• Title/Summary/Keyword: kinetic studies

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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.

Synthesis of Carbobenzoxy-alanyl-thiaarginine (thialysine) benzyl ester and kinetic Studies with Trypsin

  • 홍남주;장성훈;진동훈
    • Bulletin of the Korean Chemical Society
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    • v.19 no.6
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    • pp.689-695
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    • 1998
  • Carbobenzoxy-alanyl-thiaarginine benzyl ester and carbobenzoxy-alanyl-thialysine benzyl ester were synthesized in solution. Kinetic studies were carried out using three different analytical methods, semi-classical method, progress curve analysis and competitive spectrophotometry. In competitive spectrophotometry, carbobenzoxy-valyl-glycyl-arginyl-p-nitroaniline was used as a detector. Kinetic constants such as $K_m$ and $V_{max}$ measured by competitive spectrophotometry are almost the same as those values measured by semi-classical method. Colorimetric Ellman's assays showed the thio-peptido mimetics to be a suitable substrates for trypsin. Kinetic studies with trypsin gave $K_m$ of 2.33 mM and $k_{cat}$ of $1.50{\times}10^5\;min^{-1}$ for carboxy-alanyl-thiaarginine benzyl ester and $K_m$ of $3.41{\times}10^{-3}\; Mm\; and\; k_{cat}\; of\; 520{\times}102\; min^{-1}$ for carbobenzoxy-alanyl-thialysine benzyl ester, respectively. Kinetic constants $(K_m=2.04{\times}10^{-2}\; mM, K_{cat}=4.42{\times}10^3 \;min^{-1})$ for natural substrate, carbobenzoxy-alanyl-lysine benzyl ester, were also evaluated by competitive spectrophotometry in order to compare the mode of binding on trypsin.

Evaluation of Rainfall Erosivity in Korea using Different Kinetic Energy Equations (강우 운동에너지식에 따른 한국의 강우침식인자 평가)

  • Lee, Joon-Hak;Shin, Ju-Young;Heo, Jun-Haeng
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.3
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    • pp.337-343
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    • 2011
  • A particular empirical equation for rainfall kinetic energy is needed to compute rainfall erosivity, calculated by the annual sum of the product of total rainfall energy and maximum 30-min rainfall intensity. If rainfall kinetic energy equation was different, rainfall erosivity will be produced differently. However, the previous studies in Korea had little concern about rainfall kinetic energy equation and it was not clear which rainfall kinetic energy is suitable for Korea. The purpose of this study is to analyze and evaluate the difference of the rainfall erosivity based on different rainfall kinetic energy equations obtained from previous studies. This study introduced new rainfall erosivity factors based on rainfall kinetic energy equation of Noe and Kwon (1984) that is only regression model developed in Korea. Data of annual rainfall erosivity for 21 weather stations in 1980~1999 were used in this study. The result showed that rainfall erosivity factors by the previous equations had been about 10~20% overestimated than rainfall erosivity by Noe and Kwon (1984)'s equation in Korea.

A Study on the Characteristics of Kinetic Architecture and its Application (키네틱 건축의 특성과 적용가능성에 관한 연구)

  • Moon, Jung-In;Lee, Sang-Ho
    • Korean Institute of Interior Design Journal
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    • v.15 no.2 s.55
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    • pp.21-28
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    • 2006
  • The purpose of this study was to analyze the characteristics of Kinetic Architecture focused on case studies, categorize them and to research the possible applications of Kinetic Architecture. The results are as follow: first, the background of Kinetic Architecture is from the art, machine, nature and ancient architectures. Second, characteristics of Kinetic Architecture are deployability, modularity, lightweight, simplexity and interchangeability of parts. Third, the types of Kinetic Architecture are dynamically self-erecting structures, kinetic components, incremental architecture, mobile and disposable architecture. Finally, today the application cases of Kinetic Architecture are divided into the spital and skin part. The spital part is a temporary space, the multi-purpose spaces, housing, commercial spaces, and the educational spaces. The skin part offers functional(controling environments), artistic images through variation of materials and structural objects in the elevation.

Removal of Heavy Metals by Sawdust Adsorption: Equilibrium and Kinetic Studies

  • Lim, Ji-Hyun;Kang, Hee-Man;Kim, Lee-Hyung;Ko, Seok-Oh
    • Environmental Engineering Research
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    • v.13 no.2
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    • pp.79-84
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    • 2008
  • Adsorption of heavy metals by sawdust was investigated to evaluate the effectiveness of using sawdust to remove heavy metals from aqueous solutions. Kinetic and isotherm studies were carried out by considering the effects of initial concentration and pH. The adsorption isotherms of heavy metals fitted the Langmuir or Freundlich model reasonably well. The adsorption capacity of metal was in the order $Pb^{2+}$ > $Cu^{2+}$ > $Zn^{2+}$. A high concentration of co-existing ions such as $Ca^{2+}$ and $Mg^{2+}$ depressed the adsorption of heavy metal. Adsorption data showed that metal adsorption on sawdust follows a pseudo-second-order reaction. Kinetic studies also indicated that both surface adsorption and intraparticle diffusion were involved in metal adsorption on sawdust. Column studies prove that sawdust could be effective biosorbent for the removal of heavy metals from aqueous phase.

A Comparative Evaluation of Closed and Open Kinetic Exercises in the Management of Chronic Ankle Instability

  • Jung, Namjin
    • Journal of International Academy of Physical Therapy Research
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    • v.11 no.4
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    • pp.2212-2220
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    • 2020
  • Background: Repetitive damage to the ankle joint causes chronic ankle instability, and studies comparing the effects of exercise in open and closed chains as a treatment method are very rare. Objectives: To investigate the effects of open and closed kinetic exercises on muscle activity and dynamic balance of ankle joint in adults with chronic ankle instability. Design: Single-blind randomized controlled trial. Methods: The selected 30 subjects are randomly divided into open kinetic chain exercise experimental group (EGI, n=10), closed kinetic chain exercise experimental group (EGII, n=10), and stretching control group (CG, n=10). Open and closed kinetic exercises lasted 30 minutes three times a week for six weeks and stretching exercises performed four actions for 20 seconds and five sets. The measurement tools using surface electromyography to measure muscle activity in the ankle joint. The dynamic balance of the ankle was evaluated using the Y-Balance test. Results: Following the intervention, closed and open kinetic chain exercise group showed significant difference in tibialis anterior and gastrocnemius muscle activity and dynamic balance (P<.05). However, no significant difference in tibialis anterior and gastrocnemius muscle activity and dynamic balance between closed and open kinetic chain exercise group (P<.05). Conclusion: This study provides evidence that closed and open kinetic chain exercise can be presented as an effective exercise for the muscle activity of ankle muscle and dynamic balance of the subject with chronic ankle instability.