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Title: Wear Characteristics of Ultra-Hard Cutting Tools when Machining Austempered Ductile Iron
Author(s): Ashwin Polishetty, Moshe Goldberg, Guy Littlefair
Pages: 1-6 Paper ID: 106101-8787-IJMME-IJENS Published: February, 2010
Abstract: Nodularised Ductile Cast Iron, when subjected to heat treatment processes – austenitising and austempering produces Austempered Ductile Iron (ADI). The microstructure of ADI also known as “ausferrite” consists of ferrite, austenite and graphite nodules. Machining ADI using conventional techniques is often a problematic issue due to the microstructural phase transformation from austenite to martensite during machining. This paper evaluates the wear characteristics of ultra hard cutting tools when machining ADI and its effect on machinability. Machining trials consist of turning ADI (ASTMGrade3) using two sets of PCBN tools with 90% and 50% CBN content and two sets of ceramics tools; Aluminium Oxide Titanium Carbide and Silicon Carbide – whisker reinforced Ceramic. The cutting parameters chosen are categorized as roughing and finishing conditions; the roughing condition comprises of constant cutting speed (425 m/min) and depth of cut (2mm) combined with variable feed rates of 0.1, 0.2, 0.3 and 0.4mm/rev. The finishing condition comprises of constant cutting speed (700 m/min) and depth of cut (0.5mm) combined with variable feed rates of 0.1, 0.2, 0.3 and 0.4mm/rev. The benchmark condition to evaluate the performance of the cutting tools was tool wear evaluation, surface texture analysis and cutting force analysis. The paper analyses thermal softening of the workpiece by the tool and its effect on the shearing mechanism under rough and finish machining conditions in term of lower cutting forces and enhanced surface texture of the machined part.
Keywords:ADI, Cutting force analysis, Surface texture analysis, Tool wear analysis.
Full Text (.pdf)  International Journals Of Engineering and Science | 563 KB
Title: Temperature Profile and Thermocline Thickness Evaluation of a Stratified Thermal Energy Storage Tank
Author(s): Joko Waluyo, M. Amin A. Majid
Pages: 7-12 Paper ID: 108601-2424-IJMME-IJENS Published: February, 2010
Abstract: Determination of thermocline thickness requires a continuous profile of temperature distribution. Difficulty in determining thermocline thickness arises for the case of discrete temperature data, since the profile formed could not be used to estimate the thermocline thickness. This paper discusses a practical method for formulation of thermocline thickness of stratified thermal energy storage. Curve fitting by iterative method was adopted to identify the functions which could represent the S-curve of temperature distribution. Based on the functions, thermocline thickness was formulated using functional relationship of temperature profile. Results identified two functions which could represent S-curve of temperature distribution, namely sigmoid dose response (SDR) and four parameter sigmoid (FPS) functions. Both functions were observed to well fit the temperature distributions having coefficient determination more than 0.99. Based on evaluations the formulations were capable to be utilized for evaluation of thermocline thickness of the stratified TES. The methods offer an advantage to obtain an exact value of thermocline thickness.
Keywords:Temperature distribution profile, thermocline thickness, Stratified thermal energy storage.
Full Text (.pdf)  International Journals Of Engineering and Science | 351 KB
Title: Design, Fabrication and Experimental Study of a Novel Two-Axis Sun Tracker
Author(s): M. R. I. Sarker, Md. Riaz Pervez, R.A Beg
Pages: 13-18 Paper ID: 105501-3939-IJMME-IJENS Published: February, 2010
Abstract: This paper presents the design, construction and also investigates an experimental study of a two axis (azimuth and Polar) automatic control solar tracking system to track solar PV panel according to the direction of beam propagation of solar radiation. The designed tracking system consists of sensor and Microcontroller with built in ADC operated control circuits to drive motor with control software, and gear- bearing arrangements with supports and mountings. A digital program operates the designed Sun tracker in the control system. Two steeper motors are used to move the system panel, keeping the sun’s beam at the center of the sensor. To investigate the effect of using two-axis sun tracking systems on the electrical generation of a flat photovoltaic system (FPVS) an experimental study is carried out to evaluate its performance under local climate. The measured variables are compared with the fixed axis.  The results indicate that the energy surplus becomes about (30- 45%) with atmospheric influences. In case of seasonal changes of the sun’s position there is no need to change in the hardware and software of the system. .  Considering all above aspects of this tracking system it can be concluded that, it is a flexible tracking system with low cost electromechanical set-up, low maintenance requirements and ease on installation and operation.
Keywords: Microcontroller, Solar energy, Sensor, Stepper motor, Two-axis solar tracker.
Full Text (.pdf)  International Journals Of Engineering and Science | 469 KB
Title: The Effect of the Trajectory of Javelin Thrower's Upper Limb on the Muscles, Ligaments, and Reaction Forces at Elbow Joint
Author(s): A. A. Mohamed, K. T. Mohamedb, E. M. Attia, T. H. Awad
Pages: 19-22 Paper ID: 105701-3636-IJMME-IJENS Published: February, 2010
Abstract: Our understanding of athletic and sports injuries, and sports medicine has grown immensely as we have become more aware of the importance of exercise and team sports. With the increased number of sports and games played, the risk of injury and the number of people affected have increased. Athletic injuries can occur when an individual is careless, or not fit enough to undertake sports and games. In some cases people become injured during the use of sports equipment. Athletic injuries result from over stress put on bones or muscles. Most common injuries are soft tissue; muscles, tendons, and ligaments injuries. Also, a dislocation occurs when two bones are jolted apart at a joint and is often accompanied by a ligament tear in the joint. In this study, a three-dimensional dynamic model analysis of the human elbow joint during javelin throw has been developed. The model was used to compare between the muscle, ligament, and reaction forces at the human elbow region of two athletes; a professional one and a beginner. The effect of the trajectory of the thrower's upper limb on the distance and on the muscles forces, ligaments forces, and reaction forces was investigated. The javelin throw distance recorded for the professional subject was as twice as that recorded for the beginner subject. The model results showed that the professional subject mainly depended on the upper limb major muscles to achieve his longer throw, while the beginner subject did not, mainly, depend on these muscles. In summary, identification of root causes, either in techniques or training programs, will minimize injury recurrences. The presented model may help in choosing the right techniques or training programs by which injuries, for human elbow joint, can be avoided or at least can be minimized.
Keywords: Elbow joint; Javelin throwing; Muscle forces.
Full Text (.pdf)  International Journals Of Engineering and Science | 469 KB