• Structural Engineering and Mechanics
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• 제72권4호
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• pp.409-420
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• 2019

The paper presents the results of an experimental and numerical programme to characterize the behaviour of steel beams reinforcement by composite plates. Important failure mode of such plated beams is the debonding of the composite plates from the steel beam due to high level of stress concentration in the adhesive at the ends of the composite plate. In this new research, an experimental and numerical finite element study is presented to calculate the stresses in the sika carbodur and sika wrap reinforced steel beam under mechanical loading. The main objective of the experimental program was the evaluation of the force transfer mechanism, the increase of the load capacity of the steel beam and the flexural stiffness. It also validated different analytical and numerical models for the analysis of sika carbodur and sika wrap reinforced steel beams. In particular, a finite element model validated with respect to the experimental data and in relation to the analytical approach is presented. Experimental and numerical results from the present analysis are presented in order to show the advantages of the present solution over existing ones and to reconcile debonding stresses with strengthening quality.

• 한국태양에너지학회 논문집
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• 제31권4호
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• pp.103-111
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• 2011

Laser drilling of vias is the one of key technologies in developing Emitter-Wrap Through(EWT) solar cell which is particularly attractive due to the use of industrial processing and common solar grade p-type silicon materials. While alternative economically feasible drilling process is not available to date, the processing time and laser induced damage should be as small as possible in this process. This paper provides an overview on various factors that should be considered in using the laser via drilling technology for developing highly efficient and industrially applicable EWT solar cells.

• 설비공학논문집
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• 제18권5호
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• pp.434-442
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• 2006

In a two-stage compression $CO_2$ transcritical cycle, application of a scroll expander-compressor unit has been considered in order to improve the cycle COP. For both expander and 1st stage compressor, scroll wrap profile which was originally designed for a R410A air-conditioning cycle mechanism was used with minor modifications: wrap height and involute end angle were adjusted for required displacement volume and built-in volume ratio. For pressure condition of 10 Mpa/3.5 MPa and expander inlet temperature of $35^{\circ}C$, 25% improvement in COP was obtained by using expander-compressor unit. As evaporator pressure increased, COP improvement was lowered mainly due to decreasing compressor peformance.

• Archives of Plastic Surgery
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• 제49권6호
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• pp.764-768
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• 2022

The wrap-around flap (WAF) has become a popular approach to thumb reconstruction because the results are functionally and cosmetically excellent. By modifying to a partial toenail transfer, the WAF can also be used for finger reconstruction. However, performing cosmetically superior finger reconstruction is a significant challenge because it is difficult to reconstruct the natural nailfold by partial nail transplantation, although partial nail transplantation is required to reconstruct a narrow fingernail. One side of the reconstructed lateral nailfold tends to be a missing nail margin, and one side of the proximal nailfold angle tends to be retracted. Based on the rationale that loss of the lateral nailfold volume due to the postoperative tension of the volar flap would result in a missing nail margin, the volume of the lateral nailfold was maintained with a single thread that was passed from the nail to the volar flap. Additionally, half of the proximal nailfold from the nail plate was elevated to advance it forward. The results indicated that a cosmetically natural nailfold was achieved with the WAF approach to finger reconstruction. These easy and simple techniques enable reconstruction of a cosmetically natural nailfold using WAF for finger reconstruction.

• 한국환경농학회지
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• 제33권4호
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• pp.403-408
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• 2014

난온대성 낙엽과수인 참다래는 겨울철 동해에 민감하여 주산지역에서도 월동기에 주간을 피복하고 있다. 본 연구는 참다래 재배에서 월동기 주간부 동해 예방을 위해 사용되고 있는 피복재의 온도특성에 대해 알아보고자 하였다. 실험은 경남 사천의 5-6년생 '헤이워드' 과수원에서 이루어 졌다. 사용된 피복재는 볏짚과 은박쿠션 2종류였으며, 낙엽후인 12월 하순에 설치하여 이듬해 4월 중순에 제거하였다. 피복재 내부의 온도 측정은 WatchDog 2450 (Spectrum Technologies, Inc.)을 이용하여 2013-2014년1-3월에 측정 비교하였다. 1월과 2월 최저기온이 각각 $-10.2^{\circ}C$, $-10.9^{\circ}C$로 추웠던 2013년에 은박쿠션 내부의 최저기온은 1, 2월에 각각 $-6.3^{\circ}C$, $-2.6^{\circ}C$로 보온효과가 뛰어났다. 반면, 볏짚 내부의 1, 2월 최저기온은 각각 $-9.8^{\circ}C$, $-9.9^{\circ}C$로 대기 온도와 큰 차이가 없어 보온효과가 미미했다. 측정 시각에 따른 평균기온의 변화에서도 은박쿠션이 볏짚에 비해 낮 동안의 열을 피복재 내부에 잘 간직하여 야간 온도를 상대적으로 높게 유지했다. 따라서 참다래 나무의 월동 피복 자재로써 은박쿠션이 볏짚에 비해 보다 효과적일 것으로 판단되었다.

• Archives of Reconstructive Microsurgery
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• 제9권2호
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• pp.120-126
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• 2000

저자들은 1992년 7월부터 수부에서 연부 조직이 손상되어 결손된 부위를 신경감각 유리 피부판을 이용하여 재건하여 평균 5년 11개월 추시하였다. 수부에서 적절한 신경감각 유리 피부판은, 절개와 문합시 미세 수술이 가능하도록 충분한 직경과 길이를 가진 혈관이 존재하여야 하며, 피부판에 존재하는 신경은 임계 감수성이 가장 중요하며, 때로는 방어 감수성을 향상시키기 위하여 선택되어져야 한다. 포장 주위 유리 피부판은, 족부의 제 1 협부-공간 피부판과 족지-수질 피부판과 함께 임계 감수성을 향상시키기 위한 중요한 피부판이지만, 수부에서 결손 부위, 그리고 결손 부위의 특수한 상황과 결손 부위가 넓은 경우에는, 2차적으로 방어 감수성의 향상을 위하여 족 배유리 피부판이나 외 상완 피부판 등이 선택되어 질수 있다. 저자들이 치험한 수부 무지의 재건에 이용한 포장 주위 피부판 4례는 임계 감수성이 우수하고, 2점 감별 검사에서 양호한 결과를 보였다.

• 한국연초학회지
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• 제21권2호
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• pp.109-118
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• 1999

A model predicted describing the effect of cigarette making materials on the level of filter ventilation was developed and evaluated. The developed model was expressed in terms of a linear and quadratic relationship which was validated with experimental measurements for different porosity of plug wrap and tipping paper, unencapsulated pressure drop of filter plug and cigarette column and vent position. Forty-six experimental frequencies were determined as a result of using three levels with five factors Box-Behnken design and analyzed by the multiple regression analysis with backward stepwise in STATISTICA/PC under restricted conditions. The four factors, except filter pressure drop variable, were statistically significant at the level of 0.05 but most of all linear by linear interactions were comparatively lower significant. By the analysis of linear and quadratic regression coefficient, filter ventilation of the cigarette was affected by porosity of plugwrap (5.87, -4.25), porosity of tip paper (5.68, -1.00), vent position (-3.87, 3.08), tobacco column pressure drop (2.56, 0.66), and filter pressure drop (1.50, 0.58) in the decreasing order. It should be emphasized that the major conclusion of this study was not that any particular parameter was linear or quadratic on any limit scale, but that there were highly significant relationships among factors involving linear, quadratic and their interaction and perhaps even linearity between and within factors. While, there is also quite strong evidence that vent position from mouth end and cigarette making materials are reverse relationship on this experimental model. On the basis of the result, it can be concluded that the porosity of the plug wrap and tipping paper has a marked effect on degree of filter ventilation rate. The F-value of plug wrap and tipping paper porosity among five factors were 39.2 and 36.8 respectively with P-value of 0.000 indicating higher significant for both factors. According to the analysis of variance, the model fitted for filter ventilation was significant at 5% confidence level and the coefficient of determination ($R^2$=0.84) was the proportion to variability in the data well fitted for by the model.

• 한국식품과학회지
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• 제30권5호
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• pp.1140-1145
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• 1998

대황추출물, 황련추출물, 지르코니움계 은치환무기 이온교환체 등의 항균성 소재를 1% 농도로 함유시킨 LDPE 필름($O_2$, 투과도 : $68{\sim}80\;mL/m^2$ atm hr, $CO_2$ 투과도 : $304{\sim}360\;mL/m^2$ atm hr)을 사용하여 200 g 단위의 딸기에 대해서 환경기체조절포장을 실시하고 $5^{\circ}C$에서 저장하면서 포장내 기체조성, 미생물 증식, 물리화학적 품질변화를 측정하였다. 또한 대황추출물 함유 필름의 포장에 0.5 mm의 핀홀을 2개 낸 세공성 포장, 항균제 무첨가의 대조구 LDPE 밀봉포장, PVC wrap 포장과도 비교하였다. 항균성 LDPE 필름은 포장된 딸기의 총균수, 유산균수, 효모수에서 미생물의 생육을 억제하였고, 밀봉포장될 때 4% 이하의 낮은 $O_2$ 농도 및 $6.3{\sim}9.0%$의 $CO_2$ 농도의 변형기체조성을 유지하였다. 포장필름의 미생물생육억제와 변형기체의 복합적인 상승 효과로 인해 항균성 LDPE 밀봉포장은 대조구 LDPE 포장, 통기성의 PVC wrap 및 세공성 핀홀 포장에 비해 현저하게 낮은 부패율을 보였다. 그리고 이러한 포장은 딸기의 경도 유지에도 긍정적인 효과를 가짐과 아울러 다른 물리화학적 변화에도 부정적인 영향을 주지 않았다.

• 한국도로학회논문집
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• 제15권2호
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• pp.29-37
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• 2013

PURPOSES : This study aims to review the possibility of developing a road snow-melting system that can prevent slip accidents by maintaining a constant temperature of the winter roads and enhance performance of structures, including improvement of compressive strength by mixing carbon nanotube (hereafter referred to as CNT) with cement paste, the basic material. METHODS : To achieve the above purpose, an experiment was conducted by mixing power-type CNT and wrap-type CNT up to cement paste formulation by weight of 0.0wt%~4.1wt% in accordance with "KS L ISO 679(of cement strength test method)", and compressive strength was measured at 28 days of curing. In addition, the volume resistivity of the specimen was measured to test thermal and electrical characteristics, and the rate of temperature changes in specimen surface by power consumption was measured by passing electricity through the cross-sections of the specimen. Meanwhile, the criteria for checking the performance as a road snow-melting system was determined as volume resistivity of $100{\Omega}{\cdot}cm$ or less. RESULTS : A comparative analysis between specimen with 0wt% CNT content in plain status and specimen containing various types of CNTs was carried out. From its results, it was found that compressive strength increased approximately 19%, showing the highest rate when 0.2wt% of wrap-type CNT was contained, but volume resistivity of $100{\Omega}{\cdot}cm$ or less appeared only in specimens containing more than 0.2wt% CNT. In addition, it was observed that the surface temperature increased by $4.62^{\circ}C$ per minute on average in specimens containing 3.2wt% CNT. CONCLUSIONS : In this study, CNT was examined as an underlying material for a road snow-melting system, and the possibility of developing the road now-melting system was reviewed by conducting various experiments using CNT-Cement composites. From the experimental results, the specimens were found to have a superior performance when compared to the existing road snow-melting systems that place the heat transfer medium such as copper on the road. However, satisfactory strength performance were not obtained from the specimen containing CNT(2.0% or more) that functions as a heating element, which leads to the need for reviewing methods to increase the strength by using plasticizer or admixture.

• 농업과학연구
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• 제45권2호
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• pp.211-218
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• 2018

Different packaging methods and storage temperatures were tested to determine the storage stability of beef dry-aged for 21 days based on microbial, physicochemical, and sensory qualities. After completion of the dry aging, the dried surface of beef sirloin was trimmed off, and the beef was packaged using two different methods (oxygen-permeable wrap or vacuum packaging) and stored at different temperatures ($3{\pm}2^{\circ}C$ or $-23{\pm}2^{\circ}C$) for 0, 7, 14, or 21 days. Lipid oxidation and the sensory quality of the dry-aged beef were not affected by the packaging method and storage temperature during storage. No microbial growth was observed over the storage period in the vacuum-packaged dry-aged beef, regardless of the storage temperature. However, dry-aged beef in the oxygen-permeable wrap packaging showed microbial spoilage with 8.82 log CFU / g at day 7 of the refrigerated storage. The vacuum-packaged dry-aged beef showed the lowest values (p < 0.05) in $a^*$ and chroma at days 14 and 21 at $3^{\circ}C$, and days 7 and 14 at $-23^{\circ}C$, respectively. Therefore, it is recommended that dry-aged beef with wrap packaging stored in refrigerated conditions should be consumed as quickly as possible due to microbial growth. For long-term storage, dry-aged beef should be frozen because freezing can extend the color stability up to day 21 of storage without adverse effects on the hygienic or meat quality aspects of dry-aged beef.