Papers by Keyword: Fabrication

Abstract: Laminated structures are assembled so that the fibre orientation provides most of desired mechanical properties and the matrix largely determines the environmental performance. Composites laminate structures are used in a wide range of applications in aerospace, marine, automotive, surface transport and sports equipment markets. Damage to composite components is not always visible to the naked eye and the extent of damage is best determined for structural components by suitable Non Destructive Test (NDT) methods. Alternatively the damaged areas can be located by simply tapping the composite surface and listening to the sound. The damaged areas give a dull response to the tapping, and the boundary between the good and damaged composite can easily be mapped to identify the area for repair. Awareness of and inspection for composite damage should be included in the regular maintenance schedules for composite structures. Particular attention would be made to areas which are more prone to damage. The repair can be done by using composite itself or bio-composite. Bio-composite is a reinforcement of natural fibre such as plant and a material that formed by matrix or resin. Then repairs to aircraft structures are controlled and should be carried out according to the Aircraft Structural Repair Manual (SRM). For other applications the repaired components would normally be expected to meet the original specifications and mechanical performance requirements. This paper presents the fabrication technique including patch repair by using bio-composite which is kenaf and its aim to give a general approach to composite fabrication on patch repair in all applications. Through the described approach, the life of the structure is expanded and met the properties requirements such as low cost, fairly good mechanical properties, high specific strength, non-abrasive, eco-friendly and bio-degradability characteristics.

Abstract: The two different fabrications of the Micro-Electro-Mechanical Systems (MEMS) mirrors were compared: a single-crystal-silicon (SCS)-based micromachining and a silicon-on-insulator (SOI)- based micromachining. While the SOI parts had significantly smaller curved device appearance, they were outperformed in most areas by the SCS parts. This was due primarily to the smaller stress factor in the device layer in the SOI parts compared to the polysilicon layer used in the SCS parts.

Abstract: Electrospinning has emerged as a very attractive approach to the fabrication of nanofibers. In electrospinning process, the ability to control the alignment and arrangement of fibers is critical to achieve the designed functions. In this paper, we had successfully fabricated highly aligned PAN nanofibers by the method of parallel electrode electrospinning. The study revealed the optimum weight ratio of PAN polymer solution for aligned nanofibers was 8%-12%. Results show that the increasing of weight ratio of polymer solution can enhance the parallelism and uniformity of electrospun fiber diameter distribution.

Abstract: In this paper, nanocrystalline VO₂ thin film is fabricated by a kind method of two steps and its phase transition characteristics are investigated. The two-step method contains low-temperature reactive ion sputtering and post-annealing, and its process parameters determine the phase transition properties of fabricated VO₂ thin film. With optimized process parameters, VO₂ thin film with nanocrystalline structure can be successfully fabricated and has excellent phase transition performance for smart glass and optical switch.

Abstract: Hexagonal Ni micro/nanoplates were successfully prepared via a facile hydrothermal route using the polyvinylpyrrolidone as structure-directing agent. It has been verified from x-ray powder diffraction and transmission electronic microscopy that as-prepared products with high purity and fine dispersity belong to face-centered cubic microstructure of nickel metal. The magnetic hysteresis loop of the hexagonal Ni micro/nanoplates exhibits the ferromagnetic characteristics, and its coercivity increases by 25 % in comparison with the bulk nickel materials. The possible mechanism of the formation of hexagonal micro/nanoplates was suggested.

Abstract: The purpose of this research is to fabricate the hip and pelvis part for designing the acetabular implant by using Fused Deposition Modeling (FDM) technique. The methodology of this research is begin by converting the 2D image of CT into 3D image through Invesalius 3.0 software. Then the 3D image is converted to .stl format and exported to FDM machine for fabrication purpose. The finish prototype of 3D biomodel replica is evaluated in order to define the problem face by the patient. Also, the dimensional accuracy is measured between 3D replica model and 3D virtual model. Based on the result of 3D biomodel, the ball joint of the femur on the right side is dislocating from its original position because of the fracture occur on acetabular socket. The implant for acetabular fracture is design by using CATIA software and the design must ensure to be fit with the fracture area. Therefore, this study has contributed to medical area especially in Malaysia in improving patient specific preoperative planning and giving better visualization information of the fracture.

Abstract: A novel textile-based analytical device with a simultaneous, rapid, sensitive and qualitative response for analyte detection that may have a potential use in different body fluids such as sweat, blood, saliva and urine is proposed in this study as an alternative to its paper-based counterparts. A porous polypropylene spunbond nonwoven was used as base fabric which is superior to paper with higher tear and crinkle resistance, flexibility and wearability.

Abstract: Ni-Ti-Nb system alloys show wide shape memory hysteresis, suitable for assembly applications. The microstructure is composed by NiTi matrix (with some dissolved Nb) and Nb dispersed particles (with some Ni and Ti content). These particles are to cause the hysteresis widening. This work evaluates the microstructure evolution during wire fabrication process of equiatomic Ni and Ti alloys with increasing Nb content (1.5, 3.0, 6.0 and 9,0%at.). It is shown that as-cast alloys with up to 9% at.Nb and near equiatomic Ni:Ti relation show three main microconstituents: NiTi matrix phase, interdendritic eutectic phase (NiTi + β-Nb) and Ti₃(Ni,Nb)₂ compound precipitates. It was observed that NiTi matrix phase and eutectic phase (NiTi + β-Nb) have ductile behavior while Ti₃(Ni,Nb)₂ compound have fragile behavior. There was not much hardness variation during hot swaging (200-300 HV) due to recovery and recrystallization processes. Mechanical hardening prevailed as the mechanism for increase hardness of cold worked samples from 200 to 450 HV.

Abstract: Micro-machining is a fundamental process for manufacturing parts and products with dimensions of between 1 to 999 μm. Micro-Electro Discharge Machining (micro-EDM) has been used for producing of parts, molds, dies, cavities and complex three dimensional shape regardless of hardness and strength. Micro-electrodes are required for these purposes and usually micro EDM machines are used for fabricating them. Moving block electro discharge grinding (Moving BEDG) is one of the processes that can be used to fabricate micro-electrode. In this study a conventional EDM machine is used for fabricating the micro-electrode. Based on the characteristics of this machine some changes need to be applied to the moving BEDG for micro-electrode fabrication. Modification made to the moving BEDG include changing the direction of movement and control gap, use of roughing, semi finishing and finishing electrodes in one electrode. Consequently set up and machining time was decreased due to the use of roughing, semi finishing and finishing parameters. Finally, high aspect ratio micro electrode with diameter of 160.8μm was fabricated. As this process is simple and does not require high investment for special equipment; it can be used even by an ordinary workshop equipped with a conventional EDM machine.

Abstract: The short shelf-life and bulkiness of cassava roots pose a great problem in transporting these roots from the farm to the market or factory sites. To overcome this difficulty in the marketing and utilization of cassava and to avoid heavy post-harvest losses, the roots need to be processed into some form of dried product with longer shelf life. The simplest and most common mode of processing cassava is the conversion of the roots into dry chips. Cassava processing into chips by traditional methods which involve the use of knife is labour-intensive but the application of improved processing technology has reduced processing time and labour and encouraged further production. An improved cassava chipping machine, with chip thickness between 3-6mm was designed to enhance the processing of cassava into chips to catalyze its drying period and preserve its nutritional value. The chipping machine consists of a hopper, a cutter plate and a power transmission system powered by a 1 hp electric motor. Computer Aided Design software was used in the design and appropriate material selection was considered for its fabrication. The cassava chipping machine was also simulated for stress analysis and behaviour of the machine was studied when loaded virtually. Chipping efficiency is 94.75%, machine capacity is 0.04kg/sec, chipping rate is 0.034kg/sec which is a function of the force applied.