• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1478-1486
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• 2018

Liquid crystals offer plenty of useful activities as improving the stability of emulsion, increasing moisturizing power, drug release, improving skin feeling and visual effect for cosmetics fields. In order to prepare stable semi-transparent gel emulsion, liquid crystal emulsification method was used. The emulsion stabilities of systems containing glycerin, fatty alcohols, surfactants, water and oil were investigated at various temperatures as time passed. The stabilities of all emulsions were evaluated by means of a polarizing microscope, SEM, rheometer, colorimeter and DSC. Even though the samples stored at $50^{\circ}C$ thermostatic chamber were occurred the reduction of hardness, turbidity and ${\Delta}H$ and the peak shift, the semi-transparent gel emulsion was very stable without separation between water and oils phase in emulsion.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.4
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• pp.433-439
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• 2015

Enclosures for CCTV internal short circuit are prevented due to wetting to maintain a constant humidity and temperature, to avoid condensation due to temperature difference, a constant temperature and humidity requirements of the equipment, such as high-temperature resistant and a constant temperature of the structure, degree of energy utilization is optimized for developing this corresponding housing automatic control system and humidity is required. Device being an expensive imaging equipment in side of the enclosure according to the temperature conversion from a hazard protection, there is a need for a constant temperature and humidity control apparatus that can prevent a short-circuit failure. This is a system in which the accessory device is absolutely required for the storage and transmission of an image in recording reliability and field conditions.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3804-3814
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• 2000

This paper presents an efficient implementation of a run-time monitor which checks the satisfaction of the timing constraints of real-time object-oriented programs based on a real-time object model called TMO(Time-triggered Messagedtriggered Object). An execution environment of TMO programs on Windows as, WTMOS(Windows TMO System) has been utilized for the implementation and an experimental application for thermostatic control has been developed to analyze the performance of the run-time monitor. We suggest a methodology for application programmers to specify the target methods with the monitoring conditions and an implementation technique which incurs the small cost by effectively distributing the functions of the monitor into the WTMOS and a TMO object.

• The korean journal of orthodontics
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• v.11 no.2
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• pp.151-160
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• 1981

The purpose of this study was to compare the retentive values of various dental cements used for cementing the orthodontic bands on the teeth. Sound freshly extracted human premolar teeth were selected for the study. Eleven commercial dental cements (Zinc phosphate, reinforced Zinc-oxide eugenol, Carboxylate and Glass ionomer cements) were handled under standardized conditions. All cemented speciments were then kept in a thermostatic humidor cabinet regulated at $23{\pm}2^{\circ}C$ and more than $95\%$ relative humidity and tested after 24 hours and 1 week each. The force required to remove the cemented orthodontic bands from the teeth was determined on an Instron Universal Testing Machine using a modified specimen holding device with a cross-head speed of 0.20mm/min. The results obtained were as follows: 1, The retentive values of the band cemented with zinc phosphate cements and carboxylate cements were considerably higher than those of the reinforced zinc oxide-eugenol and glass ionomer cements. 2. There was no significant difference between the retentive value of carboxylate cements as compared with zinc phosphate cements. 3. The retentive value of the reinforced zinc oxide eugenol cements was lowest all of the coements. The retentive values expressed for all cements up to at least one week were highly but no significant difference was found between the 24-hour and 7 day time intervals.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.493-496
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• 2000

This study is about the design and fabrication of optical voltage sensor modules improved in the insulation reliability, where we adopted the space-division voltage system using the auxiliary electrodes to apply the uniform electric fields to the BSO, the device of which the polarization state varies with the variation of refractive index in the electric fields. We measured the output of fiber-Optic Voltage Sensors with the temperature changes in the thermostatic oven. And we measured the output of Fiber-Optic Voltage Sensors after setting its up in the disttibuion automated switch being apply 60Hz alternating voltage from 6.6kV to 17.BkV. In result, measured error characteristic is good, so we can judge it is applicable to the practical case

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.4
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• pp.380-387
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• 1994

An experimental study was performed to investigate the characteristics of refrigerant flow rate control and superheat in an evaporator with an electronic expansion valve(EEV). The EEV used in this study was devised using a needle valve coupled with a stepping motor controlled by a personal computer. A Pill control equation was used to control the superheat of the evaporator and to set the superheat to $5^{\circ}C$. In order to determine an optimum running condition for the system, Pill parameters were varied for the wide range of values. The running condition of an air conditioning system with a PI control was reasonably stable compared with that of the Pill control. Experimental results for the PI control using parameter values, $K_p=1.5$, $T_i=400(sec)$ and $T_s=6(sec)$ show that the superheat reached its target value. When external disturbances were introduced to the system, the superheat target value was reached within about 3 minutes. When the EEV was applied to the air conditioning system driven by an inverter, room temperature control was excellent.

• Journal of Biosystems Engineering
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• v.12 no.1
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• pp.6-13
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• 1987

A mathematical model for the waste heat recovery system for an engine was developed. The model based on the experimental data reported before was validated and was used to predict the waste heat recovery and recoverable heat of the engine at various operating conditions of the engine and the system. The model was also used to determine flow rates of the circulating water in the system for a certain temperature increment of the water at various operating conditions of the engine to give basic data to design the system. Stability of the system performance was tested on subjects of vapor lock problem, thermal characteristics of the thermostatic valve, and temperature variation of the circulating water in the engine and fuel consumption of the engine during each mode of the system operation and its change into the other. The test showed that the system operation was stable enough. Temperature profile in the thermal energy storage (TES) was observed during storing thermal energy, and thermal stratification in the TES was well formed acceptable to be used in the system. Finally a scheme to automatize the system was suggested.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.246-251
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• 1997

The phase behavior of sucrose monopalmitate/alkanol/water ternary system was investigated. According to compositions of three components ranging from micellar(or inverse micellar) solution up to various lyotropic liquid crystalline(LC) phase, each texture of the separated phases was identified by crossed polarizers equipped with a camera whose stage was connected to a thermostatic circulator. As the carbon atom number in alkanol of the polar oily substance increases, patterns of the various LC phases were also observed hexanol

• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.2
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• pp.60-68
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• 2000

An experimental study was peformed to investigate characteristics of an inverter driven heat pump system with a variation of compressor frequency and expansion device. The compressor frequency varied from 30Hz to 75Hz, and the performance of the system ap-plying three different expansion devices such as capillary tube, thermostatic expansion valve(TXV), and electronic expansion valve (EEV) was measured. The load conditions were altered by varying the temperatures of the secondary fluid entering condenser and evaporator with a constant flow rate. When the test condition was deviated from the standard value(rated value), TXV and EEV showed better performance than capillary tube due to optimal control of mass flow rate and superheat. In the present study, it was observed that the variable area expansion device had better performance than constant area expansion device in the inverter heat pump system due to active control of flow area with a change of com-pressor frequency and load conditions.

• The Korean Journal of Food & Health Convergence
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• v.5 no.5
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• pp.11-25
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• 2019

Extraction of oil from Moringa oleifera seed using Response Surface Methodology (RSM) was investigated. Effects of three factors namely: sample mass, particle size and extraction time on the response, Moringa oleifera a volume extracted, were determined. The Box-Behnken design of RSM was employed which resulted in 15 experimental runs. Extraction was carried out in a 250 ml Soxhlet extractor with Hexane and Ethanol as solvent. The Moringa oleifera seed powder was packed inside a muslin cloth placed in a thimble of the Soxhlet extractor. The extraction was carried out at 60℃ using thermostatic heating mantle. The solvent in the extracted oil was evaporated and the resulting oil further dried to constant weight in the oven. This study demonstrates that Moringa oleifera oil can be extracted from its seed using ethanol and acetone as extraction solvent. The optimum process variables for both solvent (ethanol and acetone) was determined at sample weight of 40 g, particle size of 325 ㎛ and extraction time of 8 hours. It can be deduced that using acetone as solvent produces a higher yield of oil at the same optimum variable conditions compared to when ethanol was used.