• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.245-246
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• 2011

In recent research in this emerging and latent heat storage material features an innovative temperature - controlled Phase Change Materials to evaluate the superior thermal performance would like to calculate the thermal conductivity. Specified in KS F 4040 test specimen dimensions were equivalent in specifications, test methods according to KS L 9016 was an experiment in progress. As a result, the thermal conductivity of plain cement mortar mixed with more PCM came out with low thermal conductivity of mortar, thermal performance was excellent.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.396-400
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• 2003

This paper has studied thermal characteristics of machine tool to develope high speed spindle and optimum design condidering the thermal deformation. Comparing the test data of temperature measurement and structural analysis data using FEM, we verifiedthe test validity and predicted thermal deformation, influence of spindle generation of heat, and established cooling system to prevent the thermal deformation. 1) The temperature rise of spindle system depends on increasing number of rotation and shows sudden doubling increment of number of rotation over 7,000rpm. 2) Oil jacket cooling can be effective cooling method below 8,000rpm but, over 8,000rpm, it shows the decrement of cooling effect. 3) Comparing FEM analysis results and revolution test results, we can confirmn approximate temperature change consequently, it is possible to simulate temperature rise and thermal distribution on the inside of spindle system. 4) We can confirm that simulated approach by FEM analysis can be effective method in thermal-appropriate design..

• Solar Energy
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• v.9 no.1
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• pp.22-29
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• 1989

A simulation model of plastic greenhouse was developed to evaluate the insulation effect of thermal curtain. Change in thermal environment with and without thermal curtain was verified through experiments, which agreed with the predicted values satisfactorily. About 18 to 20% of energy was saved in the plastic greenhouse by employing the P.E. film thermal curtain. Employing P.E. film thermal curtain also raised the temperature of the covering film and inner air by $1^{\circ}C$ and $1.5{\sim}1.8^{\circ}C$, respectively.

• Journal of the Korean Solar Energy Society
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• v.29 no.5
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• pp.20-27
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• 2009

The effect of borehole thermal resistance on the borehole length is studied. In performing this work a new concept BLRR(borehole length reduction rate) is developed based on the line source model. The solution of line source model is shown to be valid through the comparison with the data of thermal response test. It is shown that BLRR is a function of soil thermal conductivity(k) and borehole thermal resistance($R_b$). The value of BLRR increases with increasing k, which means reducing $R_b$ is more effective when k is high. The reduction of borehole length with change of $R_b$ is easily estimated with BLRR. The validity of BLRR is also examined with EED analysis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.980-984
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• 2002

This paper has studied thermal characteristics of machine tool to develope high speed spindle and optimum design condidering the thermal deformation. Comparing the test data of temperature measurement and structural analysis data using FEM, we verified the test validity and predicted thermal deformation, influence of spindle generation of heat, and established cooling system to prevent the thermal deformation. 1) The temperature rise of spindle system depends on increasing number of rotation and shows sudden doubling increment of number of rotation over 7,000rpm. 2) Oil jacket cooling can be effective cooling method below 8,000rpm but, over 8,000rpm, it shows the decrement of cooling effect. 3) Comparing FEM analysis results and revolution test results, we can confirm approximate temperature change consequently, it is possible to simulate temperature rise and thermal distribution on the inside of spindle system. 4) We can confirm that simulated approach by FEM analysis can be effective method in thermal-appropriate design.

• Ceramist
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• v.22 no.4
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• pp.393-401
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• 2019

Thermal analysis means the analysis of a change in a property of a sample, which is related to an imposed temperature alteration. Measurements are usually made with increasing temperature, but isothermal measurements or measurements made with decreasing temperatures are also possible. In fact, any measuring technique can be made into a thermal analysis technique by adding thermal control. Simultaneous use of multiple techniques increases the power of thermal analysis, and modern instrumentation has permitted extensive growth of application. The basic theories of thermal analysis are well developed and some of them are explained in this paper.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1181-1186
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• 2000

The crack of concrete induced by the heat of hydration is a serious problem, particularly in concrete structures such as biers, thick walls, box type walls, mat-slab of nuclear reactor buildings, dams or foundations of high rise buildings, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, design change which considers steel bar reinforcement, operation control and so on. In this study, firstly it introduce the thermal cracks control technique by employing low-heat cement concrete, thermal stress analysis considering season. Secondly it shows the application of the cracks control technique like block placement.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.498-503
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• 2002

This paper has studied thermal characteristics of machine tool to develope high speed spindle and optimum design considering the thermal deformation. Comparing the test data of temperature measurement and structural analysis data using FEM, we verified the test validity and predicted thermal deformation, influence of spindle generation of heat, and established cooling system to prevent the thermal deformation. 1) The temperature rise of spindle system depends on increasing number of rotation and shows sudden doubling increment of number of rotation over 7,000rpm. 2) Oil jacket cooling can be effective cooling method below 8,000rpm but, over 8,000rpm, it shows the decrement of cooling effect. 3) Comparing FEM analysis results and revolution test results, we can confirmn approximate temperature change consequently, it is possible to simulate temperature rise and thermal distribution on the inside of spindle system. 4) We can confirm that simulated approach by FEM analysis can be effective mettled in thermal-appropriate design.

• Advances in nano research
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• v.6 no.1
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• pp.57-80
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• 2018

In this study, the thermal loading effect on free vibration characteristics of carbon nanotubes (CNTs) with multiple cracks is studied. Various boundary conditions for nanotube are taken in to account. In order to take the small scale effect, the nonlocal elasticity of Eringen is employed in the framework of Euler-Bernoulli beam theory. This theory states that the stress at a reference point is a function of strains at all points in the continuum. A cracked nanotube is assumed to be consisted of two segments that are connected by a rotational spring which is located in the position of the cracked section. Hamilton's principle is used to achieve the governing equations. Influences of the nonlocal parameter, crack severity, temperature change and the number of cracks on the system frequencies are investigated. Also, it is found that at room or lower temperature the natural frequency for CNT decreases as the value of temperature change increases, while at temperature higher than room temperature the natural frequency of CNT increases as the value of temperature change increases. Various boundary conditions have been applied to the nanotube.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.106-112
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• 2013

Compression ratio is an important factor affecting engine performance and emission characteristics since thermal efficiency of spark ignition engine can be theoretically improved by increasing compression ratio. In order to evaluate the effect of compression ratio change in HCNG engine, natural gas engine was employed using HCNG30 (CNG 70 vol%, hydrogen 30 vol%). Combustion and emission characteristics of CNG and HCNG fuel was analyzed with respect to the change of compression ratio at each operating condition. The results showed that thermal efficiency improved and $CH_4$, $CO_2$ emission decreased with the increase in compression ratio while $NO_x$ emissions were decreased at a certain excess air ratio condition. Higher thermal efficiency and further reduction of exhaust emissions can be achieved by the increase of compression ratio and the retard of spark timing.