• 방사선산업학회지
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• 제4권4호
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• pp.391-395
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• 2010

The characteristics for pollutant transport in tidal influenced area was investigated using tidal wave hydraulic scale model. Hydraulic scale model was composed of the tidal generator, attenuation area and channel. Also, wave height, current meter and conductivity meter were used with the measured instruments in hydraulic scale model. NaCl with a tracer was used to evaluate the advection phenomena under the different velocity profiles. The arrival time of the maximum concentration in the condition of the relatively fast velocity was measured about 30 seconds faster than ones in the conditions of low velocity. The measured concentrations of the tracer were shown in the detection points of the flow direction consecutively.

• 한국전문물리치료학회지
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• 제10권3호
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• pp.1-15
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• 2003

The purpose of this study was to assess the effect of visual block (eyes open or closed), mental task type, and participation in an exercise program on static balance in the elderly. The subjects were 34 elderly (>65 years old) residents of a social welfare institute in Gyeonggi-do. We measured the following variables. Berg balance scale, mini mental state examination, balance performance monitor (sway area, path, and maximal sway velocity), age, weight, height and whether the subject participated in an exercise program. Scores for the Berg balance scale and mini mental state examination were evaluated to assess static balance ability either alone (single task paradigm) or while performing a mental task (dual task paradigm). Static balance variables that were measured included sway area, path, and maximal sway velocity. Each test was repeated three times. Multiple regressions analysis was used to examine the effect of each variable on static balance ability. For the dual task paradigm, static balance was affected by whether the subject participated in an exercise program. The Berg balance scale score for subjects with their eyes open was affected by whether they participated in an exercise program, while this variable in addition to the height and weight of subjects were determining variables in subjects with their eyes closed. As a result, whether subjects participated in an exercise program affected their static balance irrespective of whether their eyes open or closed. Therefore, regular exercise is recommended for elderly people and further research is needed to examine the relationship between static and dynamic balance while performing mental tasks such as cognition and attention.

• 터널과지하공간
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• 제17권6호
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• pp.503-510
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• 2007

석회석 광산에 굴착된 대규격 갱도의 안정성을 평가하기 위하여 22곳의 측정지점을 선택한 후 RMR과 Q 분류법을 실시하였다. 측정 대상 갱도가 조사시점까지 안정성에 심각한 문제가 없었다는 점을 고려하면 갱도 폭에 대한 안정성을 평가함에 있어 RMR보다는 Q 분류법이 측정 결과와 부합하는 것으로 나타났다. 갱도의 전체적인 안정성을 평가하기 위하여 수정 Q 분류법의 일종인 확장 안정성 도해법을 적용한 결과 한 곳을 제외하고는 모든 측정 갱도들이 안정한 것으로 평가되었다. RMR과 Q 분류법의 적용 결과를 토대로 하여 대규격 갱도의 최대 무지보 폭과 한계높이를 평가할 수 있는 회귀식을 제안하였다.

• Composites Research
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• 제34권5호
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• pp.330-336
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• 2021

알루미나 파우더는 산업용으로 널리 사용되는 소재 중 하나이지만 파우더 패킹 상태에 따라 제품의 강도가 변하는 문제점이 있다. 위 문제해결을 위하여 입자 패킹효율을 높이려는 많은 선행연구들이 수행되었지만, 기존 연구는 밀리미터 스케일의 입자의 충진 특성을 분석한 것이 대부분이므로 마이크로미터 스케일과 물리적 특성이 달라, 그 선행연구 결과를 토대로 마이크로미터 스케일에 적용하기 어렵다. 따라서 본 논문에서는 마이크로미터 스케일의 알루미나 파우더를 이용하여 충진률을 높이기 위하여 통계적방법을 이용하여 3단계 실험을 수행하였다. 먼저, 혼합물시험계획법을 이용하여 충진율이 높은 크기 조합 및 혼합 비율을 선정하였으며, 진동 실험장치에서 가진 주파수 변경에 따른 충진 높이 변화를 분석하여 적정 가진 주파수를 선정하였다. 마지막으로 앞서 언급한 실험 결과값을 토대로 알루미나 파우더 충진율 시험을 수행하였다. 그 결과, 최대 높이 변화량은 충진 크기조합 선정을 위해 수행한 최초의 실험 결과 최댓값보다 42% 향상된 것을 확인하였다.

• 천문학회보
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• 제43권2호
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• pp.52.3-53
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• 2018

We compare vertical profiles of the extraplanar $H{\alpha}$ emission to those of the UV emission for 38 nearby edge-on late-type galaxies. It is found that detection of the "diffuse" extraplanar dust (eDust), traced by the vertically extended, scattered UV starlight, always coincides with the presence of the extraplanar $H{\alpha}$ emission. A strong correlation between the scale heights of the extraplanar $H{\alpha}$ and UV emissions is also found; the scale height at $H{\alpha}$ is found to be ~0.74 of the scale height at FUV. Our results may indicate the multiphase nature of the diffuse ionized gas and dust in the galactic halos. The existence of eDust in galaxies where the extraplanar $H{\alpha}$ emission is detected suggests that a larger portion of the extraplanar $H{\alpha}$ emission than that predicted in previous studies may be caused by $H{\alpha}$ photons that originate from H II regions in the galactic plane and are subsequently scattered by the eDust. This possibility raise an advantage in studying the extraplanar diffuse ionized gas. We also find that the scale heights of the extraplanar emissions normalized to the galaxy size correlate well with the star formation rate surface density of the galaxies. The properties of eDust in our galaxies is on a continuation line of that found through previous observations of the extraplanar polycyclic aromatic hydrocarbons emission in more active galaxies known to have galactic winds.

• 한국의류산업학회지
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• 제1권2호
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• pp.127-136
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• 1999

The purpose of this research was to investigate the difference between perceptions of the nude body and of the clothed body as measured by body cathexis scale. Subjects were 274 college male and female between 20~30 yrs. Data were analyzed by using frequency, T test, cluster analysis, Duncan test by using Spss for window 8.0 PC program. Significant difference were found between mean scores of male and female on the nude body cathexis (NBC) and clothed body cathexis (CBC) Scales for hair texture, hair color, face, face color, shape of head, eye, lips, forehead, back, trunk, waist, bust, leg of shape, chest, hip. On the difference between male and female, significant differences were found between NBC and CBC scales for all body parts except hair texture, face color, ears, eyes, teech. Male had higher satisfaction than female in both body cathexis. The taller men, the higher body satisfaction with face shape, body shape, height in both body cathexis. Before appearence management, the bigger men, the higher body satisfaction with musle, waist, height, chest, body shape in both body cathexis. Male had higher satisfaction than female in both body cathexis. The taller women, the higher body satisfaction with neck, body shape, height in before appearence management. The bigger women, the higher body satisfaction with heights, weight distributions, waist, height in both.

• 한국수자원학회논문집
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• 제35권1호
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• pp.13-24
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• 2002

본 연구에서는 역학적으로 실질적이면서도 단순화된 방법으로 폭풍과 같은 악후시에 임의의 해안단면에서 발생하는 소상파의 수동학적 거동에 대한 예측모델을 개발하고자 한다. 실제 크기의 폭풍과 조건하에서 사구의 침식을 모의하기 위해 수행된 대형조파수조 실험에서 계측된 실험자료가 모델 개발을 위해서 활용된다. 일반적으로 본 모델은 해안종단방향에서의 소상파의 파고, 속도 및 주기의 변화를 예측할수 있음을 보인다. 정량적으로 보다 나은 소상파 변수들에 대한 예측은 유의 소상파고가 영이 되는 해빈면의 높이, ymax에 대한 예측향상을 통하여 이루어질수 있다.

• Geomechanics and Engineering
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• 제14권2호
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• pp.131-139
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• 2018

The preparation of repeatable and uniformly reconstituted soil specimens up to the specified conditions is an essential requirement for the laboratory tests. In this study for large samples replication, the simultaneous usage of the traveling pluviation and curtain raining technique is used to develop a new method, called the curtain travelling pluviator (CTP). This simple and cost effective system is based on the air pluviation approach, whilst reducing the sample production time, can reproduce uniform samples with relative densities ranging from 25% to 96%. In order to investigate the resulting suitability and uniformity from the proposed method, a series of tests is performed. The effect of curtain traveling velocity, curtain width, drop height, and flow rate on the parameters of the sample is thoroughly investigated. Increase in the curtain velocity and drop height leads to the increase in relative density for the sand specimen. Increase in curtain width typically resulted in the reduction of relative density. Test results reveal that the terminal drop height for the sand specimen in this study is more than 500 mm. Relative density contour lines are presented that can be utilized in optimizing the drop height and curtain width parameters. Sample uniformity in the vertical and horizontal orientation is investigated through the sampling containers. Increasing relative density tends to result in the higher sample repeatability and uniformity.

• Wind and Structures
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• 제34권4호
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• pp.355-369
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• 2022

Section model test, as the most commonly used method to evaluate the aerostatic and aeroelastic performances of long-span bridges, may be carried out under different conditions of incoming wind speed, geometric scale and wind tunnel facilities, which may lead to potential Reynolds number (Re) effect, model scaling effect and wind tunnel scale effect, respectively. The Re effect and scale effect on aerostatic force coefficients and aeroelastic characteristics of streamlined bridge decks were investigated via 1:100 and 1:60 scale section model tests. The influence of auxiliary facilities was further investigated by comparative tests between a bare deck section and the deck section with auxiliary facilities. The force measurement results over a Re region from about 1×10⁵ to 4×10⁵ indicate that the drag coefficients of both deck sections show obvious Re effect, while the pitching moment coefficients have weak Re dependence. The lift coefficients of the smaller scale models have more significant Re effect. Comparative tests of different scale models under the same Re number indicate that the static force coefficients have obvious scale effect, which is even more prominent than the Re effect. Additionally, the scale effect induced by lower model length to wind tunnel height ratio may produce static force coefficients with smaller absolute values, which may be less conservative for structural design. The results with respect to flutter stability indicate that the aerodynamic-damping-related flutter derivatives 𝘈^*₂ and 𝐴^*₁𝐻^*₃ have opposite scale effect, which makes the overall scale effect on critical flutter wind speed greatly weakened. The most significant scale effect on critical flutter wind speed occurs at +3° wind angle of attack, which makes the small-scale section models give conservative predictions.

• Journal of Advanced Marine Engineering and Technology
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• 제34권2호
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• pp.235-242
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• 2010

본 연구는 열교환기의 가열된 표면위에 부착된 지열수 스케일의 조도 영향을 검증하기 위한 강제 대류 열전달에 관한 실험적 연구이다. 실험은 원형 원관 위에 5종류의 실리카 스케일 입자를 균일하게 부착하여 행하였다. Reynolds수는 13,000에서 50,000의 범위에서 행하였다. 국소와 평균 열전달 특성은 스케일 입자 크기와 레이놀즈수의 함수로서 측정하였으며 평균오염저항을 이들의 결과로부터 평가하고 그들의 특성들을 분석 하였다. 원관의 열전달 특성은 지열수 스케일의 오염에 의해, 특히 입자 크기에 의해 크게 변화하였다. 또한 국소와 평균 Nusselt수는 원관 간격과 Reynolds 수에 의해 크게 의존 되었다.