Vol. 37 No. 2 (2005)

Ti1-xCoxO2 thin films have been deposited on Si substrate by MOCVD technique. Thin films were synthesized by a single plane orientation structure of anatase-213 at various to Co concentartions up to 5,77%. Photoluminescence emission spectra of thin films showed a maximum peak at the energy of 2.8 eV. These energies did not change when increasing Co concentration in the Ti1-xCoxO2 thin films up to 5.77%. The patterns of spectrum emission only differ on the intensity and broadness of spectra. Broading occurs towards the higher energy of 2.8 eV, while the intensities were increased with…

Recently, polymeric insulating materials are widely used for high voltage cables. During operation, a field enhancement sites such as void and protrusion may exist in the polymeric insulation. Degradation of the insulation may occur and the so-called electrical treeing will grow. The electrical treeing appears in the polymeric insulation in the form of tree-like structure with very fine cylindrical channels similar to the trunks and branches in an actual tree. The appearance of an electrical treeing is a sign that a harmful degradation is developing in the insulation. In order to avoid the…

Technical problems of land boundary between Indonesia and Papua New Guinea are related to delimitation and demarcation process that has been done by two countries. The process did not explicitly the datum and reference frame being used in reconstructing of monuments border pursuant to the agreement of meridian in article-1 of boundary agreement of 1973. The uncertainty about the datum caused demarcation process has been done using different datum. The datums are astronomic and geodetic datum. The combination of the coordinate derives from respectively datum to reconstruct the agreement of…

At present, structural designing in Indonesia uses the value of reduction factor (φ) according to LRFD-AISC regulation (Load and Resistance Factor Design – American Institute of Steel Construction). It is understood that different condition in Indonesia requires different approach, therefore this research attempted to determine a specific value of reduction factor (φ).The research observes the compression and flexural behavior of profile steel boxes (2x4) cm with length 75 cm and 65 cm for compression and flexural test, respectively. This test collects resistance data that are stress,…

In this paper, optical and digital methods are combined to improve the quality of the image obtained through a scattering medium. The optical method, using simply an imaging positive lens and a small circular spatial filter, succeded in the first stage to form an observable image.Two criteria were adopted to evaluate the quality of the image in the optical method. The first is Peak Signal-to-Noise Ratio (PSNR), the second is the correlation coefficient between the original image and the processed scattered image. It was found that PSNR decreased at a larger diameter of the spatial filter. The…

Poly(R,S)-β-hydroxybutyrate (PHB) and its copolymers with δ-valerolactone were synthesized by ring-opening copolymerization of (R,S)-β-butyrolactone (β-BL) and δ-valerolactone (δ-VL) monomers in the presence of a tetraisobutyldialuminoxane catalyst. The biodegradability of these polymers by using activated sludge was studied in an aerobic medium. The objective of this work was to determine the influence of structure and crystallinity of polymers on their degree of biodegradation and initial degradation rate. It was shown that the degradation rate for bacterial P(R)-HB with 100 % (R)…