• Journal of Biosystems Engineering
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• 제37권1호
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• pp.44-50
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• 2012

Purpose: The characteristics of in-transit vibration stress and possible damage to packaged apples were examined. Methods: A simulated transportation environment with a specific power density profile was used for vibration impact experiments to determine the resulting decrease in packaged apple quality. Apples with or without vibration stress were stored at low temperature ($5{\pm}0.8^{\circ}C$, 75-85% relative humidity) for 30 days. Statistically significant differences (p ${\leq}$ 0.05) were found between apples with and without vibration stress for concentration of oxygen ($O_2$; 11.2% and 14.1%, respectively; initially $29{\pm}0.4%$), carbon dioxide ($CO_2$; 26.4% and 21.8%; initially $1{\pm}0.2%$), and ethylene (79.4 ${\mu}LL^{-1}$ and 55.6 ${\mu}LL^{-1}$; initially $14.1{\pm}0.6{\mu}LL^{-1}$) in the headspace of a gas-collecting container after 30 days of storage. Results: Significant differences were also measured for apples with and without vibration stress with respect to soluble solid content (15.4% and 14.9%, respectively; initially $12.9{\pm}0.8%$ and $13.1{\pm}1.1%$), weight loss (10.1% and 8.2%), and firmness (139.7 kPa and 163.3 kPa; initially $213.8{\pm}6.2$ kPa and $209.1{\pm}7.9$ kPa) after 30 days of storage. Conclusions: The vibration stress clearly accelerated the degradation of apple quality during storage, resulting in increased weight loss, soluble solid content, and headspace $CO_2$ and ethylene production, and decreased firmness and headspace $O_2$.

• 펄프종이기술
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• 제48권3호
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• pp.91-98
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• 2016

Linerboards have been produced by recycling recovered paper such as old corrugated containers(OCC). Usually linerboards produced during summer season show weak strength compared with those of produced during winter. In order to cope with the weak strength of linerboards produced during summer, and to confirm uniform quality, it is important to understand the seasonal effect on strength properties. Effect of pulping temperature of the OCC for linearboard production was investigated by controlling pulping temperatures at $18^{\circ}C$ and $51^{\circ}C$. Low pulping temperature ($18^{\circ}C$) caused more generation of fines in stock. Consequently retention and drainage of linerboard defibrated at high pulping temperature ($51^{\circ}C$) were better than those of $18^{\circ}C$. Strength properties of handsheet at low pulping temperature were higher than those of high pulping temperature and it could be confirmed that low pulping temperature during winter is one reason of seasonal variation of recycled linerboard strength. It is considered that surface modification of OCC fibers by harsh pulping action during winter caused increase of paper strength.

• 한국포장학회지
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• 제21권3호
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• pp.91-96
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• 2015

Fruit and vegetables are subjected to complex dynamic stresses in the transportation environment. During a long journey from the production area to customers using parcel delivery service, there is always some degree of vibration present. Vibration inputs are transmitted from the vehicle through the packaging to the fruit. Inside, these cause sustained bouncing of fruits against each other and container wall. These steady state vibration input may cause serous fruit injury, and this damage is particularly severe whenever the fruit inside the package is free to bounce, and is vibrated at its resonance frequency. The determination of the resonance frequencies of the fruit and vegetables may help the packaging designer to determine the proper packaging system providing adequate protection for the fruit, and to understand the complex interaction between the components of fruit when they relate to expected transportation vibration inputs. Instrumentation and technologies are described for determining the vibration response characteristics of the fruits with frequency range 3 to 150 Hz. The resonance frequency of the pear ranged from 53 to 102 Hz and the amplitude at resonance was between 1.08 and 2.48 G. The resonance frequency and amplitude at resonance decreased with the increase of the sample mass, and they were slightly affected by mechanical properties such as bioyield deformation and rupture deformation. Regression analysis was performed among the relatively high correlated parameters from the results of correlation coefficient analysis.

• 한국기계가공학회지
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• 제19권7호
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• pp.89-97
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• 2020

Container vessels continue to grow in size, led by global shipowner. Large ships can be loaded more cargo at a time, reducing the cost of transportation per teu. this eventually leads to economies of sale, in which the production cost per unit decreases with increasing output. in accordance with the 70th Convention of the Marine Environment Protection Committee of the International Maritime Organization, as of January 1, 2020, MARPOL Annex VI Regulation 14.1.3 will be effective. All vessels must be meet these criteria to reduce Sox emissions and reduce NOx emissions by reducing the content of manned sulfur oxides from 3.5% to less than 0.5%, otherwise IACS Member States Entry to the port is denied. in order to do that need to LNG storage tank. in this study characteristic of the material after line heating (600℃,700℃,800℃,900℃) of 9% Ni steel used in the manufacture of LNG fuel tank of ship were verified using by mechanical test. In the heating method by line heating. The initial properties of steel are changed by variables such as temperature, time, speed. The experimental data of line heating presented in this paper confirmed that the initial change of 9% Ni steel could be minimized.

• Parasites, Hosts and Diseases
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• 제35권3호
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• pp.149-154
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• 1997

저장 곡류 해충으로 알려져 있는 긴털가루진드기(rophnwpkescentios)가 우리 나라 가옥 내 집먼지 서식 진드기류 중 제 3의 우점종으로 밝혀짐에 따라 알레르기성 질환을 야기하는 원인 항원으로 작용할 가능성이 높아져 연구의 대상이 되고 있다. 본 연구에서는 진단, 치료 및 면역학 적 연구에 필요한 다량의 항원을 공급하기 위하여 대량 사육방법의 개발을 시도하여 다음과 같은 결과를 얻었다. 긴털가루진드기를 대량 사육하는데 가장 적합한 사육배지로는 실험동물사료 분말 로 사육 10주 후 1,251.5배의 개체 증가를 보였고 효소분말과 실험동물 사료분말의 혼합배지 (1 : 1)에서도 사육 10주 후 1.203.1배의 개체 증가를 보여 거의 같은 성적을 보였다. 사육조건으 로 가장 적합한 온도와 상대습도는 $25^{\circ}C$. 64% RH로서 9주 후 960배로 가장 높은 증식결과를 보였고, $^25{\circ}C$와 75% RH에서도 935.4배의 개체 증가로 거의 동일한 결과를 나타냈다 사육용기 표면적을 $79{\;}cm^2,{\;}154{\;}cm^2{\;}및{\;}227{\;}cm^2$로 사육 비교한 결과 각각 860.8배. 924.6배 및 1,250.8 배의 개체 증가를 보여 현저한 차이는 보이지 않았다.

• 공업화학
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• 제28권5호
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• pp.513-520
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• 2017

폐유리의 친환경적 재사용을 목적으로 발포유리를 제조하는데 있어서 에너지 소모가 상대적으로 적은 '인덕션 가열법'을 적용한 결과 제조온도를 $300^{\circ}C$ 이하로 낮출 수 있으며 고가의 각종 무기산화제를 첨가하지 않고, 인체에 무해한 폐유리가루, 물유리와 소량의 계면활성제와 기포안정제만을 사용하여 발포유리를 제조할 수 있었다. 본 실험의 실험범위에서 확인한 최적의 조건은 유리가루 110 g, 물유리 80 g, 계면활성제 3 g과 안정제 0.2 g을 사용하여 특수 제작한 철제용기($100mm{\times}100mm{\times}20mm$)를 이용하여 인덕션 가열장치에서 비등시켜 4 min간 가열 후 11 min 증발, 건조시킨 경우, 제조한 발포유리의 이때 밀도는 $0.85g/cm^3$, 열전도도 $0.052W/h{\cdot}K$, 압축 강도도 $50kg/cm^2$ 이상으로 분석되었다.

• 농업과학연구
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• 제47권3호
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• pp.633-644
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• 2020

Rice paper is an element of Vietnamese cuisine that can be used to wrap vegetables and meat. Rice and starch are the main ingredients of rice paper and their mixing ratio is important for quality control. In a commercial factory, assessment of food safety and quantitative supply is a challenging issue. A rapid and non-destructive monitoring system is therefore necessary in commercial production systems to ensure the food safety of rice and starch flour for the rice paper wrap. In this study, fluorescence hyperspectral imaging technology was applied to classify grain flours. Using the 3D hyper cube of fluorescence hyperspectral imaging (fHSI, 420 - 730 nm), spectral and spatial data and chemometric methods were applied to detect and classify flours. Eight flours (rice: 4, starch: 4) were prepared and hyperspectral images were acquired in a 5 (L) × 5 (W) × 1.5 (H) cm container. Linear discriminant analysis (LDA), partial least square discriminant analysis (PLSDA), support vector machine (SVM), classification and regression tree (CART), and random forest (RF) with a few preprocessing methods (multivariate scatter correction [MSC], 1^st and 2^nd derivative and moving average) were applied to classify grain flours and the accuracy was compared using a confusion matrix (accuracy and kappa coefficient). LDA with moving average showed the highest accuracy at A = 0.9362 (K = 0.9270). 1D convolutional neural network (CNN) demonstrated a classification result of A = 0.94 and showed improved classification results between mimyeon flour (MF)1 and MF2 of 0.72 and 0.87, respectively. In this study, the potential of non-destructive detection and classification of grain flours using fHSI technology and machine learning methods was demonstrated.

• 디지털융복합연구
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• 제17권4호
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• pp.65-73
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• 2019

연구는 부채비율을 종속변수로 하고 ROE(자기자본 이익률), 매출액, 유동비율, 자본총계, 운임지수인 SCFI(Shanghai Containerized Freight Index)를 독립변수로 하여 패널회귀분석을 실시하였다. GLS 분석결과, 유동비율의 경우 부채비율에 부(-)의 영향을 끼쳤고, 매출액의 경우 부채비율에 정(+)의 영향을 끼쳤다. 또한 자본총계는 부채비율에 부(-)의 영향을 미쳤다. 하지만 ROE의 경우 가설과는 다르게 부채비율에는 부(-)의 영향을 끼쳤고, SCFI지수는 유의미하지 않았다. 본 연구의 시사점으로 글로벌 선사의 부채비율이 높아질수록 글로벌 선사가 규모의 경제를 달성해 매출이 증가한 것을 확인했다. 하지만 타인자본 투입을 통한 규모의 경제실현은 매출액 증가에는 도움은 되지만, 당기순이익에는 영향을 미치지 못함을 확인하였다. 선사는 영업력을 확대하고 대형 컨테이너선을 확보하는 등의 화주 신뢰성을 확보하는 전략에 병행해야 한다. 향후 연구에서는 환율, 세계 경제 성장률, 제조업 생산지수 등을 고려한 분석이 필요하다.

• 식품과학과 산업
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• 제50권2호
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• pp.12-26
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• 2017

Processing steps such as washing and cutting, involved in preparing fresh-cut produce causes tissue damage, leading to rapid quality deterioration. Major defects of fresh-cut produce are discoloration, softening, off-odor development, and microbial growth. Packaging of fresh-cut produce has been changed to reduce these quality problems. Flexible packaging film is widely used to pack fresh-cut produce. Vacuum packaging was the popular packaging method in the beginning of fresh-cut industry in Korea. Vacuum packaging creates high $CO_2$ and low $O_2$ levels to control browning of fresh-cut produce. However, these conditions induce some visual defects and off-odor development. Discoloration problem was also found when fresh-cut produce was packaged with conventional packaging film or plastic tray. Modified atmosphere (MA) packaging is effective for prolonging shelf-life of fresh-cut produce by decreasing $O_2$ and increasing $CO_2$ concentration in the package. Retail MA packaging using different oxygen transmission rate (OTR) film and micro-perforated film has started to be applied to fresh-cut produce in Korea. Proper MA package design that provides optimum range of $O_2$ and $CO_2$ partial pressures is one of the major challenges in the industry. An initial package flushing with $N_2$ or an low $O_2$/high $CO_2$ atmosphere is also used to more rapidly establish steady-state MA condition. Film OTR and $O_2$ flushing affects the fermentative volatile production, off-odor development, electrolyte leakage, discoloration, $CO_2$ injury, microbial population of fresh-cut produce. There is also a demand for convenient packaging to attract consumers. Rigid fresh-cut produce container for retail market has increased since the packaging provides excellent protection from physical damage during transport. Rigid tray used as actual serving vessel for the consumer is increasing in Korea. The tray with flexible lid to wrap or seal fresh-cut produce is more and more gaining popularity. Further practical technology to control quality change and microbial growth for each fresh-cut product has been studied since various fresh-cut items were required. The fresh-cut industry also focuses on searching for more convenient and environmentally friendly packaging.

• 한국산업융합학회 논문집
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• 제26권1호
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• pp.95-103
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• 2023

The domestic remanufacturing industry is concentrated in auto parts, so it is necessary to expand into various industries. In the domestic aluminum industry, the extrusion process accounts for more than 40% of the total, but the old and management of the extrusion equipment is not done properly. In particular, the extruder has a structure in which equipment is not replaced until major parts are damaged or worn, so there are problems such as lower process precision, productivity and production efficiency compared to new equipment, and high maintenance costs. In this study, the old extruder was remanufactured for major high-risk parts through Failure Mode and Effect Analysis(FMEA), and the process level and performance of the extruder were evaluated before and after remanufacturing. Compared to the existing extruder, the standard deviation of the remanufacture extruder was reduced by 93.5%, 57.9%, and 70.0%, respectively, in major process control items such as container temperature, billet temperature, and ram speed, keeping performance constant. In addition, it was possible to produce products with complex shapes that could not be produced before due to problems such as dimensional deviation within tolerances. In this study, remanufacturing guidelines were presented by analyzing the effect of failure modes of the old extruder, and the performance improvement of the extruder was confirmed.