Characterization of Radiation Modified Sago-Polyvinyl Alcohol Blends Films

Blends from sago starch, poly (vinyl alcohol)(PVA) and distilled water have been prepared and subjected to electron beam irradiation with doses ranging from 10 to 40 kGy to form hydrogels. The hydrogels were then cooled in refrigerator overnight to remove trapped bubbles formed during irradiation reaction. Films were subsequently produced by drying hydrogels in an oven. The characteristic of the irradiated blends and films were then determined. Poly (vinyl alcohol) solution was found to be viscous obviously after irradiation indicated the formation of irradiation induced crosslinking. Radiation degradation of sago starch solution was confirmed by observing the viscosity of the solution which was lowered after irradiation. The gel content of irradiated films was increased compared to unirradiated. Crosslinking/grafting had occurred in the blends at optimum dose of 20 kGy. The gel content of poly (vinyl alcohol) film was maximum at 30 kGy. Above 30 kGy, over crosslinking occurred as the film was shrunk to the smaller size. Melting temperature of PVA film as determined by Differential Scanning Calorimetry decreased with increasing irradiation dose. This indicate that cross linking had lowered the melting point of PVA film. The existence of only one peak of melting temperature by Thermo Gravimetric Analysis revealed the compatibility of the blends. Scanning Electron Miscroscopy studies on the surface morphology and freeze fracture revealed more evidence of the radiation induced crosslinking and grafting of the blends. Studies also done on effect of sago and PVA contents of the blend, addition and types of plastisizers added and irradiation dose on the quality of the film produced. Results show that irradiation has improved the tensile strength but elongation at break was slightly reduced for blends S25/P75, S50/P50 and S75/P25. The biodegradability of sago, PVA and blends films was studied by monitoring its weight loss for 6 months. Sago starch film was totally degraded in the first month of burial period but PVA film remain un intact for the last six months. Incorporating sago starch to the blend sago-PVA improved the weight loss up to 60% in six months

Pollen characters of Firmiana Malayana Kostem. (Malvaceae: Sterculoideae) in Malaysia

Firmiana malayana also known as "Bullocks eye or Mata Lembu" in Malaysia and can be found along riverbanks and open forests in Peninsular Malaysia and seldom planted in populated areas. The flowers of the Firmiana malayana are vivid orange in colour, on tassels up to 12?cm long. Usually this species will shed its leaves after a dry period and remains bare for six to eight weeks. The objective of this study is to determine the pollen morphological characteristics of the Firmiana malayana in order to add more information on the species under the family of Sterculiaceae in Malaysia. Methods for this study includes acetolysis technique for the pollens and viewed under light microscope and scanning electron microscope. Results shown that the pollens of the species Firmiana malayana appeared to be monad and dyad with tricolporate class with both porate and colpus present. The shape of this species is prolate with P/E index of 1.49. This species was considered as medium-size pollens as the pollens ranges from 26-36?μm. The ornamentation of the pollen is reticulate where the ornamentation is network-like pattern formed by exine elements of lumen and murus. Based on the results obtained, pollen morphology is a great tool that can aid in plant identification and classification as well having taxonomic values

Circle grid fractal plate as a turbulent generator for premixed flame: an overview

This review paper focuses to ascertain a new approach in turbulence generation on the structure of premixed flames and external combustion using a fractal grid pattern. This review paper discusses the relationship between fractal pattern and turbulence flow. Many researchers have explored the fractal pattern as a new concept of turbulence generators, but researchers rarely study fractal turbulence generators on the structure premixed flame. The turbulent flow field characteristics have been studied tand investigated in a premixed combustion application. In terms of turbulence intensity, most researchers used fractal grid that can be tailored so that they can design the characteristic needed in premixed flame. This approach makes it extremely difficult to determine the exact turbulent burning velocity on the velocity fluctuation of the flow. The decision to carry out additional research on the effect circle grid fractal plate as a turbulent generator for premixed flame should depends on the blockage ratio and fractal pattern of the grid. 1

Gamma irradiated Py/PVA for GOx immobilization on tapered optical fiber for glucose biosensing

Tapered optical fiber coated with pyrrole/poly(vinyl alcohol)-glucose oxidase (Py/PVA-GOx) for glucose biosensing was successfully fabricated by radiation immobilization of GOx onto polymeric surfaces. Polymerization of pyrrole and PVA crosslinking was carried out by means of gamma irradiation. The nature of enzyme immobilization was studied by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and atomic force microscopy. The observation of an absorption band at 1650 cm−1 and binding energy formed at 287.5 eV confirm the occurrence of GOx immobilization on the polymer matrix. An increase in film thickness is observed after irradiation, which confirms the entrapment of GOx into the Py/PVA polymer matrix. The peak to valley roughness for the irradiated Py/PVA-GOx reveals the intermolecular interaction between the polymers and enzyme. These characteristics are linked to the enzymatic reaction of the coated optical fiber towards the glucose concentration. The kinetic property of the GOx in the irradiated Py/PVA-GOx coated fiber was studied with a very low value obtained for the Michaelis-Menten constant, which contributes to improved adhesion and immobilization on the coated fiber. The response and sensitivity of the coated optical fiber were recorded as <0.31 μW and 8.7 × 10-3 μWmM-1, respectively. A selectivity study reveals that the irradiated fiber coated with Py/PVA-GOx is highly selective towards glucose