• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.1-8
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• 2003

The heat transfer and flow measurements on a cylindrical pedestal mounted on a flat surface with a turbulent impinging jet were made. The experiments were made for the jet Reynolds number of Re = 23,000, the dimensionless nozzle-to-surface distance of L/d = 2~10, the dimensionless pedestal height of H/D = 0~1.5. Measurements of the surface temperature and the Nusselt number distributions on the plate surface were made using liquid crystal and shroud-transient technique. Flow measurements involve smoke flow visualization and the wall pressure coefficient. The results show that the wall pressure coefficient sharply decreases along the upper surface of the pedestal. However, the pressure increases when the fluid escapes from the pedestal and then collides on the plate surface. The secondary maxima in the Nusselt numbers occur in the region of 1.0 $\leq$ r/d $\leq$ 1.9. Their values for the case of H/D = 0.5 are maximum 80% higher than those for other cases. The formation of the secondary maxima may be attributed to the reattachment of flow on the plate surface which was separated at the edge of the pedestal.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.1-8
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• 2001

All objects emit thermal radiation and this radiation is the basis of the techniques used to detect flames. The usual phenomena occurring in the initial stage of the fire are generally invisible products of a combustion and visible smoke. Liquid or gaseous materials do not undergo a smoldering stage so that fires develop very rapidly. Also, the heat generated by the initial flames is usually not sufficient to activate a heat detector. In this case the most effective criterion for automatic fire detection is the flame. According to the fire regulation of korea, the compulsory standard provided that a flame detector shall be installed in a place that the attachment height of detector is higher than 20 m, chemical plants, hangar, refinery, etc.. The results of the research and development are discriminated between a flame and other radiant emitters, developed a UV detector tube contains an inert gas which absorbs UV radiation, developed PZT pyroelectric element is based on the use of photovoltanic cell, developed IR band-pass filter that only allow a 4.3 $\mu\textrm{m}$ radiation wavelength to reach the sensors and developed UV-IR combination flame detector combined into a single detection device.

• Journal of Nutrition and Health
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• v.32 no.7
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• pp.812-820
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• 1999

The aim of this investigation was to assess the difference of health behaviors, dietary patterns and nutrient intakes between smokers and nonsmoker from 435 free living elderly in Kyunggi province. The study subjects were interviewed to collect general characteristics and health behaviors such as smoking, exercise, alcohol consumption, and food habits by questionnaires and nutrient intakes by a 24-hour recall, and weight, height, waist, hip, and blood pressure were measured. The percentages of smoker were 52.3% in males and 12.1% in females. Current smokers were fond of alcohol, salty or hot food, tended to have meals irregularly and insufficient sleep, and were inactive lifestyle compared to nonsmokers. Smokers consumed fewer servings of vegetables, fruits, and beans and their products. Women who smoked consumed less energy, carbohydrates, and vitamin E than nonsmokers, and their nutrient adequacy ratio of protein, iron, phosphate, niacin, vitamin B1, and vitamin C were significantly lower than nonsmokers. There were no differences of nutrient intakes and nutrient adequacy ratio between smokers and nonsmokers in male subjects. In conclusion, elderly smokers tended to have less healthy life style, food habit, and dietary nutrient intakes which may influence the deleterious effects of smoke components on cancer and coronary heart disease risk, thus health education program should include nutrition education as well as smoking cessation.

• Tunnel and Underground Space
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• v.14 no.4
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• pp.269-274
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• 2004

In this study reduced-scale experiments were conducted to determine the backlayering distance in tunnel fires. The 1/20 scale experiments were carried out under the Froude scaling using ethanol square pool fire ranging from 8 to 1km in each side with total heat release rate from 2.47 to 12.30 ㎾. It has been found that ventilation velocity increases with aspect ratio(tunnel height/tunnel width). At L$\_$B/$\^$*/ ＜5 the ventilation velocity increases proportional to the backlayering distance from 0.25 power of the heat release rate. However at L$\_$B/$\^$*/ $\geq$5 the ventilation velocity varies as the 0.3 power of the heat release rate.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.35-42
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• 2003

Nitric Oxide(NO) is produced in many organs of the body, including the lung and airways, and it is detectable in the exhaled air. The measurement of exhaled NO(eNO) provides a simple non-invasive means for measuring airway inflammation, such as asthma. We measured eNO among adult male workers to examine the distribution of eNO in healthy people and to find factors affecting eNO. We measured eNO in a sample of 921 adult workers who also performed lung function test and skin prick test. Exhaled NO was measured in a sitting posture without using a nose clip and NO free gas. NO was measured at three expiratory rates(l8; 42; 71 $m\ell$/sec) and the flow rate of 71 $m\ell$/sec was used in analysis. The average eNO concentration was 5.29 $\pm$ 2.98 ppb. The level increased with age but not significantly(P=0.0529). Exhaled NO showed positive relations to the height(P=0.0001), pollen 1 (P=0.0124), asthma history(P=0.0212), allergic rhinitis symptom(P=0.0302). Exhaled NO Concentration of smokers( 4.62 ppb) was significantly lower than that of nonsmokers(5.99 ppb; P<0.0001).

• Fire Science and Engineering
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• v.25 no.5
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• pp.14-20
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• 2011

As the height of the building increases, the stack effect in stairwell that is main facilities for evacuation becomes stronger. While the pressure rise in stairwell causes difficulties on opening the door for evacuation and has effect on smoke control system, reduction of stack effect will be necessary for providing more safe evacuation environment. The field experiments on pressure field in high-rise building are carried out to present reduction method of stack effect and the numerical analyses using network model are proceeded to design quantitatively the reduction method. As the air flow supplied from outside in lower stair and exhausted to outside in upper stair is formed in stairwell, the stack effect in stairwell is expected to be decreased.

• Fire Science and Engineering
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• v.28 no.6
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• pp.58-61
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• 2014

Flame detectors has been used more than heat & smoke detector, because this is more effective to catch fire and ceiling height in spite of high price. For upgrade to flame detector, Compare to national or abroad standard about performance test, sensitivity test, sectioning indoor or outdoor, after service and management. As a result, Europe and America have only sensitivity test, no have not operation test and sectioning indoor & outdoor. In performance test, action is put to focus to credit and durability, Not operation test is to be able to tune the sensitivity to match the environment of the site. Also, we need code about aftercare, quality assurance responsibility and implement special detector institution by Certificate Authority implement.

• Fire Science and Engineering
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• v.24 no.3
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• pp.99-105
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• 2010

Ventilation fans utilized correctly can increase the effectiveness of fire fighters and survivability of occupants. It is possible to increase the pressure of a corridor to prevent the infiltration of smoke. In this study, experiments were carried out to evaluate ventilation effectiveness in corridor fires. Corridor used in the experiment was 20 m long. Heptane was used as a fuel. Temperature and visibility were measured in order to evaluate ventilation effectiveness according to the position of a vent. Vent distance ranged from 0 m to 4 m and height varied from 0 m to 1.5 m. When the vent was positioned 2 m long and 0.75 m high the result was most effective.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.3
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• pp.177-186
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• 2003

In the present study, the flow characteristics of developing turbulent flows are investigated at the exit region of a square cross-sectional 180" curved duct with dimensions of 40mm$\times$40mm$\times$4000mm (height $\times$ width $\times$length). Smoke particles produced from mosquito coils were used as seed particles for the LDV measurement. Experiments were carried out to measure axial velocity profiles, shear stress distributions and entrance lengths by using an LDV system and Rotating Machinery Resolver RMR with PHASE software. Experimental results clearly show that the time-averaged Reynolds number does not affect oscillatory flow characteristics because the turbulent components tend to balance the oscillatory components in the fully developed flow region. Also, the velocity profiles are in good agreement with 1/7power law such as the results of steady turbulent flows. The turbulent intensity linearly increases along the walls and is slightly higher, especially in the period of deceleration. On the other hand, the LDV measurements show that shear stress values in slightly higher in the period of deceleration due to the flow characteristics in the exit region. The entrance length where flows become stable appears at the point that is 40 times the length of hydraulic diameter.eter.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.4
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• pp.225-234
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• 2022

The flow field measurement above whole area of the flight deck on 'Landing Platform Helicopter (LPH)' was performed by using PIV system in wind tunnel. In various heading angle conditions (0deg, -30deg, -45deg, -60deg, -75deg and ±90deg), the velocity fields such as U velocity & V velocity were measured at three different height above flight deck. Due to the geometrical characteristics of several bodies like deck, crane and super-structure, various vortex were generated. When the heading angle is 0deg, the deck edge vortex by flight deck and massive separation by super-structure were clearly observed by visualization with smoke and PIV, respectively. In other heading angles, the acceleration of flow in space between crane and super-structure were detected. And area with flow separation by super-structure is directly related to the heading angle of vessel.