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In the binary Fe-rich Fe-Ni system, martensite start temperatures MS decrease from 500 to 200 K when Ni concentrations increase from 20 to 30 at.%. It is well known that alloys with Ni concentrations below 28.5 at.% exhibit lath martensite (LM) microstructures (athermal transformation, small crystals, accommodation by dislocations). Above this concentration, plate martensite (PM) forms (burst-like transformation, large crystals, accommodation by twins). The present work is based on a combination of (i) ingot metallurgy for the manufacturing of Fe-Ni alloys with varying Ni-concentrations, (ii) thermal analysis to measure phase transformation temperatures with a special focus on MS, and (iii) analytical orientation imaging scanning electron microscopy for a quantitative description of microstructures and crystallographic features. For Ni-concentrations close to 28.5 at.%, the descending MS-curve shows a local maximum, which has been overlooked in prior works. Beyond the local maximum, MS temperatures decrease again and follow the overall trend. The local maximum is associated with the formation of transition martensite (TM) microstructure, which exhibits LM and PM features. TM forms at higher MS temperatures, as it is accommodated by simultaneous twinning and dislocation slip. An adopted version of the Clausius-Clapeyron equation explains the correlation between simultaneous accommodation and increased transformation temperatures. [ABSTRACT FROM AUTHOR]

N2 and O2 adsorption isotherms in chemically modified clinoptilolite-Ca zeolites were experimentally estimated by inverse adsorption chromatography. Natural zeolites (CLINA) were chemically treated with HCl at different concentrations (H1-H4). The adsorption of N2 and O2 on these zeolites was studied in the temperature zone of 398–498 K using gas chromatography. This technique used a thermal-conductivity detector and He as carrier gas, at a rate of 30 mL min−1. The Langmuir and Henry equations were used to describe the experimental results of these gases' adsorption. To evaluate the selectivity of the components of atmospheric air, the chemical activation of the zeolite clinoptilolite-Ca has been carried out. The results are attractive because of the ability to separate the gases these nanomaterials present under dynamic conditions. The structural modifications of the crystalline phases of the studied zeolites were carried out through X-ray diffraction, where the average crystal size was evaluated with the Scherrer equation, finding values of 25.86 nm for CLINA and 15.12 nm for H3 zeolites. The variation of their chemical composition was carried out by energy-dispersive EDS, while the adsorption of N2 carried out their texture properties at 77 K. The selectivity coefficients (α) were evaluated for these gases in pure form and in a mixture (atmospheric air), finding the highest values in zeolites H4 and H3. The interaction energies between these gases with the porous structures of the studied zeolites were evaluated from the evolution of the isosteric enthalpies of adsorption through the Clausius–Clapeyron equation. [ABSTRACT FROM AUTHOR]

Under global warming, the climate in semi-arid inland Eurasia (SAIE) has changed in an opposite manner, thereby seriously impacting the local ecological environment. However, the key influencing factors and physical mechanism remain inconclusive. In this paper, we remodel the precipitation recycling ratio (PRR) model to assess the contributions of moisture from different water vapor sources to local precipitation, analyze the characteristics of the PRR and precipitation in SAIE, and provide possible physical reasons based on the Clausius–Clapeyron equation. It is found that the PRR increased from 1970 to 2017 as the result of linear trend analysis, with obvious seasonality. Moreover, the component of precipitation contributed by locally evaporated moisture (Pl), and that contributed by advected moisture (Pa) as well as the total precipitation (P), increased during the past 48 years. In particular, the Pa, Pl, and P in autumn and winter all increased obviously during the past 20 years from the interdecadal change trend, as well as the PRR (Pl/P), which was opposite to the decrease in the total water vapor input I(Ω) in the horizontal direction. According to the Clausius–Clapeyron equation, one of the causes might be that global warming has accelerated the local water cycle and driven the increase in Pa, and the increase in atmospheric water holding capacity caused by global warming provides the power source. We suggest that the climate's transformation from dry to wet in SAIE can only be temporary since SAIE is an inland area and the adjustment of atmospheric circulation did not lead to the increase in external water vapor. [ABSTRACT FROM AUTHOR]

Four ionic liquids (ILs) based on the bis(trifluoromethanesulfonyl)imide (NTf2) anion were synthesized and characterized concerning their thermal stability, the occurrence of low temperature phase transitions and their volatility. All these physical quantities are highly important for possible applications. Both monocationic and dicationic ILs were considered. All ILs exhibit thermal stability exceeding 350 °C, an extremely high value, due to the presence of the NTf2 anion. Monocationic ILs can undergo crystallization, and they melt at 1 and 38 °C. On the contrary, dicationic ILs containing large positively charged ions display only a glass transition around −40 °C, without any crystallization or melting process; this fact is particularly important in view of the possibly low temperature applications of the dication ILs. The vapor pressure, pv, of the four ILs was measured by isothermal thermogravimetry in the temperature range between 250 and 325 °C; the lowest values of pv were obtained for the two dicationic liquids, suggesting that they are particularly well suited for high temperature applications. The vaporization enthalpy was calculated through the Clausius–Clapeyron equation and was found in the range between ~140 and ~180 kJ/mol depending on the specific IL. [ABSTRACT FROM AUTHOR]

Prediction of adsorption isotherms under different temperatures is significant to reserve estimation of shale gas reservoirs. Based on the Polanyi adsorption potential theory and Langmuir adsorption theory, a method was presented to predict adsorption isotherms at different temperatures. In this method, the relationship between Langmuir pressure and temperature was quantified. By utilizing this method, we predicted adsorption isotherms of Longmaxi shale from 45 °C to 120 °C according to experimental data at 30 °C. Meanwhile, by considering the pressure and temperature gradients, we also predicted the adsorption capacity of Longmaxi shale with geologic depth. Results show that the adsorption data predicted by our method are in accord with experimental data and the error coefficient is less than 5%. In addition, the isosteric heat of adsorption for Longmaxi shale can be calculated by predicted adsorption data based on the Clausius–Clapeyron equation of capillary systems. Therefore, our study illustrates theoretical foundations for the efficient evaluation of adsorbed gas content in shale gas reservoirs at geologic conditions. [ABSTRACT FROM AUTHOR]

Powders based on plant raw materials have low storage stability due to their sorption and thermal properties and generate problems during processing. Therefore, there is a need to find carrier agents to improve their storage life as well as methods to evaluate their properties during storage. Water adsorption isotherms and thermal characteristics of the pumpkin powder with various inulin additions were investigated in order to develop state diagrams. Differential scanning calorimetry (DSC) was used to obtained glass transition lines, freezing curves and maximal-freeze-concentration conditions. The glass transition lines were developed using the Gordon–Taylor model. Freezing data were modeled employing the Clausius–Clapeyron equation and its development–Chen model. The glass transition temperature of anhydrous material (Tgs) and characteristic glass transition temperature of maximum-freeze-concentration (Tg′) increased with growing inulin additions. Sorption isotherms of the powders were determined at 25 °C by the static-gravimetric method and the experimental data was modeled with four different mathematical models. The Peleg model was the most adequate to describe the sorption data of the pumpkin–inulin powders. Guggenheim-Anderson-de Boer (GAB) monolayer capacity decreased with increasing inulin concentration in the sample. [ABSTRACT FROM AUTHOR]

Detection, attribution and projection of changes in tropical cyclone intensity statistics are made difficult from the potentially decreasing overall storm frequency combined with increases in the peak winds of the most intense storms as the climate warms. Multi-decadal simulations of stabilized climate scenarios from a high-resolution tropical cyclone permitting atmospheric general circulation model are used to examine simulated global changes from warmer temperatures, if any, in estimates of tropical cyclone size, accumulated cyclonic energy and power dissipation index. Changes in these metrics are found to be complicated functions of storm categorization and global averages of them are unlikely to easily reveal the impact of climate change on future tropical cyclone intensity statistics. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) is considered one of the most important greenhouse gases in the study of climate change. CO2 adsorption was studied using the gas chromatography technique, while the Freundlich and Langmuir adsorption models were employed for processing isotherm data in the temperature range of 473–573 K. The isosteric heat of adsorption was calculated from the Clausius–Clapeyron equation. Moreover, the thermodynamic properties ΔG, ΔU, and ΔS were evaluated from the adsorption isotherms of Langmuir using the Van’t Hoff Equation. The four soil samples were recollected from San Juan Amecac, Puebla, Mexico, and their morphologies were investigated through X-ray diffraction (XRD) and N2 adsorption at 77 K. The SJA4 soil has a crystalline Kaolinite phase, which is one of its non-metallic raw materials, and N2 isotherms allowed for the determination of pore size distributions and specific surface areas of soil samples. The Barrett–Joyner–Halenda (BJH) distribution of pore diameters was bimodal with peaks at 1.04 and 3.7 nm, respectively. CO2 adsorption showed that the SJA1 soil afforded a higher amount of adsorbed CO2 in the temperature range from 453 to 573 K followed by SJA4 and finally SJA2, classifying this process as exothermic physisorption. [ABSTRACT FROM AUTHOR]

In the present work, the sublimation of crystalline solid 2-(2-nitrovinyl) furan (G-0) in the temperature range of 35 to 60 °C (below the melting point of the drug) was studied using thermogravimetric analysis (TGA). The sublimated product was characterized using Fourier-transformed-infrared spectroscopy (FT-IR) and thin layer chromatography (TLC). The sublimation rate at each temperature was obtained using the slope of the linear regression model and followed apparent zero-order kinetics. The sublimation enthalpy from 35 to 60 °C was obtained from the Eyring equation. The Gückel method was used to estimate the sublimation rate and vapor pressure at 25 °C. Physical mixtures, kneaded and freeze-dried complexes were prepared with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) and analyzed using isothermal TGA at 50 °C. The complexation contributed to reducing the sublimation process. The best results were achieved using freeze-dried complexes with both cyclodextrins. [ABSTRACT FROM AUTHOR]

The theoretical description of water properties continues to be a challenge. Using quantum cluster equilibrium (QCE) theory, we combine state-of-the-art quantum chemistry and statistical thermodynamic methods with the almost historical Clausius–Clapeyron relation to study water self-dissociation and the thermodynamics of vaporization. We pay particular attention to the treatment of internal rotations and their impact on the investigated properties by employing the modified rigid-rotor–harmonic-oscillator (mRRHO) approach. We also study a novel QCE parameter-optimization procedure. Both the ionic product and the vaporization enthalpy yield an astonishing agreement with experimental reference data. A significant influence of the mRRHO approach is observed for cluster populations and, consequently, for the ionic product. Thermodynamic properties are less affected by the treatment of these low-frequency modes. [ABSTRACT FROM AUTHOR]

Electrodeposited antimony can be treated with sulfuration–volatilization technology, which causes antimony to volatilize in the form of antimony sulfide. During this process, gold is enriched in the residue, thereby realizing the value-added use of antimony and the recovery of gold. In this study, the thermodynamic conditions of antimony sulfide were analyzed by the Clausius–Clapeyron equation. Moreover, the volatilization behavior of antimony sulfide and the enrichment law of gold were studied by heat volatilization experiments. The effects of the sulfide temperature and volatilization pressure on the separation efficiency of antimony and gold enrichment were investigated. The results demonstrate that the sulfuration rate was the highest, namely 96.06%, when the molar ratio of sulfur to antimony was 3:1, the sulfur source temperature was 400 °C, the antimony source temperature was 550 °C, and the sulfuration time was 30 min. Antimony sulfide prepared under these conditions was volatilized at 800 °C over 2 h at an evaporation pressure of 0.2 atm, and the volatilization rate was the highest, namely 92.81%. Antimony sulfide with a stibnite structure obtained from the sulfuration–volatilization treatment of electrodeposited antimony meets the ideal stoichiometric ratio of sulfur and antimony in Sb2S3 (3:2), and gold is enriched in the residue. [ABSTRACT FROM AUTHOR]

Experimental and field observations evidence the effects of capillarity in narrow pores on inhibiting the thermodynamic stability of gas hydrates and controlling their saturation. Thus, precise estimates of the gas hydrate global inventory require models that accurately describe gas hydrate stability in sediments. Here, an equilibrium model for hydrate formation in sediments that accounts for capillary inhibition effects is developed and validated against experimental data. Analogous to water freezing in pores, the model assumes that hydrate formation is controlled by the sediment pore size distribution and the balance of capillary forces at the hydrate–liquid interface. To build the formulation, we first derive the Clausius–Clapeyron equation for the thermodynamic equilibrium of methane and water chemical potentials. Then, this equation is combined with the van Genuchten's capillary pressure to relate the thermodynamic properties of the system to the sediment pore size distribution and hydrate saturation. The model examines the influence of the sediment pore size distribution on hydrate saturation through the simulation of hydrate formation in sand, silt, and clays, under equilibrium conditions and without mass transfer limitations. The results show that at pressure–temperature conditions typically found in the seabed, capillary effects in very fine-grained clays can limit the maximum hydrate saturation below 20% of the host sediment porosity. [ABSTRACT FROM AUTHOR]

Using data from the Integrated Global Radiosonde Archive Version 2 (IGRA2) and the Multi Model Ensemble (MME) of four global climate models (GCMs), named CanESM5, IPSL-CM6A-LR, MIROC6, and MRI-ESM2-0, within the framework of phase 6 of the Coupled Model Intercomparison Project (CMIP6), we analyzed the changes in atmospheric total column water vapor (TCWV) over Central Asia in the future (2021–2100) under SSP-RCPs scenarios: SSP1-1.9, SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0, and SSP5-8.5, relative to baseline period (1986–2005). Results showed that the annual mean TCWV from IGRA2 was consistent with the model output from 1979 to 2014 in Central Asia. Besides, the spatial distribution of TCWV in Central Asia during the baseline period was consistent between the models. The regional average value of Central Asia was between 10.8 mm and 12.4 mm, and decreased with elevation. TCWV will increase under different SSP-RCPs from 2021 to 2040, but showed different trends after 2040. It will increase under SSP1-1.9 and SSP1-2.6 scenarios from 2021 to 2050, and decrease after that. It will grow from 2021 to 2055 under SSP4-3.4 scenario, and then stay essentially constant. Under SSP2-4.5 and SSP4-6.0 scenarios, TCWV will rise rapidly during 2021–2065, but the growth will decline from 2065 to 2100. TCWV will continue to increase under SSP3-7.0 and SSP5-8.5 scenarios, and the largest increase is projected under SSP5-8.5 scenario. Change in near-surface temperature (Ts) matched the change in TCWV, but changes in precipitation and evapotranspiration are not significant during 2021–2100. In spite of the large variations in TCWV under different SSP-RCPs, the dominant characteristic in all scenarios shows that a large TCWV increase is demonstrated over areas with small TCWV amounts during the baseline period. On the contrary, increases will be small where the TCWV amounts had been large during the baseline period. The change in TCWV is highly correlated to the increase in Ts in Central Asia. Under SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0, and SSP5-8.5 scenarios, the higher the temperature due to higher radiative forcing, the steeper the regression slope between TCWV and Ts change. It is closest to the theoretical value of the Clausius-Clapeyron equation under SSP3-7.0 and SSP5-8.5 scenarios, but not presented under other scenarios. Spatially, steeper regression slopes during 2021–2100 have been found around the Caspian Sea in the southwest and in the high-elevation areas in the southeast of Central Asia, which is likely related to the abundant local water supply for evaporation. [ABSTRACT FROM AUTHOR]

Record-breaking precipitation events have been frequent in Japan in recent years. To investigate the statistical characteristics of the frequency of record-breaking events, observations can be compared with the values derived from sampling theory with a stationary state. This study counted the number of record-breaking daily and 3-day total precipitation events at 58 rain-gauge stations in Japan between 1901 and 2018. The average number of record-breaking events over the 118-year period was 5.9 for daily total precipitation, which is larger than the theoretical value of 5.4 derived using the assumption that the climate system over the same period was stationary. Sampling theory was used to incorporate the influence of the long-term temperature trend from the Clausius–Clapeyron relation associated with the saturation vapor pressure. In theory, the long-term temperature trend gives a similar number of observed record-breaking events when the long-term temperature trend is approximately 0.5 Kelvin/100 years. [ABSTRACT FROM AUTHOR]

We have proposed a consistent thermodynamic scheme for evaluation of enthalpy changes of hydrate phase transitions based on residual thermodynamics. This entails obtaining every hydrate property such as gas hydrate pressure-temperature equilibrium curves, change in free energy which is the thermodynamic driving force in kinetic theories, and of course, enthalpy changes of hydrate dissociation and formation. Enthalpy change of a hydrate phase transition is a vital property of gas hydrate. However, experimental data in literature lacks vital information required for proper understanding and interpretation, and indirect methods of obtaining this important hydrate property based on the Clapeyron and Clausius-Clapeyron equations also have some limitations. The Clausius-Clapeyron approach for example involves oversimplifications that make results obtained from it to be inconsistent and unreliable. We have used our proposed approach to evaluate consistent enthalpy changes of hydrate phase transitions as a function of temperature and pressure, and hydration number for CH4 and CO2. Several results in the literature of enthalpy changes of hydrate dissociation and formation from experiment, and Clapeyron and Clausius-Clapeyron approaches have been studied which show a considerable disagreement. We also present the implication of these enthalpy changes of hydrate phase transitions to environmentally friendly production of energy from naturally existing CH4 hydrate and simultaneously storing CO2 on a long-term basis as CO2 hydrate. We estimated enthalpy changes of hydrate phase transition for CO2 to be 10–11 kJ/mol of guest molecule greater than that of CH4 within a temperature range of 273–280 K. Therefore, the exothermic heat liberated when a CO2 hydrate is formed is greater or more than the endothermic heat needed for dissociation of the in-situ methane hydrate. [ABSTRACT FROM AUTHOR]