• Journal of Hydrogen and New Energy
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• v.18 no.4
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• pp.374-381
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• 2007

In order to verify the feasibility of expansion of back-fire limit equivalence ratio in the hydrogen-fueled engine with external mixture, the characteristics of performance and combustion are experimentally analyzed with change of intake/exhaust valve timings under the fixed valve overlap period of $0^{\circ}$ CA(non-valve overlap period). These characteristics are also tested for the change of exhaust valve closing timing while intake valve opening timing is fixed to clear the main cause of back-fire occurrence. As the results, the less valve overlap period center is retarded, the more back-fire limit equivalence ratio increases and back-fire does not occurred after TDC. In addition, it was shown that the control of back-fire is dependent on intake valve opening timing than valve overlap period.

• Journal of Hydrogen and New Energy
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• v.18 no.3
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• pp.348-355
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• 2007

To grasp a feasibility of back fire control by valve overlap period, back fire limit equivalence ratio was estimated with valve overlap period which has the same supply energy and positive intake pressure as valve overlap period $300^{\circ}\;CA$. As the result, it was shown that the smaller valve overlap period has the higher back fire limit equivalence ratio under valve overlap period $300^{\circ}\;CA$ as well as VOP $0^{\circ}\;CA$. This result means that expansion of back fire equivalence ratio by decreasing valve overlap period was caused by decrease of back flow duration of flame from in-cylinder to intake port than decrease of lower supply energy.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.32-37
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• 2010

When back-out & firing Process applies heat, hume is piled up in exhaust duct by organic compound and it have high dangerousness. There by, the process is happening a lot of damage that is exhaust duct fire. However we do not have certain fire dangerousness estimation and digestion countermeasure. So we need preventive measure. Back-out & firing is a process which has fine structure, electrical and mechanical characteristics, such as firing kiln and back-out kiln which has pipe line and box type. The box oven is made of heating coil, fan motor and control panel. Back-out & firing process has air circulation institution of quick ventilation type. When we operate this process for long time, fire can break out easily. Duct is made by zinc shredder. If fire breaks out in duct inside, fire by deposit fume can be dispersed easily. Accordinglym, This project estimate danger for back-out & firing process exhaust duct through real fire test. And there is purpose of study to establish preventive measure.

• Fire Science and Engineering
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• v.27 no.1
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• pp.31-38
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• 2013

The pressurized smoke control system is important for fire safety in building because it is directly concerned with egress time of people. Even though the damper plays an essential role in the pressurized smoke control system, the phenomena of backflow smoke occurs for a certain the damper position. The research for a position of damper effects on distribution of air flow at the fire door is not performed. In this study, numerical simulation using FDS 5.5 was carried out to analyze the effect of the position of damper on flow distribution at the fire door. To simulate real situation, effects of opening and closing of fire door was considered. As a result, when HRR was between 200 kW and 400 kW, in the case which the damper was on the opposite wall of the fire door, the back flow to the vestibules was large compared to the two other cases of damper position. But when HRR was above 400 kW, Effect on damper position was not occurred.

• Fire Science and Engineering
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• v.22 no.1
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• pp.16-23
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• 2008

In this research, the visualization experiment for a scaling tunnel was conducted to establish the optimum fire protection system in tunnel fires. In order to find the optimal operating condition of jet fan with the fire, the characteristics of smoke propagation was considered to find the optimal operating condition of jet fan at the time of tunnel fire, the concentration of smoke was measured experimentally for various jet fan position and it's operating condition. As a result, when jet fan in the vicinity of fire operates at the upstream, the back-layering of the smoke should be considered with separation distance from the fire source. The distance between the jet fan and the fire should be longer than 50 m. On the other hand, when the vicinity jet fan operates at the downstream, the back-layering of smoke does not occur, but stratification is not maintained because the smoke dispersion occurs at the downstream due to the operation of the jet fan.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2142-2143
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• 2011

Amphibious possible, and good fuel economy, so as leisure and transport has increased the use of hovercraft. Fire started in Korea, the prevalence is increasing in demand as the trend has been increasing steadily. In this paper, the hovercraft's forward and backward direction can be controlled in order to free the reverse bucket control system was developed. Control due to development by promoting the flow of air and turn right, turn left and easy to reverse the life-saving and stable at high speed, etc. has made possible the operation of hovercraft. To prove the validity of the proposed controller in Matlab simulation and the actual delivery at the firehouse, built into a model for the demonstration test was performed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.9
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• pp.662-668
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• 2007

In this study, jet fans are installed with 4 cases in the straight long tunnel; inlet-side setup, middle-side setup, outlet-side setup, and dispersion setup. A bus is selected as fired car, of which fire size is 20MW. And fired car locates at 100m, 700m, 1500m position from tunnel inlet, respectively. FLUENT, commercial finite-volume code, is used to analyze the performance. The velocity profile, $CO_2$ concentration, temperature distribution are examined for analysis. Performance of smoke control is compared by the backlayering length. Consequently, inlet-side setup of jet fans is a little more efficient than other cases considering the fire occurrence frequency in tunnel.

• Korean Journal of Acupuncture
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• v.21 no.3
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• pp.147-158
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• 2004

Objectives : This study was aimed to investigate the methods for acupuncture and moxibustional treatment to insomnia Methods : The insomnia is classified by seven cause at main subject. According to this, arrange the acupuncture and moxibustional treatment for classical books, and explain eight meridian related to insomnia. Results : 1. Insomnia means deficiency of sleeping and it is the word generally used when a short period of sleeping, difficulty for deep sleeping and difficulty for recovery of original vital energy comes out. In oriental medicine, they understand that uneasiness condition occurred by abnormal operation of the internal organs as heart, liver, gallbladder, spleen, stomach, kidney, etc. caused by external affection or internal injury becomes Insomnia. 2. Cause of insomnia can be classified majorly as fire-transformation of liver and gallbladder , inner shaking of phlegm-heat , insufficiency of both the heart and the spleen, disharmony between heat and kidney, the dysfunction of the stomach, timidity of heart and gallbladder, the deficiency of Qi of the lung. They make insomnia with bad influence upon body and spirit. 3. The meridian system such as Heart Meridian of Hand Soeum, Pericardium Meridian of Hand Gworeum, Stomach Meridian of Foot Yangmyeong, Spleen Meridian of Foot Taeeum, Bladder Meridian of Foot Taeyang, Kidney Meridian of Foot Soeum, Gallbladder Meridian of Foot Soyang, Liver Meridian of Foot Gworeum and Lung Meridian of Hand Taeeum are used to treat insomnia. Sinmun acupoint and Naegwan acupoint are often used in particular because the they are good for calmming the spirit, the heart and purging the heart of (pathogenic) fire. 4. Especialy, Back-Su points of Bladder Meridian of Foot Taeyang was used by each causes. The Back-su Points was mainly used for heal the insomnia because the Back-Su points has good competent to control the ability of internal organs by direct effect to it. It is because the vitality flows through around back-Su. Conclusions : It comes to a conclusion as follows with research for relevancy of the main cause of insomnia and meridian system includes meridian point.

• The Korean Journal of Emergency Medical Services
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• v.19 no.3
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• pp.69-85
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• 2015

Purpose: This study aimed to investigate the prevalence of musculoskeletal symptoms (MSSs) and their correlation with subjective health condition (SHC) among emergency medical technicians (EMTs). Methods: A self-reported questionnaire was disseminated to EMTs (N=257) at emergency medical institutions and fire stations. Results: The prevalence of MSSs was very high in the studied EMTs: 88.3% reported having MSSs. The most commonly affected site was the lower back (73.9%) followed by the neck (56.8%) and the shoulder (55.6%). MSSs were more common in women than in men, and its frequency increased with age. MSSs in the neck and shoulder were more increased in EMTs with < 1 year of service. MSSs in the hand / wrist / finger or leg / foot were significantly increased in EMTs of emergency medical institutions than those of fire stations. Job satisfaction was significantly lower in those with MSSs of the lower back. The subjective heath condition was decreased with age, marriage, or smoking. There was significant corelation between MSSs and SHC. Conclusion: This study suggests that MSSs are a reasonably common problem for EMTs, and that solutions need to be imposed such as some actual tasks or items related to work postures, work control, and work organization.

• Fire Science and Engineering
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• v.25 no.4
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• pp.89-93
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• 2011

It is not recommended that elevator use for egress at (super) high rise buildings because elevator shaft main roles to spread of fire smoke. But in North America used to protect this area by elevator shaft pressurization. These tests are performed at high rise apartment to verify that elevator shaft pressurization can protect to spread of fire smoke or not. and verify to used for egress at fire. Pressurization at elevator shaft make pressure difference of 50 Pa all floor at 150 CMM because this method have low friction loss from air flow. Also when dwelling door and elevator door are opened that critical velocity is performed to protect of back-layering from fire room for escape routs by 180 CMM. Therefore through out these pressurization tests by elevator shaft are estimated to have less overpressure because supply air difference are low between to satisfy critical velocity at one door opened and maintain to pressure difference all doors closed. Finally we verified that disable or residual people can use elevator for egress at fire by elevator shaft pressurization.