M. Zamanian

[ 1 ] - Factor Effect Estimation in the Convective Heat Transfer Coefficient Enhancement of Al2O3/EG Nanofluid in a Double-pipe Heat Exchanger

The forced convective heat transfer (CHT) coefficient of a particular nanofluid, Al2O3 nanoparticles-ethylene glycol (EG) mixture, was investigated experimentally in a double-pipe heat exchanger. The nanofluid Nusselt number for different nanoparticles’ concentrations as well as various operating temperatures was measured to be increased up to 23.7% using 1.0% wt of nanoparticles. The significa...

[ 2 ] - Inhibitive Assesment of Stearamide as a Corrosion Inhibitor for Mild Steel in HCl Solution

In this study effect of Stearamide as a corrosion inhibitor for mild steel in hydrochloric acid media was investigated employing various electrochemical techniques include potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and liner polarization resistance (LPR). In view of the fact that Stearamide is an insoluble compound in water, its inhibitive effect was examined by ...

[ 3 ] - Comparison of Thermal Dispersion Effects for Single and two Phase Analysis of Heat Transfer in Porous Media

The present work involves numerical simulation of a steady, incompressible forcedconvection fluid flow through a matrix of porous media between two parallel plates at constanttemperature. A Darcy model for the momentum equation was employed. The mathematical model forenergy transport was based on single phase equation model which assumes local thermal equilibriumbetween fluid and solid phases. ...

[ 4 ] - Dynamic Analysis of Moving Cables with Variable Tension and Variable Speed

Dynamic Analysis of an axially moving cable with time dependent tension and velocity isstudied in this paper. Tension force and the moving speed are assumed to be harmonic.It is found that there exists a specific value of speed in which natural frequency of the system approacheszero. This specific speed for such a critical condition is called critical speed and it will be proved thatincreasing ...

[ 5 ] - Study of Pitting Corrosion Inhibition of Mild Steel by Nitrite in Concrete Pore Solution by Polarization and Zero Resistance Ammetery (ZRA) Techniques (RESEARCH NOTE)

A research on the corrosion inhibition of mild steel pitting corrosion in concrete pore solution by sodium nitrite was carried out by employing potentiodynamic, potentiostatic polarization and zero resistance ammetery (ZRA) techniques. Passivity breakdown potential was decreased from the transpassive potential of 700 mV at the absence of chloride to a value of -50 mV when just 0.01M NaCl was ad...

[ 6 ] - Synthesise of CoFe2O4-Polyaniline Nanocomposite and Evaluation of its Magnetic Properties

Particles of Cobalt ferrite, CoFe2O4-, were coated with polyaniline (PANI) sulphate and phosphate during in-situ polymerization of aniline in an aqueous solution of sulfuric and phosphoric acid. The PANI-ferrite composites were characterized by Fourier transform infrared (FTIR) spectroscopy. Structures and morphology of products were studied by X-Ray Diffraction (XRD) and Scanning Electron Micr...

[ 7 ] - A New Approach for Buckling and Vibration Analysis of Cracked Column.

In this paper mathematical formulation for buckling analysis of a column and vibrationanalysis of a beam is presented. The beam and the column is assumed to be non-uniform and cracked.Using calculus of variations, the problem is expressed as an optimization problem. A technique ofoptimization is used for analysis of buckling load. Considering the similarity between the governingequation for buc...

[ 8 ] - An Intelligent Vision System on a Mobile Manipulator

This article will introduce a robust vision system which was implemented on a mobile manipulator. This robot has to find objects and deliver them to pre specified locations. In the first stage, a method which is named color adjacency method was employed. However, this method needs a large amount of memory and the process is very slow on computers with small memories. Therefore since the previou...

[ 9 ] - A Numerical Study of Flow and Heat Transfer Between Two Rotating Vertically Eccentric Spheres with Time- Dependent Angular Velocities

The transient motion and the heat transfer of a viscous incompressible flow contained between two vertically eccentric spheres maintained at different temperatures and rotating about a common axis with different angular velocities is numerically considered when the angular velocities are an arbitrary functions of time. The resulting flow pattern, temperature distribution, and heat transfer char...

[ 10 ] - Hydrothermal Synthesis of Aligned Hydroxyapatite Nanorods with Ultra-High Crystallinity

Hydroxyapatite nanorods aligned with ultrahigh crystallinity and high-yield were successfully synthesized through a hydrothermal approach. In this experiment, a new composition of cetyltrimethylammonium bromide ((CH3(CH2)15N+(CH3)3Br-) was designated as CTAP)/Ca(NO3)2/(NH4)2HPO4/NaOH and distilled water under hydrothermal condition, to synthesize single crystalHAp nanorods with diameter of 20 ±...

[ 11 ] - Failure Process of Stone Columns in Collapsible Soils

Many countries in the word have loose and unstable soils encompassing a wide range ofgeological materials, which when inundated, may collapse and cause very significant distress to the structure. Stone columns have been used to strengthen such soils; even so, there are still cases where failure has occurred. In this technical note, the process and causes of stone column failure in reinforcing c...

[ 12 ] - Effects of Pozzolanic Admixture (Waste Bricks) on Mechanical Response of Mortar

This work presents an experimental study realized at the materials laboratory of the University of M’sila. It consists to vary the percentage of the pozzolanic admixture (waste bricks) in cement by the substitution method (partial replacement of the clinker by the calcined clay). The characteristics of cement at anhydrous state and the hydrated state (chemical composition, specific weight and f...

[ 13 ] - Fixing of Cycle Slips in Dual-Frequency GPS Phase Observables using Discrete Wavelet Transforms

The occurrence of cycle slips is a major limiting factor for achievement of sub-decimeter accuracy in positioning with GPS (Global Positioning System). In the past, several authors introduced a method based on different combinations of GPS data together with Kalman filter to solve the problem of the cycle slips. In this paper the same philosophy is used but with discrete wavelet transforms. For...

[ 14 ] - Solution of Wave Equations Near Seawalls by Finite Element Method

A 2D finite element model for the solution of wave equations is developed. The fluid is considered as incompressible and irrotational. This is a difficult mathematical problem to solve numerically as well as analytically because the condition of the dynamic boundary (Bernoulli’s equation) on the free surface is not fixed and varies with time. The finite element technique is applied to solve non...

[ 15 ] - An Improved Modular Modeling for Analysis of Closed-Cycle Absorption Cooling Systems

A detailed modular modeling of an absorbent cooling system is presented in this paper. The model including the key components is described in terms of design parameters, inputs, control variables, and outputs. The model is used to simulate the operating conditions for estimating the behavior of individual components and system performance, and to conduct a sensitivity analysis based on the give...

[ 16 ] - Design, Modeling, Implementation and Experimental Analysis of 6R Robot (TECHNICAL NOTE)

Design, modeling, manufacturing and experimental analysis of a six degree freedom robot, suitable for industrial applications, has been described in this paper. The robot was designed on the assumption that, each joint has an independent DC motor actuator, with gear reduction and measuring sensor for angular joint position. Mechanical design of the robot was done using Mechanical Desktop and ma...

[ 17 ] - Novel Method for the Preparation of Copper Phthalocyanin Blue Nanoparticles in an Electrochemical Cell Irradiated by Microwave (RESEARCH NOTE)

Combined electrochemical and hydrothermal assisted by microwave was used for the preparation of copper phthalocyanin blue (Cu Pc) nanoparticles with sizes ranging from 5 to 35 nm. Phthalic anhydride, urea and ammonium molybdate catalyst were dissolved in aqueous solution of 1 M NH4Cl containing a small amount of lauric acid as capping agent to suppress the flocculation of pigment. Electrodes we...

[ 18 ] - Influences of Track Structure, Geometry and Traffic Parameters on Railway Deterioration

The roles of the several parameters that influences railway track deterioration most, are examined in this research with a view to make railway track maintenance more effective and cost efficient. The results presented are based on a comprehensive study of railway track degradation on super structure, sub-structure and geometrical aspects. The changes in TQI (Track Quality Index), the track set...

[ 19 ] - Investigation on the Effect of Different Parameters in Wheeled Mobile Robot Error (TECHNICAL NOTE)

This article has focused on evaluation and identification of effective parameters in positioning performance with an odometry approach of an omni-directional mobile robot. Although there has been research in this field, but in this paper, a new approach has been proposed for mobile robot in positioning performance. With respect to experimental investigations of different parameters in omni-dire...

[ 20 ] - Behavior of Coupling Beams Strengthened with Carbon Fiber Reinforced Polymer Sheets

In this research, using the results of 6 tests, the effect of Carbon Fiber Reinforced Polymer (CFRP) sheets on the behavior of reinforced concrete coupling beams of shear walls is studied. First, in the experimental part of the study, four coupling beams with different reinforcements were manufactured and tested. Then, after the failure of the specimens, two of them were rehabilitated and stren...

[ 21 ] - A New Hybrid Brushless DC Motor/Generator without Permanent Magnet

The Brushless DC (BLDC) motor is a simple robust machine which has found application over a wide power and speed of ranges in different shapes and geometry. This paper briefly reviews the fundamentals behind the motor and also the different types of BLDC motors with different geometries and then presents a new configuration for BLDC motor/generator, which does not use a permanent magnet in the ...

[ 22 ] - The Effect of Square Splittered and Unsplittered Rods in Flat Plate Heat Transfer Enhancement

A square splittered and unsplittered rod is placed in a turbulent boundary layer developed over a flat plate. The effect of the resulting disturbances on the local heat transfer coefficient is then studied. In both cases the square rod modifies the flow structure inside the boundary layer. As a result, a stagnation point, a jet and wake area are generated around the square rod, each making a co...

[ 23 ] - Nonlinear Analysis of Truss Structures Using Dynamic Relaxation (RESEARCH NOTE)

This paper presents a new approach for large-deflection analysis of truss structures employing the Dynamic Relaxation method (DR). The typical formulation for DR has been established utilizing the finite difference technique which is categorized as an explicit method. The special characteristic of the explicit method is its simple algebraic relationships in comparison with complicated matrix op...

[ 24 ] - Preparation and Study of Molecular Structure of Copper Ions Doped in a Silica Xerogel Matrix

The silica xerogel is prepared using copper source; 0.02 mol of Cu(NO3)2.3H2O that has been added to 1 mol TEOS (tetraethyl orthosilicate). The Copper ions are doped to silica matrix by the sol gel method and determination of total molar ratio of components with a reported molar ratio of H2O /TEOS(R) = 6.2. In this method, the acidity the of reaction (pH) depends on the catalyst type in the hyd...

[ 25 ] - Sealing of Rotary Drums for Operation Under Pressurized Conditions

[ 26 ] - Diffusion Process for GGR Machining System with Spares, Balking and Reneging (RESEARCH NOTE)

This paper deals with the G/G/R machining system consisting of M operating machines as well as S cold standbys. The concepts of balking and reneging are incorporated which make our model more versatile to deal with real time systems. The broken-down machines are sent to repair facilities consisting of R permanent repairmen. The failure times and repair times are generally identical and independ...

[ 27 ] - Trajectory Tracking of a Mobile Robot Using Fuzzy Logic Tuned by Genetic Algorithm (TECHNICAL NOTE)

In recent years, soft computing methods, like fuzzy logic and neural networks have been  presented and developed for the purpose of mobile robot trajectory tracking. In this paper we will present a fuzzy approach to the problem of mobile robot path tracking for the CEDRA rescue robot with a complicated kinematical model. After designing the fuzzy tracking controller, the membership functions an...

[ 28 ] - Unsteady Free Convection from a Sphere in a Porous Medium with Variable Surface Temperature

In this paper a transient free convection flow around a sphere with variable surface temperature and embedded in a porous medium has been considered. The temperature of the sphere is suddenly raised and subsequently maintained at values that varies with position on surface. The method of asymptotic expansions is applied for small Rayleigh numbers and then a finite-difference scheme is used to s...

[ 29 ] - A Parametric Study of the Behavior of Geosynthetic Reinforced Soil Slopes

This paper presents the results of a number of computations using the 2D FEM to show the effects of significant variables on the behavior of geosynthetically reinforced earth slopes. The verification and reliability of the results are primarily examined through comparisons with experimental data available. The results seem to be quite acceptable and can be used with a high degree of reliability...

[ 30 ] - A Reliable and Economically Feasible Automatic Meter Reading System Using Power Line Distribution Network (TECHNICAL NOTE)

Automatic Meter Reading (AMR) is the remote collection of consumption data from customer’s utility meters over telecommunications, radio, power line and other links. AMR provides water, electric and gas utility−service companies the opportunities to streamline metering, billing and collection activities, increase operational efficiency and improve customer service. Utility company uses technolo...

[ 31 ] - Citronellyl Butyrate Synthesis in Non-Conventional Media Using Packed-Bed Immobilized Candida Rugosa Lipase Reactor

The synthesis of citronellyl butyrate by direct esterification reaction catalyzed by immobilized lipase from Candida rugosa was studied in a continuous packed bed reactor using n-hexane as organic solvent. Parameters such as residence time, temperature, and pH were examined. The optimum conversion was obtained at a flow rate of 1 ml/min (residence time 8 min), temperature of 50 °C, and pH 7.5. ...

[ 32 ] - Hydrogen Distribution in Refinery with Nonlinear Programming

[ 33 ] - Development of an Implicit Numerical Model for Calculation of Sub and Super Critical Flows

A two dimensional numerical model of shallow water equations was developed tocalculate sub and super-critical open channel flows. Utilizing an implicit scheme the steady stateequations were discretized based on control volume method. Collocated grid arrangement was appliedwith a SIMPLEC like algorithm for depth-velocity coupling. Power law scheme was used fordiscretization of convection and dif...

[ 34 ] - Pic Microcontroller-Based Automatic Meter Reading (AMR) System Using the Low Voltage (LV) Power Line Network (TECHNICAL NOTE)

Automatic Meter Reading (AMR) is the remote collection of consumption data from customer’s utility meters over telecommunications, radio, power line and other links. AMR provides water, electric and gas utility service companies the opportunity to streamline metering, billing and collection activities, increase operational efficiency and improve customer service. The AMR system consists of thre...

[ 35 ] - Development of an Implicit Numerical Model for Calculation of SUB-and Super-Critical Flows

A two dimensional numerical model of shallow water equations was developed to calculate sub and super-critical open channel flows. Utilizing an implicit scheme the steady state equations were discretized based on a control volume method. Collocated grid arrangement was applied with a SIMPLEC like algorithm for depth-velocity coupling. A power law scheme was used for discretization of convection...

[ 36 ] - Solution of Flow Field Equations and Verification of Cavitation Problem on Spillway of the dam

The main objective of this paper is to formulate a mathematical model for finding flow field and cavitation problem on dam spillways. The Navier-Stokes Equation has been applied for the computation of pressure and velocity field, free water surface profiles and other parameters. Also, for increasing accuracy of the problem, viscosity effect has been considered. Because of internal flows the eff...

[ 37 ] - State Dependent M/M/C/K/N Machining System with Mixed Spares and Removable Repairmen

[ 38 ] - Estimation of Kinetic Parameters of Coking Reaction Rate in Pyrolysis of Naphtha

The run length of cracking furnaces is limited by the formation of coke on the internal skin of the reactor tubes. The reaction mechanism of thermal cracking of hydrocarbons is generally accepted as free-radical chain reactions. On the basis of the plant output data and the insight in the mechanisms for coke formation in pyrolysis reactors, a kinetic model describing the coke formation has been...

[ 39 ] - Performance of Infilled Profiled Steel Sheet Dry Board PSSDB Load Bearing Wall (TECHNICAL NOTE)

This paper describes the testing of Profiled Steel Sheet Dry Board (PSSDB) load bearing wall system. Experimental tests were conducted on various PSSDB wall samples, with and without infill materials to study its effect on the PSSDB load bearing wall performance. A proprietary profiled steel sheet, Ajiya Cliplock (0.48 mm thick) attached to Cemboard (10 mm thick) on one side, and Cemplank (10 m...

[ 40 ] - An Efficient Algorithm to Allocate Parts to Cells Minimizing Total Tardiness and Idle Times

In the design of a cellular manufacturing system (CMS), one of the important problems is the cell formation in the form of machine grouping and parts family. This paper investigates an allocation of parts to common and specific cells; in such a way that each common cell is able to process all required parts. Further, this paper presents a mathematical programming model comprising such constrain...

[ 41 ] - Flow Field Study Over the Wing of a Fighter-Type Aircraft Model

An extensive experimental investigation to study the flow structure over the wing of a fighter type configuration model has been conducted. The model used for this study was similar to the High Alpha Research Vehicle (HARV) that has been used in various European research centers for studying its force and moment characteristics. Tests were conducted at two subsonic speeds and at low to moderate...

[ 42 ] - Numerical Modeling of Mold Filling and Curing in Non-Isothermal RTM Process (RESEARCH NOTE)

Resin Transfer Molding (RTM) is a composite manufacturing process. A preformed fiber is placed in a closed mold and a viscous resin is injected into the mold. In this paper, a model is developed to predict the flow pattern, extent of reaction and temperature change during filling and curing in a thin rectangular mold. A numerical simulation is presented to predict the free surface and its inter...

[ 43 ] - Simulation of Ideal External and Internal Flows with Arbitrary Boundaries Using Schwarz Christoffel Transformation

The flow field, velocity and pressure coefficient distribution of some 2-D ideal flows are presented. Conformal mapping is used to simulate two-dimensional ideal flow for a variety of complex internal and external configurations, based on the numerical integration of Schwarz-Christoffel transformation. The advantages of this method are simplicity and high accuracy. The method presented in this ...

[ 44 ] - Treatment of Wastewater Containing Carbohydrates using Pichia Saitoi Culture

Treatment of wastewater containing carbohydrates by Pichia saitoi growing on beet molasses was investigated in a well-mixed continuous tank as an alternative to bulking control.The yeast strain that used in this work was isolated from non-alcoholic beverage industrial wastewater, with a view on TOC removal compared with other strains in previous study.In this research the isolated yeast showed ...

[ 45 ] - Influence of Compaction Condition on the Microstructure of a Non-Plastic Glacial Till

The influence of compaction water content on the structure has been well known forclayey soils, but has never been studied for granular materials. In this paper the structure of a nonplastictill and the effect of compaction moisture is investigated by means of water retention curvestudy, scanning electron microscopy and mercury intrusion porosimetry tests. The results show thatwhen compacted on...

[ 46 ] - N-Policy for M/G/1 Machine Repair Model with Mixed Standby Components, Degraded Failure and Bernoulli Feedback

In this paper, we study N-policy for a finite population Bernoulli feedback queueing model for machine repair problem with degraded failure. The running times of the machines between breakdowns have an exponential distribution. The repair times of the machines are independent and identically distributed random variables. If at any time a machine fails, it is sent to the repairman for repairing,...

[ 47 ] - Optimal Control of Service Rate in a Service Center with Lapse (Research Note)

The purpose of this paper is to analyze the effect of a particular control doctrine applied to the service mechanism of a queuing process with lapse. It is assumed that the service discipline is FCFS (first come, first served), arrival process is Poisson, service time distribution is exponential, service process is one phase and the capacity is infinite. It is also assumed that the customer may...

[ 48 ] - Continuous Discrete Variable Optimization of Structures Using Approximation Methods

Optimum design of structures is achieved while the design variables are continuous and discrete. To reduce the computational work involved in the optimization process, all the functions that are expensive to evaluate, are approximated. To approximate these functions, a semi quadratic function is employed. Only the diagonal terms of the Hessian matrix are used and these elements are estimated fr...

[ 49 ] - Performance of Biological hydrogen Production Process from Synthesis Gas, Mass Transfer in Batch and Continuous Bioreactors

Biological hydrogen production by anaerobic bacterium, Rhodospirillum rubrum was studied in batch and continuous bioreactors using synthesis gas (CO) as substrate. The systems were operated at ambient temperature and pressure. Correlations available in the literature were used to estimate the gas-liquid mass transfer coefficients (KLa) in batch reactor. Based on experimental results for the con...

[ 50 ] - Modeling of Texture and Color Froth Characteristics for Evaluation of Flotation Performance in Sarcheshmeh Copper Pilot Plant, Using Image Analysis and Neural Networks

Texture and color appearance of froth is a discreet qualitative tool for evaluating the performance of flotation process. The structure of a froth developed on the flotation cell has a significant effect on the grade and recovery of copper concentrate. In this work, image analysis and neural networks have been implemented to model and control the performance of such a system. The result reveals...

[ 51 ] - Effect of Solid-State on Load Distribution Transformer Tap-Changer on Power Quality Enhancement

Recently electronic tap-changer has received more attention due to its quick response, better performance and simpler maintenance compared to the mechanical tap-changer. This paper presents the capability of the distribution transformer equipped with an electronic tap-changer for improving power quality. At this end, the analytical computation for determining the compensating limit of electroni...

[ 52 ] - Reliability Analysis of Redundant Repairable System with Degraded Failure

This investigation deals with the transient analysis of the machine repair system consisting of M-operating units operating under the care of single repairman. To improve the system reliability/availability, Y warm standby and S cold standby units are provided to replace the failed units. In case when all spares are being used, the failure of units occurs in degraded fashion. In such situation ...

[ 53 ] - Creep Life Assessment of Primary Reformer HP40-NB Modified Steel Tube of an Ammonia Plant

Assessment of creep damage and residual creep life of a cast HP 40 Nb Mod. Reformer tube was performed, wherein the experimental Larson–Miller diagram and area fraction of creep voids were adopted. The state of damage of the tube in service was metallographically analyzed by using light and electron microscopy. Samples from the serviced reformer furnace tube were cut and prepared for void exami...

[ 54 ] - Gum Tragacanth Fibers Introducing Primitive GT Fibers (RESEARCH NOTE)

In this research, a method for producing gum tragacanth (GT) fibers is presented. Ribbon type GT of Astragalus Gummifer species were obtained from local production lands. The gum was treated with alkali to increase its process ability, and allowed to stand for a period of time to reach the proper viscosity and/or to "ripen". Samples with different ripening times were prepared and their viscosit...

[ 55 ] - Pressure-Velocity Coupled Finite Volume Solution of Steady Incompressible Invscid Flow Using Artificial Compressibility Technique

Application of the computer simulation for solving the incompressible flow problems motivates developing efficient and accurate numerical models. The set of Inviscid Incompressible Euler equations can be applied for wide range of engineering applications. For the steady state problems, the equation of continuity can be simultaneously solved with the equations of motion in a coupled manner using...

[ 56 ] - Solving a Stochastic Cellular Manufacturing Model by Using Genetic Algorithms

This paper presents a mathematical model for designing cellular manufacturing systems (CMSs) solved by genetic algorithms. This model assumes a dynamic production, a stochastic demand, routing flexibility, and machine flexibility. CMS is an application of group technology (GT) for clustering parts and machines by means of their operational and / or apparent form similarity in different aspects ...

[ 57 ] - Performance Modeling of Machining System with Mixed Standby Components Balking and Reneging

This paper deals with machine repair problem with balking and reneging. There is provision of mixed standby (warm and cold) components to replace the failed machines. The lifetime and repair time are assumed to have exponential distribution. Birth-death technique is suggested to obtain the queue size distribution in explicit form. A repair facility of C permanent repairmen is facilitated to rep...

[ 58 ] - Behavior of Packed Bed Thermal Storage

A packed bed thermal storage has several desirable characteristics to be used for energy storage. The behavior of packed bed is predicted by set of differential equations. A numerical solution is developed for packed bed storage tank accounting to the secondary phenomena of thermal losses and conduction effect. The effect of heat loss to surrounding (K1), conduction effect (K2) and air capacita...

[ 59 ] - Optimal Load of Flexible Joint Mobile Robots Stability Approach

Optimal load of mobile robots, while carrying a load with predefined motion precision is an important consideration regarding their applications. In this paper a general formulation for finding maximum load carrying capacity of flexible joint mobile manipulators is presented. Meanwhile, overturning stability of the system and precision of the motion on the given end-effector trajectory are take...

[ 60 ] - The Effect of Asymmetric Water Entry on the Hydrodynamic Impact

The effect of the asymmetric water entry over a submerged part of a ship on the hydrodynamic impact is investigated numerically. A wedge body is considered to study and the problem is assumed to be two-dimensional. The Results of symmetric and asymmetric impacts are compared together. The effect is found significant in the numerical simulation. The maximum hydrodynamic pressure at a heel angle ...

[ 61 ] - Optimizing of Steel Fiber Reinforced Concrete Mix Design

Cementitious matrices are the fragile materials that possess a low tensile strength. The addition of fibers randomly distributed in these matrices improves their resistance to cracking, substantially. However, the incorporation of fibers into a plain concrete disrupts the granular skeleton and quickly causes problems of mixing as a result of the loss of mixture workability that will be translat...

[ 62 ] - Experiments To Determine The Simulated Annealing Parameters Case Study In VRP

In this paper we describe the distribution problems faced by one of the largest retailers in the distribution and sale of fast moving consumer goods in the U.K. The paper describes an initial solution method, which is then improved by a novel form of simulated annealing. A computational experiment for the improvement algorithm has been also carried out in order to illustrate the flexibility of ...

[ 63 ] - Effect of Composition and MnS Addition on Microstructure and Mechanical Properties of Powder Forged Copper Steel Parts

In this work, the effects of carbon content and manganese sulfide addition on the microstructure and mechanical properties of copper steel parts have been studied. Steel powder mixture containing 2%Cu and different graphite contents with and without MnS additions were compacted, sintered and forged to almost full density. Forged samples, with near theoretical densities, were tested for tensile,...

[ 64 ] - New Stilling Basins Designs for Deep Rectangular Outlets

The experimental study reported here is intended to evolve new designs of stilling basins for deep and narrow openings used as outlets. Several appurtenances such as grid, Impact wall, stepped wall, weir wall, sloping end sill and wedge shaped blocks are used to study their influence on the hydraulic performance of the stilling basins with an aim to propose efficient stilling basin models. All ...

[ 65 ] - Automatic Phase Advancing in Switched Reluctance Motor by Employing an Electronic Governor for a Desired Speed Angle Profile

Switched reluctance motor (SRM) drive has remarkable characteristics that make it attractive for high-speed applications. As the motor's speed increases the shape of the current waveform changes in such way that limits the production of motoring torque. At high speeds, it is possible for the phase current never reaches the desired value due to the self e.m.f. of the motor, therefore, the torque...

[ 66 ] - A Very Low Voltage 9th Order Linear Phase Baseband Switched Capacitor Filter (RESEARCH NOTE)

A very low voltage 9th order linear phase baseband switched capacitor (SC) filter has been designed to be used as part of a cellular GSM (Global System Mobile) receiver. A Gaussian-to-6dB filter of the order of seven is chosen and a second order function is added to reduce the group delay variations around. The filter uses a fully differential topology to increase the dynamic range and reduce t...

[ 67 ] - On the Approximation of Pseudo Linear Systems by Linear Time Varying Systems (RESEARCH NOTE)

This paper presents a modified method for approximating nonlinear systems by a sequence of linear time varying systems. The convergence proof is outlined and the potential of this methodology is discussed. Simulation results are used to show the effectiveness of the proposed method.

[ 68 ] - Integrated Approach for Cellular Manufacturing a Case Study (TECHNICAL NOTE)

To cope with fast changing customer requirements, industrial demands and to meet stringent specifications of customers Cellular Manufacturing Systems has become an effective tool in hands of manufacturers. Most of the published literature on cell formation earlier considers only the data available in the route sheets and ignored subproblems associated with cell formation. There is a need to dev...

[ 69 ] - A Numerical Study on Mixing of Transverse Injection in Supersonic Combustor

A numerical study on mixing of hydrogen injected transversely into a supersonic air stream has been performed by solving Two-Dimensional full Navier-Stokes equations. An explicit Harten-Yee Non-MUSCL Modified-flux-type TVD scheme has been used to solve the system of equations, and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. The main objectives of this...

[ 70 ] - Capacitive Flux Compression Generator (RESEARCH NOTE)

Conventional Flux Compression Generators (FCG's) are used to generate high power DC pulses. A new kind of (FCG's) with series capacitance called Capacitive Flux Compression Generator (CFCG) will be introduced and explained in this paper. This new kind is used to generate modulated high power pulses. There are some problems to establish a capacitance in high power and high frequency applications...

[ 71 ] - A Study of Zeta Potential of Plasma Sprayed Hydroxyapatite Coating in Four Simulated Physiological Solutions

The zeta potential magnitude and the duration of its changes have been thought to be directly related to the surface reactivity, the governing of osteoconductivity and availability of valuable information in determining the anticipated in-vivo performance of implants. In this study the zeta potential of plasma sprayed hydroxyapatite (HA) was evaluated in various simulated physiological solution...

[ 72 ] - An Instantaneous Rigid Force Model For 3-Axis Ball-End Milling Of Sculptured Surfaces

An instantaneous rigid force model for prediction of cutting forces in ball-end milling of  sculptured surfaces is presented in this paper. A commercially available geometric engine is used to represent the cutting edge, cutter and updated part geometries. The cutter used in this work is an insert type ball-end mill. Intersecting an inclined plane with the cutter ball nose generates the cutting...

[ 73 ] - Integrator Backstepping Control of a 5 DoF Robot Manipulator with Cascaded Dynamics

In this paper, dynamic equations of motion of a 5 DoF robot manipulator including mechanical arms with revolute joints and their electrical actuators are considered. The application of integrator backstepping technique for trajectory tracking in presence of parameters of uncertainty and disturbance is studied. The advantage of this control technique is that it imposes the desired properties of ...

[ 74 ] - Study on the Interactions between Mechanical and Structural Properties of the Thermobonded Nonwovens

Thermobonding is widely used in producing of nonwovens. In this study various layers of thermobonded nonwovens were produced by altering the pressure, binder fibres and quality of blending. Mechanical properties of the so-called layers such as breaking strength and breaking elongation, bending rigidity and air permeability were assessed consequently. The structure of the layers was then studied...

[ 75 ] - Significant Error Propagation in the Finite Difference Solution of Non-Linear Magnetostatic Problems Utilizing Boundary Condition of the Third Kind

This paper poses two magnetostatic problems in cylindrical coordinates with different permeabilities for each region. In the first problem the boundary condition of the second kind is used while in the second one, the boundary condition of the third kind is utilized. These problems are solved using the finite element and finite difference methods. In second problem, the results of the finite di...

[ 76 ] - Blind Separation of Jointly Stationary Correlated Sources

The separation of unobserved sources from mixed observed data is a fundamental signal processing problem. Most of the proposed techniques for solving this problem rely on independence or at least uncorrelation assumption for source signals. This paper introduces a technique for cases that source signals are correlated with each other. The method uses Wold decomposition principle for extracting ...

[ 77 ] - Permanent Magnet DC Motor Sliding Mode Control System

In this paper a sliding mode controller (SMC) is designed for a permanent magnet direct current (PMDC) motor to enhance the motor performance in the presence of unwanted uncertainties. Both the electrical and mechanical signals are used as the inputs to the SMC. The complete motor control system is simulated on a personal computer with different design parameters and desirable system performanc...

[ 78 ] - M1, M2, ..., Mk/G1, G2,..., Gk/l/N Queue with Buffer Division and Push-Out Schemes for ATM Networks (RESEARCH NOTE)

In this paper, loss probabilities and steady state probabilities of data packets for an asynchronous transfer mode (ATM) network are investigated under the buffer division and push-out schemes. Data packets are classified in classes k which arrive in Poisson fashion to the service facility and are served with general service rate under buffer division scheme, finite buffer space N is divided in...

[ 79 ] - Modeling the Tensile Behavior of Fibers with Geometrical and Structural Irregularities

Virtually all fibers exhibit some dimensional and structural irregularities. These include the conventional textile fibers, the high-performance brittle fibers and even the newly developed nano-fibers. In recent years, we have systematically examined the effect of fiber dimensional irregularities on the mechanical behavior of the irregular fibers. This paper extends our research to include the ...

[ 80 ] - Applicability of Elastic Analysis for Predicting the Settlement Distribution Around Tunneling in Soft Ground (TECHNICAL NOTE)

In this article a brief review of the literature on the subject is cited. The method of analysis by a finite element program is discussed in which the effect of different influential parameters are examined. The results of these computations are then compared to the corresponding empirical data and two other existing formulae for two dimensional cases. The comparisons show quite reliable and ac...

[ 81 ] - Application of SVC on Large Synchronous Motors Based on LOC Design (RESEARCH NOTE)

This paper describes the application of static var compensators, (SVC) on an electrical distribution network containing two large synchronous motors, one of which is excited via a three-phase thyristor bridge rectifier. The second machine is excited via a diode bridge rectifier. Based on linear optimization control (LOC), the measurable feedback signals are applied to the control system loops o...

[ 82 ] - Synergistic Influence of Benzoate Ions on Inhibition of Corrosion of Mild Steel in 0.5m Sulfuric Acid by Benzotriazole

The influence of benzoate anions on the corrosion inhibition effect of benzotriazole (BTA) for mild steel in sulfuric acid has been investigated. The investigation was carried out by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The addition of benzoate ions greatly enhances the inhibition efficiency of BTA in a synergistic manner. This effect has bee...

[ 83 ] - Influence of an Inclusion on Multi-Pass Copper Shaped-Wire Drawing by 2D Finite Element Analysis

The size and length effects of an inclusion on multi-pass copper shaped-wire drawing were investigated. For this purpose, an experimental investigation on optimal die half-angle was conducted. Based on experimental data of optimal die half-angle, wire and inclusion deformations, drawing and hydrostatic stress of copper shaped-wires that contain an inclusion were calculated by two-dimensional fi...

[ 84 ] - Role of Calcium Content in Dissolution Kinetics of Iranian Borate Minerals in Sulfuric Acid

The dissolution kinetics of pandermite and hydroboracite, present in an Iranian borate ore, in sulfuric acid has been comparatively studied. The effect of particle size, temperature, and acid concentration on their dissolution rate was investigated. Dissolution rates of both minerals increased by reducing the particle size and by raising the temperature. Although, an increase in the acid concen...

[ 85 ] - Full Analysis of Low Finned Tube Heat Exchangers

In this paper, first the governing parameters characterizing low-finned tubes are reviewed. Second, the more important of the available performance correlations are compared with the available experimental data. The most reliable one can be employed to develop a pressure drop relationship, which has already been used in an algorithm for exchanger sizing. Also a means for the identification of a...

[ 86 ] - A Novel Fuzzy and Artificial Neural Network Representation of Overcurrent Relay Characteristics

Accurate models of Overcurrent (OC) with inverse time relay characteristics play an important role for coordination of power system protection schemes. This paper proposes a new method for modeling OC relays curves. The model is based on fuzzy logic and artificial neural networks. The feed forward multilayer perceptron neural network is used to calculate operating times of OC relays for various...

[ 87 ] - Calculation of Complicated Flows, Using First and Second-Order Schemes (RESEARCH NOTE)

The first-order schemes used for discretisation of the convective terms are straightforward and easy to use, with the drawback of introducing numerical diffusion. Application of the secondorder schemes, such as QUICK scheme, is a treatment to reduce the numerical diffusion, but increasing convergence oscillation is unavoidable. The technique used in this study is a compromise between the above-...

[ 88 ] - Maximum Allowable Load On Wheeled Mobile Manipulators (RESEARCH NOTE)

This paper develops a computational technique for finding the maximum allowable load of mobile manipulators for a given trajectory. The maximum allowable loads which can be achieved by a mobile manipulator during a given trajectory are limited by the number of factors; probably the dynamic properties of mobile base and mounted manipulator, their actuator limitations and additional constraints a...

[ 89 ] - Modeling of the Combustion Oscillations and Soot Formation in Aerovalved Pulse Combustors

This paper describes the modifications and evolution of a thermal pulse combustionmodel for predicting the combustion oscillations of an aerovalved 250 kW pulse combustorincorporating a soot formation-combustion model. Validation of the model is carried out from theexperimental data of an aerovalved Helmholtz type pulse combustor, where a sinusoidal air inlet massflow coupled with pressure osci...

[ 90 ] - A New Approach for Determination of Break Points for Protection Co-Ordination

Interconnected power system networks are multi loop structured. Settings determination of all over current and distance relays in such networks can be in different forms and complicated. The main problem is the determination of starting points i.e. the location of starting relays in the procedure for settings, which is referred to as break points. In this paper, a new approach based on graph th...

[ 91 ] - Treatability Evaluation of Municipal Wastewater and Anaerobically-Treated Industrial Effluent in a Rotating Biological Contactor

Performance of a rotating biological contactor (RBC) in treating municipal wastewater from primary sedimentation basin and anaerobically treated industrial effluent from an upflow anaerobic sludge blanket (UASB) reactor was investigated. The 280-L six-stage RBC pilot was operated at different organic loading rates and biodisc speeds. The overall removal efficiencies of soluble BOD decreased wit...

[ 92 ] - Evaluation of Forming Severity and Thickness Variation in Deep Drawing Process

This paper presents a new methodology for complete solution of general shape deep drawn parts. Evaluation of forming severity, estimation of the punch load and prediction of the thickness variation are the major results obtained in this work. The punch work is the summation of the homogenous work of flange deformation and bending and frictional works. To evaluate the strain energy of the flange...

[ 93 ] - An Experimental and Theoretical Study of Freezing of Pure Aluminum

In this work, Boltzmann transform has been used to analyze the problem of freezing of pure Aluminum in semi-infinite domain. The uniqueness of solution (solidification front location) has been proved using the characteristics of the functions appeared in solution. The effect of density change on temperature distribution and errors resulting from ignoring this change have been investigated. The ...

[ 94 ] - The Development and Validation of New Equations for Prediction of the Performance of Tangential Cyclones

New equations have been developed to predict the effect of geometrical dimensions of tangential cyclones on their operational performances. To check the validity of the derived equations, an experimental apparatus was set up and some experimental work was performed. It was observed that the experimental results confirm properly the theoretical predictions.

[ 95 ] - A Scale-up Design Procedure for Rotating Biological Contactors

A scale-up design procedure, based on a new physical mass transfer (PMT) model, whichdescribes the performance, for aerobic rotating biological contactors (RBC’s) is developed. This scale-up procedure can be used to determine the disc surface area needed to prevent an oxygen limitation or to obtain a specific degree of treatment. In contrast to the empirical, and most previous RBC performance m...

[ 96 ] - Slope Stability Analysis Using A Non-linear Optimization Technique (RESEARCH NOTE)

In this study, a limit equilibrium method has been developed that satisfies all conditions of equilibrium and assumes circular slip surfaces. All force and moment equilibrium equations are employed without using simplification assumptions. A non-linear optimization technique is used to solve the system of equations with the corresponding constraints. The proposed method is capable to determine ...

[ 97 ] - Maximum Entropy Analysis for G/G/1 Queuing System (TECHNICAL NOTE)

This paper provides steady state queue-size distribution for a G/G/1 queue by using principle of maximum entropy. For this purpose we have used average queue length and normalizing condition as constraints to derive queue-size distribution. Our results give good approximation as demonstrated by taking a numerical illustration. In particular case when square coefficient of variation of inter-arr...

[ 98 ] - Numerical Simulation of the Wake Flow Behind an Ellipse using Random Vortex Method (RESEARCH NOTE)

Direct numerical simulation of the wake flow around and behind a planar ellipse using a random vortex method is presented. Fluid is considered incompressible and the aspect ratios of ellipse and the angles of attacks are varied. This geometry can be a logical prelude to the more complex geometries, but less time dependent experimental measurements are available to validate the numerical results...

[ 99 ] - Computational Study of Radiative and Convective Heat Transfer in a Cylindrical Combustion Chamber

In this paper, the effect of cold air on the fluid flow inside the cylindrical combustion chamber and its wall temperature distribution have been studied computationally, taking into account the effect of radiative heat transfer from hot gases. The results have been compared with the case that radiative heat transfer was neglected. It is observed that the reattachment length increases when incr...

[ 100 ] - The Effect of Sulfate Concentration on COD Removal and Sludge Granulation in UASB Reactors

Four identical 37.5 Liter UASB reactors R1, R2, R3 and R4 were used to study the effect of sulfate concentration on granule formation. Diluted molasses with COD range 1000–1300 mg/l were used as feed and acclimated cow manure was used as seed. Concentration of sulfate ions in the four reactors were 100, 500, 1000 and 1500mg/l. Granules were observed in R2 after 33 days from startup time, while ...

[ 101 ] - Coupled Anaerobic Baffled Reactor (ABR)/Activated Sludge Treatment of Synthetic Wastewater with High Concentration of Sulfate and COD

A synthetic wastewater with high concentration of sulfate and COD was treated in anaerobic baffled reactor (ABR) coupled with an activated sludge. The work was accomplished in two phases. In the first phase, the concentration of sulfate was kept constant at 500mg/l, but COD concentration was increased from (3000mg/l to 6000mg/l), consequently, COD and sulfate removal in ABR reached to 80% and 9...

[ 102 ] - Hot Corrosion Behavior of Magnesite – Chromite Refractories Used in Reverberatory Furnaces at Sarcheshmeh Copper Complex

Iran’s Sarcheshmeh copper industries with an annual production of 120,000 tones are the biggest of it’s kind in South Asia. The main method of production is pyrometallurgical matte making in two reverberatory furnaces which use direct–bond magnesite-chromite refractories supplied by German and Austrian companies. Following a recent major overhaul, bricks in contact with slag, matte and furnace ...

[ 103 ] - Comparative Cyanide and Thiourea Extraction of Gold Based on Characterization Studies (TECHNICAL NOTE)

This study involved preliminary laboratory test work to identify the relative leaching response to cyanidation and thiourea leaching of an oxidized low grade gold ore based on characterization studies. Huge reserves of gold deposits have been reported from different parts of Iran, especially at Neishaboor area with gold grade of approx 4 ppm. For the mineralogical composition, the nature of the...

[ 104 ] - Numerical Solution of Reacting Laminar Flow Heat and Mass Transfer in Ducts of Arbitrary Cross-Sections for Newtonian and Non-Newtonian Fluids

This study is concerned with the numerical analysis, formulation, programming and computation of steady, 3D conservation equations of reacting laminar flow heat and mass transfer in ducts of arbitrary cross-sections. The non-orthogonal boundary-fitted coordinate transformation method is applied to the Cartesian form of overall-continuity, momenta, energy and species-continuity equations, parabo...

[ 105 ] - Determination of Suitable Concentrations of H2O and CO2 in the Feed of Syngas Production (RESEARCH NOTE)

Modeling and optimization of synthesis gas production via the non-catalytic partial oxidation of methane (NCPO) were studied by minimizing of Gibbs free energy, and comparison studies were carried out to analyze the mechanism of syngas production. For this purpose, concentrations of CO2 and H2O in the feed were optimized in specified pressure and temperature, such that the hydrogen to carbon mo...

[ 106 ] - Software for Kinetic Process Simulation (RESEARCH NOTE)

The relationship between velocity of chemical reactions with activities or concentrations of their reactants, temperature and pressure and the mechanisms through which the reactions proceed are of interest to many scientists and engineers. The purpose of this article is to introduce a computer software that is developed for calculation, classification and collection of such data. The applicatio...

[ 107 ] - Efficiency of Anti-Hourglassing Approaches in Finite Element Method (TECHNICAL NOTE)

one of the simplest numerical integration method which provides a large saving in computational efforts, is the well known one-point Gauss quadrature which is widely used for 4 nodes quadrilateral elements. On the other hand, the biggest disadvantage to one-point integration is the need to control the zero energy modes, called hourglassing modes, which arise. The efficiency of four different an...

[ 108 ] - Mechanical Properties of Irregular Fiber (Invited Review Paper)

Irregularities are inherent to virtually all fibers, including the conventional textile fibers, the high-performance brittle fibers and newly developed nano-fibers. These irregularities can fall into two main categories: dimensional or geometrical irregularity (external) and structural irregularity (internal). For natural fibers such as wool, diameter variation along fiber length is atypical ex...

[ 109 ] - Seismic Response of the Kavar Concrete Face Rockfill Dam (RESEARCH NOTE)

This study deals with the dynamic behavior of the kavar concrete Abstract face rockfill damwhich is the first dam of this type to be const ructed in a highly active seismic prone area,situated in the state of Fars southern part of the Islamic Republic of Iran. The finite elementmethod was used as a tool to carry out this study. The finite element discretization was carriedout under plane strain...

[ 110 ] - The Opportunities Afforded by Embedded Computer Systems for Monitoring and Control of Industrial Processes in Less-Industrialised Countries (TECHNICAL NOTE)

The dramatic changes in integrated-circuit technology over the last two decades have been of great benefit to countries such as Zimbabwe. High volume production of VLSI chips has produced a supply of intelligent, versatile electronic processing devices at very low cost. In particular the facilities of the microcontroller have steadily developed to the accompaniment of a reduction in price. Sinc...

[ 111 ] - The Overall Heat Transfer Characteristics of a Double Pipe Heat Exchanger: Comparison of Experimental Data with Predictions of Standard Correlations

The single-phase flow and thermal performance of a double pipe heat exchanger are examined by experimental methods. The working fluid is water at atmospheric pressure. Temperature measurements at the inlet and outlet of the two streams and also at an intermediate point half way between the inlet and outlet is made, using copper-constantan thermocouple wires. Mass flow rates for each stream are ...

[ 112 ] - Development of an Intelligent Cavity Layout Design System for Injection Molding Dies (RESEARCH NOTE)

This paper presents the development of an Intelligent Cavity Layout Design System (ICLDS) for multiple cavity injection moulds. The system is intended to assist mould designers in cavity layout design at concept design stage. The complexities and principles of cavity layout design as well as various dependencies in injection mould design are introduced. The knowledge in cavity layout design is ...

[ 113 ] - Performance Prediction of a Flexible Manufacturing System

The present investigation presents a stochastic model for a flexible manufacturing system consisting of flexible machine, loading/unloading robot and an automated pallethandling device. We consider unreliable flexible manufacturing cell (FMC) wherein machine and robot operate under individual as well as common cause random failures. The pallethandling system is completely reliable. The pallet o...

[ 114 ] - Numerical Study of Blast Initiation of Detonation Using a Two Step Chemical Kinetics Model

The effect of chemical reactions on the blast initiation of detonation in gaseous media has been investigated in this paper. Analytical method is based on the numerical solution of onedimensional reactive Euler equations. So far, analyses on the blast initiation of detonation have modeled the combustion process as a one-step chemical reaction, which follows the Arrhenius rate law. Previous stud...

[ 115 ] - Microbial Desulfurization of Malaysian Coal in Batch Process using Mixed Culture (RESEARCH NOTE)

Biodesulfurization of coal has been carried out in batch culture of single strain and mixed culture of sulfur oxidizing bacteria. The pure cultures of Thiobacillus thiooxidans and Thiobacillus ferrooxidans utilized inorganic sulfur content of Malaysian coal. The chemolithotroph bacteria were able to grow on coal and metabolize the coal's sulfur content. The batch cultures of coal with 3-5 perce...

[ 116 ] - Kinetics of Benzyl Chloride Production in a Bench Reactor Under Pressure with Stirrer (TECHNICAL NOTE)

Benzyl chloride is economically one of the most important starting materials for a large number of industrial syntheses. Far too much money is now spent to buy and import this valuable product. The production of benzyl chloride has been recognized as one of our national projects and budgeted by the National Iranian Petrochemical Organization in order to economize on the country’s foreign exchan...

[ 117 ] - Morphological Characterization of Combustion Deposited Diamond Crystals and Films

Single crystals and polycrystalline diamond films of several thicknesses were deposited using oxygen/acetylene combustion flame technique. The substrate used was pure polycrystalline molybdenum subjected to mechanical polishing. Quality and microstructural characteristic of diamond produced were investigated using X-Ray diffraction, Raman Spectroscopy, Scanning and Transmission Electron Microsc...

[ 118 ] - Effect of Impact Parameters on Explosive Welding of Tube to a Plug

Effects of some important parameters like impactor effects, plug geometry and initiation points on bonding aluminum tubes to aluminum plugs were studied. The impact velocity and dynamic angle between tube and plug should be precisely managed to achieve an optimum bonding condition. A new explosive bonding technique with the use of two material impactors was proposed. Results are especially suit...

[ 119 ] - The Development of a Passive False Twister Mechanism in Handling Low Strength Cotton Slivers on High Draft Spinning Machine

A passive false twist unit (spiral) has been developed to assist with the handling lowstrength slivers on a high speed-spinning machine with a high-speed feed. In the first trial, a falsetwist simulator device was constructed to determine whether the passive false twist unit can be usedon high speed feeding with different can distance from the feeding device. In the second trial, theeffects of ...

[ 120 ] - Thermal Development for Ducts of Arbitrary Cross Sections by Boundary-Fitted Coordinate Transformation Method

The non-orthogonal boundary-fitted coordinate transformation method is applied to the solution of steady three-dimensional momentum and energy equations in laminar flow to obtain temperature field and Nusselt numbers in the thermal entry region of straight ducts of different cross sectional geometries. The conservation equations originally written in Cartesian coordinates are parabolized in the...

[ 121 ] - State Dependent Multi channel Queuing System with Ordered Entry

In the present study, we analyze the multi-channel service system with ordered entryfrom finite-source and finite-storage at each channel. The arrival and service rates are assumedto be state dependent. The steady state probabilities of the system are obtained by usingChapmann-Kolmogorov equations. Some other performance indices viz. utilization of servers,expected number of units in the system...

[ 122 ] - Finite Volume Solution of a Cylinder in Cross Flow with Heat Transfer

A finite-volume model has been developed to study incompressible forced flow heat transfer of air over a circular cylinder in cross flow. An artificial compressibility technique is applied to couple the continuity to the momentum equations. The proposed explicit finite-volume method (FVM) uses a novel discretization in time and space. The governing equations are solved by time-marching using a ...

[ 123 ] - A New Approach to Self-Localization for Mobile Robots Using Sensor Data Fusion

This paper proposes a new approach for calibration of dead reckoning process. Using the well-known UMBmark (University of Michigan Benchmark) is not sufficient for a desirable calibration of dead reckoning. Besides, existing calibration methods usually require explicit measurement of actual motion of the robot. Some recent methods use the smart encoder trailer or long range finder sensors such ...

[ 124 ] - Determination of Load and Strain-Stress Distributions in Hot Closed Die Forging Using the Plasticine Modeling Technique

An axisymmetric hot closed die-forging process has been studied by physical modeling technique using the plasticine. To observe the material flow pattern, layers of plasticine with different colors were used. The normal direction to the layers was considered a principal direction. The strain distribution was obtained by measuring the thickness of the plasticine layers. Based on the strain distr...

[ 125 ] - Interface Characterization of Plasma Sprayed Hydroxyapatite Coat on Ti 6Al 4V

Hydroxyapatite (HA), a material proven to be biocompatible within the human body, has been produced to a high level of purity. This material has been applied as a coating on Ti-6Al-4V alloy by using the air plasma spraying technique. The coat was characterizted with SEM, XRD, FTIR and Raman spectroscopy methods to consist of a mixture of calcium phosphates including HA mainly and traces of tric...

[ 126 ] - Effect of Particle Size Distribution and Chemical Composition on Properties of Magnesia Chromite Bricks

The present study was undertaken to improve the quality and increase the life time of magnesia-chromite refractory bricks used in the copper and lead industries. The results show that a decrease in the amount of large chromite particles in the formulation improves the thermomechanical properties and also reduces the slag penetration in the bricks. In addition it was also observed that the use o...

[ 127 ] - Bit Error Performance for Asynchronous Ds Cdma Systems Over Multipath Rayleigh Fading Channels (RESEARCH NOTE)

In recent years, there has been considerable interest in the use of CDMA in mobile communications. Bit error rate is one of the most important parameters in the evaluation of CDMA systems. In this paper, we develop a technique to find an accurate approximation to the probability of bit error for asynchronous direct–sequence code division multiple–access (DS/CDMA) systems by modeling the multipl...

[ 128 ] - Performance Improvement of Expanded Integrated Local Area Networks (RESEARCH NOTE)

In Local Area Networks (LAN) connected together by bridges, flow control and smooth traffic in the network is very important. However, congestion at bridges can cause intensive loss of received frames. In addition, the received frames are thrown away and have to be retransmitted by the source station, which causes more congestion and massive reduction in the overall network throughput. The netw...

[ 129 ] - Optimization of M G 1 Queue with Vacation (TECHNICAL NOTE)

This paper reports on the minimization of the average waiting time of the customers in the M/G/1 queue with vacation. Explicit formula for the unknown service parameter of a particular customer has been obtained by considering the exhaustive service discipline in the case of multi-user with unlimited service system. Moreover, results in case of partially gated and gated service disciplines unde...

[ 130 ] - A Boundary Elements and Particular Integrals Implementation for Thermoelastic Stress Analysis

A formulation and an implementation of two-dimensional Boundary Element Method (BEM) analysis for steady state, uncoupled thermoelastic problems is presented. This approach differs from other treatments of thermal loads in BEM analysis in which the domain integrals due to the thermal gradients are to be incorporated in the analysis via particular-integrals. Thus unlike Finite Elements or Field ...

[ 131 ] - An Experimental Investigation of Bridgeflow II Kerb Channel Units

The results of an experimental investigation of kerbside bridge deck drainage units are presented. The conveyance capacity, resistance coefficients and sediment transporting efficiencies of different types of drainage unit used in shallow bridge drainage decks are examined over a range of bed gradients likely to be encountered in practice. The use of a V-shaped cross section is shown to be part...

[ 132 ] - Allocation of Posts to a Tele-Communication Center Through Kavos (RESEARCH NOTE)

Every phone company customer in a given region receives phone services from a switching center through intermediate points called kavos. The problem addressed in this paper is where to locate this central facility and the kavos, how many of them and with what capacity, so that the total cable length is minimized. This problem can be formulated as a 0-1 mixed integer program; However, because of...

[ 133 ] - Influence of Residual Stress on Fatigue Life of Hot Forged and Shot Blasted Steel Components

Hot forging is a common manufacturing process for the production of large quantities of engineering components. Residual stresses are developed in forged components as a result of various aspects of the manufacturing process, including subsequent cooling, and heat treatment. Residual stresses can significantly affect the deformation and fatigue failure of materials. Hot forged EN15R steel bars ...

[ 134 ] - Head-Driven Simulation of Water Supply Networks

Up to now most of the existing water supply network analyses have been based on demand-driven simulation models. These models assume that nodal outflows are fixed and are always available. However, this method of simulation neglects the pressure-dependent nature of demand that is characterized by changes in actual nodal outflows particularly during critical events like major mechanical or hydra...

[ 135 ] - Three New Systematic Approaches for Computing Heffron-Phillips Multi-Machine Model Coefficients (RESEARCH NOTE)

This paper presents three new systematic approaches for computing coefficient matrices of the Heffron-Phillips multi-machine model (K1, …, K6). The amount of computations needed for conventional and three new approaches are compared by counting number of multiplications and divisions. The advantages of new approaches are: (1) their computation burdens are less than 73 percent of that of convent...

[ 136 ] - The Neural Network Modeling Approach for Long Range Expansion Policy of Power Plant Ccenters

Traditionally, Electrical power plant capacities are determined after specific plant locations have been selected. In this paper an expansion policy of power plant centers involving the choice of regions that must be allocated to power plant centers and power plant centers capacities over a specified planning horizon (years) is tackled. The problem is performed as a mixed integerprogramming mod...

[ 137 ] - A Branch and Bound Method for Finding Flow Path Designing of Agv Systems (RESEARCH NOTE)

One of the important factor in the design of automated guided vehicle systems (AGVS) is the flow path design. This paper presents a branch-and-bound algorithm to determining the flow path by considering not only loaded-vehicles, but also empty-vehicles. The objective is to find the flow path, which will minimize total travel of loaded vehicles. We know that in branch-and-bound method a branch c...

[ 138 ] - Simulation of Styrene Polymerization in Arbitrary Cross-Sectional Duct Reactors by Boundary-Fitted Coordinate Transformation Method

The non-orthogonal boundary-fitted coordinate transformation method is applied to the solution of steady three-dimensional conservation equations of mass, momentum, energy and speciescontinuity to obtain the laminar velocity, temperature and concentration fields for simulation of polymerization of styrene in arbitrary cross-sectional duct reactors. Variable physical properties (except for speci...

[ 139 ] - Transient Natural Convection Flow on an Isothermal Vertical Wall at High Prandtl Numbers: Second-Order Approximation

The method of matched asymptotic expansions, which has been used in previous studies of steady natural convection flow, is extended here to transient natural convection flow at high Prandtl number (Pr). Second-order expansion solutions, valid for large Prandtl numbers, are presented for the transient natural convection flow near a vertical surface which undergoes a step change in temperature. T...

[ 140 ] - Control of Engineering Properties of Asphalt Concrete Based on Permanent Deformation Constraint of Subgrade at Tropical Zones in Iran (TECHNICAL NOTE)

The permanent deformation pavement of roads and streets at tropical zones Abstract (if layers are sufficiently compacted) is due to increase of asphalt layers temperature and consequential decrease of modulus of elasticity. Therefore, the asphalt mixture moves aside of the wheels of heavy vehicles and cause permanent deformations without volume variation. On the other hand, if the asphalt layer...

[ 141 ] - A Low Cost Sensorless Control Drive Circuit for of Low Voltage Switched Reluctance Motor

Shaft position sensing is an essential part of switched reluctance (SR) motor drive In order to synchronize the pulses of phase current with the period of rising inductance of the proper motor phase. Direct sensors such as, Hall effect and optical encoder are commonly used in SR motors. The purpose of this paper is to present an indirect shaft positioning sensing known as "sensorless " control ...

[ 142 ] - Dynamic Compensation of Electrical Power Systems Using Multilevel Voltage Source Inverter

A New Static Var Generator (SVG), using cascaded full-bridge inverters (FBI) with binary output levels and the parallel connections of two cascaded inverters by means of current sharing reactor in each phases is introduced. The new M-level inverter, where M is 2n+2 - 3, consists of only 2n single-phase full bridges for each phases. The proposed technique not only increases the current capacity ...

[ 143 ] - Forward Position Kinematics of a Parallel Manipulator with New Architecture

The forward position kinematics (FPK) of a parallel manipulator with new architecture supposed to be used as a moving mechanism in a flight simulator project is discussed in this paper. The closed form solution for the FPK problem of the manipulator is first determined. It has, then, been shown that there are at most 24 solutions for FPK problem. This result has been verified by using other tec...

[ 144 ] - Effect of Camber and Thickness on the Aerodynamic Properties of an Airfoil in Ground Proximity (RESEARCH NOTE)

A linear vortex panel method is extended to include the effect Abstract of ground proximity on the aerodynamic properties of two dimensional airfoils. The image method is used to model the ground effect . According to the results, lift coefficient of an airfoil may increase or decrease in ground effect based on a combinative effect of its camber, thickness, angle of attack and ground clearance....

[ 145 ] - A New Algorithm for Optimum Voltage and Reactive Power Control for Minimizing Transmission Lines Losses

Reactive power dispatch for voltage profile modification has been of interest Abstract to powerr utilities. Usually local bus voltages can be altered by changing generator voltages, reactive shunts, ULTC transformers and SVCs. Determination of optimum values for control parameters, however, is not simple for modern power system networks. Heuristic and rather intelligent algorithms have to be so...

[ 146 ] - Reducing the Limitation on Application of Synchronous Decorrelating Detector Cdma Systems

In CDMA (Code - Division Multiple - Access) systems multi - user accessing of a channel is possible. Under the assumptions of Optimum multi - user and decorrelating detector in CDMA systems. By using signals with zero and / or identical cross correlations, a simple and expandable decorrelating detector with optimum efficiency which can be easily implemented are proposed. Constructing these sign...

[ 147 ] - Hydrothermal Optimal Power Flow Using Continuation Method

The problem of optimal economic operation of hydrothermal electric power systems is solved using powerful continuation method. While in conventional approach, fixed generation voltages are used to avoid convergence problems, in the proposed algorithm, they are treated as variables so that better solutions can be obtained. The algorithm is tested for a typical 5-bus and 17-bus New Zealand networ...

[ 148 ] - On Two-Echelon Multi-Server Queue with Balking and Limited Intermediate Buffer

In this paper we study two echelon multi-server tandom queueing systems where customers arrive according to a poisson process with two different rates. The service rates at both echelons are independent of each other. The service times of customers is assumed to be completed in two stages. The service times at each stage are exponentially distributed. At the first stage, the customers may balk ...

[ 149 ] - Comaprison of Mass-Transfer Efficiencies of Scc and Structured Packing

In a previous paper, pressure drop, flooding and mass-transfer characteristics of a novel pilot-scale distillation column called spinning cone column (SCC) were presented. Here, we present the result of comparison of mass-transfer efficiencies of SCC and structured packing. Comparison of SCC and structured packing mass-transfer characteristics show that the gas and liquid-side height of transfe...

[ 150 ] - A Novel Data Compression Technique for 420 Ma Current Loop Transmitters

This paper presents a new data compression method for current loop transmitters. In this method, the 4-20 mA current domain is divided into some equal pieces that are used for distinct data domain with a constant relative resolution, resulting in widening the signal span. This technique eliminated the need for high resolution ADC’s or DAC’s in communication of 4-20mA current loop signals. Furth...

[ 151 ] - On Finite Queue with Two Types of Failures and Preemptive Priority (RESEARCH NOTE)

We study the single server queueing system with two types of Abstract failure to servicechannels including the preemptive priority to the repair of major failure. The units arrive at thesystem in a poisson fashion and are served exponenitally. The steady - state probabilities ofvarious states by using generating function have been obtained.

[ 152 ] - Prediction of Instability in Planar Anisotropic Sheet Metal Forming Processes

In this paper instability of planar anisotropic sheet metal during a few forming processes is investigated for the first time. For this reason components of the constitutive tangent tensor for planar anisotropic sheets are developed. By using the above tensor location of necking is predicted. Direction of the shear band is also predicted using the acoustic tensor. A finite element program is pr...

[ 153 ] - Analytic Solution for Hypersonic Flow Past a Slender Elliptic Cone Using Second-Order Perturbation Approximations

An approximate analytical solution is obtained for hypersonic flow past a slender elliptic cone using second-order perturbation techniques in spherical coordinate systems. The analysis is based on perturbations of hypersonic flow past a circular cone aligned with the free stream, the perturbations stemming from the small cross-section eccentricity. By means of hypersonic approximations for the ...

[ 154 ] - Robust Hybrid Motion Force Control Algorithm for Robot Manipulators

In this paper we present a robust hybrid motion/force controller for rigid robot manipulators. The main contribution of this paper is that the proposed hybrid control system is able to accomplish motion objectives in free directions and force objectives in constrained directions under parametric uncertainty both in robot dynamics and stiffness constraint constant. Also, the given scheme is prov...

[ 155 ] - A Numerical Method for the Determination of an Effective Modules for Coated Glass Fibers Used in Phenolic Composites

It is well known that the mechanical properties of fiberglass reinforced "phenolic moulding compounds" are significantly enhanced if the glass particles are coated with silane coupling agents before compounding. It has been shown that improvements obtained by using scanning electron microscopy techniques are due to better bonding of phenolic resin to the surface of treated glass fibers. These o...

[ 156 ] - Maximum Load and Minimum Volume Structural Optimization

A bi-criteria optimization is considered whose objectives are the maximization of the load sustained by a structure and the minimization of the structure's volume. As the objectives are conflicting, the solution to the problem is of the Pareto type. The problem is elaborated for a thin-walled column of cruciform cross-section, prone to flexural and torsional buckling. A numerical example is als...

[ 157 ] - Direct Numerical Simulation of the Wake Flow Behind a Cylinder Using Random Vortex Method in Medium to High Reynolds Numbers

Direct numerical simulation of turbulent flow behind a cylinder, wake flow, using the random vortex method for an incompressible fluid in two dimensions is presented. In the random vortex method, the primary variable is vorticity of the flow field. After generation on the cylinder wall, it is followed in two fractional time step in a Lagrangian system of coordinates, namely convection and diffu...

[ 158 ] - Dual Fuelling of a Direct Injection Automotive Diesel Engine by Diesel and Compressed Natural Gas

Application of Compressed Natural Gas (CNG) in diesel engines has always been important, especially in the field of automotive engineering. This is due to easy accessibility, better mixing quality and good combustion characteristics of the CNG fuel. In this study the application of CNG fuel along with diesel oil in a heavy duty direct-injection automotive diesel engine is experimentally investi...

[ 159 ] - Bioconversion and Enzymatic Activities of Neurospora Sitophila Grown Under Solid State and Submerged Fermentation on Sago Hamps (RESEARCH NOTE)

N.sitophila was grown under controlled conditions of solid state and submerged fermentation on Sago hampas. The optimum conditions of protein enrichment previously established for sugar beet pulp was used for this study. Under this condition the protein content of Sago hampas under solid state increased from 1.4 to 14.45% (W/W) whereas for Sago hampas and Sago starch, the protein content under ...

[ 160 ] - A New Iterative Fuzzy-Based Method for Image Enhancement (RESEARCH NOTE)

This paper presents a new filtering approach based on fuzzy-logic which has high performance in mixed noise environments. This filter is mainly based on the idea that each pixel is not allowed to be uniformly fired by each of the fuzzy rules. In the proposed filtering algorithm, the rule membership functions are tuned iteratively in order to preserve the image edges. Several test experiments we...

[ 161 ] - Signal Optimization During Radio Links Between a Transmitter and a Receiver Located in Adjacent Material Media with Differing Optical Densities (TECHNICAL NOTE)

Signal optimization is affected during radio links between a transmitter and a receiver located in adjacent material media with differing optical densities. The optimization is carried out via the automated control theory method. The radio signal obtained after the optimization is coordinated with the two media's electrical characteristics simultaneously; and this enables low power and small an...

[ 162 ] - Explicit Stiffness of Tapered and Monosymmetric i Beam-Columns

A formulation for finite element analysis of tapered and  monosymmetric I shaped beam-columns is presented. This is a general way to analyze these types of complex elements. Based upon the formulation, member stiffness matrix is obtained explicitly. The element considered has seven nodal degrees of freedom. In addition, the related stability matrix is found. Numerical studies of the aforementio...

[ 163 ] - a Simple Speed Control Technique and Pulsating Torque Elimination Method in a Brushless Dc Motor

This paper presents a theoretical derivation and computer simulation of an optimal speed controller for a brushless dc motor using feedback from a linear model running in parallel with the inverter-fed model. The intent of the feedback from the linear model is to eliminate torque ripples from the inverter drive. A nonlinear model of such a motor, transformed into a linear model by a local diphe...

[ 164 ] - Air-Fuel Ratio Control of a Lean Burn SI Engine Using Fuzzy Self Tuning Method

Reducing the exhaust emissions of an spark ignition engine by means of engine modifications requires consideration of the effects of these modifications on the variations of crankshaft torque and the engine roughness respectively. Only if the roughness does not exceed a certain level the vehicle do not begin to surge. This paper presents a method for controlling the air-fuel ratio for a lean bu...

[ 165 ] - Prediction of Major Pollutants Emission in Direct-Injection Dual-Fuel Diesel And Natural-Gas Engines

The dual-fuel diesel engine (D.F.D.E) is a conventional diesel engine in which much of the energy released, hence power, comes from the combustion of gaseous fuel such as natural gas. The exhaust emission characteristics of the D.F.D.E needs further refinements, particularly in terms of reduction of Unburnt Hydrocarbons (U7HC) and Carbon Monoxide (CO) emission, because the concentration of thes...

[ 166 ] - Dispersion Coefficients of Supercritical Fluid in Fixed Beds

The axial dispersion coefficient of hexachlorobenzene in supercritical carbon dioxide is investigated in a fixed-bed packed with glass beads. The on-line chromatographic pulse-response experiment is used in order to study the dynamics of a packed column under supercritical conditions. The radial dispersion is assumed negligible because of the packed column geometry. To estimate the axial disper...

[ 167 ] - Thermal Analysis of Shell-Side Flow of Shell-and-Tube Heat Exchanger Using Experimental and Theoretical Methods

In this paper the thermal behavior of the shell-side flow of a shell-and-tufe heat exchanger has been studied using theoretical and experimental methods. The experimental method Provided the effect of the major parameters of the shell-side flow on thermal energy exchange. In the numerical method, besides the effect of the major paramerers, the effect of different geometric parameters and Re on ...

[ 168 ] - Effects of Degree of Consolidation and Anisotropic Consolidation Stresses on Shear Modulus and Damping Ratio of Cohesive Soils at Low Strain

During consolidation process of saturated cohesive soil the soil stiffness increases. Increase of the effective stress due to dissipation of excess pore pressure causes additional stiffness of soil mass. This phenomenon has a very important effect on the behavior of saturated cohesive soils during dynamic loading. In the current investigation the changes in maximum shear modulus. Gmax and dampi...

[ 169 ] - on Minizing Mechanical Stresses of the Rail Way Wheels

The purpose of this paper is to study the behavior of elastic-plastic stresses under severe drag braking. A railway wheel performs three tasks, aiding in trian movement, supporting the car load, and acting as a brake drum. Finite element computer programs are developed for elasto-plastic stress analysis. An attempt is made here to find an improved fillet profile of the wheel with the intention ...

[ 170 ] - Prediction of Temperature Profile in Oil Wells

A mathematical model has been developed to predict the temperature distribution in wellbores either offshore or inshore. It is incorporated the different activities encountered during drilling operations. Furthermore, the effect of drill collar and casings and bit rotating in a well during completion has been considered. The two dimensional approach is presented in the form of a computer progra...

[ 171 ] - Influence of Operation Conditions Upon the Dynamic Steady State Performance of Switched Reluctance Motor

In order to obtain more accurate predicted dynamic steady-state performance with shorter computation time, an available mathematical model is modified and presented. Using this modified model, performance of a typical switched reluctance motor (SRM) under a wide range of variations of operating conditions is obtained and discussed. These include variations of speed, voltage, load and switching ...

[ 172 ] - Numerical Investigation of Combined Radiation and Nutral Convention Heat Transfer in a Horizonal Annulus

Combined radiation and natural convection within the annular region of two infinitely long horizontal concentric cylinders are investigated numerically in this research. Radial and tangential radiation effects ate considered using Milne-Eddington approximation for a two-dimensional radiative transfer. The basic conservation equations are discretized with the finite volume method and SIMPLER alg...

[ 173 ] - Machine Repair Queueing System with with Non-Reliable Service Stations And Heterogeneous Service Discipline (RESEARCH NOTE)

This investigation deals with M/M/R/N machine repair problem with R non-reliable service stations which are subjected to unpredictable breakdown. 1here is provision of an additional server to reduce backlog in the case of heavy load of failed machines. 1he permanent service stations repair the failed machines at an identical rate m and switch to faster repair rate when all service stations are ...

[ 174 ] - an Efficient Drive Circuit for Switched Reluctance Motor

The purpose of this paper is to present an efficient converter circuit used to drive switched reluctance motors. It uses the C-dump topology in which the trapped energy in the phase windings is returned to the supply capacitor to be used in the following strokes. In addition to the C-dump topology, it uses two extra feedbacks. One comes from a governor mounted on the shaft of motor which contro...

[ 175 ] - Reliability of Repairable System with Removable Multi-Repairmen

In this investigation, the explicit expressions for reliability function and mean time to failure (MTTF) of a repairable system with provision of spares and removable multi-repair facility have been established. In removable repairmen strategy, the repairmen turn on when there are N or more than N failed units and turn-off when system is empty. The failure times of operating/spare units and rep...

[ 176 ] - Corrosion of Concrete in Sea Water (RESEARCH NOTE)

Attack and disintegration of concrete structures under the influence of aggressive fluids, wet gases, etc. are understood as corrosion of concrete. The corrosion of concrete is a chemical, colloidchemical process, yet often a physico-chemical one, while that of reinforced concrete supported oil platforms are subjected to marine environment in the Persian Gulf and therefore corroded. In the pres...

[ 177 ] - Mechanism of Bainite Transformation in Fe-Cr-Mo-V-Ti-C Steel

The kinetics and mechanism of bainite transformation have been studied in Fe-Cr-Mo-V-Ti-C steel high speed dilatometry backed by thermodynamic analysis. The complete transformation of austenite, however, has not occurred at any reported temperature. Obtained results confirm the incomplete reaction phenomenon with the cessation of the bainite transformation well before the paraequilibrium is ach...

[ 178 ] - Mean Velocity and Static Pressure in a Sharp-edge Circular Nozzle Jet

An axisymmetric jet issued from a sharp edged circular convergent nozzle has been studied experimentally in the near field at Reynolds number 5.3x104  to search the saddle shape behavior of mean velocity and the role of mean static pressure in the jet flow. Due to the vena contracta effect the centerline mean velocity of the jet increases about 4.2% of its exit value and corresponding decrease ...

[ 179 ] - Elestoplastic Analysis of Barrier Pillars Above the Drifts in Inclined Seam (TECHNICAL NOTES)

In this paper, the effects of horizontal stress and dimensions of barrier pillars on the stability of drifts hr been investigated. An elastoplastic hybrid finite/boundary element program has been used. A plastic analysis of stresses in barrier pillars above the drifts in one of the underground coal mines with inclined seams is examined. Computed stresses and safety factor controur lines around ...

[ 180 ] - the Benefication Studies of Garnet Deposits From Kohe-E-Garbi Area of Iran (TECHNICAL NOTE)

The occurrences of huge reserves of garnet deposits have been reported from different parts of Iran specially those of Kohe-E-Gabri area which is very high grade in nature. These deposits can not be directly used as abrasives, filter aid and many others because of some impurities present. To know the mineralogical composition, the type of garnet, the shape of the particles, the chemical charact...

[ 181 ] - Elastic Initial and Post-local Buckling of Profiled through Girders

An experiment investigating the elastic local buckling response of trough girders composed of thin profiled steel sheeting has been undertaken Beam tests were performed to promote initial local buckling in a region of constant moment in the elastic range of structural response. The results of the experiments were compared with an elastic complex semi-analytical finite strip method of analysis, ...

[ 182 ] - Amorphous Silicon Flat Panel Imagers for Medical Application

A new gamma camera based on hydrogenated amorphous silicon (a-Si:H) pixel arrays to be used in nuclear medicine is introduced. Various performance characteristics of a-Si:H imagers are reviewed and compared with those of currently used equipment. An important component in the a-Si:H imager is the scintillator screen. A new approach for fabrication of high resolution CsI(Tl) scintillator layers,...

[ 183 ] - Range Distributions of Low-energy Nitrogen and Oxygen Ions in Silicon (RESEARCH NOTE)

The range distributions of low-energy nitrogen and oxygen (2-3 keV) ions is silicon are measured and compared with these available in theories. The nitrogen distribution is very close to a Gaussian distribution as predicted by theory. The oxygen profile however, indicates a surface localized peak along with a shoulder and a long tail into the sample. The surface peak is beleived to he the resul...

[ 184 ] - a Comparative Theoretical Analysis for a Knitted Loop Model

The theory presented in this paper differs from previous ones in that no arbitrary loop shape is assumed. Rather a strophoid curve, that is similar to knitted fabric Loop shape, has been assumed as the basic mathematical function. Additionally, the theory is improved by adapting buckled elastic rod theory, leading to a new equation from a certain mathematical curve. This loop model is assumed t...

[ 185 ] - A Review of the Control Techniques for Brushless Direct Current Motors (REVIEW PAPER)

This paper surveys the literature of the brushless DC motor speed control techniques. The paper should prove useful to both researchers as well as practising engineers as a signpost to the current state of the art. Based on the review some further studies are suggested.

[ 186 ] - Computation Optical Flow Using Pipeline Architecture

Accurate estimation of motion from time-varying imagery has been a popular problem in vision studies, This information can be used in segmentation, 3D motion and shape recovery, target tracking, and other problems in scene analysis and interpretation. We have presented a dynamic image model for estimating image motion from image sequences, and have shown how the solution can be obtained from a ...

[ 187 ] - Simulation of a Neutron Detector for Real Time Imaging Applications

Monte Carlo Method is used to simulate a double layer gadolinium-amorphous silicon thermal neutron detector. The detector fabricated in pixel array configuration has various applications including neutron imaging. According to the simulation results, a detector consisting of a gadolinium (Gd) film with thickness of 2-4 ~m, sandwiched properly with two layers of sufficiently thick (-30 ?µm) hydr...

[ 188 ] - Some Issues in Implementation of a Voltage Stability Analysis Function in an Energy Management System Environment

Over the last few years, the problem of voltage stability has received a lot of attraction from the power system community. This type of stability is now a major concern for utilities in both planning and operating conditions. Both static and dynamic aspects of the problem have been discussed and investigated by the researchers. The present paper concentrates on a Voltage Stability Analysis fun...

[ 189 ] - The Influence of Urban Network Features on the Quality of Traffic Service (RESEARCH NOTE)

The work reported here presents a methodology based on a two-fluid model to assess the degree of influence of various geometric and control features of an urban network on the quality of traffic service. The two-fluid model gives a curvilinear relation between the trip time and stop time per unit distance and its parameters characterize the quality of traffic service in urban networks. Any Chan...

[ 190 ] - The Effect to Epsilon Phase on the Friction and Wear of Nitrided Die Steels (RESEARCH NOTE)

In this paper, the wear resistance and antifriction of epsilon phase layer and diffusion layer of gas nitrided D2 steel and M2 steel have been studied. The changes m wear mechanism of epsilon phase under the load from 20N to 200N are analysed. When the load is lighter than 100N, it is mainly oxidizing wear on friction surface. The adhesion, peeling off and abrasive wear appear on friction surfa...

[ 191 ] - Advance Modelling and Simulation of Industrial Boilers

This paper presents some of the results of the simulation in the radiation section of an industrial boiler using an advanced mathematical model. Calculations are described for the flow, heat transfer, and chemical reaction processes occurring within a gas-fired cylindrical furnace. The calculation procedure is a two dimensional one in which the main hydrodynamic variables are the velocity and s...

[ 192 ] - Adaptive Line Enhancement Using a Parallel IIR Filter with A Step-By-step Algorithm

 A step-by-step algorithm for enhancement of periodic signals that are highly corrupted by additive uncorrelated white gausian noise is proposed. In each adaptation step a new parallel second-order section is added to the previous filters. Every section has only one adjustable parameter, i.e., the center frequency of the self-tuning filter. The bandwidth and the convergence factor of each secti...

[ 193 ] - Combined Radiation and Natural Convection in Participating Laminar Flow Over a Vertical Circular Pin

The interaction of thermal radiation with conduction and laminar natural convection in a vertical circular pin, situated at participating gas, is numerically investigated. An absorbing and emitting gas is considered, and treated to be a gray participating media. Under the idealizing of gray gas, the Rosselan4 approximation is employed to describe the radiative heat flux in the energy equation. ...

[ 194 ] - Prediction a of Tribocorrosion Wear Rate (RESEARCH NOTE)

Basic properties of the suggested phenomenological model of tribocorrosion wear are considered. Using a friction pair austenitic stainless steel-ceramic in acid electrolytes as an example, a good agreement between predicted data and experimental evidence was obtained.

[ 195 ] - Investigation of the Effect of Exhaust Gas Recirculation (EGR) on pollutants Emission From Si Engine Exhaust Gasese (RESEARCH NOTES)

This paper reports the results of an experimental investigation on the effect of the EGR on the pollutants emission, especially on oxides of nitrogen, from the exhaust gases and performance of the spark ignition engine. Also along with experimental work, a mathematical model for the determination of the effect of EGR on the peak cycle temperature and for the prediction of its effect on the NOx ...

[ 196 ] - Development of a Mathematical Model for Prediction of Pollutants Emission in D. I. Diesel Engines

Major pollutants emission from Direct-Injection (D.I) diesel engines are predicted by means of a mathematical model. In order to construct such a model, an integral Multi-Zone Combustion Model (MZCM) is formulated, which basically consists of jet mixing and combustion submodels. In MZCM, variation of injection pressure is considered. Also time period of ignition delay is predicted by considerin...

[ 197 ] - Appropriate Loading Techniques in Finite Element Analysis of Underground Structures

Stability of underground structures is assessed by comparing rock strength with induced stresses resulted from ground stresses. Rock mass surrounding the opening may fail either by fracture or excessive deformation caused. Accurate calculation of induced stresses is therefore fundamental in the stability analysis of an opening. Although numerical methods, particularly finite element method, are...

[ 198 ] - Rate of Pressure Rise in SI Engine Cylinder and its Relation to Knock (RESEARCH NOTE)

Tremendous efforts have been devoted to study the complex phenomenon "knock in spark ignition engines. There is an increasing interest in providing some tools to study knock in simulated data. In the previous studies, engine cylinder pressure oscillation has been used to investigate knock. Unless those methods involved highly complex non-detailed chemical relations, the previous studies were de...

[ 199 ] - Vibration of Road Vehicles with Non linear Suspensions

In order to investigate the effects of non-linear springs in vibrating behavior of vehicles, the independent suspension of conventional vehicles could be modeled as a non-linear single degree of freedom system. The equation of motion for the system would be a non-linear third order ordinary differential equation, when considering the elasticity of rubber bushings in joints of shock absorber. It...

[ 200 ] - A New Algorithm for the Deinterleaving of Radar Pulses

This paper presents a new algorithm for the deinterleaving of radar signals, based on the direction of arrival (DOA), carrier frequency (RF), and time of arrival (TOA). The algorithm is applied to classic (constant), jitter, staggered, and dwell switch pulse repetition interval (PRI) signals. This algorithm consists of two stages. In the first stage, a Kohonen neural network clusters the receiv...

[ 201 ] - A Numerical Study of Natural Convection and Radiation Interaction in Vertical Circular Pin

A numerical finite difference study has been earned out for two dimensional radiation-natural convection interaction phenomena in a vertical circular pin located at a non-participating (i.e. transparent) fluid. The coupled conservation equations in boundary layer (continuity, momentum, and energy equations) and pin energy equation are solved simultaneously using modified box method and fully im...

[ 202 ] - Beneflciation Studies of Bama Oxidized Lead and Zinc Ore

Bama is one of the major concentrating plant in Iran which treats nearly 1500 tons per day sulphidic lead and zinc ore. Large amount of oxidized ore exist in Bama which has been extracted along with sulphidic ore. The main objective of the present investigation was the up-grading of the ore from Goshfil which is the major deposit in Bama. The ore contained about 16% zinc as smithsonite, about 1...

[ 203 ] - Magnetic and Electerical Resistivity Behavior of Amorphous Ni Co P Films

Magnetic and Electrical Resistivity Study of Electroless Amorphous Ternary System (Ni-Co-P) show a qualitative dependence of crystalline phases formed during transformation on the annealing temperature and composition. Electrical Resistivity values increases with increase in cobalt content and samples with higher resistivity show lower temperature coefficients. The Initial increase in magnetiza...

[ 204 ] - A Mthod for Generating the Turbulent Intermittency Function

A detection method based on sensitization of a squared double differentiated signal is developed which discriminates the turbulent zones from laminar zones quite accurately. The procedure adopts a variable threshold and a variable hold time of the order of the Kolmogorov time scale. The output file so generated, includes all the information for further analysis of the turbulent signal.

[ 205 ] - Solubility of Hydrogen Sulfid and Sulfur Dioxide in Triethylen Glycol, Tetra Ethylene Clycol and Diethanol (TECHNICAL NOTE). AMINE SOLUTION

Natural gas sweetening is an important process which is used for treatment of sour gases. The measurement of solubility is also considered in most sweetening processes such as that of Townsend process. Therefore, experimental measurements would be helpful to determine the equilibrium data under actual equilibrium conditions for the gas treatment plants. In this research solubility of hydrogen s...

[ 206 ] - Glow Discharge Depth Profiling a Powerful Analytical Technique in Surface Engineering (TECHNICAL NOTE)

A variety of analytical techniques have been developed and employed to characterize the surfaces, subsurfaces and interfaces of surface engineering systems. They provide important information for quality control, process optimization and further development. Since the mid 1980's, glow discharge spectrometry (GDS) has emerged as an important and versatile technique for rapid depth profiling anal...

[ 207 ] - A Novel Disc-Type Reluctance Motor

This paper explores the theory and potential of a family of reluctance motors as well as brief review of different types of reluctance motors, motivated by the increased demands for geometric versatility and ruggedness for electric motors. This paper presents a new and novel disc type reluctance motor that has been designed built, tested, and analyzed. The magnetic circuit-based analysis shows ...

[ 208 ] - Wind Energy Estimation for Production of Electricity in Iran

This paper covers the estimation of the average yearly production of an appropriate wind turbine for different locations in Iran. The effects of topography, the influence of obstacles such as buildings and shelters, the collective effects of the surrounding terrain, roughness classifications, and orographic elements such as hills, cliffs, etc., all have been included in the calculations. A full...

[ 209 ] - Thermal Field Around a Circular Cylinder with Periodic Vortex Shedding

A numerical study is carried out to investigate the laminar forced convection heat transfer from a circular cylinder. The fluid is assumed to be incompressible, the Reynolds number ranged from 0.1 to 1000, and the Prandtl number was equal to 0.7. The range of study includes heat transfer in creeping flow (Re40). The equations were discretized by a control-volume-based finite difference techniqu...

[ 210 ] - A Composite Finite Difference Scheme for Subsonic Transonic Flows (RESEARCH NOTE).

This paper presents a simple and computationally-efficient algorithm for solving steady two-dimensional subsonic and transonic compressible flow over an airfoil. This work uses an interactive viscous-inviscid solution by incorporating the viscous effects in a thin shear-layer. Boundary-layer approximation reduces the Navier-Stokes equations to a parabolic set of coupled, non-linear partial diff...

[ 211 ] - Design and Fabrication of a Quartz Crystal Resonator Used in a Thickness-Monitor Unit (TECHNICAL NOTES).

This paper deals with the design and fabrication of a quartz-crystal resonator used in a thickness-monitor unit, measuring film thickness in a film-depositing system. A purpose-grown quartz crystal is cut to form the desired wafer. Two gold electrodes are deposited on both surfaces of the wafer to provide electrical contacts. The resonance frequency of the resonator, at room temperature, and th...

[ 212 ] - Preparation Zirconia Toughened Alumina by Deflocculation-Flocculation Route (TECHNICAL NOTE).

Partially stabilized zirconia (PSZ) agglomerate toughened alumina has been prepared by the "deflocculation-flocculation" technique, using 2 and 3 mol. % Y2O3-doped zirconia powders. Samples containing up to about 30 vol.% zirconia were obtained. The resulting microstructure seems to be mainly influenced by the physical properties of the starting powders, e.g. agglomerate size and the specific s...

[ 213 ] - The Study of Thermodynamic Surface and Contact Characteristics by a New Method of Simultaneous Thermooptical Analysis (TECHNICAL NOTES).

A device is described for studying thermodynamic and surface characteristics of metals as well as for differential thermal analysis of materials. A promise its shown is application for a multiple examination of high-temperature capillarity in a number of technological processes involving the formation or contribution of a liquid phase.

[ 214 ] - Analysis of Shaded Pole Induction Motors Considering Asymmetrical Flux Distribution and Saturation Effects

Several methods are available for performance prediction of single phase shaded pole induction motors. A simple model, in conjunction with a more complicated and accurate model, which considers the asymmetrical windings and core loss, is used to compare the prediction methods against experimental results. Saturation is incorporated in the model. Fundamental and harmonic flux density wave distri...

[ 215 ] - Bioreactor Scale-up for Water-Gas Shift Reaction

A scale-up study has been performed with three different size reactors to establish the optimum operating conditions for the hydrogen production from synthesis gas by biological water-gas shift reaction using the photosynthetic bacterium Rhodosprilliunt rubrum. Optimum medium composition and operating conditions previously determined in a bench scale 1.25 L continuous stirred tank reactor (CSTR...

[ 216 ] - Neural Network Implementation of a Three Phase Regulated PWM AC to Dc Convener with Input Unbalance Correction

Under unbalanced supply condition low order harmonics will appear at the input and output terminals of the PWM AC to DC converter. Based on the positive and negative sequence components, an unbalanced transfer matrix in terms of the input phase voltages is derived. An on-line method using a neural network (NN) is used to implement this transfer matrix. It is shown that by using an additional lo...

[ 217 ] - Rcd Rules and Power Systems Observability

Power system state estimation is a process to find the bus voltage magnitudes and phase angles at every bus based on a given measurement set. The state estimation convergency is related to the sufficiency of the measurement set. Observability analysis actually tests this kind of problem and guarantees the state estimation accuracy. A new and useful algorithm is proposed and applied in this pape...

[ 218 ] - Queue with Heterogeneous Server Under Resequencing Constraint

In this paper, a markovian queue with two types of servers and buffer space is considered. The resequencing constraint is imposed according to which the customers leave the system in the same order in which they entered it. For finite buffer queue, the steady state queue size distribution has been obtained.? 

[ 219 ] - Fluidization of Initialty Segregased Equidensity Binary System

Fluidization of initially segregated binary mixtures has been investigated for particle systems of the same material. This paper reports experiments conducted in 0.055m diameter fluidizes bed for binary mixtures composed of sands whose sizes ranged from 450 to 1450mm. An empirical relationship, Utf = 0.95 UF (dR)0.87, was derived in terms of the minimum fluidization of the smaller particle, UF ...

[ 220 ] - Simulation of a Variable Reluctance Steping Motor for Sinusoidal and Step Exitations

Steady-state dynamic simulation of a variable reluctance stepping motor is carried out by applying two different excitation voltages. First a single-step voltage is applied to the motor, and a sinusoidal voltage, as the first term of Fourier series of the single-step voltage, is then used as the input voltage of the motor. In both cases plots of machine torque, current and speed are presented. ...

[ 221 ] - Thermal -Hidraolyc Study of Trr Core in Fuel Conversion Frome Highly Enriched Uranium to Low Enriched Uranium Fuel (RESEARCH NOTES)

[ 222 ] - Quadtree and Octree Grid Generation

Engineering analysis often involves the accurate numerical solution of boundary value problems in discrete form. Hierarchical quadtree (or octree) grid generation offers an efficient method for the spatial discretisation of arbitrary-shaped two- (or three-) dimensional domains. It consists of recursive algebraic splitting of sub-domains into quadrants (or cubes), leading to an ordered hierarchi...

[ 223 ] - Natural Convection from a Helical Heating Coil to the Surrounding Fluid.

An experimental study is reported on natural convection heat transfer from a helical heating coil to the surrounding fluid. The coil is heated electrically and the surrounding fluid is selected to be water. The range of parameters are: Rayleigh number, 879 ?£ Ra ?£ 780168, Prandtl number, 4.22 ?£ Pr ?£ 10.02, dimensionless coil diameter,7.69 ?£ Dave /d ?£ 10.77, number of coil rings, 2 ?£ N ?£ ...

[ 224 ] - Contamination of the Konar Siah Karst Spring by Saltdom

There are about 200 salt plugs in the southern part of the Zagros Mountain Ranges and the Persian Gulf in Iran (Kent, 1970). The salt comes from the Hormuz salt Formation at the base of the Phanerozoic zone. It moves upward due to the buoyancy, the latteral pressure resulting from the opening of the Red Sea to the southwest, and the weight of several thousand meters of overlying sediments. It m...

[ 225 ] - Signal Design at lsolated lntersecaions Using Expert Systems Technology

The procedural steps for developing an expert system for designing signals at isolated intersections are described and the most important development issues for each step are discussed. The steps include problem analysis and definition, preliminary prototype specification, knowledge acquisition strategy development, prototype development plan, knowledge extraction, knowledge representation, too...

[ 226 ] - On Line Electric Power Systems State Estimation Using Kalman Filtering (RESEARCH NOTE)

In this paper principles of extended Kalman filtering theory is developed and applied to simulated on-line electric power systems state estimation in order to trace the operating condition changes through the redundant and noisy measurements. Test results on IEEE 14 - bus test system are included. Three case systems are tried; through the comparing of their results, it is concluded that the pro...

[ 227 ] - Intelligent Vehicle Highway Systems (Ivhs) Issues and Recommendations

Intelligent Vehicle Highway Systems (IVHS) is the integration of various pieces of information and computer technologies to the transportation elements in order to obtain a more productive transportation system. The five major components of IVHS are the Advanced Traffic Management Systems (ATMS), Advanced Vehicle Control Systems (AVCS), and Advanced Public Transportation systems (APTS). This pa...

[ 228 ] - Surface Hardness Measurment and Microstructural Characterisation of Steel by X-Ray Diffraction Profile Analysis

An X-ray diffraction line will broaden considerably when steels change into martensitic structure on quenching. The results presented in this paper show that X-ray diffraction technique can be employed for a rapid and nondestructive measurement of hardness of hardened steel. Measurement on various quenched and tempered steels showed that the breadth of its diffraction peak increased with increa...

[ 229 ] - Modified Enthalpy Method Applied to Laser Annealing of Semi Conductor Films

The rapid melting of silicon film due to the absorption of a CW laser beam radiation is studied. The silicon film melting and recrystallization is mainly controlled by the temperature distribution in the semiconductor. The enthalpy technique for the solution of phase change problems is used in an explicit finite difference form to calculate the transient temperature distribution in the silicon ...

[ 230 ] - Computer Simulation of Ammonia Cold Shot Converter

A mathematical model is developed and tested with plant data for the ammonia cold shot converter of Razi Petrochemical Complex. The model is based on a material and energy balance in a differential element of beds and is subjected to the assumptions of uniform distribution of temperature and composition through a general cross section and negligible mass and heat transfer in axial direction. Th...

[ 231 ] - Investigation of Melting by Molecular Dynamics Simulation

The melting of a 64 ion microcrystal of KCI was studied by means of a molecular dynamics computer simulation. We used a central pair interaction with an inverse power law repulsion. The thermodynamics, kinetic and structural properties such as melting temperature, latent heat, mean square displacement, diffusion constant, radial distribution function and bond angle distribution are calculated. ...

[ 232 ] - Stress Concentration Factors in Spherical Vessels with Single Oblique Nozzle

Finite element method is employed to analyze the spherical vessel intersected by an oblique cylindrical nozzle. In this survey the stress and strain distributions on acute and obtuse sides of the connection under internal pressure are studied widely although axial and moment loadings on the nozzle are also studied briefly. Stress concentration factors for a wide range of geometrical ratios in t...

[ 233 ] - Stress Analysis of the Human Ligamentous Lumber Spine-From Computer-Assisted Tomography to Finite Element Analysis

Detailed investigation on biomechanics of a complex structure such as the human lumbar spine requires the use of advanced computer-based technique for both the geometrical reconstruction and the stress analysis. In the present study, the computer-assisted tomography (CAT) and finite element method (FEM) are merged to perform detailed three dimensional nonlinear analysis of the human ligamentous...

[ 234 ] - Robot Motion Vision Part II: Implementation

The idea of Fixation introduced a direct method for general recovery of shape and motion from images without using either feature correspondence or optical flow [1,2]. There are some parameters which have important effects on the performance of fixation method. However, the theory of fixation does not say anything about the autonomous and correct choice of those parameters. This paper presents ...

[ 235 ] - The Gas Phase Oxidation of Acetaldehyde Reaction Mechanism and Kinetics

The mechanism of the low temperature oxidation of gaseous acetaldehyde was investigated in the temperature range of 1 50-400?°C. The minor, intermediate and major products were identified and measured quantitatively by sampling directly into the ionization chamber of an MS10-C2 mass spectrometer from the reactor. The formation of H2O, CO, CO2, HCOOH, H2, HCHO, CH3COOH and CH3OH as the major pro...

[ 236 ] - Robot Motion Vision Pait I: Theory

A direct method called fixation is introduced for solving the general motion vision problem, arbitrary motion relative to an arbitrary environment. This method results in a linear constraint equation which explicitly expresses the rotational velocity in terms of the translational velocity. The combination of this constraint equation with the Brightness-Change Constraint Equation solves the gene...

[ 237 ] - Optimum Design of Interbasin Pipe System (RESEARCH NOTES)

Pipe systems are often used to transfer moderate to medium water volumes between reservoirs or from well fields to consumers. Such systems consisting of an arbitrary number of reservoirs or other types of sources and sinks are considered here. The Lagrangean optimization principle is used for the determination of all pipe diameters giving minimum total cost of the system, when the individual di...

[ 238 ] - Accurate Prediction of Thermodynamic Properties of Alcoholes Ketones and Ethers by MCORGC Eos

This paper presents the ability of a new group contribution equation of state in the prediction of thermodynamic properties of alcohols, ketones and ethers. This equation of state, called MCORGC, is based on the Chain-Of-Rotators Group Contribution equation considering a NRTL type local composition mixing rule. The group parameters required to predict the thermodynamic properties of the oxygena...

[ 239 ] - On Line Identification of the First Markov Parameter of Linear Multivariable Plants (RESEARCH NOTE)

In this paper three methods for on-line identification of first markov parameter at linear multivariable plants are presented. In these methods input-output data are used far the on-line identification of the first markov parameter.

[ 240 ] - Theoretical Studies of Electrical Characteristics of the Nitrogen Laser

A theoretical analysis of the circuits for a nitrogen laser driven by the Blumlein or capacitor charge transfer transmission line is given in detail. The electrical characteristics of the charge line for a special case of resonant charging are discussed and the effects of various parameters on voltage and current are investigated. By using MICRO-CAP software the transient behavior of the curren...

[ 241 ] - Steep. Short-Crested Waves and Related Phenomena

Steep, short-crested waves, as well as a large variety of three-dimensional propagating wave patterns have been created in laboratory, utilizing a plunging half-cone. Monochromatic waves, over a range of frequencies and amplitudes through breaking and including soliton wave groups near resonance, have been observed and studied in a small wave flume. This monochromatic wavemaker creates complex ...

[ 242 ] - Tv and or Fm Transmitting Antennas Desien Using Computer Graphic System (RESEARCH NOTES)

The purpose of this paper is three fold. First, the major theoretical pattern relationships of TV and/or FM transmitting antennas are dealt with. Secend, the computer calculation method and designing of such patterns using the given relationships. And third, a method in which a computer graphic system can be used to design such antennas for a specific pattern is introduced and its results are p...

[ 243 ] - Moditication Factor for Sizing Equation of Electrical Machines-Single and Three Phase Induction Motors(RESEARCH NOTE)

Comparison between the results from the design procedure based upon the value of D2L (volume of iron) and IEC standard used by manufacturers indicates that the basic design equation of electrical machines must be modified by a proper modification factor. This modification factor is evaluated for single- and three-phase induction motors and its variation with motor rating and poles number is obt...

[ 244 ] - The Role of Aldehydes as Degenerate Branching Intermediate in the Oxidation of Hydrocarbons

The thermal oxidation of propane in the temperature range 350-425oC was studied in order to elucidate the role of higher aldehydes as degenerate branching intermediates in the oxidation of hydrocarbons. In the slow combustion of propane, the high yield of propylene and methanol as the primary products, the formation of hydrogen peroxide, carbon monoxide, carbon dioxide, formaldehyde and steam a...

[ 245 ] - Optimal Design of Geometrically Nonlinear Structures Under a Stability Constraint

This paper suggests an optimization-based methodology for the design of minimum weight structures with kinematic nonlinear behavior. Attention is focused on three-dimensional reticulated structures idealized with beam elements under proportional static loadings. The algorithm used for optimization is based on a classical optimality criterion approach using an active-set strategy for extreme lim...

[ 246 ] - Determining the Proper compression Algorithm for Biomedical Signals and Design of an Optimum Graphic System to Display Them (TECHNICAL NOTES)

In this paper the need for employing a data reduction algorithm in using digital graphic systems to display biomedical signals is firstly addressed and then, some such algorithms are compared from different points of view (such as complexity, real time feasibility, etc.). Subsequently, it is concluded that Turning Point algorithm can be a suitable one for real time implementation on a microproc...

[ 247 ] - Phase Only Synthesis of Antenna Patterns Using Iterative Restoration Methods

In this work, the method of iterative Fourier transform phase reconstruction, conventionally used in holography and optical image reconstruction, is applied to phase only synthesis of antenna patterns. The method is applied to two types of pattern synthesis problems: "main lobe beam shaping" and "side-lobe-level reduction". The proposed method is most useful in the efficient employment of attai...

[ 248 ] - Steady Flow Through Modeled Glottal Constriction

The airflow in the modeled glottal constriction was simulated by the solutions of the Navier-Stokes equations for laminar flow, and the corresponding Reynolds equations for turbulent flow in generalized, nonorthogonal coordinates using a numerical method. A two-dimensional model of laryngeal flow is considered and aerodynamic properties are calculated for both laminar and turbulent steady flows...

[ 249 ] - Dynamics of Flexible Manipulators

This paper presents an application of Continuum (i.e. Lagrangian) and Finite Element Techniques to flexible manipulator arms for derivation of the corresponding Dynamic Equations of Motion. Specifically a one-link flexible arm is considered for detailed analysis, and the results are extended for the case of a two - link flexible manipulator. Numerical examples are given for the case of both one...

[ 250 ] - Local Heat Transfer Coefficients in a Rectangular Duct with Plate Blockages of Variable Stream Wise Spacing

An experimental investigation is conducted to determine the effect of repeated-plate blockages of variable streamwise spacing on heat transfer characteristics of turbulent flow in rectangular ducts. The plates are attached to the upper and lower walls in a staggered arrangement. The experiments are carried out by mass transfer and the analogy between heat and mass transfer provides the necessar...

[ 251 ] - A General Boundary-Integral Formulation for Zoned Three-Dimensional Media

A new boundary-integral formulation is proposed to analyze the heat transfer in zoned three-dimensional geometries. The proposed formulation couples the boundary formula, the gradient of the boundary formula, and the exterior formula. An advantage of this formulation over the traditional methods is that any linear condition at the interface between subdomains may be incorporated into the formul...

[ 252 ] - On the Displacement-Stress Continuous Finite Elements

For the analysis of composite media, three different compatible and mixed finite element formulations are presented which apriori enforce the continuity of stresses as well as displacements at the element interfaces. The formulations are applied for the analysis of hi-material interfaces in two problems often encountered in the field of orthopaedic biomechanics, that is the fixation analysis in...

[ 253 ] - Reinforced Concrete Columns in Torsion (RESEARCH NOTE).

ACT does not suggest any regulations for columns under torsion. However, by all means, the number of such columns used in steel and concrete structures is abundant. In this paper, using the results of laboratory tests on 35 square and rectangular columns with intermediate slender ratios, relations for determination of torsional strengths of reinforced concrete under axial compression have been ...

[ 254 ] - a Simplified Model of Distributed Parameter Systems

A generalized simplified model for describing the dynamic behavior of distributed parameter systems is proposed. The various specific characteristics of gain and phase angle of distributed parameter systems are investigated from frequency response formulation and complex plane representation of the proposed simplified model. The complex plane investigation renders some important inequality cons...

[ 255 ] - Transient Minimization Within Static Var Compensated Distribution Systems

VAR support should be supplied as close to the load as possible to minimize transmission losses. For voltage control and for improvement of total power factor in a distribution system the circuit- breaker switched capacitor banks can be used. The problems with this solution are the voltage steps caused by the large sizes of the capacitor banks as well as the transients caused on insertion. Thyr...

[ 256 ] - A Studyof the Design of Horizontal Axis Wind Turbine

In this using paper a method is presented for the aerodynamic and structural analysis of a horizontal axis wind turbine using simplified methods. In the first part of the program the optimum rotor configuration for twist and chord is determined using the momentum and blade element theories for a rotor without coning or tilting and assuming zero drag average wind velocity. Then coning angle and ...

[ 257 ] - Mechanism and Prevention of Scale Formation in Boilers

Nucleate boiling heat transfer coefficients may be strongly reduced by scale formation, even for conditions where the bulk foulant concentration is well below the saturation concentration. Due to the mechanism of micro-layer evaporation, the local concentration at the heat transfer surface can be considerably increased, causing the formation of scale and changes in bubble frequency and bubble d...

[ 258 ] - Application of a One-Dimensional Computer Model to Flood Routing in Narrow Rivers

This paper deals with the development of a computer model for flood routing in narrow rivers. Equations describing the propagation of a flood wave in a channel-flood plain system are presented and solved using an implicit finite difference scheme. Particular emphasis has been given to the treatment of the friction term in the governing equation of motion.

[ 259 ] - Nonresonant Excitation of the Forced Duffing Equation

We investigate the hard nonresonant excitation of the forced Duffing equation with a positive damping parameter E. Using the symbolic manipulation system MACSYMA, a computer algebra system. we derive the two term perturbation expansion by the method of multiple time scales. The resulting approximate solution is valid for small values of the coefficient e As the damping parameter e increases, th...

[ 260 ] - A Non-Sinusoidal Reference Wave for Pwm Ac Drives

In this paper we propose a suitable reference wave for Pulse Width Modulation (PWM) AC Drives. Staircase reference waves whose levels are calculated to eliminate certain harmonics are studied and a certain staircase reference waveform with L levels is constructed. When L is made very large in limit, this staircase waveform approaches a continuous one which is called Quasine (Quasi + Sine). This...

[ 261 ] - Stochastic Synthesis of Drouths for Reservoir Storage Design (RESEARCH NOTE).

Time series techniques are applied to Ghara-Aghaj flow records, in order to generate forecast values of the mean monthly river flows. The study of data and its correlogram shows the effect of seasonality and provide no evidence of trend. The autoregressive models of order one and two (AR1, AR2), moving average model of order one and ARMA (1,1) model are fitted to the stationary series, where th...

[ 262 ] - The Effects of ZrO2 or Tic on the Performance of the Alumina-Based Ceramic Cutting Tools

Two types of alumina-based cutting tools with compositions of 90 vol.% Al2O3+10 vol.% ZrO2 and 80 vol.% A12O3+20 vol.% TiC are produced by isostatic pressing and sintering technique. The effects of these additives on the mechanical properties and cutting performance of these materials are investigated. The tool life in both materials is examined under identical conditions on cutting a grey cast...

[ 263 ] - Theoretical, Scientific and Practical Aspects of the Basic Stages of Cad Cam Designing of Centrifugal Pumps

Many theoretical and practical problems arise at different stages of the design/manufacturing process during development of a pump. The experience obtained in pump development proves that the quality of a pump depends on many factors, which should he satisfied to receive good results. At the same time, the theory of engineering design principles exists, which is applicable to designing various ...

[ 264 ] - Dual-Fuelling of a Direct-Injection Automotive Diesel Engine by Diesel-Gas Method

Use of liquefied petroleum gas (LPG) in compression-ignition (C-I) engines has always been considered important in the diesel engineering field. This is due to its easy accessibility and good combustion characteristics. In this paper the application of LPG fuel along with diesel oil in a direct- injection automotive diesel engine is experimentally investigated. In order to convert the pure dies...

[ 265 ] - Fundamental Solutions of Dynamic Poroelasticity and Generalized Termoelasticity

Fundamental solutions of dynamic poroelasticity and generalized thermoelasticity are derived in the Laplace transform domain. For poroelasticity, these solutions define the solid displacement field and the fluid pressure in fluid-saturated media due to a point force in the solid and an injection of fluid in the pores. In addition, approximate fundamental solutions for short times are derived by...

[ 266 ] - Recent Developments in Discrete Event Systems

This article is a brief exposure of the process approach to a newly emerging area called "discrete event systems" in control theory and summarizes some of the recent developments in this area. Discrete event systems is an area of research that is developing within the interstices of computer, control and communication sciences. The basic direction of research addresses issues in the analysis an...

[ 267 ] - Effect of Composition on the Recrystallization Behavior of if Steels During Simulated Hot Strip Rolling

Flow curves are generated in muti-pass torsion tests for a titanium stabilized and a niobium stabilized IF steel. Two types of test schedule are used, one based on plate rolling and the other approximating strip rolling. The purpose of the former is to define the three critical temperatures of steel rolling. The strip schedules are varied in order to investigate the influence of increasing the ...

[ 268 ] - Prediction of Fluid Flow and Heat Transfer Characteristics Behind a Single Backward-Facing Step

Numerical solutions based on standard finite volume method are presented for the study of heat transfer and fluid dynamic characteristics in turbulent flows behind a single sided backward-facing step. The calculation of the differential equations is performed using SIMPLE algorithm. For the turbulent quantities standard K-model is used. Predicted mean velocity profiles and reattachment lengths ...

[ 269 ] - Signal Prediction by Layered Feed - Forward Neural Network (RESEARCH NOTE).

In this paper a nonparametric neural network (NN) technique for prediction of future values of a signal based on its past history is presented. This approach bypasses modeling, identification, and parameter estimation phases that are required by conventional parametric techniques. A multi-layer feed forward NN is employed. It develops an internal model of the signal through a training operation...

[ 270 ] - Discussion of Road Accidents in Iran (SHORT COMMINUCATION).

Several comments are made regarding the recent papers by F. Ayati on road accidents in Iran.

[ 271 ] - Finite Element Methods for Convection Diffusion Equation

This paper deals with the finite element solution of the convection diffusion equation in one and two dimensions. Two main techniques are adopted and compared. The first one includes Petrov-Galerkin based on Lagrangian tensor product elements in conjunction with streamlined upwinding. The second approach represents Bubnov/Petrov-Galerkin schemes based on a new group of exponential elements. It ...

[ 272 ] - A Model of the Respiratory System in the Newborn Infant

A dynamic mathematical model is presented which successfully simulates the respiratory control system of the newborn infant in different physiological conditions. The primary objective in constructing this model has been to provide a simulation aid in the investigation of maturation of the respiratory system, and the respiratory disorders during the newborn period, without the need for invasive...

[ 273 ] - A Numerical Modeling for Natural Convection Heat Transfer in Porous Media With Generated Internal Heat Sources

In this paper a numerical method is used to study the unsteady state natural convection heat transfer within a confined porous media with uniform internal heat generation. The governing equations based on the Darcy model and Bossiness approximations are solved, using the finite difference Alternating Direction Implicit (ADI) method. The developed program was used to simulate natural convection ...

[ 274 ] - Influence of Altitude Atmospheric Pressure on Octane Requirement (RESEARCH NOTE).

The normal specifications of motor gasolines as well as their combustion characteristics in internal combustion engines are reviewed in this paper. The effective factors influencing the fuel performance, such as the molecular structure of the fuel constituents, the operating conditions and the atmospheric pressure and temperature are also discussed. A relationship between the optimum octane num...

[ 275 ] - Phase-Transformation of Gamma-Allumina to Alpha-Alumina as an Industrial Catalyst Support

The phase transformation of aluminum hydrates yields various forms of alumina (d, q, K) and eventually alpha-alumina. The decrease in the specific surface area of alumina upon heat treatment is due to changes in crystalline structure and hence a decrease in the porosity of the material, Although the conversion of gamma-alumina to alpha-structure takes place with a lowering in surface area and p...

[ 276 ] - Prediction of Thermodynamic Properties of Refrigerants in the Superheated Ragion

This paper demonstrates the capabilities of the PFGC-MES equation of state (EOS) for calculating the thermodynamic properties in the superheated region for pure refrigerants. In addition the ability of this EOS is also tested for predicting the VLE behavior of binary mixtures. For pure compounds several properties in the superheated region are predicted. The calculated results and the experimen...

[ 277 ] - A Database Model for Medical Consultation

The database model presented in this paper is suitable for application in which queries may require non-crisp references to certain attributes. The data item (attribute) values may be crisp or fuzzy. For instance, such adjectives as 'high' or 'normal' may be attribute values for the attribute blood pressure. A disease or a condition can be described by a number of symptoms which may be crisp al...

[ 278 ] - A Microprocessor-Based Hybrid Duplex Fault-Tolerant System

Reliability is one of the fundamental considerations in the design of industrial control equipment. The microprocessor-based Hybrid Duplex fault-tolerant System (HDS) proposed in this paper has high reliability to meet this demand although its hardware structure is simple. The hardware configuration of HDS and the fault tolerance of this system are described. The switching control strategies in...

[ 279 ] - Electrochemical Noise Analysis of Anaerobic (Bacterial) Corrosion of Steel

Corrosion of structural steel in an SRB containing environment for as long as 9 months, is studied using the Electrochemical Noise Analysis technique. The results show that the activity of the system, which was very low initially, started to increase after 6 months exposure to the environment. The power spectral density curves of the Electrochemical Potential Noise of the system, using the maxi...

[ 280 ] - An Adaptive Impedance Controller for Robot Manipulators

A desired dynamic behavior of constrained manipulators can be achieved by means of impedance control and various implementations of fixed controllers have been proposed. In this paper, and adaptive implementation is presented as an alternative to reduce the design sensitivity due to manipulator mismatch. The adaptive controller globally achieves the impedance objective for the nonlinear dynamic...

[ 281 ] - Minimizing the Mean Tardiness in A N1 Sequencing Problem

This paper considers the problem of minimizing the mean tardiness of N jobs when the jobs are scheduled on a single machine. A simple algorithmic procedure is develop to obtain an optimal or a near optimal sequence for the N jobs while considering an equal penalty cost incurred to each job delivered later than its due date. The developed algorithm is applied to the several test problems. The re...

[ 282 ] - Oxidative Coupling of Methane to Ethylene Over Sodium Promoted Manganese Oxide

Manganese oxide catalyst promoted with sodium and supported on silica exhibits fairly good activity and selectivity towards the synthesis of ethylene from methane at the optimum operating conditions. Methane and oxygen were fed into a tubular fixed bed reactor packed with catalyst under atmospheric pressure. The effects of temperature, residence time and feed composition on conversion, selectiv...

[ 283 ] - Dealloying and Stress Corrosion Craking of Copper Alloys in Cu(I) Solutions

Natural cases of dealloying or stress-corrosion cracking in copper alloys normally occur in oxygenated solutions, where the cathodic reactant is O2 or Cu2+. Within cavities or under deposits, the local environment is enriched in cuprous ions (e.g. CuCl2-, Cu (NH3)2+) and the potential is close to the Cu/Cu+ equilibrium. Such conditions can be simulated macroscopically by stirring powdered Cu2O ...

[ 284 ] - Earthquake Analysis of Spatial Rod Systems

A master element to be employed as a general spatial rod finite element is presented. This spatially curved and pretwisted element can have variable cross-section and variable curvature change. It may also be resting on an elastic foundation. Also, a finite element formulation for a general earthquake analysis of spatial rods is presented. The theoretical foundation has lead to a general-purpos...

[ 285 ] - An Experiment study concerning Natural convection frome a Horizontal Thin wire

An experimental investigation was carried out to determine heat transfer coefficients for natural convection from a heated horizontal wire. The heating is provided by electrical current, and the temperature of the wire is determined from the measurement of its resistance. The experiments are performed in three different convective environments: air, water, and oil. Prandtl number ranged between...

[ 286 ] - Real Time Dynamic Simulation of Power System Using Multiple Microcomputers

Recent developments in the design and manufacture of microcomputers together with improved simulation techniques make it possible to achieve the speed and accuracy required for the dynamic simulation of power systems in real time. This paper presents some experimental results and outlines new ideas on hardware architecture, mathematical algorithms and software development for this purpose. The ...

[ 287 ] - Construction of Deformation - Mechanism Maps for Metals and Solid Solution Alloys a New Approach

A new approach has been introduced to construct deformation-mechanism maps for metals and solid solution alloys. For this purpose two computer programs named DEFOR and GRAPH have been written in BASIC to be run on IBM compatible personal computers. Using these programs, deformation - mechanism maps for a number of pure metals and a solid solution alloy (Ti-6wt% Al) have been plotted and effects...

[ 288 ] - A Theoretical and Practical Study of Cracking of an Aluminium Alloy During Side Pressing Using a Finite - Element Analysis

Elastic-plastic finite-element analysis applied to metalforming allows the real macroscopic properties of the workpiece to be incorporated. This paper presents the results of an experimental study of the initiation of cracking in side-pressing of a heat-treated aluminium alloy (Duralloy 2014). Using an F. E. analysis, these are related to various fracture criteria. It is found that the criterio...

[ 289 ] - Core Loading Design for Bushehr Pressurized Water Reactor

The modified out-in fuel management strategy was applied to the core loading design for the first four cycles of the Bushehr (Iran-1) KWU designed Pressurized Water Reactor (PWR). The minimum peak-to-average power density was chosen as the objective function of the optimization process. Lattice homogenization and group constants generation were performed by using the LEOPARD computer code. For ...

[ 290 ] - Mathematical Model for Separation of Submicron Particles from Gas Stream in a Conduit Type Scrubber (RESEARCH NOTE).

A mathematical model has been developed for the prediction of the collection efficiency of submicron particles in the conduit type scrubber. The model has been tested with the data in the literature [1,3].

[ 291 ] - Improvement of Collapsibility of Sodium Silicate Bonded Cores for Aluminium Casting

This paper examines the compressive strength of sodium silicate bonded cores for aluminum casting with different additives. Various materials are used as additives among which it is found that 5% sand size bauxite has the best effect on both gas strength and de-coring 98.5% silica content sand with 70-90 AFS No. with 4% sodium silicate is used. The results indicate that although very good colla...

[ 292 ] - Solidification in Copper Continuously Cast in Graphite Moulds

A mathematical model of heat transfer in continuous casting copper slabs capable of producing experimental data has been constructed and validated against experimental data provided by the management of Copper Refineries Ltd., Townsville plant in Australia. It has been used to predict the effects of major casting variables; metal temperature, casting speed and metal conductivity. The results ca...

[ 293 ] - Prediction of Temperature Profile of a Buried Gas Pipeline Through Utilization of Corresponding States Principle

A new analytical equation for prediction of temperature profile of a buried gas pipeline is developed. Utility of this equation is illustrated by its application to corresponding states principle. The resulting equation is tested through prediction of the actual Schorre data. It is shown that the new equation can predict temperature profile more accurately than the others without using any char...

[ 294 ] - Molecular Dynamics Simulation of Potassium Chloride Melting(.I. Microcrystal Simulation and Sample Size Effect)

The effect of sample size on the melting parameter of simulated potassium chloride microcrystal is investigated by molecular dynamics simulation. The size of microcrystal is varied from 8 to 4096 ions. The increase in melting temperature with sample size was found to be in good agreement with the theory.

[ 295 ] - Molecular Dynamics Simulation of Potassium Chloride Melting (II. Constant Volume and Constant Pressure Simulation of Filled System)

We have used a simple ionic potential to simulate the melting of KCI pseudo-infinite crystal. Two MD simulations, one with constant Volume and the other with constant pressure condition are performed. These results are compared with the previous micro-sample simulation results. In the constant volume simulation the melting temperature increase substantially with increasing pressure. A method fo...

[ 296 ] - New Methods for Harmonic Reduction in T. C. R. by Sequence Control of Transformer Taps

Thyristor controlled static compensators consist of two basic schemes, TCR and TSC. Owing to the discontinuous current in TCR, current harmonics are generated in the supply system. This paper introduces two methods for the reduction of these harmonics. On the basis of the coordination or uncoordination of turn ratios with harmonic reduction levels, each method is described in two alternative sc...

[ 297 ] - Enhancement of Natural Convection Heat Transfer in Annular Enclosures

Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105  to 5 x 106...

[ 298 ] - Computer Simulation of Hydrodynamic Behavior of Aggregative Fluidized Beds

Hydrodynamic behavior of aggregative fluidized beds has been studied and a model proposed for the prediction of different characteristics of fluidized beds. According to this model, a computer program is prepared and the hydrodynamic behavior of some industrial units has been simulated.

[ 299 ] - The Pfgc Equation of State at the Age of Fourteen

The purpose of this paper was to review and report the recent advances and progress that have been achieved on the fourteen year old PFGC equation of state. This paper will also discuss the good (pros) and the bad (cons) of this equation of state. Emphasis will be made on the following categories:A. Prediction of the pure component PVT properties1. Hydrocarbons in particular n-alkanes2. Selecte...

[ 300 ] - A Microcomputer-Based Simulator for Digital Control Systems

A microcomputer-based simulator for digital control systems is proposed. The proposed simulator is a hybrid system in which the plant is simulated by conventional method of analog computers and other parts of the system including generation of input signal is performed digitally, using a Z-80 based microcomputer. To overcome the difficulty of programming in assembly language, and at the same ti...

[ 301 ] - Connectivity as a Measure of Power System Integrity

Measures of network structural integrity useful in the analysis and synthesis of power systems are discussed. Signal flow methodology is applied to derive an expression for the paths between sources and sinks in a power network. Connectivity and reach ability properties of the network are obtained using the minors of a modified connectivity matrix. Node-connectivity, branch connectivity and mix...

[ 302 ] - Longitudinal Conduction in Cross Flow Heat Exchanger with Condensation

The deterioration of the performance of a cross flow heat exchanger with condensation due to the longitudinal conduction was investigated. For a relatively small change of wall temperature along the flow directions which was shown to be common in many applications, the energy equations were solved numerically. An iterative method was used to solve the resulting equations of the finite differenc...

[ 303 ] - Resurgent Cauldrons and Their mineralization between Narigan, Esfordi, Kushk, and Seh Chahoon, Central Iran

[ 304 ] - The Potentiodynamic Behavior of Copper in NaCI Solutions Studied by Auger and Photoelectron Spectroscopy

The potentiodynamic behaviour of copper in brine solutions was studies. Auger and photo-electron spectroscopy were used together with electrochemical methods. It is demostrated that the passivation observed in potentiodynamic curves is due to a surface film formation on a copper electrode. It is concluded that this film must be copper (I) chloride in nature. Effect of different factors on poten...

[ 305 ] - The Kinetics of Methanation on Nickel Catalysts

An empirical rate equation was obtained for the methanation kinetics catalyzed by MCR-2X, a commercial catalyst prepared by Haldor-Topsoe. The studies were carried out in a fixed-bed reactor under differential conditions, and in a gradientless recycle reactor (Berry) over a range of total pressures, reactant concentractions (H2/CO ratios), and temperatures. The kinetics of methanation were foun...

[ 306 ] - Stiffness Matrices for Axial and Bending Deformations of Non-Prismatic Beams with Linearly Varying Thickness

Siffness matrices for axial and bending deformations of a beam having a rectangular cross sectional area of constant width and linearly varying thickness are developed. A consistant load vector for a uniformly distributed lateral load is also calculated, using the principal of potential energy. The matrices are used to obtain numerical results for a variety of beams with non-uniform thickness t...

[ 307 ] - Harmonic Response of Pile Groups to Dynamic Loading

A completely general method of analysis for three-dimensional raked piles under harmonic excitation is discussed. The piles have been represented by a three-dimensional frame structure and the soil has been represented by a boundary element discretization scheme. A computer program has been written which carries out this analysis and produces a group stiffness matrix that can be included as a f...

[ 308 ] - Modeling and Performance Evaluation of Multi-Processors Organization with Shared Memories

This paper is primarily concerned with theoretical evaluation of the performance of multiprocessors system. A markovian waiting line model has been developed for various different multi-processors configurations, with shared memory. The system is analysed at the request level rather than job level.