• Title/Summary/Keyword: Space Mineral

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A Study on Relationship Between Basic Frictional Angle and Mineral Composition for Granite Sample (화강암 시험편의 광물조성과 기본마찰각의 상관성에 관한 연구)

  • Lee, Bong-Hyun;Lee, Seung-Joong;Choi, Sung-Oong
    • Tunnel and Underground Space
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    • v.24 no.1
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    • pp.32-45
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    • 2014
  • Basic frictional angle is a parameter that can estimate shear strength of rock, and is a design parameter employed in slope stability analysis. Basic frictional angle generates various results in accordance with mineral composition, apart from rock surface roughness itself. This paper describes the correlation of basic frictional angle and mineral composition. The basic frictional angle is measured with the aid of the modified tilt testing apparatus, and its reliability is improved by the statistical method. Also, mineral composition is identified through the photographic analysis on rock specimen, and verified through the thin section analysis.

Structural Geometry of a Regional-scale Overturned Fold in the Daecheong Island, Central-western Korean Peninsula (한반도 중서부 대청도에 발달하는 광역규모 과습곡의 구조기하학적 특징)

  • Jeong-Yeong Park;Deung-Lyong Cho;Seung Hwan Lee;Yujung Kwak;Seung-Ik Park
    • Economic and Environmental Geology
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    • v.57 no.1
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    • pp.41-50
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    • 2024
  • This study reports the structural geometry and folding mechanism of a regional-scale overturned fold in the Daecheong Island, central-western part of the Korean Peninsula. Based on low-hemisphere stereographic and down-plunge projections using data from a detailed field survey, we classify the regional-scale fold as an open overturned fold shallowly plunging toward NE. The asymmetric and symmetric parasitic folds in the limb and hinge zones indicate layer-parallel shortening prior to flexural-flow folding. Fold dating must be required to decipher the orogenic process causing the regional-scale overturned fold in the Daecheong Island.

3D gravity inversion with Euler deconvolution as a priori information (오일러 디컨벌루션을 사전정보로 이용한 3 차원 중력 역산)

  • Rim, Hyoung-Rae;Park, Yeong-Sue;Lim, Mu-Taek;Koo, Sung-Bon;Kwon, Byung-Doo
    • Geophysics and Geophysical Exploration
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    • v.10 no.1
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    • pp.44-49
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    • 2007
  • It is difficult to obtain high-resolution images by 3D gravity inversion, because the problem is extremely underdetermined - there are too many model parameters. In order to reduce the number of model parameters we propose a 3D gravity inversion scheme utilising Euler deconvolution as a priori information. The essential point of this scheme is the reduction of the nonuniqueness of solutions by restricting the inversion space with the help of Euler deconvolution. We carry out a systematic exploration of the growing body process, but only in the restricted space within a certain radius of the Euler solutions. We have tested our method with synthetic gravity data, and also applied it to a real dataset, to delineate underground cavities in a limestone area. We found that we obtained a more reasonable subsurface density image by means of this combination between the Euler solution and the inversion process.

Analysis of Biomass Energy Potential and Density in Korea (국내(國內) 바이오매스 에너지 잠재량(潛在量) 및 밀집도(密集度) 분석(分析))

  • Kook, Jin Woo;Shin, Ji Hoon;Yoo, Ho Seong;Lee, See-Hoon
    • Resources Recycling
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    • v.22 no.5
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    • pp.56-62
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    • 2013
  • The biomass resources is one of promising ways to solve energy exhaustion issues and global warming issues at the same time. To evaluate domestic biomass resources potential such as agricultural wastes, forestry wastes, livestock wastes and municipal solid wastes, statistics data from various organizations were collected and analyzed in this study. Also, space energy densities of each districts in Korea were calculated and analyzed. The results from the evaluation of biomass energy potential and space energy densities in Korea might be useful to estimate the availability of biomass energy conversion processes and to choice a appropriate process to convert domestic biomass into energy.

An Experimental Study on Measurement Method for Grain Bulk Modulus of Sandstone (사암의 입자 체적계수 측정 방법에 대한 실험적 연구)

  • Min-Jun Kim;Eui-Seob Park;Chan Park;Junhyung Choi
    • Tunnel and Underground Space
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    • v.33 no.2
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    • pp.71-82
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    • 2023
  • This study presents a direct measurement method for grain bulk modulus, which is important hydraulic-mechanical properties of rock, and conducts the experiment to investigate the grain bulk modulus of sandstone. In addition, the factors affecting the grain bulk modulus were investigated, comparing volumetric characteristics of rocks with different properties. As a result of the experiment, it was confirmed that the theoretically estimated bulk modulus is overestimated than the direct measured one. The possibility of the difference was analyzed, discussing the existence of non-connected pore space due to particle structure of the rock. Finally, the experimental results showed that the direct measurement suggested in this study can reliably predict the grain bulk modulus of sandstone.

Detection of an Impact Flash Candidate on the Moon with an Educational Telescope System

  • Kim, Eunsol;Kim, Yong Ha;Hong, Ik-Seon;Yu, Jaehyung;Lee, Eungseok;Kim, Kyoungja
    • Journal of Astronomy and Space Sciences
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    • v.32 no.2
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    • pp.121-125
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    • 2015
  • At the suggestion of the NASA Meteoroid Environment Office (NASA/MEO), which promotes lunar impact monitoring worldwide during NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission period (launched Sept. 2013), we set up a video observation system for lunar impact flashes using a 16-inch educational telescope at Chungnam National University. From Oct. 2013 through Apr. 2014, we recorded 80 hours of video observation of the unilluminated part of the crescent moon in the evening hours. We found a plausible candidate impact flash on Feb. 3, 2014 at selenographic longitude $2.1^{\circ}$ and latitude $25.4^{\circ}$. The flash lasted for 0.2 s and the light curve was asymmetric with a slow decrease after a peak brightness of $8.7{\pm}0.3mag$. Based on a star-like distribution of pixel brightness and asymmetric light curve, we conclude that the observed flash was due to a meteoroid impact on the lunar surface. Since unequivocal detection of an impact flash requires simultaneous observation from at least two sites, we strongly recommend that other institutes and universities in Korea set up similar inexpensive monitoring systems involving educational or amateur telescopes, and that they collaborate in the near future.

Geotechnical Exploration Technologies for Space Planet Mineral Resources Exploration (우주 행성 광물 자원 탐사를 위한 지반 탐사 기술)

  • Ryu, Geun-U;Ryu, Byung-Hyun
    • Journal of the Korean Geotechnical Society
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    • v.38 no.9
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    • pp.19-33
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    • 2022
  • Planarity geotechnical exploration missions were actively performed during the 1970s and there was a period of decline from the 1 990s to the 2000s because of budget. However, exploring space resources is essential to prepare for the depletion of Earth's resources in the future and explore resources abundant in space but scarce on Earth, such as rare earth and helium-3. Additionally, the development of space technology has become the driving force of future industry development. The competition among developed countries for exoplanet exploration has recently accelerated for the exploration and utilization of space resources. For these missions and resource exploration/mining, geotechnical exploration is required. There have been several missions to explore exoplanet ground, including the Moon, Mars, and asteroids. There are Apollo, LUNA, and Chang'E missions for exploration of the Moon. The Mars missions included Viking, Spirit/Opportunity, Phoenix, and Perseverance missions, and the asteroid missions included the Hayabusa missions. In this study, space planetary mineral resource exploration technologies are explained, and the future technological tasks of Korea are described.

Heavy Metal Contamination, Mineral Composition and Spectral Characteristics of Reddish Brown Precipitation Occurring at Osip Stream Drainage, Gangwon-do (강원도 오십천 수계에서 발생하는 적갈색침전물의 중금속 오염, 광물조성 및 분광학적 특성)

  • Lim, Jeong Hwa;Yu, Jaehyung;Bae, Sungji;Koh, Sang-Mo;Park, Gyesoon
    • Journal of the Mineralogical Society of Korea
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    • v.31 no.2
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    • pp.75-86
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    • 2018
  • This study analyzed precipitation environment, heavy metal concentration, mineral composition, and spectral characteristics associated with heavy metal concentration and mineral composition for the reddish brown precipitates occurred in the drainage of Dogye mining station. The pH of the reddish brown precipitates ranges from 7.59 to 7.94 resulting neutral. XRF analysis reveals that the precipitates has high Fe concentration, and contaminated with Ni, Cu, and Zn. Dolomite, calcite, goethite, magnetite, kaolinite, pyrophyllite, quartz and aluminum isopropoxide were identified based on XRD analysis. As a result of spectral analysis associated with heavy metal contamination, visible reflectance increases and infrared reflectance decreases with a increase in heavy metal concentration. The spectral characteristics of the reddish brown precipitates is turned out to be manifested by goethite, magnetite, kaolinite, pyrophyllite and aluminum isopropoxide.

Development and Verification of OGSFLAC Simulator for Hydromechanical Coupled Analysis: Single-phase Fluid Flow Analysis (수리-역학적 복합거동 해석을 위한 OGSFLAC 시뮬레이터 개발 및 검증: 단상 유체 거동 해석)

  • Park, Chan-Hee;Kim, Taehyun;Park, Eui-Seob;Jung, Yong-Bok;Bang, Eun-Seok
    • Tunnel and Underground Space
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    • v.29 no.6
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    • pp.468-479
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    • 2019
  • It is essential to comprehend coupled hydro-mechanical behavior to utilize subsurface for the recent demand for underground space usage. In this study, we developed a new simulator for numerical simulation as a tool for researching to consider the various domestic field and subsurface conditions. To develop the new module, we combined OpenGeoSys, one of the scientific software package that handles fluid mechanics (H), thermodynamics (T), and rock and soil mechanics (M) in the subsurface with FLAC3D, one of the commercial software for geotechnical engineering problems reinforced. In this simulator development, we design OpenGeoSys as a master and FLAC3D as a slave via a file-based sequential coupling. We have chosen Terzaghi's consolidation problem related to single-phase fluid flow at a saturated condition as a benchmark model to verify the proposed module. The comparative results between the analytical solution and numerical analysis showed a good agreement.

Development of Multi-Components Model of Cement Hydration

  • Wang, Xiao-Yong;Lee, Han-Seung;Gyeong, Je-Un;Park, Gi-Bong
    • Proceedings of the Korean Ceranic Society Conference
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    • 2007.07a
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    • pp.129-137
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    • 2007
  • This paper presents a numerical model which can predict degree of hydration of cement mineral component, such as $C_{3}S$, $C_{2}S$, $C_{3}A$, $C_{4}AF$ and microstructure of hydrating cement as a function of water to cement ratio, cement particle size distribution, cement mineral components and temperature. In this model cement particles are parked randomly in cell space and hydration process is described using a multi-component integrated kinetic model. The simulation result of degree of hydration of cement mineral component agrees well with experiment result. The content of cement hydration product, such as CSH and CH can be obtained as an accompanied result during hydration process. By introducing of equal-area projection method, water withdrawl mechanism and contact area among cement particles can be considered in detail. By using proposed method, pore size distribution of hydrating cement is predicted.

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