• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.31-31
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• 2007

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1C
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• pp.29-38
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• 2011

The smaller diameter cone penetrometer has been widely used to estimate the characteristics of local area due to high vertical resolution. The half-bridge cirucits have been adopted to measure the mechnical strength of soil through the smaller diameter cone penetrometer due to the limitation of the areas for configuring the full-bridge circuit. The half-bridge circuit, however, is known as being easily affected to the temperature variation. The objective of this study suggests the temperature-compensated method in mini-cones. The diameter and length of the mini-cone is designed to 15mm and 56mm. The load cell of the mini-cone is extended about 54mm on the behind of the mini-cone to reflect the only temperature variation. The full-bridge circuit is installed to measure the temperature-compensated values in the mini-cone and the half-bridge circuit is also organized to compare the temperature compensated values with uncompensated values. The seasonal variation tests are performed to define the effect of temperature variation under summer and winter temperature condition. The densification tests are also carried out to investigate temperature effects during penetration. The measured mechanical resistances with temperature-compensated method show more reliable and reasonable values than those measured by thermal uncompensated system. This study suggests that the temperature-compensated method of the mini-cone may be a useful technique to obtain the more reliable resistances with minimizing the temperature effect.

• International Journal of Aeronautical and Space Sciences
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• v.4 no.2
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• pp.51-60
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• 2003

An experimental research program is being undertaken to develop a regeneratively-cooled experimental thrust chamber of liquid rocket engine using liquefied natural gas and liquid oxygen as propellants. Prior to firing test using a regenerative cooling with liquefied natural gas in this program, several firing tests were conducted with water as a coolant. Experimental thrust chambers with a thrust of about 10tf were developed and their firing test facility was built up. Injector used in the thrust chamber was of shear-coaxial type appropriate for propellants of gas and liquid phase and cooling channels are of milled rectangular configuration. Periodical variation of the soot deposition and discoloration was observed through an eyes' inspection on the inner wall of a combustion chamber and a nozzle after each firing test, and an intuitive concept of the periodical variation of mixture ratio near the inner wall of a combustion chamber and a nozzle at once was brought about and analyzed quantitatively. Thermal heat flux to the coolant was calculated and modified with the periodical variation model of mixture ratio, and the increment of coolant temperature at cooling channels was compared with measured one.

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.870-878
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• 2003

The scale is removed from the strip by high pressure hydraulic descaling at the FSB (Finishing Scale Breaker). Recently, the spray height of nozzle has a trend to be shorter for the purpose of increasing the impact pressure by the high pressure water jet. Here, the nozzle intervals should be decided after considering the impact pressure and the temperature distribution on the strip. In other words, the minimum of impact pressure at the overlap of spray influences the surface grade of the strip due to scale and the overlap distance of the spray affects the temperature variation in the direction of the width of strip. In the present study, the impact pressure of the high pressure water jet is measured by the hydraulic descaling system and calculated with regard to the lead angle of 15$^{\circ}$ and the offset angle of 15$^{\circ}$, and then the temperature distribution and the temperature variation are calculated at the overlap distances of 0 mm, 10 mm, 20 mm, and 30 mm, respectively. The method of setting nozzle intervals is shown by utilizing these results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.1
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• pp.27-33
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• 1999

Compact fluorescent lamps are very sensitive to the variation of ambient temperature. This paper investigates the temperature characteristics of a 15[W] compact fluorescent lamp, and compensates the variation of light output by frequency control of its electronic ballast. Circuit parameters for the inverter of the electronic ballast are obtained by analyzing the R-L-C equivalent circuit for the inverter and the lamp. The optimum ratio of the two capacitance($C_1$/$C_2$), which are connected with the lamp in series and in parallel, respectively, is determined which consideration of the temperature variation within a range of 10~35[$^{\circ}C$]. As a result a value of 10 for the ratio is obtained at an operating frequency of 57[kHz], and with this value the frequency control works well for temperature compensation. Its validity is verified by investigating light output stabilization characteristics resulting from frequency control of the lamp at various temperatures.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.1
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• pp.55-62
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• 2006

Correlations between air-temperature variation and SST variation around Jeju Island have been studied with data JRMO($1924{\sim}2004$) and NFRDI($l971{\sim}2000$). Air-temperature has increased about $0.02^{circ}C/year$ for the period of $1924{\sim}2004$ but relatively high 0.035/year for the last 30 years. SST has increased about $0.024^{circ}C/year$ for the period of $1971{\sim}2000$ and relatively high $0.047^{circ}C/year$ in December. According to the analysis of time series of the two kind of variation, the SST and air-temperature are positively correlated. They are generally in phase, and SST anomaly is similar to air-temperature anomaly as well. Consequently, SST variation has high correlation with air-temperature variation around Jeju Island.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.148-151
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• 2005

This paper is concerned with the thermo-mechanical behavior and temperature dependent strain rate sensitivity of steel sheet for an auto-body. In order to Identify the temperature dependent strain rate sensitivity of SPRC35R and SPRC45E, uniaxial tension tests are performed with the variation of the strain rates from 0.001/sec to 200/sec, and the variation of environmental temperatures from $-40^{\circ}C\;to\;200^{\circ}C$. The thermo-mechanical response at the quasi-static state is obtained with the static tensile test and at the intermediate strain rate is from the high speed tensile test. The experimental results show that the strain rate sensitivity increases at low temperature and it decreases at high temperature. It means that as the strain rate getting increasing, the variation of flow stress is more sensitive on the temperature. The results also indicates that the material properties of SPRC35R is more depend on the changes of strain rates and temperature than those of SPRC45E.

• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.88-96
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• 2000

The present study estimated the variation of early survival of chum salmon families with respect to temperature and size after transfer to seawater. Heritability for seawater tolerance of half-sib families was also estimated at 45 days after hatching. Gametes were collected from 6 male and 18 female chum salmon to make 18 paternal half-sib families. Seawater tests were carried out at 3, 7 and $12^{\circ}C$ of $32\%$ seawater and compared with freshwater. Survival was significantly affected by seawater temperature. The highest seawater tolerance was obtained in 45-day old chum salmon at $7^{\circ}C$ seawater and the lowest seawater tolerance was obtained at $3^{\circ}C$. Overall survivals in seawater tolerance at $32\%$ varied among families. There were significant variance in fry survival among females (P=0.0001), and among males (P=0.0001). The heritabilities of survival in seawater in chum salmon were estimated to be 0.32-0.34 for the sire components at 45 days after hatching in 1998.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.3
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• pp.4483-4491
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• 1977

The results obtained are as follows; 1. The variation of the temperature in a vinyl house without heating system is similar to that of air temperature in a day. The difference of maximum temperature and minimum one in a day is 27$^{\circ}C$ which is two times greater than the daily difference of air temperature. 2. When the length of the duct is increased, the high temperature zone is built up in the direction of warm air discharge from the duct, and the low temperature zone is built up in the opposite direction of warm air discharge. But, in case of the duct length is short (0.05 L), the temperature distrubution in a vinyl house become uniform. It is concluded that the shorter length of the duct, the better the distribution of the temperature in a vinyl house is. 3. When the duct is installed at high position, the high temperature zone is built up in the upper zone of the vinyl house and the low temperature zone is built up in the lower zone. And when the position of the duct is low, the rate of temperature variation along the vertical direction become high, and the direct contact of warm air with the plant in the house is occured. It is concluded that the duct should be installed at the position of slightly higher than the plant height. 4. When the fuel consumption rate is fixed at the 101/hr, the lowest temperature warming rate in the vinyl house is 5$^{\circ}C$ without regard to the air temperature.

• Journal of Industrial Technology
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• v.15
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• pp.187-193
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• 1995

In this paper, a short-term load forecasting expert system considering the load variation due to the change in temperature is presented. The change in temperature is an important load variation factor that varies the normal load pattern. The conventional load forecasting methods by artificial neural networks have used the technique where the temperature variables were included in the input neurons of artificial neural networks. However, simply adding the input units of temperature data may make the forecasting accuracy worse, since the accuracy of the load forecasting in this method depends on the accuracy of weather forecasting. In this paper, the fuzzy expert system that modifies the forecasted load using fuzzy rules representing the relations of load and temperature is presented and compared with a conventional load forecasting technique. In the test case of 1991, the proposed model provided a more accurate forecast than the conventional technique.