• Title/Summary/Keyword: Emergency Load

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Seismic Performance Evaluation of the Li-Polymer Battery Rack System for Nuclear Power Plant (원자력발전소용 리튬폴리머 배터리 랙 시스템의 내진성능평가)

  • Kim, Si-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.13-19
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    • 2019
  • After the Fukushima nuclear accident, a new power supply using a lithium polymer battery has been proposed the first time in the world as the safety of the emergency battery facility has been required. It is required to have the safety of the rack system in which the battery device is installed in order to apply the proposed technology to the field. Therefore, the purpose of this study is to evaluate the seismic performance of string and rack frame for lithium-polymer battery devices developed for the first time in the world to satisfy 72 hours capacity. (1) The natural frequency of the unit rack system was 9 Hz, and the natural frequency before and after the earthquake load did not change. This means that the connection between members is secured against the design earthquake load. (2) he vibration reduction effect by string design was about 20%. (3) As a result of the seismic performance test under OBE and SSE conditions, the rack frame system was confirmed to be safe. Therefore, the proposed rack system can be applied to the nuclear power plant because the rack system has been verified structural safety to the required seismic forces.

An Ergonomic Analysis for Heavy Manual Material Handling Jobs by Fire Fighters (소방대원의 중량물작업에 대한 인간공학적 분석)

  • Im, Su-Jung;Park, Jong-Tae;Choi, Seo-Yeon;Park, Dong-Hyun
    • Fire Science and Engineering
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    • v.27 no.3
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    • pp.85-93
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    • 2013
  • Modern fire fighting jobs have been expanded to include areas of rescue, emergency medical service as well as conventional fire suppression, so that load for fire fighting jobs has been increased. Specifically, musculoskeletal disorders (MSDs) such as low back injury have been considered as one of major industrial hazards in heavy manual material handling during fire fighting jobs. This study tried to evaluate risk levels and to prepare background for reducing risk levels associated with heavy manual material handling during fire fighting jobs. This study applied two major tools in evaluating heavy manual material handling jobs which were NLE (NIOSH Lifting Equation) and 3DSSPP (3D Static Strength Prediction Program). A risk index in terms of heavy manual material handling during fire fighting jobs was identified. This index consisted of seven risk levels ranged from nine points (the first level) to three points (the seventh level). There was no job associated with the first level (the highest risk level) of index. There was only one job (life saving job) belonging to the second level (the second highest risk level) of index. The third level had jobs such as usage of destruction equipment and lifting patient. A total of basic eighteen jobs was categorized into six different levels (2nd-7th levels) of index. The outcome of the study could provide a good basis for conducting job intervention, preparing good equipment and developing good education program in order to prevent and reduce MSDs including low back injury of fire fighting jobs.

Study on Development of Automated System for Hazard Screening at Analysis (위험 선별 및 분석 통합 자동화 시스템 개발에 대한 연구)

  • 한의진;김용하;최승준;김구회;윤인섭
    • Fire Science and Engineering
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    • v.17 no.4
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    • pp.20-27
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    • 2003
  • Hazard Analysis is one of the basic tasks to ensure the safety of chemical plants. However, it is an arduous, tedious, time-consuming work and requires multidisciplinary knowledge and demands considerable cognitive load from the analysts. To overcome these problems, there have been attempts to automate this work by utilizing computer technology, particularly in the area of knowledge-based technique. There is two methods in the risk assessment of Chemical plant; quantitative and qualitative risk assessment. Both of them have been applied respectively, but if the integrated method of quantitative and qualitative risk assessments is used, all of the advantage of two methods can be applied. It is difficult to carry out integrated risk management of chemical plant. Therefore, automated integration system of risk management is necessary. We developed S/W Automated System for Hazard Screening & Analysis(ASCA) and applied to practical plant. By applying ASCA to case study, we can get the information about relative ranks of equipments, variable deviation, and consequence of potential accident. In this study, we applied ASCA to the H.T.U(Hydrotreating Unit) of the process to produce aromatic material. We could know relative ranks of equipments, variable deviation of malfunction in storage tank, D-101, and consequence of potential accident using ASCA. If integrated risk management in the chemical plant is applied, we can develop the emergency plan and prevent the accident.

Development and Evaluation of Rollator for Elderly Farmers

  • Lee, Kyung Suk;Kim, Kyung Ran;Kim, Hyo Cher;Chae, Hye Seon;Kim, Sung Woo;Seo, Min Tae
    • Journal of the Ergonomics Society of Korea
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    • v.33 no.6
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    • pp.487-497
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    • 2014
  • Objective: This study aims to develop and evaluate a multi-purpose rollator, which may be used as a seat, as a traditional walker, or as a storage basket for elderly farmers. Background: The rollators on the market are not user-friendly designed and seen inconvenient for elderly farmers to use, although they are sold at considerably high price. Since they lack enough space to load stuffs and are not durable or stable enough, they do not seem to be suitable for elderly farmers to use in rural areas. Method: Two types of methods were used in this study. First, the survey consisted of 19 questions was conducted among elderly farmers in rural areas, after using the developed rollator, to evaluate the usability of the rollator developed in this study. Second, EMG experiment was conducted to compare the existing rollator and developed rollator quantitatively. Through this experiment, we tried to verify the differences of muscle responses, when using the traditional and the developed ones, which have their own brake system, in the ramp. Results: The developed rollator was highly evaluated in most of the questions in the usability survey, except for the 'Weight' category in which the opinions were divided into three different types (Worse: 31%, Similar: 30%, Better: 36%). The result of EMG experiment showed that the existing rollator (7.4%MVC) demands more muscle strength than the developed rollator (5.5%MVC) does. By statistically analyzing the results of upper limb and lower limb respectively, we found out that all the muscles except deltoid in upper limb showed statistically significant differences in muscle activity when using the existing and the developed rollator. However, there was no statistical difference in lower limb muscles. Conclusion: The developed rollator in this study has maximized the functionality of the brake system, the storage and the chair, which were pointed out as the weaknesses of existing rollators. Furthermore, the developed rollator is designed to be more user-friendly, safe, durable, and effective for elderly farmers to use in rural areas, where roads are rough and bumpy. Application: We expect that the emergency brake system developed in this study would be utilized for other convenience equipment, such as strollers and carts, and that it would be able to develop and produce more secure and reliable equipment in the future.

Study of the method of production of excavated arrow bundle and its conservation treatment (발굴 출토 화살다발 제작기법 연구 및 보존처리)

  • Lee, Byeonghoon;Choi, Bobae;Huh, Ilgwon
    • Conservation Science in Museum
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    • v.25
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    • pp.9-26
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    • 2021
  • This paper describes the production methods that were originally used for an arrow bundle excavated from a Bronze Age residential area in Auraji in Jeongseon, Gangwon-do Province and the conservation treatment process that it subsequently underwent. An arrow conventionally consists of an arrowhead and a shaft. It is rare to excavate a shaft along with an arrowhead in a complete form since the shaft is made of organic materials. Notably, the arrow bundle from the Auraji site is of great significance as it shows traces of tangless stone arrowheads attached to charred shafts and offers an important case of the split end of a piece of a tree being inserted into an arrowhead. For a further examination of the characteristics of the arrows from Auraji, microscopic investigation was conducted and the type of wood used for the arrow shafts was examined. The sequence and direction of processing and the particle sizes of the grinding tools were revealed through the analysis of traces of grinding on the stone arrowheads. The shaft is presumed to have been made from a green length of three-year-old willow (Salix spp.). A curing agent with a high degree of waterproofing and reversibility was used during the on-site curing process according to demands of the surrounding environment, and a technique that the authors call the "Bridge" method was used for emergency collection of the relics. Once the bundle was transferred to the conservation treatment lab, reinforcing materials were carefully chosen as it was important not to damage the relics during the process of turning them for the repair of their reverse sides. For this purpose, artificial clay was selected since it can safely bear a load and has excellent physical properties. Finally, detached parts were rejoined, the relics and their surrounding materials were cleaned, and the bottom sides were finished with epoxy resin prior to the display of the relics at the museum.

Ground Separation Test to Verify Separation Stability of External Fuel Tank (외부연료탱크의 분리 안정성 검증을 위한 지상 분리시험)

  • Kim, Hyun-gi;Hong, Seung-ho;Ha, Byung-geun;Kim, Sung-chan;Lee, Jun-won
    • Journal of Aerospace System Engineering
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    • v.16 no.3
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    • pp.99-104
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    • 2022
  • Aircraft pylon connects the engine or external stores to the main wing, and transfers the load acting on the pylon to the main structure of the aircraft. In particular, it should perform the function of separating the external store mounted on the pylon in case of emergency or mission performance. At this time, if the separation of the external store is not performed properly due to peripheral air flow or functional problems during the separation process of the external store, it may seriously impact the survivability of the aircraft. For this reason, to apply an external attachment to an aircraft, it is necessary to prove the stability of the external attachment in the separation situation in advance. In this paper, we present the result of the ground separation test performed to confirm that the external fuel tank, which is an external attachment, can be safely separated from the pylon. As a result of the test, the separation movement of the external fuel tank was measured with a high-speed camera, and the stability of the separation of the external fuel tank from the pylon were confirmed through the ground separation test. Additionally, the test result provides basic data for the stability evaluation of the separation of external attachments in actual aircraft.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

The Construction Direction of the ROK NAVY for the Protection of Marine Sovereignty (국가의 해양주권 수호를 위한 한국해군의 전력건설 방향)

  • Shin, In-Kyun
    • Strategy21
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    • s.30
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    • pp.99-142
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    • 2012
  • Withe increased North Korea's security threats, the South Korean navy has been faced with deteriorating security environment. While North Korea has increased asymmetric forces in the maritime and underwater with the development of nuclear weapons, and China and Japan have made a large investment in the buildup of naval forces, the power of the Pacific fleet of the US, a key ally is expected to be weakened. The biggest threat comes from China's intervention in case of full-scale war with North Korea, but low-density conflict issues are also serious problems. North Korea has violated the Armistice Agreement 2,660 times since the end of Korean War, among which the number of marine provocations reaches 1,430 times, and the tension over the NLL issue has been intensifying. With tension mounting between Korea and Japan over the Dokdo issue and conflict escalating with China over Ieo do Islet, the US Navy has confronted situation where it cannot fully concentrate on the security of the Korean peninsula, which leads to need for strengthening of South Korea's naval forces. Let's look at naval forces of neighboring countries. North Korea is threatening South Korean navy with its increased asymmetric forces, including submarines. China has achieved the remarkable development of naval forces since the promotion of 3-step plan to strengthen naval power from 1989, and it now retains highly modernized naval forces. Japan makes an investment in the construction of stat of the art warship every year. Since Japan's warship boasts of its advanced performance, Japan's Maritime Self Defense Force is evaluated the second most powerful behind the US Navy on the assumption that submarine power is not included in the naval forces. In this situation, naval power construction of South Korean navy should be done in phases, focusing on the followings; First, military strength to repel the energy warship quickly without any damage in case of battle with North Korea needs to be secured. Second, it is necessary to develop abilities to discourage the use of nuclear weapons of North Korea and attack its nuclear facilities in case of emergency. Third, construction of military power to suppress armed provocations from China and Japan is required. Based on the above naval power construction methods, the direction of power construction is suggested as follows. The sea fleet needs to build up its war potential to defeat the naval forces of North Korea quickly and participate in anti-submarine operations in response to North Korea's provocations. The task fleet should be composed of 3 task flotilla and retain the power to support the sea fleet and suppress the occurrence of maritime disputes with neighboring countries. In addition, it is necessary to expand submarine power, a high value power asset in preparation for establishment of submarine headquarters in 2015, develop anti-submarine helicopter and load SLAM-ER missile onto P-3C patrol aircraft. In case of maine corps, division class military force should be able to conduct landing operations. It takes more than 10 years to construct a new warship. Accordingly, it is necessary to establish plans for naval power construction carefully in consideration of reality and future. For the naval forces to safeguard maritime sovereignty and contribute to national security, the acquisition of a huge budget and buildup of military power is required. In this regard, enhancement of naval power can be achieved only through national, political and military understanding and agreement. It is necessary to let the nation know that modern naval forces with improved weapon system can serve as comprehensive armed forces to secure the command of the sea, perform defense of territory and territorial sky and attack the enemy's strategic facilities and budget inputted in the naval forces is the essential source for early end of the war and minimization of damage to the people. If the naval power construction is not realized, we can be faced with a national disgrace of usurpation of national sovereignty of 100 years ago. Accordingly, the strengthening of naval forces must be realized.

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Assessment of Refuge Safety in Accomodations According to Awareness and Usability of Descending Life Lines and Simple Descending Life Lines (완강기 및 간이완강기의 인지·사용능력에 따른 숙박시설의 피난안전성 평가)

  • Han, Dong-Gew;Kong, Ha-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.11-21
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    • 2019
  • The purpose of this study is to evaluate the awareness and usability of descending life lines and simple descending life lines for fire situations in the accommodation of the public officials who are responsible for supervising the installation and maintenance of descending life lines and simple descending life lines. The main results of the study are summarized as follows. First, in comparison of the ability to distinguish between descending life lines and simple descending life lines, the majority of female public officers in general administrative services do not have the ability to distinguish between descending lifelines and simple descending life lines, so they should be able to improve their ability to distinguish descending life lines. Also, institutional strategies are needed to regularly receive education through the Safety Experience Center in order to prevent safety accidents such as falling in emergency situations. Second, as a result of verifying reusability of simple descending life lines by gender and occupation, most public officers with the exception of half of the firefighting officers were analyzed as having no ability to reuse the simple descending life lines. Therefore, it is necessary to change the relevant laws so that only the installation of descending life lines which can be used continuously is permitted, except for the simple descending life lines among the evacuation instruments to be additionally installed in each room of the accommodation. Third, in terms of the ability to perceive the maximum load of the descending life lines according to occupation, the perception ability of the rescuers was the highest and the perception ability of the fire service personnel was the lowest. In order to improve the perception abilities of the fire service personnel, it is necessary to strengthen the theoretical and practical education of descending life lines in collective education such as the command-enhancing training which is regularly carried out in fire service academy. Lastly, it is believed that it is more effective to conduct the experience training of the descending life lines by imagining the fire in accomodations rather than other facilities, because it is the location where fires are actually seen the most.