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Mechanical Engineering

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Faculty of Engineering University of Malaya

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Fuzzy Logic-Based Approach To Investigate The Novel Uses Of Nano Suspended Lubrication In Precise Machining Of Aerospace Al Tempered Grade 6061 Feb 2015

Fuzzy Logic-Based Approach To Investigate The Novel Uses Of Nano Suspended Lubrication In Precise Machining Of Aerospace Al Tempered Grade 6061

Faculty of Engineering University of Malaya

Temper-grade aluminum alloy Al-6061-T6 is commonly used for many engineering purposes owing to its superior mechanical properties. Due to the practical importance, machining Al-6061-T6 alloy is crucial for different applications. The development of computer numerical control (CNC) of milling machines is in progress by researchers worldwide for its noteworthy advantages. The quality of machining determines the product's appearance, function and reliability. Appropriate lubrication at the machining zone improves the tribological characteristic of Al-6061-T6 alloy, leading to higher product quality. For reasons of ambiguity during machining, the soft computing technique is chosen to predict the output. In this particular research scope, …


Cutting Force-Based Adaptive Neuro-Fuzzy Approach For Accurate Surface Roughness Prediction In End Milling Operation For Intelligent Machining Feb 2015

Cutting Force-Based Adaptive Neuro-Fuzzy Approach For Accurate Surface Roughness Prediction In End Milling Operation For Intelligent Machining

Faculty of Engineering University of Malaya

End milling is one of the most common metal removal operations encountered in industrial processes. Product quality is a critical issue as it plays a vital role in how products perform and is also a factor with great influence on manufacturing cost. Surface roughness usually serves as an indicator of product quality. During cutting, surface roughness measurement is impossible as the cutting tool is engaged with the workpiece, chip and cutting fluid. However, cutting force measurement is easier and could be used as an indirect parameter to predict surface roughness. In this research work, a correlation analysis was initially performed …


Guided Routing On Spinning Microfluidic Platforms Jan 2015

Guided Routing On Spinning Microfluidic Platforms

Faculty of Engineering University of Malaya

Flow directionality, valving and liquid routing in centrifugal microfluidics (Lab-on-CD) are typically controlled by applying centrifugal and Coriolis forces and have been the subject of active research interest in recent years. Determining and switching the flow direction at a T-junction is a common fluidic operation important for implementing several chemical and clinical assays for Lab-on-CDs. The present work describes a novel approach to route samples and control flow direction on a spinning disc that employs a guiding microstructure that relies on a two-stage valve comprised of an auxiliary inlet, which is a recess embedded at a T-junction, and a bent …


Investigating The Surface Tribology Of Roller-Burnished Polymer Using The Fuzzy Rule-Based Approach Jan 2015

Investigating The Surface Tribology Of Roller-Burnished Polymer Using The Fuzzy Rule-Based Approach

Faculty of Engineering University of Malaya

Burnishing is specified as the plastic deformation cold working process applied as surface treatment and smoothing following machining to obtain a superior surface roughness finish. The present experimental study was carried out on roller-burnished polyurethane using a roller burnishing tool. An analysis was done to investigate the effect of burnishing depth, speed, feed rate, and roller width on the surface roughness of the polymer workpiece. Roughness (R-a) prediction was achieved with a fuzzy rule-based system. The results indicate 95% accuracy between the fuzzy predicted roughness values and experimental results. Link to Full-Text Articles : www.tandfonline.com/doi/abs/10.1080/10402004.2014.962205


Modified Robust External Force Control With Disturbance Rejection With Application To Piezoelectric Actuators Jan 2015

Modified Robust External Force Control With Disturbance Rejection With Application To Piezoelectric Actuators

Faculty of Engineering University of Malaya

In micromanipulation applications, controlling the force exerted on the object is of great importance. In such cases, any uncontrolled forces may damage the object or cause system failure. However, the presence of disturbances such as impedance uncertainties and hysteresis can strongly degrade force control performance and even lead to instability. Therefore, accurate force control when internal and external disturbances occur is a significant challenge. Conventional control methods usually have a number of restrictive conditions especially on the disturbance bounds. To rectify those issues, a modified robust disturbance rejection-based force control approach is proposed in this paper. For this purpose, an …