• Title/Summary/Keyword: Field aged

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Lifetime prediction for interfacial adhesion of Carbon/Cork composites with an accelerated aging test

  • Lee, Hyung Sik;Chung, Sang Ki;Kim, Hyung Gean;Park, Byeong Yeol;Won, Jong Sung;Lee, Seung Goo
    • Carbon letters
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    • v.28
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    • pp.9-15
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    • 2018
  • In the aerospace field, Carbon/Cork composites have been used for rocket propulsion systems as a light weight structural component with a high bending stiffness and high thermal insulation properties. For the fabrication of a carbon composite with a heat insulation cork part, the bonding properties between them are very important to determine the service life of the Carbon/Cork composite structure. In this study, the changes in the interfacial adhesion and mechanical properties of Carbon/Cork composites under accelerated aging conditions were investigated. The accelerated aging experiments were performed with different temperatures and humidity conditions. The properties of the aged Carbon/Cork composites were evaluated mainly with the interfacial strength. Finally, the lifetime prediction of the Carbon/Cork composites was performed with the long-term property data under accelerated conditions.

Geriatric Foot Problems and Related Factors in Two Provinces of Korea (일부 지역 노인 족부 건강 문제와 영향 요인)

  • Kim, Shin-Mi;Ahn, Jae-Hong;Choi, Sook-Hee;Lee, Yun-Jung
    • Journal of Korean Academy of Nursing
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    • v.40 no.2
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    • pp.161-171
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    • 2010
  • Purpose: The purpose of the study was to identify the prevalence, risk factors and clinical meanings of geriatric foot problems and to suggest implications for the future. Methods: One hundred eighty nine elderly aged 60 and over from institution as well as community were investigated for their foot conditions by means of a questionnaire including general characteristics, self care capacity, risk factors, foot problem checklist, X-ray, podoscopy and foot scan. Descriptive statistics and $\chi^2$-test was performed as appropriate utilizing SPSS version 14. Less than .05 of p-value was adopted as statistical significance level. Results: All subjects had at least one kind of foot problem and the most prevalent ones were nail problems, foot deformities in order. Prevalence of foot pain and edema was relatively low. Conclusion: Foot problem in elderly is prevalent and geriatric foot is expected to emerge as one of the most important problems in the geriatric field. Therefore strategies to deal with geriatric foot should be developed and practiced for better quality of life in later life.

Classification of Silver Farming Types and Investigation of Proper Crop for Silver Farmers (실버농업의 유형분류 및 적합작목 탐색)

  • Kang, Kyeong-Ha;Yoon, Soon-Duck;Kang, Jin-Ku
    • Journal of Agricultural Extension & Community Development
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    • v.14 no.2
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    • pp.301-328
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    • 2007
  • The purposes of this study were to classify the silver farming types and to investigate proper crops for silver farmers. Data were collected from 408 farmers returned from the urban area. Descriptive statistics were employed using SPSS/PC windows program. After then, researchers discussed the silver farming patterns and their proper crops, and tried to analyze the silver farming model. Major results were as follows: The farming aims of retirees, urban residents as well as farmers returned from the urban area were various from hobby/ leisure to income generating activities. Fourteen types of silver farming were classified by farming aim and residential area of retirees. Retirees in the hobby/leisure-oriented silver farming type can select and enjoy the various plants, animals, and insects as well as crops due to their small scale. Silver farmers in the self-sufficiency type may select crops for their food. Income-oriented silver farmers may have difficulties in choosing the proper crop. They must consider their income needs, health status and field location. Profit-oriented silver farmers with venture mind can have some business opportunities in the agricultural sectors in spite of severe competition. As the aged silver farmers have poor health, they must keep work safety rules, use the proper work-aids, and utilize the labor-saving farming system.

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Tracking Performance Test of Polymer Insulator with Salt Solution which is added Surface Active Agent (계면활성제가 첨가된 염수용액에 따른 폴리머 애자의 트래킹 성능 평가)

  • Cho, Han-Goo;Han, Dong-Hee;Lee, Un-Yong;Lim, Kee-Joe;Choi, In-Hyuk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.1121-1124
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    • 2004
  • Aging test to estimate life property of polymer insulator is executed through several international standard such as IEC 61109 and CEA tracking wheel test, but is not getting clear conclusion yet. There are two methods in the diagnosis method of polymer insulator such as off-line and on-line. The diagnosis methods in off-line are external condition analysis by the eye, contaminant analysis on surface, surface analysis, pollution withstand voltage test, power frequency flashover voltage test, lightning impulse flashover test, tensile fracture load test and flexural load test. The diagnosis methods in off-line most are the method for virgin and last aged sample. However, the diagnosis method in on-line is method that can be evaluate sample state as progressing continuously aging test in beginning, The diagnosis method in on-line is arranged as following: leakage current measurement, electric field, surface state investigation, thermal image, emitting light measurement and then so. In this paper, the tracking performance of polymer insulator with salt solution which is added surface active agent. The diagnosis of insulator sample has been analyzed by leakage current and visual examination.

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A Study on Implementation of Risk Based Inspection Procedures to a Petrochemical Plant (RBI 절차의 석유화학 플랜트 적용에 관한 연구)

  • Song, Jung-Soo;Shim, Sang-Hoon;Kim, Ji-Yoon;Yoon, Kee-Bong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.3
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    • pp.416-423
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    • 2003
  • During the last ten years, the need has been increased for reducing maintenance cost for aged equipments and ensuring safety, efficiency and profitability of petrochemical and refinery plants. RBI (Risk Based Inspection) methodology is one of the most promising technologies satisfying the need in the field of integrity management. In this study, a user-friendly software, realRBl for RBI based on the API 581 code was developed. This software has modules for evaluating qualitative and semi-quantitative risk level, analyzing quantitative risks using the potential consequences of a failure of the pressure boundary, and assessing the likelihood of failure. A quantitative analysis was performed for 16 columns in a domestic NCC (Naphtha Cracking Center) plant whose operating time reaches about 12 years. Each column was considered as two equipment parts by dividing into top and bottom. Generic column failure frequencies were adjusted based on likelihood data. After determining release rate, release duration and release mass for each failure scenario, flammable/explosive and toxic consequences were assessed. Current risks for 32 equipment parts were evaluated and risk based prioritization were determined as a final result.

Development of Horizontal Locomotion Robot using Rail Mechanism for H-beam Structure (H-빔 구조물에서의 레일을 이용한 수평주행로봇 개발)

  • Kim, Jong Heon;Jeon, Minseok;Jeon, Kyungtae;Lee, Sang Hoon;Hong, Daehie
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.4
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    • pp.421-426
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    • 2013
  • Nowadays in building construction field, workers become aged and avoid dirty, difficult, and dangerous work. Above all, a person who is in charge of beam assembling work in high and narrow space just relies on safety belt. So these workers should be highly trained. This paper deals with a new locomotion robot that can take this in charge, which will be able to provide less labor costs, less time to build a building and safer environments for workers. The geometric features of steel structure in building construction were carefully analyzed and developed a locomotion mechanism optimized to it. The robot was designed to be rugged, strong, and fast rather than having excessive mobility. Feasibility of the developed robot was verified through experiments.

Analysis of Lethality in Echinococcal Disease

  • Khachatryan, Anna S.
    • Parasites, Hosts and Diseases
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    • v.55 no.5
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    • pp.549-553
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    • 2017
  • The information on mortality from echinococcosis is important not only for a better understanding of the severity of the disease, but also for evaluating the effectiveness of public health interventions. The aim of this research was to study the causes of mortality from echinococcosis. We have collected and analyzed the materials of 1,470 patients in 10 age - groups in the Republic of Armenia (from 2000 to 2016). To find out the causes of mortality from echinococcosis, we have analyzed the medical histories and protocols of postmortem examinations of 19 deaths from echinococcosis and 17 deaths due to other indirect causes not associated with the parasite. The average annual death rate from echinococcosis is 0.007 per 10,000 population, and the mortality is 1.29 (per 100 patients). The highest mortality occurs in people aged 70-79. Mortality from echinococcosis is also recorded among the unoperated children. The rupture of the parasitic cyst and hepatic insufficiency are major among the direct causes of mortality. Sometimes the hydatid cysts unrecognized during the life were first diagnosed at autopsy. Insufficient qualification of doctors in the field of helminthology, as well as the latent course of the disease or manifestation of minor symptoms in echinococcosis over a long period often led to medical errors. Further decline in mortality can be achieved by early diagnosis, timely hospitalization and treatment before the development of severe complications worsening the prognosis and outcomes of surgical intervention.

Fundamental Investigation of Functional Property of Concrete Mixed with Functional Materials

  • Lee, Jong-Chan;Lee, Moon-Hwan;Lee, Sae-Hyun;Park, Young-Sin;Park, Jae-Myung
    • International Journal of Concrete Structures and Materials
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    • v.18 no.3E
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    • pp.165-171
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    • 2006
  • Environment-friendly materials are increasingly used as building construction materials nowadays, and the market share of those is growing. Accordingly, the research and developments in terms of environmental value are progressing steadily now. The main characteristics of environmental products are far-infrared radiation, negative-ion emission, electromagnetic wave shielding, and antimicrobial property. These products are often used in mortar and as spray on the finishing material. Nevertheless, there are hardly any research on the functional properties of concrete, the main material in construction field. Thus, we evaluated such basic properties of concrete as slump, compressive strength and air content while using such functional materials as sericite, wood-pattern sandstone, carbon black and nano-metric silver solution to focus on their functional properties like far-infrared radiation, negative ion emission, electro magnetic wave shielding, and antimicrobial activity in this research. The results indicated that the most useful material in the functional materials was carbon black. Sericite and nano-metric silver solution had a little effect on the functional property. Moreover, although wood-pattern sandstone had very high functional property, it exhibited too low compressive strength to be applied, to concrete as a factory product. Antimicrobial property of nano-metric silver solution in the concrete was not clear demonstrated, but if these specimens were to be aged in $CO_2$ gas for a long time, it might be apparent.

Development of Risk Based Inspection (RBI) Procedures for Optimized Preventive Maintenance (PM) Planning of Energy Plants (에너지플랜트의 최적 예방점검을 위한 위험도기반 설비 관리(RBI) 절차 개발)

  • Choi, Jeong-Woo;Yoon, Kee-Bong
    • Journal of the Korean Institute of Gas
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    • v.15 no.1
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    • pp.74-80
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    • 2011
  • Recently, needs for extending remaining life and integrity of the aged energy plants are increased since the most domestic plants have been operated over 10 years. This need makes RAM (reliability, availability and maintainability) of the plant become more significant. RBI (risk based inspection) is main technology to increase RAM in energy plants. So far RBI has been developed mainly in the field of process plants (chemical/refinery), underground buried pipelines or nuclear power plants. However, the existing RBI procedure is limited mainly to process plants, it need to be extended to the other energy plants such as fossil power plants. In this study, a general RBI procedure for optimized PM (preventive maintenance) is proposed for various energy plants.

Performance Analysis of Neural Network on Determining The Optimal Stand Management Regimes (임분의 적정 시업체계분석을 위한 Neural Network 기법의 적용성 검토)

  • Chung, Joo Sang;Roise, Joseph P.
    • Journal of Korean Society of Forest Science
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    • v.84 no.1
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    • pp.63-70
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    • 1995
  • This paper discusses applications of neural network to stand stocking control problems. The scope of this research was to develop a neural network model for finding optimal stand management regimes and examining the performance of the model for field application. Performance was analyzed in consideration of the number of training examples and structural aspects of neural network. Research on network performance was based on extensive optimization studies for pure longleaf pine(Pinus palustris) stands. For experimental purposes. an existing nonlinear even-aged stand optimization model with a whole-stand growth and yield simulator was used to generate data samples required for the performance analysis.

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