• Journal of the Korean Society of Tobacco Science
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• v.12 no.2
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• pp.59-65
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• 1990

In order to predict the shelf-life of cigarettes packaged in typical flexible film under conditions of various temperature, relative humidity and sealing degree, a computer iterative technique was used. Although there were some significant differences at initial equilibrium relative humidity(55%), the experimental results agree fairly well with predictions following the student's t test($\alpha$=0.01) in most cases. Essentially, the higher the storage temperature, the shorter the shelf-life of the cigarette product. The bigger the differences from the initial equilibrium relative humidity, the shorter the storage period of the cigarette. Moisture transfer through the film at relatively high temperature gave higher confidence. The sealing degree, one of the storage parameters, appeared to be a major influencing factor to shelf-life. Slopes($\beta$) of the temp., sealing degree and %rh of the dependent variable to shelf life were 0.49, -0.39 and -0, 28 respectively, when analysed by multiple regression of SPSS software. Below 600m1/min sealing decree of the packed cigarette through the sealing Position at 30mmH20 differential pressure, the shelf-life could be increased by more than six months.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.628-633
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• 2020

This paper presents an analysis of the shelf-life management program of the long-term storage one-shot system. The one-shot system is mainly maintained with long-term storage or non-operating status and is operated once at execution of the mission. The function corresponding to one-shot is mainly operated through a shelf-life item such as an explosive. The performance and characteristics of shelf-life item are subject to change as the storage period passes. Therefore, shelf-life management for maintaining good condition is very important during long-term storage, and criteria for management is necessary. We present a method for optimizing shelf-life extension by comparing criteria for management with current reliability. Next, the shelf-life evaluation schedule was decided by utilizing the reliability function of exponential distribution and Weibull distribution. Continuously accumulated test data from the shelf-life evaluation were analyzed, and the parameter of distribution was updated. The extension or expiration of shelf-life was selected by monitoring changes in reliability. In addition, we confirmed the applicability of the presented shelf-life management program by applying ASRP test data of the one-shot system K000 fuse.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.6
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• pp.43-52
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• 2022

Operational reliability of the single-use turbo engine for guided weapons must be guaranteed even after long-term storage. Rolling element bearings have a great influence on the operational reliability of the turbo engine, however changes in micro dimensions of bearings by an oxide layers on rolling elements and raceways may cause failures after long-term storage. In this study, changes in dimensions of bearings were measured and roughness of rolling elements was used for estimating the storage life. Storage life estimation was performed via two kinds of methods, Weibayes method and random sample generation method. The results of two methods were compared and their characteristics were analyzed. This study will contribute to establish an efficient maintenance schedule for the single-use turbo engine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3633-3642
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• 2015

Single-base propellants contain a single energetic component: nitrocellulose. Accurate predictions of propellant shelf-life should result in cost savings in terms of human and material resources. This study derived an optimized kinetic model reaction order that described stabilizer consumption and estimated propellant shelf-life. High temperature accelerated aging tests gave an optimum reaction order value of 1.15481, from which the minimum standard error of a linear regression estimate of 16.284 was obtained. At normal storage temperature of $21-30^{\circ}C$, propellants should have a safe shelf-life of 140 years, and a minimum of 35 years. It is necessary to consider the temperature range in ammunition storage areas to predict propellant shelf-life more accurately.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.154-156
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• 2017

Constant variance of degradation data over time has been generally assumed to estimate storage lifetime using destructive, accelerated degradation data over time. However, performance data of ammunitions deteriorate over time, and the standard deviation would tend to increase over time. This paper shows storage lifetime comparison results for constant variance and time-variant variance assumptions of degradation data over time, and proposes that time-variant variance assumption should be considered to increase accuracy in lifetime estimation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.291-300
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• 2020

The cartridges used for illuminating a desired point or area are virtually limited in tests and evaluations because of limitations, such as noise during launch, the possibility of fires caused by illuminant charge, and the annual testable quantity. Therefore, to solve these problems, a ground fixed test, which replaces the firing test, or an evaluation method to perform limited tests, can be applied more efficiently. In this paper, the results of an 81mm illuminating cartridge, KM series performed in 2019 were analyzed comprehensively to identify the trends in reliability and quality characteristics and to estimate the shelf life. The shelf life was estimated to be at least 10 years based on the time when the lower confidence level reached 80% at a confidence level of 90%. Considering only major defects, the shelf life can be estimated to be approximately 23 years. On the other hand, the shelf life was estimated to be approximately 11 to 15 years and 25 to 28 years according to the effective illuminating time. Finally, an assessment plan of illuminating cartridges for the mortars was also presented as an improvement plan for an assessment method in the future.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.762-764
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• 1999

This experiment was conducted to investigate the effect of pretreatments and storage conditions on quality and vase life of cut 'Red Sandra' rose (Rosa hybrida L.). 'Red Sandra' rose flowers were harvested and pulsed with distilled water, 0.2% RVB or 200ppm aluminum sulfate+3% sucrose+50ppm $AgNO_3$+0.1mM ethionine for 22 hours and then stored in wet or dry condition for 12, 24, 48 hours at low or room temperature. Pulsing with aluminum sulfate+sucrose+$AgNO_3$+ethionine delayed bent-neck, increased solution absorption and flower diameter, and prolonged vase life rather than pulsing with distilled water or RVB. Storage in wet condition or low temperature also delayed bent-neck, increased solution absorption and flower diameter, and prolonged vase life compared with storage in dry or room temperature condition. As the storage hours prolonged, solution absorption, flower diameter, and vase life were decreased especially pulsing with distilled water. Pulsing with aluminum sulfate+sucrose+$AgNO_3$+ethionine prolonged vase life compared to pulsing with distilled water or RVB regardless of storage conditions and shipping hours.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.83-84
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• 2000

식품저장의 목적은 수확한 식량이나 가공식품의 관능적 품질과 영양가의 손실 속도를 줄이고 유해 미생물의 증식 가능성을 배제하는 데 있다. 그러나 어떠한 저장 방법을 써도 관능적 품질의 손상과 영양가의 손실을 완전히 정지시킬 수는 없다. 즉 모든 저장식품은 시간의 경과에 따라 언젠가는 먹을 수 없을 정도로 변하게 되어 있으며 주어진 조건에서 제품이 일정수준의 품질을 유지할 수 있는 기간을 곧 저장 수명 또는 품질수명(shelf-life)이라고 정의할 수 있다. (중략)

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.359-360
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• 2020

리튬 이온 배터리가 전기 자동차의 주 동력원으로 사용됨에 따라 배터리의 잔존 수명 예측기술의 중요성이 부각되고 있다. 사용 환경에 적합한 잔존 수명 예측을 위해 전기 자동차의 주행 환경을 모사하여 충전 및 방전이 빈번하게 나타나는 UDDS 프로파일에서 범용적으로 사용할 수 있는 수명 인자를 선정하는 것이 필수적이다. 배터리의 잔존 용량과 가장 상관도가 높은 수명 인자를 선정함으로써, 인공지능 기반 예측 알고리즘의 정확도 향상을 기대 할 수 있으며, 태양광 ESS와 같은 상이한 특성의 어플리케이션에도 범용적인 적용이 가능하다.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.252-260
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• 2012

This study was carried out to compare the storability in MA storage and quality of paprika fruits among 9 cultivars grown in 2011 and 12 cultivars in 2012. 'Mosanto 7044' was the most proper cultivar in red-type paprika has grown in 2011 for MA storage, because it showed relatively higher fruit weight, firmness, soluble solid content, and the lowest ethylene production rate, as well as the second longest shelf life. 'Stayer' was suitable cultivar in yellow-type paprika cultivated in 2011, because it showed higher firmness, soluble solid content and lower ethylene production rate than other cultivars. 'Nagano' was the most proper cultivar in red-type paprika has grown in 2012 for MA storage. Because it showed relatively higher fruit weight, firmness, flesh thickness and the lowest ethylene production rate and decay ratio, although the shelf life of 'Nagano' was the third longest (28 days). 'Freestar' was the excellent cultivar in yellow-type paprika cultivated in 2012, because it showed higher firmness, vitamin C content and lower respiration rate than other cultivars and the longest shelf life of 26 days. The shelf life had a high correlationship with ethylene production rate (r = -0.5504), and soluble solid (r = 0.6112), as comparing with the shelf life and the fruit characteristics of 21 cultivars paprika has grown in 2011 and 2012.