• Title/Summary/Keyword: Temperatures

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Sex Ratios of Juveniles Hatched by Constant Temperatures Artificial Incubation From Eggs Collected in the Natural Nest of Soft-Shelled Turtle, Trionyx sinensis Strauch (1862) (한국산 자라, Trionyx sinensis (1862)의 자연산란둥지에서 수거한 난들의 항온인공부화에 의해 출생한 새끼자라들의 성비)

  • KIM, Sung Han
    • Journal of Fisheries and Marine Sciences Education
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    • v.29 no.3
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    • pp.702-710
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    • 2017
  • Recently, in many reptiles (14 genera of turtles in five families), common characteristics of incubation temperatures are known to determine the sexes of hatchlings in many species of turtles, including the map turtles, painted turtles and snapping turtles, emys turtle, etc. According to many researcher's reports, in general, incubation at $25^{\circ}C$ (cooler temperatures) produces all or mostly males, however, incubation at $31^{\circ}C$ (higher temperatures) or higher produces all or mostly females. Exceptionally, even cooler temperature ($20^{\circ}C$) produce females, they produced all or mostly females. Accordingly, it is well-known that incubation temperature is the sex determining agent in these turtles. However, this paper presents study of the sex ratio and nest ecology in natural spawning nest: Observations on hatching sex ratios of eggs collected from natural nests of T. sinensis are similar to a previous report of the same genus Trionyx in the soft-shelled turtles. However, this genus (or species) showed some different phenomena to other kinds of turtles such as various kinds turtles mentioned above. After collection of naturally spawned eggs (17 eggs of T. sisnensis) on the natural nests, a laboratory experiment by the constant incubation temperatures was conducted with natural fluctuating soil temperatures in the natural nest with the soft-shelled turtle, T. sinensis. And also laboratory experiments were conducted using constant incubation temperatures of $25^{\circ}C$ (cooler temp.) and $30^{\circ}C$ (higher temp.) with the turtle, T. sinensis. Exceptionally, it was confirmed that the first and second incubation temperatures can't control sex-determination in the freshwater soft-shelled turtle, T. sinensis. The sex ratio approximated 1:1 (${\chi}^2=0.06$, P>0.05 (the Ist experiment). And the sex ratio approximated 1:1 independently of incubation temperature (${\chi}^2=0.33$, P>0.05 (the 2nd experiment). Consequently, temperature has no effect on sex determination in the genus Trionyx in a soft-shelled turtle.

A Study on the Temperature Characteristics at the Inlet and the Outlet Pipes of a Refrigerator Drain Condenser (냉장고 배출수 응축기 입출구 배관에서의 온도 특성에 관한 연구)

  • Ha, Ji Soo;Kim, Tae Kwon
    • Journal of Energy Engineering
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    • v.23 no.4
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    • pp.247-255
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    • 2014
  • The present study was conducted to elucidate the characteristics of temperature at the inlet and outlet pipes of a refrigerator drain condenser and suggest the method to predict the temperature of the refrigerant at the inlet and outlet pipes of the drain condenser. For this purpose, a built in style refrigerator was installed in a constant temperature chamber to measure temperatures at the inlet and outlet pipes of the drain condenser. From the results of the present analysis, it could be seen that the measured temperatures changed from $37^{\circ}C$ to $46^{\circ}C$ and the actual refrigerant temperatures were higher than the measured temperatures with the difference magnitude of $8^{\circ}C$ to $22^{\circ}C$. The present study suggested that the temperatures of the refrigerator could be calculated with the measured temperatures by introducing curve fitting of the measured temperature. The predicted refrigerant temperatures by the present study had the accuracy within 6% error of the actual refrigerant temperatures.

Effects of Mold Temperatures on Physical Properites of Injection Molded Thermoplastic Polyurethanes (사출성형 열가소성 폴리우레탄의 물리적 성질에 미치는 금형 온도 영향)

  • Lee, Dai-Soo;Kim, Seong-Geun;Nguyen, Vinh-Khanh;Lee, Wing-Ji;Pang, Su-Jin
    • Elastomers and Composites
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    • v.39 no.4
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    • pp.286-293
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    • 2004
  • Ester- and ether-based thermoplastic polyurethanes of different hardness were injection molded at different mold temperatures and effects of mold temperature on the physical properties of TPUs were investigated. Glass transition temperatures of soft segments of TPUs were hardly changed by mold temperatures. The phase separation of soft and hard segments of injection molded TPUs were affected little by mold temperatures. However, crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength of injection molded TPUs decreased with increasing mold temperatures for TPUs of high hardness. However, injection molded TPUs of low hardness showed increases of crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength with increasing mold temperatures. Different physical properties of injection molded TPUs depending on mold temperatures were attributed to different crystallization and physical crosslinking effects of hard segments.

Oxygen Permeability Measurement of $ZrO_2-TiO_2-YB_2O_3$ Mixed Conductor

  • Hitoshi Naito;Kim, Hitoshi ishima;Toru Takahashi;Hiroo Yugami
    • The Korean Journal of Ceramics
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    • v.6 no.2
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    • pp.124-128
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    • 2000
  • Electrical properties of $ZrO_2-TiO_2Yb_2O_3$mixed conductor (Ti-YbSZ) were investigated. This mixed conductor can be applied as a membrane for gas separation at high temperatures. The total conductivity decreased with increasing the $TiO_2$concentration. At high temperatures, the rate of the conductivity degradation became smaller than that at low temperatures. From the oxygen partial pressure dependence of the total conductivity of Ti-YbSZ, the electronic conductivity increased with increasing $TiO_2$concentration at low oxygen partial pressures and at high temperatures. Both 15 and 20 mol% $TiO_2$doped YbSZ showed high oxygen permeability. Mixed conductors, which has high $TiO_2$concentration in YbSZ, are promising materials for using as a membrane for gas separation at high temperatures.

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Quality Characteristics of Yackwa Baked and Dipping with Goami Powder (굽기와 집청 조건에 따른 고아미 구운 약과의 품질 특성에 미치는 영향)

  • Kim, Hyun-Ah;Lee, Kyung-Hee
    • Journal of the East Asian Society of Dietary Life
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    • v.22 no.5
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    • pp.604-612
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    • 2012
  • The quality characteristics of yackwa made with goami powder at different baking temperatures (150, 160, 170, 180) and baking times (15, 20, 25 min) and at different dipping temperatures (65 and $80^{\circ}C$) and dipping times (15 and 30 min) were evaluated. To determine the optimal temperature and time for yackwa containing goami powder, color values, preference color and pictures were determind. The baking temperatures were $150^{\circ}C$ for 25 min, $160^{\circ}C$ for 15 min and 20 min, and $170^{\circ}C$ for 15 min. The weight of yackwa was heavier at low dipping temperatures and long dipping times. L-values and b-values were the highest at short dipping times. Hardness, moisture and overall preference was the lowest at low dipping temperatures and long dipping times.

Unsteady heat exchange at the dry spent nuclear fuel storage

  • Alyokhina, Svitlana;Kostikov, Andrii
    • Nuclear Engineering and Technology
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    • v.49 no.7
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    • pp.1457-1462
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    • 2017
  • Unsteady thermal processes in storage containers with spent nuclear fuel were modeled. The daily fluctuations of outer ambient temperatures were taken into account. The modeling approach, which is based on the solving of conjugate and inverse heat transfer problems, was verified by comparison of measured and calculated temperatures in outer channels. The time delays in the reaching of maximal temperatures for each spent fuel assembly were calculated. Results of numerical investigations show that daily fluctuation of outer temperatures does not have a large influence on the maximal temperatures of stored spent fuel, so that fluctuation can be neglected and only daily average temperature should be considered for safety estimation using the "best estimation" approach.

A Molecular Dynamics Study of the Interaction of Oxygen Molecules with a Water Droplet

  • Ambrosia, Matthew Stanley
    • Journal of Environmental Science International
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    • v.27 no.10
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    • pp.901-906
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    • 2018
  • Water and oxygen are two of the most essential molecules for many species on earth. Their unique properties have been studied in many areas of science. In this study, the interaction of water and oxygen molecules was observed at the nano-scale. Using molecular dynamics, a water droplet with 30,968 water molecules was simulated. Then, 501 oxygen molecules were introduced into the domain. A few oxygen molecules were attracted to the surface of the water droplet due to van der Waals forces, and some oxygen molecules actually entered the water droplet. These interactions were visualized and quantified at four temperatures ranging from 280 to 370 K. It was found that at high temperatures, there was a higher possibility of the oxygen molecules penetrating the water droplet than that at lower temperatures. However, at lower temperatures, oxygen molecules were more likely to be found interacting at the surface of the water droplet than at high temperatures.

An Experimental Study on the Low-Temperature Behavior of Stratified Fluids in the Square Cavity (저온에서 정방형 공간내 성층화된 유체의 열적거동에 관한 실험적 연구)

  • 강한용;이동석;김병철
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.4
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    • pp.381-387
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    • 2000
  • An experimental study on the stratified fluids was carried out to investigate the flow characteristics, heat transfer through the interface of fluids, and the applications of thermal behaviors in the square cavity. The same volume of water and silicon oil was filled in it. The experiments were performed with the variations of initial temperatures and cooling surface temperatures. And the effect of vertical or horizontal cooling surface positions in the square cavity was investigated. When the cooling surface temperatures were $-4^{\circ}C$ , the supercooling phenomena were observed for both cases of cooling surface positions in the full region regardless of the initial temperature of fluid. In the square cavity with horizontal cooling surfaces, the lower the initial temperatures were, the longer the supercooling durations were, and with vertical cooling surface the lower the initial temperatures were, the shorter the supercooling durations were.

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A study on the GaAs MESFET′s noise characteristics with temperature dependency (온도변화에 따른 GaAs MESFET′s 노이즈 특성 연구)

  • 김시한;이명수;박지홍;안형근;한득영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.322-325
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    • 2002
  • In this study, noise figures of 0.3 $\mu\textrm{m}$-GaAs MESFETs are predicted experimentally with different temperatures. Both the noise figure and the gate leakage current are obtained with wide range of temperatures(27$^{\circ}C$∼300$^{\circ}C$). From the results, gate leakage current increases with temperatures. It is expected that gate leakage current contributes directly to the increase of shot noise current. It is therefore highly recommended to apply an accurate noise analysis to the design of the devices and modules at high temperatures. Fini,Uy the relation between the gate currents resulting in the increase of noise and the noise figures of submicron GaAs MESFETs are traced with different temperatures

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Variation of Plant Temperature at Joining Parts of Grafted Watermelon Seedlings Graft-taken under Different Light Quality (상이한 광질하에서 활착된 수박 접목묘 결합 부위의 식물체온 변화)

  • Kim, Y.H.;Lee, S.H.
    • Journal of Biosystems Engineering
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    • v.31 no.5 s.118
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    • pp.449-453
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    • 2006
  • Effect of light quality on plant temperatures at joining parts of grafted watermelon seedlings was investigated using a thermal imaging system in this study. Plant temperatures at joining parts lowered than those at stem region during graft-taking. However, difference in plant temperatures at joining parts and at stem region decreased by days after graft-taking. Plant temperatures of grafted seedlings graft-taken under white, blue, red, and blue + red fluorescent lamps repeatedly fluctuated high at photoperiod and low at dark period. Considering the variation of plant temperatures at joining pa퍼5, the illumination of blue and red light as well as white light will be effective for grafting of grafted watermelon seedlings. It is recommended that air temperature around grafted seedlings should be maintained at 27 to $29^{\circ}C$ for enhancing the physiological reaction of callus and for the smooth joining of scion and rootstock.