is
= 0.3 AC x by more than half compared to a pair of activated carbon fibers. Then,
four adsorption pairs have been selected for solar adsorption ice maker system and
a couple for solar adsorption chiller system. The application of Excel has been used
to solve governing equations and mathematical model of thermal balance
simulation the largest amount of ice produced, the highest coefficient of
performance for all pairs adsorption mentioned at the best operational temperature,
it was found that the activated carbon fiber with methanol, the largest amount of
ice produced 2.55kg and the highest coefficient of performance of 0.38 in the
adsorption ice maker at operating temperature of generator is (110oC). The
Adsorption chiller for a couple, silica gel with water, the best in terms of impact
with the cooling effect and coefficient of performance of the highest at temperature
range of (64 -110oC).