• Title/Summary/Keyword: Maximum effective temperature

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Experimental Study on the Characteristics of Combustion in Indirect Moxibustion with Garlic (마늘뜸의 연소특성에 관한 연구)

  • Lee, Geon-mok;Lee, Geon-hyee;Cho, Nam-geun;Park, So-young
    • Journal of Acupuncture Research
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    • v.21 no.4
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    • pp.31-51
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    • 2004
  • Objective: The propose of this study is to investigate the characteristics of combustion in indirect moxibustion with garlic. Methods: We observed the characteristics of combustion by the variations of the thickness(3mm, 4mm, 5mm) of a slice for indirect moxibustion with garlic and mass(80mg, 100mg, 120mg) of moxa cone and existence of holes. The temperature of indirect moxibustion for garlic insulation with holes was higher than temperature of indirect moxibustion for garlic insulation without holes. Combustions time in the preheating period is about 1 minute, it varies by the existence of holes, the thickness of a slice for indirect moxibustion with garlic, and the density of moxa cone. Results: Maximum temperature of heating period was $38.7{\sim}46.2^{\circ}C$, combustion time in the heating period was 118~164sec and maximum ascending temperature gradient was $0.102{\sim}0.264^{\circ}C/sec$. Retaining period was shorter than heating period and stimulus of heating retains more, because it is higher than body temperature. By this report, indirect moxibustion with garlic is more effective with holes and the appropriate thickness of a slice for indirect moxibustion with garlic is 3.5~4mm. It is appropriate that the diameter of moxa cone is 8mm and height of that is 10mm. With this condition, effective combustion period is 120sec, maximum temperature is $42{\sim}44^{\circ}C$, maximum ascending temperature gradient is $0.14{\sim}0.16^{\circ}C/sec$. It is necessary to study clinical correlations for more accurate quantitative standard.

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Combustion and Exhaust Emission Characteristics by the Change of Intake Air Temperature in a Single Cylinder Diesel Engine (단기통 디젤엔진에서 흡기온도변화에 따른 연소 및 배기특성)

  • Shin, Dalho;Park, Suhan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.3
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    • pp.336-343
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    • 2017
  • Intake air conditions, such as air temperature, pressure, and humidity, are very important parameters that influence engine performance including combustion and emissions characteristics. The purpose of this study is to investigate the effects of intake air temperature on combustion and exhaust emissions characteristics in a single cylinder diesel engine. In this experiment, an air cooler and a heater were installed on the intake air line and a gas flow controller was installed to maintain the flow rate. It was found that intake air temperature induced the evaporation characteristics of the fuel, and it affects the maximum in-cylinder pressure, IMEP(indicated mean effective pressure), and fuel consumption. As the temperature of intake air decreases, the fuel evaporation characteristics deteriorate even as the fuel temperature has reached the auto-ignition temperature, so that ignition delay is prolonged and the maximum pressure of cylinder is also reduced. Based on the increase in intake air temperature, nitrogen oxides(NOx) increased. In addition, the carbon monoxide(CO) and unburned hydrocarbons(UHC) increased due to incomplete fuel combustion at low intake air temperatures.

Evaluation of reactor pulse experiments

  • I. Svajger;D. Calic;A. Pungercic;A. Trkov;L. Snoj
    • Nuclear Engineering and Technology
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    • v.56 no.4
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    • pp.1165-1203
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    • 2024
  • In the paper we validate theoretical models of the pulse against experimental data from the Jozef Stefan Institute TRIGA Mark II research reactor. Data from all pulse experiments since 1991 have been collected, analysed and are publicly available. This paper summarizes the validation study, which is focused on the comparison between experimental values, theoretical predictions (Fuchs-Hansen and Nordheim-Fuchs models) and calculation using computational program Improved Pulse Model. The results show that the theoretical models predicts higher maximum power but lower total released energy, full width at half maximum and the time when the maximum power is reached is shorter, compared to Improved Pulse Model. We evaluate the uncertainties in pulse physical parameters (maximum power, total released energy and full width at half maximum) due to uncertainties in reactor physical parameters (inserted reactivity, delayed neutron fraction, prompt neutron lifetime and effective temperature reactivity coefficient of fuel). It is found that taking into account overestimated correlation of reactor physical parameters does not significantly affect the estimated uncertainties of pulse physical parameters. The relative uncertainties of pulse physical parameters decrease with increasing inserted reactivity. If all reactor physical parameters feature an uncorrelated uncertainty of 10 % the estimated total uncertainty in peak pulse power at 3 $ inserted reactivity is 59 %, where significant contributions come from uncertainties in prompt neutron lifetime and effective temperature reactivity coefficient of fuel. In addition we analyse contribution of two physical mechanisms (Doppler broadening of resonances and neutron spectrum shift) that contribute to the temperature reactivity coefficient of fuel. The Doppler effect contributes around 30 %-15 % while the rest is due to the thermal spectrum hardening for a temperature range between 300 K and 800 K.

Experimental Study on the Characteristics of Combustion in Indirect Moxibustion with Cake Insulation (격병구(隔餠灸)(부자구(附子灸),호초구(胡椒灸))의 연소특성(燃燒特性)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Lee, Geon-hui;Lee, Geon-mok;Guk, Uo-suk
    • Journal of Acupuncture Research
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    • v.21 no.6
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    • pp.233-248
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    • 2004
  • Objective : The purpose of this study is to investigate the mechanism and effect of moxibustion with monkshood cake, slice & black pepper cake. objectively, to be used as the quantitative data through the measurement of temperatqre, and to grasp the thermodynamic characteristics of moxibustion with monkshood cake, slice & black pepper cake. Methods : We have selected of the moxibustion with monkshood cake, slice & black pepper cake. indirect moxibustion. We make a comparative study of the thermodynamic characteristics of moxibustion with monkshood cake, slice & black pepper cake. We examined combustion times, temperatures, temperature gradients in each period during a combustion of moxa. Results & Conclusions : 1. We can design the moxibustion with monkshood cake that it has thermodynamic characteristics of 173sec effective combustion time, $44^{\circ}C$ maximum temperature, $0.22^{\circ}C/sec$ ascending maximum temperature, if we use 3mm thickness or 3mm and below of monkshood cake and the moxa cone is formed the conical shape that the base diameter was 8mm, the height was 10mm, the density was $600mg/cm^3$. 2. We can design the moxibustion with monkshood cake that it has thermodynamic characteristics of 205~271sec effective combustion period time, $44.6{\sim}46.1^{\circ}C$ maximum temperature, $0.18{\sim}0.24^{\circ}C/sec$ ascending maximum temperature, if we use 3mm thickness of monkshood cake and the moxa cone is formed the conical shape that the base diameter was 8mm, the height was 10mm, the density was $480{\sim}720mg/cm^3$.

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Calculation of Maximum Effective Temperature of Steel Box Girder Bridge Using Artificial Neural Network (인공신경망을 이용한 강박스거더의 유효온도 산정)

  • Lee, Seong- Haeng
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.96-103
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    • 2018
  • An analysis using a statistical method is generally used to determine the effective temperature based on the temperature design load of a bridge. In this study, the effective temperature was calculated by building an artificial neural network (ANN) capable of improving the statistical method. A Steel box girder bridge specimen was made with a width of 2.0 m, height of 2.0 m, and length of 3.0 m and 0.2 m the upper slab. Twenty one temperature gauges were attached to measure the temperature between 2014 and 2016 for three years. An ANN was learned using the data measured from 2014~2015 and the results were compared with the Euro codes. The error rate between the Euro code and statistical analysis values was analyzed to be 4.1 % for the total measurement point. The ANN was verified and the effective bridge temperatures were calculated using the temperature data measured in 2016. The results revealed an approximate 3.97 % difference from the statistical analysis values. This degree of error is considered to be acceptable in terms of engineering for the analysis of an ANN. An ANN can easily predict the effective temperature of a bridge by knowing the input values of the region's highest temperature, bridge type, and upper asphalt thickness when designing the bridge's temperature loads.

A Study on the Working Condition Effecting on the Maximum Working Temperature and Surface Roughness in Side Wall End Milling Using Design of Experiment (실험계획법을 이용한 엔드밀 가공 시 최대가공온도와 표면조도에 미치는 가공조건에 관한 연구)

  • Hong, Do-Kwan;Ahn, Chan-Woo;Baek, Hwang-Soon;Choi, Seok-Chang;Park, Il-Soo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.8 no.3
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    • pp.46-53
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    • 2009
  • To find the working condition is one of the important factors in precision machining. In this study, we analyzed maximum working temperature by infra-red camera and surface roughness in side wall end milling using design of experiment (DOE): RSM(response surface methodology), ANOM(analysis of means) and ANOVA(analysis of variance) by table of orthogonal array. ANOM and ANOVA are well adapted to select sensitivity of design variables for maximum working temperature and surface roughness. The effective design variables and their levels should be determined using ANOM, ANOVA. RSM is presented 2nd order approximation polynomial of maximum working temperature and surface roughness is composed with design variables. Therefore, it is expected that the proposed procedure using design of experiment : table of orthogonal array, ANOM, ANOVA and RSM can be easily utilized to solve the problem of working condition.

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Computation of Ionic Conductivity at NASICON Solid Electrolytes (II) Effects of mid-Na Sites on Na1-Na2 Conduction Paths (NASICON 고체 전해질의 이온 전도도 계산 (II) Na1-Na2 전도 경로에 미치는 mid-Na의 영향)

  • 최진삼;서양곤;강은태
    • Journal of the Korean Ceramic Society
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    • v.32 no.11
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    • pp.1292-1300
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    • 1995
  • The ionic conductivity of NASICON solid electrolytes was simulated by using Monte Carlo Method (MCM). There were included two conduction paths: (1) Na1-Na2 and (2) Na1-Na2 including Na2-Na2. We assumed that mid-Na ions provde an additional driving force for Na mobile ions due to the interionic repulsion between Na1 and Na2 ions. The inflection point of vacancy availability factor, V has been shown at nearby x=2, the maximum mid-Na ions. The inflection point of vacancy availability factor, V has been shown at nearby x=2, the maximum mid-Na sites are occupied. The effective jump frequency factor, V has been shown at nearby x=2, the maximum mid-Na sites are occupied. The effective jump frequency factor, W increased rapidly with the composition at low temperature, but decreased at high temperature region. On Na1-Na2 conduction path, the minimum of charge correlation factor, fc and the maximum of $\sigma$T were appeared at x=2.0. this indicated that mid-Na ions affect on the high ionic conductivity behavior. At the whole range of NASICON composition, 1n $\sigma$T vs. 1/T* plots have been shown Arrhenius behavior but 1n (VWFc) vs. 1/T* have been shown the Arrhenius type tendency at x=2, which mid-Na is being the maximum. The results of MCM agreed with the experimental one when the chosen saddle point value was 6$\varepsilon$ : 3$\varepsilon$. Here the calculated characteristic parameter of materials, K and the phase transition temperature were -4.001$\times$103 and 178$^{\circ}C$ (1/T*=1.92, 1000/T=2.22), respectively.

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Dynamic Recrystallization of Medium Carbon Steels (중탄소강의 동적 재결정에 관한 연구)

  • Kim S. I.;Han C. H.;Yoo Y. C.;Lee D. R.;Ju U. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.10a
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    • pp.33-36
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    • 2000
  • The dynamic recrystallization (DRX) of medium carbon steels (SCM 440 and POSMA45) was studied with torsion test in the temperature range of $900-1100^{\circ}C$ and the strain rate range of $5.0x10^{-2}\;-\;5.0x10^0/sec$. To establish the quantitative equations for DRX, the evolution of flow stress curve with strain was analyzed. The critical strain (${\varepsilon}_c$) and strain for maximum softening rate ( ${\varepsilon}^{*}$) could be confirmed by the analysis of work hardening rate ($d{\sigma}/d{\varepsilon}\;=\; \theta$). The volume fraction of dynamic recrystallization ($X_{DRX}$) as a function of processing variables, such as strain rate ( $\dot{\varepsilon}$ ), temperature (T), and strain ( $\varepsilon$ ) were established using the ${\varepsilon}_c$ and ${\varepsilon}^{*}$. For the exact prediction, the ${\varepsilon}_c$, ${\varepsilon}^{*}$ and Avrami' exponent (m') were quantitatively expressed by dimensionless parameter, Z/A respectively. The transformation-effective strain-temperature curve for DRX could be composed. It was found that the calculated results were agreed with the experimental data for the steels at any deformation conditions.

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Performance Characteristics of a Liquid-Metal Heat Pipe for igh-temperature Solar Thermal Devices Depending on the Operating Conditions (고온 태양열기기용 액체금속 히트파이프의 작동조건에 따른 성능 특성)

  • Park, Cheol-Min;Lee, Jung-Ryun;Boo, Joon-Hong;Kang, Yong-Heack
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.247-250
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    • 2009
  • Sodium heat pipe for high-temperature solar thermal application was manufactured and tested for transient and steady-state operations. Total length of the heat pipe was 650 mm and the outer diameter was 12.7 mm. Thermal performance was compared experimentally for two different cooling methods of the forced and the natural convection cooling in the heat pipe condenser. During the experiment, the maximum temperature was about 1300K, and different cooling methods were applied to the condenser region to charge the operating temperature. The effective thermal conductivity and the thermal resistance were investigated as a function of heat flux, heat transport length, and operating temperature.

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Temperature Effect-free Impedance-based Local Damage Detection (온도변화에 자유로운 임피던스 기반 국부 손상검색)

  • Koo, Ki-Young;Park, Seung-Hee;Lee, Jong-Jae;Yun, Chung-Bang
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.21-26
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    • 2007
  • This paper presents an impedance-based structural health monitoring (SHM) technique considering temperature effects. The temperature variation results in a significant impedance variation, particularly both horizontal and vertical shifts in the frequency domain, which may lead to erroneous diagnostic results of real structures. A new damage detection strategy has been proposed based on the correlation coefficient (CC) between the reference impedance data and a concurrent impedance data with an effective frequency shift which is defined as the shift causing the maximum correlation. The proposed technique was applied to a lab-sized steel truss bridge member under the temperature varying environment. From an experimental study, it has been demonstrated that a narrow cut inflicted artificially to the steel structure was successfully detected using the proposed SHM strategy.

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