• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.183-188
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• 2006

Heat transfer coefficients have great influence on finite element analysis results in elevated temperature forging processes. Experimentally calculated contact heat transfer coefficient is not suitable for one-time finite element analysis because analyzed temperature will be appeared to be too low. To get contact heat transfer coefficient for one-time finite element analysis, tool temperature in operation was measured with thermocouple and repeated finite element analysis was performed with experimentally calculated contact and cooling heat transfer coefficient. Surface temperature of active tool was obtained comparing measurement and analysis results. Contact heat transfer coefficient for one-time finite element analysis was achieved analyzing surface temperature between repeated finite element analysis and one-time finite element analysis results.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.86.6-86
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• 2001

For discriminating between water and oil, a novel method is proposed in this paper. As a fundamental result, the temperature dependence of ultrasonic travel time of water and oil measured from 5$^{\circ}C$ to 40$^{\circ}C$ at a step of 5$^{\circ}C$ is found as that the ultrasonic travel time of oil increases with increasing temperature, whereas that of water decreases. The proposed method for discriminating between water and oil is based on the opposite temperature dependence of ultrasonic travel time of water and oil. Besides the advantages of non-invasion and on-line measurement, there are no requirements of measuring the temperature of liquid being detected and obtaining previously a large quantity of database, and furthermore, only two times of measurements are ...

• Journal of Korea Multimedia Society
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• v.24 no.1
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• pp.30-39
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• 2021

Research in the field of health lighting has continued to advance to reproduce the color temperature of natural light which periodically changes. However, most of this research could only reproduce a uniform circadian color temperature of natural light, therefore failing to realize the characteristics of the circadian cycle of color temperature difference by latitude and longitude. To reproduce the color temperature of natural light on which the characteristics of a region are reflected, the collection technology of real-time characteristics of natural light is needed. If the color temperatures which are not within a periodical pattern due to climate changes, etc., are measured, it will be difficult to judge the occurrence (presence) of the anomalies and to reproduce the circadian cycle of the color temperature of natural light. Therefore, this study proposes an algorithm for judging the anomalies in real time based on the sliding window to reproduce the color temperature of natural light. First, the natural light characteristics DB collected through the on-site measurement were analyzed, the differential values at a one-minute interval were calculated and examined, and then representative color temperature circadian patterns by solar terms were drawn. The anomalies were then detected by the application of the sliding window that calculated the deviation of the color temperature for the measured color temperature data set, which was collected through RGB sensors, while moving along the time sequence. In addition, the presence of anomalies was verified through the comparison study between the detection results and the representative circadian cycle of the color temperature by solar term. The judgment method for the anomalies from the measured color temperature of natural light was proposed for the first time, confirming that the proposed method was capable of detecting the anomalies with an average accuracy of 94.6%.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.1 no.1
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• pp.37-49
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• 1994

The purpose of this study was to measure the oral temperature, skin temperature, and subjective discomfort according to the application time of ice bag on thigh, head, and abdomen. This study was also intended to suggest nursing principles about ice bag application by exploring the recovery time of skin temperature after the removal of ice bag. The design of this study was $8{\times}3$ factorial design with one sample repeated measure. Here, the application time of ice bag(criteria, 5min, 10min, 20min, 30min, 40min, 50min, 60min) and the application site of ice bag(thigh, head, abdomen) were independent variables. The subjects were 10 university woman students, and data collection was made from July, 1 to August 30, 1992. Rubber ice bag halfly filled with ice was covered with towel and applied on thigh, head and abdomen in other three days. Before applying the ice bag, oral temperature and skin temperature were checked for criteria. After ice bag was applied, skin temperature, oral temperature and VAS score were checked at first 5 minutes elapsed, and every 10 minutes until 60 minutes. After that, ice bag was removed, and oral temperature and skin temperature were also measured every ten minutes until 60 minutes. In this study, skin temperature and core temperature were measured by thermistor probe, and subjective discomfort was measured by 200mm VAS (Visual Analogue Scale). Some of the findings were as follows : 1. There were significant differences in skin temperature among the three application sites of ice bag as time go by. It was most decreased to $15.87^{\circ}C$ in thigh, and $19.47^{\circ}C$ in abdomen at 50 minutes after the application of ice bag, whereas $26.1^{\circ}C$ at 40 minutes in head. Before the application of ice bag, skin temperature showed significant differences in three sites, so that they were compared after the criteria was covariated. In other words, there was significantly more decrease of skin temperature in thigh and abdomen than head, after ice bag was applied for 20 minutes and more. 2. There was no significant difference in core temperature among the three application sites of ice bag during the time of application 3. There was no significant difference in subjective discomfort (VAS) among the three application sites of ice bag. 4. After the removal of ice bag, the recovery of skin temperature was significantly different in three sites during first 30 minutes. In head, skin temperature came up to criteria at 30 minutes after the removal of ice bag, but it was not recovered In thigh and abdomen even 60 minutes elapsed. 5. After the removal of ice bag, there was no significant difference in oral temperature among the three application sites of ice bag. 6. There was significant correlation between the skin temperature and VAS score only in thigh. In conclusion, it is suggested that head in more suitable site for the application of ice bag if it is used for the relief of fever or pain. When we apply ice bag on thigh or abdomen for the relief of pain, careful attention is required.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.2
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• pp.154-161
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• 1998

The effects of melting temperature and holding time on the critical current density($J_c$) of $YBa_2Cu_3O_x$ based superconducting bulk fabricated by MPMG process were investigated. The amount of the formed $Y_2BaCuO_5$ phases increased with the melting temperature. However, the value of critical current density was highest at 1120 $^{\circ}C$. With this proper melting temperature, the effect of holding time on the critical characteristics was also investigated. In the case of Ag addition, the volume of the formed $Y_2BaCuO_5$ phase when the amount of Ag addition was 10 wt% and 20 wt% was observed to be highest at 20 minute and 40 minute respectively. But in the specimen without Ag, volume of $Y_2BaCuO_5$ phase increased as the holding time increased. The proper melting temperature and the holding time obtained were 1120 $^{\circ}C$ and 20 minute. The long holding time was not effective for the $J_c$ improvement as well as the formation of $Y_2BaCuO_5$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.91-94
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• 2018

We develop a time-temperature indicator (TTI) that can determine whether thawing of fish and other fishery products has occurred during frozen storage. A polypropylene tube with an internal diameter of 3 mm was prepared and cut to a length of 14 to 20 mm. One end of the tube was thermally sealed and 0.1% acetic acid was injected into the other end; the tube was then frozen at $20^{\circ}C$. Then the open side of the frozen tube was blocked by sinking the tube into a 10% gelatin solution. The tube was attached to a polyvinyl packaging bag along blue litmus paper and the bag was put into a freezer at $-20^{\circ}C$. After freezing, the bag was removed to an ambient temperature of $20^{\circ}C$, and the time dependence of the color change of the litmus paper was observed. The color changed from blue to red, with the length of the red region increasing with time. Our TTI can be used as a part of a visible detection system and the detection program can conduct the elapsed time analysis on the length of the red region of the litmus paper indicating the degree of thawing. Thus, the TTI is a useful tool in the temperature management of frozen fish and fishery products.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.711-718
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• 2013

This study examined the effect of 3 evaluation factors(extraction temperature, extraction time and drinking temperature) on the 5 tastes (sour, sweet, malty, salty and bitter) of coffee. the aim of this experiment were threefold: i) to investigate the change of the 5 tastes depending on the each 3 evaluation factor ii) to examine the change of the 5 tastes depending on the extraction time, drinking temperature under fixing the group of extraction temperature iii) to research the preference for the taste of coffee depending on 3 evaluation factors. As a result, in relation to the evaluation factors, significance difference was made at the sour taste. And when extraction temperature was higher and extraction time was longer, the sour taste was felt stronger. To the contrary, when drinking temperature was lower, sour was stronger. When the extraction Temperature group was controlled, the sour and malty taste were stronger. The sour taste was stronger when drinking temperature was lower and delicate flavor was stronger when drinking temperature was higher. High preference was demonstrated at extraction temperature($98^{\circ}C$), extraction time(0 minute), drinking temperature($60^{\circ}C$) and higher malty taste.

• Journal of Korean Academy of Nursing
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• v.4 no.2
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• pp.93-106
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• 1974

The purposes of this study are to identify the necessity of utilization of electric thermometer, to determine the difference of clinical thermometers to reach maximum or optimum temperature, and to determine the length of time necessary for temperature taking, with Fahrenheit thermometer, electric thermometer, Yu Ⅱ centigrade thermometer, and Kuk ll centigrade thermometer. The first and second comparative Experiments were' conducted from August 25 through September 30, 1973. In the first experiment, Fahrenheit thermometer, which had been accurately teated two times, and electric thermometer have been utilized. These two kinds of thermometers were inserted simultaneously under the central area of the tongue and the mouth kept closed while thermometers were in place. All temperature readings were done at one minute interval until leaching-maximum temperature. These procedures were repeated one hundred times and the data were-analyzed statistically by means of the t-test. In the second experiment, Fahrenheit thermometer, which had been accurately tested two. times, Yu Ⅱ centigrade thermometer, and Kuk Ⅱ centigrade thermometer have been utilized. These three kinds of thermometers were inserted simultaneously under the central area of the. tongue and the mouth kept closed while thermometer were in place. All temperature readings were done at one minute interval until reaching maximum temperature. These procedures were. repeated one hundred times and the data were analyzed statistically by means of the F-ratio Under the eight hypotheses designed for this study, the findings obtained are as follows: 1. There were no significant differences in the maximum temperature between Fahrenheit thermometer and electric thermometer. The mean maximum temperature for Fahrenheit thermometers was 37.06℃ and for electric thermometer was 37.09℃. 2. The placement time to reach maximum temperature taken by Fahrenheit thermometer was significantly shorter than that by electric thermometer. The mean placement time for Fahrenheit thermometers was 4.04 minutes, for electric thermometer was 5.52 minutes. In the case of Fahrenheit thermometers, 45 to 77 percent after 3 to 5 minutes, over 90 Percent after 7 minutes, and 100 percent after 10 minutes, had reached optimum temperature. When the electric thermometer was used, 23 to 54 percent after 3 to 5 minutes, over 90 percent after 9 minutes, and 100 percent after 12 minutes, had reached optimum temperature. 5. There ware no significant differences in the maximum temperature among Fahrenheit thermometer, Yu Ⅱ centigrade thermometer, and Kuk Ⅱ centigrade thermometer. The mean maximum temperature for Fahrenheit thermometers was 36.67℃, for Yu Ⅱ centigrade thermometer, was 33.73℃, and for Kuk Ⅱ centigrade thermometers was 37.76℃. 6. There were no significant differences in placement time to reach maximum temperature among Fahrenheit thermometer, Yu Ⅱ centigrade Thermometer, and Kuk Ⅱ centigrade thermometer. The mean placement time (or Fahrenheit thermometers was 7.77 minutes, for Yu Ⅱ centigrade thermometers was 7.25 minutes, and Kuk Ⅱ centigrade thermometers was 7.25 minutes. In the case of Fahrenheit thermometers, 8 to 24 percent after 3 to 5 minutes, over 90 percent after 11 minutes, and 100 percent after 13 minutes, had reached maximum temperature. When the Yu Ⅱ centigrade thermometer was used, 10 to 27 percent after 3 to 5 minutes, over 90 percent after 11 minutes, an8 103 percent after 13 minutes, had reached maximum temperature. When the Kuk Ⅱ centigrade thermometer was used, 11 to 27 Percent after 3 to 5 minutes, over 90 percent after 11 minutes, and 100 percent after 12 minutes, had reached maximum temperature. 7. There were no significant differences in the optimum temperature(the maximum temperature minus 0.1℃) among fahrenheit thermometer, Yu Ⅱcentigrade thermometer, and Kuk Ⅱ centigrade thermometer. The mean optimum temperature for Fahrenheit thermometers was 36.60℃, for Yu Ⅱ centigrade thermometers was 36.69℃, and Kuk Ⅱ centigrade thermometers was 36.69℃. 8. There were no significant differences in placement time to reach optimum temperature among Fahrenheit thermometer, Yu Ⅱ centigrade thermometer, and Kuk Ⅱ centigrade thermometer The mean placement time for Fahrenheit thermometers was 5.70 minutes, for Yu Ⅱ centigrade thermometers was 5.54 minutes, and for Kuk Ⅱ centigrade thermometers was 5.28 minutes. In the case of Fahrenheit thermometers, 21 to 49 percent after 3 to 5 minutes, over 90 percent after 9 minutes, and 100 percent after 12 minutes, had reached optimum temperature. When the Yu Ⅱ centigrade thermometer was used, 23 to 51 percent after 3 to 5 minutes over 90 percent after 10 minutes, and 100 percent after 12 minutes, had reached optimum temperature. When the Kuk Ⅱ centigrade Thermometer was used, 23 to 57 Percent after 3 to 5 minutes, over 90 percent after 9 minutes, and 100 Precent after 11 minutes, had reached optimum temperature.

• Corrosion Science and Technology
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• v.4 no.4
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• pp.147-154
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• 2005

The creep resistance of geogrids is one of the most significant long-term safety characteristics used as the reinforcement in slopes and embankments. The failure of geogrids is defined as creep strain greater than 10%. In this study, the accelerated creep tests were applied to polyester geogrids at various loading levels of 30, 50% of the yield strengths and temperatures using newly designed test equipment. Also, the new test equipment permitted the creep testing at or above glass transition temperature($T_g$) of 75, 80, $85^{\circ}C$. The time-dependent creep behaviors were observed at various temperatures and loading levels. And then the creep curves were shifted and superposed in the time axis by applying time-temperature supposition principles. The shifting factors(AFs) were obtained using WLF equation. In predicting the lifetimes of geogrids, the underlying distribution for failure times were determined based on identification of the failure mechanism. The results confirmed that the failure distribution of geogrids followed Weibull distribution with increasing failure rate and the lifetimes of geogrids were close to 100 years which was required service life in the field with 1.75 of reduction factor of safety. Using the newly designed equipment, the creep test of geogrids was found to be highly accelerated. Furthermore, the time-temperature superposition with the newly designed test equipment was shown to be effective in predicting the lifetimes of geogrids with shorter test times and can be applied to the other geosynthetics.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.325-331
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• 2011

A new method to predict the proper promotion time on the near-step-temperature test profile when heating or cooling the test-piece in a test chamber to the test temperature for environmental tests has been proposed by using the lumped analysis. For a given test condition the analysis shows the existence of a promotion time that reduces the testing time and saves energy. The theoretical results are in reasonably good agreements with experimental results for steel specimens. The suggested promotion time is approximately proportional to the mass/surface area of the test-piece for a given material.