• 콘크리트학회논문집
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• 제14권3호
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• pp.440-448
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• 2002

산업의 발달과 더불어 폐유리의 발생량은 점차 증가되고 있다. 콘크리트에 폐유리를 사용할 경우 알칼리 실리카 반응(ASR)에 의한 팽창으로 콘크리트에 균열이 발생하여 성능저하를 일으킬 수 있다. 본 연구에서는 폐유리의 색깔(갈색, 녹색), 입도 및 폐유리로 인해 발생되는 ASR팽창을 저감시키기 위해 산업부산물의 종류(플라이애시, 고로슬래그 미분말)와 혼입율에 따른 ASR팽창과 강도특성을 분석하였다. 또한, 포졸란 재료로서 폐유리 분말의 사용가능성을 분석하였다. 연구결과, 폐유리의 색깔에 관계없이 폐유리의 퍼시멈 입도는 2.5~l.2mm로 나타났으며, 폐유리의 입도가 2.5~l.2 mm보다 작을수록 팽창은 점차 감소하는 것으로 나타났다. 또한, 폐유리에 산업부산물의 혼입은 ASR로 인한 팽창과 강도저하를 억제시키는데 효과적이며, 0.075 mm미만의 폐유리 분말이 포졸란 재료로서 적용이 가능한 것으로 나타났다.

• 한국축산식품학회지
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• 제44권2호
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• pp.483-497
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• 2024

This study investigated the effects of ultra-ground seaweed powders (USP) on the physicochemical properties (proximate composition, mineral contents, pH, color, shear force, sensory evaluation, electronic nose, and electronic tongue) of restructured black goat jerky. Restructured black goat jerky was prepared using three different treatments, i.e., 3% (w/w) each of ultra-ground sea tangle (ST; Undaria pinnatifida), sea mustard (SM; Saccharina japonica), and sea string (SS; Gracilaria verrucosa) powders. Moisture and ash contents were significantly higher in the USP-treated group than in the control (p<0.05). Potassium, calcium, and zinc contents were significantly higher in the SM than in the other USP-treated groups (p<0.05). In contrast, pH values were significantly higher in the ST and SM than in the control and SS (p<0.05). CIE L^*, CIE a^*, CIE b^*, and shear force were significantly lower in the USP-treated groups than in the control (p<0.05). Sensory evaluation revealed no significant difference in taste, texture, seaweed-like odor, and goaty flavor (p<0.05). Principal component analysis (PCA) and peak graph analysis of the electronic nose showed that the SS differed the most from the control compared with the other USP-treated groups, owing to the seaweed odor of ultra-ground SS powder. The PCA and ranking analysis of the electronic tongue showed that the umami taste of the SM was higher than that of the control and other USP-treated groups. Therefore, the potassium, calcium, zinc contents, and umami taste of reconstituted black goat jerky were significantly higher in the SM than in the control and other USP-treated groups.

• 접착 및 계면
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• 제13권3호
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• pp.121-130
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• 2012

본 연구에서는 대나무섬유의 분쇄 유 무에 따라 섬유함량이 각각 30, 40, 50 wt%인 대나무/PLA 펠렛을 압출공정으로 제조하고 사출공정을 통해 대나무/PLA 바이오복합재료를 성형하여 그들의 기계적, 열적, 충격 특성과 수분흡수성을 조사하였다. 대나무/PLA 바이오복합재료의 굴곡탄성률, 인장탄성률, 저장탄성률 및 충격강도는 neat PLA에 비하여 두드러지게 증가되었다. 특히 탄성률은 분쇄된 대나무섬유의 도입에 의하여 더욱 증가하였다. 또한 분쇄한 대나무섬유의 사용이 바이오복합재료의 장시간 동안 측정한 수분에 대한 저항성 증가에 효과적이었다. 대나무섬유의 사용이 neat PLA의 열변형온도를 약 16% 향상시키는 효과를 나타내었으나, 분쇄된 대나무섬유의 사용에 의한 증가는 미미하였다. 분쇄된 대나무섬유의 사용은 바이오복합재료의 인장강도와 충격강도에는 크게 영향을 주지 않았다.

• 터널과지하공간
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• 제18권1호
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• pp.69-79
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• 2008

독도는 약 $300{\sim}220$만 년 전에 형성된 해양섬 기원의 화산체로서 동도와 서도로 구성되어 있다. 비록 규모는 작지만 동해의 형성 및 진화와 연관된 지질과학적 중요성 외에 자원적, 생태적, 영토적 가치, 그리고 일본과의 독도 영유권 문제와 관련한 국민적 관심 등 경제 사회 과학 기술적 측면에서 무한한 잠재적 가치와 의미를 갖고 있는 지역이다. 최근 동도 육상부에서 급속하게 진행되고 있는 풍화 및 침식작용으로 인한 각종 균열로 인하여 독도 지반의 안정성 평가의 필요성이 제기되었다. 본 논문은 독도의 지반안정성 분석을 위한 사전조사단계로서 독도의 지질과 층서, 지반불안정을 발생시키는 요인에 대하여 알아보고 육안관찰에 의해 위험요소로 판단된 지역에서 수행되었던 독도 암석의 역학적 특성을 분석하였다. 독도의 암석은 주로 응회암, 조면암, 조면안산암으로 구성되어 있으며, 전체적으로 풍화와 침식에 의해 국내 암석의 역학적 물성수치에 비해 상대적으로 낮았다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.266-292
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• 2007

Round Robin Test (RRT) on ground response analyses was conducted for three sites in Korea based on several site investigation data, which include borehole logs with the N values from standard penetration test (SPT) for all three sites and additionally cone tip resistance profiles for two sites. Three input earthquake motions together with the site investigation data were provided for the RRT. A total of 12 teams participating in this RRT presented the results of ground response analyses using equivalent-linear and/or nonlinear method. Each team determined input geotechnical properties by using empirical relationships and literatures based on own judgment, with the exception of the input motions. Herein, the characteristics of input motions were compared in terms of the frequency and period, and the selection of the depth to bedrock, on which the motions is impinged, was discussed considering geologic conditions in Korea. Furthermore, a variety of geotechnical properties such as shear wave velocity profiles and soil nonlinear curves were investigated with the input properties used in this RRT.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.325-328
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• 2005

To estimate presumptive local ground subsidence area near Abandoned Under ground Coal Mine(AUCM) at Samcheok city in Korea, the geological properties of existing ground subsidence area and the geophysical prospecting data were analyzed using GIS. The electrical resistivity survey and seismic reflection survey database were constructed from investigation reports and factors which are related with ground subsidence such as geological map, topological map, land use map, lineament map, groundwater level, RMR (Rock Mass Rating), mining tunnel map and slope database were constructed also to make a comparative study of each parameters. As a result of the spatial analysis of existing ground subsidence area, 9 major factors causing ground subsidence were extracted and a connection between the structure of underground and the ground subsidence was determined from the analysis of geophysical prospecting data. The estimation of presumptive ground subsidence area was performed using the correlation between the result from neural network analysis of 9 factors and the scrutiny of geophysical prospecting data.

• Geomechanics and Engineering
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• 제33권5호
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• pp.439-451
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• 2023

The construction of shield tunnelling in urban sites is facing serious risks from complex and changeable underground conditions. Construction problems in the sand-clay mixed ground have been more reported in recent decades for its poor control of soil loss in tunnel face, ground settlement and supporting pressure. Since the limitations of observation methods, the conventional physical modelling experiments normally simplify the tunnelling to a plane strain situation whose results are not reliable in mixed ground cases which exhibit more complicated responses. We propose a new method for the study of the mixed ground tunnel through which mixed lays are simulated with transparent soil surrogates exhibiting different mechanical properties. An experimental framework for the transparent soil modelling of the mixed ground tunnel was established incorporated with the self-developed digital image correlation system (PhotoInfor). To understand better the response of face stability, ground deformation, settlement and supporting phenomenon to tunnelling excavation in the sand-clay mixed ground, a series of case studies were carried out comparing the results from cases subjected to different buried depths and mixed phenomenon. The results indicate that the deformation mode, settlement and supporting phenomenon vary with the mixed phenomenon and buried depth. Moreover, a stratigraphic effect exists that the ground movement around mixed face reveals a notable difference.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.826-830
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• 2007

The effects of the statistical properties of the Coulomb friction coefficients on the dynamic responses of a galloping quadruped robot are investigated in this paper. In general, the Coulomb friction coefficients are assumed to be deterministic for a controller design to achieve required motion characteristics. However, the friction coefficients between the ground and the robot legs are not constant in reality. Therefore, statistical characteristics of the friction coefficients need to be considered for a multi-body modeling of the robot galloping on the ground. The effects of the statistical properties on the dynamic responses of the quadruped robots are investigated.

• 터널과지하공간
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• 제4권1호
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• pp.31-37
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• 1994

The effects of blasting and ground vibratons on curing concrete have not been well studied. As a results unrealistic and costly ground vibration constraints have been placed on blasting and piling when it occurs in the vicinity of curing concrete. To study the effects of ground vibrations, a shaking table was made to produce peak particle velocities in the nearly same frequency range as found in construction blasting. Concrete blocks of 33.3X27.7X16.2cm were molded and placed on the shaking table. Different sets of concrete blocks were subjected to peak vibrations of 0.25, 0.5, 1.0, 5.0 and 10cm/sec. The impulses were applied at two hour intervals for thirty seconds. Along with unvibrated concrete blocks, the vibrated concrete samples with 60.3mm in diameters were measured for elastic moduli, sonic velocity, tensile and uniaxial compressive strength. Test results showed that the vibrations in curing concrete generally have effects on the uniaxial compressive strength or physical properties of the concrete.

• 한국재난정보학회 논문집
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• 제6권2호
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• pp.45-65
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• 2010

There has been tighten up the need of seismic retrofit about 31 public facilites since published "Korean Earthquake Damage Prevention Law". Therefore, seismic studies have been developed and enforced the studies. Measuring dynamic stiffness of subsurface materials influence on seismic performance evaluation to build up seismic retrofit. The soil dynamic properties for seismic performance evaluation are N-value from using SPT(standard penetration test), dynamic shear elastic modulus and dynamic deformation modulus using laboratory tests. The most unscientific element in ground dynamic properties involved uncertainties is obviously N-value using SPT. This study shows that effect of N-value included natural and artificial uncertainties to seismic performance evaluation of ground structures is not only approached probabilistic analysis using FOSM method and tornado diagram, but also review how to spread effect of seismic performance evaluation of ground structures.