• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.119-123
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• 2000

Effect of fluctuating temperatures on the development of the immature beet armyworm, Spodoptera exigua (H bner), was analyzed. At constant rearing temperature regimes, the estimated developmental threshold temperatures were varied among stages and instars, but had an average 13$^{\circ}C$ from egg hatch to adult emergence. Based on the 13$^{\circ}C$ threshold temperature, we set up three different rearing temperature regimes having the same day-degrees. Two fluctuating temperature regimes changed significantly the developmenta1 period expected by the constant rearing temperature regime. Under the same thermophase temperature (25$^{\circ}C$), the thermocycling regime with the higher cryophase temperature (10$^{\circ}C$) decelerated the developmental rate probably by lowering temperature limit thor development, but that with the lower cryophase temperature (5$^{\circ}C$) gave a negative developmental effect.

• Food Science and Biotechnology
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• v.14 no.3
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• pp.437-439
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• 2005

Freshness of stored soybean curd as sensitivity ($R_{gas}/R_{air}$) was evaluated at 48-50 hr intervals using electronic nose at regular sequential square-wave temperatures between $4\;-\;10^{\circ}C$. Obtained kinetic data from apparent first principal component score $(PC1)_{app}$ and storage time were used for prediction of freshness. Percentage difference between predicted and actual values of stored soybean curd was less than 8.9% under fluctuating temperature condition.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.3
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• pp.229-235
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• 2006

This study investigated physiology and psychological response of subjects, when heat pump was operated long time within comfort temperature range. Eight subjects were participated for the experiment. Their age was from 22 to 25 years old. The results of this experiment will propose basic data for improving comfort control algorithm in fluctuating environment by using heat pump. When indoor temperature was controlled by heat pump, the conclusion was as follows. 1) When votes of subjects was considered, the thermal comfort neutrality or lower range helped formation of comfort sensation for subjects. 2) When room temperature was lower, thermal comforts of shoulder, knee and foot with subjects thermal comfort showed high correlation. And when room temperature was higher, thermal comfort of face region with subjects thermal comfort showed high correlation. 3) The necessity of temperature change after 50 minutes from initially operating heat pump demands the additional analysis against the physiological signal.

• Journal of The Korean Astronomical Society
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• v.12 no.1
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• pp.27-34
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• 1979

Temperature history of very small interstellar dust particles is followed under diffuse interstellar radiation. Because of extremely small thermal capacities of these grains with sizes ranging from a few tens to hundred Angstroms in radii, they are to experience strong fluctuations in temperature whenever they are hit by interstellar ultraviolet photons. Fluctuating temperature can inhibit these smaller component of interstellar dust from growing into core-mantle particles of submicron sizes by continuously evaporating atoms and molecules adsorbed on their surface. This is interpreted as a possible physical reason for the bimodal nature in grain size distribution. A brief discussion is also given to the far infrared emission properties of such small grains in diffuse interstellar dust clouds.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.947-952
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• 1996

The effect of fluctuating temperature on the respiration of vegetables has been investigated. Spinach was selected as the experimental material because of its high respiratory activity and kept under the condition that temperature changed alternately at low and high levels every 4 hours. The low-high level temperature combination was set in $1-10^{\circ}C,{\;}1-20^{\circ}C{\;}and{\;}1-30^{\circ}C$. Respiration was evaluated in terms of quantity of $CO_2$ evolved from spinach. The evolution rate of $CO_2$ was determined by a change in its concentration. The evaluation rate of $CO_2$ followed closely the temperature change. In the temperature combinations at $1-10^{\circ}C{\;}and{\;}1-20^{\circ}C$, the relationship between $CO_2$ evolution rate and temperature was found to be able to express by Arrhenius law, while at $1-30^{\circ}C$, it did not obey the law.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.184-190
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• 2002

This study was undertaken to judge the quality of air-tightened exhibition cases. Exhibition cases for artifacts display provide a layer of protection between the interior conditions in the exhibition case and the exterior fluctuating conditions of temperature and relative humidity in the museum environment. An infiltration model of the exhibition case was developed through the experimental measurements to calculate the number of air change rate in the exhibition case undergoing in a day, which represents the airtightness of the exhibition case. The results indicate that tighter exhibition cases provide greater protection against the fluctuating conditions of temperature and humidity outside. When the temperature and humi- dity difference between the exhibition case in-and-out is larger, some absorption materials should be applied to control the environmental conditions in the exhibition case.

• The KSFM Journal of Fluid Machinery
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• v.18 no.4
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• pp.13-21
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• 2015

The system design of the Organic Rankine Cycle(ORC) is greatly influenced by the thermal properties such as the temperature or the thermal capacity of heat source. Typically waste heat, solar energy, geothermal energy, and so on are used as the heat source for the ORC. However, thermal energy supplying from these kinds of heat sources cannot be provided constantly. Hence, an experimental study was conducted to utilize fluctuating thermal energy efficiently. For this experiment, an impulse turbine and supersonic nozzles were applied and the supersonic nozzle was used to increase the velocity at the nozzle exit. In addition, these nozzles were used to adjust the mass flowrate depending on the amount of the supplied thermal energy. The experiment was conducted with maximum three nozzles due to the capacity of thermal energy. The experimented results were compared with the predicted results. The experiment showed that the useful output power could be producted from low-grade thermal energy as well as fluctuating thermal energy.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1661-1668
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• 1990

In a turbulent premixed flame stabilized by the streamline step, and dominated by a coherent eddy, a flame micro-structure was investigated with analyzing the signals of temperature, the ion current, and schieren phtographs simultaneously. Generally the contours of large scale coherent eddies of schlieren photographs was considered as the flame front, however, the main reaction can be occurred within the eddy as a structure of fine flamelets scale. The surrounding burned gas of flamelets could not propagate to a unburned mixture, obstructing flamelets from propagating to a unburned mixture. Consequently, it could restrain flashback. The main reaction region was found to be located at higher temperature of the burned gas rather than at maximum rms of fluctuating temperature. The peak probability of higher temperature was 6 times greater than that of lower temperature. As it was difficult to infer a flame structure from PDF distribution of the fluctuating temperature in form of bimodal shape, it should be taken into consideration with other informations related to the sensitive flame front, for instance, ion current.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.348-353
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• 2008

Aerobic bacterial growth on Korean pan.fried meat patties as a primary quality deterioration factor was modeled as a function of temperature to estimate microbial spoilage on a real.time basis under dynamic storage conditions. Bacteria counts in the stretch.wrapped foods held at constant temperatures of 0, 5, 10 and $15^{\circ}C$ were measured throughout storage. The bootstrapping method was applied to generate many resampled data sets of mean microbial counts, which were then used to estimate the parameters of the microbial growth model of Baranyi & Roberts in the form of differential equations. The temperature functions of the primary model parameters were set up with confidence limits. Incorporating the temperature dependent parameters into the differential equations of bacterial growth could produce predictions closely representing the experimental data under constant and fluctuating temperature conditions.

• Nuclear Engineering and Technology
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• v.54 no.10
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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.