• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.327-334
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• 1995

In order to observe the influence of pulsed Nd:YAG laser at its out-of-contact with dentin on tooth temperature, we have applied pulsed Nd:YAG laser to 2mm thick dentin sample at a point of contact and from a distance of 1mm, 2mm, 3mm and 4mm with an energy of 0.3W, 0.5W, 0.8W, 1.5W and 2.0W. They were exposed to periods of 3 seconds, 6 seconds, 9 seconds and 15 seconds respectively and measured temperature changes. The results as follows : 1. When the time ad intensity of power were constant, the temperature changes on dentin of tooth depended on the distance. The temperature increased when the laser intensity increased bu two other conditions were contact. 2. At the point of contact, the temperature has risen over $5^{\circ}C$ regrdless of intensity of the power or the time. However, there was $5^{\circ}C$ fluctuation with 0.3 W for 3 seconds treatment. 3. The temperature change was less than $5^{\circ}C$ thermal change at the distance of 1mm and 2mm respectively when lased for 3 seconds, 6 seconds, 12 seconds and 15 seconds with 0.3 W. Similar results were observed at 3 and 6 seconds treatment with 0.5 W and at 3 seconds treatment with 0.8 and 1.0W respectively. 4. It showed less than 5(C thermal change when lased for 3 seconds, 6 seconds, 9 seconds, 12 seconds and 15 seconds with 0.3W at the distance of 3mm and 4mm. The same results were seen in 3 seconds, 6 seconds and 9 seconds treatment with 0.5W and in 3 seconds with 0.8W and 1.0W respectively. As we have seen the above, the results has indicated that pulsed Nd:YAG lasing at its off contact on dentin of 2mm thickness will not cause irreversible changes if lasing intensity, lasing distance and lasing time are appropriate.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1324-1333
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• 2010

This paper is used in a recent civil engineering field in three-dimensional laser-meter tiles using thermal imaging cameras for the weathered rock slopes precisely measured indirectly, to the degree that began in the will. In the field is difficult to access the degree of weathering of the rock slope to the existing direct way to compensate for the shortcomings of 3D Terrestrial Laser Scanner and weathering characteristics of rocks using thermal imaging cameras to get the information to analyze the degree of rock weathering is. Intensity of 3D TLS and the thermal camera with image analysis to analyze the degree of weathering of bedrock in the field of core drilling targeting indoor laboratory tests were analyzed through the study. Granite, gneiss, sandstone, much of the cancerous samples, each experiment has a 40 per category, each of which 30 were used to analyze the data collected. That degree of rock weathering, the rock, depending on the strength of the Intensity values can change, depending on the level of thermal imaging camera, also weathered the changes in temperature could see. Intensity is the strength of weak rocks, the more value decrease, the temperature of the thermal imaging camera through the swell Intensity and notice that the temperature had an inverse relationship. Intensity value of the low strength of weak rock, but the value came out of the rocks have been proved to be largely dependent on the contrast. The contrast of the surface rocks are weathered dark Intensity values lower temperature to swell the contrary, the degree of weathering can be distinguished.

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.82-87
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• 2011

Heat transfer oils are used in applications such as heating systems of chemical plant, refinery heat exchange systems, gas plant process, injection molding systems, and pulp and paper processing. These oils are extremely stable and resistance to thermal and oxidative degradation. In the event of a spill or accidental release of heat transfer oils, it can be ignite easily when there is an ignition source. This paper discusses the flammability and thermal stabilities of new and used oils. The flammability of the oils are assessed by measuring changes in flash point and auto ignition temperature. The thermal stability of oils are evaluated by the thermal screening unit ($TS^u$) and the differential scanning calorimeter (DSC). From the experimental results, it is suggested to give fire hazard characteristics to safe precautions for the proper use and treatment of heat transfer oils.

• Fire Science and Engineering
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• v.34 no.3
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• pp.28-34
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• 2020

In this study, an ISO 5660-1 cone calorimeter experiment was conducted to examine the effects of changes in flow and thermal thickness around solid combustibles on heat release rate characteristics. Polymethyl methacrylate (PMMA) is a solid combustible material that does not generate char during the combustion reaction. Hence, it was selected for the experiment, and the thermal penetration depth was calculated to distinguish the thermal thickness of PMMA. Furthermore, the thermal decomposition characteristics were analyzed by measuring the heat release rate measured during the combustion of PMMA. This was performed after generating the forced flow around the combustibles by setting the duct flow of the cone calorimeter to 12, 24, and 40 L/s. The results confirmed that the thermal release rate of the thermally thin combustible material was not significantly affected by the change in the surrounding flow. Hence, the thermally thick combustible material was significantly affected by the change in the flow rate.

• Journal of Korean Society of Steel Construction
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• v.10 no.1 s.34
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• pp.1-10
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• 1998

The temporary steel bridges which are constructed for detour and constructional expediency are consisted of H-beams(as superstructure) and H-piles(as substructure). Because these members are fastened by high-tension bolts, there are no expansion joints in these bridges. So, these kinds of bridges have no system which can relieve the excessive thermal stress. In this investigation, monitoring system was set up at temporary steel bridge and stress and temperature changes of H-beam are monitored. From these measured data, it is analyzed that the relationship between ambient and main-girder temperature change, between temperature and stress change. With these analyses, it is resulted that the thermal stress take main part of stress variation in this bridge and the restrain of thermal longitudinal displacement of H-pile. In addition, because the connection part of H-beam to H-beam is weak in the continuous spans, the sub-modelling is well apt to reflect the effect of thermal stress.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.1
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• pp.17-23
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• 2021

The membrane-type Liquefied Natural Gas (LNG) cargo tank is equipped with a double barrier to seal the LNG, of which the secondary barrier serves to prevent LNG leakage and mainly uses fiber-reinforced composite materials. However, the composite materials have thermal expansion anisotropy, which deteriorates shape distortion and mechanical performance due to repeated thermal loads caused by temperature changes between cryogenic and ambient during the unloading of LNG. Therefore, in this study, the longitudinal thermal expansion characteristics of the composite materials were obtained using a vertical thermo-mechanical analyzer, and the elastic modulus was obtained through the tensile test for each temperature to perform thermal load analysis for each direction. This is considered that it is useful to secure reliability from the viewpoint of the design of materials for a LNG cargo hold.

• Animal Bioscience
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• v.34 no.7
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• pp.1235-1242
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• 2021

Objective: The purpose of this study was to identify through infrared thermal imaging technology the facial surface temperature (FST) of laying hens in response to the variations in their thermal environment, and to identify the regional differences in FST to determine the most stable and reliable facial regions for monitoring of thermoregulatory status in chickens. Methods: Thirty Hy-Line Brown hens (25-week-old) were sequentially exposed to three different thermal conditions; optimal (OT, 22℃±2℃), low (LT, 10℃±4℃), and high temperature (HT, 30℃±2℃). The mean values of FST in five facial regions including around the eyes, earlobes, wattles, beak and nose, and comb were recorded through infrared thermography. The maximum FST (MFST) was also identified among the five face-selective regions, and its relationship with temperature-humidity index (THI) was established to identify the range of MFST in response to the variations in their thermal environment. Results: Hens exposed to OT condition at 15:00 displayed a higher temperature at wattles and around the eyes compared to other regions (p<0.001). However, under LT condition at 05:00 to 08:00, around the eyes surface temperature showed the highest value (p<0.01). In HT, wattles temperature tended to show the highest temperature over almost time intervals. Main distribution regions of MFST were wattles (63.3%) and around the eyes (16.7%) in OT, around the eyes (50%) in LT, and wattles (62.2%) and comb (18.3%) in HT. The regression equation between MFST and THI was estimated as MFST = 35.37+0.2383×THI (R² = 0.44; p<0.001). Conclusion: The FST and the frequency of MFST in each facial region of laying hens responded sensitively to the variations in the thermal environment. The findings of this experiment provide useful information about the effect of the thermal conditions on the specific facial regions, thus offering an opportunity to stress and welfare assessment in poultry research and industry.

• Fashion & Textile Research Journal
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• v.23 no.2
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• pp.261-272
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• 2021

The purpose of the present study was to evaluate the thermal insulation of air-filled winter jackets according to the amount of air-filler using a thermal manikin. The insulation of these jackets' was compared to a down padded jacket with an identical design and size. The amounts of air-filler were 100% (26,219 cm³), 70% (18,645 cm³), 50% (13,110 cm³), and 0% (0 cm³). The results showed that a clothing insulation (Icl) of 0%, 50%, 70%, and 100% air, and 100% down jackets was 0.208, 0.243, 0.207, 0.176, and 0.315 clo, respectively. In addition, the down jacket with waisttaped had a clothing insulation of 0.369 clo. However, the highest value of clothing insulation per clothing weight was the 50% air-filled jacket in all conditions. In terms of regional power consumption of the thermal manikin, the down jacket consumed less power for the shoulder and chest than the air-filled jackets. In conclusion, in order to maximize the thermal insulation of air-filled jackets, an optimal amount of air-filler, that is, an amount which does not compromise (break) the layer of inner air between the surface of manikin and the lining of the jacket, should be explored. Further studies on lining materials, end-closed design, and changes in thermal insulation under the conditions of strong wind or heavy snow are recommended.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.515-527
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• 2013

Building energy simulations which are mainly used in Korea have evaluated the building energy performance with the different thermal conductivity of construction materials. In order to evaluate the energy consumption accurately, the difference in thermal conductivity of the wood used in stud for wooden structure was confirmed from the each simulation. In addition, the thermal transmission of building members and the thermal bridge at the conjunction of building members according to thermal conductivity from each simulation programs were researched. The thermal conductivity of pine that has the largest variation among the energy simulations was applied to the thermal properties of studs in wooden structure. The maximum error between the maximum and minimum thermal transmission of roof, wall, and floor slab was $0.023W/m^2{\cdot}K$. Plus, that thermal bridge at Rafter junction on the roof, roof-wall joint, and floor slab-wall joint was $0.025W/m{\cdot}K$. The heat transfer image for changes in temperature and the heat exchange were analyzed by HEAT2 program. The distorted temperature lines were found around the insufficient insulated connection parts. It was predicted that the temperature at the distorted parts in the analyzed image was lower than that of the other portion of the other structures.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.106-108
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• 2007