• Title/Summary/Keyword: earth and space

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Shock waves in and around clusters of galaxies

  • Hong, Sung-Wook E.;Ryu, Dong-Su;Kang, Hye-Sung
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.43.2-43.2
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    • 2012
  • We examine the distribution and properties of shock waves within a couple of Mpc from cluster center with single-level grid simulations using up to 20483 grid zones. The effects of cooling/heating and feedbacks from galaxies are also incorporated. There are two different populations of shocks, merger shocks and accretion shocks. We discuss the manifestation of shocks through radio relics.

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A Study on the Site analysis of Jongmyo area -With Feng-shui theory and Geomagnetic Field

  • Han, Jong-Koo;Park, Tong-So
    • KIEAE Journal
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    • v.2 no.4
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    • pp.41-47
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    • 2002
  • East Asian explain the changes of substance happened on earth and those of human life with the conceptual frame of "Gi-ki"(地氣; earth vital energy) and organize them by the system of "Feng-shui(風水) theory. The core of Feng-shui theory is reading the expression of the nature and feeling the Gi-ki from the expression. One of the properties of the earth is that the earth has a magnetic field associated with it- the Geomagnetic field. The geomagnetic field is produced by a combination of the effects of electric currents in the earth's liquid core, the magnetization of crustal rocks, external electric current systems that surround the earth and currents induced in the outer layers of the earth by magnetic field variations. The sameness of logic between Feng-shui and geopathic zones is that both are concerned with the discrimination of site and the energy of places, in other words both disciplines are concerned with how the environment can influence people. In this context the operation of Gj-ki can be related with the effect caused by geomagnetic field on site. In this study Jongmyo(宗廟), one of the representative traditional architecture in Korea is selected because the site selection and building layout follows Feng-shui faithfully according to Taejo silok (太祖實錄, Annals of King Taejo). Observing the landforms surrounding Jongmyo, Jongmyo is apparently located in auspicious places named Gumge Poranhyoeng(金鷄抱卵形, a Feng-shui landscape of golden hen sitting on eggs). The geomagnetic investigation of Jongmyo shows that the geomagnetic values of Toekan(the space near Hyeol) are relatively high and uniform and those of Sangweoldae and Haweoldae are decreased in accordance with the distance. The result shows that there is possibility that Feng-shui has scientific basis related with geomagnetic field. Feng-shui theory can suggest a direction for designing the sustainable building for living with nature.

Development of Soil-cement in Earth-block Materials

  • Wiwattanachang, N;Maneein, N;Parwong, T;Nummeesri, K
    • International Journal of Advanced Culture Technology
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    • v.3 no.1
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    • pp.78-85
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    • 2015
  • In Thailand, the electricity consumption is very high with the intention of reduce high temperature in the building. Since 2000, a lot of people paying attention to Green-Building concept. A similar concept is natural building, which is usually on a smaller scale and tends to focus on the use of natural materials that are available locally. Therefore, the Earth-Block (EAB) product is appropriated approach to reduce energy consumption in the buildings. The EAB is produced with environmentally friendly process, which does not release harmful pollution and effective cost. The main significant character is durable materials for building construction. This study aims to develop the new thermal insulation by using soil-cement with vetiver grass fibre. Additionally, it describes the innovative systems used in production of EAB materials by mixing the soil-cement with vetiver grass fibre. This paper reveals lowest costs, space configurations changing and greater design flexibility for constructing the building.

A Case Study on the Utilization of Underground Building (지중건축의 활용에 관한 사례연구)

  • Suh, Eung-Chul;Lim, Sang-Hoon;Jang, Moon-Seok;Yoo, Heon-Hyung
    • KIEAE Journal
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    • v.1 no.1
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    • pp.17-26
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    • 2001
  • The purpose of this study is to develop an underground Building. Population tends to concentrate in large cities. In result, the cities lacks housings. Underground space may be a attractive space by being able to gain alternative energy and get a cheap site, protect environment at the same time. The earth or ground is a useful medium for a long-term heat source and storage of it's heat. Also the underground space has the status of stabilization, the lower heating load and the similar heat transfer coefficient of the inside wall surface comparing to that of residential space. Utilization of underground space has many advantages to cope with lack of building sites and energy conservation, etc. As a result, it is expected to provide a useful information for the practical use of Underground building.

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Preliminary Results of Tissue-Equivalent Proportional Counter (TEPC) Dosimeter for Measuring In-Situ Aviation Radiation

  • Nam, Uk-won;Park, Won-kee;Hwang, Junga;Sohn, Jongdae;Moon, Bongkon;Kim, Sunghwan
    • Journal of Astronomy and Space Sciences
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    • v.37 no.4
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    • pp.249-255
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    • 2020
  • We develop the tissue-equivalent proportional counter (TEPC) type's space radiation dosimeter to measure in-situ aviation radiation. That was originally developed as a payload of small satellite in the low-earth orbit. This dosimeter is based on a TEPC. It is made of an A-150 tissue-equivalent plastic shell of an internal diameter of 6 cm and a thickness of 0.3 cm. TEPC is filled with pure propane at 13.9 torrs to simulate a cell diameter of 2 ㎛. And the associated portable and low power electronics are also implemented. The verification experiments have been performed by the calibration experiments at ground level and compared with Liulin observation at aircraft altitude during the flight between Incheon airport (ICN) and John F. Kennedy airport (JFK). We found that the TEPC dosimeter can be used as a monitor for space radiation dosimeter at aviation altitude based on the verification with Liulin observation.

NEW TIMES OF MINIMUM AND A PERIOD CHANGE OF GO CYGNI

  • Oh, Kyu-Dong;Ra, Kee-Suk
    • Journal of Astronomy and Space Sciences
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    • v.15 no.1
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    • pp.69-74
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    • 1998
  • Two colour(B & V) photoelectric observations of EB-type eclipsing binary GO Cyg were carried out for 15 nights during October and December 1996. Three new times of minimum derived from our own observations are presented. With these and previously published times, the period variation is studied, and a continuous period increase of $dP/dt{\approx}1.51{\times}10^{-7}d/yr$ is estimated from the quadratic ephemeris.

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ULTRAVIOLET FLUX VARIATION OF EPSILON AURIGAE

  • Kang, Young-Woon
    • Journal of Astronomy and Space Sciences
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    • v.7 no.1
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    • pp.57-69
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    • 1990
  • The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 $AA$ to 3050 $AA$. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

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A Study on the Self-contained Earth Retaining Wall Method Using Bracing (브레이싱을 이용한 자립식 흙막이 공법에 관한 연구)

  • Kim, Jong-Gil
    • Journal of Digital Convergence
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    • v.17 no.3
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    • pp.205-213
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    • 2019
  • In a construction site, excavation work has a close relation with temporary earth retaining structure. In order to build the underground structure most effectively in a narrow space, prevent soil relaxation of the external behind ground in excavation work, and maintain a ground water level, it is required to install a temporary earth retaining structure that secures safety. To prevent soil washoff in underground excavation work, the conventional method of temporary earth retaining structure is to make a temporary wall and build the internal support with the use of earth anchor, raker, and struct for excavation work. RSB method that improves the problem of the conventional method is to remove the internal support, make use of two-row soldier piles and bracing, and thereby to resist earth pressure independently for underground excavation. This study revealed that through the field application cases of RSB method and the measurement result, the applicability of the method for installing a temporary earth retaining structure, the assessment result, and displacement all met allowable values of measurement, and that the RSB method, compared to the conventional method, improved constructability and economy.