• Journal of Korean Society of Disaster and Security
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• v.9 no.2
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• pp.33-42
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• 2016

Domestic harbor yard storage facilities are a place specifically located in a container terminal for import and export of packaged dangerous goods, and due to the recent relaxed criteria for the secured open area, concerns for the extended damage upon accidents are increasing. In this study, the impact of damages by radiant heat was analyzed through a simulation of a pool fire caused by the leakage of flammable liquids from a tank container. As a result, it was analyzed that the distance of radiant heat according to threshold damage levels was beyond the current criteria of the secured open area, and the structural damage of adjacent containers could happen within a very short time if they were exposed to the early pool fire continuously. It is considered that this study will be helpful in preparing the proper criteria for the secured open area between yard storage facilities in a container terminal.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.1
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• pp.93-100
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• 2011

The thermal property of insulation material is essential in developing a high-temperature superconductor (HTS) power cable to be operated at around liquid-nitrogen temperature. Unlike metallic materials, nonmetallic materials have a high thermal resistance; therefore, accurate estimate of the heat flow is difficult in the case of nonmetallic materials. The aim of this study is to develop an instrument for precisely measuring the thermal conductivity of insulating materials over a temperature range of 30 K to approximately the room temperature by using a cryocooler. The details of the thermal-conductivity measurement system, including the design and fabrication processes, are described in this paper. In addition, the design optimization to minimize unavoidable heat leakage from room temperature is discussed.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.59-65
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• 2016

PURPOSES : This paper aims to develop a road pavement de-icing system using carbon sheet to replace the older snow de-icing method. Carbon sheet is a light and high-strength metal. Hence, various bodies of research for its applications in many industries have progressed. METHODS : The experiment was conducted in a laboratory. The carbon sheet supplied voltage through a power supply system, and produced heat transfers to the concrete surface. Various factors, such as pavement material, carbon sheet width, penetration depth, and freezing-thawing resistance, were considered in the conducted experiments to confirm the heating transfer efficiency of the carbon sheet. RESULTS : The carbon sheet used was a conductor. Therefore, it produced heat if voltage was supplied. The exposed carbon sheet on the atmosphere did not affect the carbon sheet width when it provided constant voltage. However, the sheet showed different heating behaviors by width change when the carbon sheet penetrated into the concrete. Moreover, the freezing-thawing resistance was decreased by the carbon sheet with increasing width. CONCLUSIONS : The experiments confirmed the possibility of developing a road snow melting system using a carbon sheet. The antiicing system using the carbon sheet to replace the traditional anti-icing system has disadvantages of environmental pollution risk and electric leakage. The pavement also improved its toughness resistance. The utilization value will be very high in the future if carbon sheet heat loss can be minimized and durability is improved.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1024-1029
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• 2009

According to increase of massive concrete structures, Thermal crack done by heat of hydration have been increased in a process of the execution. In case of a subway concrete box structure, thickness of structures are almost over 1 meter, and penetrating crack by external restraint takes a bad effect on the durability with a water leakage and deterioration in especially concrete wall. A try of shortening a constructing period often occurs as subway is generally constructed according to a road to decrease a traffic jam. The research proposes executing method by skipping one block as a plan of shortening a constructing period and investigate an influence on thermal cracking control. Additionally, sensitivity analysis is accomplished by changing a height of a concrete wall, and concrete placing and air temperature met with a field condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.555-559
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• 2011

Oil hydraulic piston pumps are extensively used worldwide because of their simple design, light weight, and cost effectiveness. However, an oil hydraulic pump is likely to have high leakage, friction, and low energy efficiency after long-term use. In oil hydraulic piston pumps the clearance between the valve block and the piston plays an important role in the volumetric and overall efficiency. We studied the wear property of the SACM645 material used in hydraulic piston pumps via experiments with different heat treatments. We prepared three different specimens. The maximum tensile strengths of the QT and QT-nitration specimens are similar (about 820 MPa), but the strains are significantly different. However, the fatigue characteristic depended on the heat treatment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.3
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• pp.39-48
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• 1989

The concrete temperature in mass concrete rises rapidly above the placing temperature owing to the heat given off by the hydrating cement. This temperature rise produces tensile stress and cracks which later become the cause of water leakage in concrete structures. It is essential, therefore, to reduce the interior heat of concrete dam given off by hydrating cement by artificial cooling. The present study aiming to study the temperature variations in mass concrete by pipe cooling, compars the actual measurements of Chungju Dam with the temperature calculated by Finite Difference Method(FDM), and it found that the results closely agree with each other. Based on these results, the analyses are performed simulate the interior temperature history of concerte dam made of type II (moderate heat) portland cement under various coditions.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.952-964
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• 2016

The prototype generation IV sodium-cooled fast reactor (PGSFR) has been developed by the Korea Atomic Energy Research Institute. This reactor uses sodium as a reactor coolant to transfer the core heat energy to the turbine. Sodium has chemical characteristics that allow it to violently react with materials such as a water or steam. When a sodium-water reaction (SWR) occurs due to leakage or breakage of steam generator tubes, high-pressure waves and corrosive reaction products are produced, which threaten the structural integrity of the components of the intermediate heat-transfer system (IHTS) and the safety of the primary heat-transfer system (PHTS). In the PGSFR, SWR events are included in the design-basis event. This event should be analyzed from the viewpoint of the integrities of the IHTS and fuel rods. To evaluate the integrity of the IHTS based on the consequences of the SWR, the behaviors of the generated high-pressure waves are analyzed at the major positions of a failed IHTS loop using a sodium-water advanced analysis method-II code. The integrity of the fuel rods must be consistently maintained below the safety acceptance criteria to avoid the consequences of the SWR. The integrity of the PHTS is evaluated using the multidimensional analysis of reactor safety-liquid metal reactor code to model the whole plant.

• Journal of muscle and joint health
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• v.18 no.2
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• pp.192-202
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• 2011

Purpose: This study examined the effects of heat therapy combined with aromatherapy on pain, flexibility, sleep, and depression in elderly women with osteoarthritis. Methods: This study was designed as a nonequivalent control group quasi-experimental study based upon data acquired through a pre-post test. The experimental group (n=21) was treated using an aroma-permeated hot compress applied to the knee. The cotton towel was heated in a microwave to $45^{\circ}C$, and 2~3 drops of lavender were applied on it. The towel was wrapped with plastic bag to prevent aroma leakage and retain heat. The treatment was applied the towel for 20 minutes, three times a day for 3 weeks. The control group (n=24) was not given any treatment. Data were collected using a VAS(100mm) for pain, questionnaire for sleep and depression, and a goniometer for knee flexibility. The data were analyzed with ${\chi}^2$-test and t-test using SPSS/Win18.0. Results: There were significant differences in knee pain (p=.001) and flexibility (p<.001), subjective quality of sleep (p=.020) and depression (p=.003) between the groups. Conclusion: Heat therapy combined with aromatherapy may be an effective nursing intervention and self-care technique to ameliorate pain and depression and to improve flexibility and sleep in elderly suffering from osteoarthritis.

• Molecules and Cells
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• v.39 no.6
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• pp.477-483
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• 2016

Heat shock factors (Hsfs) are central regulators of abiotic stress responses, especially heat stress responses, in plants. In the current study, we characterized the activity of the Hsf gene HsfA3 in Arabidopsis under oxidative stress conditions. HsfA3 transcription in seedlings was induced by reactive oxygen species (ROS), exogenous hydrogen peroxide ($H_2O_2$), and an endogenous $H_2O_2$ propagator, 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB). HsfA3-overexpressing transgenic plants exhibited increased oxidative stress tolerance compared to untransformed wild-type plants (WT), as revealed by changes in fresh weight, chlorophyll fluorescence, and ion leakage under light conditions. The expression of several genes encoding galactinol synthase (GolS), a key enzyme in the biosynthesis of raffinose family oligosaccharides (RFOs), which function as antioxidants in plant cells, was induced in HsfA3 overexpressors. In addition, galactinol levels were higher in HsfA3 overexpressors than in WT under unstressed conditions. In transient transactivation assays using Arabidopsis leaf protoplasts, HsfA3 activated the transcription of a reporter gene driven by the GolS1 or GolS2 promoter. Electrophoretic mobility shift assays showed that GolS1 and GolS2 are directly regulated by HsfA3. Taken together, these findings provide evidence that GolS1 and GolS2 are directly regulated by HsfA3 and that GolS enzymes play an important role in improving oxidative stress tolerance by increasing galactinol biosynthesis in Arabidopsis.

• Geomechanics and Engineering
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• v.18 no.2
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• pp.189-203
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• 2019

Brine leakage is a common phenomenon during construction facilitated by artificial freezing technique, threatening the stability of frozen wall due to the continual thawing of already frozen domain. This paper takes the frequently encountered soft clay in Wujiang District as the study object, and remolded specimens were prepared by mixing calcium chloride solutions at five levels of concentration. Both the deformation and pore water pressure of frozen specimens during thawing were investigated by two-stage loading tests. Three sections were noted from the changes in the strain rate of specimens during thawing at the first-stage load, i.e., instantaneous, attenuated, and quasi-stable sections. During the second-stage loading, the deformation of post-thawed soils is closely correlated with the dissipation of pore water pressure. Two characteristic indexes were obtained including thaw-settlement coefficient and critical water content. The critical water content increases positively with salt content. The higher water content of soil leads to a larger thaw-settlement coefficient, especially at higher salt contents, based on which an empirical equation was proposed and verified. The normalized pore water pressure during thawing was found to dissipate slower at higher salt contents, with a longer duration to stabilize. Three physical indexes were experimentally determined such as freezing point, heat conductivity and water permeability. The freezing point decreases at higher salt contents, especially as more water is involved, like the changes in heat conductivity. The water permeability maintains within the same order at the considered range of salt contents, like the development of the coefficient of consolidation. The variation of the pore volume distribution also accounts for this.