• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.2
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• pp.202-216
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• 1998

A computer simulation for the performance analysis of automobile air conditioning components is carried out for the various operating conditions. The automobile air conditioning system consists of laminated type evaporator, swash plate type compressor, parallel flow type condenser, externally equalized thermostatic expansion valve and receiver drier. The overall heat transfer coefficient and the pressure drop in laminated type evaporator were obtained through experiments. In parallel flow type condenser, the performance analysis computer program using the empirical equation for heat transfer coefficient has been developed and the results are compared with experimental results. A model for matching the performance analysis programs of respective components .of automobile air conditioning system is introduced. Further, the effects of varying condenser size and refrigerant charge on the performance of automobile air conditioning system are discussed clearly.

• Journal of Digital Convergence
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• v.18 no.3
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• pp.275-285
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• 2020

The aims of this study was to examine the effect on the hand disinfection performance, the performance rate, and the satisfaction with the use of the belt-type hand sanitizers in clinical nurses. The study is a one group pre-post test quasi-experimental design. Effectiveness of using the belt-type hand sanitizers was measured with a self-reporting questionnaire. As a result, the performance of hand disinfection and the performance rate were significantly higher after using the belt-type hand sanitizers, and also, the satisfaction with the use of the belt-type hand sanitizers was significantly high. The belt-type hand sanitizer is effective method to improve both hand disinfection performance and its performance rate. Therefore, if the belt-type hand sanitizer is used in clinical practice, it may contribute to the improving the hand disinfection performance and its performance rate.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.225-238
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• 2022

The purpose of this study is to explore the performance characteristics and laws of the symbol mark design of representative regional history museums in China, as well as the preferences of Chinese audiences for the symbol marks of different types of Chinese regional history museums. First, the performance theme, performance type, and type performance tendency of symbol mark modeling of the regional history museums among the top 100 museums in China are analyzed. Second, design laws based on the interrelationship of performance theme types and design performance types are explored. Finally, the questionnaire survey is carried out to explore preference from the aspects of attention, readability, closeness, originality, aesthetics and comprehensiveness. According to the results, the theme of regional history is the most in terms of themes. As for the modeling performance types, the concrete type and the visualization of Chinese character are the most. According to the content characteristics of different performance types, the following model characteristics are formed: expressing the theme of regional history, architecture, and regional natural ecological environment through the concrete type, expressing the concept through the abstract type, and expressing the concept and implying some building features through the geometric abstract figure. The three forms of the literal type, the concrete type expressing architecture, regional history, and regional natural ecological environment theme content, and the abstract type expressing concept are combined with each other, and expressed through the visualization of character, the mixture of abstract and literal type, the mixture of concrete and abstract type, and the mixture of concrete and abstract literal type in the mixture type. According to the survey results, Chinese audiences have higher preference for the concrete type in the symbol mark performance type and the regional historical theme in the performance content.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.75-81
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• 2000

To provide the appropriate direction for development of transient control in a gasoline engine, transient performance analysis and evalution under four accelerating types based on typical driver's acceleration type were implemented by experimental study. In order to evaluate the characteristics of transient performance quanititatively, the concept and method by transient response specifications were introduced. Several performance parameters in terms of engine speed(RPM), manifold absolute pressure(MAP), fuel injection duration($\DeltatI_{nj}$) and air excess ratio($\lambda$) were emasured simultaneously during the four types of the throttle valve opening with the step motor controlled by PC. The result showed that transient response specifications in terms of delay time, rising time and settling time characterized the transient performance for four acceleration types quantitatively. Intensified acceleration type was most economical and linear acceleration type revealed the best emission performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.160-170
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• 1997

The objective of this study is to investigate the atomization characteristics and the performance characteristics of a C. I. engine by using the changes of the injection nozzle type and the ultrasonic-energy-added system. In order to evaluate the effect of ultrasonic energy and of change of injection nozzle type in the performance characte- ristics of a diesel engine, measurements of droplet size of diesel fuel were carried out by using Malvern system. In all types of injection nozzles, SMD of the ultrasonic- energy -added diesel fuel was smaller than that of the conventional diesel fuel and the more injection pressure increased, the more SMD decreased. There was a small increase in SMD with the distance from injection nozzle under all conditions of the injection nozzle types. The minimum SMD was found in the injection nozzle of B type. In the diesel engine test, there were three results about the engine performance. Compared with the injection nozzle of A type, B type had excellent effects in the engine performance. The most excellent effects about the engine performance were obtained in the case of ultrasonic-energy-added diesel fuel. In addition, the torque diagram in the case of ultrasonic-energy-added diesel fuel was more stable and periodical than others.

• Journal of Biosystems Engineering
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• v.37 no.3
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• pp.140-147
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• 2012

Purpose: This study was conducted to understand the work performance of crank-type rotavators and compare them with those of rotary-type rotavators in Korean farmland conditions. Methods: Tillage operations were carried out using both rotavators with the same nominal rotavating width and rated power. During the operations, PTO speed and torque, actual work speed, and rotavating width and depth were measured. To evaluate work performance, pulverizing ratio, inversion ratio, and specific volumetric tilled soil were calculated and compared for each rotavator. Results: It is found that the crank-type rotavator has better specific volumetric tilled soil performance and deep tillage, while the pulverizing ratio is worse. Conclusions: Crank-type and rotary type rotavator have diffenent properties each other in several work performances. It's important, therefore, to choose a suitable type of rotavator that satisfy the farmer's requirements in accordance with the condition of field and the purpose of tillage operation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.9
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• pp.424-433
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• 2014

The purpose of this study is to evaluate the effectiveness in the lighting performance of mixed type light-shelf, by comparing and analyzing the internal light-shelf, external light-shelf, and mixed-type light-shelf. The performance of light-shelf was evaluated according to the angle of light-shelf at summer solstice, winter solstice, vernal equinox, and autumn equinox. The comparative analysis between the internal light-shelf, external light-shelf, and mixed-type light-shelf was carried out using the performance evaluation and analysis method. The result of performance evaluation is shown as follows. The mixed type light-shelf showed the highest lighting performance all at summer solstice, winter solstice, vernal equinox, and autumn equinox, followed by the external light-shelf and the internal light-shelf in the same order. The mixed type light-shelf was the most favorable for bringing daylight to indoors by adjusting the angle of light-shelf, and it also showed the highest lighting performance in terms of uniformity ratio of illumination which indicates the quality of light.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.1
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• pp.53-59
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• 2009

The objectives of this paper are to study the characteristics of heat transfer and pressure drop of the micro channel heat exchangers using diffusion bonding technology. Four types of heat exchangers are designed and manufactured, which are straight type, long dot type, splited wavy type and straight double side type. Heat transfer and pressure drop performance of each heat exchangers are measured in various operating conditions, and compared each other. The results show that the $(j/f)^{1/3}$ performance of splited wavy type and long dot type increases about 10.3% and 6.1% at the Reynolds number 470 compared to that of straight type, respectively. On the other hand, $(j/f)^{1/3}$ performance of straight double side type decreases 19.7%.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2304-2309
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• 2008

The objectives of this paper are to study the characteristics of heat transfer and pressure drop of the micro channel heat exchangers using diffusion bonding technology. Four types of heat exchangers are designed and manufactured, which are straight type, long dot type, splited wavy type and straight double side type. Heat transfer and pressure drop performance of each heat exchangers are measured in various operating conditions, and compared each other. The results show that the $(j/f)^{1/3}$ performance of splited wavy type and long dot type increases about 10.3% and 6.1% at the Reynolds number 470 compared to that of straight type, respectively. On the other hand, $(j/f)^{1/3}$ performance of straight double side type decreases 19.7%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1256-1261
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• 2003

Since the viscous effect increases as the size of device decreases, viscous-driven micropump is a promising mechanism in microscale applications. In the present study, a dual-rotor type pump which contains two counter-rotating cylinders for improving performance characteristics is proposed. First, for flows in the single-rotor type pump, the present unstructured grid simulation method is validated by comparing its results to the previous results. Next, the performance of the dual-rotor type pump is evaluated by the parametric studies and is compared to that of the previous single-rotor type pump. The flow characteristics are qualitatively similar to those of single-rotor type pump. However, the performance of the micropump with tandem rotors is still better than that of previous pumping type, e.g. much larger flow rate, smaller driving region, higher efficiency, and wider operation range.