The thermodynamic charge performance of a variable-mass thermodynamic system was investigated by the simulation modeling and experimental analysis. Three sets of experiments were conducted for various charge time and ...The thermodynamic charge performance of a variable-mass thermodynamic system was investigated by the simulation modeling and experimental analysis. Three sets of experiments were conducted for various charge time and charge steam flow under three different control strategies of charge valve. Characteristic performance parameters from the average sub-cooled degree and the charging energy coefficient point of views were also defined to evaluate and predict the charge performance of system combined with the simulation model and experimental data. The results show that the average steam flow reflects the average sub-cooled degree qualitatively, while the charging energy coefficients of 74.6%, 69.9% and 100% relate to the end value of the average sub-cooled degree at 2.1, 2.9 and 0 respectively for the three sets of experiments. The mean and maximum deviations of the results predicted from those by experimental data are smaller than 6.8% and 10.8%, respectively. In conclusion, the decrease of average steam flow can effectively increase the charging energy coefficient in the same charge time condition and therefore improve the thermodynamic charge performance of system. While the increase of the charging energy coefficient by extending the charge time needs the consideration of the operating frequency for steam users.展开更多
Abstract： A joint solution model of variabk：-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated...Abstract： A joint solution model of variabk：-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method （FEM）. The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7~105 W/（m2. K）. When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the： decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase.展开更多
Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging f...Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).展开更多
The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory....The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory.The results indicate that W-Ti alloys except W_(8)Ti_(8) are thermodynamically stable.The modulus and hardness of W-Ti alloys are smaller than those of pure tungsten and gradually decrease with increasing Ti concentration.However,their B/G ratios and Poisson's ratios exceed those of pure tungsten,suggesting that the introduction of Ti decreases the mechanical strength while enhancing the ductility of W-Ti alloys.The thermal expansion coefficients for W-Ti alloys all surpass those of pure tungsten,indicating that the introduction of titanium exacerbates the thermal expansion behavior of W-Ti alloys.Nevertheless,elevated pressure has the capacity to suppress the thermal expansion tendencies in titanium-doped tungsten alloys.This study offers theoretical insights for the design of nuclear materials by exploring the mechanical and thermodynamic properties of W-Ti alloys.展开更多
Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should b...Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.展开更多
Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industr...Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industries.The global production of primary magnesium has reached approximately 1.2 million tons per year,with anticipated diversification in future applications and significant market demand.Nevertheless,approximately 80%of the world’s primary magnesium is still manufactured through the Pidgeon process,grappling with formidable issues including high energy consumption,massive carbon emission,significant resource depletion,and environmental pollution.The implementation of the relative vacuum method shows potential in breaking through technological challenges in the Pidgeon process,facilitating clean,low-carbon continuous magnesium smelting.This paper begins by introducing the principles of the relative vacuum method.Subsequently,it elucidates various innovative process routes,including relative vacuum ferrosilicon reduction,aluminum thermal reduction co-production of spinel,and aluminum thermal reduction co-production of calcium aluminate.Finally,and thermodynamic foundations of the relative vacuum,a quantitative analysis of the material,energy flows,carbon emission,and production cost for several new processes is conducted,comparing and analyzing them against the Pidgeon process.The study findings reveal that,with identical raw materials,the relative vacuum silicon thermal reduction process significantly decreases raw material consumption,energy consumption,and carbon dioxide emissions by 15.86%,30.89%,and 26.27%,respectively,compared to the Pidgeon process.The relative vacuum process,using magnesite as the raw material and aluminum as the reducing agent,has the lowest magnesium-to-feed ratio,at only 3.385.Additionally,its energy consumption and carbon dioxide emissions are the lowest,at 1.817 tce/t Mg and 7.782 t CO_(2)/t Mg,respectively.The energy consumption and carbon emissions of the relative vacuum magnesium smelting process co-producing calcium aluminate(12CaO·7Al_(2)O_(3),3CaO·Al_(2)O_(3),and CaO·Al_(2)O_(3))are highly correlated with the consumption of dolomite in the raw materials.When the reduction temperature is around 1473.15 K,the critical volume fraction of magnesium vapor for different processes varies within the range of 5%–40%.Production cost analysis shows that the relative vacuum primary magnesium smelting process has significant economic benefits.This paper offers essential data support and theoretical guidance for achieving energy efficiency,carbon reduction in magnesium smelting,and the industrial adoption of innovative processes.展开更多
A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge te...A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge ternary alloy was established to analyze the phase formation mechanism of filler metals based on Miedema model,Tanaka model,and Toop equation.This research provided a basis for the composition optimization of filler metals and the analysis of metallurgical reaction process between filler metals and base materials.Results show that Al-Si-Ge alloy is composed of Al-Ge eutectic phase,Al-Si eutectic phase,and primary Si.Ge addition promotes the precipitation of primary Si.Ge is the main melting point depressant element of filler metals.With the increase in Ge content from 10wt%to 40wt%,the solid phase line of filler metals remains unchanged,whereas the liquidus temperature decreases from 567.65°C to 499.96°C.With the increase in Ge content of filler metal,Ge content in eutectic Si phase is increased,the endothermic peak of Al-Si eutectic reaction according to thermogravimetry curve becomes smoother,and Al-Si eutectic temperature is decreased.Ge addition can reduce the free energy of Al-Si alloy system.The lowest point of free energy is located on Al-Ge side.The eutectic Ge phase with the composition similar to pure Ge composition is the most likely to appear in the microstructure of filler metals,whereas the eutectic Si phase with the composition similar to pure Si composition is the least likely to appear.The thermodynamic calculation results are consistent with the experiment results.展开更多
This paper, an addendum to “Dialectical Thermodynamics’ solution to the conceptual imbroglio that is the reversible path”, this journal, 10, 775-799, was written in response to the requests of several readers to pr...This paper, an addendum to “Dialectical Thermodynamics’ solution to the conceptual imbroglio that is the reversible path”, this journal, 10, 775-799, was written in response to the requests of several readers to provide further evidence of the said “imbroglio”. The evidence here presented relates to the incompatibility existing between the total-entropy and the Gibbs energy prescriptions for the reversible path. The previously published proof of the negentropic nature of the transformation of heat into work is here included to validate out conclusions about the Gibbs energy perspective.展开更多
It is shown that time asymmetry is essential for deriving thermodynamic law and arises from the turnover of energy while reducing its information content and driving entropy increase. A dynamically interpreted princip...It is shown that time asymmetry is essential for deriving thermodynamic law and arises from the turnover of energy while reducing its information content and driving entropy increase. A dynamically interpreted principle of least action enables time asymmetry and time flow as a generation of action and redefines useful energy as an information system which implements a form of acting information. This is demonstrated using a basic formula, originally applied for time symmetry/energy conservation considerations, relating time asymmetry (which is conventionally denied but here expressly allowed), to energy behaviour. The results derived then explained that a dynamic energy is driving time asymmetry. It is doing it by decreasing the information content of useful energy, thus generating action and entropy increase, explaining action-time as an information phenomenon. Thermodynamic laws follow directly. The formalism derived readily explains what energy is, why it is conserved (1st law of thermodynamics), why entropy increases (2nd law) and that maximum entropy production within the restraints of the system controls self-organized processes of non-linear irreversible thermodynamics. The general significance of the principle of least action arises from its role of controlling the action generating oriented time of nature. These results contrast with present understanding of time neutrality and clock-time, which are here considered a source of paradoxes, intellectual contradictions and dead-end roads in models explaining nature and the universe.展开更多
We assume exponential corrections to the entropy of 5D charged Ad S black hole solutions,which are derived within the framework of Einstein-Gauss-Bonnet gravity and nonlinear electrodynamics.Additionally,we consider t...We assume exponential corrections to the entropy of 5D charged Ad S black hole solutions,which are derived within the framework of Einstein-Gauss-Bonnet gravity and nonlinear electrodynamics.Additionally,we consider two distinct versions of 5D charged Ad S black holes by setting the parameters q→0 and k→0(where q represents the charge,and k is the non-linear parameter).We investigate these black holes in the extended phase space,where the cosmological constant is interpreted as pressure,demonstrating the first law of black hole thermodynamics.The focus extends to understanding the thermal stability or instability,as well as identifying first and second-order phase transitions.This exploration is carried out through the analysis of various thermodynamic quantities,including heat capacity at constant pressure,Gibbs free energy(GFE),Helmholtz free energy(HFE),and the trace of the Hessian matrix.In order to visualize phase transitions,identify critical points,analyze stability and provide comprehensive analysis,we have made the contour plot of the mentioned thermodynamic quantities and observed that our results are very consistent.These investigations are conducted within the context of exponentially corrected entropies,providing valuable insights into the intricate thermodynamic behavior of these 5D charged Ad S black holes under different parameter limits.展开更多
The thermal effects,spontaneity and proceeding degree of 32 chemical reactions during coal reductive decomposition phosphogypsum(PG)to prepare CaO and SO_(2)are analyzed utilizing thermodynamic theory and method.The i...The thermal effects,spontaneity and proceeding degree of 32 chemical reactions during coal reductive decomposition phosphogypsum(PG)to prepare CaO and SO_(2)are analyzed utilizing thermodynamic theory and method.The ideal reaction temperature for PG decomposition and desulfurization is 1173-1273 K.The 10 key chemical reactions controlling coal reductive decomposition PG have been selected.The heat release of critical exothermic reactions can satisfy the autothermal operation of PG decomposition and desulfurization process.Meanwhile,the spontaneity of oxidation reactions has thermodynamically priority over reduction reactions.But the reaction mechanism shows that the oxidation of CaS by O_(2)is in parallel competition with the reduction of CaSO_(4)by CO and C.Furthermore,clarifying the regulatory mechanisms of PG decomposition temperature and reaction atmosphere(reducibility and oxidation)is beneficial for maximizing the production of CaO and SO_(2).展开更多
Ti-V-Fe-Mn body-centered cubic(BCC)solid solution alloys arouse extensive interests due to the superb hydrogen storage capacity.Understanding phase equilibrium that involves BCC phase is important when designing hydro...Ti-V-Fe-Mn body-centered cubic(BCC)solid solution alloys arouse extensive interests due to the superb hydrogen storage capacity.Understanding phase equilibrium that involves BCC phase is important when designing hydrogen storage materials.However,a reliable thermodynamic description of Ti-V-Fe-Mn system is lacking.To support thermodynamic modeling,ab initio calculations were conducted to determine formation enthalpies of theσand C14 Laves phases.The phase equilibria of Ti-V-Fe alloys at 1273 K and Ti-V-Mn alloys at 1273,1323 and 1373 K were investigated to elucidate the relationship between the BCC and C14 Laves phases.The thermodynamic parameters for the Ti-V-Fe system were revised.The thermodynamic description of the Ti-V-Mn system was established for the first time.Additionally,the V-Mn and V-Fe-Mn systems were thermodynamically reassessed for ensuring consistency in theσphase model.The computed results were comprehensively compared with experimental data,validating that model parameters were reliable.Furthermore,the thermodynamic database for the Ti-V-Fe-Mn system was adopted for predicting phase constitutions of as-cast hydrogen storage alloys,further demonstrating the practical applicability and reliability of the model parameters.展开更多
The effects of pressure on the structural stability,elasticity,electronic properties,and thermodynamic properties of Al,Al_(3)Cu,Al_(2)Cu,Al_(4)Cu_(9),AlCu_(3),and Cu were investigated using first-principles calculati...The effects of pressure on the structural stability,elasticity,electronic properties,and thermodynamic properties of Al,Al_(3)Cu,Al_(2)Cu,Al_(4)Cu_(9),AlCu_(3),and Cu were investigated using first-principles calculations.The experimental results indicate that the calculated equilibrium lattice constant,elastic constant,and elastic modulus agree with both theoretical and experimental data at 0 GPa.The Young's modulus,bulk modulus,and shear modulus increase with increasing pressure.The influence of pressure on mechanical properties is explained from a chemical bond perspective.By employing the quasi-harmonic approximation model of phonon calculation,the temperature and pressure dependence of thermodynamic parameters in the range of 0 to 800 K and 0 to 100 GPa are determined.The findings demonstrate that the thermal capacity and coefficient of thermal expansion increase with increasing temperature and decrease with increasing pressure.This study provides fundamental data and support for experimental investigations and further theoretical research on the properties of aluminum-copper intermetallic compounds.展开更多
Al_(2)O_(3)and MgO serve as the primary gangue components in sintered ores,and they are critical for the formation of CaO-Fe_(2)O_(3)-xAl_(2)O_(3)(wt%,C-F-xA)and CaO-Fe_(2)O_(3)-xM gO(wt%,C-F-xM)systems,respectively.I...Al_(2)O_(3)and MgO serve as the primary gangue components in sintered ores,and they are critical for the formation of CaO-Fe_(2)O_(3)-xAl_(2)O_(3)(wt%,C-F-xA)and CaO-Fe_(2)O_(3)-xM gO(wt%,C-F-xM)systems,respectively.In this study,a nonisothermal crystallization thermodynamics behavior of C-F-xA and C-F-xM systems was examined using differential scanning calorimetry,and a phase identification and microstructure analysis for C-F-xA and C-F-xM systems were carried out by X-ray diffraction and scanning electron microscopy.Results showed that in C-F-2A and C-F-2M systems,the increased cooling rates promoted the precipitation of CaFe_(2)O_(4)(CF)but inhibited the formation of Ca_(2)Fe_(2)O_(5)(C2F).In addition,C-F-2A system exhibited a lower theoretical initial crystallization temperature(1566 K)compared to the C-F system(1578 K).This temperature further decreases to 1554 K and 1528 K in the C-F-4A and C-F-8A systems,respectively.However,in C-F-xM system,the increased MgO content raised the crystallization temperature.This is because that the enhanced precipitation of MF(a spinel phase mainly comprised Fe_(3)O_(4)and MgFe_(2)O_(4))and C2F phases suppressed the CF precipitation reaction.In kinetic calculations,the Ozawa method revealed the apparent activation energies of the C-F-2A and C-F-2M systems.Malek's method revealed that the crystallization process in C-F-2A system initially followed a logarithmic law(lnαor lnα2),later transitioning to a reaction order law((1-α)-1or(1-α)^(-1/2),n=2/3)or the lnα2function of the exponential law.In C-F-2M system,it consistently followed the sequencef(α)=(1-α)^(2)(αis the crystallization conversion rate;n is the Avrami constant;?(α)is the differential equations for the model function of C_(2)F and CF crystallization processes).展开更多
The micellization behavior and thermodynamic properties of cetyltrimethylammonium bromide(CTAB)in single lithium chloride(LiCl),potassium chloride(KCl),magnesium chloride(MgCl_(2))and calcium chloride(CaCl_(2))solutio...The micellization behavior and thermodynamic properties of cetyltrimethylammonium bromide(CTAB)in single lithium chloride(LiCl),potassium chloride(KCl),magnesium chloride(MgCl_(2))and calcium chloride(CaCl_(2))solutions were investigated at 288.15318.15 K.Result showed that the critical micelle concentration(CMC)values of CTAB in all solutions decreased to a minimum value around 298.15 K and then increased with further increasing the temperature.In all cases,the CMC values decreased with increasing salt concentration at each temperature.Additionally,the introduction of any single salt resulted in a reduction of CMC values for CTAB,attributed to the combined effects of counterions and entropy-driven interactions.The observed trend for CMC values was as follows:CMCH_(2)O>CMCKCl>CMCLiCl>CMCCaCl_(2)>CMCMgCl_(2).Furthermore,standard thermodynamic parameters,including standard free energy of micellization(ΔDG_(m)^(0)),standard enthalpy of micellization(ΔDH0m)and standard entropy of micellization(DS0 m),were calculated based on the obtained CMC values.The negative values ofΔDG_(m)^(0)indicated that the formation of CTAB micelles was a spontaneous behavior.The variations inΔDH0m andΔDS_(m)^(0)suggested that micellization was primarily entropy-driven at temperatures between 288.15 and 298.15 K,while it was influenced by both entropy and enthalpy from 298.15 to 318.15 K.Fourier transform infrared spectroscopy(FTIR)and transmission electron microscope(TEM)were employed to further explore the effects of salts on the micellization behavior of CTAB.展开更多
In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodyn...In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodynamics and kinetics of reaction between Si and C,the processes for Si nanocrystals growth and C decoration were coupled at different zones of plasma flame according to its temperature and velocity fields by theoretical modeling,aiming to intentionally suppress the formation of undesirable carbide,and enable adjusting the microstructure of each counterpart separately in transient process.As a result,well-controlled Si/C nanocomposites,including nanospheres and nanowires with core-shell structures,were achieved,and this continuous and in-flight route is also potential for large-scale production.Further investigation on the electrochemical properties highlights the advantage of as proposed strategy to efficiently construct heterostructures with superior performance for various applications.展开更多
The effect of alloying elements on the properties of magnesium(Mg)matrix composites is significant.The distribution of alloy elements between the matrix and the reinforcements plays a pivotal role in the element selec...The effect of alloying elements on the properties of magnesium(Mg)matrix composites is significant.The distribution of alloy elements between the matrix and the reinforcements plays a pivotal role in the element selection and compositional design of Mg-based metal matrix composite.This work used thermodynamics to study the equilibrium distribution coefficients of the 40 elements X(Be,Ca,Zn,Sn,REs,etc.)in the Mg-Ti and Mg-Zr systems at 573 K,773 K and 973 K.In addition,the binary solution enthalpies were evaluated using the Miedema model to predict the bonding tendency of the element X with Mg,Ti and Zr.These research outputs provide valuable data and theoretical reference for Mg-alloy design and optimization.展开更多
The effects of the Rashba spin–orbit interaction and external electric and magnetic fields on the thermodynamic properties of parabolic quantum dots are investigated.An explicit partition function is derived,and ther...The effects of the Rashba spin–orbit interaction and external electric and magnetic fields on the thermodynamic properties of parabolic quantum dots are investigated.An explicit partition function is derived,and thermodynamic quantities,including specific heat,entropy,and magnetic susceptibility,are analyzed.The behavior of Shannon entropy-related thermodynamic quantities is examined under varying magnetic fields and Hamiltonian parameters through numerical analysis.The results reveal a pronounced Schottky anomaly in the heat capacity at lower temperatures.The susceptibility exhibits a progressive enhancement and transitions to higher values with changes in the quantum dot parameters.In the presence of the Rashba spin–orbit interaction,the specific heat increases with temperature,reaches a peak,and then decreases to zero.Additionally,the susceptibility increases with theβparameter for varying Rashba spin–orbit interaction coefficients,and at a fixed temperature,it further increases with the Rashba coefficient.展开更多
This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefie...This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefied natural gas(LNG),methanol,and ammonia.A parametric analysis examines the effect of adjustments to key engine parameters(compression ratio,boost pressure,and air-fuel ratio)on performance.Results show an initial improvement in performance with an increase in compression ratio,which reaches a peak and then declines.Similarly,increases in boost pressure and air-fuel ratio lead to linear performance gains.However,insufficient cooling reduces the amount of fuel burned,which hinders performance.Exergy analysis reveals significant exergy destruction within the engine,which ranges from 69.96%(methanol)to 78.48%(LNG).Notably,the combustion process is the leading cause of exergy loss.Among the fuels tested,methanol exhibits the lowest combustion-related exergy destruction(56.41%),followed by ammonia(62.12%)and LNG(73.77%).These findings suggest that methanol is a promising near-term alternative to LNG for marine fuel applications.展开更多
Gas-phase synthesis of glycolide(GL)from methyl glycolate(MG)is of great significance for producing biodegradable polyglycolic acid.Here,we report a detailed thermodynamics study for the gas-phase synthesis of GL from...Gas-phase synthesis of glycolide(GL)from methyl glycolate(MG)is of great significance for producing biodegradable polyglycolic acid.Here,we report a detailed thermodynamics study for the gas-phase synthesis of GL from MG,which involves complex reaction pathways,by utilizing the Gibbs free energy minimization method.The results indicate that the decompositions of MG and GL and the polymerization of MG are thermodynamically favorable as compared with the target pathway,i.e.,the cyclization of MG.Effects of the reaction conditions including temperature,pressure and feed composition on the formation of GL and linear polymers have also been addressed,which demonstrate that the higher temperature and lower pressure can effectively inhibit the formation of linear methyl ester dimer and improve the selectivity to GL.In addition,the higher N_(2)/MG ratio is beneficial for the formation of GL in the process promoted by catalysts.These thermodynamics results indicate that the process promoted by catalysts would benefit from the kinetics control by high-performance catalysts and the operation at high temperature,low pressure and high N_(2)/MG ratio to enhance the yield of targeted GL.The insights demonstrated here from thermodynamics are valuable for guiding the design of catalysts and/or optimization of reaction conditions for the gas-phase synthesis of GL from MG.展开更多
基金Project(20080431380) supported by the China Postdoctoral Science Foundation
文摘The thermodynamic charge performance of a variable-mass thermodynamic system was investigated by the simulation modeling and experimental analysis. Three sets of experiments were conducted for various charge time and charge steam flow under three different control strategies of charge valve. Characteristic performance parameters from the average sub-cooled degree and the charging energy coefficient point of views were also defined to evaluate and predict the charge performance of system combined with the simulation model and experimental data. The results show that the average steam flow reflects the average sub-cooled degree qualitatively, while the charging energy coefficients of 74.6%, 69.9% and 100% relate to the end value of the average sub-cooled degree at 2.1, 2.9 and 0 respectively for the three sets of experiments. The mean and maximum deviations of the results predicted from those by experimental data are smaller than 6.8% and 10.8%, respectively. In conclusion, the decrease of average steam flow can effectively increase the charging energy coefficient in the same charge time condition and therefore improve the thermodynamic charge performance of system. While the increase of the charging energy coefficient by extending the charge time needs the consideration of the operating frequency for steam users.
基金Project(20080431380) supported by China Postdoctoral Science Foundation
文摘Abstract： A joint solution model of variabk：-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method （FEM）. The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7~105 W/（m2. K）. When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the： decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase.
文摘Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).
基金Funded by National Key R&D Program of China(No.2021YFB3802300)the National Natural Science Foundation of China(No.52171045)the Joint Fund(No.8091B022108)。
文摘The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory.The results indicate that W-Ti alloys except W_(8)Ti_(8) are thermodynamically stable.The modulus and hardness of W-Ti alloys are smaller than those of pure tungsten and gradually decrease with increasing Ti concentration.However,their B/G ratios and Poisson's ratios exceed those of pure tungsten,suggesting that the introduction of Ti decreases the mechanical strength while enhancing the ductility of W-Ti alloys.The thermal expansion coefficients for W-Ti alloys all surpass those of pure tungsten,indicating that the introduction of titanium exacerbates the thermal expansion behavior of W-Ti alloys.Nevertheless,elevated pressure has the capacity to suppress the thermal expansion tendencies in titanium-doped tungsten alloys.This study offers theoretical insights for the design of nuclear materials by exploring the mechanical and thermodynamic properties of W-Ti alloys.
基金supported by the National Natural Science Foundation of China (Nos.42022050 and 42277088)the Guangdong Basic and Applied Basic Research Fund Committee (Nos.2021A1515011248 and 2023A1515012010)the Guangdong Foundation for the Program of Science and Technology Research (No.2020B1212060053).
文摘Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.
基金supported by the China Postdoctoral Science Foundation(No.2023T160088)the Youth Fund of the National Natural Science Foundation of China(No.52304324).
文摘Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industries.The global production of primary magnesium has reached approximately 1.2 million tons per year,with anticipated diversification in future applications and significant market demand.Nevertheless,approximately 80%of the world’s primary magnesium is still manufactured through the Pidgeon process,grappling with formidable issues including high energy consumption,massive carbon emission,significant resource depletion,and environmental pollution.The implementation of the relative vacuum method shows potential in breaking through technological challenges in the Pidgeon process,facilitating clean,low-carbon continuous magnesium smelting.This paper begins by introducing the principles of the relative vacuum method.Subsequently,it elucidates various innovative process routes,including relative vacuum ferrosilicon reduction,aluminum thermal reduction co-production of spinel,and aluminum thermal reduction co-production of calcium aluminate.Finally,and thermodynamic foundations of the relative vacuum,a quantitative analysis of the material,energy flows,carbon emission,and production cost for several new processes is conducted,comparing and analyzing them against the Pidgeon process.The study findings reveal that,with identical raw materials,the relative vacuum silicon thermal reduction process significantly decreases raw material consumption,energy consumption,and carbon dioxide emissions by 15.86%,30.89%,and 26.27%,respectively,compared to the Pidgeon process.The relative vacuum process,using magnesite as the raw material and aluminum as the reducing agent,has the lowest magnesium-to-feed ratio,at only 3.385.Additionally,its energy consumption and carbon dioxide emissions are the lowest,at 1.817 tce/t Mg and 7.782 t CO_(2)/t Mg,respectively.The energy consumption and carbon emissions of the relative vacuum magnesium smelting process co-producing calcium aluminate(12CaO·7Al_(2)O_(3),3CaO·Al_(2)O_(3),and CaO·Al_(2)O_(3))are highly correlated with the consumption of dolomite in the raw materials.When the reduction temperature is around 1473.15 K,the critical volume fraction of magnesium vapor for different processes varies within the range of 5%–40%.Production cost analysis shows that the relative vacuum primary magnesium smelting process has significant economic benefits.This paper offers essential data support and theoretical guidance for achieving energy efficiency,carbon reduction in magnesium smelting,and the industrial adoption of innovative processes.
基金National Natural Science Foundation of China(U22A20191)。
文摘A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge ternary alloy was established to analyze the phase formation mechanism of filler metals based on Miedema model,Tanaka model,and Toop equation.This research provided a basis for the composition optimization of filler metals and the analysis of metallurgical reaction process between filler metals and base materials.Results show that Al-Si-Ge alloy is composed of Al-Ge eutectic phase,Al-Si eutectic phase,and primary Si.Ge addition promotes the precipitation of primary Si.Ge is the main melting point depressant element of filler metals.With the increase in Ge content from 10wt%to 40wt%,the solid phase line of filler metals remains unchanged,whereas the liquidus temperature decreases from 567.65°C to 499.96°C.With the increase in Ge content of filler metal,Ge content in eutectic Si phase is increased,the endothermic peak of Al-Si eutectic reaction according to thermogravimetry curve becomes smoother,and Al-Si eutectic temperature is decreased.Ge addition can reduce the free energy of Al-Si alloy system.The lowest point of free energy is located on Al-Ge side.The eutectic Ge phase with the composition similar to pure Ge composition is the most likely to appear in the microstructure of filler metals,whereas the eutectic Si phase with the composition similar to pure Si composition is the least likely to appear.The thermodynamic calculation results are consistent with the experiment results.
文摘This paper, an addendum to “Dialectical Thermodynamics’ solution to the conceptual imbroglio that is the reversible path”, this journal, 10, 775-799, was written in response to the requests of several readers to provide further evidence of the said “imbroglio”. The evidence here presented relates to the incompatibility existing between the total-entropy and the Gibbs energy prescriptions for the reversible path. The previously published proof of the negentropic nature of the transformation of heat into work is here included to validate out conclusions about the Gibbs energy perspective.
文摘It is shown that time asymmetry is essential for deriving thermodynamic law and arises from the turnover of energy while reducing its information content and driving entropy increase. A dynamically interpreted principle of least action enables time asymmetry and time flow as a generation of action and redefines useful energy as an information system which implements a form of acting information. This is demonstrated using a basic formula, originally applied for time symmetry/energy conservation considerations, relating time asymmetry (which is conventionally denied but here expressly allowed), to energy behaviour. The results derived then explained that a dynamic energy is driving time asymmetry. It is doing it by decreasing the information content of useful energy, thus generating action and entropy increase, explaining action-time as an information phenomenon. Thermodynamic laws follow directly. The formalism derived readily explains what energy is, why it is conserved (1st law of thermodynamics), why entropy increases (2nd law) and that maximum entropy production within the restraints of the system controls self-organized processes of non-linear irreversible thermodynamics. The general significance of the principle of least action arises from its role of controlling the action generating oriented time of nature. These results contrast with present understanding of time neutrality and clock-time, which are here considered a source of paradoxes, intellectual contradictions and dead-end roads in models explaining nature and the universe.
基金the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under Grant No.RGP2/539/45。
文摘We assume exponential corrections to the entropy of 5D charged Ad S black hole solutions,which are derived within the framework of Einstein-Gauss-Bonnet gravity and nonlinear electrodynamics.Additionally,we consider two distinct versions of 5D charged Ad S black holes by setting the parameters q→0 and k→0(where q represents the charge,and k is the non-linear parameter).We investigate these black holes in the extended phase space,where the cosmological constant is interpreted as pressure,demonstrating the first law of black hole thermodynamics.The focus extends to understanding the thermal stability or instability,as well as identifying first and second-order phase transitions.This exploration is carried out through the analysis of various thermodynamic quantities,including heat capacity at constant pressure,Gibbs free energy(GFE),Helmholtz free energy(HFE),and the trace of the Hessian matrix.In order to visualize phase transitions,identify critical points,analyze stability and provide comprehensive analysis,we have made the contour plot of the mentioned thermodynamic quantities and observed that our results are very consistent.These investigations are conducted within the context of exponentially corrected entropies,providing valuable insights into the intricate thermodynamic behavior of these 5D charged Ad S black holes under different parameter limits.
基金financial support by the Phosphogypsum Low-Temperature Decomposition to Produce Calcium-Based Materials and Sulfuric Acid Raw Gas Technology(Horizontal Project)(8503009049)National Natural Science Foundation of China(52376101).
文摘The thermal effects,spontaneity and proceeding degree of 32 chemical reactions during coal reductive decomposition phosphogypsum(PG)to prepare CaO and SO_(2)are analyzed utilizing thermodynamic theory and method.The ideal reaction temperature for PG decomposition and desulfurization is 1173-1273 K.The 10 key chemical reactions controlling coal reductive decomposition PG have been selected.The heat release of critical exothermic reactions can satisfy the autothermal operation of PG decomposition and desulfurization process.Meanwhile,the spontaneity of oxidation reactions has thermodynamically priority over reduction reactions.But the reaction mechanism shows that the oxidation of CaS by O_(2)is in parallel competition with the reduction of CaSO_(4)by CO and C.Furthermore,clarifying the regulatory mechanisms of PG decomposition temperature and reaction atmosphere(reducibility and oxidation)is beneficial for maximizing the production of CaO and SO_(2).
基金supported by the Natural Science Foundation of Shanghai(No.24ZR1425100)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.YESS20210357)+1 种基金the financial supports from the open foundation of Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technology(No.211009-K)State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy and the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200).
文摘Ti-V-Fe-Mn body-centered cubic(BCC)solid solution alloys arouse extensive interests due to the superb hydrogen storage capacity.Understanding phase equilibrium that involves BCC phase is important when designing hydrogen storage materials.However,a reliable thermodynamic description of Ti-V-Fe-Mn system is lacking.To support thermodynamic modeling,ab initio calculations were conducted to determine formation enthalpies of theσand C14 Laves phases.The phase equilibria of Ti-V-Fe alloys at 1273 K and Ti-V-Mn alloys at 1273,1323 and 1373 K were investigated to elucidate the relationship between the BCC and C14 Laves phases.The thermodynamic parameters for the Ti-V-Fe system were revised.The thermodynamic description of the Ti-V-Mn system was established for the first time.Additionally,the V-Mn and V-Fe-Mn systems were thermodynamically reassessed for ensuring consistency in theσphase model.The computed results were comprehensively compared with experimental data,validating that model parameters were reliable.Furthermore,the thermodynamic database for the Ti-V-Fe-Mn system was adopted for predicting phase constitutions of as-cast hydrogen storage alloys,further demonstrating the practical applicability and reliability of the model parameters.
基金Funded by the National Key R&D Program of China(No.2021YFB3802300)the Foundation of National Key Laboratory of Shock Wave and Detonation Physics(No.JCKYS2022212004)the National Natural Science Foundation of China(No.52171045),and the Joint Fund(No.8091B022108)。
文摘The effects of pressure on the structural stability,elasticity,electronic properties,and thermodynamic properties of Al,Al_(3)Cu,Al_(2)Cu,Al_(4)Cu_(9),AlCu_(3),and Cu were investigated using first-principles calculations.The experimental results indicate that the calculated equilibrium lattice constant,elastic constant,and elastic modulus agree with both theoretical and experimental data at 0 GPa.The Young's modulus,bulk modulus,and shear modulus increase with increasing pressure.The influence of pressure on mechanical properties is explained from a chemical bond perspective.By employing the quasi-harmonic approximation model of phonon calculation,the temperature and pressure dependence of thermodynamic parameters in the range of 0 to 800 K and 0 to 100 GPa are determined.The findings demonstrate that the thermal capacity and coefficient of thermal expansion increase with increasing temperature and decrease with increasing pressure.This study provides fundamental data and support for experimental investigations and further theoretical research on the properties of aluminum-copper intermetallic compounds.
基金financially supported by the National Natural Science Foundation of China(Nos.52204331 and 52374315)the Major Industrial Innovation Plan of Anhui Provincial Development and the Reform Commission,China(No.AHZDCYCX-LSDT2023-01)。
文摘Al_(2)O_(3)and MgO serve as the primary gangue components in sintered ores,and they are critical for the formation of CaO-Fe_(2)O_(3)-xAl_(2)O_(3)(wt%,C-F-xA)and CaO-Fe_(2)O_(3)-xM gO(wt%,C-F-xM)systems,respectively.In this study,a nonisothermal crystallization thermodynamics behavior of C-F-xA and C-F-xM systems was examined using differential scanning calorimetry,and a phase identification and microstructure analysis for C-F-xA and C-F-xM systems were carried out by X-ray diffraction and scanning electron microscopy.Results showed that in C-F-2A and C-F-2M systems,the increased cooling rates promoted the precipitation of CaFe_(2)O_(4)(CF)but inhibited the formation of Ca_(2)Fe_(2)O_(5)(C2F).In addition,C-F-2A system exhibited a lower theoretical initial crystallization temperature(1566 K)compared to the C-F system(1578 K).This temperature further decreases to 1554 K and 1528 K in the C-F-4A and C-F-8A systems,respectively.However,in C-F-xM system,the increased MgO content raised the crystallization temperature.This is because that the enhanced precipitation of MF(a spinel phase mainly comprised Fe_(3)O_(4)and MgFe_(2)O_(4))and C2F phases suppressed the CF precipitation reaction.In kinetic calculations,the Ozawa method revealed the apparent activation energies of the C-F-2A and C-F-2M systems.Malek's method revealed that the crystallization process in C-F-2A system initially followed a logarithmic law(lnαor lnα2),later transitioning to a reaction order law((1-α)-1or(1-α)^(-1/2),n=2/3)or the lnα2function of the exponential law.In C-F-2M system,it consistently followed the sequencef(α)=(1-α)^(2)(αis the crystallization conversion rate;n is the Avrami constant;?(α)is the differential equations for the model function of C_(2)F and CF crystallization processes).
基金The support of National Natural Science Foundation of China(22208198 and 22478232)is gratefully acknowledged。
文摘The micellization behavior and thermodynamic properties of cetyltrimethylammonium bromide(CTAB)in single lithium chloride(LiCl),potassium chloride(KCl),magnesium chloride(MgCl_(2))and calcium chloride(CaCl_(2))solutions were investigated at 288.15318.15 K.Result showed that the critical micelle concentration(CMC)values of CTAB in all solutions decreased to a minimum value around 298.15 K and then increased with further increasing the temperature.In all cases,the CMC values decreased with increasing salt concentration at each temperature.Additionally,the introduction of any single salt resulted in a reduction of CMC values for CTAB,attributed to the combined effects of counterions and entropy-driven interactions.The observed trend for CMC values was as follows:CMCH_(2)O>CMCKCl>CMCLiCl>CMCCaCl_(2)>CMCMgCl_(2).Furthermore,standard thermodynamic parameters,including standard free energy of micellization(ΔDG_(m)^(0)),standard enthalpy of micellization(ΔDH0m)and standard entropy of micellization(DS0 m),were calculated based on the obtained CMC values.The negative values ofΔDG_(m)^(0)indicated that the formation of CTAB micelles was a spontaneous behavior.The variations inΔDH0m andΔDS_(m)^(0)suggested that micellization was primarily entropy-driven at temperatures between 288.15 and 298.15 K,while it was influenced by both entropy and enthalpy from 298.15 to 318.15 K.Fourier transform infrared spectroscopy(FTIR)and transmission electron microscope(TEM)were employed to further explore the effects of salts on the micellization behavior of CTAB.
基金financially supported by the National Natural Science Foundation of China(No.52174342)Beijing Natural Sci-ence Foundation(No.2232044)Beijing Municipal Education Commission Research Plan General Project(No.KM202410005009).
文摘In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodynamics and kinetics of reaction between Si and C,the processes for Si nanocrystals growth and C decoration were coupled at different zones of plasma flame according to its temperature and velocity fields by theoretical modeling,aiming to intentionally suppress the formation of undesirable carbide,and enable adjusting the microstructure of each counterpart separately in transient process.As a result,well-controlled Si/C nanocomposites,including nanospheres and nanowires with core-shell structures,were achieved,and this continuous and in-flight route is also potential for large-scale production.Further investigation on the electrochemical properties highlights the advantage of as proposed strategy to efficiently construct heterostructures with superior performance for various applications.
基金the National Natural Science Foundation of China(No.U24A2035&52225101)Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030006).
文摘The effect of alloying elements on the properties of magnesium(Mg)matrix composites is significant.The distribution of alloy elements between the matrix and the reinforcements plays a pivotal role in the element selection and compositional design of Mg-based metal matrix composite.This work used thermodynamics to study the equilibrium distribution coefficients of the 40 elements X(Be,Ca,Zn,Sn,REs,etc.)in the Mg-Ti and Mg-Zr systems at 573 K,773 K and 973 K.In addition,the binary solution enthalpies were evaluated using the Miedema model to predict the bonding tendency of the element X with Mg,Ti and Zr.These research outputs provide valuable data and theoretical reference for Mg-alloy design and optimization.
文摘The effects of the Rashba spin–orbit interaction and external electric and magnetic fields on the thermodynamic properties of parabolic quantum dots are investigated.An explicit partition function is derived,and thermodynamic quantities,including specific heat,entropy,and magnetic susceptibility,are analyzed.The behavior of Shannon entropy-related thermodynamic quantities is examined under varying magnetic fields and Hamiltonian parameters through numerical analysis.The results reveal a pronounced Schottky anomaly in the heat capacity at lower temperatures.The susceptibility exhibits a progressive enhancement and transitions to higher values with changes in the quantum dot parameters.In the presence of the Rashba spin–orbit interaction,the specific heat increases with temperature,reaches a peak,and then decreases to zero.Additionally,the susceptibility increases with theβparameter for varying Rashba spin–orbit interaction coefficients,and at a fixed temperature,it further increases with the Rashba coefficient.
文摘This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefied natural gas(LNG),methanol,and ammonia.A parametric analysis examines the effect of adjustments to key engine parameters(compression ratio,boost pressure,and air-fuel ratio)on performance.Results show an initial improvement in performance with an increase in compression ratio,which reaches a peak and then declines.Similarly,increases in boost pressure and air-fuel ratio lead to linear performance gains.However,insufficient cooling reduces the amount of fuel burned,which hinders performance.Exergy analysis reveals significant exergy destruction within the engine,which ranges from 69.96%(methanol)to 78.48%(LNG).Notably,the combustion process is the leading cause of exergy loss.Among the fuels tested,methanol exhibits the lowest combustion-related exergy destruction(56.41%),followed by ammonia(62.12%)and LNG(73.77%).These findings suggest that methanol is a promising near-term alternative to LNG for marine fuel applications.
基金supported by the National Natural Science Foundation of China(22478106,22178102,and 22332003)Shanghai Rising-Star Program(23QA1401900)+1 种基金Young Elite Scientists Sponsorship Programby CAST(2023QNRC001)the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd(YPML-2023050272).
文摘Gas-phase synthesis of glycolide(GL)from methyl glycolate(MG)is of great significance for producing biodegradable polyglycolic acid.Here,we report a detailed thermodynamics study for the gas-phase synthesis of GL from MG,which involves complex reaction pathways,by utilizing the Gibbs free energy minimization method.The results indicate that the decompositions of MG and GL and the polymerization of MG are thermodynamically favorable as compared with the target pathway,i.e.,the cyclization of MG.Effects of the reaction conditions including temperature,pressure and feed composition on the formation of GL and linear polymers have also been addressed,which demonstrate that the higher temperature and lower pressure can effectively inhibit the formation of linear methyl ester dimer and improve the selectivity to GL.In addition,the higher N_(2)/MG ratio is beneficial for the formation of GL in the process promoted by catalysts.These thermodynamics results indicate that the process promoted by catalysts would benefit from the kinetics control by high-performance catalysts and the operation at high temperature,low pressure and high N_(2)/MG ratio to enhance the yield of targeted GL.The insights demonstrated here from thermodynamics are valuable for guiding the design of catalysts and/or optimization of reaction conditions for the gas-phase synthesis of GL from MG.
