• 제목/요약/키워드: Thermodynamic mechanism

검색결과 168건 처리시간 0.021초

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) (Experimental Study on the Characteristics of Combustion in Indirect Moxibustion with Cake Insulation)

  • 이건휘;이건목;국우석
    • Journal of Acupuncture Research
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    • 제21권6호
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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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A MECHANISM OF THE STRANGE ISOTOPIC FRACTIONATION OF OXYGEN FOUND IN METEORITE AND LABORATORY

  • Yang, J.;Kim, S.K.;Soh, K.S.;Yee, J.H.;Kim, S.W.;Kim, K.H.;Yoo, K.W.
    • Journal of Astronomy and Space Sciences
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    • 제7권1호
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    • pp.1-10
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    • 1990
  • The thermodynamic distribution of the vibrational states of ozone coupled with anharmonic predissociation produces an unusual isotopomeric pattern of oxygen molecules. The model presented here explains the experimental data obtained from the electric discharge of oxygen gas to produce ozone condensed on a quartz at 77K.

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Peroxy Acid Oxidations: A Kinetic and Mechanistic Study of Oxidative Decarboxylation of $\alpha$-Keto Acids by Peroxomonophosphoric Acid

  • Radhasyam Panda
    • Bulletin of the Korean Chemical Society
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    • 제22권8호
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    • pp.909-913
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    • 2001
  • The kinetics of oxidative decarboxylation of pyruvic acid and benzoylformic acid by peroxomonophosphoric acid (PMPA) in aqueous medium have been investigated. The reaction follows second order-first order each in PMPA and substrate concentration a t constant pH. The reactivity of different peroxo species in the oxidation has been determined. Activation energy and thermodynamic parameters have been computed. A plausible mechanism consistent with the observed results is proposed.

Comparative study on Corrosion Inhibition of Vietnam Orange Peel Essential Oil with Urotropine and Insight of Corrosion Inhibition Mechanism for Mild Steel in Hydrochloric Solution

  • Bui, Huyen T.T.;Dang, Trung-Dung;Le, Hang T.T.;Hoang, Thuy T.B.
    • Journal of Electrochemical Science and Technology
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    • 제10권1호
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    • pp.69-81
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    • 2019
  • The corrosion inhibiting mechanism of Vietnam orange peel essential oil (OPEO) for mild steel in 1 N HCl solution was investigated elaborately. Corrosion inhibition ability of OPEO was characterized by electrochemical polarization, electrochemical impedance spectroscopy (EIS), and weight loss method. In the corrosive solution, OPEO worked as a mixed inhibitor and the inhibition efficiency of OPEO increased with the increase of its concentration. High inhibition efficiencies over 90% were achieved for the concentration of 3 - 4 g/L OPEO, comparable to that of 3.5 g/L urotropine (URO), a commercial corrosion inhibitor for acid media used in industry. By using adsorption isotherm models (Langmuir, Temkin and Frumkin), thermodynamic parameters of adsorption were calculated. The obtained results indicated physical adsorption mechanism of OPEO on the steel surface. The components responsible for the corrosion inhibition activity of OPEO were not only D-limonene, but also other compounds, which contain C=O, C=C, O-H, C-O-C, -C=CH and C-H bonding groups in the molecules.

볼텍스 튜브의 에너지 분리 현상에 관한 수치해석 연구 (Study of Energy Separation Mechanism in Vortex Tube by CFD)

  • 최원철;정명균
    • 대한기계학회논문집B
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    • 제32권2호
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    • pp.92-99
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    • 2008
  • The "energy separation phenomenon" through a vortex tube has been a long-standing mechanical engineering problem whose operational principle is not yet known. In order to find the operational principle of the vortex tube, CFD analysis of the flow field in the vortex tube has been carried out. It was found that the energy separation mechanism in the vortex tube consists of basically two major thermodynamic-fluid mechanical processes. One is the isentropic expansion process at the inlet nozzle, during which the gas temperature is nearly isentropically cooled. Second process is the viscous dissipation heating due to the high level of turbulence in both flow passages toward cold gas exit as well as the hot gas exit of the vortex tube. Since the amount of such a viscous heating is different between the two passages, the gas temperature at the cold exit is much lower than that at the hot exit.

Laves phase계 수소저장합금의 전기화학적 수소화 반응 매카니즘에 관한 연구 (A Study on the Electrochemical Hydrogenation Reaction Mechanism of the Laves Phase Hydrogen Storage Alloys)

  • 이지열;김찬중;김대용
    • 한국수소및신에너지학회논문집
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    • 제8권1호
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    • pp.31-41
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    • 1997
  • In order to investigate the mechanism of electrochemical hydrogenation reaction on Zr-based Laves phase hydrogen storage alloy electrodes, electrochemical charge/discharge characteristics, potentiostatic/dynamic polarizations and electrocehmical impedance spectroscopy(EIS) of Zr-Ti-Mn-Ni and Zr-Ti-Mn-Ni-M(M=Fe, Co, Al) alloys were examined. Electrochemical discharge capacities of the alloys were quite different with gas charge capacities. Therefore, it was considered that discharge capacities of the alloys depend on electrochemical kinetic factors rather then thermodynamic ones. Discharge efficiencies were increased linearly with exchange current densities. The results of potentiostatic/dynamic polarization measurements showed that electrochemical charge and discharge reaction of Zr-based Laves phase hydrogen storage alloys is controlled by charge transfer process at the electrode surface. The EIS measurements also confirmed this result.

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Spectrofluorometric Study of the Interaction of Coumarin Derivatives with Bovine Serum Albumin

  • Kamat, B.P.;Seetharamappa, J.;Kovala-Demertzi, D.
    • Journal of Photoscience
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    • 제11권2호
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    • pp.65-69
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    • 2004
  • The mechanism of interaction of four coumarin derivatives (CDS) with bovine serum albumin (BSA) was studied using spectrofluorometric technique. It was found that the coumarin ring common to all CDS makes major contribution to interaction. Binding affinities could be related to parachor values of CDS. Stem-Volmer plots indicated the presence of static component in the quenching mechanism. Results also showed that both tryptophan residues of protein are accessible to CDS. The high magnitude of rate constant of quenching indicated that the process of energy transfer occurs by intermolecular interaction forces and thus CDS binding site is in close proximity to tryptophan residues of BSA. Binding studies in the presence of the hydrophobic probe, 8-anilino-l-naphthalein-sulfonic acid showed that there is hydrophobic interaction between CDS and the probe and they do not share common sites in BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CDS to BSA involve hydrophobic bonds predominantly. The effects of various metal ions on the binding of CDS with BSA were also investigated.

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Ethanol-Water 溶液內에서의 p-Nitrobenzyl Chloride의 Solvolysis (Solvolysis of p-Nitrobenzyl chloride in the Ethanol-water Mixtures)

  • 이억석
    • 대한화학회지
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    • 제10권1호
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    • pp.11-14
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    • 1966
  • Ethanol-water mixture 內에서 일어나는 p-nitrobenzyl chloride의 solvolysis反應에 대한 熱力學的 parameter를 구하고 이 data를 ${\delta}_M{\Delta}H^{\neq} = a'Y + b{\delta}_M{\Delta}S^{\leq}$에 適用함으로써 反應常數 a'가 50% 이하의 alcohol solvent에서나 50% 이상의 solvent에서 같다는 것을 알 수 있었다. 즉 water-rich solvent에서나 alcohol-rich solvent에서나 solvolysis反應의 mechanism은 변함이 없다는 것을 알았다.

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Heavy metal adsorption of a novel membrane material derived from senescent leaves: Kinetics, equilibrium and thermodynamic studies

  • Zhang, Yu;Tang, Qiang;Chen, Su;Gu, Fan;Li, Zhenze
    • Membrane and Water Treatment
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    • 제9권2호
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    • pp.95-104
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    • 2018
  • Copper pollution around the world has caused serious public health problems recently. The heavy metal adsorption on traditional membranes from wastewater is limited by material properties. Different adsorptive materials are embedded in the membrane matrix and act as the adsorbent for the heavy metal. The carbonized leaf powder has been proven as an effective adsorbent material in removing aqueous Cu(II) because of its relative high specific surface area and inherent beneficial groups such as amine, carboxyl and phosphate after carbonization process. Factors affecting the adsorption of Cu(II) include: adsorbent dosage, initial Cu(II) concentration, solution pH, temperature and duration. The kinetics data fit well with the pseudo-first order kinetics and the pseudo-second order kinetics model. The thermodynamic behavior reveals the endothermic and spontaneous nature of the adsorption. The adsorption isotherm curve fits Sips model well, and the adsorption capacity was determined at 61.77 mg/g. Based on D-R model, the adsorption was predominated by the form of physical adsorption under lower temperatures, while the increased temperature motivated the form of chemical adsorption such as ion-exchange reaction. According to the analysis towards the mechanism, the chemical adsorption process occurs mainly among amine, carbonate, phosphate and copper ions or other surface adsorption. This hypothesis is confirmed by FT-IR test and XRD spectra as well as the predicted parameters calculated based on D-R model.

층층나무와 신갈나무 폐바이오매스를 활용한 수용액 중 납 제거 효율 및 기작 (Efficiency and Mechanism of Pb(II) Removal from Aqueous Solutions Using Cornus controversa and Quercus mongolica Biomass Waste)

  • 최시영;정석순;양재의;김혁수;조준형
    • 한국환경농학회지
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    • 제40권4호
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    • pp.239-247
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    • 2021
  • BACKGROUND: Enormous amounts of the wood biomass wastes have been produced through various wood processing. This study characterizes the surface characteristics of biomass powders of Cornus controversa (CC) and Quercus mongolica (QM) and investigates their removal efficiency and mechanism for Pb (II) in aqueous solution on which to base potential recycling alternative of the wood biomass. METHODS AND RESULTS: Batch experiments were conducted under different conditions of Pb concentrations, temperatures, time and solid/solution ratios. Adsorption isotherm of Pb by CC and QM biomass was explained significantly by the Langmuir model, indicating Pb was likely adsorbed on the monolayer of the surfaces. The adsorption kinetics were fitted significantly to the double first-order model consisting of rapid and slow steps. The respective rate constants (k1) of CC and QM for the rapid adsorption kinetic steps were 0.051 and 0.177 min-1, and most of the sorption reactions proceeded rapidly within 6-20 minutes. The maximum adsorption quantities (qmax) of Pb were 17.25 and 23.47 mg/g for CC and QM, respectively. Thermodynamic parameters revealed that adsorption of Pb on the biomass of CC and QM was a spontaneous endothermic reaction. CONCLUSION(S): Results demonstrate that biomass wastes of CC and QM can be used as Pb adsorbents judging from adsorption isotherm, kinetics, and thermodynamic parameters.