M.M.H. Megat Ahmad

Numerical and experimental investigation into porous squeeze films

The paper presents a numerical and experimental investigation into porous squeeze films with a view to application in the printing process. The experimental programme was carried out using targets having different permeability and this work confirmed the dominance of hydrodynamic behaviour associated with the thick film and porous medium flow when the film becomes thin. The numerical model has been implemented via the finite element method and the prediction shows good overall agreement with the data obtained from the experimental investigation. In performing sensitivity calculations, for the physical parameters of practical interest, it was found that the inclusion of slip velocity affects the film thickness decay, but only by a small amount. When the model was applied to the parameters of the actual printing process, it was demonstrated that the volume flowrate of the ink dot which penetrates into the paper and which spreads on it can be obtained from the model, but the penetration component is negligible. In comparing predicted and measured dot gain, initial film thickness was found to be a dominant parameter and the most likely cause of the discrepancy between measured and predicted values.

Bamboo, Thermoplastic, Thermosets, and their Composites: A Review

This paper reviews the topic of bamboo mechanical properties in thermoplastic and thermosets polymer composite. It highlights previous work done in bamboo fiber in terms of the reinforcement composite material. Mechanical testing with experimental has been studied. This literature study will be a good source for those who are interested in doing research for this topic. An overall 62 references have been cited for the further investigation.

Cervical spine injuries sustained by motorcyclists in road crashes in Malaysia

Abstract This study looks at cervical spine injuries sustained by motorcyclists in motorcycle road crashes. The motorcyclist is relatively more exposed to road hazards compared to the protected car passenger. They are therefore more prone to injury than those traveling in any other form of transportation. The motorcycle is relatively less stable and accords little protection to passengers in road crashes compared to a four-wheeled vehicle. The cause of injury and injury mechanisms are more uncertain for a motorcyclist compared to a car driver. The objective of the present study is to correlate the motorcycle crash mode to the cervical injury sustained by motorcyclists in real-world scenes. Motorcyclists with cervical injuries admitted to the hospitals were selected for investigation. The types of injuries sustained were acquired from medical reports. Information on the crash scene and crash mode was obtained from police reports and interview sessions arranged with the motorcyclists involved in the crash. Generally, a high count was noted for injuries to the lower cervical vertebrae, especially at vertebrae C5, intervertebral C5-C6, and vertebrae C6. The upper cervical spine was observed to have a high frequency of injury at C2, especially the odontoid process. Statistical analysis reveals that the vehicle crash mode is significant in determining the cervical injury mechanism sustained by motorcyclists (p < 0.05), and thus basic injury types sustained. Neck flexion and extension movements are the most frequent neck injury mechanisms, especially in frontal and rear end impacted motorcycles. Burst fractures were commonly observed in frontal impacts, while side impact and skidding motorcyclists were found to have a high frequency of uncinate process fractures, a result of neck lateral flexion. At the end of the study, a logistic regression model was developed. The model is simple and may be referred by paramedics in making any prompt prediction related to neck injury of motorcyclist due to road crash.

Development and mechanical characterization of green bamboo composites

In this study, a bamboo composite is developed using specific bamboo species known as Gigantochloa Scortechinii (Buluh Semantan) which can be found in Malaysia. In precise, the woven bamboo (WB) was formed from the culm fier composite with an average of 0.5 mm thickness and 5.0 mm width strip is laminated with Wowen E Glass (WEG) and reinforced with epoxy (EP). The laminated was using a hand lay-up technique. The developed bamboo composites are then characterized comprehensively in the term of tensile, hardness, impact, fatigue and fracture test. It is found that the strength was equivalent with the existing steel alloy in term of tensile and fracture properties.

Investigation of Hardness of Short Abaca (Musa Textile Nee) Fibre-Reinforced High Impact Polystyrene (HIPS) Composites by Response Surface Methodology

In this paper, the hardness property of abaca (Musa textile Nee) fibre reinforced high impact polystyrene (HIPS) composites with maelic anhydride (MAH) used as coupling agent and styrene butadiene styrene (SBS) copolymer rubber (Cyclo resin) used as impact modifier was investigated using response surface methodology.. The composites were initially fabricated using a rolling machine and finally using a hot press machine to obtain a desired thickness. These samples were then tested for Brinell hardness test. A statistical approach of response surface methodology was used to obtain the interaction between various compositions mentioned above for abaca fibre reinforced HIPS composites. The BHN (Brinell hardness number) was analyzed using response surface methodology (Box Behnken method).

The effects of weathering on mechanical properties of kenaf unsaturated polyester composites (KFUPC).

Exposure to natural weathering changes the mechanical properties of unsaturated polyester composites. These changes can negatively affect the mechanical properties of natural fibre composites, through UV radiation and relative humidity. The idea of this study was to determine the durability of kenaf unsaturated polyester composites (KFUPC) in natural conditions, and in addition, to determine the effects of weathering on the performance of these composites and the biodegradability possessed by the composite when exposed to natural weather. KFUPC composites were exposed to the atmosphere for four months. Humidity up-take tests were performed on composite specimens containing (10%, 20% and 30%) weight percentage of fibre content. The tensile properties of exposed specimens were evaluated, and compared alongside dry composite specimens. A decrease in tensile properties of the weather exposed composites was demonstrated, compared with the dry samples. The percentage of moisture uptake increased as the weight percentage of fibre increased, due to the high cellulose content.

Gravity Effects of Curing Angle on Laminated Composite Structures: A Review on Novel Study

Composites manufactured by small and medium industries/entrepreneurs (SMI/E) are conventionally cured in the horizontal position. Hence, the confined space restricts optimum productivity. Besides, SMI/E is unable to allocate high budget for high-end technology such as autoclave and vacuum mechanical oven which limits the development of SMI/E as a result of high capital cost. Through a series of literature review, the review confirmed that there is no similar scientific study has been conducted. Consequently, the review is carried out to facilitate the investigation of the feasibility of a gravity cured glass fiber laminated thermosetting composites via vacuum bagging at angle position from horizontal (0°) to vertical (90°) to enhance the curing space required.

Effects of layout design changes on frontal crash behaviour of small motorcycles

ABSTRACT Motorcycle frontal crashes always cause serious and fatal head injuries to riders, and the behaviour of riders was known to be influenced by the behaviour of the motorcycle during crashes. Thus the present work was carried out with the main objective to study the effects of changes of layout design of a small motorcycle, particularly in regards to the arrangement of the engine block and air filter casing, on its behaviour in frontal crashes. The study was performed via finite element simulations using a motorcycle model with fully functional and deformable front wheel and fork structures. A two-level factorial experiment approach, 23, was used for the parametric study design, with the peak magnitude of horizontal and vertical accelerations of the motorcycle in the crash as response variables. The key peak magnitude of both the acceleration components which were found to be substantially affected by the layout changes showed the differences of 26.8% and 43.9% between the designs that yield the lowest and highest accelerations, respectively, for the horizontal and vertical accelerations. Empirical models for predicting the peak magnitude of the corresponding accelerations were established and the effect plots were also produced. The crash behaviour of the motorcycle in relation to the crash safety was discussed and it was concluded that the behaviour of the motorcycle in frontal crashes could be enhanced for better crash safety by a proper design of motorcycle layout.

Tensile Properties of Angle Cured Laminated Composites Structures under Gravity Effects

As the usage of composites materials are significant in the industries of automobiles, shipping and constructions due to their non-corrosive and high strength to weight ratio. Anyway, the production of composites needed to be increased to meet the demand. At this stage, problem faced by Small and Medium Industries / Entrepreneurs (SMI/E) is the confined and limited space available that restricts the optimum productivity. They commonly cure the composites horizontally that requires ample space and unable to afford for high-end equipment such as mechanical oven and autoclave in the production as a result of high capital cost.This research is carried out to study the feasibility of the gravity effects on curing position of the laminated composite structures to enhance the curing space needed. The aim of the research was to investigate the tensile properties of the thermosetting laminated composite by curing the laminate at different angle using vacuum bagging technique. From the testing, SN 5 which denominated to be 60 ̊ found to have the best tensile properties in term of maximum force exerted and Youngs modulus.

Differential Scanning Calorimetry (DSC) Analysis of Abaca Fibre (Musa Textile Nee) Reinforced High Impact Polystyrene (HIPS) Composites

Differential scanning calorimetry (DSC) was used to study the thermal behaviour of abaca fibre reinforced high impact polystyrene (HIPS) composites. Thermal analysis is based upon the detection of changes in the heat content (enthalpy) and the glass transition temperature (Tg) of optimum condition of abaca fibre reinforced HIPS composites. In this research, glass transitions temperature (Tg) of neat HIPS occurred below the Tg of optimum condition of composites as the temperature of an amorphous state. The endothermic peak of composites was in to range 430-435°C including neat HIPS and it observed that enthalpy of abaca fibre reinforced HIPS composites yielded below the neat HIPS 748.79 J/g.