• Title/Summary/Keyword: Life Conditions

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Development of a Tool Life Prediction Program for Increasing Reliability of Cutting Tools (공구의 신뢰성 향상을 위한 수명 예측 프로그램 개발)

  • Kim Bong-Suk;Kang Tae-Han;Kang Jae-Hun;Song Jun-Yeob;Lee Soo-Hun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.3
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    • pp.1-7
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    • 2005
  • The prediction for tool life is one of the most important factors for increasing reliability, stability, and productivity of manufacturing system. This paper deals with a tool life prediction method in view of reliability assessment for cutting tools. In this study, flank wear was focused among multi-factors deciding the tool wear state. First, tool life was predicted by correlation between flank wear and cutting time, based on the extended Taylor tool life equation of turning, including parameters of cutting speed, feed rate, and cutting depth. Second, each of cutting conditions of end-milling was equivalently converted to apply ball end-mill data to the extended Taylor equation. The web-based prediction program for tool life was developed as one of reliability assessment programs for machine tools.

Fatigue Life Evaluation of the Plastic Gear (플라스틱 기어의 피로수명 평가 및 수명 예측)

  • Chong Tae Hyong;Kang Sung Kyu;Ha Young Wook
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2005.05a
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    • pp.239-245
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    • 2005
  • Through the fatigue test of plastic gears using polyacetal polymer, this research aims at providing basic data for not only specifying operation conditions of plastic gears, but also designing dimensions of plastic gears with giving fatigue life and the estimated equation of fatigue life of plastic gears. That is, from the fatigue life curves, the estimated equation of fatigue life of plastic gears is taken out. For the estimated equation of fatigue life of plastic gears, this research provides two test methods; one is preserving non-limited temperature of tooth flank, the other is preserving limited temperature of tooth flank. As results, how the temperature of tooth flank affects the fatigue life is shown. In addition, based on the endurance limit, the essential factors of the unit load and K-factor are determined, which are needed in the design of gear by bending strength and surface durability.

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ClC Chloride Channels in Gram-Negative Bacteria and Its Role in the Acid Resistance Systems

  • Minjeong Kim;Nakjun Choi;Eunna Choi;Eun-Jin Lee
    • Journal of Microbiology and Biotechnology
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    • v.33 no.7
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    • pp.857-863
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    • 2023
  • Pathogenic bacteria that colonize the human intestinal tract have evolved strategies to overcome acidic conditions when they pass through the gastrointestinal tract. Amino acid-mediated acid resistance systems are effective survival strategies in a stomach that is full of amino acid substrate. The amino acid antiporter, amino acid decarboxylase, and ClC chloride antiporter are all engaged in these systems, and each one plays a role in protecting against or adapting to the acidic environment. The ClC chloride antiporter, a member of the ClC channel family, eliminates negatively charged intracellular chloride ions to avoid inner membrane hyperpolarization as an electrical shunt of the acid resistance system. In this review, we will discuss the structure and function of the prokaryotic ClC chloride antiporter of amino acid-mediated acid resistance system.

A Grounded Theory Approach to the Comfort Experience of Hospitalized Patients (입원대상자의 안위경험에 대한 근거이론적 접근)

  • 김경희;김금순;강규숙;강현숙;김원옥;백훈정;원종순;임난영;정인숙
    • Journal of Korean Academy of Nursing
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    • v.30 no.3
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    • pp.750-763
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    • 2000
  • This study is based on grounded theory methodology by Strauss & Corbin(1998). Ten hospitalized subjects were interviewed for data collection. In the process of data analysis, 'acceptance' is found to be the causal condition, while 'health professionals' skillfulness', 'ward environment', 'history of hospitalization', and 'general conditions' were identified as context, 'felling of relief' as the core phenomenon, 'self-efficacy', 'support of others', and 'life style' as the intermediate situation, 'passive reaction', 'alternative reaction' and 'active reaction' as the strategy and 'stabilization', 'satisfaction', 'hope' and 'carrying out' as consequences. 'Feeling of relief' is found to go through the three stages of recognition-generation-maintenance after the five different patterns. 1) In case the health professionals are skillful, the ward environment is favorable, the general conditions of the patients improved and as a result the feeling of relief is strong, during the first hospitalization, the self-efficacy of the subjects tends to be strong. They proceed toward the goal set for themselves with a renewed hope and active or alternative reaction toward the feeling of relief. 2) The subjects tend to proceed toward the goal set for themselves with a renewed hope and active and alternative reaction toward the feeling of relief in case health professionals are skillful, the ward environment is favorable the general conditions of the subjects improved, self-efficacy is strong, and lifestyle is autonomous, during the second hospitalization even though support of others is merely superficial. 3) The subjects tend to stabilize, and satisfy themselves with the given situation with passive and alternative reaction to the feeling of relief in case health professionals are skillful and the ward environment is favorable but the general conditions worsened and accordingly the feeling of relief, is weak and life style is dependent during the second hospitalization although the subjects' self-efficacy is strong and support of others is specific. 4) The subjects tend to stabilize and satisfy themselves with the given situation with passive and alternative reaction to the feeling of relief in case health professionals are unskillful the ward environment is unfavorable, the general conditions improved, support of others is specific but life style is dependent and self-efficacy is weak during the first hospitalization. 5) The subjects tend to stabilize and satisfy themselves with the given situation in case health professionals are unskillful the ward environment is unfavorable but the general conditions improved support of others is specific and as a result self-efficacy is strong but life style is dependent.

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