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Prosthesis is an artificial replacement for a person's missing limb to help regain mobility and the ability to manage daily activities. The type of prosthetic covered in this project is for people with below-knee amputation (BKA). Muscle fatigue is a major issue for amputees who lose a lower limb after prolonged use of artificial limbs. Available designs of prosthetics for BKA are also expensive. This study aims to design and develop an affordable and comfortable prosthetic foot with an energy-story ability for persons with BKA using an additive manufacturing process to help reduce fatigue. Three conceptual designs based were developed for this purpose. Based on the design selection matrix, the best design was chosen and developed in SolidWorks 2013 environment. Stress and strain analyses were simulated to verify the design's ability to withstand the weight of a sample patient with BKA. A sample of patient details, including weight, amputation side and sole (of the foot) length, were obtained and implemented in the prosthetic foot design. Due to its strength and durability, the design was printed on the Veglar V-821 additive manufacturing machine using Acrylonitrile Butadiene Styrene (ABS) material. A pilot test with a male patient with BKA was conducted under the supervision of a prosthetist under two conditions: standing and walking. The prosthetic prototype did not break during the test, and the patient felt comfortable using it. This finding shows that additive manufacturing can produce an affordable and comfortable prototype of a prosthetic foot using ABS. Hence, more BKA patients can benefit from inexpensive prostheses and finally help them achieve a better quality of life.

Evacuated blood collection tube (BCT) or also known as Vacutainer® is a device which accumulate negative pressure as a function of vacuum to collect blood as a specimen for pharmaceutical analysis. Nevertheless, BCT consist of three (3) components which is transparent tube, rubber stopper, and hemogard closure. Study of vacuum on BCT has become interest in many researchers about its consistency due to effect by its surrounding condition. In this research, impact of storage temperature will be studied to identify the effect of vacuum content within BCT, also to investigate the problem and seek proper (surrounding) placement for these BCT. At the same time, it should develop with a new benchmark vacuum volume (negative pressure) inside BCT aiming to obtain the standardise figure. This BCT should be placed under temperature condition between 4°C to 25°C as suggested by BD-Vacutainer® company and under certified humidity condition are ranged between 40% to 60%. It is to ensure the pharmaceutical device which is sterile and consist of shelf life does not deplete its properties drastically and sustain its life span as recommended based on technical data sheet. Thus, the amount of negative pressure in BCT presentively indicate as a shelf life.

Sewage treatment plants (STP) in Malaysia are designed to treat a load of contaminants according to the level of concentration for chemical oxygen demand (COD) and nitrogen ammonia (NH3-N) of 250 mg/L and 30 mg/L, respectively. However, studies show that the organic load of Malaysian wastewater is low and even temporarily fluctuates resulting in the low effectiveness of treatment especially in ammonia removal and consequently cause effluents that do not undergo proper treatment to be released into the environment. Therefore, this study aims to identify concentrations of COD and NH3-N in the influent of urban domestic wastewater along with other physico-chemical characteristics. Two locations of the STP were chosen based on the urban area with different catchment sizes for a population equivalent (PE) 60,000 for the first STP (LRK#1), and 150,000 for the second STP (LRK#2). These parameters include pH, temperature, conductivity, turbidity, total suspended solids (TSS), nitrogen nitrate (NO3-N), total Kjeldahl nitrogen (TKN) as well as heavy metals such as Cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb), and Zinc (Zn). The sampling and analysis methods used the guidelines recommended in the American Public Health Association (APHA). The results give the highest average COD concentrations for the LRK#1 and LRK#2 are 180.5 mg/L and 380.9 mg/L, respectively. The highest NH3-N concentrations were 33.53 mg/L for LRK#1 and 31.63 mg/L for LRK#2. Overall, the wastewater physico-chemical characteristics of both treatment plants show wastewater in the medium and low concentration categories.

Silica/carbon composites from the carbonization of rice husk have been employed to act asheterogeneous Brønsted acid catalysts. These composites have been used to catalyze theacetalization of phenylacetaldehyde, vanillin, and 2-acetonaphthone with propylene glycol toproduce hyacinth, vanilla, and orange blossom scent fragrances. As the carbonization temperaturesaffect the physicochemical properties and hence their catalytic activity, several characterizationtechniques and data manipulation have been performed to understand the correlations. Acid densityand hydrophilicity has been proved to play a crucial part to obtain an optimized yield of desiredproducts.

Renewable polymers with excellent stretchability and self-healing ability are interesting for a wide range of applications. A novel type of wholly biobased, self-healing, polyamide-based thermoplastic elastomer was synthesized using a fatty dimer acid and a fatty dimer amine, both containing multiple alkyl chains, through facile one-pot condensation polymerization under different polymerization times. The resulting elastomer shows superior stretchability (up to 2286%), high toughness, and excellent shape recovery after being stretched to different strains. This elastomer also displays high room-temperature autonomous self-healing efficiency after fracture and zero water uptake during water immersion. The highly entangled main chain, the multiple dangling chains, the abundant reversible physical bonds, the intermolecular diffusion, and the low ratio of amide to methylene group within the elastomer are responsible for these extraordinary properties. The polymerization time influences the properties of the elastomer. The use of the optimal self-healing thermoplastic elastomer in anticorrosion coating, piezoresistive sensing, and highly stretchable fibers is also demonstrated. The elastomer coating prevents stainless-steel products from corrosion in a salty environment due to its superhydrophobicity. The elastomer serves as a robust flexible substrate for creating self-healing piezoresistive sensors with excellent repeatability and self-healing efficiency. The elastomer fiber yarn can be stretched to 950% of its original length confirming its outstanding stretchability.

Suspensions containing 8 and 10 wt% polyacrylonitrile (PAN) and 1, 2, 3, 5, 7 and 10 wt% graphene oxide (GO) were prepared using a special mixing routine and fibres were generated from these mixtures by pressurised gyration. The combination of pressure and gyration speed was effective in controlling the fibre morphology and fibre diameter which ranged from 1 to 20 μm. Fibres were pyrolysed to remove the polymer and only the 10 wt% PAN fibres survived. The microstructure of the pre- and post-pyrolysis products were characterised by scanning electron microscopy, both with and without focussed ion beam etching, Fourier-transformed infrared and Raman spectroscopies. Pyrolysed fibre electrical conductivities were measured and only those containing 1 and 2 wt% GO were conductive.

A simple and effective process combining pressure and gyration has been developed and used to jet-out composite fibres containing graphene nanoplatelets. Thermoplastic polyurethane and phenolic resin polymers were used as matrices. Processing parameters such as rotation speed, pressure and polymer concentration had a marked influence on the composite fibre diameter. Focussed ion beam milling and etching verified the effective incorporation of the graphene nanoplatelets into the composite fibres. Morphological, rheological, physico-chemical and thermal properties of the composite fibres were evaluated to identify possible applications for them.

Hydroxyapatite (HAp) is one of the most versatile materials used for implantation purpose due to its similarity to natural bone material with a composition around 70% of our bone. Not only that, it is regarded as attractive biomedical materials because of their outstanding bioactivities and non toxicity. The purposes of this particular project are mainly to produce HAp powder by utilizing eggshell waste as its main raw material as well as to study the effectiveness of eggshell substitution in HAp on mechanical behaviour. The process involves drying and thermal decomposition of eggshell followed by hydrothermal reaction at low temperature with di-ammonium hydrogen phosphate and water. After that, the next process that takes place will involve compacting of the powder at pressure of 80 kg/cm2and sintering at temperature of 900-1300oC. Therefore, by using the suitable synthesizing method together with the workable sintering schedule for each synthesizing process, the optimized microstructure and properties of sintered HAp can be prepared.

Flux Core Arc Welding (FCAW) is an arc welding process that using continuous flux-cored filler wire. The flux is used as a welding protection from the atmosphere environment. This project is study about the effect of FCAW process on different parameters by using robotic welding with the variables in welding current, speed and arc voltage. The effects are on welding penetration, microstructural and hardness measurement. Mild steel with 6 mm thickness is used in this study as a base metal. For all experiments, the welding currents were chosen are 90A, 150A and 210A and the arc voltage is 22 V, 26 V and 30 V respectively. 20, 40 and 60 cm/min were chosen for the welding speed. The effect will studied and measured on the penetration, microstructure and hardness for all specimens after FCAW process. From the study, the result shown increasing welding current will influenced the value depth of penetration increased. Other than that, the factors that can influence the value of depth of penetration are arc voltage and welding speed.

Gas Metal Arc Welding (GMAW) process is leading in the development in arc welding process which is higher productivity and good in quality. In this study, the effects of different parameters on welding penetration, microstructural and hardness measurement in mild steel that having the 6 mm thickness of base metal by using the robotic gas metal arc welding are investigated. The variables that choose in this study are arc voltage, welding current and welding speed. The arc voltage and welding current were chosen as 22, 26 and 30 V and 90, 150 and 210 A respectively. The welding speed was chosen as 20, 40 and 60 cm/min. The penetration, microstructure and hardness were measured for each specimen after the welding process and the effect of it was studied. As a result, it obvious that increasing the parameters value of welding current increased the value of depth of penetration. Other than that, arc voltage and welding speed is another factor that influenced the value of depth of penetration. The microstructure shown the different grain boundaries of each parameters that affected of the welding parameters.

The usage of recycled rubber in tire production is not common. This paper mainly focuses on feasibility of recycled tire to be used in production, particularly on thermal and rheological behavior of the blended recycled rubber and natural rubber. The investigation has been conducted on the blend of recycled rubber (RR) and natural rubber to determine the suitable composition of RR and SMR (Standard Malaysian Rubber) for the manufacturing of tire thread. RR which was taken from the thread of lorry tires was blended with two natural rubber types; SMR-L and SMR-10 at different mass ratio. The thermal characteristic was studied using Differential Scanning Calorimetry (DSC) while Capillary rheometer and Mooney viscometer was used to study the rheology behavior of the blends. It was found that SMR-10 has increased the thermal stability of the blend as opposed to SMR-L. Both natural rubber blends show similar relationship between shear viscosity and shear rates but SMR-10/RR blends exhibit higher viscosity than SMR-L/RR blends based on Mooney viscosity analysis.

Stearic acid (SA) was used as an additive in the process of metal injection moulding (MIM). It was added to the wax/polymer mixture in order to modify the powder wetting, mould lubrication, mixture viscosity, residual stress and debinding behaviour. In this study, the effect of SA in feedstock formulation on mixing torque and rheological properties was investigated. Further, it’s correlation on the as-moulded and as-debound parts behaviour was also investigated. The results showed that addition of SA significantly reduced the mixing torque value and viscosity which correspond to decreasing in inter-particle friction. As a result, injection moulding could be carried out at a lower temperature to achieve sound moulded parts and increased the removal rate of binder during solvent extraction process. However, it seemed that increasing the SA had a little negative effect on the as-moulded density.