Selection of optimal heat sink dimensions using evolutionary strategies: A case study

Umar Khan, Liaquat Ali Khan and Syed Zahid Hussein

The ever rising transistor densities and switching speeds in microprocessors have been accompanied a dramatic increase in the system heat flux and power dissipation. In this context the rising IC densities combined with even more stringent performance and reliability requirement have made thermal management issues ever more prominent in the design of sophisticated microelectronic systems. In order to achieve a higher degree of power dissipation extruded heat sinks have been a standard for many years.  The objective of this paper is to use an evolutionary optimization method for the determination of the optimal heat sink dimensions, such that the optimized dimensions are within realistic manufacturing constraints and the heat dissipation capability is maximized.

Determination of volume fraction values of filament wound glass and carbon fiber reinforced composites

Abdalla F. H., Megat M. H., Sapuan M. S. and B. B. Sahari

With the expansion of composites into application like pipes and pressure vessels, there exists a need for further studies on the properties of these materials. This paper presents the results from a series of tests on the physical properties of composite materials. Specimens cut from pipes made from composite materials to be tested under internal pressure loadings have been tested by using a series of ASTM D2584 (1968) standards test methods for glass fiber reinforced composites and the density method for carbon fiber reinforced composites. The results from this series of tests have been tabulated and presented. The volume fraction for the glass and carbon fibers were found to be 0.476 and 0.540, respectively.

Fuzzy and ANFIS based soft starter fed induction motor drive for high performance applications

L. Rajaji, C. Kumar and M. Vasudevan

Soft starters are used with induction motors in blowers, fans, pumps and the crane hoist drives. AC voltage controllers are used as soft starters in induction motors for starting and to adjust its speed. This paper highlights the intelligent controllers such as Fuzzy and Neuro fuzzy based ac voltage controllers to generate the firing pulses for appropriate thyristors for any given operating torque, speed of the motor and the load. FUZZY and ANFIS (Adaptive Neuro Fuzzy Inference System) models have been designed to achieve the proposed algorithm. MATLAB/SIMULINK package was used to simulate the proposed methods. Simulation results presented in this paper explain the advantages of proposed soft starting methods over conventional method. The advantages of intelligent methods proposed in this paper are its simplicity, stability, accuracy and fast response.

Finite element modeling of stress distribution in the cutting path in machining of discontinuously reinforced aluminium composites

Raviraj Shetty, Laxmikant K.1, R. Pai and S. S. Rao

One focus of this paper is to highlight issues on machining of discontinuously reinforced aluminium composites (DRACs), due to the complex deformation and interactions among particles, tool and matrix it is often unable to explore the behavior by an experimental or analytical method. This paper investigates the stress distribution in particles along, above and below cutting path under different cutting speed and constant depth of cut using finite element method. The development of stress fields in the DRACs was analyzed and physical phenomena such particle de-bonding, displacements and inhomogeneous deformation of matrix material were explored. It was found that tool-particle interaction and stress distributions in the particles/matrix are responsible for particle de-bonding and surface damage during machining of DRACs.

Study of flank wear in single point cutting tool using acoustic emission sensor techniques

S. Sundaram, P. Senthilkumar, A. Kumaravel and N. Manoharan

Wear of a cutting tool in a machining operation is highly undesirable because it severely degrades the quality of machined surfaces and causes undesirable and unpredictable changes in the work geometry. From a process automation point of view, it is therefore necessary that an intelligent sensing system be devised to detect the progress of tool wear during cutting operations so that worn tools can be identified and replaced in time. As a ‘non – destructive’ sensing methodology, Acoustic Emission (AE) based techniques offer some advantages over force or power based tool monitoring techniques because of the close relationship between the generation of the emission signal and the fracture or wear phenomenon in machining. The generation of the AE signals directly in the cutting zone makes them very sensitive to changes in the cutting process. Acoustic Emission Techniques (AET) is a relatively recent entry into the field of Non – Destructive Evaluation (NDE) which has particularly shown very high potential for material characterization and damage assessment in conventional as well as non-conventional processes. This method has also been widely used in the field of metal cutting to detect process changes like tool wear etc. In this research work the results obtained from the analysis of Acoustic Emission sensor employs to predict flank wear in turning of C45 steel of 250 BHN hardness using Polycrystalline diamond (PCD) insert. The correlation between the tool wear and AE parameters is analyzed using the experimental study conducted in 5 H.P all geared lathe.

Reverse engineering: point cloud generation with CMM for part modeling and error analysis

Manzoor Hussain M., Sambasiva Rao CH. and Prasad K. E.

Abstract:

From many decades reverse engineering (RE) has been used to make duplicate parts and part drawing prints in military and defence sectors. Scientific literature presents many different approaches for implementation of reverse engineering. Most of the studies are based on the analysis of point clouds acquired through coordinate measuring devices, such as, Coordinate Measuring Machines (CMMs), Optical Scanners or Interferometric Systems. In recent years, the development of computer technology resulted in the integration of design and manufacturing systems and automated inspection/gauging systems in manufacturing engineering applications. Geometrical information of a product is obtained directly from a physical shape by a digitizing device, from this complete 5-axis tool-path is obtained. Duplicating the part is done with the help of CMM and CAD/CAM software like   Mastercam, ProEngineer etc. CMM is used to digitize the mechanical object. Taking coordinates (scan data) of the various points on the surface of the object and converting it into IGES file and using the same in the CAD/CAM software with required interfacing creates a surface or solid model of the object. Finally this solid model is used to generate CNC part program to manufacture the part on CNC Machining center.

Molecular interaction studies in the ternary liquid mixture of Pyridine + Benzene + N, N-Dimethylformamide by ultrasonic velocity measurements

AN Kannappan, R. Kesavasamy and V. Ponnuswamy

Effect of pile cap system on the distribution of bending moment of cap

Jasim M Abbas, Zamri Hj Chik and Mohd Raihan Taha

Abstract:

The present paper undertakes the analysis of pile-cap system under the assumption of continuo piles-pile-cap connection. The piles are simulated by means of springs of varying stiffness. Nonlinearity of the piles was treated under the assumption of a hyperbolic stress-strain relationship. The pile cap was assumed as plate elements. The analysis conducted in this study is the moment distribution within the cap. Comparison was made for distribution under a constant stiffness and varying stiffness assumptions. The effect of pile cap stiffness on bending moment was demonstrated for the analysis. The distribution of bending moments along the two considered sections for cap thickness of 3m, the piles are assumed to have linear behavior. The bending moments have the lowest value at the ends of sections. The bending moment increased when moving towards the center of cap until reaching the maximum value. For pile thickness of 1.0m to 4.0m, the maximum bending moment was found to be located between center line of the pile cap and edges. The maximum bending moments increased with increase in the thickness of the pile cap. The effect of pile cap thickness on the distribution of bending moment is also presented in this paper.

Semicircular microstrip low pass filter

Kumud Ranjan Jha and Manish Rai

Abstract:

A loop based load flow method for weakly meshed distribution network

S. Sivanagaraju, J. Viswanatha Rao and M. Giridhar

Abstract:

A distinctive load flow solution technique is proposed for the analysis of weakly meshed distribution systems. The special topological characteristics of distribution networks have been fully exploited to make the solution possible. A branch-injection to branch-current matrix is formed (BIBC). This matrix is obtained by applying Kirchhoff’s current law for the distribution network. Using the same matrix a solution for weakly meshed distribution network is proposed. Bus voltages are found by forward-sweep of the network. Test results of 33-bus and 69-bus systems are given to illustrate the performance of the proposed method.

Design of intelligent hybrid controller for swing-up and stabilization of rotary inverted pendulum

Melba Mary P. and Marimuthu N. S.

Abstract:

A hybrid controller for swinging up rotary inverted pendulum is proposed in this paper. The controller composes of two parts. The first part is the PD position control to swing up the pendulum from its hanging position by moving the rotary arm clockwise and anticlockwise repeatedly until the pendulum swings up around the upright position. The second part is a Fuzzy Logic Controller which will be switched to balance and stabilize the pendulum at its upright position. State feed back control designed by LQR is also done for stabilization of the pendulum. The proposed intelligent hybrid controller is compared with the conventional controller; the effectiveness and reliability are shown by the simulation results.

Determines efficiency of the Iranian iron ore industries

Gorabian Yazdi Nader

Abstract:

Bafq iron ore producers had faced no competition from foreign iron ore in the Bafq steel market for nearly a century as the 1970s closed. In the early 1980s, as a result of unprecedented developments in the world steel market, Brazilian producers were offering to deliver iron ore to Chicago (the heart of Bafq market) at prices substantially below local iron ore prices. The Iranian iron ore industries faced a major crisis that cast doubt on their future. In response to the crisis, these industries dramatically increased productivity. Labor productivity doubled in a few years (whereas it had changed little in the preceding decade). Materials productivity increased by more than half. Capital productivity increased as well. We show that most of the productivity gains were due to changes in work practices. Work practice changes reduced overstaffing and hence increased labor productivity. Changes in work practices, by increasing the fraction of time equipment was in operating mode, also significantly increased materials and capital productivity.

Experimental characterization of filament wound glass/epoxy and carbon/epoxy composite materials

A. F. Hamed, M. M. Hamdan, B. B. Sahari and S. M. Sapuan

Abstract:

Composites have been used extensively in application such as pipes and pressure vessels. Therefore there is a need for further studies on the properties of these materials. This paper presents the results from a series of tensile tests on the mechanical properties of composite materials. Specimens cut from pipes made from composite materials were tested under internal pressure loadings have been tested by using a series of ASTM Standards test methods for mechanical properties. Based on the results obtained, the longitudinal E11, transverse E22 and shear modulus G12 of 101.2 GPa, 5.718 GPa, 4.346 GPa and 36.6, 5.4 GPa, 4.085 GPa for carbon and glass fiber/epoxy composites, respectively, while the ultimate longitudinal XL, transverse XT and shear tensile τ0 strengths of 1475.4 MPa, 20 MPa, 36 MPa and 618.9 MPa, 14 MPa, 28 MPa for carbon and glass fiber/epoxy composites, respectively. The results from this series of tests have been presented and compared with results from analytical equations. Good agreement was achieved between the experimental results and analytical results.

Performance evaluation of a single cylinder four stroke petrol engine

Asif Ali Mirani, Jandool Khan, Saeed Ahmed Solangi and Ali Akbar Channar

Abstract:

A research study on evaluation of performance of a single cylinder four stroke Otto engine was conducted. The actual size of engine parameters like bore, stroke, swept volume, clearance volume, compression ratio and r.p.m. were recorded and computed. Based on the actual size of the engine parameters the indicated horse power (ihp), brake horse power (bhp) and friction horse power (fhp) was determined and were found to be 1.54, 1.29 and 0.25, respectively. The mechanical efficiency and thermal efficiency was also calculated and were found to be 83% and 20.5%, respectively. The fuel consumption per hour was found to be 0.8 liter/hour while the fuel consumption per distance traveled was found to be 60 km/liter.