• Title/Summary/Keyword: Accelerating Rate

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The Effects of Air Injection in Compressor Exit on the Response Performance of a Turbocharged Diesel Engine under the Operating Conditions of Rapid Acceleration. (터보과급디젤기관의 급가속 운전시 압축기출구에의 공기분사가 응답성능에 미치는 영향)

  • 박상규;최낙정
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.6
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    • pp.110-119
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    • 2000
  • In this paper, an experimental study is carried out under the operating conditions of low speed and rapid acceleration in order to investigate and improve the response characteristics of a turbocharged diesel engine with radial turbine driven by exhaust gas. A rapid acceleration for investigating the response performance is applied to the fuel-pump rack of the engine from 0-10% to 0-40% in steps of 10%, and accelerating time of 1, 2 and 3 seconds is applied to the engine. Further experiment for improving the low speed torque and acceleration performance is also performed by means of injecting air into the inlet manifold at compressor exit during the period of low speed and application of a rapid acceleration. The effects of air injection on the response performance are represented at subjected engine speed with the changes of response performance factors such as air injection pressure, air injection period, accelerating rate, accelerating time and load. From the experimental results obtained throughout this study, it is shown that air injection into the inlet manifold at compressor exit is closely related to the improvement of low speed and acceleration performance of a turbocharged diesel engine.

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Rate-acceleration of TEMPO-mediated Polymerization of Styrene in the Presence of Various Acids

  • Hong, Chang-Kook;Jang, Heang-Sin;Hong, Sang-Hyun;Shim, Sang-Eun
    • Macromolecular Research
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    • v.17 no.1
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    • pp.14-18
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    • 2009
  • The acceleration effect of various organic acids, such as methanesulfonic acid (MSA), ethanesulfonic acid (ESA), 4,4'-sulfonyldibenzoic acid (SDA), diphenylacetic acid (DPAA), and $\rho$-toluenesulfonic acid (TSA), on the rate of styrene bulk polymerization with 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) and benzoyl peroxide (BPO) was investigated. The addition of organic acids significantly accelerated the rate. Among these organic acids, DPAA showed an efficient rate-accelerating effect with living nature of polymerization. When DPAA was used as a rate-accelerating additive for TEMPO-mediated living free radical polymerization (LFRP), the rate of polymerization was dramatically enhanced, the linearity of reaction kinetics was successfully maintained, and the polydispersity was effectively controlled.

A Fundamental Study on the Steel Corrosion Due to Carbonation of Concrete (콘크리트의 중성화로 인한 철근의 부식에 관한 기초적 연구)

  • 이창수;윤인석;최성기
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.203-206
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    • 1998
  • In reinforced concrete carbonation of concrete leads to depassivation of the reinforcement, and hence to initiation of corrosion. As a result of carbonation accelerating experiment with using effect of wet-dry cycle and 15% concentration of CO ₂, the carbonation rate shows very distinct difference according to W/C ratio. OPC-40 estimated no carbonation depth, whereas OPC-60 estimated rapidly the carbonation rate. The comparative analysis of the carbonation rate accelerating depends on different kinds of cement shows fastest FAC-20. Also, highly W/C ratio's concrete shows low half-cell potential value and fast corrosion rate. During period for 14 weeks. corrosion rate was not severe. So, it can be concluded that only carbonation attack on concrete doesn't severly deteriorated except very poor qualitified concrete.

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The Properties of Early Strength of Concrete Containing Slag and Fly-ash for In-situ Application (현장 적용을 위한 3성분계 콘크리트의 조기강도 특성)

  • Jung Chul-Hee;Kim Kyoung-Min;Lee Jin-Woo;Bae Yeon Ki;Lee Jae-Sam
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.497-500
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    • 2005
  • This study was performed to evaluate the characteristics which are slump, air content and time of set in fresh concrete and compressive strength of hardened concrete containing slag powder and fly-ash. Replacement rate of FA is fixed on 10$\%$ and replacement rate of slag powder are 0$\%$, 20$\%$ and 30$\%$. Also AE water-reducing agents(standard type, accelerating type) are used. The results were as follows. (1)Slump flow of concrete using AE water-reducing agents is similar. Flowability is incresed when replacement rate of slag powder is increased due to slag powder's ball bearing reaction.(2)Time of set of concrete using accelerating type agent is more faster than that of concrete using standard type agent because of ettringite generation that promote setting.(3)Early strength of three-component concrete using accelerating type agent is higher than that using standard type agent. Therefore cumulative pore is reduced due to ettringite

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Field Test of Energy Storage System on Urban Transit System (도시철도용 에너지저장시스템 에너지 절감을 현장시험)

  • Lee, Han-Min;Kim, Gil-Dong;An, Cheon-Heon;Kim, Young-Gyu;Kim, Tae-Seok
    • Proceedings of the KSR Conference
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    • pp.1461-1467
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    • 2009
  • The electric railway is a clean and energy saving system, because it requires relatively less energy than automobiles by transporting the same passengers or goods. Six thousands of vehicles are operated on Korean urban transit system. This system is 95% of regeneration system. Especially, the VVVF-Inverter vehicle has a merit of the highest regeneration rate. Energy consumption is 90% for traction and 10% for auxiliary supply. Braking energy is about 40% of energy consumption. Up to 40% of the tractive power of vehicles capable of returning energy to the power supply can be regenerated during braking and that this energy can be used to feed vehicles which are accelerating at the same time. The energy generated by braking vehicle would simply be converted into waste heat by its braking resistors if no other vehicle is accelerating at exactly the same time. Such synchronized braking and accelerating can not be coordinated, the ESS(energy storage system) stores the energy generated during braking and discharges it again when a vehicle accelerates. This paper presents field tests about the energy saving rate of the developed ESS. when the ESS is on/off, energy saving rate of the ESS is tested. The verification test in the field focused on energy saving.

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A Study on the Dynamic Characteristics of a Turbocharged Diesel Engine (터보 과급 디젤 기관의 동특성에 관한 연구)

  • Choi, N.J.;Lee, C.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.1
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    • pp.143-154
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    • 1995
  • This study investigates the response characteristics of a four-cylinder four-stroke turbocharged diesel engine by using computer simulation and experiments when a rapid acceleration is applied to the fuelpump rack. In the theoretical analysis, linearization method is used to avoid the difficulty on the complex nonlinear functions. Comppressor exit pressure, pressure and temperature of turbine inlet, and turbocharger speed are chosen as the independent variables of transfer functions which represent the dynamic characteristics of the turbocharger system, and expressed as the functions with respect to the time. Experiments on the same eigine system are also carried out to prove the validity of theoretical study. Further, this study carried an experiment for improving transient response performance by injecting air into the inlet manifold under the rapid accelerating conditions. The effects of air injection on the response performances are also represented at varying conditions such as injection pressure, injection period, accelerating rate, accelerating time, engine speed and load.

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Monitoring of Deforestation Rate and Trend in Sabah between 1990 and 2008 Using Multitemporal Landsat Data

  • Osman, Razis;Phua, Mui-How;Ling, Zia Yiing;Kamlun, Kamlisa Uni
    • Journal of Forest and Environmental Science
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    • v.28 no.3
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    • pp.144-151
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    • 2012
  • Deforestation is a major and very critical problem faced by many tropical countries including Malaysia. Sabah is the second largest state in Malaysia and its deforestation rate has been accelerating. This study was conducted to monitor the deforestation in Sabah in the last two decades with Landsat images of 1990, 2000 and 2008. Supervised classification with maximum likelihood algorithm was conducted using the Landsat data for monitoring deforestation. In total, between 1990 and 2008, Sabah lost half of its intact forest, or more than 1.85 million ha in less than two decades. Overall, the deforestation rate for all forest types combined for the last two decades was 1.6% per year. Deforestation seemed to be accelerating because the deforestation rate between 1990 and 2000 was 0.9% per year and it had increased to 2.7% per year between 2000 and 2008. The deforestation trend seemed to follow a negative exponential from 1990 to 2008. In contrast, the agricultural areas increased rapidly with a total of increment more than 1 million ha. This confirmed that agriculture especially establishment of commercial plantation was the major factor of deforestation in Sabah for the last two decades.

CO2 Emission Considering Condition of Vehicle Acceleration (차량 가속특성에 따른 이산화탄소(CO2) 배출량 비교)

  • Joo, Jin Yun;Oh, Heung Un
    • International Journal of Highway Engineering
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    • v.17 no.3
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    • pp.125-132
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    • 2015
  • PURPOSES : The present study aims to evaluate the added $CO_2$ emissions incurred from accelerating operation when to increase the speed up to the allowed level. METHODS : The methodology used are basically the relationship between emission rates and vehicle speeds or acceleration rate. These rates together are used to calculate the added $CO_2$ emissions incurred from accelerating operation. RESULTS : It was resulted that the all the emission rates are increasing proportionally to vehicle speeds or acceleration rates. Additionally, it was also resulted that allowable speeds increasing, the added emission rates are increasing rapidly. CONCLUSIONS : It may be concluded that if the allowable speed ranges are managed, $CO_2$ emissions during vehicle operation are much reduced. From this reason, it was found that the allowable speed during highway design and operation would be much necessary

The Application to Sand Spreading Method for Accelerating Sedimentation and Self-Weight Consolidation of Dredged Soils (준설토의 침강.자중압밀촉진을 위한 모래살포공법의 적용성에 관한 연구)

  • 양상호;김재권;심성현;김수삼
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.767-772
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    • 2003
  • The clay which transported into a pond under the high water content condition have no effective stress which develop from the starting point of sedimentation and self-weight consolidation. Since sedimentation and self-weight consolidation dependent on self-weight of solids is made progress over a long time, to accelerating it have many advantages in the economic view In this paper, sand spreading method which is one of sedimentation and self-weight consolidation acceleration method is studied through a series of experiments considering the mixing ratio of sand and clay. The test results show that the mixing ratio of clay and sand of 1:0.2 is the biggest rate of consolidation and the pouring at the end point of sedimentation considerably effects on consolidation rate.

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ETCHING CHARACTERISTICS OF MAGNETIC THIN FILMS BY ION BEAM TECHNIQUE

  • Lee, H.C.;Kim, S.D.;Lim, S.H.;Han, S.H.;Kim, H.J.;Kang, I.K.
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.538-542
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    • 1995
  • The etching characteristics of magnetic thin films of permalloy and Fe-based alloys are investigated. The thin films are fabricated by rf magnetron sputtering and the substrates used are silicon and glass. Etching is done by ion beam technique and the main process parameters investigated are beam voltage, beam current and accelerating voltage. The etch rate of the magnetic films is proportional to the beam current, but it is not directly related to the accelerating voltage and beam voltage. The dependence of etch rate on the process parameters can be explained by ion current density. It is found that the ion beam etching is effective in obtaining well-developed micro-patterns on the permalloy and Fe- based magnetic thin films.

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