Micro Aerial Vehicles, otherwise known as MAVs, is defined as an aerial vehicle that has a 15cm or less wingspan with a take off wight of less than 200g. Its miniature size and manoeuvrability allows it to fly in confined space at low Reynolds number flight conditions (100 – 100,000). In this study, an entothopter design inspired by dragonfly wings was investigated using a subsonic wind tunnel to see the effect of tandem wing configuration on the lift generation. The study was done at different flapping frequency (5-11Hz) and at different flight speed (5m/s, 7m/s, and 9m/s). It was observed that in phase flapping configuration produces better lift for all flapping frequency and all flight speed.
The tubercle effect is a recently discovered phenomenon where the sinusoidal pattem ‘bumps’ on the leading edge of an airfoil can improve the aerodynamic performance. This effect was inspired by looking at the humpback whale pectoral flippers that give an exceptional acrobatic manoeuvrability in the water such as somersaults, also allowing for easier capture of prey. The objective of this research is to study the effect of implementing the tubercles concept on the car spoiler in order to see whether it bring advantage or disadvantage in the aerodynamic performance of a car. The design and simulation process are done by using Solidworks. The design of airfoil spoiler based on Selig S2091 (low Reynolds number airfoil) with sinusoidal pattern leading edge were computationally used. The Airfoil spoiler with 270 mm of the chord length (C), 1200 mm wingspan (L) and angles of attack of -5°, 0°, 5°, 10°, 15°, 20°, 25°, 30° were improvised with tubercles at 40 mm amplitude of bumps (h) and the distance of the wavelength between peaks (λ) of 1200 mm, 240 mm and 133.33 mm. The simulation was tested at 40 m/s. The investigation shown that the tubercles can improve the aerodynamic performance of car rear spoiler where the tubercles are able to increase the lift coefficient but has a significant decrease in drag only at 20° and above angle of attack.
In Malaysia perspective, the application of nanotechnology is crucial towards achieving the country’s objective as a developed nation by 2020. This paper aims to examine the current Malaysia laws and statutory regulations of nanotechnology applications, to investigate the occupational diseases and work-related accidents associate to nanotechnology and to examine the risk assessment and management practices executed by the nanotechnology-based manufacturers to facilitate the potential effects of nanomaterials. Nanotechnology is a technology that incorporates nanomaterials, which is extremely small materials in size, equivalent to 1/80,000th of the width of a human hair. Due to their distinctive size, these nanomaterials may contribute to the significant health risks and hazards. The findings conclude that there is no specific law and statutory regulation on nanotechnology application exists in Malaysia. Thus, the none existence of nanotechnology laws means there is no protection of persons at work. Malaysia is currently formulating safety standards relevant to nanotechnology. Recently, the Department of Occupational Safety and Health (DOSH) has published the Guideline on Control and Safe Handling Nano Materials by the end of 2018. It provides information and recommendations on handling nanomaterials in the workplace. According to the DOSH personnel that there is no record of occupational disease and work-related accidents related to nanotechnology per se. In relation to the risk assessment and management activities, most of the respondents from the nanotechnology-based manufacturer indicated that there is no nanotechnology risk assessment and management practices being executed in their workplace. Most of them also concluded that they have no knowledge about the latest guideline published by the DOSH on control and safe handling of nanomaterials in the workplace.
One of the crucial stages in fabrication of WC-Co composite is sintering process. Inappropriate sintering state, especially sintering temperature will lead to an abnormal grain growth and thus reduce the mechanical properties of the sintered parts. Sintering atmosphere also plays a big role in oxidation, carburizing, decarburizing and nitriding on the surface of sintered parts. Prevention of any unwanted process during sintering is demanded to maintain the performance of WC-CO composites without any by-products. In this work, the effect of different sintering atmosphere and sintering temperatures was studied on the mechanical properties of WC-Co composites. 95% nitrogen (N2) mixed with 5% hydrogen (H2) gases was used as sintering atmosphere in a tube furnace whereas vacuum atmosphere was carried out in vacuum furnace. The sintering process was conducted at 1300ºC and 1400ºC, respectively. Higher relative density, hardness and transverse rupture strength (TRS) were observed on the sintered parts. Sintering under N2-H2 atmosphere exhibited better mechanical properties. Low mechanical properties observed in vacuum atmosphere was probably due to over-sintering which led to grain growth activities and formation of ηphase.
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