• Title/Summary/Keyword: Kinetic Property

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Kinetic Data for Texture Changes of Foods During Thermal Processing

  • Lee, Seung Hwan
    • Food Engineering Progress
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    • v.21 no.4
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    • pp.303-311
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    • 2017
  • To automate cooking processes, quantitative descriptions are needed on how quality parameters, such as texture change during heating. Understanding mechanical property changes in foods during thermal treatment due to changes in chemical composition or physical structure is important in the context of engineering models and in precise control of quality in general. Texture degradation of food materials has been studied widely and softening kinetic parameters have been reported in many studies. For a better understanding of kinetic parameters, applied kinetic models were investigated, then rate constants at $100^{\circ}C$ and activation energy from previous kinetic studies were compared. The food materials are hardly classified into similar softening kinetics. The range of parameters is wide regardless of food types due to the complexity of food material, different testing methods, sample size, and geometry. Kinetic parameters are essential for optimal process design. For broad and reliable applications, kinetic parameters should be generated by a more consistent manner so that those of foods could be compared or grouped.

Applicability of adsorption kinetic model for cation/anion for chitosan hydrogel bead (키토산비드를 이용한 양이온/음이온의 흡착모델 적용)

  • An, Byungryul
    • Journal of Korean Society of Water and Wastewater
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    • v.33 no.3
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    • pp.205-213
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    • 2019
  • Batch adsorption tests were performed to evaluate the applicability of adsorption kinetic model by using hydrogel chitosan bead crosslinked with glutaraldehyde (HCB-G) for Cu(II) as cation and/or phosphate as anion. Pseudo first and second order model were applied to determine the sorption kinetic property and intraparticle and Boyd equation were used to predict the diffusion of Cu(II) and phosphate at pore and boundary-layer, respectively. According to the value of theoretical and experimental uptake of Cu(II) and phosphate, pseudo second order is more suitable. On comparison with the value of adsorption rate constant (k), phosphate kinetic was 2-4 times faster than that of Cu(II) at any experimental condition indicating the electrostatic interaction between ${NH_3}^+$ and phosphate is dominated at the presence of single component. However, when Cu(II) and phosphate simultaneously exist, the value of k for phosphate was sharply decreased and then the difference was not significant. Both diffusion models confirmed that the sorption rate was controlled by film mass transfer at the beginning time (t < 3 hr) and pore diffusion at next time section (t > 6 hr).

Property Evaluation of Kinetic Sprayed Al-Ni Composite Coatings (저온 분사 공정을 통하여 형성된 Al/Ni 복합소재 코팅의 특성 평가)

  • Byun, GyeongJun;Kim, JaeIck;Lee, Changhee;Kim, SeeJo;Lee, Seong
    • Journal of Welding and Joining
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    • v.32 no.5
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    • pp.72-79
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    • 2014
  • Shaped charge(SC) ammunition is a weapon that penetrates directly the target by made jet from metal liner on impacting at a target. In SC, the liner occupies significantly important role causing an explosion and penetration of the target. The Al-Ni composite coating was deposited on copper liner in a solid state via kinetic spraying to improve the explosive force. The mechanical properties, reactivity and microstructure were investigated to confirm the possibility of kinetic sprayed Al/Ni composite coating as a reactive liner material. Reactive liner using Al/Ni composite exhibited much enhanced reactivity than pure copper liner due to Self-propagating High-temperature Synthesis (SHS) reaction with significantly improved adhesive bond strength. Especially, among the Al/Ni composite coatings, AN11 (the Al versus Ni atomic percent ratio is 1:1) showed the greatest reactivity due to its widest reaction area between deposited Al and Ni.

Effect of Slurry Property on Preparation of Zirconia Film in Electrophoretic Deposition (전착법에서 용액특성이 지르코니아 막형성에 미치는 영향)

  • 김상우;이병호;손용배;송휴섭
    • Journal of the Korean Ceramic Society
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    • v.36 no.9
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    • pp.991-996
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    • 1999
  • Effect of solution property on the weight varation and microstructural change of film was studied by electrophoretic deposition in order to obtain a homogeneous and dense zirconia film. As a result of weight kinetics of film which obtained in alcohol or aqueous solution having different polarity experimental data showed large deviation from theoretical ones calculated by Zhang's kinetic model. It had been shown that the weight affecting factors was largely dependent on properties other than dielectric constant and viscosity of solvent zeta potential appiled field and time. In initial stage a main factor of the drastic weight increase was the capillary drag of porous substrate. The cause of weight decrease with time in aqueous solution after 300 s was attributed to the defect of film by sagging and electrolytic reaction. The electrolyte film which prepared in alcohol solution with good wetting for substrate had better homogeneous and dense microstructure than one in aqueous solution with high surface tension.

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SOLAR MICROWAVE BURSTS AND ELECTRON KINETICS

  • LEE JEONGWOO;BONG SU-CHAN;YUN HONG SIK
    • Journal of The Korean Astronomical Society
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    • v.36 no.spc1
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    • pp.63-73
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    • 2003
  • Solar flares present a number of radiative characteristics indicative of kinetic processes of high energy particles. Proper understanding of the kinetic processes, however, relies on how well we can separate the acceleration from transport characteristics. In this paper, we discuss microwave and hard X-ray bursts as a powerful tool in investigating the acceleration and transport of high energy electrons. After a brief review of the studies devoted to the kinetic process of solar flare particles, we cast them into a simple formulation which allows us to handle the injection, trap, and precipitation of flare electrons self-consistently. The formulation is then taken as a basis for interpreting and analyzing a set of impulsive and gradual bursts occurred on 2001 April 6 observed with the Owens Valley Solar Array, and HXT/WBS onboard Yohkoh satellite. We quantify the acceleration, trap, and precipitation processes during each burst in terms of relevant time scales, and also determine ambient density and magnetic field. Our result suggests that it should be the acceleration property, in particular, electron pitch angle distribution, rather than the trap condition, that is mainly responsible for the distinctive properties of the impulsive and gradual flares.

Property Evaluation of HVOF Sprayed Multi-walled Carbon Nanotube Aluminum Composite Coatings (고속 화염 용사를 통하여 형성된 다중벽 탄소 나노튜브 알루미늄 복합소재 코팅의 특성 평가)

  • Kang, Ki-Cheol;Park, Hyung-Kwon;Lee, Chang-Hee
    • Journal of the Korean institute of surface engineering
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    • v.45 no.1
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    • pp.1-7
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    • 2012
  • Multi-walled carbon nanotube (MWCNT) aluminum composite powders were deposited to form coatings using a high velocity oxygen fuel (HVOF) spraying process. High thermal energy and contact with atmospheric oxygen were supplied as the MWCNT aluminum composite particles were exposed to a gas flow field at high temperature (${\sim}3.0{\times}10^3$ K) during HVOF spraying. As a result, the particles underwent full or partial melting and rapid solidification due to the high thermal energy, and the exposure to oxygen induced the interfacial reaction of MWCNTs within the particle. The electrical and mechanical properties of MWCNT aluminum composite coatings were evaluated based on microstructure analysis. Electrical resistivity, elastic modulus, and micro-hardness, of the MWCNT aluminum composite coatings were higher than those of pure aluminum coating. The contribution of MWCNTs to the aluminum matrix can be attributed to their high electrical conductivity, dispersion hardening and anchoring effects. The relationship among the properties and the interaction of the MWCNTs with the aluminum matrix is discussed.

Kinetic Measurement of the Step Size of DNA Unwinding by Bacteriophage T7 DNA Helicase gp4 (T7 박테리오파지 gp4 DNA helicase에 의한 DNA unwinding에서 step size의 반응속도론적 측정)

  • Kim, Dong-Eun
    • Journal of Life Science
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    • v.14 no.1
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    • pp.131-140
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    • 2004
  • T7 bacteriophage gp4 is the replicative DNA helicase that unwinds double-stranded DNA by utilizing dTTP hydrolysis energy. The quaternary structure of the active form of T7 helicase is a hexameric ring with a central channel. Single-stranded DNA passes through the central channel of the hexameric ring as the helicase translocates $5'\rightarrow3'$ along the single-stranded DNA. The DNA unwinding was measured by rapid kinetic methods and showed a lag before the single-stranded DNA started to accumulate exponentially. This behavior was analyzed by a kinetic stepping model for the unwinding process. The observed lag phase increased as predicted by the model with increasing double-stranded DNA length. Trap DNA added in the reaction had no effect on the amplitudes of double-stranded DNA unwound, indicating that the $\tau7$ helicase is a highly processive helicase. Global fitting of the kinetic data to the stepping model provided a kinetic step size of 10-11 bp/step with a rate of $3.7 s^{-1}$ per step. Both the mechanism of DNA unwinding and dTTP hydrolysis and the coupling between the two are unaffected by temperature from $4∼37^{\circ}C$. Thus, the kinetic stepping for dsDNA unwinding is an inherent property of tile replicative DNA helicase.

Study on the Thermal Property and Aging Prediction for Pressable Plastic Bonded Explosives through ARC(Heat-wait-search method) & Isothermal Conditions (ARC(Heat-wait-search method)와 Isothermal 조건을 이용한 압축형 복합화약의 열적 특성 및 노화 예측 연구)

  • Lee, Sojung;Kim, Seunghee;Kwon, Kuktae;Jeon, Yeongjin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.4
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    • pp.55-60
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    • 2018
  • The thermal property is one of the most important characteristics in the field of energetic materials. Because energy materials release decomposition heat, differential scanning calorimetry (DSC) is frequently used for thermal analysis. However, thermodynamic events, such as melting can interfere with DSC kinetic analysis. In this study, we use isothermal mode for DSC measurement to avoid thermodynamic issues. We also merge accelerating rate calorimetry(ARC) data with DSC data to obtain a robust prediction results for small scale samples and for large scale samples as well. For the thermal property prediction, advanced kinetics and technology solutions(AKTS) programs are used.

Analysis of Kinetic Parameter Effects on Printing Property in Micro-Contact Printing of Ag Ink (Ag 잉크의 미세접촉인쇄에 있어서 동역학적 파라미터가 인쇄특성에 미치는 영향 분석)

  • Park, Sung-Ryool;Song, Chung-Kun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.2
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    • pp.7-14
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    • 2010
  • This paper describes the effects of kinetic parameters such as attaching speed, attaching time, and dettaching speed on printing property of electrodes which were fabricated by micro-contact printing with Ag ink. In inking process the attaching speed was preferable to be less than 1 mm/s, attaching time as short as possible, and detaching speed larger than 1000 mm/s in order to obtain the transfer ratio of ink larger than 98%. Meanwhile in printing process the parameters were totally opposite to the results of inking process; attaching speed larger than 100 mm/s, attaching time larger than 30 sec, and detaching speed less than 1 mm/s for the best results. With the parameters we could obtain the micro-contact printed electrodes with the minimum line width of $30\;{\mu}m$, thickness of 300~500 nm, roughness less than 50 nm, and resistivity of about $15{\sim}16{\mu\Omega\cdot}cm$.