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- 저자 : 최승렬 (검색결과 130 건)
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Measurement of Fiber Board Poisson’s Ratio using High-Speed Digital Camera
최승렬,최동수,오성식,박석호,김진세,천호현 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.4
Purpose: The finite element method (FEM) is advantageous because it can save time and cost by reducing the number ofsamples and experiments in the effort to identify design factors. In computational problem-solving it is necessary that theexact material properties are input for achieving a reliable analysis. However, in the case of fiber boards, it is difficult tomeasure their cross-directional material properties because of their small thickness. In previous research studies, thePoisson’s ratio was measured by analyzing ultrasonic wave velocities. Recently, the Poisson’s ratio was measured using ahigh-speed digital camera. In this study, we measured the transverse strain of a fiber board and calculated its Poisson’s ratiousing a high-speed digital camera in order to apply these estimates to a FEM analysis of a fiber board, a corrugated board,and a corrugated box. Methods: Three different fiber board samples were used in a uniaxial tensile test. The longitudinalstrain was measured using the Universal Testing Machine. The transverse strain was measured using an image processingmethod. To calculate the transverse strain, we acquired images of the fiber board before the test onset and before thefracture occurred. Acquired images were processed using the image processing program MATLAB. After the images wereconverted from color to binary, we calculated the width of the fiber board. Results: The calculated Poisson’s ratio rangedbetween 0.2968–0.4425 (Machine direction, MD) and 0.1619–0.1751 (Cross machine direction, CD). Conclusions: This studydemonstrates that measurement of the transverse properties of a fiber board is possible using image processing methods. Correspondingly, these processing methods could be used to measure material properties that are difficult to measure usingconventional measuring methodologies that employ strain gauge extensometers.
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최승렬,Choi, Sung-Yul 대한예방의학회 1973 Journal of Preventive Medicine and Public Health Vol.6 No.1
1. Introduction Community medicine with the concept of comprehensive medical care and an ideal medical care delivery system not only for an individual or family but for the whole community has emerged. In April 1970, the Presbyterian Medical Center started a hospital based community health service project in order to improve the health of the people in rural areas. Prior to commencing a comprehensive medical care system, a family survey was needed. The major objective of this survey was to obtain information concerning the people and their environment so as to be able to plan and implement a comprehensive medical care program in Soyang-Myun. 2. Survey Method An interview using a family record form was carried out for each household. This family record form was designed to get information about demography, family planning, environmental sanitation and vital statistics. Prior to beginning, the members of the survey team were trained in interviewing techniques for three days. The team consisted of a public health nurse, four nurse-aides, a sanitarian and four health extension workers who are working in our project, The survey was carried out during the period November 1971 to March 1972. 3. Project area 1) Population of Soyang-Myun was 11,668; male, 5,962 and female, 5,706. Sex ratio: 104.5. 2) Households : 1,858 3) Family size: The average household consisted of 6.3 persons. 4) Educational level of householder a. Illiterate 13% b. No schooling but able to read 10% c. Preschool children 19% d. Primary school 47% e. Middle school 7% f. High school 3% g. College or University 1% 5) Occupational distribution of householders a. Farmer 67% b. Laborer 13% c. Office worker 4% d. Merchant 4% e. Industrial worker 2% f. Unemployed 8% g. Miscellaneous 2% 6) Religious affiliation a. No religion 74% b. Buddhist 12% c. Protestant 10% d. Catholic 4% 4. Survey results Living Environment : a. Home ownership 95% b. Kinds of roofing Straw-thatched house 84% Tile-roofed house 10% Slate-roofed house 5% Other 1% c. Floor space Less than 6 pyong 10% 6-10 pyong 53% 11-15 pyong 24% 16-20 pyong 9% More than 20 pyong 4% d. Radio ownership 80% Environmental Sanitation : a. the source of drinking water public well 49% private well 30% drainage water 9% steam water 8% well pump 3% water distribution system 1% b. Distance between well and toilet more than 16meters 38% 6-10 meter 31% 11-15 meters 14% Less than 6 meters 17% c. The status of well management Bad 72% Fair 26% Good 2% d. General sanitary state of house Bad 37% Fair 51% Good 12% e. House drainage system had no house drainage. 77% Family Planning : a. 24% of the people have used contraceptives, but 12% ceased to use them. 76% have never used contraceptives. b. used methods 1oop 68% oral pill 16% vasectomy 4% condom 1% tubal ligation 1% two or more methods 10% Maternal Health : a. The number of conceptions of housewives under 50 years of age. 11 times 26% 6 times 11% 5 times 11% 4 times 9% b. The place of delivery own house 88% hospital 1% others 11% Treatment of general sickness : a. The place of treatment Soyang Health Center 31% Hospital (private or otherwise) 26% Pharmacy 14% Herb medicine 5% Private care 5% No treatment 12% Miscellaneous 7% b. Usual causes of diseases Unknown 46% Tuberculosis 29% Neuralgia 8% CVA 3% Bronchitis 3% Others 11%
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최승렬,정훈,최동수 한국포장학회 2013 한국포장학회지 Vol.19 No.3
본 연구에서 개발된 멜론용 펄프몰드난좌의 진동전달특성을 구명하고 모의수송시험을 통해 적합성을 분석하였다. 멜론 펄프몰드 난좌의 중량이 증가할수록 압축강도는 상승하 였고, 완충성능이 증가하는 것으로 나타났다. RMS 평균 가 속도의 진동전달률을 살펴보면 펄프몰드 난좌의 중량이 증 가할수록 진동전달률이 감소하는 경향을 보였다. 골판지 180 g 신문고지 50 g을 배합한 펄프몰드난좌의 경우 가진되 는 진동가속도보다 큰 진동가속도가 전달되는 것으로 나타나 멜론의 포장에 적합하지 않은 것으로 나타났고, 골판지 200 g 신문고지 50 g을 배합한 펄프몰드난좌의 진동전달률이 가장 작게 나타나 멜론의 포장에 가장 적합한 것으로 나타 났다. 또한, 기존 상자포장보다는 펄프몰드난좌 포장 시 진 동의 전달이 작은 것을 알 수 있었으며, 펄프몰드 난좌의 중 앙에 위치한 멜론과 비교하여 주변에 위치한 멜론에 전달되 는 진동가속도가 큰 것을 알 수 있었다. 기존 상자포장과 펄프몰드난좌 포장의 모의 수송시험을 실 시하여 경도를 측정 한 결과, 무가진 멜론에 비하여 경도저하가 나타났지만, 난좌를 이용하여 포장하였을 때 기존 상자포장에 비하여 멜론 의 경도 유지 효과가 우수함을 알 수 있었다. 따라서 본 연구결과 펄프몰드 난좌를 이용한 멜론포장은 수송 중 진동에 의한 품질저하 요인을 감소시켜 상품성 유지에 효과적인 방 법이라 판단된다. In order to protect agricultural products against damage by physical load, various shock absorbing materials is used. As the demands of environment protection increase, the use of plastic materials have been restricted. On the other hand, Pulp mold products have some benefits - easy manufacturing, superior shock absorbing and eco-friendly. In order to develop pulp mold tray for melon packaging as shock absorbing packaging material, we investigated physical properties and vibration transmission characters of 180, 200 and 220 g pulp mold tray for melon. As the weight of pulp increased, compression strength and shock absorbing performance increased, while vibration transmissibility decreased. Especially in case of 180g pulp mold tray, it is not suitable for melon packaging because the transmitted vibration acceleration was higher than the forced vibration acceleration. And 200g pulp mold tray is suitable for melon packaging because the vibration transmissibility was lowest in three trays. And the vibration acceleration transmitted to the melon in edge of pulp mold tray was higher than to the melon in center of pulp mold tray. As the result of the simulated transportation test, the firmness of melon packaging using pulp mold tray was higher than that of conventional packaging. Therefore, these results suggest that pulp mold tray packaging could be suitable for melon packaging.
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