The temperature dependence of thermodynamic quantities, such as heat capacity, entropy and free enthalpy, may be obtained by using well-known equations that relate these quantities to the enthalpy of the molecular system of interest at a range of temperatures. In turn, the enthalpy of a molecular system can be estimated from molecular dynamics simulations of an appropriate model. To demonstrate...

A new Group Contribution Method based on elements and chemical bonds was proposed to predict the enthalpy of evaporation organic compounds at their normal boiling points. prediction model built using 1266 experimental data points, accuracy estimations evaluated 16 The method has only 42 groups, a simple way group splitting, wide range predictions with an average relative error 5.84%. Furthermor...

Enthalpy (fuel mass fraction and/or temperature) fluctuations in the oncoming mixture are known to have important impacts on premixed combustion and in particular on combustion instability. Theoretical modeling has primarily been following an empirical approach. In Part I of the present study, an asymptotically reduced first-principle theory was derived from the reactive Navier-Stokes equations...

It has long been conjectured that spray ejected from the high-wind ocean surface enhances air/sea enthalpy fluxes, but a lack of observational data, particularly at wind speeds exceeding 20 m s−1, has prevented either confirmation or refutation of this hypothesis. The current study has two aims: first, to provide an estimate of surface enthalpy fluxes obtained from dropsonde data and second, to...

simultaneous thermal analysis (sta) method has been applied to study decomposition reactions of ap under a flowing nitrogen atmosphere and static air. results obtained indicate that a phase transformation occurs prior to the decomposition reaction. decomposition takes place exothermally in two stages, first stage of decomposition could be suppressed by the controlled heating programme. addition...

background: heat stress evaluation and timely notification, especially using meteorological data is an important issue attracted attention in recent years. therefore, this study aimed at answering the following research questions: 1) can enthalpy as a common environmental parameter reported by meteorological agencies be applied accurately for evaluation of thermal condition of outdoor settings,...

This paper deals with the hydrodynamic and thermal analysis of a new type of porous heat exchanger (PHE). This system operates based on energy conversion between gas enthalpy and thermal radiation. The proposed PHE has one high temperature (HT) and two heat recovery (HR1 and HR2) sections. In HT section, the enthalpy of flowing high temperature gas flow that is converted to thermal radiation em...