Applied Mechanics and Materials Vol. 679

Abstract: The effects of carbon black (CB) loading on the tensile properties, electrical conductivity and swelling behavior of PVC/PEO conductive film were studied. Thin conductive film incorporation of inorganic filler, carbon black and PVC-PEO polymer blend were prepared by solution casting method. The results show that tensile strength and modulus of elasticity increase with increasing carbon black loading until 25 wt%. The percentage of mass swell test were increase with increasing carbon black loading. The result also shows that electrical conductivity of the PVC/PEO conductive film increase linearly with the carbon black loading.

Abstract: The effect of salicylic acid/ethanol as a coupling agent on the tensile properties and thermal stability of recycled high density polyethylene/wood fiber (rHDPE/WF) composites were studied. Both composites rHDPE/WF and rHDPE/WF_M (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/WF_M composites with salicylic acid exhibit higher tensile strength and modulus of elasticity and lower elongation at break than rHDPE/WF composites. It was also found that the addition of salicylic acid/ethanol shows better thermal stability in rHDPE/WF_M composites than rHDPE/WF composites.

Abstract: A method to detect fertilizer concentration of grape tree using chitosan film sensors (CFS) with 1.75% w/v has been developed. Electrochemical deposition has been chosen as an efficient technique for the fabrication of CFS. CFS has been used to detect different concentration of fertilizer ranging from 0 ppm until 60 ppm. The types of fertilizers used in this testing were magnesium sulphate and ammonium molybdate. The electrical laboratory testing result of the CFS shows the de-ionised water (DIW) has the highest response with the value ~81%. The highest response values of CFS of magnesium sulphate and ammonium molybdate content of 10 ppm concentration were ~52% and ~35% respectively. The lowest response values of CFS of magnesium sulphate and ammonium molybdate content of 60 ppm concentration were ~13.5% and ~16% respectively. The results have been proven that CFS can differentiate concentration of fertilizers. The morphological surfaces of CFS were observed with SEM and FTIR. SEM image of CFS showed the film surface was compact and the chitosan was well distributed. FTIR result shows there were N-H and OH groups in chitosan film where they were the main components to sense the fertilizer concentrations. The CFS can fulfil all the reliable sensing properties which include excellent sensitivity, recovery, response time, stability, repeatability and selectivity.

Abstract: This paper discusses the effect of grinding time on the production of submicron dolomite by using the impact and abrasion technique of high energy planetary ball mill. It is known that grinding process leads to surface activation other than exhibiting particle size reduction. Most of the energy applied during the process will be dissipated as heat that could lead to harmful effects to the structural pattern of the ground material. Thus in order to study the detrimental effects of grinding towards submicron dolomite, sample was ground at 400 rpm speed with various grinding time; 0.5h, 1h, 2h, 5h, 10h and 20h. It was confirmed using X-Ray Diffraction (XRD) method that the crystalline structure of dolomite did not deform even after 20h of grinding time, thus maintained its crystallinity. The morphological structures of ungrind and ground raw dolomite were shown by Scanning Electron Microscope (SEM) morphology.

Abstract: This study investigate about the tensile and morphological properties of degradable polymer produce from low density polyethylene/ thermoplastic soya spent powder filled spear grass loading varied from 0-3 wt %. Meanwhile, ratio of LDPE/ TSSP which is 95:5 was used as matrix in this composite. The tensile strength increased up to addition of 1.5 wt% spear grass and decreased when 3 wt% spear grass was added. SEM micrograph showed fibrils formation for sample with 1.5 wt% spear grass as it has the highest elongation at break compared to 1 wt% and 3 wt % spear grass.

Abstract: Low density polyethylene (LDPE) and natural rubber (NR) filled silica composites were prepared by using internal mixer (Brabender) at 150°C and 50 rpm for 10 minutes. Silica was incorporated into polymer matrix by three mixing routes by using Brabender. In mixing I, filler was added into LDPE/NR blend. In mixing II, filler was added prior to LDPE, which was further compounded with NR. In mixing III, filled was pre-dispersed into NR using two-roll mill, after that the compound is blended with LDPE. The effects of filler incorporation routes on the morphological and tensile properties of prepared composites were studied. Observation from SEM result showed that silica tended to localize in NR phase than LDPE phase in the composite. In addition, silica filled LDPE/NR composite exhibited the highest tensile strength in mixing II and lowest in mixing III. Tensile fracture surface of the composites showed typical morphology of LDPE and NR phase depending on mixing methods. KEYWORDS: LDPE/NR, silica, mixing order, tensile properties, morphology

Abstract: Photo-polymerized polyethylene glycol dimethacrylate (PEGDMA) scaffolds were synthesized using two macromolecular monomers of 750 and 550 number average molecular weight. Variation in chain length of macromolecular monomers visibly influenced viscoelastic properties of the compositions, exhibiting an increase in shear storage and loss modulus in PEGDMA 750 hydrogels. Furthermore, water content in the pre-polymerization mixture was a main factor determining physical appearance of the samples, where increase in water content resulted in polymerization induced phase separation, demonstrated by opaqueness of preparations containing 60 and 75% (w/w) of H₂O. In addition to this, swelling, gel fraction, compression and rheological measurements are found to be influenced by the amount of water incorporated in the hydrogels, resulting in the increased distance between polymer chains within the network. Furthermore this resulted in an apparent decrease in viscoelastic and mechanical properties of compositions, as well as in lowering their crosslinking density and compressive strength. Preliminary cytotoxicity results show no toxicity of the samples with approximately 80% cell viability after 24 h exposure of MC3T3-E1 Subclone 4 cells to the hydrogels, thus indicating that these materials could be potentially applied in the biomedical arena.

Abstract: There are numerous numbers of methods that have been introduced to the Unmanned Ground Vehicle (UGV) to find its optimal path. The purpose of this paper is to navigate a cost effective UGV known as MG-TruckS with optimal path planning in an outdoor environment. A Modified Virtual Semi Circle approach is proposed based on situated-activity paradigm. This approach is divided into two phase to compute a free collision path planning; detection and avoidance phase. Implementation of five ultrasonic range finder sensors with a very small blind zone created on purpose and the formation of three layers of influence zone shows the optimized path planning without making any unnecessary obstacle avoidance being computed.

Abstract: WSN technology has now become ubiquitous due to its flexibility, efficiency and affordability. For example the nodes in a WSN can be easily deployed in any targeted area and last for many years. The nodes can supply reliable data from within the environment with minimal disturbance to the target area.However challenges remain in providing real-time communication in some communication hostile conditions. It may not always be possible to leave the sensors in situ but instead data collection is through the use of mobile a WSN. For example as a vehicle fitted with sensing devices passes through an area of interest data is collected and relayed at certain gateway nodes back to a backhaul network for processing.In this paper our aim is to analyse the interference caused by a mobile jammer node to the stationary transmitter and receiver nodes in a network by using the OPNET Modeler software. This is early stage work aimed at developing a mobile WSN node in our future research.

Abstract: The effect of dynamic vulcanization and fiber loading on properties of low density polyethylene (LDPE)/natural rubber (NR)/water hyacinth fibers (WHF) were investigated. In this study, the vulcanized thermoplastics were obtained by in situ dynamic curing of LDPE/NR/WHF composites. The LDPE/NR/WHF composites with different fiber loading were prepared by using Brabender mixer at 180 °C with the rotor speed of 50 rpm. The results showed that dynamic vulcanized LDPE/NR/WHF composites gave a higher tensile strength, Young’s modulus, elongation at break but lower molar sorption than unvulcanized LDPE/NR/WHF composites. The SEM micrographs also displayed better fibers dispersion and the crosslink formation in dynamic vulcanized LDPE/NR/WHF composites indicated better interfacial bonding among fibers and matrix compared to unvulcanized LDPE/NR/WHF composites.