• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.88-93
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• 2019

This study concerns the distributions of flow in an air conditioning duct used for a marine and oil drilling ship. From the results of carrying out flow analysis and structural analysis of a ventilation duct applied to a marine structure, the following conclusion could be gained. The pressure tended to increase as the flow velocity at the inlet increased and the pressure at the inlet increased. It was recognized that the pressure decreased due to the influence of a corrugated tube when it entered and exited from the duct. As a result of structural analysis, a higher train was generated at the corrugated tube compared with the duct. In addition, in the case of the internal pressure of 0.7MPa, which was the designed load, it was found that there was almost no influence as it was within 0.1mm.

• 한국해양학회지
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• v.30 no.4
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• pp.332-340
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• 1995

To study stratigraphy of tidal basin deposits, related unconformity and source of late Holocene tidal sediments in Namyang Bay, west coast of Korea, total 8 vibracore sediments have been analyzed. The uppermost stratigraphic sequence of the late Holocene Namyang intertidal deposit overlies three different stratigraphic sequences (1) oxidized reddish brown muddy deposit (Yongduri Member), (2) oxidized yellow deposit (Kanweoldo Formation) and (3) the pre-Cambrian gneiss complex unconformably. Accordingly, three unconformities between those different sequences are recognized. The Namyang tidal deposits (late Holocene) with several meter thickness are mostly coarsening upward sequence suggesting transgressive phase during a continuous rise of sea level. The tidal deposit vibracored down to 4.5 m in depth contains clastic glauconite sands (2% in average) from 2.5 m to the vibracore bottom. These glauconite sands are considered to be transported to the site of Namyang Bay tidal sedimentation from offshore continental shelf of the Yellow Sea along the course of late Holocene sea-level rise.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.73-81
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• 2005

Mineralogical and chemical examinations were performed on chlorite-smectite mixed layer minerals that occur in the sandstones from a petroleum exploration well in the southern part of the Ulleung Basin. X-ray diffraction and chemical analyses show that the chlorite-smectite mixed layer mineral is tosudite, a 1 : 1 R1 ordered interstratification of chlorite and smectite with an overall dioctahedral character. This mineral is almost the same as the tosudite reported from hydrothermally-altered regions, which is rich in Li. This fact indicates that the tosudite area may be affected by hydrothermal events, because the studied well is located in the tectonically-deformed area, in which lots of trust faults and folds are present. In these respects, the formation of tosudite is probably due to the variable effect of hydrothermal fluids from the deeper part of the area.

• Information and Communications Magazine
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• v.30 no.10
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• pp.38-45
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• 2013

2009년 초반 중국은 물량중심으로 조선분야 수주잔량 부분에서 한국을 추월하였으나, 현재 한국은 조선강국으로서의 위치를 고수하기 위해 IT조선 융합기술 개발을 통하여 디지털선박과 해양플랜트 등 고부가가치 선박 제품을 제조하고 있으며, 이러한 선박 제조 과정에서 에너지 및 인력 절감을 통해 고효율화, 안전성 제고 등 신뢰도 향상 또한 추진하고 있다. 최근 국내에 수주되고 있는 LNG선, 호화여객선, 석유시추선 등의 쉐이빙선과 같은 고부가가치 선박의 경우 국산화율이 60%가 채 되지 않는 현 상황에서 선박 관련 IT 기술 확보는 선박 건조 국산화 비율을 높이고 조선산업 수주 경쟁력을 높이는 중요한 관건이 될 것으로 예상한다. 본고에서는 세계 1위를 지키고 있는 조선산업의 질적성장을 위한 IT+조선 기술현황과 전망에 대해 기술한다.

• The Journal of Engineering Geology
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• v.26 no.3
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• pp.339-352
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• 2016

The best way of investigating the physical and mechanical properties of subsurface materials is the combined interpretation of data from borehole geophysical surveys and geotechnical experiments with rock samples. In this study two surface seismic surveys with refraction and surface-wave method are alternatively conducted for downhole seismic surveys in test site for geological field trip in Jeungpyung, Chungbuk. P- and S-wave velocity structures are delineated by refraction and MASW (multichannel analysis of shear waves) methods, respectively. Possion's ratio section, reconstructed from P- and S-wave velocities, is correlated to the outcrop geological features consisting of reddish sedimentary rock, gray volcanic rock, and joints/fractures. In addition, rock samples representative for reddish sedimentary and gray volcanic features are geotechnically analyzed to provide physical, mechanical properties, and elastic modulus. Dynamic elastic moduli estimated from geophysical data is found to be higher than the one from geotechnical data. Reddish sedimentary rock characterized with low porosity and moisture content corresponds to the zone of low electrical resistivities and their small variations in the resistivity sections between the rainy and dry days. This trend suggests that the weathered gray volcanic rock and the nearby fractures with higher low porosity and moisture content are interpreted to be good carrier especially in rainy season.

• Economic and Environmental Geology
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• v.48 no.2
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• pp.115-130
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• 2015

Extended elastic impedance (EEI) is an extension of elastic impedance (EI) which is a generalization of acoustic impedance (AI) for nonzero angles of incidence and can be tuned to be proportional to reservoir properties. In this study, we evaluated EEI inversion by estimating the P-($V_p$) and S-wave velocities ($V_s$), P-wave to S-wave velocity ratio ($V_p/V_s$), and Poisson's ratio of the Second Wall Creek Sand of the Teapot Dome field, Wyoming, USA. We also applied the EEI inversion technique to estimate porosity, gamma-ray values, and density of the Second Wall Creek Sand. Data used in the study include 3-D pre-stack seismic data from the southern part of the field and four wells, selected from a large well database. The $V_s$ logs at the wells were constructed from the $V_p$ logs using the empirical relationships. The percent prediction errors for the four velocity properties are less than about 5% except for Poisson's ratio at one well, supporting that the EEI inversion can be used in the prediction of rock properties. However, the results from the EEI inversion analysis of porosity, gamma-ray values, and density at the wells were unsatisfactory and thus these properties, which are not directly computed from velocities, may not be suitable for EEI inversion.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.489-500
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• 2017

It is not rare that pseudotachylite, dark colored rock with glassy texture, is recognizable in deep core samples drilled up to 900 m from the surface. Pseudotachylite with widths varying few to 20 cm is sharply contacted or interlayered with the host rocks composed of Jurassic granite and Precambrian amphibolite gneiss, showing moderately ductile deformation or slight folding. Pseudotachylite occurring at varying depths in the deep drill core are slightly different in texture and thickness. There is evidence of fault gouge at shallower depths, although brittle deformation is pervasive in most drill cores and pseudotachylite is identified at random depth intervals. Under scanning electron microscope (SEM), it is evident that the surface of pseudotachylite is characterized by a smooth, glassy matrix even at micrometer scale and there is little residual fragments in the glass matrix except microcrystals of quartz with embayed shape. Such textural evidence strongly supports the idea that the pseudotachylite was generated through the friction melting related to strong seismic events. Based on X-ray diffraction (XRD) quantitative analysis, it consists of primary minerals such as quartz, feldspars, biotite, amphibole and secondary minerals including clay minerals, calcite and glassy materials. Such mineralogical features of fractured materials including pseudotachylite indicate that the fractured zone might form at low temperatures possibly below $300^{\circ}C$, which implies that the seismic activity related to the formation of pseudotachylite took place at shallow depths, possibly at most 10 km. Identification and characterization of pseudotachylite provide insight into a better understanding of the paleoseismic activity of deep grounds and fundamental information on the stability of candidate disposal sites for high-level radioactive waste.

• The Journal of Engineering Geology
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• v.5 no.1
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• pp.1-20
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• 1995

A train overturn accident occurred on March 1993 in the Gupo area, northern part of Pusan, unfortunately had taken a heavy toll of lives and caused a great loss of property as well. The reasons for the subsidence of the basement under the railroads, which presumed to be the main cause of the accident, have been investigated from many different angles, including conventional geotechnical investigation methods. The deduced nuin reasons of the subsidence were: 1. blasting for tunnel excavation (NATM) at about 39 meter under the railroads, and 2. unexpected change of bedrock conditions along the direction of tunnel. But this accident was derived nrranlv from the lack of geological and geotechnical information under railroad area because it was impossible to drill beneath the railroads. This paper introduces a new geophysical survey techniqueseisrnic geotomography, and shows some results of the method applying to investigate the underground structure of the accident area. This method not only overcomes the unfavourable environment which many conventional investigation methods cannot face, but produces an image of underground structure with high resolution. Furthermore, the outputs from geotomogaphic analysis could provide very valuable in-situ basic parameters (like seismic velocities, elastic moduli, etc.) which is essential to the design and construction.

• The Journal of Engineering Geology
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• v.18 no.2
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• pp.137-144
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• 2008

The stand-off errors due to the different separations between the sonde and the borehole wall were measured and analyzed in 4 physical borehole models located in Kangwon National University having different densities with cylindrical and half cylindrical PVC and/or acrylic casings. The analysis of the stand-off error data based on the "spine and ribs" technique suggests a well defined rib line for each model irrespectively of the types and thicknesses of the casing, and that the gradients of the ribs are proportional to the densities of the models. By using these characteristics successful density correction could be made for the plastic casings in NX sized boreholes.

• Journal of the Korean Geotechnical Society
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• v.15 no.4
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• pp.185-205
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• 1999

Hydraulic fracturing tests were performed in two inclined boreholes for the design of underground oil storages in Korea. Extensions of their application limits were expected through a precise comparison between the interpretation techniques for the vertical and the inclined boreholes. Especially, it was verified that the magnitude of in-situ stress can be varied even in the same rock mass with a variety of geographic/geotechnical characteristics. It was also demonstrated that its orientation can be changed even in the same borehole with the existence of explicit discontinuities.