• Title/Summary/Keyword: Cassini

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Cartographic Characteristics of the 'Carte do Cassini' and Its Place in the Development of Cartography (카시니 지도의 지도학적 특성과 의의)

  • Jung In-Chul
    • Journal of the Korean Geographical Society
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    • v.41 no.4 s.115
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    • pp.375-390
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    • 2006
  • The Carte do Cassini is the first accurate topographic map of an entire country and it influenced enormously in the development of cartography in other countries. The purpose of this paper is to examine the production process and characteristics of the Carte do Cassini, and to and the place of 'Carte de Cassini' in the development of cartography. For this, firstly, the background of French national topographic mapping is examined and scientific work of the Cassini family is resumed. Second, the map production process is considered; location and attribute data collection, copperplate printing, social and economic difficulties. Third, map characteristics such as map projection, sheet numbering system, positional accuracy, legend, typographies, and depiction of cartographic signs are explored. Finally, the influence of the Carte de Cassini on cartographic development and its historical meaning is discussed.

Performance of Roots-type Vacuum Pump with Cassini Oval Lobe Shape (Cassini 형 루츠 진공 펌프의 성능에 관한 연구)

  • Kim, H.J.;Cho, J.H.;Kim, Youn-J.
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.813-818
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    • 2000
  • The objective of this study is to elucidate the characteristic performance of Roots-type vacuum pump with Cassini oval lobe shape. The modelled lobe shape of Roots-type vacuum pump is two-lobe spur gear. The numerical analyses are performed fer leak flows, using 4th-order Runge-Kutta method and are compared with experimental results. Results show that for the case of involute lobe shape the total amount of the leak flow conductance is greater than that of cycloid and Cassini oval lobe shapes.

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Effect of Lobe Shape Variations on the Performance of Roots-type Supercharger (Roots형 과급기 로브 형상 변화가 성능에 미치는 영향)

  • 김윤제;정찰기
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.101-110
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    • 2000
  • A Computer program is developed for creation of a new lobe shaper for Roots-type supercharger. Numerical analyses are preformed for the flowfields in the pocket volumes formed by various lobe shapes. The governing equations for the two-dimensional, turbulent, operational processes in the housing are discretized by the control volume approach that insures the conservative characteristics to be satisfied in the calculation domain, and they are solved by a modified SIMPLE algorithm. Numerical results show that the effects of secondary flow on the leakage flow rate with the Cassini(B) lobe shape is smaller than that of Cassini(A) rotor. But the pocket volume of Cassine(B) lobe is larger than the other lobe shapes.

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Failure Function of Transversely Isotropic Rock Based on Cassini Oval (Cassini 난형곡선을 활용한 횡등방성 암석 파괴함수)

  • Lee, Youn-Kyou
    • Tunnel and Underground Space
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    • v.27 no.4
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    • pp.243-252
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    • 2017
  • Since the failure behavior of transversely isotropic rocks is significantly different from that of isotropic rocks, it is necessary to develop a transversely isotropic rock failure function in order to evaluate the stability of rock structures constructed in transversely isotropic rock masses. In this study, a spatial distribution function for strength parameters of transversely isotropic rocks is proposed, which is based on the Cassini oval curve proposed by 17th century astronomer Giovanni Domenico Cassini to model the orbit of the Sun around the Earth. The proposed distribution function consists of two model parameters which could be identified through triaxial compression tests on transversely isotropic rock samples. The original Mohr-Coulomb (M-C) failure function is extended to a three-dimensional transversely isotropic M-C failure function by employing the proposed strength parameter distribution function for the spatial distributions of the friction angle and cohesion. In order to verify the suitability of the transversely isotropic M-C failure function, both the conventional triaxial compression and true triaxial compression tests of transversely isotropic rock samples are simulated. The predicted results from the numerical experiments are consistent with the failure behavior of transversely isotropic rocks observed in the actual laboratory tests. In addition, the simulated result of true triaxial compression tests hints that the dependence of rock strength on intermediate principal stress may be closely related to the distribution of the microstructures included in the rock samples.

Effects of Lobe Shapes on the Performance of Roots-Type Vacuum Pump (로브 형상 변화가 루츠형 진공 펌프 성능에 미치는 영향)

  • Kim, H.-J.;Kim, Youn J.;Hwang, Y.-K.
    • The KSFM Journal of Fluid Machinery
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    • v.3 no.2 s.7
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    • pp.50-56
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    • 2000
  • The effects of lobe shapes on the leak flow conductance of Roots-type vacuum pump are studied numerically and experimentally. The modelled lobe shape of Roots-type vacuum pump is two-lobe spur gear. The numerical analyses are performed on leak flows in Roots-type vacuum pump. It is numerically calculated using a 4th-order Runge-Kutta method and is compared with experimental results. Results show that for the case of involute lobe shape the total amount of the leak flow conductance is greater than that of cycloid and Cassini oval lobe shapes.

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LINEARLIZATION OF GENERALIZED FIBONACCI SEQUENCES

  • Jang, Young Ho;Jun, Sang Pyo
    • Korean Journal of Mathematics
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    • v.22 no.3
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    • pp.443-454
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    • 2014
  • In this paper, we give linearization of generalized Fi-bonacci sequences {$g_n$} and {$q_n$}, respectively, defined by Eq.(5) and Eq.(6) below and use this result to give the matrix form of the nth power of a companion matrix of {$g_n$} and {$q_n$}, respectively. Then we re-prove the Cassini's identity for {$g_n$} and {$q_n$}, respectively.

Electromagnetic Electron-Cyclotron Wave for Ring Distribution with Alternating Current (AC) Electric Field in Saturn Magnetosphere

  • Haridas, Annex Edappattu;Kanwar, Shefali;Pandey, Rama Shankar
    • Journal of Astronomy and Space Sciences
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    • v.39 no.2
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    • pp.35-42
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    • 2022
  • During their respective missions, the spacecraft Voyager and Cassini measured several Saturn magnetosphere parameters at different radial distances. As a result of information gathered throughout the journey, Voyager 1 discovered hot and cold electron distribution components, number density, and energy in the 6-18 Rs range. Observations made by Voyager of intensity fluctuations in the 20-30 keV range show electrons are situated in the resonance spectrum's high energy tail. Plasma waves in the magnetosphere can be used to locate Saturn's inner magnetosphere's plasma clusters, which are controlled by Saturn's spin. Electromagnetic electron cyclotron (EMEC) wave ring distribution function has been investigated. Kinetic and linear approaches have been used to study electromagnetic cyclotron (EMEC) wave propagation. EMEC waves' stability can be assessed by analyzing the dispersion relation's effect on the ring distribution function. The primary goal of this study is to determine the impact of the magnetosphere parameters which is observed by Cassini. The magnetosphere of Saturn has also been observed. When the plasma parameters are increased as the distribution index, the growth/damping rate increases until the magnetic field model affects the magnetic field at equator, as can be seen in the graphs. We discuss the outputs of our model in the context of measurements made in situ by the Cassini spacecraft.

타이탄 3 마이크론 영역에서 보이는 유기 화합물의 미확인 흡수 밴드 연구

  • Jeong, Ae-Ran;Kim, Sang-Jun
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.89.1-89.1
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    • 2010
  • Cassini/VIMS 관측에 의하면 타이탄의 3 마이크론 파장영역에서 다른 파장 대와 달리 메탄 분자만으로는 관측 값에 맞는 모델을 만들기 힘든 특이한 형태의 흡수 밴드 영역이 발견되었다 (Bellucci et al. 2009, Icarus, v. 201, p. 198). 이 파장영역은 행성뿐만 아니라 ISM (Interstellar Medium)과 혜성 등에서 연구 되고 있는 C-H stretching band와 흡사한 구조를 가지고 있다. 이러한 구조는 타이탄 연무 속에 포함된 유기물질에 의한 것으로 추정된다. 본 연구는 최근까진 개발된 복사방정식 모델과 2006년 Cassini/VIMS가 관측한 고도에 따른 solar occultation 데이터를 비교하여 밴드구조의 실체를 알아보는 것이 주 목적이다. 우리는 고도 별로 다르게 나타나는 흡수밴드의 파장 영역을 세밀히 나눈 후 메탄과 함께 유기물질의 연무가 더해진 모델을 만들었다. 도출된 유기물질의 구조가 관측된 밴드 구조에 미치는 영향을 알아보고 앞으로의 연구 방향을 제시 할 것이다.

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