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Hasil Pencarian

Ditemukan 139 dokumen yang sesuai dengan query
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Teguh Budi Prayitno
"ABSTRACT
This paper studies the effect of higher order derivative tensor in the Einstein field equations for vacuum condition on the planet perihelion precession. This tensor was initially proposed as the space-time curvature tensor by Deser and Tekin on discussions about the energy effects caused by this tensor. However, they include this tensor to Einstein field equations as a new model in general relativity theory. This is very interesting since there are some questions in cosmology and astrophysics that have no answers. Thus, they hoped this model could solve those problems by finding analytical or perturbative solution and interpreting it. In this case, the perturbative solution was used to find the Schwarzschild solution and it was also applied to consider the planetary motion in the solar gravitational field. Furthermore, it was proven that the tensor is divergence-free in order to keep the Einstein field equations remain valid. "
[Direktorat Riset dan Pengabdian Masyarakat UI;Universitas Negeri Jakarta. Fakultas Matematika dan Ilmu Pengetahuan Alam;Universitas Negeri Jakarta. Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Negeri Jakarta. Fakultas Matematika dan Ilmu Pengetahuan Alam], 2011
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Wahlin, Lars
Colorado: Colutron Resesrch, 1985
523.1 WAH c
Buku Teks  Universitas Indonesia Library
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Rosa Dian Teguh Pratiwi
"

Dosimetri lapangan kecil dan non-standar yang berkaitan dengan penggunaan berkas Flattening Filter Free (FFF) merupakan sebuah tantangan karena adanya efek pertubasi yang disebabkan oleh desain detektor. Fenomena ini mendorong para peneliti untuk melakukan studi lebih lanjut mengenai respon detektor. Pada penelitian ini, dilakukan pemisahan radiasi hamburan dan berkas primer dari berkas FFF 6 MV untuk mempelajari respon detektor pada masing-masing kondisi pengukuran sehingga peranan setiap fenomena yang mempengaruhi respon detektor dapat dipahami dengan lebih baik. Detektor bilik ionisasi dan film Gafchromic digunakan pada tiga konfigurasi pengukuran yang merepresentasikan pengukuran lapangan terbuka dan pendekatan terhadap pengukuran dalam berkas primer dan radiasi hamburan, dirincikan sebagai berikut: (i) detektor diposisikan di bawah blok baja, sehingga detektor hanya terpapar radiasi hamburan; (ii) detektor diposisikan dalam mini phantom, sehingga detektor terpapar berkas primer dengan radiasi hamburan minimum; (iii) detektor diposisikan pada lapangan standar terbuka yang merupakan superposisi berkas primer dan radiasi hamburan. Hasil pengukuran menunjukkan bahwa respon detektor bergantung pada desain detektor (seperti ukuran volume aktif) terutama pada lapangan kecil. Respon pada lapangan terbuka dapat direproduksi dari konfigurasi berkas primer dan hamburan dengan diskrepansi 1,0 – 36%. Efek volume averaging dan efek pertubasi detektor yang mempengaruhi respon detektor dapat teramati pada konfigurasi berkas hamburan. 


Small fields dosimetry which related to the use of FFF beams is a great challenge because of perturbation effects caused by the size of the detector’s active volume or detector’s materials. This phenomenon encourages researchers to do further study about detectors response. In this work, scatter and primary radiation from 6 MV FFF beams were studied to evaluate the detectors’ response in small fields for a better understanding in the contribution of every phenomenon. Ion chamber and Gafchromic films were used in three measurement configurations representing open field measurement and approximations of both primary and scatter part of the beam, described as follows: (i) detectors positioned under steel block, exposing the detectors only to scatter part of radiation field, (ii) detectors positioned inside mini phantom, approximating the detectors response to primary radiation with minimum scatter, (iii) detectors positioned in the standard open field, which was the superposition of the primary and scatter radiation. The results showed that detector responses were heavily depended on its design (i.e. active volume) especially in small beams. The response in the open field could be reproduced from the blocked and primary beam set-up with the discrepancy ranging from 1.0% to 36%. Moreover, the volume averaging and detectors’ perturbation effects affecting the detector response could be observed in blocked beam.

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2019
T52437
UI - Tesis Membership  Universitas Indonesia Library
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Zeilik, Michael
Philadelphia: Saunders College, 1992
520 ZEI i
Buku Teks  Universitas Indonesia Library
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Smart, W.M.
New York: Cambridge University, 1962
522.7 SMA t
Buku Teks  Universitas Indonesia Library
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Xie, Shilong
Taibei : Zheng Zhong Book, 1979
SIN 520 XIE t
Buku Teks  Universitas Indonesia Library
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"Le eclissi di sole e di luna sono fra gli spettacoli più avvincenti della Natura; questo libro è una guida completa alla loro osservazione e spiega come cercare, vivere e fotografare questi eventi senza necessariamente essere astrofili esperti.
Cosa posso osservare durante un’eclisse? Da dove? E quando? Un’accurata selezione delle 10 eclissi imperdibili da qui al 2050 chiude l’opera, aiutando il lettore nella pianificazione delle osservazioni. "
Milan: Springer, 2012
e20426643
eBooks  Universitas Indonesia Library
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"Grazie ad avventurosi studi fu possibile dimostrare un secolo fa che parte della radiazione naturale che si osserva sulla Terra è di natura extraterrestre: era la scoperta dei cosiddetti “raggi cosmici”, particelle che arrivano da misteriosi acceleratori nell’universo, probabilmente buchi neri supermassicci e resti di supernova, a energie anche centinaia di milioni di volte di quelle a cui riusciamo a produrle con i più potenti acceleratori della Terra. A cent’anni dalle prime scoperte questo libro si propone, con l’aiuto di documenti scoperti recentemente, di raccontare la vera storia di questa appassionante avventura scientifica e le frontiere dell'esplorazione dei raggi cosmici."
Milan: Springer, 2012
e20426647
eBooks  Universitas Indonesia Library
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New York: McGraw-Hill, 1997
R 520.3 MCG
Buku Referensi  Universitas Indonesia Library
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New York: McGraw-Hill, 2003
R 520.3 MCG
Buku Referensi  Universitas Indonesia Library
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