• Communications of the Korean Mathematical Society
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• 제30권4호
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• pp.505-513
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• 2015

The present paper deals with the determination of displacement and thermal stresses in a semi-infinite circular cylinder defined as $0{\leq}r{\leq}b$, $0{\leq}z<{\infty}$, due to internal heat generation within it. A circular cylinder is considered having arbitrary initial temperature and subjected to time dependent heat flux at the fixed circular boundary (r = b) whereas the zero temperature at the lower surface (z = 0) of the semi-infinite circular cylinder. The governing heat conduction equation has been solved by using integral transform method. The results are obtained in series form in terms of Bessel functions. The results for displacement and stresses have been computed numerically and illustrated graphically.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.221-226
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• 2008

A typical unsteady internal ballistic analysis model was proposed to take account the erosive burning with the variance of local velocity and pressure along grain surface to the axis of a solid rocket combustor. The model introduced in this study showed good agreements with the results of previous research. It was investigated that the combustion pressure, grain length, initial temperature, and vaporization temperature of propellant affect on the erosive burning.

• Journal of the Korean Society of Propulsion Engineers
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• 제13권2호
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• pp.17-25
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• 2009

A typical unsteady internal ballistic analysis model was proposed to take account of the erosive burning with the variance of local velocity and pressure along the grain surface of a solid rocket combustor. To validate the model of concern in the study, both cases of non-erosive and erosive burning were compared with the previous researches with marginal accuracy. It was quantitatively investigated that the combustion pressure, grain length, initial temperature, and vaporization temperature of propellant affect the erosive burning characteristics.

• Structural Engineering and Mechanics
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• 제82권2호
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• pp.259-270
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• 2022

The paper investigates the residual stresses arising in a thermoviscoelastic cylinder as a result of layer-by-layer deposition of material on its lateral surface. Internal stresses are caused by incompatible deformations that accumulate in the assembly as a result of joining parts with different temperatures. For the analysis of internal stresses, an analytical solution to the axisymmetric quasi-static problem of thermoelasticity for a growing cylinder is constructed. It is shown that the distribution of residual stresses depends on the scenario of the surfacing process. In this case, the supply of additional heat to the growing body can significantly reduce the unevenness of temperature fields and reduce the intensity of residual stresses. The most effective is uneven heating, which can be realized, by the action of an alternating current with a tunable excitation frequency. The temperature and residual stresses fields on the growing surface is analyzed numerically for Titanium and Copper materials.

• Journal of the Korean Society of Clothing and Textiles
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• 제20권5호
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• pp.870-876
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• 1996

Microcapsules containing 2,4,4'-trichloro-2-hydroxydiphenyl ether (DP) and perfumes were prepared by the coacervation using poly (vinyl alcohol) and crosslinking agents. Internal phase content, percent releasing of core materials, antimicrobial activities of microcapsules and fabrics treated with them were investigated. The internal content of microcapsules containing perfumes and DP are increased with increasing perfumes. The internal content of cacharia in the microcapsue was higher than that of lemon and its maimum value was 93%. The microcapsules containing perfumes and DP did not release cacharia and lemon at roonl temperature. But the amount of perfumes released from microcapsules were increased with temperature and time of microcapsules containing DP and perfumes showed 100% reduction percentage of bacteria. The size of obstruction of fabrics treated with microcapsule containing DP and perfumes were increased with DP content in microcapsules.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2069-2087
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• 2023

In nuclear power plant (NPP) accidents, the containment is subject to high temperatures and high internal pressures, which may further trigger serious chain accidents such as core meltdown and hydrogen explosion, resulting in a significantly higher accident level. Therefore, studying the mechanical performance of a containment under high temperature and high internal pressure is relevant to the safety of NPPs. Based on similarity principles, the 1:3.2 scale model of a prestressed concrete containment vessel (PCCV) of a NPP was designed. The loading method, which considers the thermal-pressure coupling conditions, was used. The mechanical response of the PCCV was investigated with a simultaneous increase in internal pressure and temperature, and the failure mechanism of the PCCV under thermal-pressure coupling conditions was revealed.

• Microbiology and Biotechnology Letters
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• 제15권5호
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• pp.356-360
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• 1987

Effects of temperature on sisomicin fermentation were investigated. From the specific growth rates for logarithmic phase estimated at various temperatures, 8.2 kcal/g-mol was obtained as an activation energy for cell growth. It suggests that cell growth rate was limited by the internal diffusion layers for nutrients or oxygen caused by aggregated cells. Final antibiotic titer was decreased with in-creasing temperature, and it depended highly on the temperature to which cells were exposed during the logarithmic phase of growth. Temperature shifts during fermentation brought about an increase in antibiotic productivity.

• Korean Journal of Materials Research
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• 제17권5호
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• pp.268-272
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• 2007

Inconel 617 is a candidate tube material for high temperature gas-cooled reactors(HTGR). The microstructure and mechanical properties of Inconel 617 were studied after exposure at high temperature($1050^{\circ}C$). The dominant oxide layer was Cr-oxide. The internal oxide and Cr-depleted region were observed below the Cr-oxide layer. The depth of Cr-depleted zone and internal oxide increased with exposure time. The major phases of carbides are $M_{23}C_6\;and\;M_6C$. The composition of $M_{23}C_6\;and\;M_6C$ were determined to be Cr-rich and Mo-rich, respectively. $M_6C$ carbide is more stable than $M_{23}C_6$ at high temperature. From the results of high temperature compression test, there were no significant changes in hardness and yield strength upon increasing exposure time.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제16권9호
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• pp.6432-6438
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• 2015

In this paper, we analyzed by measuring the temperature and humidity inside of the Feed Bin, NV, EA, SA, $SA{\cdot}EA$, by applying the ventilation system offers an efficient management of the operating direction. In the period the target is not input and feed period to make a change in the Feed Bin within the temperature and humidity of the outdoor air temperature and relative humidity compared to accept the ventilation system. Internal temperature over a comparison of the external temperature and the relative humidity is $SA{\cdot}EA$, internal humidity can verify the efficiency and NV, SA ventilation applied.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3928-3942
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• 2022

Thermal striping is a complex thermal-hydraulic phenomenon caused by fluid temperature fluctuations that can also cause high-cycle thermal fatigue to the structural wall of sodium-cooled fast reactors (SFRs). Numerical simulations using large-eddy simulation (LES) were performed to predict and evaluate the characteristics of the temperature fluctuations related to thermal striping in the upper internal structure (UIS) of the prototype generation-IV sodium-cooled fast reactor (PGSFR). Specific monitoring points were established for the fluid region near the control rod driving mechanism (CRDM) guide tubes, CRDM guide tube walls, and UIS support plates, and the normalized mean and fluctuating temperatures were investigated at these points. It was found that the location of the maximum amplitude of the temperature fluctuations in the UIS was the lowest end of the inner wall of the CRDM guide tube, and the maximum value of the normalized fluctuating temperatures was 17.2%. The frequency of the maximum temperature fluctuation on the CRDM guide tube walls, which is an important factor in thermal striping, was also analyzed using the fast Fourier transform analysis. These results can be used for the structural integrity evaluation of the UIS in SFR.