1,720,972 research outputs found
ANALISIS PARAMETER KINETIKA TERAS HTR-10 DARI ASPEK STATIS DAN TRANSIEN
Full text linkANALISIS PARAMETER KINETIKA TERAS REAKTOR HTR-10 DARI ASPEK STATIS DAN TRANSIEN. HTR (High Temperature Reactor) merupakan salah satu tipe reaktor nuklir yang menggunakan moderator grafit dan berpendingin gas helium. Indonesia sedang merencanakan untuk membangun Reaktor Daya Eksperimental (RDE) yang merupakan reaktor tipe HTR dengan daya nominal 10 MWth. Tujuan penelitian ini adalah untuk melakukan analisis keselamatan desain reaktor tipe HTR untuk mendukung program pembangunan RDE tersebut. Sebagai objek penelitian digunakan data HTR-10 Tiongkok dengan pertimbangan bahwa spesifikasi teras tersebut hampir sama dengan teras RDE. Perhitungan parameter kinetika sebagai fungsi temperatur bahan bakar dilakukan dengan paket program SRAC2006 modul CITATION terhadap model teras geometri 2-dimensi arah R-Z. Input data berupa tampang lintang makroskopik homogenisasi bahan bakar bola dan pendingin helium diperoleh melalui perhitungan menggunakan modul PIJ melalui metode heterogenitas ganda. Analisis dilakukan terhadap parameter kinetika teras HTR-10 dalam kondisi statis dan transien. Dari hasil perhitungan diketahui bahwa pada kondisi transien akibat kenaikan temperatur bahan bakar, maka nilai parameter kinetika teras HTR-10 antara lain, umur neutron serempak, waktu generasi neutron serempak, fraksi neutron kasip, dan fraksi neutron kasip tiap group akan mengalami sedikit penurunan / lebih kecil, sedangkan nilai konstanta peluruhan neutron kasip tiap group hampir tidak mengalami perubahan / tetap. Sehingga perubahan daya teras reaktor masih akan berlangsung secara normal.Kata kunci: SRAC2006, heterogenitas ganda, HTR-10, parameter kinetika, transie
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
ANALISIS MODEL TERAS 3-DIMENSI UNTUK EVALUASI PARAMETER KRITIKALITAS REAKTOR PWR MAJU KELAS 1000 MW
Full text linkSetelah kejadian Fukushima, penggunaan sistem keselamatan pasif menjadi persyaratan yang penting untuk PLTN. PLTN jenis PWR maju kelas 1000 yang didesain oleh Westinghouse, AP1000, memiliki fitur keselamatan pasif disamping sederhana dan modular. Sebelum memilih suatu PLTN, maka perlu dilakukan suatu evaluasi terhadap parameter desainnya. Salah satu parameter yang penting dalam keselamatan adalah kritikalitas teras. Permasalahan pokok dalam mengevaluasi parameter kritikalitas teras AP1000 tidak adanya data komposisi material SS304 dan H2O di daerah reflektor dan diameter penyerap SS304. Dengan demikian tujuan penelitian ini adalah mendapatkan model teras 3-dimensi AP1000 dan siap diaplikasikan dalam evaluasi parameter kritikalitas teras. Hasil perhitungan menunjukkan bahwa komposisi terbaik SS304 dan H2O di reflektor teras bagian atas dan bawah masing-masing 50 vol%, sedangkan diameter penyerap SS304 adalah 0,960 cm. Evaluasi konsentrasi boron kritis menunjukkan perbedaan yang signifikan dengan nilai desain. Meskipun penyebab utama dari perbedaan ini belum diketahui, akan tetapi dapat dibuktikan bahwa konsentrasi boron kritis sangat sensitif dengan densitas UO2. Untuk reaktivitas padam, reaktor AP1000 memiliki margin subkritikalitas teras yang besar untuk satu siklus operasi. Dengan demikian teras yang diusulkan dapat digunakan sebagai acuan untuk evaluasi parameter teras lainnya atau perangkat analitis lainnya dalam rangka mengevaluasi desain reaktor AP1000.Kata kunci: AP1000, kritikalitas, konsentrasi boron kritis, reaktivitas padam After the Fukushima accident, the use of passive safety system becomes an important requirement for the nuclear power plant (NPP). The advanced PWR NPP with 1000 MW (electric) class, designed by Westinghouse, AP1000, a reactor with the passive safety features as well as simple and modular. Before selecting a nuclear power plant, there should be an evaluation of the design parameter. One important parameter in criticality safety is core criticality parameters. Main problem in evaluating the core criticality parameters of the AP1000 is that the material composition data SS304 and H2O in the reflector (top and bottom of core) and the diameter of SS304 absorber are not provided. Therefore the objective of this research is to obtain a three-dimensional model of AP1000 core and it can be applied in the evaluation of the core criticality parameters. The calculation results show that the optimum composition of SS304 and H2O in the top and bottom reflector is 50 vol%, respectively, while the diameter of the SS304 absorber is 0.960 cm. Evaluation of the critical boron concentration showed a significant difference to the design value. Although the main cause of this difference is not clear, but it can be proved that the critical boron concentration is very sensitive to the density of UO2. For shutdown reactivity, AP1000 has a large subcriticality margin for one operating cycle. It can be concluded that the proposed 3-imensional core model of AP1000 can be used as a reference for other core parameter calculation or other analytical tools in order to evaluate the AP1000 reactor design. Keywords: AP1000, criticality, critical boron concentration, shutdown reactivit
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
MANAJEMEN TERAS RSG-GAS BERBAHAN BAKAR SILISIDA 4,5 DAN 4,8 G U/CC
No full textMANAJEMEN TERAS RSG-GAS BERBAHAN BAKAR SILISIDA 4,5 DAN 4,8 G U/CC. Dengan telah digunakannya bahan bakar silisida 2,96 g/cc di teras RSG-GAS dan telah dilakukannya beberapa penelitian mengenai penggunaan bahan bakar silisida 3,55 g/cc, studi mengenai kemunginan penggunaan bahan bakar silisida dengan densitas yang lebih tinggi perlu dilanjutkan. Densitas uranium maksimum bahan bakar silisida yang telah terkualifikasi adalah sebesar 4,8 g U/cc. Penelitian sebelumnya menyimpulkan bahwa penggunaan bahan bakar silisida dengan densitas 3,55 g U/cc dapat menaikkan panjang siklus sebesar 7 (tujuh) hari daya penuh (210 MWD) dengan tanpa mengubah material dan konfigurasi teras. Namun akan terjadi penurunan margin padam sebesar 50% dibanding dengan desain awal. Dengan demikian penggunaan bahan bakar silisida dengan densitas uranium lebih besar dan 3,55 g U/cc di teras RSG-GAS harus menambahkan batang kendali pengaman (BKP). Penelitian yang dilakukan ialah untuk mendapatkan teras setimbang RSG-GAS silisida berdensitas 4,5 dan 4,8 g U/cc. Perhitungan sel menggunakan paket program WIMS/D4 dan perhitungan teras menggunakan paket perhitungan difusi 2 dimensi BATAN-EQUIL-2D. Perhitungan teras dilakukan untuk kondisi teras setimbang tanpa dan dengan BKP. Hasil perhitungan menunjukkan bahwa teras tanpa BKP tidak dapat dioperasikan, akan tetapi dengan menambahkan BKP, pada posisi B-3 dan G-10, reactor dapat dioperasikan dengan panjang siklus antara 1200-1270 MWD dan 1400MWD masing-masing untuk teras silisida 4,5 dan 4,8 g U/cc
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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