Characterization of PVDF-HFP-LiCF3S03-Zr02 nanocomposite polymer electrolyte systems

Nanocomposite polymer electrolytes were prepared by incorporating different amounts of zirconium oxide (Zr02) nanofiller to poly(vinylidene fluoride-co exafluoropropylene)-lithium trifluoromethane sulfonate (PVDF-HFP-LiCF3S03). X-ray diffraction (XRD) study has been carried out to investigate the structural features of the electrolyte films while a.c. impedance spectroscopy has been performed to investigate their electrical properties. The conductivity of nanocomposite polymer electrolyte systems is influenced by nanofiller concentration. The increase in conductivity is attributable to the increase in the fraction of amorphous region and the number of charge carriers and vice versa. The highest conductivity obtained is in the order of 10-3 S cm-1 for the system dispersed with 5 wt% of Zr02 nanofiller

Two new xanthones from Artocarpus obtusus

Two new xanthones, pyranocycloartobiloxanthone A (1) and dihydroartoindonesianin C (2), were isolated from the stem bark of Artocarpus obtusus Jarrett by chromatographic separation. Their structures were determined by using spectroscopic methods and comparison with known related compounds. Pyranocycloartobiloxanthone A (1) showed strong free radical scavenging activity by using DPPH assay as well as cytotoxicity towards K562, HL-60, and MCF7 cell lines

Ion conductive polymer electrolyte membranes and simulation of their fractal growth patterns

Due to their high ionic conductivity, solid polymer electrolyte (SPE) systems have attracted wide spread attention as the most appropriate choice to fabricate all-solid-state electrochemical devices, namely batteries, sensors and fuel cells. In this work, ion conductive polymer electrolyte membranes have been prepared for battery fabrication. However, fractals were found to grow in these polymer electrolyte membranes weeks after they were prepared. It was believed that the formation of fractal aggregates in these membranes were due to ionic movement. The discovery of fractal growth pattern can be used to understand the effects of such phenomenon in the polymer electrolyte membranes. Digital images of the fractal growth patterns were taken and a simulation model was developed based on the Brownian motion theory and a fractal dialect known as L-system. A computer coding has been designed to simulate and visualize the fractal growt

The effect of video based mobile learning on students’ writing skill

Mobile learning is the acquisition of any knowledge or skill in the process of learning and teaching through accessing communications and multimedia, such as video, as the main tool and mobile technologies can be used anywhere, anytime. Mobile technology has helped the activity of teaching, especially the teaching of English in secondary schools. It has facilitated learning and accelerated acceptance by students. A study conducted to find out the effects of video-based mobile learning on students’ writing skills in Indonesia examined limits on content and mechanics in writing based on a module used in the English book at Grade 10. The participants of the study comprised 80 students. The data were analyzed using descriptive and inferential statistics including means, standard deviations and t-tests. The video based mobile learning activity conducted has supported teachers in encouraging students to use higher-order thinking skills to solve problems that are relevant to their daily lives. It has allowed students to assess themselves, and they were able to share their learning in the home through mobile learning