Journal articles: 'Clausius-Clapeyron equation'

1

Velasco, S., F. L. Román, and J. A. White. "On the Clausius–Clapeyron Vapor Pressure Equation." Journal of Chemical Education 86, no. 1 (January 2009): 106. http://dx.doi.org/10.1021/ed086p106.

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2

Kołaczkiewicz, J., and E. Bauer. "Clausius-Clapeyron equation analysis of two-dimensional vaporization." Surface Science Letters 155, no. 2-3 (June 1985): A277. http://dx.doi.org/10.1016/0167-2584(85)91056-4.

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Kołaczkiewicz, J., and E. Bauer. "Clausius-Clapeyron equation analysis of two- dimensional vaporization." Surface Science 155, no. 2-3 (June 1985): 700–714. http://dx.doi.org/10.1016/0039-6028(85)90023-8.

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4

Novak, Igor. "From the Arrhenius to the Clausius?Clapeyron Equation." Chemical Educator 7, no. 6 (December 2002): 347–48. http://dx.doi.org/10.1007/s00897020617a.

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5

Moin, Ph B. "Thermodynamic potentials and Clausius–Clapeyron equation for strained solids." Phase Transitions 86, no. 4 (April 2013): 361–64. http://dx.doi.org/10.1080/01411594.2012.683872.

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6

Joos, P. "The Clausius-Clapeyron Equation in Monolayers: I. Thermodynamic Treatment." Bulletin des Sociétés Chimiques Belges 79, no. 11-12 (September 2, 2010): 645–53. http://dx.doi.org/10.1002/bscb.19700791108.

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Thompson, Jason E., and Andrew S. Paluch. "Revisiting the Clausius/Clapeyron Equation and the Cause of Linearity." Thermo 3, no. 3 (July 17, 2023): 412–23. http://dx.doi.org/10.3390/thermo3030025.

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In general, for an organic compound a plot of the log vapor pressure versus inverse temperature is linear over a wide temperature range. This however can lead to a point of confusion in an undergraduate thermodynamics course. This linear behavior is typically explained using the Clausius/Clapeyron equation. That is, starting with the Clapeyron equation one first assumes (1) that the change in compressibility upon vaporization is approximately 1, or equivalently that the vapor phase may be treated as an ideal gas where the molar volume of the vapor is much greater than that of the liquid, which may be assumed negligible. And second (2), that the enthalpy of vaporization is constant. While the resulting linear behavior is captured, the underlying assumptions are not applicable over the wide range of temperatures of interest. Here we discuss the shortcomings of the conventional explanation of the Clausius/Clapeyron equation. We further demonstrate that a simple solution is to instead assume that the enthalpy of vaporization relative to the change in compressibility upon vaporization is constant. We provide a series of examples and MATLAB code that can be used in an undergraduate thermodynamics course.

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Joos, P. "The Clausius-Clapeyron Equation in Monolayers: II. Some Experimental Evidence." Bulletin des Sociétés Chimiques Belges 79, no. 11-12 (September 2, 2010): 655–63. http://dx.doi.org/10.1002/bscb.19700791109.

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9

Ntsondwa, Sindisiwe, Velaphi Msomi, and Moses Basitere. "Evaluation of the Adsorptive Process on Adsorbent Surfaces as a Function of Pressure in an Isosteric System Compared with Adsorption Isotherm." ChemEngineering 6, no. 4 (July 1, 2022): 52. http://dx.doi.org/10.3390/chemengineering6040052.

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The developing significance of adsorption has brought about a steadily expanding quantity of logical and innovative writing on different adsorbents. This paper intends to propose experimental and computational methods for measuring the strength of adsorbate–solid interactions. It primarily focuses on the use of graphs to measure the effectiveness of an adsorbate’s bonds with the solid adsorbent by determining the isosteric heat. The Clausius–Clapeyron model equation is used to determine the isosteric enthalpy of adsorption from two adsorption isotherms at various but close temperatures, with ΔT of 10 °C. A full computational explanation of the Clausius–Clapeyron model equation for determining ΔHads is provided using experimental data. Logarithmic plots of uptakes vs. p in the low-pressure zone for the Freundlich–Langmuir graph are used to assess and confirm the quality of the crucial underlying isotherms. The isosteric heat was found to be between 13.5 kJ/mol and 16 kJ/mol.

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10

Schleiss, Marc. "How intermittency affects the rate at which rainfall extremes respond to changes in temperature." Earth System Dynamics 9, no. 3 (July 9, 2018): 955–68. http://dx.doi.org/10.5194/esd-9-955-2018.

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Abstract. A detailed analysis of how intermittency (i.e., the alternation of dry and rainy periods) modulates the rate at which sub-daily rainfall extremes depend on temperature is presented. Results show that hourly extremes tend to be predominantly controlled by peak intensity, increasing at a rate of approximately 7 % per degree in agreement with the Clausius–Clapeyron equation. However, a rapid increase in intermittency upward of 20–25 °C is shown to produce local deviations from this theoretical scaling, resulting in lower scaling rates. On the other hand, rapidly decreasing intermittency with temperature between 10 and 20° can result in higher net scaling rates than expected, potentially exceeding Clausius–Clapeyron. In general, the importance of intermittency in controlling the scaling rates of precipitation with temperature grows as we progress from hourly to daily aggregation timescales and beyond. Thermodynamic effects still play an important role in controlling the maximum water-holding capacity of the atmosphere and therefore peak rainfall intensity, but the observational evidence shows that, beyond a few hours, storm totals become increasingly dominated by dynamical factors. The conclusion is that Clausius–Clapeyron scaling alone cannot be used to reliably predict the net effective changes in rainfall extremes with temperature beyond a few hours. A more general scaling model that takes into account simultaneous changes in intermittency and peak intensity with temperature is proposed to help better disentangle these two phenomena (e.g., peak intensity and intermittency). The new model is applied to a large number of high-resolution rain gauge time series in the United States, and results show that it greatly improves the representation of rainfall extremes with temperature, producing a much more consistent and reliable picture of extremes across scales than using Clausius–Clapeyron only.

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11

Knyazeva, A. G. "Generalization of the Clausius-Clapeyron equation in a coupled thermomechanical model." Journal of Applied Mechanics and Technical Physics 40, no. 6 (November 1999): 1088–96. http://dx.doi.org/10.1007/bf02469178.

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12

Almáši, Miroslav, Vladimír Zeleňák, Arnošt Zukal, Juraj Kuchár, and Jiří Čejka. "A novel zinc(ii) metal–organic framework with a diamond-like structure: synthesis, study of thermal robustness and gas adsorption properties." Dalton Transactions 45, no. 3 (2016): 1233–42. http://dx.doi.org/10.1039/c5dt02437d.

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A novel 3D metal–organic framework with a diamond-like structure has been synthesised and structurally characterized. Adsorption of Ar, CO₂, H₂ and N₂ has been studied. Heats of CO₂ and H₂ adsorption were calculated according to the Clausius–Clapeyron equation.

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13

Rao, T. V. Chandrasekhar, S. B. Ota, and V. C. Sahni. "Effect of Magnetic Field on the Lock-In Transition in Cupric Oxide." Modern Physics Letters B 12, no. 02n03 (February 10, 1998): 85–89. http://dx.doi.org/10.1142/s0217984998000123.

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We present magnetization measurements on polycrystalline CuO over the temperature range 5–300 K using a SQUID magnetometer. The change in sample magnetization at the lock-in transition temperature (212.6 K) as a function of the magnetic field has been found to scale with the field. The results are analyzed in terms of the magnetic analogue of the Clausius–Clapeyron equation.

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14

Zhang, Xuemei, Dong Li, Qinghua Ma, Zheng Wang, and Jingyuan Hao. "STUDY ON A COMPARISON OF THE CLAUSIUS-CLAPEYRON EQUATIONS FOR DESORPTION AND ADSORPTION." International Journal of Innovative Research in Advanced Engineering 9, no. 12 (December 31, 2022): 459–63. http://dx.doi.org/10.26562/ijirae.2022.v0912.01.

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A series of isothermal adsorption experimental data of lean coal has been used to verify a temperature pressure-adsorption equation (TPAE). The enthalpy of the gas adsorption process is calculated by the indefinite integral expression of the Clausius-Clapeyron equation. The lnP vs 1/T plot is shown as a straight line with a negative slope, which illustrate that the adsorption enthalpy is negative, the adsorption process is an exothermic process. High temperature conditions are not conducive to adsorption.

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15

Chen, Linna R., and David J. W. Grant. "Extension of Clausius-Clapeyron Equation to Predict Hydrate Stability at Different Temperatures." Pharmaceutical Development and Technology 3, no. 4 (January 1998): 487–94. http://dx.doi.org/10.3109/10837459809028630.

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16

Koutsoyiannis, Demetris. "Clausius–Clapeyron equation and saturation vapour pressure: simple theory reconciled with practice." European Journal of Physics 33, no. 2 (January 10, 2012): 295–305. http://dx.doi.org/10.1088/0143-0807/33/2/295.

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17

Galleano, Monica, Alberto Boveris, and Susana Puntarulo. "Understanding the Clausius–Clapeyron Equation by Employing an Easily Adaptable Pressure Cooker." Journal of Chemical Education 85, no. 2 (February 2008): 276. http://dx.doi.org/10.1021/ed085p276.

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18

Sánchez-Lavega, Agustı́n, Santiago Pérez-Hoyos, and Ricardo Hueso. "Clouds in planetary atmospheres: A useful application of the Clausius–Clapeyron equation." American Journal of Physics 72, no. 6 (June 2004): 767–74. http://dx.doi.org/10.1119/1.1645279.

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19

Sai, Kateryna. "RESEARCH INTO PECULIARITIES OF PHASE TRANSITIONS DURING THE DISSOCIATION OF GAS HYDRATES." JOURNAL of Donetsk Mining Institute, no. 2 (2021): 51–59. http://dx.doi.org/10.31474/1999-981x-2021-2-51-59.

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Purpose. Analytical study of the dissociation process of gas hydrates taking into account the peculiarities of phase transitions occurring during their dissociation and described by the Clausius-Clapeyron equation. Methods. The research uses an integrated approach, which includes the analysis and generalization of literature sources devoted to studying the peculiarities and thermobaric properties of gas hydrates; processes of hydrate formation and accumulation; methods for the development of gas hydrate deposits and technologies for extracting the methane gas from them; analytical calculations of phase transitions of gas hydrates. Findings. The conditions for the formation of gas hydrate deposits have been analyzed and the peculiarities of stable existence of gas hydrates have been revealed. The existing experience in the development of gas hydrate technologies by leading scientists, world research laboratories, advanced design institutes and organizations is summarized. The mechanism of hydration formation in rocks is studied and some classifications of gas hydrate deposits occurring in sedimentary rock stratum are presented. It has been determined that gas hydrates in natural conditions usually occur not only in the form of pure hydrate reservoirs, but most often contain a certain share of rock intercalations, which makes the deposit structure heterogeneous. The mechanisms of hydrate formation and dissociation of gas hydrates have been revealed. It has been determined that the Clausius-Clapeyron equation in a modified form can be used to describe phase transitions both during the formation and dissociation of gas hydrates, taking into account the deposit heterogeneity. Originality. The Clausius-Clapeyron equation for the analysis of phase transformations in solid phases during hydrate formation and dissociation of gas hydrates is defined more exactly, taking into account the consumption of additional heat due to the influence of the properties of rock intercalations. Practical implications. The research results are useful for designing the rational thermobaric parameters (pressure and temperature) in the dissociation of natural or technogenic gas hydrates, as well as for optimal control of the kinetics of the process.

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20

Koutsoyiannis, Demetris. "Corrigendum: Clausius–Clapeyron equation and saturation vapour pressure: simple theory reconciled with practice." European Journal of Physics 33, no. 4 (May 25, 2012): 1021. http://dx.doi.org/10.1088/0143-0807/33/4/1021.

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21

Caurie, Matthew. "Misapplication of the Clausius-Clapeyron equation for estimating heats of adsorption in foods." International Journal of Food Science & Technology 48, no. 3 (November 23, 2012): 596–600. http://dx.doi.org/10.1111/ijfs.12004.

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22

Sirota, N. N. "Certain problems of polymorphism (II) Generalized clausius-clapeyron equation and Ostwald's step rule." Crystal Research and Technology 22, no. 11 (November 1987): 1343–81. http://dx.doi.org/10.1002/crat.2170221102.

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23

Rao, N. V. S., and V. G. K. M. Pisipati. "Smectic C to Nematic Phase Transition Studies in NOBA." Zeitschrift für Naturforschung A 40, no. 5 (May 1, 1985): 466–68. http://dx.doi.org/10.1515/zna-1985-0507.

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The variation of density ϱ with temperature of p-n-nonyloxy benzoic acid in its isotropic, nematic and smectic-C phases is presented. The density jumps and the computed thermal expansion coefficient maxima suggest the order of the N - SC and N - I transitions to be first order. The pressure dependence of the transition temperatures as computed from the Clausius- Clapeyron equation and the presence of pretransitional effects at the N - SC and N - I transitions in the nematic phase are discussed.

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24

Ernst, C., G. M. Schneider, A. Würflinger, J. Jadżyn, and R. Dąbrowskib. "Differential Thermal Analysis under High Pressure on 6-TPEB." Zeitschrift für Naturforschung A 52, no. 6-7 (July 1, 1997): 490–92. http://dx.doi.org/10.1515/zna-1997-6-704.

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Abstract The high pressure phase behaviour of a new liquid crystal, belonging to the series l-[4-«-alkylbiphenyl]-2-[4-isothio-cyanato-phenyl] ethane (nTPEB), n = 6, has been studied with differential thermal analysis. The pressure dependence of the phase transitions has been determined up to 300 MPa. No pressure-induced or pressure-limited phases are observed in this pressure range, the phase behaviour, however, depends on the thermal treatment. Enthalpy and volume changes accompanying the phase transitions have been calculated using the Clausius-Clapeyron equation.

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López-Arias, T. "Comment on ‘Clausius–Clapeyron equation and saturation vapour pressure: simple theory reconciled with practice’." European Journal of Physics 33, no. 3 (March 12, 2012): L11—L12. http://dx.doi.org/10.1088/0143-0807/33/3/l11.

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Li, Kang, Wen Hao Niu, and Guo Qiang Zhang. "Dew Points of C₄F₈/N₂ Gas Mixtures." Applied Mechanics and Materials 130-134 (October 2011): 1499–502. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.1499.

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C4F8/N2 gas mixtures are possible substitutes for SF6, because of its good insulation characteristics and low influence to environment. The thrust of this paper is to verify the dew point of C4F8 and C4F8/N2 gas mixtures, the dew points of C4F8/N2 mixtures are achieved using experimentally measuring and theory calculating method. The experimental data obtained is compared to that predicted from the Clausius-Clapeyron equation, Trouton’s rule and vapor pressure equation. The results show that the experimental data verify well with the predictions. So the prediction method can be used to predict the dew point of C4F8/N2 gas mixtures for different charging pressures.

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27

Štencl, Jiří. "Effect of temperature and water activity on heat transfer in parsley leaves in the range of temperatures 10–30 °C." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 55, no. 5 (2007): 181–86. http://dx.doi.org/10.11118/actaun200755050181.

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The equilibrium moisture contents of parsley leaves were measured by the gravimetric dynamic method with continuous recording of changes in sample weight. Consequently water activity values were determined. Henderson equation was found to be a good model both for moisture adsorption and desorption. Isosteric heat of sorption was defined and determined in the temperature range of 10–30 °C. Clausius-Clapeyron equation was used to calculate the isosteric heat of sorption since no dependence on temperature in the analysed range was observed. The isosteric heats of sorption (qnst) were indicated graphic in the form qnst versus moisture content. Values for isosteric heat of sorption ranged from 54.41 to 46.85 kJ/mol.

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Attia, Eman, Jeppe C. Dyre, and Ulf R. Pedersen. "Comparing four hard-sphere approximations for the low-temperature WCA melting line." Journal of Chemical Physics 157, no. 3 (July 21, 2022): 034502. http://dx.doi.org/10.1063/5.0097593.

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By combining interface-pinning simulations with numerical integration of the Clausius–Clapeyron equation, we accurately determine the melting-line coexistence pressure and fluid/crystal densities of the Weeks–Chandler–Andersen system, covering four decades of temperature. The data are used for comparing the melting-line predictions of the Boltzmann, Andersen–Weeks–Chandler, Barker–Henderson, and Stillinger hard-sphere approximations. The Andersen–Weeks–Chandler and Barker–Henderson theories give the most accurate predictions, and they both work excellently in the zero-temperature limit for which analytical expressions are derived here.

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KANIADAKIS, G., U. LUCIA, and P. QUARATI. "PROBABILITY AND TIME OF PHOTOFISSION IN THE QUASI-DEUTERON ENERGY REGION." International Journal of Modern Physics E 02, no. 04 (December 1993): 827–34. http://dx.doi.org/10.1142/s0218301393000376.

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Using results of a previous phenomenological and numerical analysis of the photofission of Bi, Th and U in the QD energy region, we study the photofission probability as the solution of a differential equation of Clausius-Clapeyron type and derive an expression for the time of photofission. We argue about some aspects of the photofission dynamics from a thermodynamical point of view and suggest the introduction of some nuclear thermodynamical quantities. The photofission time statistically formulated on the base of the mean free path of the pn pair inside the fissioning nucleus is also examined.

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30

Masberg, S., C. Ernst, G. M. Schneider, A. Würflinger, and R. Dąbrowski. "Differential Scanning Calorimetry (DSC) under High Pressure on 10-TPEB." Zeitschrift für Naturforschung A 54, no. 5 (May 1, 1999): 287–90. http://dx.doi.org/10.1515/zna-1999-0503.

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Abstract The phase behaviour of a new liquid crystal, belonging to the series l-[4-n-alkyl-biphenyl]-2-[4-isothio-cyanato-phenyl]ethane (nTPEB), n = 10, has been investigated with differential scanning calorimetry at ambient and high pressure. The phase behaviour depends on the thermal treatment. Phase transition temperatures have been determined as a function of pressure up to 300 MPa. No pressure-induced or pressure-limited phases are observed in this pressure range. Enthalpy-and volume-changes accompanying the phase transitions have been calculated using the Clausius-Clapeyron equation.

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31

Urban, Stanisław, Maria Massalska-Arodź, Albert Würflinger, and Krzysztof Czupryński. "Pressure-Temperature Phase Diagrams for four 4,4'-Dialkylbiphenyl Compounds." Zeitschrift für Naturforschung A 57, no. 8 (August 1, 2002): 641–44. http://dx.doi.org/10.1515/zna-2002-0801.

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Cm-CnThe high pressure phase behaviour of four 4,4'-dialkylbiphenyl compounds (, m = 5, 6,7, n = 6, 7) has been studied with differential thermal analysis. The pressure dependence of the phase transitions has been determined up to 200 MPa. In one substance a pressure limited and in another a pressure induced phase was observed. Volume changes accompanying the transitions to the isotropic phase were calculated using the Clausius-Clapeyron equation and the enthalpy changes from DSC measurements at 1 atm. They are compared with the data for other two-ring compounds.

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Hoc, Nguyen Quang, Bui Duc Tinh, Nguyen Duc Hien, and Le Hong Viet. "On the Jumps of Volume, Enthalpy and Entropy at the Melting Point, the Thermal Conductivity and Thermal Diffusivity for F.C.C. Au: the Temperature- and Pressure-Dependences." Uspehi Fiziki Metallov 22, no. 4 (December 2021): 511–30. http://dx.doi.org/10.15407/ufm.22.04.511.

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The melting temperature, the jumps of volume, enthalpy and entropy at the melting point, the isothermal compressibility, the thermal expansion coefficient, the heat capacity at constant volume, the Grüneisen parameter, the Debye temperature, the electrical resistivity, the thermal conductivity, and the thermal diffusivity for defective and perfect f.c.c. metals are studied by combining the statistical moment method (SMM), the limiting condition of the absolute stability of the crystalline state, the Clapeyron–Clausius equation, the Debye model, the Grüneisen equation, the Wiedemann–Franz law, and the Mott equation. Numerical calculations are carried out for Au under high temperature and pressure. The calculated melting curve of Au is in good agreement with experiments and other calculations. Obtained results are predictive and orient towards new experiments.

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Wang, Xi-Yu, Xin-Yue Bao, Yu Huang, Zhong-Wai Li, Jia-Hua Yong, Yong-Ping Wu, Guo-Lin Feng, and Gui-Quan Sun. "Physical Explanation for Paradoxical Climate Change in Semi-Arid Inland Eurasia Based on a Remodeled Precipitation Recycling Ratio and Clausius–Clapeyron Equation." Atmosphere 14, no. 2 (February 14, 2023): 376. http://dx.doi.org/10.3390/atmos14020376.

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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.

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Al-Zaid, Khairya, Saed Akashah, Fathi Owaysi, G. V. Jeffreys, Yu A. Eltekov, and C. Mumford. "Adsorption of Aromatic Compounds from Solutions on Molecular Sieve 13X." Adsorption Science & Technology 4, no. 3 (September 1987): 196–210. http://dx.doi.org/10.1177/026361748700400305.

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Measurements of the equilibrium extent of adsorption of individual aromatic hydrocarbons: mono, di, trinuclear aromatic and heterocyclo compounds from iso-octane solutions by molecular sieves 13X were carried out at 303 and 343 K and at concentrations up to 5 wt.% The limiting values of adsorption were essentially determined by using modified Brunauer-Emmett-Teller equation (BET). The coverages and numbers of adsorbate molecules occupied in the unit cell of the molecular sieves were calculated at different temperatures. The isosteric heats of adsorption of aromatic hydrocarbons were also determined using Clausius-Clapeyron equation. It was found that the heats of adsorption of aromatic compounds varied from 4 to 60 kJ mol-1

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Li, Dong, Qinghua Ma, Xuemei Zhang, Yaling Wei, and Jingyuan Hao. "STUDY ON THE CALCULATION AND APPLICATION OF THE UNIT ISOSTERIC ADSORPTION ENTHALPY." International Journal of Innovative Research in Advanced Engineering 9, no. 11 (November 30, 2022): 453–58. http://dx.doi.org/10.26562/ijirae.2022.v0911.03.

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A series of isothermal adsorption experimental data of lean coal and fat coal has been converted into a temperature-pressure-adsorption equation. The slop of the lnP vs 1/T straight line of Clausius-Clapeyron equation proves that physical adsorption is an exothermic process. The Unit Isosteric Adsorption Enthalpy (UIAE, KJ•mol-1•cm-3•g) is defined as a unit adsorbed amount enthalpy at a fixed adsorbed amount andthe calculation method is presented. The UIAE calculation results prove the surface of the adsorption medium is not uniform, and the interaction between the adsorption molecules occurs. At the same isosteric adsorption condition, lean coal has higher priority to carry out the exothermic process than the fat coal.

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Vega-Gálvez, A., R. Lemus-Mondaca, P. Fito, and A. Andrés. "Note: Moisture Sorption Isotherms and Isosteric Heat of Red Bell Pepper (var. Lamuyo)." Food Science and Technology International 13, no. 4 (August 2007): 309–16. http://dx.doi.org/10.1177/1082013207082530.

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Sorption isotherms of red pepper (var. Lamuyo) were determined at three temperatures (10, 20 and 30°C) in a range of water activity from 0.10 to 0.96. BET, GAB, Halsey, Herderson, Caurie, Smith, Oswin and Iglesias—Chirife equations were tested for modelling the sorption isotherms. The statistical evaluation of fit quality of the preceding models showed good results using the BET, GAB, Halsey and Iglesias—Chirife models on experimental sorption data. The BET and GAB models showed monolayer moisture contents from 0.07 to 0.10 g water/g (d.b.); however, they did not show direct dependence on temperature. The Clausius—Clapeyron equation satisfactorily determined the sorption isosteric heats, which were found to increase as the moisture content decreased; the desorption heat (74.2kJ/mol) was higher than that of adsorption heat (36.9kJ/mol). The preceding experimental data showed a good quality fit when evaluated with the Tsami equation.

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Sawhney, Ish K., Girdhari R. Patil, and Bikram Kumar. "Effect of temperature on the moisture sorption isotherms of a heat-treated whole milk product, khoa." Journal of Dairy Research 58, no. 3 (August 1991): 329–35. http://dx.doi.org/10.1017/s0022029900029903.

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SummaryMoisture sorption isotherms of khoa were determined at 15, 25, 35 and 45 °C over a water activity (aw) range of O·l 1–0·97. The isotherms were sigmoid (Type II) and were fitted to the Guggenheim–Anderson–de Boer (GAB) equation (Bizot, 1983). The aw of freshly made khoa was found to be 0·96. The aw of khoa increased with increasing temperature up to 0·9; above this the effect of temperature on aw diminished. The monolayer moisture content of khoa decreased with increasing temperature. The equations describing the temperature dependence of GAB constants were determined in the form of the Clausius–Clapeyron equation. The net isosteric heat of desorption of khoa decreased rapidly until a moisture level of 0·1 g/g solids, and approached a constant value of 0·43 kJ/mol above a moisture level of 0·25 g/g solids.

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Ma, Wei, Lianhai Zhang, and Chengsong Yang. "Discussion of the applicability of the generalized Clausius–Clapeyron equation and the frozen fringe process." Earth-Science Reviews 142 (March 2015): 47–59. http://dx.doi.org/10.1016/j.earscirev.2015.01.003.

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39

Qadeer, Riaz, and Javed Hanif. "The Isosteric Heat of Adsorption of Sr2+, Ce3+, Sm3+, Gd3+, Th4+ and UO22+ Ions on Activated Charcoal." Adsorption Science & Technology 11, no. 4 (December 1994): 201–8. http://dx.doi.org/10.1177/026361749401100402.

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The values of the isosteric heat of adsorption (qst) of Sr2+, Ce3+, Sm3+, Gd3+, Th4+ and UO22+ ions on activated charcoal have been calculated at different surface coverages and temperatures by applying the Clausius–Clapeyron equation. The variation of qst with surface coverage indicates the heterogeneous nature with varying activities of the activated charcoal surface. The behaviour of qst values with temperature suggests that two types of adsorption processes occur simultaneously; one with a small activation energy and the other with a large activation energy. A large increase in the qst values indicates that increasing temperature changes the physical adsorption process to chemisorption.

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Jones, David E. G., Ruiping Wang, and Anne-Marie Turcotte. "The effect of pressure and heating rate on the melting behavior of indium and tin." Canadian Journal of Chemistry 84, no. 3 (March 1, 2006): 407–11. http://dx.doi.org/10.1139/v05-256.

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The dependence of the phase transition behavior of indium and tin on pressure and heating rate has been investigated using heat flow calorimetry (HFC). The work has shown a significant influence of heating rate on the form of the melting curve, onset temperature for both indium and tin, as well as the enthalpy of fusion for indium. Based on the result for the dependence of onset temperature on pressure, the volume changes on fusion have been estimated using the Clausius–Clapeyron equation and compared with literature results.Key words: indium, tin, high pressure, heat flow calorimetry calibration, fusion temperature, enthalpy of fusion.

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Gomes, Michelle G., Nattácia R. A. F. Rocha, Alex A. Moura, Nadine P. Merlo, Moilton R. Franco Júnior, and Patrisia O. Rodrigues. "Prediction of Liquid Molar Volume and Heat of Vaporization of Fatty Acids Using an Equation of State." Current Physical Chemistry 10, no. 3 (November 4, 2020): 189–98. http://dx.doi.org/10.2174/1877946809666191129110018.

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Background:: The liquid molar volume (V) and the heat of vaporization (ΔHVAP) of four fatty acids (n-Heptanoic acid, Hexadecanoic acid, n-Hexanoic acid and n- Dodecanoic acid) have been estimated. Objective:: This paper aims to calculate the liquid molar volume and the heat of vaporization of four fatty acids under the critical point using two traditional equations of state: Peng-Robinson (PR) [21] and Soave-Redlich-Kwong. Methods: The area rules method applicable to obtaining the saturation pressure of the compounds has been used. The properties of the acids investigated in this work have been compared with those provided by literature. For molar volumes, the equations of state have given improved predictions when compared to traditional equations such as Rackett equation and so on. According to the vapor enthalpy calculations, no reference value was required. Results: In general, the Clausius-Clapeyron equation provides a better estimation of the vaporization enthalpy of fatty acids when Soave-Redlich-Kwong (SRK) equation was used. The heat of vaporization for fatty acids can be calculated with good reliability in comparison with the Watson equation if suitable equation of state is used. Conclusion: Accurate results for heat of vaporization can be reached in comparison with the Watson equation if the reliable equation of state is used.

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Anishchenko, Oleksandr, Volodymyr Kukhar, Viktor Agarkov, and Alla Vorobeva. "Mathematical model development for superplastic forming of sheet shells by subliming agent gas pressure." E3S Web of Conferences 135 (2019): 01002. http://dx.doi.org/10.1051/e3sconf/201913501002.

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The authors presented in the article an analytical model of superplastic forming of spherical shells by pressure of the gas (gaseous phase) created upon sublimation of sublimate agent. Sublimate was placed in a hermetic cavity between the workpiece and the presser cover and heated to the temperature of its sublimation. The model uses the Berthelot equation for the state of real gases, the Bernoulli relation, and the F. Jovane equations for adjusting the shell forming pressure as a function of its relative height, the heat balance equation for the sublimation process, and the Clausius-Clapeyron relation for sublimation of substances. The authors showed that the superplastic forming pressure control can be effectively applied by the way of change in the forming temperature relative to temperature of sublimate agent sublimation. The experimental results of forming of shells from aluminum alloys AlMg3Mn, AlMg5Mn and AlMg6Mn, confirming theoretical calculations of the velocity and temperature conditions of superplastic forming by the sublimating agent pressure.

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Bykiv, Nazarii, Volodymyr Iasnii, Petro Yasniy, and Robert Junga. "Thermomechanical analysis of nitinol memory alloy behavior." Scientific journal of the Ternopil national technical university 102, no. 2 (2021): 161–67. http://dx.doi.org/10.33108/visnyk_tntu2021.02.161.

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Shape memory alloys are functional materials characterized by the effect of shape memory and superelasticity. Due to these properties, they are widely used, particularly, in bioengineering, aeronautics, robotics and civil engineering. The temperatures of phase transformations and the influence of external temperature and strain rate on the functional and mechanical characteristics of Ni55.75Ti44.15 shape memory alloy are investigated in this paper. The temperature of alloy phase transformations is obtained by differential scanning calorimetry (DSC) in the temperature range from -70°C to 70°C. Diagrams of differential scanning calorimeters at different heating and cooling rates of Ni55.75Ti44.15 alloy is constructed and analyzed. Samples for mechanical tests are made of round rod 8 mm in diameter. The samples working area is 12.5 mm in length and 4 mm in diameter. Mechanical tests are carried out at temperatures close to the maximum value of the completion temperature of martensitic-austenitic transformation Af = 14.7°C. Diagrams of deformation under uniaxial tension are constructed and stresses of phase transformations, Young's modulus and relative elongations of transformation areas at different loading speeds and exterior temperatures are determined. Using Clausius-Clapeyron formula, it is shown that with simultaneous changes in temperature and strain rate, the stresses of phase transformations are largely due to changes in temperature rather than load rates. The coefficients of Clausius-Clapeyron equation for superelastic Ni55.75Ti44.15 alloy with shape memory, which are consistent with those known in the literature, are determined.

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Govor, G. A., A. O. Larin, V. I. Mitsiuk, G. S. Rimskiy, and T. M. Tkachenkа. "Magnetocaloric properties of the single crystal Mn0.99Fe0.01As." Proceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series 55, no. 1 (March 26, 2019): 118–24. http://dx.doi.org/10.29235/1561-2430-2019-55-1-118-124.

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The Stockbargard – Bridgman method yielded single crystals Mn0.99Fe0.01As. The effect of an external magnetic field with an intensity of up to 10 T on phase transitions in the single crystal Mn0.99Fe0.01As is studied. It is established that the magnetostructural phase transition in Mn0.99Fe0.01As is accompanied by a change in the entropy ΔSm, which is due to the transformation of the crystal structure. At temperatures above the temperature of the magnetostructural transition Tu = 290 K, the existence of an unstable magnetic structure is obtained. The magnetocaloric characteristics of the material under study are determined by an indirect calculation method based on the Maxwell thermodynamic relations and the Clapeyron – Clausius equation.

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Würflinger, A., M. Sandmann, and W. Weissflog. "PVT Measurements on 3-Cyanobenzyl 2,5-bis(4-n-octyloxybenzoyl- oxy)benzoate up to 250 MPa and 423 K." Zeitschrift für Naturforschung A 55, no. 9-10 (October 1, 2000): 823–27. http://dx.doi.org/10.1515/zna-2000-9-1012.

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Abstract P, Vm , T data have been measured for the nematic and isotropic phases of 3-cyanobenzyl 2,5-bis (4-n-octyloxybenzoyloxy)benzoate between 273 and 423 K and up to 250 MPa. The volume changes accompanying the crystal -nematic and nematic -isotropic transitions have been determined. The cor-responding enthalpy changes have been calculated using the Clausius-Clapeyron equation. The p, V m , T data enable also to estimate the volume entropy for the nematic-isotropic transition. It is found that the configurational part of the transition entropy amounts to 80%, this portion being distinctly larger than found in previous studies for conventional rod-like liquid crystals.

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Koutsoyiannis, Demetris. "Reply to ‘Comment on “Clausius–Clapeyron equation and saturation vapour pressure: simple theory reconciled with practice”’." European Journal of Physics 33, no. 3 (March 12, 2012): L13—L14. http://dx.doi.org/10.1088/0143-0807/33/3/l13.

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Würflinger, A., and W. Weissflog. "DTA and p VT Measurements on 4-cyanobenzyI-5- (4-n-octyloxybenzoyloxy)-2-undecyloxybenzoate up to 250 MPa and 383 K." Zeitschrift für Naturforschung A 55, no. 11-12 (December 1, 2000): 936–40. http://dx.doi.org/10.1515/zna-2000-11-1219.

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Abstract The phase diagram of 4-cyanobenzyl-5-(4-«-octyloxybenzoyloxy)-2-undecyloxybenzoate (4CNOUB) has been established with differential thermal analysis (DTA). The pressure range for the smectic A phase is limited, resulting in a triple point at 165 MPa and 378.26 K. p, Vm, T data have been measured for the smectic and istotropic phases of 4CNOUB between 243 and 383 K and up to 250 MPa. The volume changes accompanying the crystal - smectic and scmectic - isotropic transitions have been deter-mined. The corresponding enthalpy changes have been calculated using the Clausius-Clapeyron equation. The p, Vm, T data enable also to estimate the volume entropy for the smectic - isotropic transition and the volume dependence of the clearing temperature.

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Crossley, S., W. Li, X. Moya, and N. D. Mathur. "Large electrocaloric effects in single-crystal ammonium sulfate." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2074 (August 13, 2016): 20150313. http://dx.doi.org/10.1098/rsta.2015.0313.

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Electrocaloric (EC) effects are typically studied near phase transitions in ceramic and polymer materials. Here, we investigate EC effects in an inorganic salt, namely ammonium sulfate (NH 4 ) 2 SO 4 , with an order–disorder transition whose onset occurs at 223 K on cooling. For a single crystal thinned to 50 μm, we use a Maxwell relation to find a large isothermal entropy change of 30 J K −1 kg −1 in response to a field change of 400 kV cm −1 . The Clausius–Clapeyron equation implies a corresponding adiabatic temperature change of 4.5 K. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’.

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Larbi, Ahmed Amine, Akil Loumani, Ahmed Mediani, Asma Masmoudi, Fatima Zohra Bnoumachich, Djaber Abdelkarim, Tigani Cherif, and Ahmed Harrouz. "Inﬂuence of temperature and Thermodynamic Analysis on Adsorption/Desorption Isothermss for green menth." Algerian Journal of Renewable Energy and Sustainable Development 5, no. 1 (June 15, 2023): 85–93. http://dx.doi.org/10.46657/ajresd.2023.5.1.11.

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The objective of this study is to experimentally determine the sorption isotherms and thermodynamic properties of green mint after undergoing thermal and biochemical treatment. The method employed is the gravimetric method using saturated saline solutions at various temperatures. In order to model and predict the hygroscopic behavior during drying and storage, we have utilized developed mathematical models (such as the Langmuir, GAB, modified BET, Peleg models, etc.). The adjustment and optimization of these models will be conducted using statistical techniques to analyze the obtained data. The isosteric desorption heats of green mint will be calculated using the Clausius-Clapeyron equation. This study will provide an expression to predict the thermodynamic properties of green mint.

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Scheff, Jacob, and Dargan M. W. Frierson. "Scaling Potential Evapotranspiration with Greenhouse Warming." Journal of Climate 27, no. 4 (February 10, 2014): 1539–58. http://dx.doi.org/10.1175/jcli-d-13-00233.1.

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Abstract Potential evapotranspiration (PET) is a supply-independent measure of the evaporative demand of a terrestrial climate—of basic importance in climatology, hydrology, and agriculture. Future increases in PET from greenhouse warming are often cited as key drivers of global trends toward drought and aridity. The present work computes recent and “business as usual” future Penman–Monteith PET fields at 3-hourly resolution in 13 modern global climate models. The percentage change in local annual-mean PET over the upcoming century is almost always positive, modally low double-digit in magnitude, usually increasing with latitude, yet quite divergent between models. These patterns are understood as follows. In every model, the global field of PET percentage change is found to be dominated by the direct, positive effects of constant-relative-humidity warming (via increasing vapor deficit and increasing Clausius–Clapeyron slope). This direct-warming term accurately scales as the PET-weighted (warm-season daytime) local warming, times 5%–6% °C−1 (related to the Clausius–Clapeyron equation), times an analytic factor ranging from about 0.25 in warm climates to 0.75 in cold climates, plus a small correction. With warming of several degrees, this product is of low double-digit magnitude, and the strong temperature dependence gives the latitude dependence. Similarly, the intermodel spread in the amount of warming gives most of the spread in this term. Additional spread in the total change comes from strong disagreement on radiation, relative humidity, and wind speed changes, which make smaller yet substantial contributions to the full PET percentage change fields.

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Journal articles on the topic 'Clausius-Clapeyron equation'

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