Abstract: This paper discloses a method to recycle polystyrene (PS) waste by adding ethanol based hydrocarbons solvent to produce a novel adhesive for wood joining application. In the experiments, tensile shear strength of wood lap joint having various overlap lengths was conducted. It was found that this new adhesive has significant shear strength as compared to commercial wood adhesive. This relatively low cost adhesive has potential to be used for wood joining application especially in marine structures.
Abstract: Application of cutting fluid that provides both coolant and lubrication properties in manufacturing operations such as turning, milling, grinding and other processes has been proven to improve the machining output in many aspects. In cryogenic machining, liquid nitrogen (LN2) is used as cutting fluid to reduce the temperature generated at the cutting zone. However, there is still an issue being raised on whether LN2 also functions as a good lubricant as it does as an excellent coolant. Therefore, an intensive study on the chip formation during dry and cryogenic turning of AISI 4340 alloy steel has been conducted to examine the effect of LN2 cutting fluid on the reduction of friction between the chip and the tool. Results from calculation of coefficient of friction indicate that application of LN2 during turning is able to help the friction reduction up to 73%. Smaller value of coefficient of friction indicates that the shear angle is larger which results in smaller shear plane area that provides benefits of lower cutting force needed to shear off the chips and lower cutting temperature being generated during the machining process.
Abstract: In the area of tribology, surface roughness has become one of the most important factors that contributed to the evaluation of part quality during machining operation. In order to understand the behavior of cryogenic cooling assistance in machining Inconel 718, this paper aims to provide better understanding of tribological characterization of liquid nitrogen near the cutting zone of this material in milling process. Experiments were performed using physical vapor deposition (PVD) - coated carbide inserts under cryogenic and dry cutting condition. The cryogenic results of the cutting temperature, cutting forces and surface roughness of the ball nose cutting tool have been compared with those of dry machining. Finally, experimental results proved that cryogenic implementation can decrease the amount of heat transferred to the tool up to almost 70% and improve the surface roughness to a maximum of 31% when compared with dry machining.
Abstract: The effect of salicylic acid as a coupling agent on the tensile properties, and morphology analysis of recycled high density polyethylene/wood fiber (rHDPE/WF) composites were studied. Both composites rHDPE/WF and rHDPE/WFM (treatment with salicylic acid) were prepared using Brabender Plasticorder at temperature of 160°C and rotor speed of 50 rpm. The result indicated that rHDPE/WFM composites with salicylic acid exhibit higher tensile strength and modulus of elasticity but lower elongation at break than rHDPE/WF composites. The SEM micrographs showed that the wood fiber was more widely dispersed in the rHDPE matrix with addition of ethyl salicylate than rHDPE/WFM.
Abstract: There is significantly abundant portion of waste agricultural materials in the world serving as environmental challenge, however, they could be converted into useful value added products like activated carbon. Coconut shell based carbons were synthesized using physical activation by CO2 and chemical activation with potassium hydroxide and potassium acetate. The BET surface areas and pore volumes are 361m2/g and 0.19cm3/g for physical activation, 1353m2/g and 0.61cm3/g for activation with KOH and 622m2/g and 0.31cm3/g for potassium acetate activated carbon. From the Fourier Transform Infrared Spectroscopy analysis, hydroxyls, alkenes and carbonyl functional groups were identified with more prominence on the chemically activated porous carbons. Thermogravimetric analysis (TGA) results showed occurrence of moisture pyrolysis at 105°C, the pyrolysis of hemicellulose and cellulose occurred at 160–390°C and lignin at (390-650°C). Carbonization at 700°C and 2hrs had highest yield of 32%. Physical activation yielded lower surface area with approximately 88% micropores. On the other hand, chemically activation yielded higher surface area with elevated mesopores. The porous carbons can be applied to salvage pollution challenges.
Abstract: This paper aims to understand the relationship between processing parameters and compressive properties of nanoclay filled polyester resin (dispersion method and wt% of nanoclay particles). Unsaturated polyester resin with 0-5 wt% nanoclay content was prepared by hand mixing and through shears mixing of water bath shaker. Static uniaxial compression tests were conducted to investigate how the unsaturated polyester resins with nanoclay contents and processing will effect on the compressive stress-strain behaviour and compression properties. The experimental results show that the compressive strength and elastic modulus of nanomodified resin are significantly affected by type of mixing methods to prepare the specimens and the ratio of nanoparticles content during mixing. It was found out that the compressive strength and compressive modulus increase with the nanoclay content. The findings also indicate the dispersion of nanoclay by hand-mixed method yield higher compressive strength compared to that dispersed by water shaker bath.
Abstract: The designs of thin structure components of aerospace vehicles require the consideration of thermal buckling and post-buckling problems. Thermal buckling of the structures in the aerospace environment may occur due to non-uniformly distributed temperature field. A finite element method study on the post-buckling of composite plates with embedded shape memory alloy wires was conducted. The plates were subjected to in-plane and through-thickness non-uniform thermal loadings where the non-uniform temperature distributions considered were parabolic in-plane and linearly varying through-thickness thermal loadings that may act separately or in combination. Recovery stress induced by the shape memory alloy was exploited to improve the thermal buckling behaviours of the composite plates. A non-linear finite element model along with its source codes that considered the recovery stress of the shape memory alloy, the non-uniform temperature field, the temperature dependent properties of the SMA and the composite matrix were developed. The post-buckling paths that showed the effect of the shape memory alloy on the thermal post-buckling behaviour of composite plates were generated using the source codes. It was found that the strain energy tuning method of the shape memory alloy greatly improved the post-buckling behaviour of composite plates subjected to the non-uniform temperature distributions.
Abstract: Porous concrete technology has been used since 1970s in various parts of the United State as an option to complex drainage systems and water retention areas.Porous concrete pavements have become popular as an effective stormwater management device to control the stormwater runoff in pavement. The objective of this paper is to study a pre-review on Porous concrete pavement and it previous laboratory study. From the literature, it was found that, the strength of the porous concrete pavementstill need to improve. To improve the strength of the porous concrete, various additive have been study as a part of porous concrete mix and yetthe optimum condition to produce good porous concrete still not been established. From the previous study, it was found that to prepare the porous concrete laboratory specimen, the use of standard Proctor hammer (2.5kg) and Pneumatic press (70 kPa compaction effort) resulted in the closest properties to the field porous concrete.
Abstract: In the current study, poly (hydroxy butyrate-co-hydroxy-valerate) (PHBV) was blended with a synthetic polymer poly (L-lactic acid) (PLLA), to control the degradation rate and process of composite scaffolds, as PLLA has a much higher degradation rate than PHBV. PHBV/PLLA blends were used as polymer matrices for composite scaffolds. Emulsion freezing / freeze-drying technique was used to fabricate composite scaffolds based on these blends and containing nanosized hydroxyapatite (nHA). In vitro degradation tests of composite scaffolds were conducted by immersing samples in phosphate buffered saline (PBS) for various periods of time. It was found that the composition of polymer blends affected water uptake of scaffolds. Composite scaffolds exhibited enhanced adsorption of bovine serum albumin (BSA), a model protein.