• 제목/요약/키워드: Stone Characteristics

검색결과 709건 처리시간 0.026초

혐기성 고정상 생물반응기에서 담체의 종류에 따른 Biogas 생성 및 미생물 부착 특성에 관한 연구 (The Characteristics of Attached Biomass and Biogas Production in an Anaerobic Packed Bed Bioreactor with Several Carriers)

  • 안재동;강동수;장인용
    • 한국환경보건학회지
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    • 제18권2호
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    • pp.75-81
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    • 1992
  • An experimental investigation has been carried out to evaluate the characteristics in wastewater treatment using an anaerobic packed bed bioreactor with ceramics, rubber sponge, soft stone A, and soft stone B as carrier. The results of the work have shown that soft stone A as a carrier was superior to other carriers in methane production, then the content of methane for soft stone A was about 70%. First of all, soft stone A had higher efficiency of the COD removal than the others in response of passing the operation, as well as it had a low volatile acid in reactor. In addition, the slope of methane production with respect to the removal of COD ($m^{3}CH_{4}$/kgCOD) was 0.58 for soft stone A. In biomass hold-up equation for each carriers, the equation of soft stone A was m$_{p}$=714 ($C_{o}/0.41+C_{o}$) and it was the largest in this experimented carriers. Based upon the results obtained, it is suggested that the major effective carrier in wastewater treatments within the packed bed bioreactor used in this experimental work by soft stone A.

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제주 올래와 올랫담의 유형적 특성에 관한 연구 - 무근성 지역을 중심으로 - (A Study on Characteristics of Olle and Olle-Dam in Old Settlements of Jeju - Focused on a "Mu-geun-sung" area -)

  • 이용규;이승택;김정곤
    • 한국농촌건축학회논문집
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    • 제19권3호
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    • pp.9-16
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    • 2017
  • The study aims to find regional characteristics of Olle and Olle-Dam the old town of Jeju city, "Mu-geun-sung," through researches of the status of the spatial structure in the area. The research was mainly conducted through literature survey and field survey. Literature survey was conducted for the typification of alleys and stone walls. Field surveys were conducted to reveal the location, length, and materials of the stone walls on alleys. As a result, this study can grasp the spatial characteristics of the alleys and the typological characteristics of the stone walls in the old urban areas of Jeju City. The unit alley located in the old city area of Jeju was severely damaged. Also, the stone walls could reveal that there are few areas where the original shape is preserved. The management of the community has not been properly carried out in the use of alleys. In addition, there is concern about the damage caused by securing a road in the future. On the other hand, many of the damaged stone walls had basically the original shape. There were many stone walls that retained their original shape in the old alley. For this reason, there is a high possibility that the alleys and stone walls located in the old urban areas of Jeju are utilized as assets of the area. Based on the results of the above study, community recovery using old alleys of Jeju is required.

숭례문 사례를 통한 육축 문화재의 구조특성 연구 (A Study on Structural Characteristics of Stone Masonry Wall Structure)

  • 이성민;이기학;최희수;박주경;최취경
    • 한국공간구조학회논문집
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    • 제11권4호
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    • pp.61-69
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    • 2011
  • 우리나라의 석조문화재을 모델링할 때 불연속면을 갖는 구조재의 강성을 어떻게 규명하느냐가 매우 중요하지만 원형보존을 해야 하는 문화재의 특성상 이를 파악하기란 매우 곤란하다. 이를 위해 본 연구에서는 비파괴조사를 이용하여 고유진동수를 측정한 후, 시행착오법을 이용하여 측정된 고유진동수와 컴퓨터 모델링 해석을 통해 고유진동수를 비교함으로써 불연속면의 강성, 구조재의 탄성계수 등 숭례문 육축 구조를 이루는 재료의 구조적 물성을 추정하였다. 이를 통해 육축 문화재에 대한 컴퓨터 모델링 기법을 제시하고 육축구조물의 안전성에 영향을 미치는 요인을 분석하였다. 연구결과 적심석의 강성이 육축구조물의 안전성에 가장 큰 영향을 미지는 젓으로 분석되었다.

대입경 혼합물의 역학적 특성 평가 (Evaluation of the Mechanical Characteristics of the Large Stone Asphalt Mixtures)

  • 박태순;김주원;김용주
    • 한국도로학회논문집
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    • 제2권2호
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    • pp.129-138
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    • 2000
  • 본 연구는 대입경 혼합물의 배합설계와 소성변형 및 균열특성에 관련된 역학적 특성에 관한 연구결과이다. 대입경 혼합물은 1989년 미국 아스팔트기술쎈타의 Kandhal에 의해서 연구되었으며, 일본 및 아랍의 여러 국가에서 포장건설에 사용하고 있다. 이들의 경험과 연구결과에 의하면 대입경 혼합물을 구성하고 있는 골재의 구성은 결합력이 견고하고 바인더가 고온에서 영향을 받지 않아 소성변형에 큰 저항성을 보이는 것으로 알려져 있으나, 실제로 증명할 수 있는 역학적인 시험을 수행한 자료는 없는 실정이다. 본 연구에서는 크리프시험, 회복탄성계수시험, 휠 트래킹시험 및 라벨링 시험을 실시하여 대입경 혼합물의 특성을 분석하였으며 시험 결과를 일반 혼합물 및 개질아스팔트 혼합물과 비교한 결과 대입경 혼합물의 소성변형에 대한 저항성은 매우 우수한 것으로 나타났다.

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고강도 지오그리드로 보강된 Stone Column 공법의 침하감소효과 (Settlement Reduction Effect of the Geogrid Reinforced Stone Column System)

  • 박시삼;조성한;유충식;이대영
    • 한국지반신소재학회논문집
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    • 제5권1호
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    • pp.15-23
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    • 2006
  • 모래다짐말뚝 및 쇄석말뚝 공법의 경우, 연약지반의 보강, 극한지지력의 증대 및 기초지반의 압밀을 가속화시키기 위한 목적으로 지난 수십 년간 폭넓게 적용되고 있다. 쇄석말뚝공법은 비교적 강성이 크고 압축성이 작은 쇄석 등을 이용하여 다짐말뚝을 형성, 연약지반을 개량하는 공법이지만 횡방향 구속압력이 충분하게 발휘되지 않는 지반에서는 팽창파괴(bulging failure)에 대한 저항이 없어 적용이 불가능하게 된다. 따라서 본 연구에서는 쇄석말뚝의 활용도를 높이기 위해 팽창파괴 및 전단파괴 등을 방지하여 침하량을 상당부분 억제시킬 수 있는 고강도 지오그리드 보강 쇄석말뚝공법을 개발하였다. 본 공법 개발을 위해 삼축압축시험을 통하여 치환율 및 구속압력에 따른 일반적인 쇄석말뚝의 거동특성을 우선 살펴보았다. 아울러 유한요소 해석을 통한 3차원 수치해석을 시행하여 지오그리드의 종류 및 지오그리드 보강심도변화에 따른 지오그리드 보강 쇄석말뚝공법의 거동특성 및 침하저감효과를 평가함으로써 지오그리드 보강 쇄석말뚝의 적용성을 평가해 보았다.

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적층 구조물의 압축응력과 동적특성 (Dynamic Characteristics and Compressive Stress of Multi-Layered Structure)

  • 손호웅;이성민
    • 지구물리
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    • 제9권1호
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    • pp.63-71
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    • 2006
  • When surveying the cultural heritages especially in the case of stone structures, preserving their originalstate is of primary importance. For the effective assessment of survey results of stone structure, thedynamic characteristics of that system should be considered. Dynamic characteristics of stone masonry structures depend on several factors such as coefficients of friction, contact conditions, and number of layers of bonding stones. These factors can be estimated by using the dynamic analysis results. This paper describes a method for natural frequency determination of traditional stone arch bridge subjected to compressive force. For this purpose, multi-layered granite brick models of for arch bridge were made and fundamental frequencies corresponding increasing axial forces were measured.

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석벽돌 적층모형의 압축응력과 동적특성 (Dynamic Characteristics and Compressive Stress of Multi-Layered Stone Masonry Model)

  • 이성민;손호웅;이수곤
    • 지구물리
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    • 제7권1호
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    • pp.31-40
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    • 2004
  • 문화재 특히 석조구조물을 조사 할 경우에 원형 및 상태를 보존하는 것은 매우 중요하다. 석조구조물에 대한 조사 결과의 효율적인 평가를 위해서는 동적특성을 고려하여야만 한다. 석조구조물의 동적특성을 마찰 접촉조선 석층수 등의 요인에 의한다 이러한 요소는 동적해석결과로부터 추정할 수 있다. 본 연구는 압축력을 받고있는 전통적인 홍예교의 고유 진동수 결정 방법에 관한 연구결과이다.

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외국인 묘지 기념물의 디테일 특성 - 양화진 외국인 묘지공원을 사례로 - (The Characteristics of Monuments in a Cemetery - ln the Case of the Seoul Foreigners' Cemetery Park at Yanghwajin -)

  • 이상석
    • 한국조경학회지
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    • 제31권6호
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    • pp.28-40
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    • 2004
  • The purpose of this study is to identify the characteristics of monuments in the Seoul Foreigners′ cemetery at Yanghwajin, a place where many prominent Christian missionaries and other Christians have been buried near Choltusan. In considering the characteristics of gravestone details, the researcher has divided the details into 4 analysis categories: forms, symbols, epitaphs, and materials. For this research, 281 monuments were selected including 68 of missionaries, 26 of U. S. Army Soldiers, and 13 of teachers. The analysis revealed that there were 26 types of monuments. This includes simple and standardized types like the tablet, headstone, marker, and monolith. These were used more often than other shaped types such as the Cross, obelisk, sculpture, etc. Standardized types made in Korea have been preferred after the 1950s even though the beauty of the gravestones has been degraded. Symbolical decorations related to religious, social, professional or military emblems were also introduced to strengthen their symbolical objectives. Among them, fie Cross was the most predominant Christian symbol and emblem. The families wanted to inscribe epitaphs, the greater part of which originated from the Bible, poems, idioms related to tribute, rest, supplications to deity, love, achievement, to express human sentiment and religious faith. When using materials for making monuments, monument makers have mostly used stone because of its durability. Until the 1950s, various stones had been used to make monuments, for most marble and granite were brought from foreign countries. These were very different from the Korean white marble stone used for many monuments. After the 1950s, the source of stone has been limited to Korean stone, for Korean could make stone monuments that foreigners were agreeable. Especially, a black marble stone called "O-Suk" which means black stone, has been used as a main material. The study identified the following characteristics of monument details in the Seoul foreigners′ cemetery at Yanghwajin. First, Christianity has been applied as the main concept, while symbolizing the homogeneity of religious, family, social, professional or military groups by having the symbolic form, symbol, and epitaph in common. Second, monuments made after the 1950s have been standardized into unattractive and monotonous forms by the limited materials, and so the beauty of the monuments has been degraded.

DYNAMIC CHARACTERISTICS OF ANCIENT STONE ARCH BRIDGES

  • SungMinLee;HoWoongShon
    • 지구물리
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    • 제6권3호
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    • pp.125-130
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    • 2003
  • The aim of this paper is to investigate the dynamic characteristics of ancient stone bridges in Korea and to find the factors influencing their natural frequencies. For this end, on-site free vibration tests were performed for 18 stone arch bridges and one ancient ice storage composed of 4 arches. Test results revealed that the vertical fundamental frequencies were in the range of 10Hz to 45Hz. The damping ratios estimated from the records of free vibration tests showed a wide variety of values, that is, from 0.02 to 0.134. It has been known that the natural frequencies of stone arch bridges are mainly governed by their arch spans. Test results reveal that the presence of spandrel walls and the use of mortar for joints are also important factors influencing the natural frequencies of stone arch bridges.

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A Study on the Material Characteristics of Stone Tools Excavated from the Remain Point of Paleolithic Age in Osong Site, Cheongju

  • Kim, Jae Hwan;Han, Min Su
    • 보존과학회지
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    • 제35권1호
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    • pp.41-49
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    • 2019
  • This study analyzes the material characteristics of stone tools of the Paleolithic period excavated from the Osong site, located at the project site for the creation of the Osong 2nd Life Science Complex, and estimates the provenance of the stone materials. Because the stones had been buried for a long time, their surfaces had become heavily weathered yellow or yellowish-brown, and the magnetic susceptibility values varied from 0 to 15(${\times}10^{-3}SI$). The excavated stone tools were rocks with various magnetic susceptibility values that could not be specified. Five stone tools subjected to destructive analysis were divided into two groups, one with a value of 1-3(${\times}10^{-3}SI$) and the other with a value of 5-9(${\times}10^{-3}SI$), both based on visible characteristics. The results of the thin-section analysis showed that most of the stone tools were basaltic rocks comprising plagioclase, quartz, and pyroxene, and some had iron content as high as 20 wt.%. These findings and the present geological map suggest that the stone tools were not made from the surrounding rocks because there are no areas containing basaltic rocks surrounding Bongsan-ri in Osong-eup. Andesite and tuff are distributed along with basaltic rocks in the Doan-myeon area in Jeongpyeong-gun, Chungcheongbuk-do Province, but the distance from the excavation site is too far. To determine whether this region is actually related to the provenance of the raw rock, it is necessary to conduct additional field surveys and comprehensive and precise analyses.