• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.47-48
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• 2018

The aim of the research is to suggest the compensating strength values depending on various managing periods of concrete based on the strength development model calculated with equivalent age method for OPC 100 % concrete. As a result, for 28 days of managing period, 6, and 3 MPa of compensating strength values were suggested when the temperatures were from 4 to 9℃, from 9 to 17℃, respectively. Additionally, for 42 days of managing period, 3MPa of compensating strength value was suggested when the temperature was from 4 to 10℃, and for 56 days of managing period, 3 MPa of compensating strength value was suggested when the temperature was from 4 to 5℃. Furthermore, for 28, 42, 56, and 91 days of managing periods, any compensating strength values were needed when the temperature were higher than 17, 10, 5, and 4℃, respectively.

• The KSFM Journal of Fluid Machinery
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• v.15 no.6
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• pp.18-24
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• 2012

This study simulated the operation of a steam injected gas turbine combined heat and power (CHP) system. A full off-design analysis was carried out to examine the change in the turbine blade temperature caused by steam injection. The prediction of turbine blade temperature was performed for the operating modes suggested in the previous study where the limitation of compressor surge margin reduction was analyzed in the steam injected gas turbine. It was found that both the fully injected and partially injected operations suggested in the previous study would cause the blade temperature to exceed that of the pure CHP operation and the under-firing operation would provide too low blade temperature. An optimal operation was proposed where both the turbine inlet temperature and the injection amount were modulated to keep both the reference turbine blade temperature and the minimum compressor surge margin. The modulation was intended to maintain a stable compressor operation and turbine life. It was shown that the optimal operation would provide a larger power output than the under-firing operation and a higher efficiency than the original partially injected operation.

• Tunnel and Underground Space
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• v.6 no.1
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• pp.69-74
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• 1996

High temperature confined compressive tests for thermomechanical failure criteria were carried out for Iksan and Whandeung granites. Authors suggested new polynomial type failure coefficient functions by which conventional Hoek-Brown failure criteria was extended to thermomechanical one. Obtained results are as follow; 1) Failure coefficients, m and s of Hoek and Brown's empirical failure criteria were decreased as temperature increased. 2) Theoretically calculated values by suggested equations and experimented ones by confined compressive test were well coincided.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2099-2104
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• 2015

The paper presents a monitoring system for the cooling of distribution transformers. The suggested system is controlled by a microcontroller scheme. The system is designed to control the oil temperature. It gives a solution to improve the cooling system by adding a number of fans especially for indoor transformers that are placed in badly-ventilated rooms. Also, the paper includes an alarm system with the possibility of tripping the transformer if it is necessary. The monitoring system consists of acquisition temperature sensor, and on-site unit. The hardware and software of the on-site unit are demonstrated with sufficient illustrations. Small prototype is constructed in the laboratory. Some laboratory experiments are carried out for examining the designed circuit by using Proteus Virtual System Modeling as well as for testing the prototype monitoring system. Concerning this research point, a study is carried out to evaluate the economic feasibility. The results are recorded and associated with many recommendations that may be valuable to electrical distribution (utility) companies.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.107-112
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• 2014

To cope with the ever increasing electric power demands in metropolitan areas, a greater underground cable transmission capacity is required. In general, it must be determined whether the temperature in the tunnel maintains the maximum allowable temperature. In order to improve this point, it is used to the loss factor. But, for economic cooling, it is problem to use such loss factor in this country. In this study, based on the load factor in this country, technique for calculating the loss factor has been presents. The suggested method has been tested in a sample section using the computer and the results have shown the usefullness of the suggested method.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.4
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• pp.8-14
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• 2016

In this study, the effects of prediction and reset control of outdoor air temperature on energy consumption for central heating system are researched by using TRNSYS program package, and the control performances with the suggested methods of prediction and reset control of outdoor air temperature are compared with the existing ones. As a result, the value of coefficient of determination $R^2$ for the predicted outdoor temperatures is improved and the suggested control method shows maximum 21.8% energy saving in comparison with existing control ones.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.223-228
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• 2009

Cooling and heating equipments of railroad passenger cabin is one of the most important part in keeping the good thermal comfort of the passengers. The bad performance of these equipments usually results in the comfort of the passengers. However, there is no testing method for cooling and heating equipments during manufacturing the passenger car, and calculation method is frequently used. Many railroad operators spend a lot of money for the maintenance. In this study, a new environmental performance test for railroad passenger cabin was suggested. The temperature of the chamber will be changed from $-40^{\circ}C$ to $60^{\circ}C$. The performance test of cooling and heating equipment in controlling the passenger cabin temperature was carried out under various temperature condition. The testing method to investigate the effect of artificial sunlight irradiation on the passenger cabin temperature was also suggested.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.63-69
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• 2012

As decreasing size of chips, the need of wafer level packaging is increased in semi-conductor and display industries. Temperature uniformity is a crucial factor in vacuum soldering process to guarantee quality of bonding between chips and wafer. In this paper, a stepwise iterative algorithm has been suggested to obtain output profile of each heat source. Since this algorithm is based on open-loop stepwise iterative experimental technique, it is easier to implement and cost effective than real time feedback controls. Along with some experiments, it was shown that the suggested algorithm can remarkably improve temperature uniformity of wafer during whole heating process compared with the ordinary manual trial-and error method.

• International Journal of Air-Conditioning and Refrigeration
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• v.11 no.4
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• pp.170-177
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• 2003

The electric power load during the summer peak time is strongly affected by cooling load, which decreases the preparation ratio of electricity and brings about the failure in the supply of electricity in the electric power system. The ice storage system and heat pump system etc. are used to settle this problem. In this study, the method of estimating temperature and humidity to forecast the cooling load of ice storage system is suggested. The method of forecasting the cooling load using neural network is also suggested. The daily cooling load is mainly dependent on actual temperature and humidity of the day. The simulation is started with forecasting the temperature and humidity of the following day from the past data. The cooling load is then simulated by using the forecasted temperature and humidity data obtained from the simulation. It was observed that the forecasted data were closely approached to the actual data.

• Journal of the Korean Ceramic Society
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• v.37 no.4
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• pp.332-337
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• 2000

Forming mechanism of fibrous TiC during self-propagating high temperature synthetic reaction was analyzed and suggested. It was revealed that critical temperature for the stable fiber formation was not the melting point of TiC, but the eutectic reaction temperature of TiC and C. Minimum amount of TiC diluent addition required to form fibers was calculated to be 25.6%, which was consistent with the experimental result. Synthesized fibers were found hollow tube-like. The morphology was explained by the diffusion rates of C and Ti in TiC, and by the molar volume chnage of C during the reaction. Expanding shell model was suggested for the hollow fiber formation mechanism.