• Title/Summary/Keyword: airtight performance

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Study on the Gas Tight Shut-off Valve of NBC Shelter using Positive Pressure Measurement and Chemical Detection Module (양압측정 및 화학탐지 모듈을 적용한 화생방 방호시설의 가스차단밸브에 관한 연구)

  • Park, Hyoung-Keun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.7
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    • pp.417-422
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    • 2017
  • One of the most frightening aspects of weapons of mass destruction (WMD) is their ability to cause death in very small quantities without being visible to the public. The military authorities are making considerable effort to ensure the survivability of the combatants in the event of NBC(Nuclear, Biological and Chemical) contamination. Therefore, in this study, modules were developed for the measurement of the positive pressure and for the detection of the chemicals used for the control of the various shut-off valves used in an NBC shelter. In addition, a high performance gas tight shut-off valve was developed that can overcome the disadvantages associated with manual manufacturing, such as the occurrence of defective products and high manufacturing cost. By applying the positive pressure measurement and chemical detection modules, this valve was able to be used to control the facility. The developed gas-tight shut-off valve maintained airtight characteristics at a pressure loss of 28[Pa] at the prescribed wind velocity and an internal pressure of 30[kPa]. It is expected to be possible to control the gas-tight shut-off valve through the remote measurement of the positive pressure, thereby ensuring the foreign independence of import substitution and defense related technology in the future. In addition, by installing these valves in all of the intake ports or exhaust ports connected to the outside of the NBC shelter, it is possible to prevent the damage resulting from the rapid inflow of the storm pressure caused by conventional weapons and nuclear explosions, thereby protecting the people and equipment in the shelter.

An Efficient Authentication Mechanism in Mobile-IP Network (Mobile-IP망에서의 효율적인 인증 방안)

  • Chung, Sun-Nie;Chae, Ki-Joon;Jang, Jong-Soo;Sohn, Sung-Won
    • Journal of KIISE:Information Networking
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    • v.28 no.3
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    • pp.321-335
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    • 2001
  • The explosive growth in wireless networking increasingly urges the demand to support mobility within the Internet which is what Mobile-IP aims to provide. Because the transmission of signals through open-air s easy to be attacked, it is important to provide secure transmission for mobile users and make them responsible for what they have done in networks. Although IETF provides a secret-key based security mechanism, those mechanisms suffer from scalability, efficiency and non-repudiation service problem. The proposed mechanism uses public-key based authentication optimizing the performance. It includes non-repudiation service on the side of mobile for airtight security in wireless network. The simulation results show that the proposed authentication reduces the total registration time. It especially minimizes the computation cost on the side of the mobile node and solves the power problem. In practice, the proposed authentication is feasible with reasonable performance and security service in macro mobility that Mobile-IP is intended to solve.

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A Study on the Performance of Ondol with a Ventilation System (환기시스템을 갖춘 온돌 성능에 관한 연구)

  • Jeon, Sung-Taek;Cho, Jin-Pyo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.7
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    • pp.4047-4051
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    • 2014
  • Modern apartment houses are constructed to be relatively airtight with a high heat insulation system to increase the energy efficiency. Such a system has a range of deleterious effects due to the insufficient ventilation. In this study, the ondol system, which is used as a heat source typical of winter in Korea, was set as the default system to evaluate the indoor heat environment according to the ventilation method, the factors of energy reduction by the ventilation system was analyzed. The experimental apparatus was used to simulate the ambient conditions for a certain constant temperature and humidity chamber. The experimental results showed that the supply water temperature higher air volume decreases with increasing supply air temperature in the following order: floor supply/exhaust > total heat exchange supply/exhaust > forced supply/exhaust. Through this study, the applicability of various ventilations could be examined.

A Study on Fire Hazard Analysis and Smoke Flowing for the Semiconductor Manufacturing Process (반도체 제조공정의 연기유동에 관한 연구)

  • Han, Soo-Jin;Kang, Kyung-Sik
    • Journal of the Korea Safety Management & Science
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    • v.9 no.1
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    • pp.197-211
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    • 2007
  • The power of semiconductor, Korea is continuously constructing semiconductor production line for keeping a front-runner status. however, studies and data about potential risks in semiconductor factory are still short. If fire does not initially suppressed, the fire causes a great damage. To decrease fire risk factors, in addition to fire fighting safety equipment, more important thing is how to design and construct fire protection system. The current fire protection codes about semiconductor factory come under functional law, and this law is short of consideration about particularity of factory. The existing prescriptive fire codes depending on experience compose without evident engineering verifications, thus equipments which is created by the current prescriptive fire code may bring about a variety of problems. For example, the design under the current regulation can not cope with the excessive investments, low efficiencies, and the diversifying construction designs and be applied to the quick changes of new technologies. Ergo, an optimal design for fire protection is to equip fire protection arrangements with condition and environment of production field. Manufacturing factory of semiconductors is a windowless airtight space. And for cleanliness, there exists strong flow of cooperation. Therefore, there is a need for fire safety design that meets the characteristic of a clean room. Accordingly, we are to derive smoke flow according to cooperation process within a clean room and construction plan of an optimal sensor system. In this study, in order to confirm the performance of proposed smoke-exhaust equipment and suggest efficient smoke exhaust device when there is a fire of 1MW of methane in the clean room of company H, we have implemented fire simulation using fluid dynamics computation.

Analysis of Ventilation Impact in Multi-Family Residential Building Utilizing TOPSIS Method (다기준 의사결정방법을 이용한 공동주택 내 환기장치 종류별 효과분석)

  • Park, Kyung-Yong;Kim, Gil-Tae;Kim, Tae-Min;Ji, Won-Gil;Kwag, Byung-Chang
    • Land and Housing Review
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    • v.13 no.3
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    • pp.107-113
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    • 2022
  • With increasing airtight building construction aimed at reducing energy consumption, indoor relative humidity is increasing which can lead to condensation and moisture damage in multi-family residential buildings. This has led to increased implementation of mechanical ventilation to control indoor moisture. However mechanical ventilation systems consume additional energy and generate noise. As this leads to occupant discomfort, it is necessary to select a ventilation system that addresses the energy and noise issues. This research measured the ventilation performance, energy consumption, and noise level of mechanical ventilation devices in multi-family residential buildings. TOPSIS, a multi-criteria decision making technique was used to determine appropriate ventilation strategies in addition to occupant ventilation system operation preference.

A Study on the Development and Performance Evaluation of Permeable GFRP Strengthening Panel for RC Structure (투수성 GFRP 보강 복합체 개발 및 투수성에 대한 연구)

  • Jo, Byung Wan;Kang, Seok Won;Park, Cheol;Kim, Jang Wook
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.3
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    • pp.65-73
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    • 2013
  • Recently the exterior attaching reinforcement method is being often used by using FRP (Fiber Reinforced Polymer) as a method of strengthening concrete structure. this FRP exterior attaching reinforcement method has several advantages like high intensity, stiffness, good durability and easy installment comparing to its weight. but its structure is airtight covered by reinforcement material whose water permeability is low and water can't be discharged, thus it may provoke a damage to the structure after a long while. the main purposes of this study are to develop GFRP reinforcement material which can discharge the surface water properly and to measure its special functions. for this, we have changed the normal reinforcement material to water permeable structure and measured its water permeance modulus by an indoor test which shows the process of water permeance with the parameter of contained GFRP quantity. also tried to verify the measured value of the water permeance modulus in theory by analyzing the numbers on water permeance process. the test result showed that the biggest quantity of water, 0.5129 g/h $m^2$ was discharged when the fiber contained quantity reached at 75% and the tensile strength was also biggest by 476.6MPa at 75%, so it appeared that COSREM GP panel with 75% fiber contained quantity is the best in ventilation and structure.

A Study on the Thermal Stability of Long-Term Fuel Storage and Lifetime Estimation of Rubber O-ring in Contacted with Fuel (장기 저장연료의 열안정성 및 연료접촉 고무오링의 수명예측 연구)

  • Chung, K.W.;Hong, J.S.;Kim, Y.W.;Han, J.S.;Jeong, B.H.;Kwon, T.S.;Suh, D.O.;Sung, M.J.;Kwon, Y.I.
    • Tribology and Lubricants
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    • v.34 no.5
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    • pp.197-207
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    • 2018
  • Thermal deterioration of fuel due to long-term storage influences engine performance and causes malfunctions. Fuel stability is usually evaluated via heat resistance and thermal stability during a brief heat shock at high temperature; storage stability in this scenario means that there is very little change in the quality of the fuel during long-term storage. In addition, rubber-based products such as oil seals, O-rings, and rubber hoses can influence the quality of the fuel. When these rubber products are in contact with fuel, they can swell, mechanically weaken, and occasionally crack, thus leaking low molar weight rubber and additives including plasticizer and antioxidant into the fuel to degrade its properties and shorten its useful lifetime. This study determines the thermal stabilities of three kinds of synthetic fuels by evaluating their low temperature kinematic viscosities, chemical composition changes via GC analyses, gross heat of combustion, and color changes. We evaluate the compression set of O-rings by immersing one NBR and two FKM rubber O-rings in the three synthetic fuel samples in airtight containers at variable storage temperatures for six months; from this, we estimate the lifetimes of the O-rings using the Power law model. There were very little changes in the chemical compositions and gross heat of combustion after six months of the experiment. The lifetimes are thus dependent on the materials of the rubber products, and in particular, the FKM O-ring was calculated to have a theoretical lifetime of 200 to 5,700 years. These results indicate that the synthetic fuels maintain their physical properties even after long-term storage at high temperatures, and the FKM O-ring is suitable for long-term sealing of these fuels.

A Study on the Primary Energy Change Amount and Grade Correlation following Factor Changes such as Area, Point of the Compass, Standard Layer, Insulation, Airtight Joint and Others (지역, 방위, 기준층, 단열재, 기밀등 요소변화에 따른 1차에너지 변화량 과 연관성 연구)

  • Kim, Dae-Won;Chung, Kwang-Seop;Kim, Young-Il;Nam, Ariasae;Kim, Sung-Min;Cho, Young-Wook
    • Journal of Energy Engineering
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    • v.24 no.4
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    • pp.183-191
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    • 2015
  • Studies on the environment-friendly and permanent low energy saving measure are and will continue to be an eternal challenge. However, the demand is high for the technologies that can save energy significantly in everyday life that produce tangible benefits for the users by applying saving factors and that anyone can access easily when it comes the related procedure. Government policies related to the improvement of energy effect in the existing building structure are characterized by complex procedure. Moreover, cost required and reliability issue emerge when request is made to an expert. Accordingly, this study seeks to present energy improvement plan that can be utilized simply and conveniently at any place, any time by enabling customized design according to individual taste by enabling energy change amount and grade prediction when the users select only the part that they want to replace by using a simple program.

Volume of Water Storage and Evapotranspiration by Inserted Materials at a Reservoir of Porous Grass Block (저수형 잔디블록 저수조 내 충진재료에 따른 저수량 및 초종별 증발산량)

  • Han, Seung-Ho;Choi, Joon-Soo;Yang, Geun-Mo;Yang, Byoung-E;Kang, Jin-Hyoung;Kim, Won-Tae
    • Journal of the Korean Institute of Landscape Architecture
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    • v.34 no.5 s.118
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    • pp.76-83
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    • 2006
  • The purpose of this study was to investigate the performance of porous grass block. For the investigation, Festuca arundinacea and Zoysia japonica 'Zenith' were planted, and the volume of evapotranspiration and remains were examined based on different materials in the water tank in the experiment of Festuca arundinacea, the volume of water storage of treatment with perlite ($10.84{\iota}/m^2$) was higher than that with drainage ($7l/m^2$). The difference between the two was $3.84/m^2$. The drainage treatment without water storage capacity showed the higher degree of dryness in turf grass. The volume of evapo-transpiration of treatment with perlite was the highest (21.57mm/week). The volume of evapotranspiration of treatment with sand was 19.57mm/week, and with treatment with drainage was 18.24mm/week. Based on the measured volume of daily evapotranspiration of $2.60{\sim}3.08mm\;d^{-1}$, it was determined that the unit with water storage capacity would store water of one to two days usage compared to unite without such storage capacity. In the experiment of Zoysia japonica 'Zenith', the volume of water storage of treatment with perlite was $10.77l/m^2$ which was similar to the former experiment. The volume of evapotranspiration of treatment with perlite and sand were 21.64mm/week and 20.64mm/week, respectively. In case of airtight water tank, the volume was measured as 22.06mm/week. Each treatment has no notable difference in the volume of evapotranspiration. In conclusion, from the investigation in this study, porous grass block with water tank was found to be effective in plant growth under low irrigation. As the ecological area ratio and vegetated porous pavement have became more emphasized, additional study of rain infiltration and reservoir effect are needed in the future.

Evaluation of Food Safety Performance and Food Storage Condition in Restaurants against Climate Change (기후변화 대응 식품접객업소 식재료 안전관리 수행도 및 보관실태에 관한 연구)

  • Lee, Jung-Su;Bae, Young-Min;Yoon, Jae-Hyun;Kim, Bo-Ram;Yoo, Jin-Hee;Hyun, Jeong-Eun;Jung, Soon-Young;Cha, Myung-Hwa;Ryu, Kyung;Park, Ki-Hwan;Lee, Sun-Young
    • Journal of Food Hygiene and Safety
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    • v.29 no.3
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    • pp.195-201
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    • 2014
  • This study was conducted to investigate the current status of hygiene performance and food preparation/storage condition in restaurants during the summer season in order to evaluate the sanitary management systems in restaurants against climate change. Total 30 restaurants located in Gyeonggi participated in a survey in which they were asked current hygiene performance, food preparation/storage condition, and purchasing practices for 5 food ingredients. As results, regarding the performance degree of respondents on food hygiene management, the average scores of 9 questions were well over 4 points. However, only 6.83% of the respondents claimed that they use sanitizers (chlorine) to disinfect food ingredients. About food storage condition, a high proportion of respondents said that they store food materials in plastic bags or airtight containers following pretreatment and use refrigerator for the storage of pretreated food materials. However, 5.55% and 14.85% of respondents answered that they store pretreated food materials in the kitchen or inside of dining room, respectively. Respondents (21.50%) answered that they store pretreated food materials for more than 6 hours before cooking. Therefore, food materials need to be disinfected properly with sanitizer to remove microbial contamination and stored at refrigerator using closed bags or containers before cooking in order to prevent foodborne disease in restaurants especially during summer season.