• Title/Summary/Keyword: Effect of Operating Conditions

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A Study on the Effects of Small Enterprise Start-up Preparatory Factors on Business Performance

  • Kim, Seung-Hee;Kim, Young-Ki;Choi, Shin-Hea
    • The Journal of Industrial Distribution & Business
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    • v.8 no.5
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    • pp.23-33
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    • 2017
  • Purpose - The present study aims to examine the relationship between small enterprise start-up preparatory factors and increases in sales and operating profits, which are business performances utilizing the National Survey of Actual Conditions of Small Enterprises conducted by the Small Enterprise, Market Service. Research design, data, and methodology - Start-up preparatory factors were divided into six types; business type, start-up history, start-up motives, preparatory periods, and start-up funds to figure out the relationship between sales and operating profits with regression analyses. Regression analyses were conducted based on the foregoing with a view to identifying the effects of start-up preparatory factors on business performance. Results - Since start-up preparatory factors generally affect business performance, it was identified that start-up preparatory factors importantly affect operating profits and sales, which are business performances. However, start-up preparatory periods and the implementation of education among preparatory activities were shown to have no effect on business performances, and the effect of the ratio of start-up fund provided by the founder on operating profits was shown to be not significant. Conclusions - The present study comprehensively examined those start-up preparatory factors that have positive effects on business performances after start-up. The present study is meaningful in that it can provide positive implications for efficient start-up of small enterprises hereafter.

Effects of Freezing Conditions on the Concentration-Efficiency in the Progressive Freeze-Concentration (Progressive Freezing에 의한 동결 농축법에 있어서의 농축효과에 미치는 동결조건의 영향)

  • 배승권
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.24 no.6
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    • pp.984-989
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    • 1995
  • The concentration-efficiencyh of blue dextran solution in the progressive freeze-concentration was related to the freezing conditions such as the freezing speed and the stirring speed in the solution phase. From the theoreticla balance equation of heat and mass transfer at freezing front, the relationship between the freezing conditions and the ice structure at freezing front was drived. A high freeze-concentration efficiency was obtained under the operating conditions represented by a low speed of freezing and a high speed of stirring. The operating conditions were related to a smooth solid-liquid interface and these results were well explained by the theoretical equation. Effect of the solute component size on the concentration efficiency in the progressive freezeconcentration was also tested. The concentration efficiency of latex particles showed a lower value than that of blue dextran, however, its difference was insignificant.

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Evaluation of influent changing effect on the STP performance using Dr. Wastewater (Dr. Wastewater program의 적용을 통한 하수처리장 운전에 미치는 유입수 변동 영향평가)

  • Kim, Youn Kwon;Kim, Hong Suck;Seo, In Seok;Kim, Byung Goon;Han, In Sun;Kim, Jin Sang
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.6
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    • pp.647-655
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    • 2008
  • Sewer Rehabilitation Project (SRP) is planed, designed and constructed to perform its intended performance as sewerage delivery systems. Recently, a subject of performance evaluation methodology development for SRP has become a great deal of concern among researchers in Korea. From the view point of Sewage Treatment Plant (STP), however, the estimation of improvement efficiency for SRP is in lack of reliability due to the fact that affections for the treatment efficiency and operating condition are not reflected on SRP design and construction. In this study, statistical methodology was used in the analysis of data, which are taken during 1,186 days ($1^{st}$ Jan. 2005 - $31^{th}$ Mar. 2008) from the influent, effluent and operating conditions of full-scale STP($25,000m^3/d$). Then the effect of SRP on the influent characteristics and operating conditions changing was compared and evaluated. Results from the statistical evaluation show that SRP causes characteristic changes in influent and exerts a significant effect especially on the performance of STP.

Thermodynamic Analysis of an Absorption Heat Pump Heating System with LiBr-Water Solution (2 중효용 흡수식 히트점프의 난방 성능 해석)

  • Won, S.H.;Lee, W.Y.;Chung, H.S.
    • Solar Energy
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    • v.9 no.3
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    • pp.73-80
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    • 1989
  • This paper presents as assessment based on steady-state thermodynamic analysis and computer modeling of a double effect generation absorption heating cycle for solar air-conditioning to find operating temperature ranges. The influences of component temperatures on the heating coefficients of performance and mass flow ratio have been investigated to obtain optimum operating conditions for the proposed air conditioning system. And the single and double effect absorption cycles are compared with each other over the same range of temperatures.

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Experimental Study on Added Resistance of VLCC for Ship's Operating Condition in Waves

  • Lee, Sang-Min
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.3
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    • pp.240-245
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    • 2015
  • In this study, experiments were performed using a model of a very large crude oil carrier (VLCC), which is a typical blunt ship, in a wave-making towing tank. The aim of the experiments was to determine the effect of added resistance in waves on the various operating conditions of a VLCC. An analysis of the results was conducted to determine the characteristics of resistance performance in waves. In addition, the characteristics of added resistance on a tanker were analyzed under irregular waves based upon the above result. The experimental results showed that added resistance was the highest around ${\lambda}/L=1.0$, and the added resistance increased with the increase of the ship speed. Furthermore, under even keel conditions, the added resistance was higher than that under the trim changes, and the smallest added resistance was measured at the trim by the stern. Based on the experimental results, this study proposes effective operating conditions by analyzing the characteristics of the mean added resistance and the expected extreme response in irregular waves.

Analysis of Strain Gauge Data Onboard the IBRV ARAON during Icebreaking Voyage in the Antarctic Sea Ice (쇄빙연구선 ARAON호의 남극해 쇄빙운항 중 계측된 스트레인게이지 데이터 분석)

  • Cheon, Eun-Jee;Choi, Kyungsik;Kim, Ho-Yeon;Lee, Tak-Kee
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.6
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    • pp.489-494
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    • 2014
  • Estimation of correct ice load under various operating conditions is important during the design and the operation stages of an icebreaker. Normal operating conditions are expected from the official field ice trials and also from general ice transit action. In this paper ice load for the Korean icebreaking research vessel, ARAON, under normal operating condition, is discussed. Published ice load data from full-scale sea trials of six icebreakers were analysed to derive an empirical ice load prediction formula. The IBRV ARAON had sea ice trials during 2010 and 2012 summer season. Strain gauge signal were recorded during her icebreaking voyage and the measured strain data were converted to the equivalent hull stress values. The effect of ARAON's speed in ice and the hull stresses are investigated. By comparing the empirical formula and ice load calculation based von measured data, it is recommended to use the empirical ice load estimation formula for the initial design stage.

Numerical Analysis of Performance of Linear Compressor for the Stilting Cryocooler (스터링 냉동기의 선헝압축기 운전특성에 관한 수치해석적 연구)

  • 홍용주;박성제;김효봉;염한길;최영돈
    • Progress in Superconductivity and Cryogenics
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    • v.4 no.2
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    • pp.58-62
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    • 2002
  • The purpose of this study is to analyze the charging gas effect on the resonance and performance characteristics of the linear compressor for small scale FPFD Stirling refrigerator. To ensure high performance of FPFD type Stirling refrigerator, the operating frequency of the refrigerator should be around the natural frequency of compressor. The gas spring effect which is induced from Pressure change in cylinder due to motion of pistons has significant effect on the natural frequency of the compressor. The numerical results show the linear compressor has high natural frequency when the charging pressure of working fluid is high and the stroke of compressor, current, input power and efficiency of compressor were shown with different operating conditions.

Simulation of the Characteristics of High-Performance Absorption Cycles (고성능 흡수냉동 사이클의 특성 시뮬레이션)

  • 윤정인;오후규;이용화
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.231-239
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    • 1995
  • This paper describes a computer simulation of the triple effect, water-lithium bromide absorption cooling cycles. The performance of the absorption systems is investigated through cycle simulation to obtain the system characteristics with the cooling water inlet temperature, the working solution concentrations, the ratio of the amount of the weak solution to the high, middle and low temperature generators, and the temperature difference of each solution heat exchanger. The efficiency of different cycles has been studied and the simulation results show that higher coefficient of performance could be obtained for the parallel cycle of constant solution distribution rate. As a result of this analysis, the optimum designs and operating conditions were determined based on the operating conditions and coefficient of performance.

Effect of Operating Conditions on Characteristics of Combustion in the Pulverized Coal Combustor (미분탄 연소로의 운전조건이 연소특성에 미치는 영향)

  • Kang, Ihl-Man;Kim, Ho-Young
    • 한국연소학회:학술대회논문집
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    • 1999.10a
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    • pp.139-148
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    • 1999
  • In oder to analyze the effect of operating conditions on pulverized coal combustion, a numerical study is conducted at the pulverized coal combustor. Eulerian approach is used for the gas phase, whereas Lagrangian approach is used for the particle phase. Turbulence is modeled using standard ${\kappa}-{\varepsilon}$ model. The description of species transport and combustion chemistry is based on the mixture fraction/probability density function(PDF) approach. Radiation is modeled using P-l model. The turbulent dispersion of particles is modeled using discrete random walk model. Swirl number of secondary air affects the flame front, particle residence time and carbon conversion. Primary/Secondary air mass ratio also affects the flame front but little affects the carbon conversion and particle residence time. Air-fuel ratio only affects the flame front due to lack of oxygen. Radiation strongly affects the flame front and gas temperature distribution because pulverized coal flame of high temperature is considered.

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