• Title/Summary/Keyword: rate equation

Search Result 2,981, Processing Time 0.029 seconds

Assessment of Slip Sinkage of an Off-Road Tracked Vehicle from Model Track Experiments (모형궤도시험을 통한 야지궤도차량의 슬립침하 평가)

  • Baek, Sung-Ha;Shin, Gyu-Beom;Chung, Choong-Ki
    • Journal of the Korean Geotechnical Society
    • /
    • v.34 no.6
    • /
    • pp.49-59
    • /
    • 2018
  • When a tracked vehicle travels off-road, shearing action and ground sinkage occur on the soil-track interface and severely affect tractive performance of the tracked vehicle. Especially, the ground sinkage, which is induced by vehicle's weight (hereinafter referred to as static sinkage) and longitudinal forces in the direction of travel producing slip (hereinafter referred to as slip sinkage), develops soil resistance, directly restricting the tractive performance of an off-road tracked vehicle. Thus, to assess the tractive performance of an off-road tracked vehicle, it is imperative to take both of static sinkage and slip sinkage into consideration. In this research, a series of model track experiments was conducted to investigate the slip sinkage which has not been clarified. Experiment results showed that the slip sinkage increased with increasing the slip ratio, but the increasing rate gradually decreased. Also, the slip sinkage was found to increase as relative density of soil decreased and imposed vertical load increased. From the experiment results, the normalized slip sinkage defined as slip sinkage to static sinkage calculated in the identical condition was investigated, and an empirical equation for the slip sinkage was developed in terms of slip ratio, which allows vehicle operators to predict the slip sinkage in a given soil and operating conditions.

Study on the Desulfurization Characteristic of Limestone Depending on the Operating Parameters of In-Furnace Desulfurization for Oxy-Fuel Combustion Using Drop Tube Furnace (순산소연소 조건에서 Drop tube furnace를 이용한 운전변수에 따른 석회석의 탈황특성 연구)

  • Choi, Wook;Jo, Hang-Dae;Choi, Won-Kil;Park, Yeong-Sung;Keel, Sang-In;Lee, Hyung-Keun
    • Korean Chemical Engineering Research
    • /
    • v.49 no.6
    • /
    • pp.857-864
    • /
    • 2011
  • Oxy-fuel combustion with many advantages such as high combustion efficiency, low flue gas flow rate and low NOx emission has emerged as a promising CCS technology for coal combustion facilities. In this study, the effects of the direct sulfation reaction on $SO_2$ removal efficiency were evaluated in a drop tube furnace under typical oxy-fuel combustion conditions represented by high concentrations of $CO_2$ and $SO_2$ formed by gas recirculation to control furnace combustion temperature. The effects of the operating parameters including the reaction temperature, $CO_2$ concentration, $SO_2$ concentration, Ca/S ratio and humidity on $SO_2$ removal efficiency were investigated experimentally. $SO_2$ removal efficiency increased with reaction temperature up to 1,200 due to promoted calcination of limestone reagent particles. And $SO_2$ removal efficiency increased with $SO_2$ concentrations and the humidity of the bulk gas. The increase of $SO_2$ removal efficiency with $CO_2$ concentrations showed that $SO_2$ removal by limestone was mainly done by the direct sulfation reaction under oxy-fuel combustion conditions. From the impact assessment of operation parameters, it was shown that these parameters have an effects on the desulfurization reaction by the order of the Ca/S ratio > residence time > $O_2$ concentration > reaction temperature > $SO_2$ concentration > $CO_2$ concentration > water vapor. The semi-empirical model equation for to evaluate the effect of the operating parameters on the performance of in-furnace desulfurization for oxy-fuel combustion was established.

Adsorption Equilibrium, Kinetics and Thermodynamics Studies of Malachite Green Using Zeolite (제올라이트를 이용한 말라카이트 그린의 흡착평형, 동력학 및 열역학 연구)

  • Lee, Jong-Jib
    • Clean Technology
    • /
    • v.18 no.1
    • /
    • pp.76-82
    • /
    • 2012
  • The paper includes utlization of zeolite as potential adsorbent to remove a hazardous malachite green from waste water. The adsorption studies were carried out at 298, 308 and 318 K and effects of temperature, contact time, initial concentration on the adsorption were measured. On the basis of adsorption data Langmuir and Freundlich adsorption isotherm model were also confirmed. The equilibrium process was described well by Freundlich isotherm model, showing a selective adsorption by irregular energy of zeolite surface. From determined isotherm constants, zeolite could be employed as effective treatment for removal of malachite green. From kinetic experiments, the adsorption process followed the pseudo second order model, and the adsorption rate constant ($k_2$) decreased with increasing initial concentration of malachite green. Thermodynamic parameters like activation energy, change of free energy, enthalpy, and entropy were also calculated to predict the nature adsorption. The activation energy calculated from Arrhenius equation indicated that the adsorption of malachite green on the zeolite was physical process. The negative free energy change (${\Delta}G^{\circ}$ =-6.47~-9.07 kJ/mol) and the positive enthalpy change (${\Delta}H^{\circ}$ = +32.414 kJ/mol) indicated the spontaneous and endothermic nature of the adsorption in the temperature range 298~318 K.

Growth curve estimates for wither height, hip height, and body length of Hanwoo steers (Bos taurus coreanae)

  • Park, Hu-Rak;Eum, Seung-Hoon;Roh, Seung-Hee;Sun, Du-Won;Seo, Jakyeom;Cho, Seong-Keun;Lee, Jung-Gyu;Kim, Byeong-Woo
    • Korean Journal of Agricultural Science
    • /
    • v.44 no.3
    • /
    • pp.384-391
    • /
    • 2017
  • Growth curves in Hanwoo steers were estimated by Gompertz, Von Bertalanffy, Logistic, and Brody nonlinear models using growth data collected by the Hanwoo Improvement Center from a total of 6,973 Hanwoo (Bos taurus coreanae) steers 6 to 24 months old that were born between 1996 and 2015. The data included three parameters: A, mature size of body measurement; b, growth ratio; and, k, intrinsic growth rate. Nonlinear regression equations for wither height according to Gompertz, Von Bertalanffy, Logistic, and Brody models were $Y_t=144.7e^{-0.5869e^{-0.00301t}}$, $Y_t=145.3(1-0.1816e^{-0.00284t})^3$, $Y_t=143.1(1+0.7356e^{-0.00352t})^{-1}$, and $Y_t=146.8(1+0.4700e^{-0.00249t})^1$, respectively, while those for hip height were $Y_t=144.5e^{-0.5549e^{-0.00312t}}$, $Y_t=145.0(1-0.1724e^{-0.00295t})^3$, $Y_t=143.1(1+0.6863e^{-0.00360t})^{-1}$, and $Y_t=146.2(1+0.4501e^{-0.00263t})^1$, respectively. Equations for body length $Y_t=174.1e^{-0.8342e^{-0.00289t}}$, $Y_t=175.8(1-0.2500e^{-0.00265t})^3$, $Y_t=170.0(1+1.1548e^{-0.00363t})^{-1}$, and $Y_t=180.3(1+0.6077e^{-0.00215t})^1$, respectively, for the same models. Among the four models, the Brody model resulted in the lowest mean square error, with mean square errors of 31.79, 30.57, and 42.13, respectively, for wither height, hip height, and body length. Also, an estimated birth wither height, birth hip height, and birth body length (77.98, 80.57, and 70.97 cm, respectively) were lower in the Brody model than in other models. An inflection point was not observed during the growth phase of Hanwoo steer according to the growth curves calculated using Gompertz, Von Bertalanffy, and Logistic models. Based on the results, we concluded that the regression equation using the Brody model was the most appropriate among the four growth models. To obtain more accurate parameters, however, using data from a wider production period (from birth to shipping) would be required, and the development of a suitable model for body conformation traits would be needed.

Estimation of Road Capacity at Two-Lane Freeway Work Zones Considering the Rate of Heavy Vehicles (중차량 비에 따른 편도 2차로 고속도로 공사구간 도로 용량 추정)

  • Ko, Eunjeong;Kim, Hyungjoo;Park, Shin Hyoung;Jang, Kitae
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.19 no.2
    • /
    • pp.48-61
    • /
    • 2020
  • The objective of this study is to estimate traffic capacity based on the heavy-vehicle ratio in a two-lane freeway work zone where one lane is blocked by construction. For this, closed circuit television (CCTV) video data of the freeway work zone was collected, and the congestion at an upstream point was observed. The traffic volume at a downstream point was analyzed after a bottleneck was created by the blockage due to the upstream congestion. A distribution model was estimated using observed-time headway, and the road capacity was analyzed using a goodness-of-fit test. Through this process, the general capacity and an equation for capacity based on the heavy-vehicle ratio passing through the work zone were presented. Capacity was estimated to be 1,181~1,422 passenger cars per hour per lane (pcphpl) at Yeongdong, and 1,475~1,589pcphpl at Jungbu Naeryuk. As the ratio of heavy vehicles increased, capacity gradually decreased. These findings can contribute to the proper capacity estimation and efficient traffic operation and management for two-lane freeway work zones that block one lane due to a work zone.

Organizational Culture and Community-Centered Social Inclusion Orientation Among Social Service Organizations for People with Disabilities: Focused on Market Orientation As a Mediator (장애인복지기관의 조직문화유형과 지역사회중심사회통합지향성에 관한 연구 : 시장지향성의 매개효과를 중심으로)

  • Choi, Jae-Sung;Choi, Jung-Ah;Jung, So-Yon
    • Korean Journal of Social Welfare
    • /
    • v.61 no.1
    • /
    • pp.5-32
    • /
    • 2009
  • The purpose of this study is to examine the effects of organizational culture types (rational culture, developmental culture, group culture, and hierarchical culture) on Community-Centered Social Inclusion Orientation(COSI) among social service organizations for people with disabilities. More specifically, this study developed and empirically tested two theoretical models where each of organizational culture types were hypothesized to affect COSI either directly or indirectly through market orientation. For data collection, self-administered type questionnaires were mailed to 416 social service organizations for people with disabilities across the nation and 293 responded (response rate: 70.4%) from June 1 to September 22, 2006. For analysis, however, only 263 respondents were used, excluding Independent living centers due to their small size and short history. Structural Equation Modeling was employed for analysis and Full Information Maximum Likelihood was used for estimation. Findings indicated that market orientation had a significant effect on COSI. In addition, developmental culture and hierarchical culture were found to affect COSI directly while rational culture and group culture were found to affect COSI indirectly through market orientation. These findings imply that market orientation needs to be emphasized as a strategy in order to enhance social inclusion orientation for those organizations. Given that all the four types of organizational culture have direct or indirect impacts on COSI, those organizations are also advised to develop the four types of organizational culture harmoniously rather than one single type of organizational culture.

  • PDF

(Photosensitive Polymers VII) Mechanism of Photosensitized Curing Reaction of Cinnamoylated Polymers ((感光性 高分子에 關한 硏究 VII) Cinnamoylated Polymers의 光增感 硬化反應機構)

  • Kim, Kwang-Sup;Shim, Jyong-Sup
    • Journal of the Korean Chemical Society
    • /
    • v.10 no.4
    • /
    • pp.166-174
    • /
    • 1966
  • The multistep mechanism of photosensitized curing reaction cinnamoylated photosensitive polymer is proposed from the energy level diagram of cinnamic acid and sensitizer, and from the fact that excess of sensitizer brings the sensitivity to a limiting value etc. Various factors which have effects on the ability of sensitizer are also discussed. The mechanism involves following steps: activation to the first excited singlet states of cinnamoyl group(C) and sensitizer(S) by their absorption of photon, their intersystem crossing to the lowest triplet state, bimolecular internal quenching by formation of excimer of sensitizer, triplet excitation energy transfer and intermolecular addition between cinnamoyl group in ground state and that in triplet state. The rate equation derived from this mechanism is $-\frac{d[C]}{dt} = \frac{K_1[C]}{K_2 + [C]}[\frac{I^c_{abs}}{K_3 + [S]} + \frac{K_4[C]}{(K_5 + [C])(K_6 + [S])}(I^s_{abs} + \frac{K_7I^c_{abs}[S]}{K_8 + [S]})]$ where $I^c_{abs}\;and\;I^s_{abs}$: the rates of absorption of photon by cinnamoyl group and sensitizer $K_n$: Constants. It is proved with the cinnamate of poly(glyceryl phthalate)(PGC) in the absence of sensitizer using the infrared analytical method and successfully applied for the experimental data reported on the effects of the degree of cinnamoyl esterification and the concentration of sensitizer upon the sensitivity.

  • PDF

Modeling of Medium Temperature Drops of the Elevated-bench Hydroponics for Strawberry Cultivation during Low Temperature Season (저온기 딸기 고설 수경재배시 온실기온에 따른 배지내 온도강하 모델 개발)

  • Park, Jae-Wan;Ha, Yu-Shin;Kim, Ki-Dong;Park, Dae-Heum;Lee, Ki-Myung;Jun, Ha-Joon;Kwon, Soon-Gu;Choi, Won-Sik;Chung, Sung-Won
    • Journal of Bio-Environment Control
    • /
    • v.19 no.3
    • /
    • pp.123-129
    • /
    • 2010
  • A study on modeling of medium temperature drops of the elevated-bench hydroponic system for strawberry cultivation during low temperature season was conducted. Four different conditions were used for the experiment. These consisted of two kinds of bed types (plant, V), four kinds of medium (rice, perlite, rice hulls80% and peatmoss20%, perlite80% and peatmoss20%), two kinds of mulched bed (mulched, non mulched) and four kinds of greenhouse air temperature (l.5, 3.2, 5.0, $6.7^{\circ}C$), and the results were summarized as follows: Temperature drop of medium in the V-bed was slower than that in the plant bed, showing better insulation effect of V-bed. Temperature drop of medium with mulching on the top of the bed was slower than the case without mulching, as a result, the beneficial effect of temperature drop was appeared in mulched bed. Linear regression of the temperature descent rate and the temperature difference between medium and air showed significant correlation. The regression equation for the Pearlite80% and Peatmoss20% in the V-bed was f(x) = -0.2656 + 0.1345x at the $R^2$ of 0.9269. Using the model, the temperature drop during night can be predicted for the various media at the different depths.

Differences in Panicle Structure and Spikelet Degeneration in Two Different Types of Rice Cultivars; Milyang 23 and Koshihikari (벼 품종 밀양 23호와 고시히카리의 수형태와 영화 퇴화 차이)

  • 강시용
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.42 no.6
    • /
    • pp.833-840
    • /
    • 1997
  • Differentiation and degeneration of spikelets in paddy rice has been studied in high yielding Indica$\times$Japonica hybrid cultivar, Milyang 23 and a Japonica type cultivar, Koshihikari. Germinated seeds planted in 5000$^{-1}$ a pots filled with submerged soil and cultured under natural conditions. The young panicles of main stem were continuously dissected and observered by Cryo-SEM from the panicle initiation stage, and investigated about formation position of the differentiation and degeneration spikelet within a panicle of 7 days after heading. The degeneration of spikelet appeared simultaneously throughout panicle just after closure of spikelet by the palea and lemma. Differentiated and degenerated spikelets per panicle were about 240, 80 for Milyang 23 and 87, 6 for Koshihikari, respectively. The spikelets degeneration in Milyang 23 was mainly on the secondary and tertiary branch which were developed from primary branch of middle-basal panicle node and hardly not the spikelets of primary branch, and degeneration rate of secondary and tertiary rachis branch and spikelets for Milyang 23 were 2.5 times greater than those of Koshihikari. The proper relation equation between total differentiation or normal spikelets number per panicle(Y) and each rachis branch number were different between cultivars, Le., Y=5.5X$_1$+3.0X$_2$ for Koshihikari as previously proposed, but those of Milyang 23, Y=5.7X$_1$+3.5X$_2$+2.8X$_3$ for total differentiation spikelets and Y=5.6X$_1$+3.2X$_2$+2.4X$_3$ for normally developed spikelets, where X$_1$, X$_2$, X$_3$ are number of primary, secondary, tertiary rachis branch, respectively.

  • PDF

CAVITY FORMATION IN INTERFACE BETWEEN POWER LAW CREEP PARTICLE AND ELASTIC MATRIX SUBJECTED TO A UNIAXIAL STRESS

  • Lee, Yong-Sun;Ha, Young-Min;Hwang, Su-Chul
    • Journal of Theoretical and Applied Mechanics
    • /
    • v.1 no.1
    • /
    • pp.69-88
    • /
    • 1995
  • The paper attempts to estimate the incubation time of a cavity in the interface between a power law creep particle and an elastic matrix subjected to a uniaxial stress. Since the power law creep particle is time dependent, the stresses in the interface relax. Through previous stress analysis related to the present physical model, the relaxation time is defined by ${\alpha}$2 which satisfies the equation $\Gamma$0 |1+${\alpha}$2k|m=1-${\alpha}$2 [19]. $\Gamma$0=2(1/√3)1+m($\sigma$$\infty$/2${\mu}$)m($\sigma$0/$\sigma$$\infty$tm) where $\sigma$$\infty$ is an applied stress, ${\mu}$ is a shear modulus of a matrix, $\sigma$$\infty$ is a material constant of a power law particle, $\sigma$=$\sigma$0 $\varepsilon$ and t elapsed time. the volume free energy associated with Helmholtz free energy includes strain energies associated with Helmholtz free energy includes strain energies caused by applied stress anddislocations piled up in interface (DPI). The energy due to DPI is found by modifying the results of Dundurs and Mura[20]. The volume free energies caused by both applied stress and DPI are a function of the cavity size(${\gamma}$) and elapsed time(t) and arise from stress relaxation in the interface. Critical radius ${\gamma}$ and incubation time t to maximize Helmholtz free energy is found in present analysis. Also, kinetics of cavity fourmation are investigated using the results obtained by Riede[16]. The incubation time is defied in the analysis as the time required to satisfy both the thermodynamic and kinetic conditions. Through the analysis it is found that [1] strain energy caused by the applied stress does not contribute significantly to the thermodynamic and kinetic conditions of a cavity formation, 2) in order to satisfy both thermodynamic and kinetic conditions, critical radius ${\gamma}$ decreases or holds constant with increase of time until the kinetic condition(eq.40) is satisfied. Therefore the cavity may not grow right after it is formed, as postulated by Harris[11], and Ishida and Mclean[12], 3) the effects of strain rate exponent (m), material constant $\sigma$0, volume fraction of the particle to matrix(f) and particle size on the incubation time are estimated using material constants of the copper as matrix.