نتایج جستجو برای: standard enthalpy

تعداد نتایج: 522943  

2007
Ali Vatani Mehdi Mehrpooya Farhad Gharagheizi

The standard enthalpy of formation of 1115 compounds from all chemical groups, were predicted using genetic algorithm-based multivariate linear regression (GAMLR). The obtained multivariate linear five descriptors model by GA-MLR has correlation coefficient ( 9830 . 0 2 = R ). All molecular descriptors which have entered in this model are calculated from chemical structure of any molecule. As a...

2014
Babak Mehmandoust Ehsan Sanjari Mostafa Vatani

The heat of vaporization of a pure substance at its normal boiling temperature is a very important property in many chemical processes. In this work, a new empirical method was developed to predict vaporization enthalpy of pure substances. This equation is a function of normal boiling temperature, critical temperature, and critical pressure. The presented model is simple to use and provides an ...

2000
Jorge Marrero Rafiqul Gani

A new method for the estimation of properties of pure organic compounds is presented. Estimation is performed at three levels. The primary level uses contributions from simple groups that allow describing a wide variety of organic compounds while the higher levels involves polyfunctional and structural groups that provide more information about molecular fragments whose description through firs...

Journal: :Molecules 2017
Rudolf Naef William E Acree

The calculation of the standard enthalpies of vaporization, sublimation and solvation of organic molecules is presented using a common computer algorithm on the basis of a group-additivity method. The same algorithm is also shown to enable the calculation of their entropy of fusion as well as the total phase-change entropy of liquid crystals. The present method is based on the complete breakdow...

2017
George Kim S V Meschel Philip Nash Wei Chen

The standard enthalpy of formation of a compound is the energy associated with the reaction to form the compound from its component elements. The standard enthalpy of formation is a fundamental thermodynamic property that determines its phase stability, which can be coupled with other thermodynamic data to calculate phase diagrams. Calorimetry provides the only direct method by which the standa...

حیدری, حمیدرضا, رحیمی فرد, هدی, شکری, زهرا, صحرانورد, ربابه, محمدبیگی, ابولفضل, گلبابایی, فریده,

Introduction: Considering the necessity of evaluating novel thermal indices for different individual and environmental conditions, the aim of this study was validation of a new enthalpy index for evaluation of heat stress in hot and dry climate. Material and Method: In this descriptive analytical 97 city services outdoor workers were randomly selected and evaluated in spring and summer sea...

2015
Etsuro Ito Yusuke Ikemoto Tohru Yoshioka

The activity of thermo-transient receptor potential (TRP) channels is highly dependent on temperature, and thus thermo-TRP reactions have a high temperature coefficient Q 10. In thermodynamics, a high value of Q 10 indicates the existence of a large activation energy (i.e., a large enthalpy) over a short period during the transition process between the closed and open states of the channels. Th...

2014
Angus Yeh Jake Boyce-Bacon Mike O’Sullivan

Production wells on deliverability are often used in modelling geothermal fields, especially for simulations of future scenarios. The mass flow rate is calculated by multiplying the productivity index by mobility and the difference between flowing bottom-hole pressure and the reservoir block pressure. Here three options are considered for calculating the bottom-hole pressure: (i) constant, (ii)...

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