• 청정기술
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• 제30권3호
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• pp.239-247
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• 2024

The removal of volatile organic compounds (VOCs) from spent polypropylene (PP) sourced from the bumpers and interiors of used cars was carried out by using high-temperature supercritical carbon dioxide (scCO₂) extraction. The recycled polymers from the bumpers and interiors contained other additives beside PP such as polyethylene (PE), talc, and carbon black, which modified the properties of PP. The crystallinity of the recycled bumper and interior PP was significantly lower than that of the virgin PP pellet. The decomposition temperatures of the recycled bumper and interior PP was slightly higher than that of the virgin PP pellet, while the melting and crystallization points were slightly lower. The effect of process conditions on VOC removal was studied by varying the time (2 ~ 720 min), pressure (6.4 ~ 14 MPa), and temperature (298 ~ 473 K). Since VOC removal at 2 min produced satisfying results, times below 2 min (10 ~ 120 s) were also studied. The main goal of scCO₂ extraction was to reduce the xylene content, as the xylene content of the recycled bumpers was higher than the allowable limit. A temperature above 373 K was needed to remove the xylene from the waste PP samples. The optimum condition for VOC removal from bumper waste was determined to be 433 K, 8 MPa, and 60 s. The car interior waste had VOC content within the allowable limit, so no further treatment was needed.

• 사상체질의학회지
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• 제23권1호
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• pp.63-78
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• 2011

1. Objectives: We aimed to propose a sub-classification system for the Taeeumin symptomatology by examining the Taeeumin pathology and symptomatology descriptions appearing in "Donguisusebowon". 2. Methods: The Gabo Edition and the Sinchuk Edition (the upgraded and revised edition) of "Donguisusebowon" were reviewed and examined for relevant information on the Taeeum pathology and symptomatology. 3. Results and Conclusions: 1) In the Taeeumin symptomatology, the Exterior disease develops from the basic pathology of Esophagus-Cold and the Interior disease from that of Liver-Heat, eventually progressing to damage of the expirational and dispersive energy of the Lung Sector, the Prime Core Organ or the excessively small organ of the Taeeum constitutional type. The resulting pathology can be broadly defined as the "Lung-Dryness symptomatology". 2) The case reports introduced in the Exterior disease section, including the Zhang Zhongjing Mahuang-tang treatment, Prolonged-affliction disease treatment, and Exterior disease Pestilential disease treatment, share several points in common. They all arise from the pathology of "weakness in the Lung sector and deficiency in the Exterior sector", and they can all be assigned to the same symptomatological division that presents with systemic heat and cold intolerance; this symptomatology can be defined as the "Esophagus-Cold symptomatology", the milder subdivision of the exterior symptomatology. 3) The body of text appearing in the last part of the Interior disease section commonly referred to as the "Taeeumin Conspectus" is in fact not a conspectus when its contents are actually examined. Instead, it can be understood from its pathological and symptomatological descriptions that the passage is explaining the more severe subdivision of the exterior symptomatology that has progressed from Esophagus-Cold to a pathology characterized by damaged expirational and dipersive energy of the Lung Sector. 4) The relocation of the "dry-related pathology" indicates a change in perspective regarding the "Dry-related symptomatology", which caused the rearrangement of the Interior disease into divisions of Liver-Heat symptomatology that is characterized by fulminant heat pathology and Dry-Heat symptomatology that is also accompanied by Lung-Dryness. 5) The Interior disease Yin-Blood Consumptive symptomatology should be included in the Dry-Heat symptomatology in the pathological scheme. 6) Based on the above, the subdivisions of the Taeeumin symptomatology should be arranged as "Esophagus-Cold symptomatology" and "Lung-Dry-Cold symptomatology" in the Exterior disease and "Liver-Heat symptomatology" and "Dry-Heat symptomatology" in the Interior disease.

• 대한불안의학회지
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• 제18권2호
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• pp.56-64
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• 2022

Objective : Creating a psychologically stable indoor environment is a significant factor in modern life. This study was conducted to confirm which type of wood interior decorating environment was beneficial for improving depression and anxiety. Methods : A total of 59 participants will randomly assign to each accommodation by dividing the rest of the three setting with the same structure with 0% wood interior decorating environment, 45% wood environment, and 90% wood environment. The Psychological evaluation measured at three time points, was before exposure to the wood environment (T1), 45 minutes after exposure to the wood environment (T2), and 20 hours after exposure to the wood environment (T3). Results : As a result of examining the effect of the wood interior use ratio on psychological variables, After about 20 hours (T3), there were significant differences in mood state_vigor-activity(𝛘²=7.253, p<0.05), mood state_tension-anxiety (𝛘²=7.041, p<0.05), mood state_anger-hostility(𝛘²=8.318, p<0.05), and state anxiety (𝛘²=7.680, p<0.05). State anxiety also showed a significant difference in T2 (𝛘²=8.811, p<.05). As a result of analyzing the effect on satisfaction and subjective impression, there was a significant difference in satisfaction (𝛘²=6.300, p<0.05) and 'pleasant (𝛘²=6.930, p<0.05), airy (𝛘²=6.628, p<0.05), masculine (𝛘²=6.906, p<0.05), ordinary(𝛘²=6.662, p<0.05), natural (𝛘²=13.924, p<0.001), calm (𝛘²=13.106, p<0.001), safe (𝛘²=7.755, p<0.05)'. Conclusion : The wood interior decorating environment had a positive effect on anxiety and mood, such as lowering depressive and anxious mood and increasing positive changes and as the ratio of wood decoration increased, it had a greater positive effect on emotions.

• 한국실내디자인학회논문집
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• 제24권6호
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• pp.202-211
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• 2015

This study attempts to deduce the necessity and validity of complexation, and suggests complexation through complexation suitability evaluations as follows. First, the concept and current state of leisure facilities for the elderly and elementary facilities and architectural complexation were investigated through theoretical considerations. Second, the target schools for complexation of 'elementary school-leisure facility for the elderly' were selected. The aspects of facility introduction of an elementary school, teacher support facility, convenience facility for the disabled, safety and security facilities as well as school facility accessibility were investigated on the basis of the data attained from theoretical considerations. Third, the feasibility of complexation of leisure facilities for the elderly was reviewed, based on the investigated data on complexation-targeted elementary school. Regarding school building and support facilities, with a focus on leisure programs for the elderly, the availability and number of rooms, extra numbers of regular classrooms and the room condition were assessed on the basis of the analysis of operational perspective of each facility. The convenience facilities for the disabled were examined by classifying them into interventional facility in consideration of facilities for the elderly, pursuant to the provisions in the convenience promotion assurance act for the disabled, elderly and pregnant women. Safety and security facilities were evaluated in an effort to assess the safety issue of the elderly and children. The result of the evaluation of the 6 elementary schools in Seong-buk county based on the above-mentioned four measurement standards shows that they scored 107~124 points out of the total 155 points, with the average of 118.5 points. This is more than the medium score and shows the possible complexation of the elementary school facilities as the leisure facilities for the elderly, and at the same time it may lead each school to find out the elements conducive to enhancing the complexation as a result of the evaluation. Through the evaluation data, I expect that we contribute to promoting the process of the evaluation of the appropriateness of complexation and the efficient complexation.

• 환경영향평가
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• 제25권6호
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• pp.432-441
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• 2016

본 연구에서는 도심 내 단절되어 있는 서식지의 연결성을 고려하여 생태통로를 구축하고자 하는 선행연구로 서울시의 인왕산과 안산의 생물 종 분포를 예측하였다. 연구대상지역인 인왕산과 안산의 생물 종 분포는 출현자료만으로도 결과를 예측할 수 있는 Maxent(Maximum Entropy Approach) 모형을 이용하여 분석하였다. Maxent 모형을 활용하여 종 분포를 예측하기 위해, 출현자료는 포유류 23개 지점과 박새류(Parus major, P. palustris, P. varius) 3종 15개 지점을 활용하였다. Maxent 모형의 환경변수로는 지형인자 4가지, 식생인자 4가지와 거리인자 2가지를 대상으로 구축하였다. 이 변수들을 활용하여 종 분포를 예측한 결과, 포유류의 경우에는 수치표고자료(DEM)가 34%, 산림지역의 경계로부터 산림내부의 거리가 24.8%, 수종이 10% 순으로 종 분포 모형에 기여도가 높았다. 반면 박새류의 경우에는 수치표고자료가 39.6%, 도로로부터의 거리가 35.4%, 나무의 밀도가 8.2% 순으로 모형에 기여도가 높았다. 따라서 조류 및 포유류는 산림 내부지역을 선호하는 것으로 나타났으며, 이 지역 보전이 필요한 것으로 판단된다.

• Structural Engineering and Mechanics
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• 제53권4호
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• pp.703-723
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• 2015

In this paper optimization of volume fraction distribution in a thick hollow cylinder with finite length made of two-dimensional functionally graded material (2D-FGM) and subjected to steady state thermal and mechanical loadings is considered. The finite element method with graded material properties within each element (graded finite elements) is used to model the structure. Volume fractions of constituent materials on a finite number of design points are taken as design variables and the volume fractions at any arbitrary point in the cylinder are obtained via cubic spline interpolation functions. The objective function selected as having the normalized effective stress equal to one at all points that leads to a uniform stress distribution in the structure. Genetic Algorithm jointed with interior penalty-function method for implementing constraints is effectively employed to find the global solution of the optimization problem. Obtained results indicates that by using the uniform distribution of normalized effective stress as objective function, considerably more efficient usage of materials can be achieved compared with the power law volume fraction distribution. Also considering uniform distribution of safety factor as design criteria instead of minimizing peak effective stress affects remarkably the optimum volume fractions.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 추계학술대회논문집
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• pp.249-267
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• 1995

The purpose of this study is to analyze breast shape by age, to classify breast types and then to suggest brassiere size chart. The subject of anthropometric measurement were 232 women in 20's and 40's. The direct anthropmetric measurement were analyzed by mean, standard deviation, duncan test, T-test, ANOVA, factor & cluster analysis The results are as follows; 1) as a result of analysis for the measurements, according to the increase of age, the items of height were decreased and the items of width, depth, cir- cumference, length were increased, being obesity and breast points were dropped. So the volume and bottom area of 40's women's breast were lager than 20's women's. The width of breast points was bide by increasing of intereior. 2) as a result of factor analyxis, 5 factors were extracted as important factor of breast shapes(obesity of breast and location of breast point, breast height and volume, upper dimensions of breast/lower dimensions of breast, interior dimensions of breast/exterior dimensions of breast, volume of the lower part and drop of breast) 3) as a reslut of cluster analysis, the breast shape were classified into 4 types. namely, typel has the smallest volume, bottom area of breast and the slenderest breast, type2 was the second obesity type. type3 was middle sized type. type4 has much dropped, wide bottom area of breast and the biggest form. 4) To establish brassiere sizing system, the loss funtion was used to decide interval of under bust girth and cup size of size chart. 20 brassiere sizes were established and the size chart covers 92.2% of all subject.

• 대한치과기공학회지
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• 제36권2호
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• pp.111-118
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• 2014

Purpose: Production of dental prosthesis by a dental technician causes a loud noise. Thus, we investigated stress of dental technicians due to a noise using a structured questionnaire. Methods: A survey was conducted on working dental technicians across the country from July 2013 to November 2013; among 200 sets of survey distributed, 166 were completed and returned, and excluding the 11 that deemed unsuitable, 155 sets were used for statistics. The program SPSS 19.0 was used to analyze the correlation among the collected data. Results: The stress of noise was found to be 2.83/5 points (2.93/5 for physical stress, 2.72/5 for emotional stress). Recognition of noise was found to be 2.71/5 points (3.39/5 for recognition of noise, 2.64/5 for accidents caused by noise, 2.29/5 for experiencing disability due to noise). For general items, the highest stress were shown for the following catogories: by gender, females (p=.008); by position, chief engineer (p=.033); by monthly pay, 2.51M-3.0M KRW (p=.023); by interior comfort, 'very unpleasant' was the highest recognized (p=.014). For the effect of time exposed to noise, its stress (p=.000) and recognition (p=.000) rose with increase of time. Conclusion: Dental technicians performs tasks in work environments exposed to extreme noise. This research attempts to re-emphasize the necessity for improving the work environment for noise and provide measures of blocking noise and precaution.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.105-115
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• 2006

Thickness is a commonly used parameter in product design and manufacture. Its intuitive definition as the smallest dimension of a cross-section or the minimum distance between two opposite surfaces is ambiguous for intricate solids, and there is very little reported work in automatic computation of thickness. We present three generic definitions of thickness: interior thickness of points inside an object, exterior thickness for points on the object surface, and radiographic thickness along a view direction. Methods for computing and displaying the respective thickness values are also presented. The internal thickness distribution is obtained by peeling or successive skin removal, eventually revealing the object skeleton (similar to medial axis transformation). Another method involves radiographic scanning along a viewing direction, with minimum, maximum and total thickness options, displayed on the surface of the object. The algorithms have been implemented using an efficient voxel based representation that can handle up to one billion voxels (1000 per axis), coupled with a near-real time display scheme that uses a look-up table based on voxel neighborhood configurations. Three different types of intricate objects: industrial (press cylinder casting), sculpture (Ganesha idol), and medical (pelvic bone) were used for successfully testing the algorithms. The results are found to be useful for early evaluation of manufacturability and other lifecycle considerations.

• 한국정밀공학회지
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• 제23권9호
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• pp.200-207
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• 2006

In this paper a new approach which combines implicit surface scheme and NURBS surface interpolation method is proposed in order to generate a complete surface model from unorganized point cloud data. In the method a base surface was generated by creating smooth implicit surface from the input point cloud data through which the actual surface would pass. The implicit surface was defined by a combination of shape functions including quadratic polynomial function, cubic polynomial functions and radial basis function using adaptive domain decomposition method. In this paper voxel data which can be extracted easily from the base implicit surface were used in order to generate rectangular net with good quality using the normal projection and smoothing scheme. After generating the interior points and tangential vectors in each rectangular region considering the required accuracy, the NURBS surface were constructed by interpolating the rectangular array of points using boundary tangential vectors which assure C$^1$ continuity between rectangular patches. The validity and effectiveness of this new approach was demonstrated by performing numerical experiments for the various types of point cloud data.