Efek Kebocoran Beamtube Dan Pipa Primer Penukar Panas Pada Suatu Model Reaktor Riset 1 Mw Berbahan Bakar Tipe Silinder

Telah dilakukan analisis transien menggunakan program komputer RELAP5/Mod3.2 terhadap model reaktor riset berbahan bakar tipe silinder daya 1 MW dan diasumsikan mengalami kebocoran pada beamtube, pipa cold leg, dan pipa hot leg. Berdasarkan hasil analisis diketahui reaktor mencapai kestabilan pada daya 1 MW adalah 1650 detik setelah kekritisan. Pada kondisi stabil suhu pusat dan suhu kelongsong bahan bakar pada kanal terpanas, serta suhu air pendingin primer keluar dari kanal terkait berturut-turut adalah 529,35 OC, 98,37 OC, 81,27 OC. Pada 7,3 detik setelah beamtube bocor, atau 5,1 detik setelah pipa cold leg bocor, atau 6,2 detik setelah pipa hot leg bocor reaktor scram karena level air tangki telah turun 0,5 m. Penurunan air tangki ini terhenti pada level 0,959 m ketika 97,7 detik setelah beamtube bocor, atau pada level 1,252 m ketika 76,4 detik setelah pipa cold leg bocor, atau pada level 1,252 m ketika 78,6 detik setelah pipa hot leg bocor. Pada kondisi ini suhu pusat dan suhu kelongsong bahan bakar pada kanal terpanas, serta suhu air pendingin primer keluar dari kanal terkait berturut-turut adalah 96,25 OC, 89,63 OC, 78,96 OC untuk kebocoran beamtube, atau 87,12 OC, 78,31 OC, 69,10 OC untuk kebocoran pipa cold leg, atau 87,32 OC, 78,54 OC, 69,43 OC untuk kebocoran pipa hot leg. Berbeda dengan kebocoran pada pipa cold leg dan pipa hot leg, suhu-suhu tersebut pada kebocoran beamtube cenderung terus naik karena sisa panas peluruhan, dan air tangki yang tersedia tidak mampu mengambil panas tersebut secara maksimal, sehingga diperlukan sistem pendinginan teras darurat (SPTD) untuk mendinginkannya

Distribusi Foraminifera Bentik di Perairan Aceh

Perairan Aceh termasuk Pulau Weh, Pulau Breuh dan Pulau Penasi merupakan area terluar di sisi barat Kepulauan Indonesia yang menghadap ke Samudera Hindia. Wilayah ini sangat menarik bagi para peneliti terutama setelah kejadian tsunami pada tahun 2004. Tujuan dari penelitian adalah untuk mengetahui distribusi foraminifera sebagai organisme yang sensitif terhadap Perubahan lingkungan. Sebanyak 32 contoh sedimen diambil pada kedalaman 7- 170 meter dan terpilih 11 contoh untuk studi foraminifera. Hasil penelitian menunjukkan bahwa ada 45 spesies foraminifera bentik yang sangat berlimpah, terdiri atas 28 spesies anggota Subordo Rotaliina, Miliolina (7 spesies) dan Textulariina (10 spesies). Amphistegina papilosa dijumpai dalam jumlah sangat berlimpah dan tersebar merata yang memberi indikasi kondisi lingkungan terumbu karang baik. Ammonia tepida sangat dominan (47%) di sebelah utara Pulau Weh (S30) dibandingkan dengan spesies lain. Di bagian Timur Pulau Penasi, ditemukan cangkang foraminifera dalam kondisi rusak dalam jumlah berlimpah yang dapat dikaitkan dengan arus kuat di lokasi ini. Kata kunci : foraminifera bentik, distribusi, perairan Aceh The Aceh waters including Weh, Breuh and Penasi islands are the outer parts of northwestern Indonesia that facing the Indian Ocean. This area is interested for many scientists especially after tsunami in 2004. The purpose of this study is to establish the distribution of benthic foraminifera as a sensitive indicator of environmental changes. Thirty two (32) surface sediment samples were collected at the water depth of 7-170 m and eleven samples were selected for foraminiferal study. The results show 45 species of benthic foraminifera very abundantly and consists of 28 species belong to Suborder Rotaliina, Miliolina (7 species) and Textularia (10 species). Amphistegina papilosa is found abundantly and widely distribution that provide an indication of good reef environments. Ammonia tepida is very dominant(47%) in the northern part of Weh island compared with other species. Abnormal shells of foraminifera were found abundantly in the eastern part of Penasi Island that related to strong current in this area. Keywords: benthic foraminifera, distribution, Aceh water

On a Site of X-ray Emission in AE Aquarii

An analysis of recently reported results of XMM-Newton observations of AE Aqr within a hypothesis that the detected X-ray source is located inside the Roche lobe of the white dwarf is presented. I show this hypothesis to be inconsistent with the currently adopted model of mass-transfer in the system. Possible solutions of this problem are briefly discussed.Comment: 4 pages, accepted for publication in ApJ Letter

Evaluation of fatty acid profile with special reference to hypertension intake from marine edible fishes

The present study describes the changes in fatty acid profile in hypertension patients by up taking the marine edible fishes Elutherenema tetradactylum, Sphyraena obtusata and Siganus javus because these marine edible fishes are rich in ? –fatty acids.  In this study the total cholesterol, HDL and LDL were significantly decreased from 211.9 – 202.1 mg/dl, 177-159.6 mg/dl. The palmitic acid (C16:0) was found significantly higher in all of peoples compared with other SFAs. This study revealed that the most abundant in individual FAs 16:0,18:0,18:1 n9 and 20:2 n6 were present in blood in both before and after dietary intake. The minimal changes of SFAs levels were decreased averagely from 59.2 to 52.2%. In addition to above PUFAs also increased from 27.7-30.5%. The essential FAs like ALA (C18:3n3), EPA (C20:5n3) and DHA (C22:6n3) were accounting in the range of 2.64-2.92%, 3.67-3.94% and 3.65-4.38%. Omega – 6/3 ratio were recorded from 1.77-2.45%. This study proves the marine edible fishes reduce the hypertension of the patients. Keywords: Edible fishes, ? –fatty acids, SFAs, HDL and LD

Fattening of mud crab: an approach of aquasilviculture in Andaman Islands

During September - December 2004, mud crab fattening was attempted in tide-fed earthen ponds in Lakshmipur (North Andaman) and Bamboo Tickri (Middle Andaman) with mangroves such as Rhizophora mucronata, R. apiculata and Avicennia marina, covering 60 to 80% of the total pond area. Water crabs of Scylla tranquebarica, S. olivacea and S. serrata, each weighing 500 - 1500 g were stocked in the pond at a density of 0.5 kg/m2 with suitable hideouts to reduce cannibalism. In 30 to 35 days, 85% survival was obtained with 8% weight increment. This paper outlines the measures that may be adopted for practicing aquaculture in mangroves

Assessment of post tsunami coral reef resource in Pongi Balu coast, south Andaman Islands

In the present study, an assessment of the status of coral reefs along the Pongi Balu coast, south Andaman Islands, which is a part of the Mahatma Gandhi Marine National Park, has been made by scuba diving, low draft glass-bottom boat and visual interpretation in some places during low-tide condition. The coral reef boundaries have been accurately determined with the help of a low draft glass-bottom boat fitted with a real time kinematics global positioning system, and the existing coral reefs map of the area has been updated using the geographic information system technique. A total of 161.6 ha of previously existed live coral reefs were surveyed along the Pongi Balu coast and out of that ‘live coral’ was found over 81.4 ha and ‘dead coral’ was found over 60.6 ha whereas 19.6 ha area was found to have been lost from the existing coral reefs and categorized as ‘no coral’. The study highlights a few natural and anthropogenic factors affecting the existing coral reefs and hindering the re-establishment of coral reefs in the study area

A promising exponentially-fitted two-derivative Runge–Kutta–Nyström method for solving y′′=f(x,y): Application to Verhulst logistic growth model

Explicit exponentially-fitted two-derivative Runge–Kutta–Nyström method with single -function and multiple third derivatives is proposed for solving special type of second-order ordinary differential equations with exponential solutions. B-series and rooted tree theory for the proposed method are developed for the derivation of order conditions. Then, we build frequency-dependent coefficients for the proposed method by integrating the second-order initial value problem exactly with solution in the linear composition of set functions and with . An exponentially-fitted two-derivative Runge–Kutta–Nyström method with three stages fifth order is derived. Linear stability and stability region of the proposed method are analyzed. The numerical tests show that the proposed method is more effective than other existing methods with similar algebraic order in the integration of special type of second-order ordinary differential equations with exponential solutions. Also, the proposed method is used to solve a famous application problem, Verhulst logistic growth model and the result shows the proposed method still works effectively for solving this model

Dynamical chaos and power spectra in toy models of heteropolymers and proteins

The dynamical chaos in Lennard-Jones toy models of heteropolymers is studied by molecular dynamics simulations. It is shown that two nearby trajectories quickly diverge from each other if the heteropolymer corresponds to a random sequence. For good folders, on the other hand, two nearby trajectories may initially move apart but eventually they come together. Thus good folders are intrinsically non-chaotic. A choice of a distance of the initial conformation from the native state affects the way in which a separation between the twin trajectories behaves in time. This observation allows one to determine the size of a folding funnel in good folders. We study the energy landscapes of the toy models by determining the power spectra and fractal characteristics of the dependence of the potential energy on time. For good folders, folding and unfolding trajectories have distinctly different correlated behaviors at low frequencies.Comment: 8 pages, 9 EPS figures, Phys. Rev. E (in press

An examination of the clinical outcomes of adolescents and young adults with broad autism spectrum traits and autism spectrum disorder and anorexia nervosa: A multi centre study

Objectives: To compare the clinical outcomes of adolescents and young adults with anorexia nervosa (AN) comorbid with broad autism spectrum disorder (ASD) or ASD traits. Method: The developmental and well‐being assessment and social aptitude scale were used to categorize adolescents and young adults with AN (N = 149) into those with ASD traits (N = 23), and those who also fulfilled diagnostic criteria for a possible/probable ASD (N = 6). We compared both eating disorders specific measures and broader outcome measures at intake and 12 months follow‐up. Results: Those with ASD traits had significantly more inpatient/day‐patient service use (p = .015), as well as medication use (p < .001) at baseline. Both groups had high social difficulties and poorer global functioning (strengths and difficulties questionnaire) at baseline, which improved over time but remained higher at 12 months in the ASD traits group (p = .002). However, the improvement in eating disorder symptoms at 12 months was similar between groups with or without ASD traits. Treatment completion rates between AN only and ASD traits were similar (80.1 vs. 86.5%). Discussion: Adolescents with AN and ASD traits show similar reductions in their eating disorder symptoms. Nevertheless, their social difficulties remain high suggesting that these are life‐long difficulties rather than starvation effects