• Title/Summary/Keyword: Mild

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CONVERGENCE OF EXPONENTIALLY BOUNDED C-SEMIGROUPS

  • Lee, Young S.
    • Korean Journal of Mathematics
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    • v.9 no.2
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    • pp.115-121
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    • 2001
  • In this paper, we establish the conditions that a mild C-existence family yields a solution to the abstract Cauchy problem. And we show the relation between mild C-existence family and C-regularized semigroup if the family of linear operators is exponentially bounded and C is a bounded injective linear operator.

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Corrosion Inhibition of Mild Steel in Acidic Medium by Jathropha Curcas Leaves Extract

  • Odusote, Jamiu K.;Ajayi, Olorunfemi M.
    • Journal of Electrochemical Science and Technology
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    • v.4 no.2
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    • pp.81-87
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    • 2013
  • Inhibition of corrosion of mild steel in sulphuric acid by acidic extract of Jatropha Curcas leaves has been studied using weight loss and thermometric measurements. It was found that the leaves extract act as a good corrosion inhibitor for mild steel in all concentrations of the extract. The inhibition action depends on the concentration of the Jatropha Curcas leaves extract in the acid solution. Results for weight loss and thermometric measurements indicate that inhibition efficiency increase with increasing inhibitor concentration. The adsorption of Jatropha curcas leaves extract on the surface of the mild steel specimens obeys Langmuir adsorption isotherm. Based on the results, Jatropha curcas leaves extract is recommended for use in industries as a replacement for toxic chemical inhibitors.

Numerical Investigation on the Thermal Characteristics of Mild Combustion According to Co-axial Air (동축공기에 따른 Mild 연소의 열적 특성에 대한 수치연구)

  • Hwang, Chang-Hwan;Baek, Seung-Wook;Kim, Hak-Young
    • Journal of the Korean Society of Combustion
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    • v.15 no.4
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    • pp.1-8
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    • 2010
  • Mild combustion is considered as a promising combustion technology for energy saving and low emission of combustion product gases. In this paper, the controllability of reaction region in mild combustion is examined by using co-axial air nozzle. For this purpose, numerical approach is carried out. Propane is considered for fuel and air is considered for oxidizer and the temperature of air is assumed 900K slightly higher than auto ignition temperature of propane. But unlike main air, the atmospheric condition of co-axial air is considered. Various cases are conducted to verify the characteristics of Co-Axial air burner configuration. The use of coaxial air can affect reaction region. These modification help the mixing between fuel and oxidizer. Then, reaction region is reduced compare to normal burner configuration. The enhancement of main air momentum also affects on temperature uniformity and reaction region. The eddy dissipation concept turbulence/chemistry interaction model is used with two step of global chemical reaction model.

A Comparison of the Performances of Confrontation Naming Test and Verbal Fluency Task in Patients with Prodromal Alzheimer's Disease and Mild Alzheimer's Disease (노인성 알츠하이머병 위험군과 초기 알츠하이머병 환자의 이름대기와 구어유창성 능력의 비교)

  • Choi, Hyun-Joo
    • Speech Sciences
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    • v.15 no.2
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    • pp.111-118
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    • 2008
  • We identified the characteristic impairmants of linguistic semantic memory in patients with prodromal Alzheimer's disease(AD) and mild AD. To elucidate the earliest changes of semantic language function in subjects with AD, performances on confrontation naming test and verbal fluency task were compared among patients with AD patients (n=20), mild AD patients (n=27) and healthy elderly controls (n=20). Tasks in this study included the confrontation naming test of Test of Lexical Processing in Aphasia(TLPA/Japanese) and one-minute verbal fluency task (semantic/ phonetic categories). The results were as follows: 1) Performances of the prodromal AD group showed the comparable to those of the control group on the confrontation naming test, 2) In the semantic/phonetic verbal fluency tasks, the performances of the control group were better than those of the prodromal AD and mild AD groups, but no significant differences were shown between the prodromal AD and the mild AD group.

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Multi-environment PDF Modeling for MILD Combustion Processes (Multi-environment PDF 모델을 이용한 MILD 연소과정 해석)

  • Ji, Hyunggeun;Jeon, Sangtae;Kim, Yongmo
    • Journal of the Korean Society of Combustion
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    • v.22 no.4
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    • pp.43-50
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    • 2017
  • In this study, the multi-environment probability density function(MEPDF) approach has been applied to numerically investigate Delft-Jet-in-Hot-Coflow(DJHC) turbulent flames under Moderate or Intense Low-oxygen Dilution (MILD) combustion condition. Computations are made for two different jet velocities(Re = 4100 and 8800). In terms of mean axial velocity, temperature, and turbulent kinetic energy, numerical results are in reasonably good agreements with experimental data even if there exist the noticeable deviations in downstream region. Based on numerical results, the detailed discussions are made for the essential features of the non-visible flame structure and MILD combustion processes.

Inhibiting Effect of Nicotinic Acid Hydrazide on Corrosion of Aluminum and Mild Steel in Acidic Medium

  • Bhat, J. Ishwara;Alva, Vijaya D.P.
    • Journal of the Korean Chemical Society
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    • v.58 no.1
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    • pp.85-91
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    • 2014
  • The corrosion behavior of aluminum and mild steel in hydrochloric acid medium was studied using a nicotinic acid hydrazide as inhibitor by potentiodynamic polarization, electrochemical impedance spectroscopy technique and gravimetric methods. The effects of inhibitor concentration and temperature were investigated. The experimental results suggested, nicotinic acid hydrazide is a good corrosion inhibitor for both aluminum and mild steel in hydrochloric acid medium and the inhibition efficiency increased with increase in the inhibitor concentration. The polarization studies revealed that nicotinic acid hydrazide exhibits mixed type of inhibition. The inhibition was assumed to occur via adsorption of the inhibitor molecules on the aluminum and mild steel surface and inhibits corrosion by blocking the reaction sites on the surface of aluminum.

The Effect of Polya's Heuristics in Mathematical Problem Solving of Mild Disability Students (경도장애 학생들의 수학적 문제해결을 위한 폴리아의 전략 효과 연구)

  • Han, Kyung-Hwa;Kim, Young-Ok
    • East Asian mathematical journal
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    • v.32 no.2
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    • pp.253-289
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    • 2016
  • This study attempted to figure out new teaching method of mathematics teaching-learning by applying Polya's 4-level strategy to mild disability students at the H Special-education high school where the research works for. In particular, epilogue and suggestion, which Polya stressed were selected and reconstructed for mild disability students. Prior test and post test were carried by putting the Polya's problem solving strategy as independent variable, and problem solving ability as dependent variable. As a result, by continual use of Polya's program in mathematics teaching course, it suggested necessary strategies to solve mathematics problems for mild disability students and was proven that Polya's heuristic training was of help to improve problem solving in mathematics.

Computational Study of the MILD Combustion and Pollutant Emission Characteristics in Jet Flow Field (제트 유동장에서의 마일드 연소 및 오염물질 배출특성에 관한 전산해석 연구)

  • Kim, Yu Jeong;Song, Keum Mi;Oh, Chang Bo
    • Journal of the Korean Society of Combustion
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    • v.17 no.4
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    • pp.60-65
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    • 2012
  • The MILD combustion and pollutant emission characteristics were investigated computationally. The temperature of supplying air-stream and mixing rate (${\Omega}$) of exhaust gas in the air-stream were adjusted to investigate the effects of those parameters on the MILD combustion in jet flow field. The emission indices for NO (EINO) and CO (EICO) were introduced to quantify the amount of those species emitted from the combustion. The high-temperature region disappeared gradually as the mixing rate increased for fixed air-stream temperature. The EINO increased as the air-stream temperature became higher for fixed mixing rate, and the EINO decreased dramatically with increasing the mixing rate for each air-stream temperature condition. The EICO also decreased with increasing the mixing rate and it was nearly independent of air-stream temperature except for near ${\Omega}$ = 0.7. It was found that the CO supplied in the air-stream can be destroyed in the MILD combustion over the certain mixing rate.

The effect of fuel/oxygen jet impingement on MILD combustion (연료/산소 Jet Impingement에 의한 MILD 연소)

  • Lee, Ho Yeon;Cha, Chun Loon;Lee, Pil Hyong;Hwang, Sang Soon;Lee, Sung Ho;Yoo, In
    • 한국연소학회:학술대회논문집
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    • 2015.12a
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    • pp.309-311
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    • 2015
  • The MILD(Moderate or Intense Low-oxygen Dilution) combustion has been considered as one of the promising combustion technology for high thermal efficiency and low emissions. In this paper, the effect of fuel oxygen impingement on formation of MILD combustion was analyzed using numerical simulation. This investigation was simulated under the thermal intensity $0.04MW/m^3$ and equivalence ratio 0.91. The results show that the temperature distribution was become relatively uniform and the amount of CO emission was decreased as the increase of oxygen jet velocity and impinging angle.

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