• Title/Summary/Keyword: Intrinsic Rate

Search Result 345, Processing Time 0.029 seconds

Impact of Internal/External Diffusion on Gasification Reaction Rate Analysis of Coal Char in High Temperatures and Elevated pressures (고온/고압 조건에서의 석탄 촤 내부 및 외부 가스화 반응효과)

  • Kim, Gyeong-Min;Kim, Jin-Ho;Lisandy, Kevin Yohanes;Kim, Ryang-Gyoon;Kim, Gyu-Bo;Jeon, Chung-Hwan
    • Journal of the Korean Society of Combustion
    • /
    • v.21 no.4
    • /
    • pp.23-29
    • /
    • 2016
  • Reactivity of gasification defined by bouardard reaction is critical parameter in efficiency of the gasifier. In this study, char reactivity of the gasification was derived from the experiments using the intrinsic reaction kinetics model. Pressurized wire mesh heating reactor (PWMR) can produce high temperature and high pressure conditions up to 50 atm and 1750 K, respectively and PWMR was designed to evaluate the intrinsic reaction kinetics of $CO_2$ gasification. In this study, Kideco and KCH (sub-bituminous Indonesian coal) were pulverized and converted into char. Experiments used the PWMR were conducted and the conditions of the temperature and pressure were 1373~1673 K, 1~40 atm. To distinguish the pressure effect from high pressurized condition, internal and external effectiveness factors were considered. Finally, the intrinsic kinetics of the Kideco and KCH coal char were derived from $n^{th}$ order reaction rate equations.

Intrinsic and Thermodynamic Effects on the Structure and Energy of the S$_N$2 Transition State$^*$

  • Lee, Ik-Choon;Seo, Heon-Su
    • Bulletin of the Korean Chemical Society
    • /
    • v.7 no.6
    • /
    • pp.448-453
    • /
    • 1986
  • Two contributions to the activation barrier of the $S_N2$ reaction, intrinsic and thermodynamic, are discussed in connection with the predictive power of various rate-equilibrium relationships. It has been shown that the PES models can only give correct predictions of changes in structure and energy of the transition state if the activation barrier is dictated by the thermodynamic factor. We concluded that the identity and dissociative $S_N2$ reactions are dominated by the intrinsic component while associative $S_N2$ reactions are predominantly of thermodynamic controlled. Thus in the former cases, the PES models fail, whereas in the latter cases predictions based on the intrinsic factor, the quantum mechanical models, fail. Finally in a general case of equal contributions by thermodynamic and intrinsic factors, the $SN_2$ reaction proceeds by a synchronous process with zero net charge on the reaction center, for which predictions of substituent effects will be the same as for the intrinsic control case.

Primary Effects of Ozone on MUsca domestica L. (오존이 집파리 個體群에 미치는 一次的 效果에 관한 硏究)

  • 최덕일;공동수;이해풍
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.7 no.2
    • /
    • pp.119-126
    • /
    • 1991
  • Air pollution is directly and indirectly associated with the toxicology through the increase of mortality, the decrease of oviposition rate, and the decline of insect population, as well as the disruption of equilibria with higher or lower trophic levels. To investigate intrinsic decrease rates, oviposition period, and emerging rates of pupae of house fly under air pollution stresses, healthy individuals of Musca domestica L. were collected in the field, cultured in the laboratory for 2 $\sim$ 3 generations, and artificially exposed to $O_3 (4 ppm) in automatically controlled air pollutant fumigation chambers. Results from this study are summarized as follows: 1. Survivorship curves of both control group and exposed groups of healthy house fly to 4 ppm $O_3$ have linearly or stair-like decreasing trends of revers S-shape. 2. For cohorts exposed to 4 ppm of $O_3$, intrinsic decrease rate of cohort exposed for 2 hours significantly increases compared to that of control group, slight increases were observed for those exposed for 4 hours and 8 hours, which shows no distinct relationships between exposure period and intrinsic decrease rate. 3. While the numbers of pupae of exposed cohorts increase with the increase of exposure period, emerging rate shows a distinct decrease. 4. The relationships between emerging rate (E) of pupae and the exposure period (T) for cohorts exposed to 4 ppm of $O_3$ are expressed with the equation, E (%)=21.027 - 7.942 ln (T).

  • PDF

A Study on the Pattern and Extent of Washer Use in Household (가계의 세탁기사용방식과 사용정도에 관한 연구)

  • 김선미;이기영
    • Journal of Families and Better Life
    • /
    • v.7 no.2
    • /
    • pp.95-107
    • /
    • 1989
  • In this study one aspect of consumer behavior in household equipment utilization was investigated the pattern, frequency, rate of washer use and their relation to the following factors a) Washer related factors : extent of the presence of desired characteristics, the evaluation of washer's intrinsic features and related household facilities. b) Psycho-social factors : attitude of energy conservation, preference & ability to wash by hand, standard of washing of the respondent homemaker. c) Socio-demographic factors : age, education level and employment status of homemaker, house-hold income, the presence of children under seven years, size of family, the presence of a paid help. The subjects of this study were 286 homemakers with washer in Seoul. Analysis methods were used to fuequency, one-way ANOVA, Gamma test, Pearson's Correlation Coefficient, t-test and multiple regression of SPSS program. The major findings are the following; 1) The pattern, frequency, rate of washe use appeared various in every household. 2) Extent of the presence of desired characteristics was very low and respondents evaluated their washer's intrinsic features moderate. 3) The pattern of washer use was affected by the evaluation of washer's intrinsic features, preference & ability to wash by hand, wife's employment and household income. The frequency of washer use was affected by family size and preference & ability to wash by hand. The rate of washer use was affected by extent of the presence of desired characteristics, the evaluation of washer's intrinsic features and preference & ability to wash by hand. Therefore, washing by hand is major substitute for washer. If more desired characteristics are added to washer, intrinsic features are improved, and maintenance costs are reduced or household income is raised, every houshold with washer will use washer more than washing by hand in washing ask so that it may gain more utility from washer.

  • PDF

The Effect of Substrate Surface Roughness on In-Situ Intrinsic Stress Behavior in Cu Thin Films (기판 표면 조도에 따른 구리박막의 실시간 고유응력 거동)

  • Cho, Moohyun;Hwang, Seulgi;Ryu, Sang;Kim, Youngman
    • Korean Journal of Metals and Materials
    • /
    • v.47 no.8
    • /
    • pp.466-473
    • /
    • 2009
  • Our group previously observed the intrinsic stress evolution of Cu thin films during deposition by changing the deposition rate. Intrinsic stress of Cu thin films, which show Volmer-Weber growth, is reported to display three unique stress stages, initial compressive, broad tensile, and incremental compressive stress. The mechanisms of the initial compressive stress and incremental compressive stages remain subjects of debate, despite intensive research inquiries. The tensile stress stage may be related to volume contraction through grain growth and coalescence to reduce over-accumulate Cu adatoms on the film surface. The in-situ intrinsic stresses behavior in Cu thin films was investigated in the present study using a multi-beam curvature measurement system attached to a thermal evaporation device. The effect of substrate surface roughness was monitored by observed the in-situ intrinsic stress behavior in Cu thin films during deposition, using $100{\mu}m$ thick Si(111) wafer substrates with three different levels of surface roughness.

Life Table Descriptions of Tetrastichus sp. (Hymenoptera: Eulophidae) on Hyphatria cunea Drury

  • Lee, Jang-Hoon;Lee, Ki-Sang;Lee, Hai-Poong
    • Animal cells and systems
    • /
    • v.6 no.1
    • /
    • pp.19-22
    • /
    • 2002
  • Life table studies were conducted in the laboratory for the eulophid gregarious pupal parasitoid, Tetrastichus sp., on Hyphantria cunea Drury at a constant temperature of 28.2$\pm$2$^{\circ}C$, 50-60% RH to evaluate their impact on the host and their potential biological control. Development of immature stage took 20.1$\pm$2.7 d: adult females lived for 23.2$\pm$2.2 (range, 16-27)d and produced a mean of 53.6$\pm$26.6 adult progeny per female, with a sex ratio of 1: 9.5 (M:F). The intrinsic rate of natural increase (r$_{m}$) was 0.178/ female/day; the net reproductive rate (R$_{o}$), 46.74; the capacity for increase (r$_{c}$) 0.177; the finite rate of increase (λ) 1.19/female/day; thus each female contributed 46.74 individuals to the population in a mean generation time of 21.6 d. Biological factors in determining the life history trait variation of the parasitoid were discussed.d.d.d.

Bridging Service Employee's Intrinsic Motivation and Job Performance : A Moderated Mediation Model (중국 서비스 종업원의 내재적 동기와 종업원 창의성, 직무성과 : 동료지원의 조절적 매개모형)

  • Kang, Seongho;Hur, Won-Moo
    • Journal of Distribution Science
    • /
    • v.16 no.5
    • /
    • pp.71-81
    • /
    • 2018
  • Purpose - Our research aims to investigate the mediating effect of employee creativity on the relationship between intrinsic motivation and job performance using relationship using Chinese department salespeople samples. Another objective of this study is to be clear boundary conditions that strengthen or weaken the effects of intrinsic motivation on work outcomes (i.e., employee creativity and job performance). Drawing on JD-R theory, we suggest that the two types of coworker support play differential moderating roles in the intrinsic motivation, employee creativity relationship by increasing or decreasing job resources and demands in different ways. Research design, data, and methodology - This empirical study data were collected from gathered from a sample of full time salespeople in China. A total of 550 questionnaires were distributed and 300 responses were collected, indicating a response rate of 84.0%. Working with a sample of 300 salespeople working in a department store in China. SPSS 18.0, Process 2.16 Macro, and M-Plus 8.0 software were used in the data analysis. Descriptive statistics were used to evaluate the distribution of the employee profiles and correlations between variables. M-Plus 8.0 software was used to test the model fit, validity and reliability of the variables. Finally, all research hypotheses was estimated by SPSS Macro 2.16. Results - To test our research hypotheses, we employed an analytical strategy suggested by Hayes (2013; 2015) and Shrout and Bolger (2002). In this study, we tested the relationship between intrinsic motivation and job performance throughout employee creativity. Results showed intrinsic motivation and job performance was partially mediated by employee creativity. The positive relationship between intrinsic motivation and employee creativity when coworker emotional support was high than when it was low. In contrast, the positive association between intrinsic motivation and employee creativity was stronger when coworker instrumental support was low than when it was high. Coworker emotional and instrumental support further moderated the indirect effect of intrinsic motivation on job performance through employee creativity. Conclusions - This study extends the conceptual model and empirical researches in coworker supports literature by representing a fundamental mechanism of how salespeople's intrinsic motivation and job performance throughout employee creativity.

A Study of Intrinsic Alpha Rhythm, Electroencephalography, and Heart Rate Variability Index as Indicators of Cognitive Function and Health in Elderly Adults (노년기 인지기능 및 건강상태를 반영하는 지표로써 Alpha 고유리듬과 뇌파 및 HRV 지표와의 관계 연구)

  • Shim, Jun-Young
    • Science of Emotion and Sensibility
    • /
    • v.22 no.3
    • /
    • pp.21-34
    • /
    • 2019
  • This study was an examination of the relevance and clinical significance of electroencephalographic (EEG) indexes (e.g., mental/physical stress and attention) and indexes of heart rate variability (HRV) with regard to cognitive function and physiological health conditions in elderly people. A device was used to record two-channel EEGs of the frontal lobe and a one-channel ECG simultaneously. Subjects were 76 people average aged 73. The significant findings are as follows: First, subjects whose intrinsic alpha rhythm had high amplitude, regardless of peak, showed higher resistance to mental stress and lower physical stress than did subjects with low-amplitutde intrinsic alpha rhythm. Second, HRV, SDNN, and RMSSD indexes showed strong positive correlations between the two groups of subjects regardless of the division of groups. Third, the alpha asymmetry of the left and right sides of the brain in subjects with low-amplitude intrinsic alpha rhythm was larger, and the delta/alpha ratio (reflecting physical stress) and theta/sensorimotor rhythm (SMR) ratio (showing the decline in attention) were bigger. Fourth, the subjects in whom intrinsic alpha rhythm peak occurred during slow rhythm had a higher theta/SMR ratio than did subjects whose peak occurred during fast rhythm, which was related to a steeper decline in attention. Therefore, the presence or absence of intrinsic alpha rhythm peak and amplitude on quantitative EEG may be an index reflecting the cognitive function and physiological health of elderly people.

A Study on the Hydriding Reaction Characteristics and the Change of the Hydriding Reaction Rates of MmNi4.5Al0.5 during Temperature-Induced Cycling (MmNi4.5Al0.5의 수소화 반응특성 및 Temperature-Induced Cycling에 따른 수소화 반응속도의 변화에 관한 연구)

  • Kim, Soo-Ryoung;Lee, Jai-Young
    • Journal of Hydrogen and New Energy
    • /
    • v.1 no.1
    • /
    • pp.1-8
    • /
    • 1989
  • The hydriding kinetic mechanism and the change of the hydriding reaction rate of $MmNi_{4.5}Al_{0.5}$ during the thermally induced hydrogen absorption-desorption cycling are investigated. Comparison of the reaction rate data which are obtained by the pressure sweep method with the theoretical rate equations suggests that the hydriding rate controlling step has changed from the dissociative chemisorption of hydrogen molecules at the surface to the hydrogen diffusion through the hydride phase with the increase of the hydriding fraction. These hydriding kinetic mechanism is not changed during the cycling. However, the intrinsic hydriding reaction rate of $MmNi_{4.5}Al_{0.5}$ after 5500 cycles increases significantly comparing with the activated one. It is suggested that the change of the hydriding kinetic behavior due to intrinsic degradation of $MmNi_{4.5}Al_{0.5}$ can be interpreted as follows ; the formation of nickel cluster at the surface of the sample and the host metal atom exchange in bulk by thermal cycling.

  • PDF