ENHANCING GRAPHITIC CARBON CONTENT OF CARBON-BASED ELECTRODE MATERIALS BY PULSED ELECTROPHORETIC DEPOSITION FOR ELECTROCHEMICAL CAPACITOR

Crystallinity of carbon electrode materials and their deposition techniques are the crucial factors for electrochemical capacitor (EC) performance. The present work investigates deposit yield and graphitic content of activated carbon (AC) and CNT coatings deposited by pulsed electrophoretic deposition (EPD). Pulse voltage with pulse separation times of 30 to 50 s, alternated with the long pulse width (i.e. 2.5 min) was applied. Although the pulse separation time at 30 s reduced the CNT coating yield, its graphitic content increased by 40 % as compared to the CNT coating deposited by continuous voltage EPD, as indicated by the IG/ID ratio of Raman spectra. However, graphitic content increase was not observed in the deposition of AC. Consequently, the CNT deposition gained a higher graphitic-nongraphitic content ratio than the AC. This finding opened up the possibility of the EC performance enhancement by the graphitic CNT control in electrode materials through EPD process

Microhardness of Al2O3 nanoparticles added YBa2Cu3O7-delta superconductor prepared using auto-combustion reaction

The effects of Al2O3 nanoparticles on the phase formation, microstructure and microhardness of YBa2Cu3O7-delta superconductor prepared by citrate-nitrate auto-combustion reaction were investigated. In this study, YBa2Cu2O7-delta precursor gels containing different compositions of Al nitrate varied from 0.02 to 0.10 mol were continuously heated at 250 degrees C before automatically combusted into very fine ashes. Calcination process at 900 degrees C for 1 h has transformed these ashes into sample powders. The XRD and EDX results revealed that Al2O3 nanoparticles were yielded as separate phase from YBa2Cu3O7-delta. The nanoparticles were observed homogeneously distributed in <= 0.06 mol samples while agglomerated along YBa2Cu3O7-delta grain boundaries in other samples. The 0.06 mol sample has the highest microhardness compare with the other samples. The Al2O3 nanoparticles by <= 0.06 mol compositions were effectively acted as reinforced phase which prevent further dislocation movements of YBa2Cu3O7-delta grains. As for = 0.06 compositions, agglomeration of Al2O3 nanoparticles may introduce ductility

EFFECT OF DIFFERENT COOKING TEMPERATURE AND ALKALINITY ON MECHANICAL AND MORPHOLOGICAL PROPERTIES OF COMPOSITE SHEET FROM DURIAN SHELL WASTE FIBRE

Temperature and alkalinity are the critical factors that contribute to the successful of soda pulping. These factors influence the length size and interfibre bonding of the fibre. In this paper, durian (Durio zibethinus Murray) shell composite sheet were prepared by conducting chemical pulping through soda method to study the effect of different pulping temperature and % of NaOH on the mechanical and morphological characteristics of durian shell composite sheet. Six sets of composite sheet were produced from six sets of pulping. The pulping processes were conducted at 140, 160 and 170°C with 17, 19 and 21% of active alkali. The mechanical properties of the durian shell composite sheet were analyzed through few standard TAPPI analyses which are tensile, tear, burst, folding endurance and paper bulk thickness. The results show that the highest reading of paper bulk thickness, tensile, tear and burst index, and also folding endurance were achieved at the pulping condition of 170°C with 21% of NaOH with the value of 1.3366 g/cm3, 54.151 NM/g, 6.648 m.Nm2/g, 2.517 k.Pam2/g and 170 no. of fold, respectively. Scanning electron microscopic analysis showed that morphological changes took place depending on the size and arrangement of the fibres in the composites sheet