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Organic Rankine Cycle (ORC) is a promising technology for converting low or medium temperature heat into power. In order to improve the thermodynamic efficiency of ORC systems, adding a regenerator to the system has been widely discussed. However, this needs additional pipes and devices and they will produce additional pressure drop. Considering both the contributions of the regenerator and the power losses caused by additional pressure drop, a theoretical criterion for evaluating the thermodynamic effectiveness of adding a regenerator was proposed by means of mathematic and thermodynamic equations. The core of the criterion is a new concept named Critical Pressure Drop produced by the Regenerator (CPDR). A negative value of CPDR indicates that adding a regenerator will not contribute to the thermodynamic efficiency of ORC systems in any case. An effective regenerator needs a positive value of CPDR, and requires that the value of additional pressure drop produced by introducing the regenerator should be smaller than CPDR. The influences of evaporation temperature, condensation temperature, expander efficiency, regenerator effectiveness and working fluids on CPDR were also examined. It was found that lower evaporation temperature or using working fluids with higher critical temperature tends to reduce the value of CPDR.

Today, hydrogels opened new windows to the high-tech due to their amazing features. Thus, we applied hydrogel nanocomposite (HNC) made of tragacanth gum (a kind of polysaccharide) and CaCO3 nanoparticles to remove methylene blue dye (MBD) from the water solution. We used nonlinear and linear isotherms and kinetics as well as thermodynamics to uncover the adsorption mechanism. The results showed that the hydrogel could remove 80% of MBD. Besides, the linear form of the pseudo-second-order kinetic model fits well with the results, showing chemical interactions. We found that this process follows both Sips and Redlich-Peterson models by applying nonlinear and linear isotherm models. The maximum adsorption capacities from nonlinear and linear Sips were 1401 and 2145 mg/g, respectively. Based on the thermodynamic equations, the adsorption of MBD onto HNC was physiochemical and exothermic. According to the phenomenological calculations, diffusion from the bulk (or film diffusion, Df = 1.2 × 10−8 cm2/s) is the primary mechanism.

This study aims at investigating the thermal decomposition process (pyrolysis) of tea leaf brewing waste (TLBW) and its main component (hemicellulose, cellulose) under non-isothermal conditions and these pyrolysis process kinetic/thermodynamic parameters. Hemicellulose (TLBW-H) and cellulose (TLBW-C) were isolated from the TLBW with delignification process. The isolation effectiveness was discussed and interpreted according to structural analysis (FTIR) results. The fuel analysis (proximate and ultimate), chemical analysis, and structural analysis (FTIR) of the tea leaf brewing waste and its main component were carried out. The thermal analysis (TGA and DTG) of TLBW, TLBW-H, and TLBW-C was investigated under a nitrogen gas atmosphere of 10 ml/min in the temperature range of 25–900 °C. Kinetic and thermodynamic parameters were calculated using Coast–Redfern (CR) model and main thermodynamic equations. A fourteen solid-phase theoretical degradation reaction model was then applied to evaluate the TGA results of the samples. Active pyrolysis started after 210 °C and ended at 527 °C for TLBW-H, 538 °C for TLBW-C, and 602 °C for the TLBW. For the total decomposition steps, the best model equation representing the degradation was found to be the chemical kinetic equation F(3) for all of the samples. Using the model equation that best represents the degradation, the activation energies and ln (A min-1) calculated from the thermal decomposition kinetics of raw tea brewing waste, hemicellulose and cellulose were determined as 46.71-14.42-23.84 kJ/mol and 7.67-13.41-11.92, respectively. As a result, it is predicted that the kinetic and thermodynamic parameters calculated in this study will be useful in terms of the pyrolysis process of TLBW and its main component and the design of pyrolysis reactors.

We establish a nonequilibrium dynamic and thermodynamic formalism in the landscape-flux framework for open Hamiltonian systems in contact with multiple heat baths governed by stochastic dynamics. To systematically characterize nonequilibrium steady states, the nonequilibrium trinity construct is developed, which consists of detailed balance breaking, nonequilibrium potential landscape, and irreversible probability flux. We demonstrate that the temperature difference of the heat baths is the physical origin of detailed balance breaking, which generates the nonequilibrium potential landscape characterizing the nonequilibrium statistics and creates the irreversible probability flux signifying time irreversibility, with the latter two aspects closely connected. It is shown that the stochastic dynamics of the system can be formulated in the landscape-flux form, where the reversible force drives the conservative Hamiltonian dynamics, the irreversible force consisting of a landscape gradient force and an irreversible flux force drives the dissipative dynamics, and the stochastic force adds random fluctuations to the dynamics. The possible connection of the nonequilibrium trinity construct to nonequilibrium phase transitions is also suggested. A set of nonequilibrium thermodynamic equations, applicable to both nonequilibrium steady states and transient relaxation processes, is constructed. We find that an additional thermodynamic quantity, named the mixing entropy production rate, enters the nonequilibrium thermodynamic equations. It arises from the interplay between detailed balance breaking and transient relaxation, and it also relies on the conservative dynamics. At the nonequilibrium steady state, the heat flow, entropy flow, and entropy production are demonstrated to be thermodynamic manifestations of the nonequilibrium trinity construct. The general nonequilibrium formalism is applied to a class of solvable systems consisting of coupled harmonic oscillators. A more specific example of two harmonic oscillators coupled to two heat baths is worked out in detail. The example may facilitate connection with experiments.

In this paper, a modified thermodynamic equation to predict interfacial tension (IFT) at oil/water interfaces with the presence of ionic surfactants and salt is considered. The surfactant activity coefficient is optimized based on the Extended UNIQUAC model according to the experimental results and is used in the modified model. In this study, the effect of salt with the presence of surfactants such as DTAB, M12 L12, SDBS and PFSA in the water/oil system has been considered to investigate the interfacial tension. According to the results of this study, the proposed equation can present a reasonable description of oil/water IFT measurements in the presence of cationic or anionic surfactant solutions and in a range of added salt.

The temperature of plasma jet is difficult to be measured directly because of its high temperature. The heat flux is often used to measure the thermodynamic properties of plasma jet and high temperature flow field. In this paper, two methods of heat flux calculation using slug calorimeter in plasma jet flow field are analyzed. One calculation method is based on one dimensional thermodynamic equation, ignoring the heat loss in the measurement process, called the noloss calculation equation; the other calculation method is to subtract the heat loss from the noloss method. This paper uses numerical simulation and experimental methods to verify the accuracy of the two heat flux calculation equations. The heat flux value is calculated according to the measured data, and the temperature curve is calculated in reverse from the calculated heat flux value. Finally, the calculated temperature curve is compared with the measured temperature curve. The temperature curve with loss heat flux is more consistent with the measured temperature curve. The loss calculation equation can obtain a more accurate heat flux value than the noloss calculation equation, and the error between the two is within 10%. The loss equation is calculated accurately, but it is difficult to give real-time results. There is an error in the noloss equation, but the calculation is simple and gives real-time results.

The main objective of this research is to formulate a novel mathematical model. For modeling the emission of pollutants, the physical principles are captured and simple hypotheses are postulated by the mathematical expressions derived from the stability equations of the mass. The results show the rate of greenhouse gas emissions increases by about 26% when the water flow rate reaches from 1.1 to 1.92 m/s. Also, the obtained data from the model show a very good agreement with the experimental data. Also, the results of this study show the amount of greenhouse gas emissions increases by approximately 2.46% with increasing ambient temperature from 21.4 to 9.43 °C. Finally, the results of this study show it is possible to estimate the degree of gas solubility in water flow with equations of mass transfer and thermodynamics.

The aim of this paper is to construct the thermodynamics of open quantum systems of elementary Bose-gas particles in the framework of nonextensive Tsallis statistics based on modified quantum entropy, which depends on the real deformation parameter $$q.$$ We obtain generalized expressions for the thermodynamic potential, internal energy, free energy, specific heat, and pressure, as well as the basic thermodynamic equations. Modified equilibrium Bose–Einstein distributions for massive particles and generalized Planck, Rayleigh–Jeans, and Wien laws for photons that can be applied to various physical problems, in particular, to the description of cosmic blackbody radiation, are discussed. The initial basis for such a consideration of a photon gas is the assumption that the photon distribution of the cosmic background radiation (in thermal equilibrium) may differ from the classical Planck distribution due to the influence of long-range gravitational effects at large distances. This influence is probably a reflection of the fact that in remote time matter and light were strongly interconnected. The generalized thermodynamics of a photon gas can be used, in particular, as a theoretical justification for experimental studies of blackbody radiation inside various astrophysical objects.

In the present study, 13 aqueous solutions are considered to predict osmotic coefficients of chloride and sulfate aqueous electrolyte systems. For this study (in order to predict osmotic coefficients) the Extended UNIQUAC equation was considered, for AClx=1,2: A = Li, H, Na, K, NH4,Cs, Mg, Ca, Ba (aq) and Bj=1,2SO4: B = Li, Na, K, NH4 (aq) systems. Based on the optimized thermodynamic equation, the effect of concentration and ionic strength on the osmotic coefficient of chloride and sulfate solutions is investigated. According to the results, the osmotic coefficients of the studied systems depend on the ionic strength. For the electrolytic system, the temperature in this study is 298.15 K and pressure is 1 bar. Also, the charge number of cation to anion in this study is 2: 1, 1: 2 and 1: 1.

Numerous experimental data are available on contact angles. However, the majority of them concern sessile droplets, although bubbles are more interesting from the point of view of colloid science, because a sessile bubble is distinguished by the existence of an equilibrium thin liquid film at a gas–solid interface. This paper presents the totality of modern thermodynamic equations necessary for describing the contact angle of a bubble of an arbitrary size. However, in view of their complexity, specific relationships are derived and analyzed for small although macroscopic bubbles. The dependences of a bubble contact angle on the temperature, pressure in a liquid, composition of a liquid phase, and roughness of a solid surface are considered. In the case of a pure liquid, when a gaseous phase consists of its vapor, the obtained relations are of significance for the cavitation theory. The study as a whole has a framework character, and so only the general basic results are presented. Their detailing is possible in combination with experimental data.

In this article, thermal buckling and frequency analysis of a size-dependent laminated composite cylindrical nanoshell in thermal environment using nonlocal strain–stress gradient theory are presented. The thermodynamic equations of the laminated cylindrical nanoshell are based on first-order shear deformation theory, and generalized differential quadrature element method is implemented to solve these equations and obtain natural frequency and critical temperature of the presented model. The results show that by considering C–F boundary conditions and every even layers’ number, in lower value of length scale parameter, by increasing the length scale parameter, the frequency of the structure decreases but in higher value of length scale parameter this matter is inverse. Finally, influences of temperature difference, ply angle, length scale and nonlocal parameters on the critical temperature and frequency of the laminated composite nanostructure are investigated.

This study presents the frequency analysis of a size-dependent laminated polymer composite microtube using a nonlocal strain-stress gradient (NSG) model. By applying energy methods (known as Hamilton’s principle), the motion equations of the laminated micro tube composites are developed. The thermodynamic equations of the laminated microtube are based on first-order shear deformation theory (FSDT), and a generalized differential quadrature method (GDQM) is employed to find the model for the natural frequencies. The results show that by considering C-F boundary conditions (BCs) and every even layers’ number in lower value of length scale parameter, the frequency of the structure drops by soaring this parameter. However, this matter is inverse in its higher value. Eventually, the ply angle’s influences, nonlocality as well as length scale element on the vibration of the laminated composite microstructure are investigated.

The article discusses the thermal processes occurring in a biogas plant in which the mixing device and the heating element are combined into one node, which allows to heat and maintain a given temperature regime more evenly due to the rotation of the heat exchanger and heat transfer to the biomass throughout the entire bioreactor. Required to operate the unit in a thermophilic mode, after its withdrawal to the working state, the heat output is determined by the heat loss of the plant itself and flow with increasing litter temperature to the temperature of the thermophilic mode, which can be described by thermodynamic equations. As a result of theoretical studies, factors have been identified that allow determining the distribution of biomass temperature over the entire volume of the digester. Studies were conducted to obtain data on the impact of the main parameters (design, kinematic and geometric) of a biogas plant and a heat exchanger-agitator on the quality indicators of its work, as well as the thermal processes occurring in it. The theoretical temperature homogeneity of the mixed medium is achieved by combining the heat exchanger and the mixing device into one node, the design and technological parameters of which characterize the intensity of the forced movement of fermented waste, changing the value of thermal conductivity, and finding the temperature field is the main task of the analytical theory of thermal conductivity applicable to the processes occurring in the bioreactor installation.

Equilibrium hydrogen pressures over hydrogenated vanadium, i.e., crystalline VHx with 0 ≤ x ≤ 2 , are estimated based on first-principles calculations to assess the suitability of V-based alloys for use as hydrogen storage materials. For intermediate H contents (x = 0.5 and 1) corresponding to partial site occupancies, a multistep process was used to determine the ground-state structures. First, a large number of configurations with H on tetrahedral (T) or octahedral (O) sites in bcc–type lattices were ranked in terms of energetical stability sans vibrational contributions. Next, phonon calculations were carried out for the lowest-energy structures identified in the first step and zero-point energies added to the electronic energies. Hydrogen pressures for V-VH0.5 and VH-VH2 equilibria were then calculated using these ground-state free energies and thermodynamic equations. Calculation of vibrational energies was simplified by identifying the linear relationship between H content and zero-point energy, which depends only on the type of sites occupied by H atoms. Whereas H atoms preferentially occupy T sites when vibrational terms are ignored, their inclusion leads to H atoms preferentially occupying O sites in both VH0.5 and VH at 0 K. Inclusion of vibrational energy also leads to a better match with reported experimental hydrogen pressures highlighting its importance when assessing the stabilities of different H distributions in metal lattices. The method outlined consists of a more exhaustive configurational search than has been considered previously, and should be useful for systematic investigation of a wide variety of V-based alloys.

International audience; Aluminosilicate glasses and melts are of paramount importance for geo- and materials sciences. They include most magmas, and are used to produce a wide variety of everyday materials, from windows to smartphone displays. Despite this importance, no general model exists with which to predict the atomic structure, thermodynamic and viscous properties of aluminosilicate melts. To address this, we introduce a deep learning framework, ‘i-Melt’, which combines a deep artificial neural network with thermodynamic equations. It is trained to predict 18 different latent and observed properties of melts and glasses in the K2O-Na2O-Al2O3-SiO2 system, including configurational entropy, viscosity, optical refractive index, density, and Raman signals. Viscosity can be predicted in the 100-1015 log10 Pa·s range using five different theoretical frameworks (Adam-Gibbs, Free Volume, MYEGA, VFT, Avramov-Milchev), with a precision equal to, or better than, 0.4 log10 Pa·s on unseen data. Density and optical refractive index (through the Sellmeier equation) can be predicted with errors equal or lower than 0.02 and 0.006, respectively. Raman spectra for K2O-Na2O-Al2O3-SiO2 glasses are also predicted, with a relatively high mean error of ∼25 % due to the limited data set available for training. Latent variables can also be predicted with good precisions. For example, the glass transition temperature, Tg, can be predicted to within 19 K, while the melt configurational entropy at the glass transition, Sconf(Tg), can be predicted to within 0.8 J mol-1 K-1.Applied to rhyolite compositions, i-Melt shows that the rheological threshold separating explosive and effusive eruptions correlates with an increase in the fraction of non-bridging oxygens in rhyolite melts as their alkali/Al ratio becomes larger than 1. Exploring further the effect of the K/(K+Na) ratio on the properties of alkali aluminosilicate melts with compositions varying along a simplified alkali magmatic series trend, we observe that K-rich melts have systematically different structures and higher viscosities compared to Na-rich melts. Combined with the effects of the K/(K+Na) ratio on other parameters, such as the solubility, solution mechanisms and speciation of volatile elements, this could ultimately influence the eruptive dynamics of volcanic systems emitting Na-rich or K-rich alkali magmas.

In this paper we address the problem of modeling and estimating the heat reuse potential of liquid cooled Data Centers (DCs) integrated with local heat distribution system infrastructures and utilities. We provide an abstract mathematical model based on a system-of-systems methodology for representing the heat exchanges between IT equipment and thermal tanks. The behavior of the identified subsystems is modelled mathematically based on thermodynamic equations and physical processes involved in heat exchanges. The models are evaluated on an experimental platform consisting of two liquid-cooled processing units that heat an insulated recipient equipped with temperature sensors, showing a temperature prediction MAPE of 7%. Furthermore, a set of use cases evaluating the heat reuse capability in a residential setup as well as an interior pool heating are presented, showing high potential of heat recycling from IT equipment with liquid cooling systems and the possibility of heating a home with 9 processing units of 210 W power or a pool of size 30 m3 with a set of 100 processing units of 210 W.

A literature review on experimental data for binary mixtures of methane and carbon dioxide with hydrocarbons up to n-hexadecane is presented. Based on these data, the extended corresponding states method, two entropy scaling approaches, and the friction theory are analyzed with respect to their capability of calculating viscosity values with increasing asymmetry of the binary mixture. It is shown that not only the viscosity model but also the underlying thermodynamic equation of state has a significant influence on the result of such calculations. Shortcomings are identified both in the experimental data and in the modeling approaches.

This paper presents the assumptions of a thermodynamic equation of state for polymers according to the Renner model. The experiments involved extruding a biocomposite based on poly(butylene succinate) that was filled with ground wheat bran with its size not exceeding 200 μm. The biocomposite was produced in pellet form with three different contents by weight of wheat bran, i.e., 10%, 30% and 50%. All specimens were examined for their thermodynamic p-v-T characteristics. Taking advantage of the SimFit module of Cadmould 3D-F, experimental results were used to determine the coefficients of thermodynamic equation of state for the tested biocomposite according to the Renner model. The coefficients were then used to calculate transition temperature and to create diagrams illustrating the relationship between pressure, temperature and specific volume for the tested biocomposite. The obtained results can serve as a basis for assessing the suitability of the biocomposite for injection molding, selecting technological parameters of this process, as well as for analyzing shrinkage and defects of injection-molded parts.

Differential geometry is powerful tool to analyze the vapor-liquid critical point on the surface of the thermodynamic equation of state. The existence of usual condition of the critical point $\left( \partial p/\partial V\right) _{T}=0$ requires the isothermal process, but the universality of the critical point is its independence of whatever process is taken, and so we can assume $\left( \partial p/\partial T\right) _{V}=0$. The distinction between the critical point and other points on the surface leads us to further assume that the critical point is geometrically represented by zero Gaussian curvature. A slight extension of the van der Waals equation of state is to letting two parameters $a$ and $b$ in it vary with temperature, which then satisfies both assumptions and reproduces its usual form when the temperature is approximately the critical one., 6 pages. substantially revised

This report addresses the issue of formulating thermodynamic equations of state for multi-component chemical systems that can be consistently applied locally (on a volumetric, molar or specific basis) and so can form the thermodynamic basis of a theory for non-equilibrium transport in non-uniform multi-component reacting fluids. The development of local equations of state, for application in non-uniform multi-component fluid systems, requires the introduction of localised composition variables, such as mole or mass fractions, which are not independent. Robust, unambiguous methods for the mathematical handling of such dependencies are developed, while maintaining close contact with equivalent global thermodynamic relations encountered in uniform systems. While four candidate thermodynamic functions can be the basis of a local equation of state, associated respectively with internal energy, Helmholtz energy, Gibbs energy and enthalpy, the most practically useful is based on the molar Gibbs energy for which the function depends only on intensive state variables (temperature, pressure and composition). For global thermodynamic systems applicable to multi-component uniform systems having n species in equilibrium, equations of state in the form of Gibbs energy functions (homogeneous of order unity with respect to composition variables) are often known at the outset, enabling the development of corresponding local relations required for simulation purposes. Localisation based on the molar Gibbs energy, using the total number of moles of all species N, leads to state variables for composition which are not independent, i.e. the set of n mole fractions {xi}. By comparison, localisation with respect to a fixed total number of moles of all species N* rather than N, leads to the concept of pseudo-mole fractions {xi*}. The set of n variables are independent, but tend to the dependent set of mole fractions {xi} when N* -> N. The molar Gibbs energy function resulting from the latter localisation procedure, expressed in terms of pseudo-mole fractions, can be used to generate chemical potentials, and other thermodynamic molar quantities, by using single partial derivatives in a manner analogous to the well-defined approach used for uniform global systems. Great care is needed when calculating chemical potentials from general molar Gibbs energy functions sourced from literature or experimental data, as it is highly likely that the derived molar Gibbs energy function will lack the homogeneity needed for the use of the single partial derivative formula for chemical potential. A new expression is derived to compute chemical potentials when using a non-homogeneous molar Gibbs energy functions, and a method is presented to construct the homogeneous molar Gibbs energy function of a particular system from any non-homogeneous molar Gibbs energy function. This leads self-consistently to correct general formulae for chemical potentials expressed in terms of intensive state variables, and hence for all partial molar properties for use in local thermodynamic relations. It is observed that an expression for partial pressure of any species of the system has been proposed that applies to non-ideal multi-component systems, and which reduces to the commonly used expression that has been established only for ideal systems. Alternative thermodynamic formulations based on specific rather than molar quantities, and a molar formulation based on n – 1 independent mole fractions, are briefly considered.

The above described procedure for the computation of thermodynamic properties of natural gas was originally published in the Journal Flow Measurement and Instrumentation (Marić, 2005 & 2007). The procedure is derived using fundamental thermodynamic equations (Olander, 2007), DIPPR AIChE (DIPPR® Project 801, 2005) generic ideal heat capacity equations, and AGA-8 (Starling & Savidge, 1992) extended virial-type equations of state. It specifies the calculation of specific heat capacities at a constant pressure cp and at a constant volume cv, the JT coefficient μJT, and the isentropic exponent κ of a natural gas. The thermodynamic properties calculated by this method are in very good agreement with the known experimental data (Ernst et al., 2001). The effects of thermodynamic properties on the accuracy of natural gas flow rate measurements based on differential devices are analyzed. The computationally intensive procedure for the precise compensation of the flow rate error, caused by the JT expansion effects, is derived. In order to make the compensation for the flow rate error executable in real time on low-computing-power digital computers we propose the use of machine learning and the computational intelligence methods. The surrogate models of the flow rate correction procedure are derived by learning the GMDH polynomials (Marić & Ivek, 2010) and by training the MLP artificial neural network. The MLP and the GMDH surrogates significantly reduce the complexity of the compensation procedure while preserving high measurement accuracy, thus enabling the compensation of the flow rate error in real time by low-computing-power microcomputer. The same models can be equally applied for the compensation of the flow rate of natural gas measured by means of orifice plates with corner-, flange- or D and D/2-taps.

Specific heat and entropy are relevant thermodynamic properties, which may be used as macroscopic probes to microscopic properties of materials under ambient conditions and under high applied fields. However, the measurement of specific heat under intense external fields can be a challenging task, as well as to obtain the entropy in the same conditions. Here, we describe a method to obtain high-field specific heat and entropy from measurements of specific heat under ambient conditions and direct temperature change induced by adiabatic field changes. We derive straightforward thermodynamic equations to calculate the specific heat and entropy, and our results agree satisfactorily with experimental data of specific heat under magnetic field, electric field, and pressure.

This paper focuses on a neural network-based structure for predicting significant unmeasurable parameters of a free-piston Stirling oscillator (FPSO). First, the nonlinear dynamic and thermodynamic equations governing a prototype FPSO are extracted. Then, a systematic approach for developing artificial neural network (ANN) is presented to predict the values of five unknown parameters considering nine measurable inputs. The critical unknown parameters include the damping coefficients of power and displacer pistons, the damping coefficient between displacer rod and power piston, and the gas temperatures within the compression and expansion spaces. Subsequently, the proposed ANN is trained and then, the regression analysis as well as the performance evaluation is carried out to validate the obtained ANN model. Furthermore, in order to verify the performance of the proposed ANN model, although limited empirical information is available, the experimental results collected from two prototype FPSOs namely SUTech-SR-1 and B10-B are compared to the ANN outcomes. Moreover, the practical P-V diagrams of the mentioned oscillators, under various realistic operating conditions, are compared to the predictions obtained from the ANN for further verification of the proposed model. Lastly, it is found that the prediction error is less than 4% which affirms the capability of the proposed technique to estimate the unmeasurable parameters of FPSOs.

An equation of state is a thermodynamic equation relating fluid properties which describe the state of matter under a given set of physical conditions. Considering there are some connections between the properties of different fluids, we believe there are some corresponding relations between the critical heat flux (CHF) of different fluids. A corresponding principle was developed to predict the critical heat flux with the experimental data obtained with modeling fluids. A series of scaling criteria were developed on the basis of fluid similarity and molecular thermodynamics, which is totally different from the conventional scaling methods based on experimental data and empirical correlations. The prediction error of this principle is much lower than conventional prediction methods. The average and maximum error of the corresponding principle is about 10%.

Ultrasonic measurements of longitudinal and transverse velocities and of grain density are used to determine a number of thermophysical properties of limestone, dolomite, and siliciclastic rocks of a hydrocarbon reservoir with use of thermoelastic and thermodynamic equations. The equations for the Gruneisen parameter and melting temperature are written in density-independent form suitable for the analysis of the available data. The present study shows that adiabatic compressibility ( κ S ) of the rocks increases (bulk modulus decreases) exponentially. Thermal conductivity ( K l ) and thermal diffusivity ( D ) are determined with an empirical relation. The values of κ S , K l , and D at zero porosity are comparable with the reported values. The Gruneisen parameter and melting temperature decrease nonlinearly but the Debye temperature decreases linearly with increasing porosity. Dolomite stands out as the most massive compared with limestone and siliciclastic rocks.

Recent benchmark test “International Wet Steam Modelling Project” promoted by Joerg Starzmann et al. (Proc. Inst. Mech. Eng. A: J. Power Energy 232, 550–570, 2018) pointed out limitations of current numerical simulations of non-equilibrium condensation of steam. Especially, nucleation and droplet growth models as well as experiments still need some evolution. This paper is focused on the implementation of non-equilibrium condensation model intended for the wider range of pressures covering the typical expansion in steam turbine from high- to low-pressure parts. Due to the wide pressure range, a special attention has been also paid to the implementation of real thermodynamics. The properties of steam are implemented in the form of the spline-based table look-up method (SBTL) approximating the set of IAPWS-95/97 thermodynamics equations for water and steam.

A system of equations is developed to calculate the properties of dissociated steam in the temperature and pressure ranges of 1250–3400 K and 0.01–10.00 MPa. These equations are based on detailed tables for dissociated steam compiled for a mixture of atoms of hydrogen and oxygen, hydroxyl OH, molecules of hydrogen and oxygen, and steam at a reference temperature of 0 K. Since the expansion of dissociated steam in a thermal engine results in its transformation into its common form, the equations for the parameters of dissociated or nondissociated steam uses the same reference temperature, i.e., the water triple point of 273.16 K. A system of equations for the calculation of dissociated-steam properties is derived with the generalized thermodynamic equation, which takes into account the change in the chemical potential and the composition of the mixture during steam dissociation, the Gibbs energy equation, differential thermodynamic equations, and equations for calculation the properties of nondissociated steam. To minimize the deviation of the steam properties calculated by the proposed equations from the table values, the considered temperature and pressure ranges have been divided into three regions. The deviation of the steam properties calculated by the proposed equations from the table values does not exceed 0.05–0.09%. The developed equations can be used in calculations of the processes of cooling of burners and combustion chambers during the combustion of hydrogen–oxygen mixtures, as well as cycles of heat engines that use high-temperature steam as a working fluid at temperatures over 1250 K.

Binary azeotropes, which contain two chemicals with a relative volatility of 1, are very common in the chemical industry. Understanding azeotropes is essential for effectively separating binary azeotropes containing lower alcohols. Experimental techniques and ab initio approaches can produce accurate results; however, these two processes are time consuming and labor intensive. Although thermodynamic equations such as UNIFAC are widely used, experimental values are required, and it is difficult to choose the best groups to represent a complex system. Because of their high efficiency and fast calculation speed, quantitative structure–property relationship (QSPR) tools were used in this work to predict the azeotropic temperatures and compositions of binary azeotropes containing lower alcohols. The QSPR models for 64 binary azeotropes based on centroid approximation and weighted-contribution-factor approximation were established using the genetic function approximation (GFA) procedure in Materials Studio software, and a leave-one-out cross-validation procedure was conducted. External tests of an additional 16 azeotropes were also investigated, and high determination coefficient values were obtained. The best QSPR models were explained in terms of the molecular structure of the azeotropes, and good predictive ability was obtained within acceptable prediction error levels.

The ternary lanthanide Ho(III) complex, [Ho(2,5-DClBA)3(5,5′-DM-2,2′-bipy)]2 (2,5-DClBA=2,5-dichlorobenzoate; 5,5′-DM-2,2′-bipy=5,5′-dimethyl-2,2′-bipyridine) has been successfully synthesized via conventional solution method at room temperature. The complex is characterized by coordination titration analysis, elemental analysis, Infrared spectroscopy and powder X-ray diffraction. In addition, the structure of the complex was characterized by single crystal X-ray diffraction. The results reveal that complex is a binuclear molecular, crystallizing in the triclinic system P ī space group. Each binuclear unit contains two crystallographically independent Ho(III), six 2,5-DClBA and two 5,5′-DM-2,2′-bipy ligands. The binuclear units are assembled into 1D and 2D supramolecular structures by C–H···Cl hydrogen bond and Cl-π interactions. Thermal behavior of the complex was determined by TG-DSC/FTIR techniques. The second thermal decomposition step for complex was calculated by integral iso-conversional nonlinear (NL-INT) method. The value of activation energy E varies slightly with α , indicating that the second decomposition stage of the title complex is single step reaction. Therefore, the improved double equal-double steps method is used to determine the mechanism function of the second thermal decomposition step of the complex. At the same time, the thermodynamic parameters (Δ H ≠ , Δ G ≠ and Δ S ≠ ) and kinetic parameters (activation energy E and the pre-exponential factor A ) of the complex were also calculated. Heat capacity of the complex was measured by a DSC instrument.The experimental molar heat capacity can be fitted to the polynomial equation with the reduced temperature by the means of least square method. Based on the fitted polynomial and thermodynamic equations, the smoothed heat capacity, enthalpy and entropy were calculated.

Liquid CO2 phase transition blasting is a physical blasting method to enhance permeability through liquid CO2 phase transition expansion. To study the propagation criterion of fractures during blasting, the energy of phase transition blasting is evaluated through the thermodynamic equation by studying the action process of the liquid CO2 blasting, thus obtaining the scope of the smash zone and crack zone as well as the propagation criterion of fractures under the effect of high pressure gas. The gas blasting model for a coal body is established based on the SPH algorithm, thus obtaining the criteria for formation of the smash zone and for generatio and propagation of the crack zone. Moreover, the radius of phase transition blasting is surveyed onsite by the peephole method. It is shown that the explosive energy of the MZL-51/2000 phase transition blasting equipment with a release pressure of 270 MPa is 1510 kJ. The coal body is crushed by the high pressure CO2 percussive drilling, forming the smash zone. Meanwhile, fractures are generated around the smash zone. With the expansion and migratio of the gas, the fracture will further grow into a crack zone. The fracture inside the coal body goes through four states: rapid, slow, rapid, and then slow again. According to field surveys, the blasting radius of the MZL-51/2000 equipment with loaded liquid of 1.8 kg is approximately 3 m.

Two new reactor strategies for the continuous poly(ethylene terephthalate) esterification process are proposed for the purpose of intensifying the reaction performance according to different gas-liquid contact modes. Comprehensive mathematical models based on the kinetic and thermodynamic equations are developed to describe and examine two new reactor strategies and four existing industrial strategies. Simulation results of Zimmer esterification process are validated with the plant data. The influences of major operating conditions are investigated, while the performance of each reactor strategy is evaluated. The result shows that reactor type with different gas-liquid contact mode has great influence on mass transfer and reaction performance. The tower reactor strategy with gas-liquid countercurrent operation does well in reaction performance, which can be further improved by means of relocating the gas outlet. Reactor strategy with gas-liquid cocurrent operation balances the reaction performance and the energy consumption. In addition, the reactor strategy with gas-liquid cocurrent (without inert gas venting) gives the best product quality and lowest energy consumption.

Temperature changes in the Arctic lower stratosphere on both short- and long-term time scales are critical for changing the magnitude of ozone losses in the Arctic vortex. In this paper, an approximate month-to-month temperature change equation is constructed and extended to a new form for decade-to-decade changes. Then we provide a verification of these equations and show an example of an application for partitioning between the dynamical and radiative contributions to the Arctic lower-stratospheric temperature decadal changes, as well as the trends, using the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim) data during the period of 1980–99. At 100 hPa, the month-to-month Arctic temperature increment is a small term compared to the dynamical heating and diabatic heating, which are largely canceling terms with maximum magnitudes in November–April and October–March, respectively. However, it is not the case for their decadal changes and the decadal change of the Arctic current-month temperature compared to those of the regressed dynamical heating and radiative heating, where the current-month decadal changes and the corresponding trends are approached except in March and a rough agreement exists between these trends and those reported in other studies. The dynamical plus diabatic heating term and the temperature increment, as well as their decadal changes, are roughly balanced during the annual oscillation. However, some departures exist in both cases because of the large deviations or uncertainties of relevant terms and also probably due to the quasigeostrophic approximation and the eddy heat flux approximation of the dynamical heating, and a restricted condition of the eddy heat flux approximation is given at the end.

Hydrodynamic and thermodynamic equations for the atmosphere are considered in the meteorological and climatic scales in which the inertial forces are negligibly small in comparison with gravity. In this case, the inertia of the horizontal velocity and temperature has an effect. For such a vertically quasi-static flow, an equation for the vertical velocity distribution asymptotically exact in density, temperature, and horizontal velocity is obtained. A closed system of hydro- and thermodynamic equations is presented in which the pressure at each point is determined by the weight of the air column above this point. It is this system of equations that should be used to calculate the climatic and meteorological processes in which the inertia of the horizontal velocity and the inertialess vertical velocity play an essential role.

The solubility of DL-malic acid in methanol, ethanol, propanol, butanol, ethyl acetate and acetonitrile in the temperature range 283–318 K was measured by acid–base titration method. The solubility of DL-malic acid increased with elevating temperature. The solubility data were correlated by the modified Apelblat, Buchowski–Ksiązczak, Van’t Hoff, Wilson, and non-random two-liquid equations. The calculation results showed that these equations provide good prediction with the acceptable ARD values and RMSD values among all the satisfactory fitting results given by each equation. The mixing Gibbs energy, enthalpy and entropy of real solution were derived based on the Wilson equation and the measured solubility data.

One of the best procedures to increase output power and decrease greenhouse gases in power plants is integrated solar combined cycle (ISCC). Two main parts of ISCC which have a great impact on cost and net output power of the cycle are 1) solar field and 2) heat recovery steam generator (HRSG). These two parts are optimized in this paper using the genetic algorithm (GA). As a case study, Components of Damavand power plant have been mathematically modeled using thermodynamic equations. After validation the best procedure to connect the solar field and combined cycle is investigated and two scenarios are considered due to the fact that the case study powerplant has HRSG with two pressure levels. The first scenario is connection of the solar field to the high pressure drum of HRSG and the second scenario is connection of solar field to low pressure drum. After analyzing, the results demonstrate that the second scenario increases the power and reduces the costs. After selection of the best scenario, the design parameters of HRSG and solar field are optimized. The result of GA optimization in HRSG is increase in power by 16.8 MW and 1.1 M$/year decrease in costs. Besides, the result of GA optimization is reducing the cost of solar field construction by 5.1 M$.

Corrosion inhibition performance, thermodynamic parameters and adsorption mechanism of jatropha leaf extract in 2 M HCl solution have been investigated. Inhibition efficiency and corrosion rate were evaluated using gravimetric method, based on ASTM G-31 standards. Activation energy, entropy and enthalpy changes were determined using relevant thermodynamic equations. The mechanism of adsorption was studied using six different adsorption isotherm models. Results obtained show that corrosion rate increased with increase in temperature and decreased with increase in concentration of jatropha leaf extract beyond a maximum dosage. The activation energy of the inhibited process was higher than that of the uninhibited process. The enthalpy and entropy changes obtained were positive and negative, respectively. While the constant of adsorption was positive, Gibb’s free energy change of adsorption was negative with values less than 20KJ/mol. Data obtained fit into Langmuir, Frumkim, El-Awady, Freundlich, Flory Huggins and Tempkin isotherm adsorption models. It was observed that Tempkin model had the best fit and as such was used to evaluate the adsorption constant and Gibb’s free energy change of adsorption. The study found that the adsorption of jatropha leaf extract, on the surface of mild steel, is feasible, spontaneous and follows physical adsorption mechanism.

The objective of this paper is to numerically investigate the thermodynamic effect during bubble collapse near a rigid boundary. A compressible fluid model is introduced to accurately capture the transient process of bubble shapes and temperature, as well as corresponding pressure, and velocity. The accuracy of the numerical model is verified by the experimental data of bubble shapes, and Keller-Kolodner equation as well as its thermodynamic equation. The results show that a bubble near the rigid boundary presents high-speed jet in collapse stage and counter jet in rebound stage, respectively. In the collapse stage, the bubble margin will shrink rapidly and do the positive work on the compressible vapor inside the bubble, then a significant amount of heat will be generated, and finally the generation of high-speed jet drives the low-temperature liquid outside the bubble to occupy the position of high-temperature vapor inside the bubble. In the rebound stage, the counter jet moving away from the rigid boundary takes part of heat away from the sub-bubble, which avoids the external work of the expansion of the sub-bubble and the temperature reduction caused by the dissipation effect of the vortex structure. In addition, the initial standoff has a significant effect on the thermodynamics of bubble oscillation. The temperature keeps increasing with the increase of the initial standoff in the collapse stage, while it shows a downward trend with the increase of the initial standoff in the rebound stage. That's because the high-speed jet and counter jet of bubble gradually disappear when the initial standoff increases, which is the important reason for the opposite evolution trend of temperature in collapse and rebound stage.

Recently, an exchange of views on key fundamental aspects of biological energy coupling and ATP synthesis in the vital process of oxidative phosphorylation appeared in the pages of this journal. The very difficult scientific problems are analyzed and clarified. Errors in the mathematical/thermodynamic equations of a previous analysis have been identified that invalidate previous assertions, and the correct equations are derived. The major differences between the two competing models – localized versus delocalized − for biological energy coupling and transduction are discussed from physical, chemical, and mathematical perspectives. The opposing views are summarized, so that the reader can assess for himself or herself the merits of the two coupling mechanisms. A fresh attempt has been made to go to the root of bioenergetics by calculating the desolvation free energy barrier, ∆Gdesolvation for ion transport across biomembranes. Several constructive suggestions are made that have the power to resolve the basic contradictions and the areas of fundamental conflict, and reach a consensus by catalyzing the progress of future research in this interdisciplinary field.

This paper deals with modeling and multi-criteria optimization of an industrial phosphoric acid process. More specifically, the digestion tank where the phosphate ore is attacked by a concentrated solution of sulfuric acid is considered. A process model is first developed based on mass and heat balances along with Pitzer's thermodynamic equation. It is then identified by means of a set of data made up of experimental measurements carried out and measurements taken from the literature. The resulting model is then used within a multi-criteria optimization problem to determine the optimal operating conditions that minimize the phosphate losses and increase the productivity of the phosphoric acid while meeting the constraints on the temperature and on the excess of sulfuric acid. The optimization problem is solved by means of the epsilon-constraint method and the results are consistent with the current operating conditions of the digestion tank. They also show that the implementation of optimal results on an industrial scale would significantly improve the performance of the tank and under maximum safety conditions.

The paper presents quasy-steady thermodynamics model of ice formation on the aircraft surface of a streamlined body. Numerical methods for solving thermodynamics equations are proposed. Test cases for moist gas flow around the NACA 0012 airfoil and the GLC-305 wing are given. The results are compared with the experimental data to validate the adequacy and the accuracy of models and algorithms. Conclusions about application of algorithm for forecasting the ice accretion on the aircraft elements using proposed approach are given.

Thermodynamics plays a crucial role in food characterization and processing because all the properties can be put in a unique model with the aim to make the material behavior scientifically understandable during any transformation. Since foods are very often multicomponent and multiphase systems, they show rather specific characteristics; therefore, a very robust theoretical approach is required, although many treatises refer to very simple materials, for instance, ideal gases. The theory refers to continuum mechanics, looking to long timescale properties of materials, and is based on state thermodynamics, the main statements of which are discussed in detail in this chapter. The properties of pure systems are specified for different constitutive equations that are largely found when dealing with foods. The phase stability of the pure systems, with reference to different constitutive equations, is also discussed, particularly in the case of vapor-liquid equilibrium. The theory of multicomponent systems is presented in terms of Gibbs theory and chemical potentials, using thermodynamic variables, fugacity, and activity. Since foods are often liquid-like solutions, Gibbs theory is applied to a specific mixture constitutive equation relating food activity to classic process variables such as concentration, temperature, and pressure; in particular, water activity is treated in detail due to its importance in food properties. Finally, the phase stability is illustrated in the case of liquid-vapor, liquid-solid, and liquid-liquid equilibria, by defining the thermodynamic equations governing these states. Reference to food is present throughout the chapter.

Effects of temperature and pressure on the threshold value of stimulated Brillouin scattering (SBS) in seawater were analyzed theoretically and experimentally. Theoretically, the change of threshold value of SBS versus the ocean depth was simulated based on the International Thermodynamic Equation of Seawater-2010 (TEOS-10) and the World Ocean Atlas 2013 (WOA13). Experimentally, an ocean temperature and pressure simulator (OTPS) was designed to measure the threshold value of SBS through simulating the changes of temperature and pressure of seawater in 0∼1000 meters. The theoretical and experimental results exhibit that the threshold value of SBS decreases with the increase of temperature at the same seawater pressure and increases with the increase of pressure at the same seawater temperature. The results imply that the SBS process is more likely to occur in upper seawater of lower-latitude areas. The theoretical and experimental results are helpful for remote sensing in ocean using the SBS LIDAR.

This study answers a primary question concerning how the temperature changes during the flight of a bullet. To answer the question, the authors performed unique research to measure the initial temperatures of bullet surfaces and applied it to four kinds of projectiles in a series of field experiments. The technique determines the temperature changes on metallic objects in flight that reach a velocity of 300 to 900 m/s. Until now, the tests of temperature change available in the literature include virtual points that are adopted to ideal laboratory conditions using classic thermomechanical equations. The authors conducted the first study of its kind, in which is considered four projectiles in field conditions in which a metallic bullet leaves a rifle barrel after a powder deflagration. During this process, heat is partly transferred to the bullet from the initial explosion of the powder and barrel-bullet friction. In this case, the temperature determination of a bullet is complex because it concerns different points on the external surface. Thus, for the first time the authors measured the temperatures at different position on the bullet surface. Moreover, the authors showed that basic thermodynamic equations allow for the credible prediction of such behavior if the initial conditions are identified correctly. This novel identification of the initial conditions of temperature and velocity of flying bullets was not presented anywhere else up to now.