• Title/Summary/Keyword: temperature effects

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Effects of Storage Environmental Conditions on Weight Loss, Whiteness Change, and Microbial Activity of Mushrooms (Agaricus bisporus)

  • Pai, Tongkun
    • Journal of Applied Biological Chemistry
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    • v.43 no.3
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    • pp.161-164
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    • 2000
  • The effects of storage temperature and high relative humidity (RH) on the weight loss, color change, and microbial activity of a mushroom ('Sylvan' hybrid white) were investigated. The experiment was performed at three temperature (5, 10 and $15^{\circ}C$) and four different relative humidity levels (91, 94, 97 and 99%). The weight loss of the tested samples had a highly correlated linear relationship with storage time at each RH level during storage. Both the storage temperature and RH levels in the experiment had signigicant effects (p<0.05) on the weight-loss rate of the tested samples. The loss whiteness of mushrooms was not significantly affected (p>0.05) by RH ranges at the same temperature. No visible damage was caused by either bacteria or fungi in all samples during storage.

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A Preliminary Analysis of the Impact of Urban Green Spaces on the Urban Heat Island Effect Using a Temperature Map

  • Myeong, Soo-Jeong
    • Korean Journal of Remote Sensing
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    • v.26 no.6
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    • pp.675-680
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    • 2010
  • Temperature is one of the main issues in climate change, and the urban heat island effect in highly developed urban areas is an important issue that we need to deal with. This study analyzed the extent of the cooling effects of urban green spaces. The study used a surface temperature map of Seoul. It found that the cooling effects of green space was observed within limited distances, although it varied a little depending on the parks investigated. The cooling effect distance ranged from 240m to 360m, averaging about 300m. It also found the size of an urban green space does not make much difference in cooling the surrounding areas. Although further investigation with diverse urban areas should be conducted on this matter, the results did imply that many small green spaces in the neighborhood are more effective than a single big green space in mitigating the heat island effects of cities.

Effects of longitudinal conduction on the performance of heat transfer surfaces (유동방향의 열전도가 전열면의 성능에 미치는 영향)

  • Park, Byung-Kyu;Hong, Taek;Park, Sang-Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.5
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    • pp.561-569
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    • 1999
  • The effects of longitudinal heat conduction on the performance of heat transfer surfaces are investigated by using a single-blow method. In the transient testing method for determining the heat transfer characteristics, exponential inlet temperature variations are made by using screen-mesh heater with small time constant and low frontal velocities of the test section, and the experimentally determined inlet temperature profile is used as the inlet fluid temperature condition. The effects of longitudinal heat conduction are negligible only if $\gamma^\act<0.05\;and \;N_{tu}\le3$ and should be considered if $N_{tu}\le3$ The test results ate compared with the existing theoretical and experimental data and the validity of this technique is confirmed by the good agreement.

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Effects of NaCl and Temperature on the Sensory Characteristics of Natural Flavor Enhancers (NaCl 첨가 및 평가 온도에 따른 천연조미소재의 감각적 특성)

  • Chung, Seo-Jin;Chung, JinA;Kim, BooWon;Kang, Deik
    • Korean Journal of Food Science and Technology
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    • v.47 no.5
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    • pp.615-622
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    • 2015
  • The objectives of this study were to evaluate the sensory properties of various natural flavor enhancers (NFEs) and to understand the effects of NaCl and temperature on the sensory characteristics of these NFEs. Descriptive analysis was conducted to evaluate six types of NFEs: yeast extract-based NFE, three; fish sauce-based NFE, one; soy sauce-based NFE, one; and hydrolyzed peptide NFE-based, one. The effects of NaCl (no addition vs. addition) and temperature ($20^{\circ}C$ vs. $55^{\circ}C$) were also evaluated. The results showed that the overall flavor intensity and sensory properties of the NFEs differed greatly depending on the NFE source. Two of the yeast extract-based NFEs elicited higher umami intensity than the other NFEs. Addition of NaCl increased some of the savory-related flavors and the perceived viscosity of the sample. Aroma intensities, in general, were enhanced at the higher temperature, whereas flavor, aftertaste, and mouthfeel attributes were perceived to be stronger at the lower temperature.

A Study of the Effects of Process Variables on Temperature and Magnetic-flux Distribution in Induction Heating of Steel Plate (강판의 유도가열에서 공정변수가 온도 및 자속분포에 미치는 영향에 관한 연구)

  • 배강열;이태환;양영수
    • Journal of Welding and Joining
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    • v.19 no.5
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    • pp.526-533
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    • 2001
  • Induction heating of float metal products has an increasing importance in many applications, because it generates the heat within workpiece itself and provides high power densities and productivity. In this study, the induction heating of a steel plate to simulate the line heating is investigated by means of the Finite Element Analysis of the magnetic field and temperature distribution. A numerical model is used to calculate temperature distribution within the steel plate during the induction heating with a specially designed inductor. The effects of materital properties depending on the temperature and magnetic field are taken into consideration in an iterative manner. The simulation results show good magnetic field with experimental data and provide good understanding of the process. Since the numerical model demonstrates to be suitable for analysis of induction heating process, the effects of air gap and frequency on magnetic-flux and power-density distribution are also investigated. It is revealed that these process parameters have an important roles on the electro-magnetic field and power-density distribution governing the temperature distribution of the plate.

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Parametric Study on the Design of Turbocharger Journal Bearing - Aeration Effects

  • Chun, Sang-Myung
    • KSTLE International Journal
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    • v.7 no.2
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    • pp.35-44
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    • 2006
  • Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure, then the friction and load of journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

Aeration Effects on the Performance of Turbocharger Journal Bearing under Constant Load Operating Condition (일정하중 운전조건 하에서 공기혼입이 터보챠져 저어널베이링의 성능에 미치는 영향)

  • Chun, Sang-Myung
    • Tribology and Lubricants
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    • v.23 no.5
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    • pp.207-218
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    • 2007
  • Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure distribution, then the friction in a journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

Environmental Change Uncovers Differences in Polygenic Effect of Chromosomes from a Natural Population of Drosophila melanogaster

  • Jeung, Min-Gull;Thompson, James-N.Jr;Lee, Chung-Choo
    • Animal cells and systems
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    • v.1 no.4
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    • pp.609-617
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    • 1997
  • Polygenic variation of sternopleural bristle number was investigated at the whole chromosome level in a natural population of Drosophila melanogasfer. Fifty pairs of second and third chromosomes were analyzed at $25^\circ{C}$. Since environmental factors such as temperature influence polygenic expression of quantitative traits, whole chromosomal effects of 28 pairs from the larger original sample were measured under cycling temperature, a $10-30\circ{C}$ cycle in 24 hours, to reveal any polygenic alleles whose effects might be masked under the constant temperature. While third chromosomes typically showed a larger contribution to polygenic variation in both environments, second chromosomes showed greater sensitivity to environmental changes. Cluster analyses of second and third chromosomes produced a limited number of clusters. Such a small number of cluster's implies that there may be a small number of genes, or quantitative trait loci (QTLs), having large effects on phenotypic variation. The genetic structure assessed under constant temperature, however, did not show any correlation with the structure under cycling temperature. The discrepancy could be caused by independent response of each polygenic allele to temperature changes. Thus, polygenic structure in natural populations should be thought of as a temporally changing profile of interactions between gene and ever-changing environment.

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Immediate Effects of Release Ball Massage and Self-stretching Exercise on Hamstring's Temperature, Range of Motion and Strength in 20's Women

  • Jeong, Younghun;Park, Jihwan;Yu, Jin;Lee, Sunyeong;Ha, Jihee;Choo, Yeonki;Oh, Taeyoung
    • Journal of International Academy of Physical Therapy Research
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    • v.10 no.1
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    • pp.1739-1745
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    • 2019
  • Background: There have been many studies on self-myofascial release (SMR) stretching, but there are few comparative studies on the effects of massages using a release ball, which is a type of the SMR method. Objective: To investigate the immediate effects of release ball massage and self-stretching on proprioceptive sensory, hamstring's temperature, range of motion (ROM) muscle strength,. Design: Crossover study. Methods: Thirty women in 20's at S University in Busan voluntarily participated in the study. Participants were random to release ball group (n=15) or self-stretching group (n=15). Both groups performed 3 sets of exercises, stretching for 30 seconds and resting for 15 seconds in each position. The proprioceptive sensory, temperature of the hamstring muscle, ROM, and strength were measured before exercise, 5 minutes after exercise, and 30 minutes after exercise. Results: Release ball group showed significant differences in muscle length and temperature over time (p<.05). The comparison between two group over time showed significant differences in muscle length, temperature, and muscle strength (p<.05). Conclusions: These results demonstrate that release ball massage and self-stretching are beneficial for improving hamstring's temperature, ROM and muscle strength.

Effects of gamma aminobutyric acid on performance, blood cell of broiler subjected to multi-stress environments

  • Keun-tae, Park;Mihyang, Oh;Younghye, Joo;Jong-Kwon, Han
    • Animal Bioscience
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    • v.36 no.2
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    • pp.248-255
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    • 2023
  • Objective: Stress factors such as high temperatures, overcrowding, and diurnal temperature range exert profound negative effects on weight gain and productivity of broiler chickens. The potential of gamma aminobutyric acid (GABA) as an excitatory neurotransmitter was evaluated under various stress conditions in this study. Methods: The experiment was conducted under four different environmental conditions: normal, high temperature, overcrowded, and in an overcrowded-diurnal temperature range. The experimental groups were divided into (-) control group without stress, (+) control group with stress, and G50 group (GABA 50 mg/kg) with stress. Weight gain, feed intake, and feed conversion ratio were measured, and stress reduction was evaluated through hematologic analysis. Results: The effects of GABA on broilers in four experimental treatments were evaluated. GABA treated responded to environmental stress and improved productivity in all the experimental treatments. The magnitude of stress observed was highest at high temperature, followed by the overcrowded environment, and was least for the overcrowded-diurnal temperature range. Conclusion: Various stress factors in livestock rearing environment can reduce productivity and increase disease incidence and mortality rate. To address these challenges, GABA, an inhibitory neurotransmitter, was shown to reduce stress caused due to various environmental conditions and improve productivity.