Journal of Engineering

1

DETERMINATION OF DEPTH OF PLACEMENT OF TUNNELS AND CAVITIES BY THE BOUNDARY ELEMENT METHOD

Omar Al-Farouk Al-Damluji, Mohammed Yousif Fattah, Rana A. J. Al-Adhamii

Pages: 53-70 English

Abstract

A boundary element numerical algorithm has been developed for the determination of stresses and deformations around cavities and tunnels. A study of the influence of depth below the ground surface on the distribution of stresses and deformations around cavities and tunnels is presented in this paper. The soil is assumed to behave linearly elastic. A computer program has been built to perform the numerical computations. The results show that with increasing the depth of placement of tunnel or opening below the ground surface, the settlements decrease. The maximum stresses occur at the haunches of the tunnel rather than at the crown. For the circular cavity that is considered in this paper, it was found that with increasing the depth below the ground surface (depth/tunnel diameter > 3), the surface settlements do not exceed 6 %from those obtained for the case of no-cavity condition.

Keywords

A boundary element numerical algorithm has been developed for the determination of stresses and deformations around cavities and tunnels. A study of the influence of depth below the ground surface on the distribution of stresses and deformations around cavities and tunnels is presented in this paper. The soil is assumed to behave linearly elastic. A computer program has been built to perform the numerical computations. The results show that with increasing the depth of placement of tunnel or opening below the ground surface it was found that with increasing the depth below the ground surface (depth/tunnel diameter > 3) the surface settlements do not exceed 6 %from those obtained for the case of no-cavity condition. the settlements decrease. The maximum stresses occur at the haunches of the tunnel rather than at the crown. For the circular cavity that is considered in this paper

2

Combined Convection Heat Transfer to Thermally Developing Flow in Horizontal Circular Cylinder

Yasin K. Salman, Hussain H. Ahmed, Hussein A. M

Pages: 1-15 English

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Abstract

Experiments were conducted to study the local and average heat transfer by mixed convection for hydrodynamically fully developed but thermally developing laminar air flow in a horizontal circular cylinder. The experimental setup used an aluminum cylinder with a 30 mm inside diameter and 900 mm heated length, subjected to a constant wall heat flux boundary condition. The investigation covers Reynolds number range from 400 to 1600 and heat flux varied from 60W/m² to 400W/m². Results present the temperature variation along the cylinder surface and the local and average Nusselt number variation with the dimensionless axial distance (Z).

Keywords

Combined Convection heat transfer Horizontal circular cylinder thermally developing flow

3

Free Vibration of Beam Elastically Restrained Against Translation and Rotation at Ends

Nabil H. H.

Pages: 17-24 English

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Abstract

This paper presents an approximate solution for the vibration of uniform and non-uniform beams with translational and rotational springs using the Rayleigh-Ritz approach. The frequencies are presented for a wide range of restrained parameters and compared with published literature, illustrating the accuracy and versatility of the approach. The results are useful for the design of beams, shafts, and piping under dynamic considerations

Keywords

Beam Elastic restraints Free vibration rotation Translation

4

TWO-DIMENSIONAL NUMERICAL MODEL FOR THERMAL POLLUTION OF SINGEL SOURCE IN RIVER

Rafa H. Al-Suhaili, Mohsin Jasim Nasir

Pages: 25-35 English

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Abstract

This research aims to apply a numerical model to describe thermal pollution in rivers. A two-dimensional numerical model was used to estimate temperature distribution in a river subjected to thermal pollution from a single source. The model incorporates the momentum conservation equation, thermal energy equation, and (k-e) turbulence model. The equations were solved using the Alternative Direction Implicit-Explicit (ADI) method with upwinding technique and Gauss-Elimination method. Experimental data from a laboratory physical model and Al-Daura power station were used for model verification, showing good agreement with observed results

Keywords

ADI method Al-Daura power station Gauss-Elimination method laboratory physical model momentum conservation equation Numerical model river temperature distribution thermal energy equation Thermal pollution Tigris River. turbulence model

5

MIXED CONVECTION FROM ELECTRONIC EQUIPMENT COMPONENT AT DIFFERENT POSITION AN ENCLOUSER BY PRIMITIVE VARABILS METHOD

Jalal M. Jalil, Khalid A. Ismael, Sattar J. Habeeb

Pages: 37-52 English

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Abstract

A numerical study of mixed convtion cooling of heat dissipating electronic component, located in a rectangular enclosure, and cooled by an external through flow of air is carried out.A conjugate problem is solved by primitive variables method, describing the flow and thermal fields in air .The interaction between the components is of interest here, depending on their relative placement in the enclosure, and different configuration are considered. for Re=100 laminar, steady flow is predicted for up to Gr/Re2 =25 according to heat source location in the enclosure. The mixed convection regime, where the buoyancy effects are comparable to the forced flow, occurs at values of Gr/Re2 between 0.01 and 25 .The results are of values in search for suitable placement of electronic components in an enclosed region for an effective heat removal. In general, it appears that the location of the source on the left vertical wall is the most favorable in terms of cooling. Laminar results are predicted up for up to Gr = 2.5*105 for all configurations studied

Keywords

conjugate problem electronic equipment cooling flow and thermal fields Grashof number heat source location Laminar flow mixed convection Numerical simulation Rectangular Enclosure Reynolds Number

6

STUDY OF THE EFFECT OF VEHICLE DRIVER BEHAVIOUR ON VEHICLE EMISSIONS OF CARBON MONOXIDE AT SIGNALIZED INTERSECTIONS

Ali H. Al-Neami, Hamed M. Alani, Aso F.S. Talabany

Pages: 71-84 English

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Abstract

the effect of vehicle driver behaviour on vehicular excess CO emissions at signalized intersections in urban areas. The study was conducted in Erbil City, focusing on four signalized intersections. Traffic data were collected using video recording techniques and the Analytical Mobile Gaseous Emissions CART P8334 machine. The data were analyzed to evaluate the relationship between driver behaviour and CO emissions. The results indicate a significant correlation between queuing driver behaviour and excess CO emissions. The findings are useful for local authorities, traffic engineers, and transportation planners to adopt suitable intersection control methods to reduce CO emissions and air pollution

Keywords

Analytical Mobile Gaseous Emissions CART P8334 Carbon monoxide driver behaviour signalized intersections Statistical analysis traffic data Urban Air Pollution Vehicle emissions video recording

7

PPLICATION OF DECISION SUPPORT SYSTEM IN CONSTRUCTION PROJECTS -10 USE IN COST MANGEMENT

Sidqi I. Razzouqi, Ahmed M. R. Mahjob

Pages: 85-97 English

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Abstract

This research introduces new methods and techniques for project management in the construction industry, focusing on the application of Decision Support Systems (DSS) for cost management. The study highlights the lack of knowledge about DSS among Iraqi engineering staff in the construction sector and presents a proposed DSS for cost control processes. The research includes a questionnaire process for construction companies and uses the results to build the proposed system. The application and evaluation of the system in Iraqi construction companies show the need for DSS in project management

Keywords

construction projects cost control decisions support cost management Decision Support System (DSS) Iraqi construction companies Project Management questionnaire process

8

REMOVAL OF SCALE DEPOSITED ON THE INTERNAL SURFACES OF PIPES IN COOLING SYSTEMS

Abbas H. Sulaymon, Ajwa Saber Majeed

Pages: 99-112 English

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Abstract

This paper investigates the use of inhibited hydrochloric acid for descaling water deposits on heat exchanger and cooling system tubes. A dynamic flow system was designed for this purpose, and experiments were conducted using different temperatures, solution flow rates, times, and concentrations of hydrochloric acid inhibited with hexamine. The kinetics of the acid-iron oxide scale reaction were studied, showing that the reaction follows a first-order process. The results indicate that the iron-oxide scale removal is a mass transfer controlling process, and semi-empirical correlations for scale removal under different conditions were obtained. The Prandtl-Taylor analogy showed good agreement with experimental mass transfer results

Keywords

cale removal Cooling systems dynamic flow system hydrochloric acid inhibited hydrochloric acid iron-oxide scale Mass transfer Prandtl-Taylor analogy

9

APPLICATION OF VIBRATION MEASUREMENT TO DETECT DAMAGE IN CASTING

Adnan N. Jameel Al-Tamimi, Ehab N. Abbas

Pages: 113-126 English

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Abstract

This paper proposes an improved method for damage detection and location in casting using vibration measurement. The study focuses on measuring modal parameters (natural frequency and mode shape) before and after faults of varying extents in three different sizes of Aluminum casing plates. Local damage is characterized as a reduction in local stiffness, which is simulated in numerical models. A statistical method is used to match measured changes in frequencies with theoretical predictions, predicting the most likely defect location. Analytical results are used to verify numerical results, showing good agreement. Standard Aluminum plates were also investigated, and defect location charts were plotted using stiffness sensitivity equations, showing good agreement between predicted and actual defect locations

Keywords

Aluminum casing plates damage detection modal testing mode shape Natural frequency stiffness sensitivity equation structural faults vibration measurement

10

IMPLEMENTATION OF FPGA-BASED RISC FOR LNS ARITHMETIC BY SOFTWARE & HARDWARE

Nabil H. Abbas

Pages: 127-139 English

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Abstract

This paper discusses the implementation of the Logarithmic Number System (LNS) arithmetic using Field Programmable Gate Arrays (FPGAs) and a Reduced Instruction Set Computing (RISC) core. The study highlights the challenges of implementing floating-point operations on FPGAs and proposes LNS as an alternative due to its lower power consumption and faster multiplication and division operations. The paper presents a small RISC core design inspired by the ARM processor, which requires only a 4% additional investment in FPGA resources to significantly improve the speed of LNS addition compared to a pure software approach. The approach leverages shared resources in the data path of the non-LNS parts of the RISC, with the main cost being the decoding and control for the LNS instructions. Preliminary experiments suggest that this method is more cost-effective than pure software and can be as efficient as more expensive LNS-FPGA implementations

Keywords

arithmetic operations ARM processor FPGA hardware implementation Logarithmic Number System (LNS) low power arithmetic RISC Software Implementation Verilog

11

ANODIZING OF ALUMINUM-MAGNESIUM ALLOY USING CHROMIC ACID PROCESS

Adil A. Al-Hemiri, Khalid A. Al-Zameli

Pages: 141-149 English

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Abstract

This paper investigates the anodizing of aluminum-magnesium alloy using chromic acid as an electrolyte. The study examines the effects of voltage (15-60V), electrolyte concentration (20-110 g/l), electrolyte temperature (30-60°C), and time of exposure (25-85 minutes) on the coating weight of the anodic film. Experimental data was fitted to a third-order polynomial, and optimal conditions were predicted: 32V, 85 g/l, 50°C, and 70 minutes. The results provide valuable insights for optimizing the anodizing process of aluminum-magnesium alloys

Keywords

aluminum-magnesium alloy anodizing chromic acid coating weight Electrolyte concentration Optimization temperature third order polynomial Voltage

12

PROBABILISTIC APPROACH TO MACHINE-COMPONENTS GROUPING IN CELLUAR MANUFACTURING SYSTEMS

Zuhair I.A. Al-Daoud

Pages: 151-161 English

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Abstract

his paper reviews existing group technology techniques and introduces an alternative method using a probabilistic approach to machine-components grouping in cellular manufacturing systems. The method is based on production flow analysis, which uses routing information. A common feature of this approach is that it sequentially rearranges rows and columns of the machine part incidence matrix according to predefined indices, generating a block diagonal matrix. The steps involve assigning probability weights to the '1's in each row and column, which are alternately rearranged in descending order until a block diagonal matrix is created. This method does not require deciding the number of required cells in advance and overcomes the limitation of computational complexity inherited in existing group technology methods, especially for large-scale and complex problems

Keywords

Block Diagonal Matrix Cellular Manufacturing Computational complexity Group Technology Machine-Components Grouping Probabilistic Approach Production Flow Analysis

13

AN INVESTIGATION INTO THERMAL PERFORMANCE OF A TAPERED GLASS WINDOW

Luma F. Ali

Pages: 163-179 English

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Abstract

This paper presents a study on the conjugate heat transfer problem through a glass window with non-uniform thickness using the fully implicit finite difference numerical technique. The tapered glass window is subjected to a convective boundary condition on the outer uniform side, while the inside boundary condition is at a constant comfortable temperature. The upper and lower edges of the tapered section are at constant temperatures equal to the mean temperature between the indoor and outdoor temperatures. The study examines different tapered angles and compares the heat loss by convection from the tapered section to a rectangular section. Results indicate that the heat loss increases with time and the tapered angle

Keywords

conjugate heat transfer convective boundary condition finite difference numerical technique heat loss by convection tapered angle tapered glass window

14

EXPERIMENTAL INVESTIGATION OF LAMINAR MIXED CONVECTION IN AN INCLINED ANNULUS

Khalid A. Ismael, Ihsan Y. Hussain, Akeel A. Mohammed

Pages: 181-198 English

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Abstract

This paper presents an experimental study on the local and average heat transfer by mixed convection in a concentric cylindrical annulus with varying inclinations (horizontal, 40°, 70°, and vertical). The experimental setup includes an annulus with a radius ratio of 0.555 and an inner cylinder heated to a constant heat flux, while the outer cylinder is subjected to ambient temperature. The study covers Reynolds numbers ranging from 154 to 845 and heat fluxes from 96 W/m² to 845 W/m². Results show the temperature variation along the inner cylinder surface and the local Nusselt number variation with dimensionless axial distance for all inclination angles. The findings indicate an increase in Nusselt number values as the heat flux increases and as the inclination angle moves from vertical to horizontal

Keywords

Ambient temperature concentric cylindrical annulus constant heat flux Heat flux heat transfer inclined annulus laminar mixed convection Nusselt number Reynolds Number

15

EFFECT OF HARMONICS ON A SOLID-ROTOR INDUCTION MOTOR

Ali M. Saleh, Th. Radhi

Pages: 199-217 English

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Abstract

This paper investigates the performance of a solid-rotor induction motor with rectilinear inverter excitation to identify the effects of associated time harmonics. The performance is determined experimentally using a stator of a three-phase laboratory induction motor fitted with a solid-steel rotor and compared with a theoretical model developed using Fourier components of the supply voltage waveform. The study includes the development of an equivalent circuit model to determine harmonic currents and examines the interactions between co-existing harmonics. The measured values of torque, input current, and power over the full speed range with two types of excitation (sinusoidal and inverter) are presented and compared with theoretical values. The waveforms of current, phase, and line voltages are analyzed experimentally and compared with simulation results. The theoretical results correlate well with measured results, identifying significant harmonic effects

Keywords

equivalent circuit model Fourier components harmonic currents Harmonics input current power rectilinear inverter excitation solid-rotor induction motor stator supply voltage waveform three-phase laboratory induction motor time harmonics torque

16

PRODUCTION OF GRAPHITE ELECTRODES BINDER FROM IRAQI ASPHALT

Abdul Halim A.K. Mohammed, Hussain K. Hussain, Tariq M. Naife

Pages: 219-226 English

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Abstract

This paper investigates the production of graphite electrodes binder using Iraqi asphalt. Basrah crude oil vacuum residue was treated with hexane to prepare deasphaltened oil (DAO) suitable for hydrotreating. The deasphaltening process involved mixing for 1 hour at room temperature with a solvent-to-oil ratio of 10ml:1g. The DAO was then hydrotreated using a presulfided Co-Mo/γ-Al2O3 catalyst in a trickle bed reactor at 660 K, LHSV 1.3 h⁻¹, H2/oil ratio 300 l/l, and constant pressure of 4 MPa. The hydrotreated product was distilled under vacuum, and it was found that a mixture of 75% vacuum residue with 25% anthracene met the requirements for graphite electrodes binder

Keywords

anthracene Basrah crude oil deasphalting Graphite electrodes binder hydrotreating Iraqi asphalt vacuum residue

17

A WAVELET NEURAL NETWORK RAMWORK FOR SPEAKER IDNTIFCATION

W. A. Mahmoud Dhiadeen, M. Salih Saleem, R. Taha

Pages: 227-236 English

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Abstract

This paper introduces a new model-free identification methodology to detect and identify speakers using a novel multi-dimensional wavelet neural network (WNN). The WNN approach leverages the time-frequency localization property of wavelets, leading to reduced networks at a given level of performance. The wavelet transform is applied to non-stationary speech signals to obtain feature vectors, which are then used as inputs to the WNN for classification. The methodology is illustrated with an example, demonstrating its robustness and effectiveness in speaker identification

Keywords

Feature extraction multi-dimensional wavelet neural network non-stationary speech signal Speaker identification time-frequency localization Wavelet neural network

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