نتایج جستجو برای: activation enthalpy

تعداد نتایج: 433132  

Journal: :ChemEngineering 2023

In Peru, there are more than four thousand plants with medicinal properties, including muña, which helps digestion and improves health. The way to preserve these is drying up. objective of this research was investigate the coefficient diffusion, enthalpy, Gibbs free energy in kinetics muña leaves. Different pretreatments were carried out on samples (without pretreatment, as well treated by imme...

Journal: :Journal of the American Chemical Society 2001
W Sander K Block W Kappert A Kirschfeld S Muthusamy K Schroeder C P Sosa E Kraka D Cremer

Dimesitylketone O-oxide 1b was synthesized by photolysis of dimesityldiazomethane dissolved in an oxygen saturated CCl3F solution at 140 K. Conformation and geometry of 1b were determined by comparing measured NMR chemical shifts with the corresponding chemical shifts calculated at the DFT-IGLO level of theory where it had to be considered that the molecule exists in two enantiomeric forms. Mea...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2004
Sebastian Brauchi Patricio Orio Ramon Latorre

The cold and menthol receptor, TRPM8, also designated CMR1, is a member of the transient receptor potential (TRP) family of excitatory ion channels. TRPM8 is a channel activated by cold temperatures, voltage, and menthol. In this study, we characterize the cold- and voltage-induced activation of TRPM8 channel in an attempt to identify the temperature- and voltage-dependent components involved i...

2017
Liangxu Xie Zhe-Ning Chen Mingjun Yang

The elucidation of entropic contribution to enzyme catalysis has been debated over decades. The recent experimentally measured activation enthalpy and entropy, for chorismate rearrangement reaction in PchB brings up a hotly debated issue whether the chorismate mutase catalyzed reaction is entropy-driven reaction. Extensive configurational sampling combined with quantum mechanics/molecular mecha...

Journal: :Physical chemistry chemical physics : PCCP 2011
Marija Bešter-Rogač Alexander Stoppa Johannes Hunger Glenn Hefter Richard Buchner

Ion association of the ionic liquid [bmim][Cl] in acetonitrile and in water was studied by dielectric spectroscopy for salt concentrations c ≤ 1.3 M at 298.15 K and by measurement of molar electrical conductivities, Λ, of dilute solutions (c ≤ 0.006 M) in the temperature range 273.15 ≲ T/K ≤ 313.15. Whilst acetonitrile solutions of [bmim][Cl] exhibit moderate ion pairing, with an association co...

A. Shokuhfar, H. Arabi, S. Ahmadi, S. Nouri,

Abstract: Guinier-Preston (GP) zone formation and precipitation behavior of T1 (Al2CuLi) phase during the ageingof an Al-Cu-Li-Zr alloy was studied by differential scanning calorimetry (DSC) technique and electrical resistancemeasurement of the samples. Results show that endothermic effects in the thermograms of the alloy between 180°Cand 240°C can be related to the enthalpy of GPzones dissolut...

In the present work, two asymmetric polymer membranes based on polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) with chitin and chitosan (as extractive agents) were synthesized through the phase inversion technique. The mechanisms of oriented process for the facilitated extraction of blue P3R dye across the as-prepared membranes were elucidated through different experiments. Furthe...

Ameneh Alizadeh Ardeshir Shokrollahi, Mehrourang Ghaedi Mojdeh Ranjbar

The objective of this study was to assess the adsorption potential of activated carbon (AC) asan adsorbent for the removal of Murexide (Mu) from aqueous solutions. The influence of variablesparameters including pH, amount of adsorbent, sieve size of adsorbent, temperature and contact timeon Mu removal was studied. Following optimization of variables, the relation between concentrations ofdye re...

Ashwathaiah Ashwini Devarahosahally Veeranna Kirana Thimmasandra Narayan Ramesh

Calcium ions have very strong affinity and binds effectively to alizarin red dye during staining of biomaterials. This promotes us to choose calcium hydroxide as a low cost adsorbent for the removal of alizarin red dye. Various parameters such as pH, concentration, dose of adsorbent, time, and temperature have been investigated. In addition, enthalpy, entropy, free energy and activation energy ...

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