• Journal of Animal Environmental Science
• /
• v.1 no.1
• /
• pp.39-45
• /
• 1995

Temperatures of blood and skin, respiratory rate and plasma cortisol concentration in sheep at a warm (average ambient temperature of $15.3^{\circ}C$) and a hot (average ambient temperature of $27.0^{\circ}C$ environment were measured to investigate the effect of hot environment on the physiological responses in ruminant. Temperatures of core, mean skin and mean body in sheep were tended to increase at day time and to decrease at night time at both warm and hot environment, while 24-hr average for those temperatures were significantly higher at hot environment than at warm environment (P<0.05). The calculated body heat content was higher in sheep at hot environment than at warm environment (P<0.05). Respiratory rate and plasma cortisol concentration had no significant differences between warm and hot environment, suggesting that sheep were not stress by the hot environment in this experiment. It is, therefore, suggested that sheep were well adopted to hot environment by increasing body heat content against heat stress.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.6
• /
• pp.859-865
• /
• 2002

The aim of this research was to clarify the direct effects of a hot environment on ruminal motility in sheep fed twice a day. In the first experiment, in order to equalize variable factors excluding the ambient temperature between the thermoneutral environment ($23^{\circ}C$, relative humidity 80%) and the hot environment ($32^{\circ}C$, relative humidity 80%), sheep were fed equal amounts of the same quality feed twice a day. The sheep were allowed free access to water for the duration of the two one-hour feeding periods (10:00 am-11:00 am, 5:00 pm-6:00 pm). On the fourth day after exposure to the hot environment, the frequency and strength of ruminal contractions were continuously recorded between 9:30 am and 11:00 pm. Prior to the exposure to a hot environment the frequency and strength of ruminal contractions were recorded in a thermoneutral environment during the period 9:30 am-11:00 pm. In the second experiment, in order to maintain the stomach content of the sheep at equal levels in both environments, the sheep were fed equal amounts of the same quality feed twice a day. Following the completion of the two one-hour feeding periods, a fixed amount of warm water was infused into the rumen. Rumen motility was then recorded during the same period as for the first experiment (9:30 am-11:00 pm). In the first experiment, when the frequency of ruminal contractions prior to (24, 24 frequency/15 min), during (48, 47 frequency/min) and after (22, 19 frequency/min) both the morning and afternoon feeding in a hot environment was compared with the values from the thermoneutral environment (20, 22; 50, 50; 21, 20 frequency/min), there was found to be no difference. However, the strength of ruminal contractions after morning and afternoon feeding (3.7, 3.1 mm Hg) in the hot environment decreased significantly in comparison with the thermoneutral environment (4.3, 3.8 mm Hg). In the second experiment, the frequency of ruminal contractions in the hot environment was not significantly different from that in the thermoneutral environment. The strength of ruminal contractions after ruminal infusion of warm water in the hot environment (morning: 4.6, afternoon: 4.5 mm Hg) was significantly lower than that in the thermoneutral environment (morning: 5.6, afternoon: 5.0 mm Hg). The results suggest that a hot environment acts directly on the strength of ruminal contractions in sheep fed twice a day rather than on the frequency.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.25 no.1
• /
• pp.83-90
• /
• 2001

Cooling garments are being considered for reducing heat strain in hot environment. We evaluated the effectiveness of ice gel-based cooling vest in hot environment both resting and exercising. Four male subjects were exposed to heat(4$0^{\circ}C$, 50%RH) with vest or without it. The results were as follows; In case of the trial wearing ice gel-based cooling vest, total body weight loss, and local sweat volume were less than those without it. Mean skin temperature, rectal temperature, pulse, energy expenditure, temperature of inside clothes, and humidity of inside also were lower than those without cooling vest. By subjective thermal sensation, subjective humidity sensation, and thermal comfort sensation, it was proved that non-wearing vest decreased comfort than wearing that. These results suggested that wearing ice gel-based cooling vest reduced human heat strain in hot environment both resting and exercising.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.10a
• /
• pp.281-286
• /
• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment of curing temperature $35^{\circ}C$, . Flesh concrete tested slump. air contest and Hardening concrete valuated setting period of form, day of age 1, 3, 5. 7, 10, 28 compression strength in sealing curing. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Experiment result age 28day compression strength more higher plan concrete then standard environment in curing temperature $20^{\circ}C$, , most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$, replacement binder 25%, fine aggregate 15%. (2) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• Asian-Australasian Journal of Animal Sciences
• /
• v.2 no.3
• /
• pp.259-260
• /
• 1989

• Proceedings of the Korean Society for Bio-Environment Control Conference
• /
• 2000.11a
• /
• pp.13-17
• /
• 2000

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1506-1510
• /
• 2004

A mobile robot system is developed to inspect the condition of industrial facilities under hot environment. The mobile robot is equipped with internal and external heat insulating material, an internal cooling mechanism, two CCD cameras, wireless communication devices for both the control and image signals, and an embedded controller. The portable controller is equipped with two joysticks for both the mobile robot and the inspection CCD camera, an LCD monitor, and several buttons. The developed mobile robot travels on the internal floor in hot furnaces by operators' joystick operation, captures the images of facilities in the furnaces using a zoom CCD camera, and sends the images to the portable controller through wireless communication. The mobile robot can be operated without any problem under hot environment less than 400$^{\circ}C$ in 30 minutes. This kind of automatic inspection mobile robot can be helpful to prevent significant troubles of industrial facilities without danger of human beings under harmful environment.

• Asian-Australasian Journal of Animal Sciences
• /
• v.28 no.7
• /
• pp.966-975
• /
• 2015

Heat production in ruminants follows a diurnal pattern over the course of a day peaking 3 hours following afternoon feeding and then gradually declining to its lowest point prior to morning feeding. In order to clarify the cooling period most effective in reducing decreases in feed intake and milk production, experiments were carried out based on the diurnal rhythm of heat production and heat dissipation. In experiment 1, the effects of hot environment on milk production were investigated. The animals were kept first in a thermoneutral environment ($20.0^{\circ}C$, 80.0%) for 12 days, they were then transitioned to a hot environment ($32^{\circ}C$, 80.0%) for 13 days before being returned to second thermoneutral environment for a further 12 days. In experiment 2, the effectiveness of daytime cooling or nighttime cooling for improving milk production in hot environment was compared. While ten lactating Japanese Saanen goats (aged 2 years, weighing 41.0 kg) during early lactation were used in experiment 1, ten lactating goats (aged 2 years, weighing 47.5 kg) during mid-lactation were used in experiment 2. The animals were fed 300 g of concentrated feed and excessive amounts of crushed alfalfa hay cubes twice daily. Water was given ad libitum. The animals were milked twice daily. When exposed to a hot environment, milk yield and composition decreased significantly (p<0.05). Milk yield in the hot environment did not change with daytime cooling, but tended to increase with nighttime cooling. Compared to the daytime cooling, milk components percentages in the nighttime cooling were not significantly different but the milk components yields in the nighttime cooling were significantly higher (p<0.05). The results indicate that nighttime cooling is more effective than daytime cooling in the reduction of milk production declines in lactating goats exposed to a hot environment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.115-118
• /
• 2004

The purpose of this research is to investigate the noble gas isotope and the hydrochemical characteristics of hot springs in the Chungcheong area in Korea. This study was carried. out by the financial support of Korea-Japan joint research program of KOSEF, Noble gases are very useful tracers to investigate volatile elements circulation, because of their unique isotopic compositions in various reservoirs of the Earth. Isotopic ratios of noble gases has been carried out for If hot-spring samples from Daejon and its near areas in Korea last January 2004. Helium isotope ratio gave the evidence that helium gas of different origins(air-crust mixing origin, crust-origin and mantle-origin) is supplied into hot-spring waters in Korea. We found the distinct relationship between temperature of hot springs and helium gas origin.

• Journal of the Korean institute of surface engineering
• /
• v.49 no.1
• /
• pp.26-31
• /
• 2016

In this paper, the characteristics of a cavitation-erosion damage behavior on the STS 304 and hot-dip aluminized STS 304 under cavitation environment in sea water solution was investigated. The electrochemical experiments were carried out by potential measurement, anodic/cathodic polarization test, Tafel analysis, and also galvanostatic experiment in current density variables for the samples. The apparatus of cavitation-electrochemical experiment was manufactured in compliance with modified ASTM G-32 standard, with the conditions of sea water temperature of $25^{\circ}C$ and the measurement, amplitude of $30{\mu}m$. The damage behavior was analyzed by an observation of surface mophologies and a measurement of damage depth by a scanning electron microscope(SEM) and a 3D microscope, respectively, after electrochemical test. After polarization experiment under cavitation environment, much higher damage depths for the hot-dip aluminized STS 304 were observed comparing to the untreated STS 304. In addition, higher corrosion current density in hot-dip aluminized STS 304 presented than that of untreated STS 304 as a result of Tafel analysis.