Progress in Engineering Thermodynamics and Kinetics
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Progress in Engineering Thermodynamics and Kineticsendaily1Mon, 25 Dec 2023 00:00:00 +0330Mon, 25 Dec 2023 00:00:00 +0330Thermodynamic modeling of vapor-liquid equilibrium systems including biodiesel in high and low pressures using cubic equations of state
http://jpetk.semnan.ac.ir/article_8325.html
In the work, vapor-liquid equilibrium (VLE) of pure and binary mixtures of the systems including fatty acid Ethyl or Methyl esters and alcohols is analyzed by two simple cubic equations of state; Cubic-Square-Well (CSW EoS) and the Peng-Robinson (PR EoS). To achieve this purpose, first, the parameters of equations of state for pure systems are optimized using experimental vapor pressure and liquid density. Two models show accepted accuracy, however, the PR EoS with AARD=1.01% demonstrations better results for pure systems. Then the results of the pure systems are used to correlate the phase behavior of the binary mixtures in low and high pressure using one binary interaction parameter in equilibrium systems. The results for binary fatty acid ester systems show deviations as AARD=0.45% and AARD=0.23% for PR and CSW EoSs, respectively. For alcohol+fatty acid ester binary systems the pressure deviations are AARD=5.04% and AARD=14.14% for PR and CSW EoSs, respectively. Therefore, the results show that the CSW and PR equations of state can be applied to calculate the phase behavior of these types of systems with good accuracy and simplicity, therefore, can be used in designing, modeling, and optimization of the biodiesel units.Application of a simple cubic regularity for liquid density predictions and comparison with GMA EOS
http://jpetk.semnan.ac.ir/article_8326.html
Based on a cubic regularity, (2Z-1)v is nearly linear versus molar density at isothermal condition for each liquids, where Z and v is compressibility factor and molar volume, respectively. Using the regularity, a cubic equation of state can be obtained. The temperature-dependent parameters of the cubic EOS are obtained through correlation of pu..re liquid density of several substances at various pressures and temperatures. The results of the cubic EOS are in good agreement with the experimental data. In addition, the results of the cubic EOS are compared with the Goharshadi-Morsali-Abbaspour (GMA) EOS.Thermodynamic modeling of clathrate hydrate stability conditions in methane + 1-methylpiperidine/2-methylpiperidine + water system
http://jpetk.semnan.ac.ir/article_8327.html
There are three typical thermodynamic models to determine structure H (sH) hydrate stability conditions, i.e. van der Waals-Platteeuw based model developed by Mehta and Sloan, the Chen-Guo model introduced by Chen and Guo, and the Klauda-Sandler model applied by Sinehbaghizadeh et al. and other researchers. These thermodynamic models are typically used for water-immiscible or slightly soluble sH hydrate formers e.g. methylcyclopentane, methylcyclohexane, 2,2-dimethylbutane, etc. However, some sH clathrate hydrate formers are soluble in water such as 1-methylpiperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, and hexamethyleneimine. In this study, Chen-Guo and Mehta-Sloan models were used to model sH hydrate stability conditions for 1-methylpiperidine / 2-methylpiperidine with methane as a help gas. The aqueous phase behavior containing 1-methylpiperidine / 2-methylpiperidine is modeled using the NRTL activity coefficient model. Although both Chen-Guo and Mehta-Sloan models show errors of less than 1%, Mehta-Sloan model results are in a better agreement with the experimental data with 0.10% average absolute error in comparison with Chen-Guo model results with 0.38% average absolute error for 1-methylpiperidine while there is not much difference for 2-metylpiperidine when using both models in which %AAD for both models are approximately the same, i.e. 0.79%.Subcritical water extraction of Foeniculum vulgare Mill (Fennel) essential oil
http://jpetk.semnan.ac.ir/article_8328.html
This study extracted the essential oil from Foeniculum vulgare Mill seeds (Fennel) with subcritical water and compared it to the method of Hydro distillation. The important ingredient of essential oil is trans-Anethole. Identification of substances in essential oil and their amount were performed by GC and GC/MS analysis. The effect of temperature, mean particle size, flow rate, and extraction time on the amount, and quality of subcritical water extraction was studied. To facilitate the experiments and investigate the effect of the parameters in their extraction and interaction, used the method of response surface with a central composite design (CCD). The optimum conditions for trans-Anethole extraction happened at a temperature of 125 &deg;C and a mean particle size between 0.5 and 0.71 mm in 65 min and a flow rate of 25.1 mL/min. The total maximum yield (0.02345 mg essence/g dry sample) obtained at the optimal conditions was more than that achieved by the Hydro distillation method (0.01322 mg essence/g dry sample).An overview of determination of Youngâ€™s modulus by AFM in various fields
http://jpetk.semnan.ac.ir/article_8537.html
The Atomic Force Microscope (AFM) is a powerful tool for studying the properties and structures of materials at the nanometer scale. Unlike most surface analysis methods, it has no restrictions on surface types or their environment. This versatility allows AFM to investigate a wide range of materials, including conductive, insulating, soft, hard, cohesive, powdered, biological, organic, and inorganic. As such, it finds applications in diverse scientific fields such as chemistry, surface chemistry, polymer science, physics, molecular engineering, semiconductor science, biology, and medicine. Beyond its ability to image surfaces, AFM can also measure mechanical properties like Young's modulus. Young's modulus, also known as the modulus of elasticity (E), is defined as the ratio of stress to strain in the elastic region. This value reflects the stiffness of a material and changes with temperature. This paper explores the application of AFM in measuring Young's modulus across various scientific disciplines.Removal of lead ions from aqueous solutions using the micellar-enhanced ultrafiltration process: Response surface methodology optimization
http://jpetk.semnan.ac.ir/article_8551.html
AbstractIn this study, the micellar-enhanced ultrafiltration (MEUF) separation process was employed to determine the removal percentage of lead ions from aqueous solutions. The effect of various parameters, such as the initial concentration of lead (200-400 mg/l) , operating pressure (2-4 bar) and molar concentration ratio of the surfactant SDS to the metal (5-10), was investigated using the response surface methodology (RSM) and Box-Behnken design (BBD). The number of experiments designed by this scheme was 15 and the importance of the effective parameters and their binary interactions were evaluated using the analysis of variance (ANOVA). The obtained results showed that the proposed model has optimal accuracy and efficiency in the prediction of the lead rejection percentage. The responses predicted by the model showed that the MEUF process could lead to a high rejection rate of Pb(II) ions (99.90 %) at optimal conditions.Keywords: Lead, Surfactant, Membrane processes, Micellar-enhanced ultrafiltration, Optimization