간행물
한국기계기술학회지 KCI 등재 Journal of the Korean Society of Mechanical Technology 韓國機械技術學會誌
- 발행기관 한국기계기술학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1229-604X (Print)2092-0385 (Online)
- 수록기간 1999 ~ 2024
- 주제분류 공학 > 기계공학 공학 분류의 다른 간행물
- 십진분류KDC 550DDC 620
권호리스트/논문검색
제15권 제5호 (2013년 10월) 27건
21.
2013.10
구독 인증기관 무료, 개인회원 유료
In this study, the actual energy consumption of the secondary side of district heating system(DHS) with different hot water supply temperature control methods are compared. Two methods are outdoor temperature reset control and outdoor temperature predictive Control. While outdoor temperature reset control has been widely used for energy savings of the secondary side of the system, the results show that outdoor temperature predictive control method saves more energy. In general, outdoor temperature predictive control method is lowering the supply temperature of hot water, and it reduces standby losses and increases overall heat transfer value of heated spaces due to more flow into the space. During actual energy consumption monitoring, outdoor temperature predictive control method saves about 19.1% when it compared to outdoor temperature reset control method. Also, it is found that when partial load condition, such as daytime, the fluctuation of hot water supply temperature with outdoor temperature reset control is more severe than outdoor temperature prediction control. So, it proves that outdoor temperature prediction control is more stable even at partial load conditions.
4,000원
22.
2013.10
구독 인증기관 무료, 개인회원 유료
Lamb waves are extensively used in plate-like structure inspection because of their guided nature. However, their dispersive properties often limit their use in flaw detection and other applications. Dispersion weakens and defocuses interrogating Lamb waves and makes it difficult to accurately interpret signals reflected from defects or boundaries. Time reversal (TR) processing can be applied to compensate for the effect of dispersive Lamb waves. Thus, the TR operation will enable the amplification of dispersive Lamb wave signals by signal compression in time. In this study, experiments are performed in order to examine the refocusing and recovering the initial input waveform in the long range propagation of dispersive Lamb waves in a plate. Two different time reversal processes (regular TR and reciprocal TR or inverse filtering) are tested and the experimental results are compared
4,000원
23.
2013.10
구독 인증기관 무료, 개인회원 유료
The experiment was carried out during no-load condition for analysis of the relativity between MAP, hot film, oxygen, the secondary ignition and injector waveform. The experimental methods using oscilloscope were employed to measure waveform. The relativity between several waveform and the secondary waveform coming from ignition coil were measured in case of three decrepit vehicles. From these results, a summary of the important results are as follows. 1. Through fast acceleration experiments, the response time values of hot film sensor and oxygen sensor was faster than the those of the MAP sensor and oxygen sensor. 2. The values of spark line duration time was largest A, C, B type in the order named. And discharge energy of the secondary ignition waveform was largest A, B, C type 3. The value of effective discharge energy is to be nearly proportional to the spark line duration time. 4. The value of effective discharge energy directly increases as revolutions per minute increase, and the value of spark line duration time decreases as revolutions per minute increase.
4,000원
24.
2013.10
구독 인증기관 무료, 개인회원 유료
As the demand for car industry increase worldwide and car models diversify, industry of automobile parts also keep pace and grows day by day. However, since industry of automobile parts is staying small and there are only few study on basic knowledge of productivity, financial competitiveness is greatly insufficient. Among accessory processing, there are more parts such as key home or bolt hole rather than general turning operation, therefore, currently study on intermittence process is exigent. This thesis studied on machinability of Ductile cast iron(FCD 500) which is used for car break desk to help this kind of situation. Also it studied machinability by using Taguchi method which can get the best performance with few tests.
4,000원
25.
2013.10
구독 인증기관 무료, 개인회원 유료
Hydrogen has the very high heating value by comparing with other fuels and its combustion exhausts no carbon. But hydrogen causes the very high adiabatic flame temperature which generates thermal NOx. In this study, two cases of experiments were performed to compare engine characteristics. First and second cases are for only diesel combustion engine and mixed hydrogen diesel engine respectively. To verify the effect of mixed hydrogen-diesel combustion engine, the exhausted gas from modified dual fuel diesel engine was analyzed. In addition, diesel consumption per kWh for each case was estimated to validate its economic feasibility. By mixing hydrogen with 5kW brown(hydrogen-oxygen mixture) gas generator, the amount of CO(carbon mono-oxide) decreased from 330ppm to 210ppm by improving combustion and the amount of NOx increased from 390ppm to 520ppm by higher temperature of combustion chamber. Diesel consumption per kWh decreased from 450cc to 410cc but actually increased until 480cc because of the power of brown gas generator
4,000원
26.
2013.10
구독 인증기관 무료, 개인회원 유료
Experimental hot-water heating system was consisted of power supply equipment, a hot water storage tank, circulating pump, fan coil unit and a plastic flexible hose. This heating system was manufactured by an electric heater of a power capacity 6kw/h and light-oil hot air heater in control the heating capacity was 5,000kcal/h. As the result, temperature difference due to hot-water heating system and hot air heater in greenhouse showed that air temperature at experimental greenhouse, and comparison greenhouse were 14.8℃, 13.4℃ respectively. It was found that root-zone temperature of experimental plot and control were 22℃, 15℃. Root-zone temperature in the experimental plot was 7℃ higher than that in control. The inlet-outlet water temperature difference of 2℃ and 3℃ corresponded to the difference of the heat exchange of about 3,132kcal/h, 4,916kcal/h, the heat exchange effciency ranged from 54~88% generally. Under the experimental condition, equation heat change(Y) and correlation could be represented as follows : Y = -282.92ｘ2 + 2963.9ｘ -1688.6, R2 = 0.9081. it is suggested to applicate energy of root-zone warming system where energy from the groundwater is extracted and transferred to the water
4,000원
27.
2013.10
구독 인증기관 무료, 개인회원 유료
In this study, rye, Hairy beaches, pastures long and weighing many organic grazing cover crops can repress the uniforms, and the tractor was designed and built for mounting repression device. And identify appropriate working conditions and job factors and job performance by analyzing the correlation between the test results are as follows. Level 40∼50HP tractor for applying cover crops repression device width 2,400㎜, battling roller diameter is 380㎜, battling back after work uniforms repress blade for 4×100㎜, 640㎏ gross weight was optimized. Optimization of field test the tractor speed shift 1(0.45㎧∼0.53㎧) and in the repression and crop height 40∼ 60㎜ uniforms, respectively. Appropriate working conditions identified by weight in the roller by type by speed test results, the weight is heavy, long repression and squeezed me, speed was increased, the lower the efficiency of repression.
4,000원
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