• Title/Summary/Keyword: runaway test

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A Study on Developing Safety and Performance Assessment Guideline for Electronic Warm-Acupuncture Apparatus (전기식 온침기에 대한 안전성 및 성능평가 가이드라인 개발 연구)

  • Hansol Jang;U-Ryeong Chung;Jeong-Hyun Moon;Seong-Kyeong Choi;Won-Suk Sung;Min-Seop Hwang;Seung-Deok Lee;Kyung-Ho Kim;Jong-Hwa Yoon;Eun-Jung Kim
    • The Journal of Korean Medicine
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    • v.43 no.3
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    • pp.150-163
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    • 2022
  • Objectives: This research aimed to develop a guideline for evaluating safety and performance of electronic warm-acupuncture apparatus. With the development of medical devices like electronic warm-acupuncture apparatus with improved performance, convenience and safety measures compared to traditional warm-acupuncture needling, safety and performance guideline is a necessity. Methods: By referring to existing standards and guidelines of other electronic devices for Korean medicine with heating function, guideline for safety and performance assessment of electronic warm-acupuncture apparatus was drafted Results: The guideline, presents explanation for adequate temperature and settings of the apparatus, and safety measurements providing against thermal runaway situations along with guidelines for the manual. Guideline for detailed test method for the performance of the apparatus such as accuracy of temperature increase and the timer, and safety unit was also provided. The test items and suggested test methods for the requirements of biological, electrical and electromagnetic safety were referred to Korean approval documents of ministry of Food and Drug Safety. Conclusion: We proposed the relevant items to verify performance and safety of warm-acupuncture apparatus to assure patient safety and improve the quality of currently developing devices for application in clinical field.

Optimization of the Backfill Materials for Underground Power Cables considering Thermal Resistivity Characteristics (II) (열저항 특성을 고려한 지중송전관로 되메움재의 최적화(II))

  • Kim, You-Seong;Cho, Dae-Seong;Park, Young-Jun
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.4
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    • pp.123-130
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    • 2011
  • In the precedent study it was presented that the comparison of thermal resistivity using various backfill materials including river sand regarding water content, dry unit weight and particle size distribution. Based on the precedent study, this study focused on developing the optimized backfill material that would improve the power transfer capability and minimize the thermal runaway due to an increase of power transmission capacity of underground power cables. When raw materials, such as river sand, recycled sand, crush rock and stone powder, are used for a backfill material, they has not efficient thermal resistivity around underground power cables. Thus, laboratory tests are performed by mixing Fly-ash, slag and floc with them, and then it is found that the optimized backfill material are required proper water content and maximum density. Through various experimental test, when coarse material, crush rock, is mixed with recycled sand, stone powder, slag or floc for a dense material, the thermal resistivity of it has $50^{\circ}C$-cm/Watt at optimum moisture content, and the increase of thermal resistivity does not happen in dry condition. The result of experiments approach the optimization of the backfill materials for underground power cables.

Characterization of aluminized RDX for chemical propulsion

  • Yoh, Jai-ick;Kim, Yoocheon;Kim, Bohoon;Kim, Minsung;Lee, Kyung-Cheol;Park, Jungsu;Yang, Seungho;Park, Honglae
    • International Journal of Aeronautical and Space Sciences
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    • v.16 no.3
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    • pp.418-424
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    • 2015
  • The chemical response of energetic materials is analyzed in terms of 1) the thermal decomposition under the thermal stimulus and 2) the reactive flow upon the mechanical impact, both of which give rise to an exothermic thermal runaway or an explosion. The present study aims at building a set of chemical kinetics that can precisely model both thermal and impact initiation of a heavily aluminized cyclotrimethylene-trinitramine (RDX) which contains 35% of aluminum. For a thermal decomposition model, the differential scanning calorimetry (DSC) measurement is used together with the Friedman isoconversional method for defining the frequency factor and activation energy in the form of Arrhenius rate law that are extracted from the evolution of product mass fraction. As for modelling the impact response, a series of unconfined rate stick data are used to construct the size effect curve which represents the relationship between detonation velocity and inverse radius of the sample. For validation of the modeled results, a cook-off test and a pressure chamber test are used to compare the predicted chemical response of the aluminized RDX that is either thermally or mechanically loaded.

Study on the Development of Reading Psychology Coaching Program for Female Teenage Runaways - Focusing on the Application of Adler's Individual Psychology (여자 가출청소년의 독서심리코칭 프로그램 개발 효과에 관한 연구 - 아들러의 개인심리학 적용을 중심으로 -)

  • Heo, Jeonghee;Cho, Miah
    • Journal of Korean Library and Information Science Society
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    • v.48 no.2
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    • pp.405-428
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    • 2017
  • This paper attempts to develop reading psychology coaching program that applies Adler's individual psychology for female teenage runaways who live in adolescent shelters located in Yongin and Siheung in Korea and examine its effect. For this purpose, the study implemented 120-minute reading psychology coaching program for a total of 12 sessions during the period August 9th in 2016 to October 30th in 2016. For verification of the effects, this study conducted a comparison analysis on the pre and post-hoc test of life style scales and inferiority complex symptom scales, output reports in each session, and writing materials. In the study results, the reading psychology coaching program that applies Adler's individual psychology showed positive effects on female adolescents in shelters.

A Study on the Fire Risk of ESS through Fire Status and Field Investigation (화재현황 및 현장조사를 통한 ESS의 화재 위험성 연구)

  • Park, Kwang-Muk;Kim, Jae-Hyun;Park, Jin-Yeong;Bang, Sun-Bae
    • Fire Science and Engineering
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    • v.32 no.6
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    • pp.91-99
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    • 2018
  • Recently, the spread of ESS in Korea has increased and a fire accident has also occurred. By July 2018, there were a total of 7 cases. All 7 cases were ESS systems consisting of lithium-ion batteries and were burned down. Both the automatic fire extinguisher and the fire department were not able to digest. In this paper, the characteristics of ESS fire are analyzed based on recent ESS fire situation and field investigation, and the cause of fire is divided into environmental, electrical and thermal factors. As a result, it was found that the ESS fire was correlated with the installation environment of the system. In the domestic and overseas lithium ion battery test standard and ESS facility standard survey, the trends and differences of domestic and overseas facilities standards were identified. Based on the fire status and field investigationy, and domestic and overseas facility standard survey, measures were suggested to prevent and prevent the spread of fire in ESS fire.

erratum : A Study on Developing Safety and Performance Assessment Guideline for Electronic Warm-Acupuncture Apparatus (erratum : 전기식 온침기에 대한 안전성 및 성능평가 가이드라인 개발 연구)

  • Hansol Jang;U-Ryeong Chung;Jeong-Hyun Moon;Seong-Kyeong Choi;Won-Suk Sung;Min-Seop Hwang;Seung-Deok Lee;Kyung-Ho Kim;Jong-Hwa Yoon;Eun-Jung Kim
    • The Journal of Korean Medicine
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    • v.44 no.1
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    • pp.128-128
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    • 2023
  • Objectives: This research aimed to develop a guideline for evaluating safety and performance of electronic warm-acupuncture apparatus. With the development of medical devices like electronic warm-acupuncture apparatus with improved performance, convenience and safety measures compared to traditional warm-acupuncture needling, safety and performance guideline is a necessity. Methods: By referring to existing standards and guidelines of other electronic devices for Korean medicine with heating function, guideline for safety and performance assessment of electronic warm-acupuncture apparatus was drafted Results: The guideline, presents explanation for adequate temperature and settings of the apparatus, and safety measurements providing against thermal runaway situations along with guidelines for the manual. Guideline for detailed test method for the performance of the apparatus such as accuracy of temperature increase and the timer, and safety unit was also provided. The test items and suggested test methods for the requirements of biological, electrical and electromagnetic safety were referred to Korean approval documents of ministry of Food and Drug Safety. Conclusion: We proposed the relevant items to verify performance and safety of warm-acupuncture apparatus to assure patient safety and improve the quality of currently developing devices for application in clinical field.

Implementation of Battery Management System for Li-ion Battery Considering Self-energy Balancing (셀프에너지 밸런싱을 고려한 리튬이온전지의 Battery Management System 구현)

  • Kim, Ji-Myung;Lee, Hu-Dong;Tae, Dong-Hyun;Ferreira, Marito;Park, Ji-Hyun;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.3
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    • pp.585-593
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    • 2020
  • Until now, 29 fire accidents have occurred; 22 of them were caused by the interconnection of renewable energy sources that occurred during the rest period after the lithium-ion battery had been fully charged regardless of the seasons. The fire accidents of ESS were attributed to thermal runaway due to the overcharging of a few cells with the phenomenon of self-energy balancing, which is unintentional current flow from cells with a high SOC to the low cells if the SOC condition of each cell connected in parallel is different. Therefore, this paper proposes a novel configuration and operation algorithm of the BMS to prevent the self-energy balancing of ESS and presents a hybrid SOC estimation algorithm. From the test results of the self-energy balancing phenomenon between aging and normal cells based on the proposed algorithm and BMS, it was confirmed the possibility of self-energy balancing, which is unintentional current flow from cells with a high SOC to cells with a low SOC. In addition, the proposed configuration of the BMS is useful and practical to improve the safety of lithium-ion batteries because the BMS can reliably disconnect a parallel connection of the cells if the self-energy balancing current becomes excessively high.