Natural fiber for green technology in automotive industry: a brief review

Fiber reinforced polymeric composites have been known and widely used because of their high specific strength and modulus compared to metals. In the last few years, biomaterials listed as a demand technology to be exploring by researchers especially in industrial purpose. This is push by environmental awareness and the over use of petrol resources lead to the development of new materials, called biocomposites, which will maintain a better future. This paper will be discussing about a brief review of natural fibers, use in automotive industry to achieve a green technology target in manufacturing of cars specifically. It's a fact that, related to weight reduction, the automotive industry can take advantages of using these materials, not only because of extinction of oil reserve, but because of high ability and importance of these materials itself in automobiles. Currently, most composites in the market are focused with long-term durability design while using nondegradable polymeric resins such as epoxies and high-strength fiber such as glass. All these materials prove to be a good characteristic of composite but still lack in environmental concern. This polymer and fiber are derived from petroleum, a nonreplenishable commodity. The momentum is to use biocomposites in common plastics to improve performance. Since the main purpose of this paper is to show a bio-composite which is suitable to replace the existing interior of automotive design, the work has focused on obtaining that bio-composite, taking account into the raw-materials cost reduction and the maintenance of the manufacturing process based on current scenario. The automotive industry is in their way to expand green technology in composites because the need is greatest. But producing the composites is energy intensive and polluting, while the durability of conventional composites, often seen as an advantage, is also their biggest challenge. Current fibers use in industry right now is difficult to dispose. They do not degrade naturally and could linger for generations

Antimicrobial activity of fingerroot [Boesenbergia rotunda (L.) Mansf. A.] extract against streptococcus mutans and streptococcus sobrinus

The extract of medicinal plants fingerroot [Boesenbergia rotunda (L.) Mansf. A.] obtained using 100% methanol was tested for antibacterial activity against two major pathogen of dental carries namely Streptococcus mutans KCCM 3309 and Streptococcus sobrinus KCCM 3207. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time-kill curve on S. mutans and S. sobrinus were analyzed using Clinical and Laboratory Standard Institutes (CLSI) methods. Preliminary antimicrobial screening showed the mean zones of inhibition for S. mutans (9.0 mm) and S. sobrinus (8.0 mm). MIC value obtained for S. sobrinus and S. mutans was 313 μg/ml while the MBC values were 313 μg/ml (S.mutans) and 625 μg/ml (S. sobrinus). Time-kill curve were obtained at concentrations of 0xMIC, 1/2xMIC, 1xMIC, 2xMIC, 4xMIC and 8xMIC. S. mutans was found to be more susceptible to the fingerroot extract than S. sobrinus. Time - kill curve showed that the concentration of 8xMIC was able to kill 99.9% of S. mutans after 4 hours treatment. These results may be useful for developing fingerroot B. rotunda as natural anticariogenic agent in toothpaste or any oral care products such as mouthwash in treatment of dental carries, sore throat and flaming gums

POSTURAL DIFFERENCES IN TURNING KICK VS BACK THRUST KICK AMONG TAEKWON-DO PLAYERS: DOMINENT LEG

There are many techniques in Taekwondo involving foots and hands. Through observations, athletes prefer to use techniques, which are easy to score and give more advantages of winning the game. In order to perform the quick movement, the body must rapidly adjust to the differences in posture to maintain a state of balance. Limited researches have been done on dynamic postural in Taekwondo. The purpose of this study is to determine the differences between the postural response to a turning kick (Dollyo Chagi) and back thrust kick (Dwit Chagi). To achieve the goal stated, 3D biomechanical analysis is done using kinematics approach. The parameters to be obtained are linear displacement of body centre of mass, kicking time duration and velocity of foot

Solvent dependence of the rheological properties in hydrogel magnetorheological plastomer

Chemically crosslinked hydrogel magnetorheological (MR) plastomer (MRP) embedded with carbonyl iron particles (CIPs) exhibits excellent magnetic performance (MR effect) in the presence of external stimuli especially magnetic field. However, oxidation and desiccation in hydrogel MRP due to a large amount of water content as a dispersing phase would limit its usage for long‐term applications, especially in industrial engineering. In this study, different solvents such as dimethyl sulfoxide (DMSO) are also used to prepare polyvinyl alcohol (PVA) hydrogel MRP. Thus, to understand the dynamic viscoelastic properties of hydrogel MRP, three different samples with different solvents: water, DMSO, and their binary mixtures (DMSO/water) were prepared and systematically carried out using the oscillatory shear. The outcomes demonstrate that the PVA hydrogel MRP prepared from precursor gel with water shows the highest MR effect of 15,544% among the PVA hydrogel MRPs. However, the samples exhibit less stability and tend to oxidise after a month. Meanwhile, the samples with binary mixtures (DMSO/water) show an acceptable MR effect of 11,024% with good stability and no CIPs oxidation. Otherwise, the sample with DMSO has the lowest MR effect of 7049% and less stable compared to the binary solvent samples. This confirms that the utilisation of DMSO as a new solvent affects the rheological properties and stability of the samples