ISSN: 2521-9154

Volume 14, Issue 1

Volume 14, Issue 1, Spring 2011, Page 1-108


Time-Dependent Behavior of Excavation in Cohesive Soils Using the Bounding Surface Model

Dr. Qassun S. Mohammed Shafiqu

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 1-12

The study was to investigate the behavior of excavation in cohesive soils using the bounding surface model. The model and the finite element formulation are described and verified. Then the ground movements were predicted around an excavation in several types of cohesive soils. The results of the analysis demonstrate the effects of the consolidation process and permeability on the stability of the excavation and that the displacements at excavation boundaries increase with increasing permeability and time but at a lower rate as the permeability value decreased. Also the study shows a significant influence of the critical state parameters on the behavior of excavation in normally consolidated clay comparing with the surface configuration and hardening parameters of the model. Thus the modified Cam-clay model which employs a lower number of parameters can be used for the problems of excavation in normally consolidated clay.

Adding Polymer to Mortar Mixture According to the Procedure Recommended by ASTM C 1439

Zainab M. I. Kammouna

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 13-18

Polymers are considered one of the admixture kinds which they are used to improve the quality and the performance of mortar and concrete. In this study the Styrene Butadiene Rubber (SBR) was used as a polymer to see its effects on the mortar. The (SBR) is considered as a water resistance polymer and bonding agent.
Four cement mortar mixes were made in this study, the first one was considered as a reference mix which is not include (SBR) while the other mixes were included (SBR) in deferent percentages. The (SBR) was added as a percentage of cement weight. The amount of mixing water was varied to achieve the same flow which was accomplished in the reference mix throughout carrying out flow table test. Flow table test was adopted according to ASTM C 1439-99 (1) recommendations.
For each mix, two prisms were prepared to carry out the drying shrinkage test, nine cubes for the compressive strength test and three cubes for the total water absorption test.
It was found that when the quantity of (SBR) increases, the physical properties of mortar under study (drying shrinkage, compressive strength and total water absorption) deteriorate which is adverse to the proposal of advantages due to adding (SBR). This result leads to that the recommendation of ASTM C 1439-99 (1) that adopt the flow table as criteria of adjusting the amount of adding water accompanying with deferent percentages of (SBR) is not adequate

Damaging Effect of Static and Moving Armoured Vehicles with Rubber Tires on Flexible Pavement

Dr. Saud A. Sultan

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 19-33

The damaging effect of military armoured vehicles with rubber tires on flexible pavements was studied. Two types of military armoured vehicles with rubber tires were considered, namely CM32 four-axle and CM32 triple-axle. A measure of the damaging effect of military armoured vehicles with rubber tires loads was achieved by correlating their equivalent loads with the AASHTO equivalency factors. The equivalent load was developed on the basis of mechanistic - empirical approach. It was found that the damaging effect of the studied loads of CM32 four-axle military armoured vehicle with rubber tires is 0.262-2.853 times the damaging effect of the standard 18 kips (80 kN) axle load depending on the thickness of asphalt layer. It was found that the damaging effect of the studied loads of CM32 triple-axle military armoured vehicle with rubber tires is 0.933-4.880 times the damaging effect of the standard 18 kips (80 kN) axle load depending on the thickness of asphalt layer. It was found that the damaging effect of the braking forces of CM32 four-axle military armoured vehicle with rubber tires is 40 times the damaging effect of the CM32 four-axle military armoured vehicle weight only. It was found that the damaging effect of the braking forces of CM32 triple-axle military armoured vehicle with rubber tires is 5 times the damaging effect of the CM32 triple-axle military armoured vehicle weight only.

Spoken Word Recognition Using Slantlet Transform and Dynamic Time Warping

Sadiq J. Abou-Loukh

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 34-45

Speech recognition system has been widely used by many researchers using different methods to fulfill a fast and accurate system. Speech signal recognition is a typical classification problem, which generally includes two main parts: feature extraction and classification. In this work, three feature extraction methods, namely SLT, DWT Db1 and DWT Db4, were compared. The dynamic time warping (DTW) algorithm is used for recognition. Twenty three Arabic words were recorded fifteen different times in a studio by one speaker to form a database. The proposed system was evaluated using this database. The result shows recognition accuracy of 93.04%, 92.17% and 94.78% using DWT Db1, DWT Db4 and SLT respectively.

Performance Comparison of Two Estimators for Two-Phase Permanent Magnet Synchronous Motor

Dr. Amjad J. Humaidi

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 46-60

This paper presents and compares the performance of two Kalman filter schemes, the discrete extended Kalman filter (EKF) and unscented Kalman filter (UKF) for estimating the states (winding currents, rotor speed and rotor angular position) of two-phase Permanent Magnet Synchronous Motor (PMSM). Estimating the states of the system is performed by propagating the mean and covariance of the state distribution. For linear systems, the general recursive Kalman filter algorithm based on MMSE (minimum mean squared error) is the straightforward estimation technique to be implemented. For nonlinear systems, extended Kalman filter (EKF) is considered to be the best nonlinear estimator. The EKF is based on linearizing the state and output equations at every sampling instant. Therefore, this estimator requires continuously computation of the Jacobian matrix. The unscented Kalman filter (UKF) is based on implementation of the unscented transformation (UT) to the nonlinear state distribution (motor model). The UT uses the intuition that it is easier to approximate a probability distribution than it is to approximate an arbitrary nonlinear function or transformation. Apply this intuition to motor model, a set or cloud of points are generated around each state of motor model with specified sample mean and sample covariance. The nonlinear function (PMSM model) is applied to each of these points in turn to yield a transformed sample, and the predicted mean and covariance are calculated from the transformed sample. Based on predicted mean and covariance the UKF recursive algorithm can be developed. The performance comparisons are based on standard deviation estimation errors of both

estimators and the time computation effort required execute the algorithms of both filters. The simulated results show that the UKF gives best estimates at motor low speed, while its estimation performance degrade at high motor speed. On the other hand, the EKF shows bad estimation characteristics at low frequency and it yields good estimates at high source frequency. However,, the EKF algorithm keeps lower time computation effort over wide range of rotor speed than that required to execute the UKF software for the same range of source frequency. The PMSM motor model and the algorithms of both filters are built in Matlab package using S-function capability and scalar control strategy are used to account for constant stator magnetizing flux.

Study the Effect of Cutting Conditions for turning process

Huda Hatem

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 61-66

Surfaces quality is one of the most specified customer requirements for machine parts. The major indication of surfaces quality on machined parts is surface roughness. The research aim is to study the cutting conditions and their effects on the surface roughness. This paper utilizes regression models to predict surface roughness over the machining time for variety of cutting conditions in turning. In the experimental part for turning, different types of materials (Aluminum alloy, Copper alloy, and Gray cast iron) were considered with different cutting speed (υ) and feed rate (ƒ).
A mathematical Model depending on statistical-mathematical method between surface roughness (Rz ) and cutting condition (υ , ƒ ) were derived, for the three materials.
The matrix of test conditions included cutting speeds of the 16, 30, 45 and 60 m/min, feed rates of 0.17, 0.35 and 0.7 mm/rev while the depth of cut has been kept constant. The effect of cutting parameters on surface roughness is evaluated and the optimum cutting condition for minimizing the surface roughness is determined. Mathematical model has been established between the cutting conditions and surface roughness using regression. The predicted values and measured values are fairly close, which indicates that the developed model can be effectively used to predict the surface roughness in the turning machining. As the results of this work, the mathematical models were used in predicting surface roughness, can be used in CAD-CAM manufacturing systems, this mathematical model helps engineer to reduce the efforts.
Mathematical models shows that the decreasing in the feed rate resulted in better surface roughness and increasing cutting speed resulted in better surface roughness. The goal of this work is to identify a relationship between experimental results and theoretical model, and study the proper process values for machining, to increasing the rates for raising the quality (better surface roughness).

Using Low-Density Parity-Check Codes to Reduce the Effect of Laser Line width For Optical Communication

Prof. Dr R. S. Fyath

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 67-79

The performance of coherent optical communication systems is degraded significantly by the phase noise of the semiconductor lasers. The phase noise is induced by spontaneous emission in the laser cavity and yields broadening in the laser linewidth. This paper addresses the application of the Low-Density Parity-Check (LDPC) codes as Forward Error Correcting (FEC) codes to relax the laser linewidth requirement. These codes are applied to three types of heterodyne optical receivers (BPSK, DPSK and QPSK) operating with finite laser linewidths.

Effect of Strained Quantum Wells of Enhanced Performance for Quantum Well Lasers in Direct Modulation

Dr. Mohammed Adnan Mahdi

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 80-87

Strained-layer quantum wells are interesting for applications in semiconductor lasers , because they allow both, a wider range of material combinations, and a certain amount of band structure and gain engineering. This layer is effected on frequency shift of the gain spectrum ,but gain increase also possible. The major advantages of strained quantum wells in the modulated quantum well lasers diodes are a very high modulation speed, a low frequency chirp (α-parameter) , a narrow line-width, and a low threshold carriers concentration. Strained quantum well lasers are better than the semiconductor lasers , which have a modulation band-width in upper teens and low twenties of gigahertz

Laser Based Measurement for Liquid Refractive Index

Ziad T. Al-Dahan

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 88-96

One of independent laser-based technique is presented to measure liquid refractive index, which is important in medical and other applications. Semiconductor laser diode of ≈ 630nm wavelength serves as alight source for measurement. Results are presented for different types of liquids in two methods, one of these methods is done by matlab
language as the theoretical result, the other method is the opti-cad program which represented the simulation results.
Good matching found between the two the theoretical and simulation results. The experimental setup is high precision, non-contact between the tools and the liquid which is under test.

The Effect of Laser Wavelength on Porous Silicon Formation Mechanisms

Narges Zamil Abdulzahra

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 97-101

In this work, the effects of coherent radiation (Laser) with different wavelength and photon energy during the electrochemical etching process on the structural characteristics PS samples were investigated. The porosity values were measured by depending on the microstructure analyses and gravimetric measurements. Surface morphology, layer thickness, pore diameter, pore shape, wall thickness and etching rate were studied by depending on Scanning electron-microscopic (SEM) images

Analytical Study of Water Purity Using Low Power He:Ne Laser

Mohammed F. Mohammed

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 102-108

In this research, an analytical study of water using laser source transport through some samples of water tubes was presented. He–Ne laser with measured maximum output power 2.83 mW was used to determine the purity of water by measuring its output power when it was passing through tube of water. This tube was initially filled by water and then by distill water contain different ratio of salts and clay. For each case, the output power would be measured and calculated its attenuation which was occurred when laser was passing through the water. The attenuation happened in the laser beam when transport through the water sample that contain NaCl due to the absorption process. The attenuation happened in the laser beam when transport through the water sample that contain clay due to the scattering process. Water tap mostly contain different ratio of salts and clay so the attenuation accurse in laser beam is due to absorption and scattering process, and it can be compared these results with that produce when mixing NaCl solution sample with the clay sample.

The effect of visual pollution resulting from change the

Shaymaa fadhel jassim

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 14, Issue 1, Pages 1-9

The research includes study the visual al pollution as a phenomenon spread in the large cities greatly, due to many factors as the fast technology development and misuse the structural planning in addition to wrong behaviors of environment's users, the matter which affect greatly in receiving the image at the recipient.
Then the visual pollution result from many factors such as signification marks especially trade marks of all its types, colors, shapes and volumes as well misdistribution the street furniture and garbage containers and random the buildings frontages in respect of finishing materials, disarrangement gaps and bulges between blocks, and cheating the design and alteration it as to the residential buildings in form leads to non agreement with design, regarding to the importance of residential buildings in our life, will concentrate the research on studying the visual pollution which result from alteration of the residents to the image of residential buildings randomly.
From review researches to be clear of existence a problem with regard to studying the visual pollution, and then finished it studying out of the role of signification marks especially trade marks and some of the street's furniture role; but it does not finish the study of visual pollution which result from change the residential buildings images, based on that, the aim of research it will be ( The effect of visual pollution resulting from the random change of the residential buildings images in receiving the image at recipient ).
The problem of research will be (non obviousness the role of visual pollution which result from change of the residential buildings frontages in receiving the image at recipient).
To solve the research's problem this matter will require the following: -

First: Putting words describe the visual pollution and the role of recipient.

Second: Doing a practical study includes choosing a residential assembler as a pattern to analysis it and choice a pattern of recipients to questionnaire them by using scale of variation of the indicative difference.

The research supposes that changing frontages of the residential buildings randomly by residents which not agree with the design leads to visual pollution, and the excess by this matter leads the frontage to loss its archetype, the matter which result from it confusion and disturbance in relation to the recipient which leads to un realization the image clearly and then pollution the environment and not interaction the recipient with it.