• Title/Summary/Keyword: light elements

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Risk Assessment of Strong Wind over Industrial Facilities in Shipyards (조선소 시설물의 강풍 위험 평가)

  • Lee, Sung-Su;Kim, Hak-Sun;Lee, Young-Kyu;Shim, Kyu-Cheoul
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.4
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    • pp.21-28
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    • 2009
  • Most of domestic shipyards are located at coastal regions which are affected by typhoons nearly every year. For effectiveness of shipbuilding, shipyards contain many facilities which are light-weighted and affected dominantly by wind. In the present paper, we analyze various wind fields over a shipyard including surrounding topology and structures to evaluate the structural safety of the facilities posed in the strong wind. Extreme wind speed for a study region was estimated by typhoon Monte Carlo simulation and then used for inlet wind speed for CFD analysis for wind load on the facilities. Considering geometrical wind effects, we assess the surface pressure of the elements as the pressure factor, the ratio of surface pressure to dynamic pressure. The results show that the simulated wind speed is greater than the design wind speed for the some facilities because of the shipyard's geometry. It also shows that surrounding topography in coastal area is needed to be considered and adjustment for design wind speed at wind load standard application is necessary for mooring ship and industry facilities.

Design and Development of SMH Actuator System (SMH 액추에이터 시스템 설계 및 개발)

  • Kwon T.K.;Choi. K.H.;Pang. D.Y.;Lee. S.C.;Kim N.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.551-555
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    • 2005
  • This paper presents the temperature-pressure characteristics of SMH actuator using a peltier module. The simple SMH actuator, consisting of the plated hydrogen-absorbing alloy as a power source, Peltier elements as a heat source and a cylinder with metal bellows a functioning part has been developed. The SMH actuator is characterized by its small size, low weight, noiseless operation and a compliance similar to that of the human body. A new special metal hydride(SMH) actuator that uses the reversible reaction between the heat energy and mechanical energy of a hydrogen absorbing ally. It is well known that hydrogen-absorbing alloys can reversibly absorb and desorb a large amount of hydrogen, more than about 1000 times as their own volume. To improve the thermal conductivity of the hydrogen-absorbing alloy, an electro-less copper plating has been carried out. The effects of the electro-less copper plating and the dynamic characteristics of the SMH actuator have been studied. The hydrogen equilibrium pressure increases and hydrogen is desorbed by heating the hydrogen-absorbing alloys, whereas by cooling the alloys, the hydrogen equilibrium pressure decreases and hydrogen is absorbed. Therefor, the SMH actuator has the characteristic of being light and easy to use and so is suitable for use in medical and rehabilitation applications.

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A Study on Several Mineral Elements in Korea Tobacco Leaves (한국산 잎담배 중의 몇가지 무기성분에 관한 조사 연구)

  • Kim, Chan-Ho;Kim, Jeung-Ok
    • Journal of the Korean Society of Tobacco Science
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    • v.1 no.2
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    • pp.103-110
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    • 1979
  • The contents of Sodium, Magnesium, Iron, nickel , Copper, Maganese and Zinc in Korean tobacco leaves Produced in 1978, were investigated. The contents of each mineral element in tobacco leaves of various varieties were as follows ; Mg was 5370$\mu{g}/g-7640\mu{g}/g$, Burley> Flue -cured >Native. Mn was 210$\mu{g}/g-1290\mu{g}/g$, Burley>Flue -cured>Native. Fe was 330$\mu{g}/g-590\mu{g}/g$, Burley>Flue -cured>Native. Zn was 500$\mu{g}/g$ -100, Native > Burley>Flue-cured. Na, Ni and Cu showed no difference between the types. The contents of Ha, Mg, Mn, Ni and Cu were reduced in the order of Heavy 5, 3, 1 and increased in the order of Light 1, 3, 5 grades. The correlation coefficient (r) between Mg and grade in Hicks, SC 72 and HC 2326 were 0.770-0.981, and significance level was 0.1 % .

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Effective Utilization of Hemp Fiber for Pulp and Papermaking (I) -Morphological Characteristics of Hemp Fiber- (펄프.제지용 원료로서의 삼 섬유 이용에 관한 연구(제 1보) -대마 구성 세포의 현미경적 관찰-)

  • Yoon, Seung-Lak;Lee, Myoung-Ku
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.42 no.1
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    • pp.7-12
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    • 2010
  • Morphological characteristics of hemp fiber were investigated using a light microscope in order to provide fundamental data for the use of hemp as a papermaking law material. Phloem of hemp is composed of cortical parenchyma cells and bast fiber with thick walls while xylem is composed of vessel, wood fiber and ray parenchyma cells. Also there are solitary pore and radial pore multiple which exist in diffuse porous pattern. Ray cells consist of uniseriate rays and thin walled ray parenchyma cells. Wood fibers are composed of three types: a large diameter fiber with longer length; a large diameter fiber with shorter length; a small diameter fiber with medium length. Vessel elements are composed of: a medium length one; a longer length one; the one whose both end walls have ligules or tails. Parenchyma cells in xylem and pit parenchyma cells have completely different size and shape. For bast fiber, the average length is about 4.4 mm and the width is about $30.5\;{\mu}m$; for vessel element, $600.0\;{\mu}m$ in length and $493.6\;{\mu}m$ in width; for wood fiber, $1000\;{\mu}m$ and $38.9\;{\mu}m$; for parenchyma cell, $50\;{\mu}m$ and $26.4\;{\mu}m$.

Design and Implementation of 2.4/5 GHz Dual-Band Plate Type Antenna for Access Point of Wireless LAN (2.4/5 GHz 무선 LAN 액세스 포민트용 이중 공진 판형 안테나 설계 및 구현)

  • Lee Won-Kew;Son Ji-Myoung;Han Jun-Hee;Yang Woon-Geun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.5 s.108
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    • pp.401-407
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    • 2006
  • In this paper, we present a small-sized and light weighted dual-band antenna for an access point of 2.4/5 GHz dual-band WLAN(Wireless Local Area Network). The antenna for WLAN should show the characteristic of omni-directional radiation pattern. First, to obtain the omni-directional radiation pattern the proposed dual-band antenna has an orthogonal inverted triangular type element at the center and locates four resonating elements symmetrically around it. Also, for the purpose of easy manufacturing and miniaturization of the antenna, we changed the central element which had the orthogonal inverted triangular type structure into the plate type. Measured $S_{11}$ for the proposed dual-band plate type antenna showed characteristic which was less then -12.8 dB for WLAN frequency bands. Measured results for the maximum gain showed 3.17 dBi at 2.44 GHz, 5.38 dBi at 5.77 GHz with omni-directional radiation pattern. The implemented antennas showed applicable performances for the access point of WLAN.

The Comparative Study on Contemporary Cultural Facilities in the City Environment (도시 환경과 디자인 계획으로 본 현대 문화시설 비교 연구)

  • 김선영
    • Archives of design research
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    • v.16 no.4
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    • pp.323-334
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    • 2003
  • This study examines the multi-functionality of the cultural facilities and explores the architectural characteristics of cultural facilities in city environment. For this purpose, 1 examine the major cultural facilities in USA and Singapore. Recently, the inter-cultural communication methods have been diversified and the cultural facilities need to be designed to effectively accommodate the public's interests in these activities. It is also necessary to reexamine cultural facilities' functions in terms of how the multi-functionality facilities reflect the surrounding environment. This study also sheds a new light on the meaning of the relationships between cultural activity, and the cultural facility design. For this, I primarily look at the various design categories of cultural buildings and their main functions. Finally, I demonstrate how both cultural activity and cultural facility design elements are embodied in the city environment.

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A Study on Rheology Characteristics of Ag Paste for Screen Printing Method for Silicon Solar Cells Electrodes Capable of Forming High Aspect Ratio (고온 소결형 실리콘 태양 전지의 High Aspect Ratio 전극 형성이 가능한 Ag 페이스트의 레오로지 특성 연구)

  • Oh, Tae-Hun;Kim, Sung-Bin;Nam, Su-Yong
    • Journal of the Korean Graphic Arts Communication Society
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    • v.28 no.1
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    • pp.15-24
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    • 2010
  • Photovoltaic solar cells are all in the incident because they are not converted into electrical energy, high-efficiency solar cells in order to reduce the loss of elements must be. Significant factor in the loss of solar cells, optical loss and electrical loss can be divided into. Optical losses occur when the sun will be joined on the surface of the reflection, the shadow loss due to electrodes, and the losses are in the solar wavelengths. Commercialization is currently the most common solar cells on the front of the light incident on the electrode is formed. Therefore, the shadow caused by the electrode to cover the dead area of the sun, due to factors that hinder the absorption of sunlight which is shadowing them and conversion efficiency of solar cells is the inhibition factor. These barriers to eliminate the electrode linewidth reduces the shadowing to reduce, but simply of the electrode line width is reduced electrode area by reducing the series resistance elevates this because to improve the electrode Aspect ratio(height/width) to increase Ag development of paste is required. In this study, aspect ratio of screen-printing method to increase the electrode Ag paste composition of the binder for the characterization of rheology in the shadow of the electrode by reducing the optical loss of the photoelectric conversion efficiency of solar cells to boost the performance measures was. Properties and printability of the paste, the binder resin sintered characteristics that affect the thermal properties are excellent with a good screen printability acrylic resin, ethyl cellulose, using a resin were evaluated. Prepared paste rheology properties, was formed to evaluate the electrode conductivity and aspect ratio.

Growth and Physiological Responses of Two Pine Species Grown under Polluted Ansan Industrial Region (안산 공단지역에 식재된 소나무류 2종의 생장과 생리학적 반응)

  • Jin, Hyun-O;Choi, Dong-Su;Lee, Choong-Hwa;Jeong, Yong-Ho;Koike, Takayoshi
    • The Korean Journal of Ecology
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    • v.28 no.5
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    • pp.321-326
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    • 2005
  • We investigated the effects of pollutants on two pine species (Pinus koraiensis and Pinus rigida) in an industrial region, using a physiological approach. We measured the growth and physiological parameters (photosynthetic activity and chemical contents) of the pine trees in relation to environmental pollutants. The concentrations of manganese (Mn), fluorine (F) and chlorine (CI) in needles of two pine species at the damaged site were significantly higher than those at the control site, and concentrations of essential elements (P) and chlorophyll in needles at the damaged site were significantly lower than at the control site. The light-saturated net photosynthesis $(P_{sat})$, apparent quantum yield $(\Phi)$, carboxylation efficiency (CE) of both pines at the damaged site were significantly lower than those at the control site. The length of shoots and survivorship of needles of two pines at the damaged site were significantly lower than those at the control site. Especially, at damaged site, growth of shoots and needle longevity of P. koraiensis are larger than those of P. rigida.

A Study on the Environmental Education Experience and Environmental Perceptions of Citizens in Daegu (대구시민의 환경교육경험과 환경인식에 대한 연구)

  • Yamada, Keiko
    • Journal of Environmental Science International
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    • v.23 no.8
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    • pp.1469-1480
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    • 2014
  • This study, through the survey of citizens of Daegu in regard to the environment education experience and citizens perception, seeks to identify the order of importance and perception on the severity of environment. The survey has found that 36.4% citizens of Daegu have environment education experience. Those who have experience have high standard of living, live in high population density area and where pollutant generating plants are prevalent. In addition they are likely to live in apartment, are younger, and the higher the education level, more opportunities they have in getting environment education. The study has found that the environment education experience gives noticeable influence on environment perception, environment attitude, and environment activities. Also, those who have the environment education are likely to be interested in environment, know green growth policies, and are positive about local environment activities. Thus, they are willing to participate in activities to improve local environment and have emphasized the need for more environment education. As for what environment elements are most severe, they pointed to the "global warming and climate change" and "everyday garbage" and as for what are important, they chose "drinking water quality" and "global warming and climate change." Based on the study, we came to the conclusion that more environment education should be provided to elevate the interest in environment and subsequently, foster the sense of responsibility and civic mind toward the preservation of environment. In light of above, local governments must expand their supports and fully utilize the Local Agenda 21 to promote the education and increase the perception of citizens on the environment.

A Study on the Development of the Understanding that the Cause of Warm Pathogen Lies in Upper Portion of Body ("온사상수(溫邪上受)" 개념의 형성요인에 대한 고찰)

  • Eun, Seokmin
    • Journal of Korean Medical classics
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    • v.30 no.2
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    • pp.11-29
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    • 2017
  • Objectives : Contemporary researches suspect that, contrary to the past belief, the understanding that the cause of warm pathogen lies in the upper portion of human body is an understanding that had been well-established even before Yetianshi. This new understanding now requires us to contemplate the process of theoretical development which this understanding, termed Onsasangsu, had taken within the boundary of the theory of warm pathogen. This paper aims to shed light on this within the framework that this is the emergence of a new theory of warm pathogen caused by a new understanding of warm pathogen. Methods : First, the theories of warm pathogen as developed by historical doctors were studied, and elements that seem to be related to the understanding of Onsasangsu were selected and studied to understand their theoretical characteristics. Furthermore, the paper studied what academic significance do these theories have on the development of the theory of warm pathogen. Results & Conclusions : Provided that the underlying assumption of Onsasangsu is that febrile diseases are caused through moutn and nose, the study showed that this understanding arose before the period of Qing Dynsasty from the need by many doctors to differentiate the pathogens of various diseases such as the disease of heat, febrile disease, and epidemic. The reason that these discussions could not have much impact on the study of febrile disease during the Qing Dynasty could be because they were not passed on down to the future generations, or because commonly held perspective was unable to accept criticisms.