• Transactions of the Korean Society of Mechanical Engineers
• /
• v.8 no.6
• /
• pp.544-552
• /
• 1984

A non-steady group combustion model of a spherical droplets cloud has been developed to access the non-steady effects of collective behavior of fuel droplets on combustion characteristics and cloud structure. A system of conservation equations of droplets cloud in axisymmetric spherical coordinate was solved by numerical methods for n-Butylbenzene(C$_{10}$ / $H_{14}$) It was found that the effect of initial droplet size on combustion characteristics is dominated compare with effects of cloud size and number density of droplets. For dense droplets cloud, external group combustion mode is established during main part of cloud life time, and internal and single droplet combustion modes are simultaneously established for the dilute droplets cloud. Radius of cloud and external envelope flame are slowly decreased during main part of cloud life time, and suddenly decreased at end of combustion period.d.

• Journal of Advanced Marine Engineering and Technology
• /
• v.16 no.1
• /
• pp.35-46
• /
• 1992

In this study, we calculated gas flow fields and distribution of fuel droplet and mass fraction using the CONCHAS-SPRAY code which modified to execute in IBM PC and changed three important factors, injection rate pattern (BASIC, I, II, III), different bowl shape and spray type. Especially vortices which be influenced by fuel-air mixing process, evaporation and flame propagation are generated more strongly in the bowl-piston type combustion chamber than in the flat-piston type. As the spray type changes, it is found that conical type produced large and strong vortices and fuel droplets are effictively diffused into the entire combustion chamber. As the injection rate pattern changes I, II, III based on BASIC type, we confirmed that End-of-Injection Effect strongly influence on droplets life time.

• Journal of the Korean Wood Science and Technology
• /
• v.11 no.3
• /
• pp.23-30
• /
• 1983

This experiment was carried out for diminishing the material loss and the damage of human life due to the fire disaster by treating plywood with fire retardant chemical solution. At this study, we observed and measured chemical retention, burning point, maximum flame length, flame exausted time, carbonized area, and weight loss of plywood treated by each solution of ammonium sulphate [$(NH_4)_2SO_4$] and monoammonium phosphate [$NH_4H_2PO_4$]. Obtained results at the study may be summarized as follows: 1. In case of monoammonium phosphate-treated plywood, every tested item of fire retardancy was shown more excellent at the 25% chemical concentration and shown also at 9 hours treatment except maximum flame length compared with ammonium sulphate-treated plywood. 2. However in case of ammonium sulphate-treated plywood, 6 hours treatment of fire retardancy was better than 9 hours treating time. 3. Monoammonium phosphate was generally better than ammonium sulphate in every tested item.

• Journal of Energy Engineering
• /
• v.16 no.3
• /
• pp.113-119
• /
• 2007

The auto-ignition characteristics and combustion behaviors of one-dimensional array of water-in-fuel droplets suspended in a high temperature chamber have been investigated experimentally with various droplet spacing and number of droplets. The fuels used were pure n-decane and emulsified n-decane with water contents varied from 10% to 30%. All experiments have been performed at 920 K under the atmospheric pressure. The number of droplets in an array were fixed as 3 or 5 and its spacing was varied from 3 mm to 7 mm by 1mm interval. The imaging technique with a high-speed camera has been adopted to measure the ignition delay and flame life time. The micro-explosion behaviors were also observed. As the droplet array sparing increased, the ignition delay also increased regardless of water contents. However, the life time of droplet array decreased as the droplet spacing increased. The full combustion time in array of 3 droplets was found to be longer than that for 5 droplets case due to the longer ignition delay.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.1
• /
• pp.1-8
• /
• 2013

The water-in-fuel droplets were applied to investigate the effect of mixing ratio between water and decane, ambient temperature, droplet size and spacing between droplets on ignition and micro-explosion in a heated chamber with high temperature. The ignition temperature of droplet was found lower as the droplet size was increased and the contents of water was decreased. The life time of droplet, however, decreases as the contents of water increases due to the micro-explosion. The occurrence of micro-explosion also increases as the size of droplets and the ambient temperature increase. The flame spread speed gets faster as the contents of water and the number of suspender decreases.

• Cross-Cultural Studies
• /
• v.42
• /
• pp.419-449
• /
• 2016

The Russian icon and Korean tangwha (幀畵, altar portrait of Buddha) are based on the similarity of the divine Being. Each has the characteristic index that forms an existential connection with the object and at the same time, implies the symbolic meaning of the scriptures and doctrines of the Russian Orthodox and Buddhists. Russian icon and Korean tangwha with these attributes have origins in the Byzantine, India and China. Unlike most religious art, Russian icon and Korean tangwha clearly reveal profane orientation and mystical elements. This artistic phenomenon has evolved from the mystical religious culture in Russia and tantric rituals of the early Joseon period. Iconostasis, created from historical figures of the Old Testament, Jesus, the New Testament represent the principles of the macrocosm. Each icon of iconostasis has integrity, while each floor has another narrative and a meta-discourse on the entire composition. Three-Platforms of amrtakundalin can also have a huge epic that is directed from the Low-Platform to the High-Platform for the purpose of salvation. While the narrative of iconostasis has a time structure, from the beginning of the universe up to date in chronological time, amrtakundalin have pictorial transitions of time and space that rises from this life to a heavenly world. Despite the different world views of the Russian Orthodox and Buddhists, iconographical format and symbolism of heaven and hell in the Iconostasis, Last Judgment and amrtakundalin are similar. There is a constant antagonism between heaven and hell, light and darkness, water and flame. Iconographical contents include the water of life and nectar, the book of life and 'eoppu', and the scales and mirror of Karma that discriminate between the good and evil before judgment. The dualistic coordinate concept such as light and darkness, life and death, or heaven and hell that appears in the narrative structure of iconostasis, the Last Judgment and amrtakundalin leads the people to spiritual awakening.

• Journal of the Society of Disaster Information
• /
• v.12 no.4
• /
• pp.381-388
• /
• 2016

In this study, we surveyed the supply and perception of Personal Protective Equipments for firefighters. As a result, most of the respondents answered that they were paid in accordance with the supply standard, but 12% of the respondents said that there were insufficient equipment. Also, satisfaction with the performance of the equipment is mostly satisfied, but the safety gloves are more than 50% dissatisfied. In summing up the results of the survey, it is urgently necessary to improve the current supply standard, which is determined by the life of PPE, to the replacement period according to the using time or frequency. Also, a new standard should be prepared through the follow - up study.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.4
• /
• pp.379-389
• /
• 2014

Fire detectors are designed to minimize loss of life from a fire alarm system as an alarm to help evacuate more quickly until the completion of the evacuation alarm should be continued. the purpose of such alarms in order to achieve the characteristic fire heat release rate reaches a certain level, or when a certain time has elapsed, when the heat detector is to be alarms to answer. Requires a quick response, it is desirable to install the sensor as much as possible, but taking into account the cost of installation problems by engineering approach to minimize the quantity and rapidity of detection capability should be increased. In order to increase the rapidity of fire detectors in a room according to the height of the sensing period is to be maintained the optimum distance of the fire detector detects characteristics should be considered. Differential spot-type heat detectors installed domestic basis, depending on the type of sensor that can detect one sensor area is limited and less than 4m ceiling height regulations and simply double the number in excess of 4m and intended to be installed.

• Journal of Energy Engineering
• /
• v.18 no.2
• /
• pp.101-107
• /
• 2009

The combustion characteristics of a single droplet of diesel and bio-diesel have been investigated experimentally with varying droplet size, ambient temperature and compound ratio in a high temperature chamber. The fuels used were diesel with bio-diesel contents varied from 0% to 100%. Each experiment has been performed from 970K to 1070K by 50K intervals. Imaging with a high-speed digital camera was adopted to measure the ignition delay and flame life-time, as well as to observe micro-explosion behavior. The increase of droplet size and decrease of furnace temperature cause an increase of the ignition delay time. As the bio-diesel content decreases, the ignition delay increases and the micro-explosion behavior is strengthened. It is also confirmed that the full combustion time decreases as the micro-explosion occurred.

• Archives of Plastic Surgery
• /
• v.36 no.5
• /
• pp.578-582
• /
• 2009

Purpose: In extensive deep burn of the lower limb, due to less amount of soft tissue, bone is easily exposed. When it happens, natural healing or reconstruction with skin graft only is not easy. Local flap is difficult to success, because adjacent skins are burnt or skin grafted tissues. Muscle flap or free flap are also limited and has high failure rate due to deep tissue damage. The authors acquired good outcome by performing one - stage operation on bone exposed soft tissue defect with AlloDerm$^{(R)}$(LifeCell, USA), an acellular dermal matrix producted from cadaveric skin. Methods: We studied 14 bone exposed soft tissue defect patients from March 2002 to March 2009. Average age, sex, cause of burn, location of wound, duration of admission period, and postoperative complications were studied. We removed bony cortex with burring, until conforming pinpoint bone bleeding. Then rehydrated AlloDerm$^{(R)}$(25 / 1000 inches, meshed type) was applicated on wound, and thin split thickness(6 ~ 8 / 1000 inches) skin graft was done at the immediately same operative time. Results: Average age of patients was 53.6 years(25 years ~ 80 years, SD = 16.8), and 13 patients were male(male : female = 13 : 1). Flame burn was the largest number. (Flame burn 6, electric burn 3, contact burn 4, and scalding burn 1). Tibia(8) was the most affected site. (tibia 8, toe 4, malleolus 1, and metatarsal bone 1). Thin STSC with AlloDerm$^{(R)}$ took without additional surgery in 12 of 14 patients. Partial graft loss was shown on four cases. Two cases were small in size under $1{\times}1cm$, easily healed with simple dressing, and other two cases needed additional surgery. But in case of additional surgery, granulation tissue has easily formed, and simple patch graft on AlloDerm$^{(R)}$ was enough. Average duration of admission period of patients without additional surgery was 15 days(13 ~ 19 days). Conclusion: AlloDerm$^{(R)}$ and thin split thickness skin graft give us an advantage in short surgery time and less limitations in donor site than flap surgery. Postoperative scar is less than in conventional skin graft because of more firm restoration of dermal structure with AlloDerm$^{(R)}$. We propose that AlloDerm$^{(R)}$ and thin split thickness skin graft could be a solution to bone exposured soft tissue defects in extensive deep burned patients on lower extremities, especially when adjacent tissue cannot be used for flap due to extensive burn.