Dirk Rilling

Tribological Characteristics of Sustainable Fiber-Reinforced Thermoplastic Composites under Wet Adhesive Wear

The friction and specific wear rate of sustainable kenaf fiber–reinforced polyurethane composites were investigated against stainless steel counterface and under wet contact conditions. The new composites were evaluated at different applied loads (50–80 N), sliding distances (up to 2.7 km), and fiber mat orientations. Scanning electron microscopy (SEM) was used to observe the damage features on the worn surfaces. The results revealed that sustainable kenaf fibers assisted in enhancing the wear and frictional performance of the polyurethane thermoplastic composite by about 59 and 90%, respectively. Operating parameters and mat orientation controlled the wear and the frictional behavior of the composite. Better wear performance was exhibited at high loads and when the fiber mats were oriented perpendicularly to the sliding direction. Observations of the worn surfaces revealed different features of damage such as microcracks, fiber tearing, fiber detachment, and delamination. However, there was no trace of fiber pull-out in any of the tested conditions.

A Novel Hybrid ACO/SA Approach to Solve Stochastic Dynamic Facility Layout Problem (SDFLP)

This paper proposes a new hybrid algorithm using ant colony optimization and simulated annealing intelligent approaches to solve a stochastic dynamic facility layout problem in which product demands are normally distributed random variables with known probability density function that changes from period to period in a random manner. Finally, the performance of the proposed algorithm is compared with the simulated annealing and another approach using data taken from the literature.

Investigations on wear and frictional properties of kenaf fibre polyurethane composites under dry and wet contact conditions

In this paper, an investigation was conducted to understand the wear and frictional properties of kenaf fibre reinforced polyurethane composites. The effect of applied loads (30 to 80 N), sliding distance (up to 2.7 km), and fibre orientation [i.e., parallel (P–O), anti–parallel (AP–O) and normal (N–O)] were determined under dry and wet contact sliding. Specific wear rates for all fibre orientations improved under wet contact except parallel orientated composites. Presence of water in wet sliding has significantly reduced the friction coefficient compared to dry sliding besides acting as a cooling agent. A scanning electron microscope (SEM) was used to study the worn surfaces and wear mechanism encountered. The predominant wear mechanism observed under dry sliding was micro–cracks, plastic deformation and thermo–mechanical deformation. Meanwhile, the worn surfaces under wet contact are very minimal, namely micro–ploughing at elevated sliding distances.

On Integration of Mirror Collector and Stirling Engine for Solar Power System

In the current work, several types of solar collectors, i.e. parabolic, cylindrical, and mirrors, were designed and fabricated. The aim of this study is to integrate the optimum collector with Stirling engine in Malacca city, Malaysia. Stirling engine was designed using CATIA software. The solar collectors were tested for several sunny days and the temperature in the focus point was measured. Comparing the experiment results shows that mirror solar collector introduces highest temperature among others, which was about 190°C. According to that temperature, the Stirling engine has been designed in bore piston dimension of 50 mm. Alpha Stirling engine type was selected for this purpose, which may run in this range of temperature.

Kenaf fibers for tribo-thermoplastic composites

In the present work, wear and frictional characteristics of thermoplastic epoxy resin reinforced with treated kenaf fiber (T-KFRE) is investigated. The T-KFRE composite was tested against smooth stainless steel using a block on disc (BOD) apparatus at 2.8m/s sliding velocity and variable applied loads (10-60N) and sliding distance (0- 2.7km). The T-KFRE was investigated under Parallel (PO) in relation to sliding direction. Adhesive wear results revealed that T-KFRE has a superior and high degree of wear resistance when slid against a stainless steel counter face in comparison to neat epoxy. The friction coefficient varied between the ranges of 0.35 and 0.65 in relative to sliding distance of up to 2.7 km. SEM study showed different wear mechanism such as pitting, delamination, breakage and micro cracks especially for lighter applied loads. Meanwhile, heavier loads showed less damage to the surface, which in turn exhibited, better wear performance and frictional characteristics.