Iradiasi Neutron Pada Bahan Ss316 Untuk Pembuatan Endovascular Stent

Neutron Irradiation on SS316 Material for Radioactive Endovascular Stent Production. It was reported thatrestenosis could be prevented by radioactive endovascular stent. SS316 material of endovascular stent has beenirradiated at pneumatic rabbit system of G.A. Siwabessy reactor for 5 minutes for producing radioactive stent byneutron activation. After 10 days of decay, the irradiated SS316 was measured by gamma spectrometer. Theradioisotopes of 51Cr, 59Fe and 60Co were detected in the irradiated SS316 with radioactivity of 5990, 107 and 109Bq/mg respectively. The Calculation results showed that radioisotopes of 51Cr, 59Fe and 55Fe were produced by neutronactivation. The radioactivity of 51Cr, 59Fe and 55Fe were 6051, 70 and 110 Bq/mg respectively. In the irradiatedmaterials, the 55Fe was not detected because the radioisotope emitted radiation with very low energy (5.9 keV). It isconsidered that radioisotope of 60Co was produced from cobalt impurity in the SS316

Synchrotron Polarization at High Galactic Latitude

We present preliminary results from mapping the high-latitude Galactic polarization with the Effelsberg Telescope at $\lambda$21 cm. Structures on the resulting maps are mostly on the scale of several degrees. The results show detection of polarization over most of the field, at the level of tens of percent of the synchrotron emission. The evidence of more structure in Stokes Q and U rather than in $\sqrt{Q^2+U^2}$ suggests the existence of Faraday rotation.Comment: To be published in the proceedings of "The Cosmic Microwave Background and its Polarization", New Astronomy Reviews, (eds. S. Hanany and K.A. Olive

The Importance of Islamic Art in Mosque Interior

AbstractMosques, as symbol of Islamic architecture must play an important role in reflecting the superiority of Allah the Almighty. There are many ways in making it successful and one of them is through the high quality of aesthetic value. Aesthetic value in Islamic art and architecture is normally portrayed by the highest degree of motifs and ornamentation. Contemporary mosque designers normally focused on the majestic looks of the exterior part of the mosques and leave the manipulation of the interior space to the users. There are scholars who said that mosques should act as community development centre, some decided on the uniqueness of traditional Malaysian architecture and some believed that mosques must have domes and minarets as symbols of Islamic architecture. This paper realized on the aesthetics and beauty of mosque interior that fulfils the psychological needs of human beings: that is to be inside a beautiful ambience. Ornamentation should be taken as part of mosque components and not as mere decorations done after-thought or filling in the gap. The main objective of the paper is why is it important to focus the ornamentation towards mosque interior so that ornamenting the mosque will not be done uncontrollably and unnecessarily

Geothermal Reservoir Characterization for Steam Field Management in Kamojang Geothermal Field-West Java

Kamojang is the first geothermal field in Indonesia with a vapor dominated system reservoir. Kamojang has been exploited for over 20 years producing about 1100 tons/hour of steam which is equivalent to 140 Mwe electricity energy. This research is aimed to study the reservoir character after 20 years of exploitation and to investigate the effect of reinjection as a artificial recharge for steam input in the future and also the nature of secondary processes in the reservoir using isotope geochemistry tools. The research is conducted by natural isotopes (18O, 2H and 3H) analysis of many sources of water (meteoric, cold spring, fumaroles and shallow groundwater) in the surrounding of Kamojang field and also fluid reservoir to establish fluid reservoir origins and isotopic composition. Gas analysis and isotopes monitoring on the 25 production wells have been conducted every 2-3 years intervals for more than 10 years to investigate the effect of exploitation to the reservoir performance. Tritium radiotracer test with 370 GBq (10 Ci) activity was conducted at the KMJ 15 reinjection well to determine qualitatively and quantitatively the flow of reinjection water to its surrounding producing well (KMJ 11, 14, 17, 18, 26, 17 and 30). Data interpretation and evaluation to determine reinjection water mass recovery and cooling prediction modeling were conducted using ICEBOX program package (TRINV and TRCOOL). Interpretation and evaluation of data concluded that reservoir fluid of Kamojang geothermal field was originated from meteoric water which infiltrated through fault structures at elevation of 1350 m –1650 m above sea level. There is no evidence that the fluid was originated from magmatic water. Reservoir fluid moved both laterally and vertically (deep fluid) with lateral fluid movement from west to the east. The isotope data analysis indicated there is water entry in west-northwest reservoir boundary. Water entry gradually moved from northwest to the southeast (through wells of KMJ 42, 40, 27, 26 and 28). Exploitation effect to ten of the observation wells shows a decrease in w/r ratio and liquid saturation from 35 % in the beginning to about 20,5 % on the average after 20 years of operation. Evaluation with TRINV and TRCOOL program shows that 13,5 % of water reinjected into KMJ 15 reinjection well was recovered in the surrounding production wells. The program model of the reservoir temperature cooling shows that water reinjection with flow rate of 10 kg/sec is very save. After 20 years of reinjection activity, the model predicts a production wells will be cooling of about 6.8oC.Received: 15 January 2009; Revised: 1 May 2009; Accepted: 5 May 200

Geothermal Reservoir Characterization for Steam Field Management in Kamojang Geothermal Field-West Java

Kamojang is the first geothermal field in Indonesia with a vapor dominated system reservoir. Kamojang has been exploited for over 20 years producing about 1100 tons/hour of steam which is equivalent to 140 Mwe electricity energy. This research is aimed to study the reservoir character after 20 years of exploitation and to investigate the effect of reinjection as a artificial recharge for steam input in the future and also the nature of secondary processes in the reservoir using isotope geochemistry tools. The research is conducted by natural isotopes (18O, 2H and 3H) analysis of many sources of water (meteoric, cold spring, fumaroles and shallow groundwater) in the surrounding of Kamojang field and also fluid reservoir to establish fluid reservoir origins and isotopic composition. Gas analysis and isotopes monitoring on the 25 production wells have been conducted every 2-3 years intervals for more than 10 years to investigate the effect of exploitation to the reservoir performance. Tritium radiotracer test with 370 GBq (10 Ci) activity was conducted at the KMJ 15 reinjection well to determine qualitatively and quantitatively the flow of reinjection water to its surrounding producing well (KMJ 11, 14, 17, 18, 26, 17 and 30). Data interpretation and evaluation to determine reinjection water mass recovery and cooling prediction modeling were conducted using ICEBOX program package (TRINV and TRCOOL). Interpretation and evaluation of data concluded that reservoir fluid of Kamojang geothermal field was originated from meteoric water which infiltrated through fault structures at elevation of 1350 m –1650 m above sea level. There is no evidence that the fluid was originated from magmatic water. Reservoir fluid moved both laterally and vertically (deep fluid) with lateral fluid movement from west to the east. The isotope data analysis indicated there is water entry in west-northwest reservoir boundary. Water entry gradually moved from northwest to the southeast (through wells of KMJ 42, 40, 27, 26 and 28). Exploitation effect to ten of the observation wells shows a decrease in w/r ratio and liquid saturation from 35 % in the beginning to about 20,5 % on the average after 20 years of operation. Evaluation with TRINV and TRCOOL program shows that 13,5 % of water reinjected into KMJ 15 reinjection well was recovered in the surrounding production wells. The program model of the reservoir temperature cooling shows that water reinjection with flow rate of 10 kg/sec is very save. After 20 years of reinjection activity, the model predicts a production wells will be cooling of about 6.8oC.Received: 15 January 2009; Revised: 1 May 2009; Accepted: 5 May 200