Al-Nahrain Journal for Engineering Sciences

This paper presents a mixed transform
based speech denoising technique obtained by the
combination of multicircularlet and slantlet
transforms and thresholding algorithm. It is well
known that denoising is a compromise between the
removal of the largest possible amount of noise and
the preservation of signal integrity. Mixed
transform is an intelligent tool for solving speech
processing problems such as speech denoising , the
general algorithm of speech denoising using
discrete wavelet transform (DWT) is presented,
followed by the proposed general algorithm of
speech denoising using mixed transform. This
paper also discusses the effect of using DWT and
mixed transform in speech denoising,
theirperformances in terms of mean square error
(MSE) and peak signal to noise ratio (PSNR) are
assessed. Computer simulation results indicate that
the mixed transform offers better MSE and PSNR
than DWT.

In this study, the effect of support values on
the natural frequency and critical flow velocity
of a straight pipe conveying laminar flowing
fluid is studied. The aim of this work is
deriving a new analytical model to perform a
general study to investigate the dynamic
behavior of a pipe under general boundary
conditions by considering the supports as
compliant material with linear and rotational
springs. This model describes both the
classical (simply support, free, built, guide)
and the restrained boundary condition and it is
not required to derive a new frequency
equation if the boundary conditions is changed
,also the result will be near to reality by
knowing the physical parameters for the
compliant material and the pipe.

An experimental and numerical study was carried
out to investigate heat transfer and flow
characteristics through the tractor heat exchanger
(radiator). The engine of the tractor is Diesel
(compression ignition) engine type. The
experimental study used heat exchanger (radiator)
manufactured from copper instead of the original
heat exchanger of the tractor, which is
manufactured from iron. Both heat exchangers
consist of circular cross sectional tubes and plate
fins. The temperatures was measured inside the
cooling room of engine for both cases at the same
time and the same loads. The results of the
experimental investigation showed that the heat
exchanger is manufactured from copper provided
temperatures less than the heat exchanger
manufactured from iron, that means heat rejected
by copper heat exchanger is more than heat
rejected by iron heat exchanger. The use of copper
heat exchanger is better than iron heat exchanger
for cooling the tractor engine. In the numerical
study used model of copper heat exchanger to
analyzed by CFD method at different air velocity
from (0.5 m/sec) to (7 m/sec) for laminar air flow.
The object of this study was enhancement the heat
transfer process from the cooling fluid of heat
exchanger. The results of the numerical study
shows that heat transfer rate increase with
increasing air flow during heat exchanger
(radiator). Good agreement between experimental
and numerical results is obtained.

The intrinsic viscosity has been studied for
several polymers which are used in some
industrial applications, such as polyisobutylene of
types Oppanol B150, 200, and 250 with different
molecular weights of 2.5, 4.1 and 5.9 million
g/mole, respectively, which dissolved in crude
and gas oil. In addition three types of additives
brought from Al-Dura refinery, olefin copolymer
(OCP), {viscoples-4-677, viscoplex-215496, and
Lubrizol R 7077} which dissolved in crude oil,
and the polymers which is soluble in water such
as polyacrylamide with high molecular weight
and xanthan gum with molecular weight 3.7
million g/mole where also studied. It was found
that the intrinsic viscosity of polyisobutylene
decrease as the temperature increase in crude and
gas oil. The olefin copolymer (Viscoplex-4-677)
showed the same behavior as polyisobutylene
where it can be used as drag reduction agent. It
was noted that neutral polymers as well as
polyelectrolytes could be used as drag reduction
agent.

The aim of this research is to study the factors
affecting the settling velocity (V S ) in Non-
Newtonian fluids which are the rheological
properties, concentrations of non-Newtonian fluids,
particle shape and size.
An experimental apparatus was designed
and built, which consists of Perspex pipe of length of
160 cm. and inside diameter of 7.8 cm. to calculate
the settling velocity, also electronic circuit was
designed to calculate the falling time of particles
through fluid.
Two types of solid particles were used;
glass spheres and crushed rocks as irregularly shaped
particles with different diameters and compared with
each other. The concept of equivalent spherical
diameter (D S ) was used to calculate the diameters of
irregularly shaped particles.
The settling velocity was calculated for
Non-Newtonian fluids which represented by Power-
Law fluid. Two types of polymers were used,
Carboxy Methyl Cellulose with concentrations of
(3.71, 5, 15 and 17.5) g/l and polyacrylamide with
concentrations of (2, 4 and 6) g/l.
The results showed that the settling velocity
decreased when fluid becomes far from Newtonian
behavior (flow index n decreased) and also when
concentrations of polymer solutions increased, also,
the settling velocity increased with particle diameter
or volume.
Three sets of equations were concluded; the
first relates settling velocity with flow index (n), the
second relates settling velocity with concentrations,
and the third relates settling velocity with particle
diameter.

Heat transfer enhancement by wire coils is adopted in order to increase the thermal performance of a double pipe heat exchanger. The heat exchanger adopted is 1245 mm effective length, 28 mm outer diameter and changeable inner diameter (11 or 14 mm). Wire coils of e = 1 mm and p = 10, 20, 30 and 40 mm are used as turbulence promoters to augment heart transfer inside the inner tube at a Reynolds number range of 5000 to 40000. Water is used as the working fluid in the two sides. Variation in the experimental conditions is attained by changing the mass flowrates of unenhanced side and changing the inlet temperature of hot fluid. These conditions are followed in order to have as large amount of data points as possible in addition to observe the effect of changing these conditions. Heat transfer is increased inside the inner tube by 2.43 folds, as compared to empty tube at the same Reynolds number accompanied by friction factor increase of 4.75 folds. New correlations of Nusselt number and friction factor for the enhanced tubes are proposed as functions of Reynolds number, Prandtl number and the geometrical characteristics of inserts and tube sizes.

A radioactive liquid waste contaminated with cesium-137 was found underneath a destructed radioactive waste treatment station in Tuwaytha site 25 km south of Baghdad - Iraq.
The appropriate sorbent materials found for the removal of radio cesium-137 were bentonite and modified bentonite with corresponding removal efficiencies of 85% and 91.8% respectively. The favorable batch experimental conditions were found to be 800 rpm stirring speed, 200 mg sorbent mass, 45μm sorbent particle size, and solution temperature of 30 oC for an initial radio cesium concentration of 0.44 mg/l.
The BET isotherm model was found to represent the experimental results very well.

A new control design procedure has been proposed in this paper based on the LQG control design. A two degree of freedom controller with integral action is obtained and tested on the magnetic levitation system, which is a good test-bed for control design because of its nonlinearity and unstability with practical uses in high-speed transportation and magnetic bearings. Simulations are performed under MATLAB environment and included to highlight that the proposed controller accurately achieves position tracking for different kinds of reference inputs.

The main contribution of this paper to describes and implements the Castella tracking system (CTS) in high volume Field Programmable Gate Arrays (FPGA) devices, which presents the complete design of an adaptive two-state Kalman tracking filter that is suggested by Castella to track the maneuvering and nonmaneuvering targets using FPGA. The basic design for this system required a very high cost lie out of range of FPGA capacity. This paper will present a novel approach to reduce the cost of this system. The new method depends on the reduction of the width of data bus of the system without reduction the accuracy of the system. However the novel approach will reduce the cost to about 10% from the original cost to implement the system in a single chip FPGA. Finally, two simulation scenarios are also given to illustrate the efficiency of this adaptive filter comparing with the conventional Kalman filter.

In this paper, the behavior of Wavelet Packet-Orthogonal Frequency Division Multiplexing (WP-OFDM) system based on Genetic Algorithm (GA) to mitigate both the Inter-Symbol Interference (ISI) created by a channel with longer impulse response duration than that of the Cyclic Prefix (CP)as well as the Inter-Carrier Interference (ICI) resulting from high Doppler spreads is investigated. This is realized by simulation environment to utilize the advantages of modeling programs. In this simulation, Wavelet Transforms (WT) have been considered as alternative platforms for replacing Inverse Forrier Transform (IFFT) and FFT; all are programmed using MATLAB package. The simulation result shows that the ICI (ISI) power is significantly reduced. In this investigation, the effect of delay spread with 16-QAM and QPSK modulation schemes was studied. Results also show that our model, genetic based WP-OFDM, is superior as compared to WP-OFDM.

The aim of this work is to produces a technology of recognition and identifies of the person by using the iris. The work was started by reading the images of eyes (UBIRIS database). After that, the iris region localized from the eye image by using the method of image processing. The iris shape is circular so it transfer to rectangular shape and enhance the image and remove the noise like eyelashes and flash of the camera. Then the image quantized from 256 grey levels to 16 grey levels. Four statistical functions used because these functions give us accurate description of iris, the samples had been taken in four angles. The information for each sample is save in database. The last stage is to classify the samples by using neural network. The results will prove that the work have high accurate conclusions.

This work presents a design of secured Wireless Network by utilizing Virtual Private Network (VPN) technique and provides a solution to enhance its performance by using Wireless Quality of Service technique (WQoS).A set of parameter are investigated include delay, throughput, jitter round trip time. These parameters are checked for a WLAN without VPN and WQoS, WLAN with VPN, and WLAN with VPN and WQoS.

In this research a biological model was modified upon a homomorphic sccadic eye movement model by adding and calculating the mass of eye and the elasticity of eye tendon and take a primary position only. According to this modification, equation with six order was appeared which was processed with a MATLAB SIMULINK to get a desire results of theta, velocity and acceleration in the normal case.
For the same model, a disease was estimated to evaluate the results of theta and how it is affected by this disease which was estimate the increase and decrease happened in the primary elastic element and viscosity. After theta controller was added to the model to control the system and get the desire angle which is equal to 15º in the normal case while in the system with disease, the PI controller that used can control only the system during normal case while in the system with disease, the PI controller could not control the system to get the desired angle.