Thermal desorption under conditions of freely occurring readsorption: A method for evaluation of the experimental data

1984 ◽  
Vol 49 (10) ◽  
pp. 2176-2186
Author(s):  
Jan Pavlíček
Keyword(s):  
Experimental Data ◽  
Thermal Desorption ◽  
Entire Range ◽  
Differential Entropy ◽  
Equilibrium Conditions ◽  
Kinetic Order ◽  
Desorption Curve ◽  
Differential Enthalpy ◽  
Unified Description

A method is proposed which permits to determine the differential enthalpy, differential entropy and kinetic order of desorption from the thermal desorption experiments carried out under close-to-equilibrium conditions. The main preference of the proposed method can be seen in the possibility to use for evaluation the entire range of the desorption curve, as well as, in the unified description of the most frequently used types of heating. The approximations enabling such a unified description lead to deviations which are, in major, mutually eliminated and the resulting error is therefore negligible if compared with the accuracy of the experimental data.

scholarly journals Hygroscopic Behavior and Thermodynamic Properties of Ziziphus joazeiro Mart. Kernel Flour

2020 ◽  
Vol 8 (3) ◽  
pp. 50
Author(s):  
Hanndson Araujo Silva ◽  
Josivanda Palmeira Gomes ◽  
Alexandre José de Melo Queiroz
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Isosteric Heat ◽  
Type Ii ◽  
Differential Entropy ◽  
Differential Enthalpy ◽  
Gab Model ◽  
Hygroscopic Behavior ◽  
Best Fit

The hygroscopic and thermal behavior of kernel flour from Ziziphus joazeiro fruits were investigated. Adsorption isotherms were obtained at temperatures of 293, 303 and 313 K and adjusted to GAB, Oswin and Peleg models. The best fit of the experimental data was obtained with the GAB model with R² values> 0.994 and mean percentage deviation P <10%. The isotherms obtained were sigmoidal type II. Isosteric heat and other thermodynamic properties were calculated as a function of moisture content. Adsorption isosteric heat decreased exponentially with increasing moisture content and differential entropy increased with moisture content, while differential enthalpy decreased. The theory of compensation confirmed that these properties are dependent on moisture content. The isotherms presented a spontaneous and enthalpy process.

Excess molar volumes and viscosities of binary mixtures of some polyethers with propylamine at 298.15 K

2002 ◽  
Vol 80 (5) ◽  
pp. 467-475 ◽  
Author(s):  
Amalendu Pal ◽  
Rakesh Kumar Bhardwaj
Keyword(s):  
Experimental Data ◽  
Viscous Flow ◽  
Binary Mixtures ◽  
Entire Range ◽  
Excess Volume ◽  
Excess Molar Volumes ◽  
Liquid Mixtures ◽  
Molar Volumes ◽  
Binary Liquid ◽  
Volume Viscosity

Excess molar volumes (VmE) and dynamic viscosities (η) have been measured as a function of composition for binary liquid mixtures of propylamine with 2,5-dioxahexane, 2,5,8-trioxanonane, 2,5,8,11-tetraoxadodecane, 3,6,9-trioxaundecane, and 5,8,11-trioxapentadecane at 298.15 K. The excess volumes are positive over the entire range of composition for the systems propylamine + 2,5-dioxahexane, and + 3,6,9-trioxaundecane, negative for the systems propylamine + 2,5,8,11-tetraoxadodecane, and + 5,8,11-trioxapentadecane, and change sign from positive to negative for the remaining system propylamine + 2,5,8-trioxanonane. From the experimental data, deviations in the viscosity (Δln η) and excess energies of activation for viscous flow (ΔG*E) have been derived. These values are positive for all mixtures with the exception of propylamine + 2,5-dioxahexane.Key words : excess volume, viscosity, binary mixtures.

scholarly journals Representative subsampling of sedimenting blood

2019 ◽  
Vol 475 (2227) ◽  
pp. 20190223
Author(s):  
Bhargav Rallabandi ◽  
Janine K. Nunes ◽  
Antonio Perazzo ◽  
Sergey Gershtein ◽  
Howard A. Stone
Keyword(s):  
Experimental Data ◽  
Entire Range ◽  
Original Sample ◽  
Sectional Area ◽  
Cross Sectional ◽  
Design Considerations ◽  
Simple Tool ◽  
Sedimentation Model ◽  
Practical Challenge ◽  
Larger Sample

It is often necessary to extract a small amount of a suspension, such as blood, from a larger sample of the same material for the purposes of diagnostics, testing or imaging. A practical challenge is that the cells in blood sediment noticeably on the time scale of a few minutes, making a representative subsampling of the original sample challenging. Guided by experimental data, we develop a Kynch sedimentation model to discuss design considerations that ensure a representative subsampling of blood, from a container of constant cross-sectional area, for the entire range of physiologically relevant hematocrit over a specified time of interest. Additionally, we show that this design may be modified to exploit the sedimentation and perform subsampling to achieve either higher or lower hematocrit relative to that of the original sample. Thus, our method provides a simple tool to either concentrate or dilute small quantities of blood or other sedimenting suspensions.

scholarly journals Study of Acoustical Parameters in Binary Liquid Mixture Containing 1-Butanol and Hexane at Temperatures 313.15 K, 318.15 K and 323.15 K

2013 ◽  
Vol 18 ◽  
pp. 1-7
Author(s):  
C.H. Srinivasu ◽  
K. Anil Kumar ◽  
S.K. Fakruddin ◽  
K. Narendra ◽  
T. Anjaneyulu
Keyword(s):  
Experimental Data ◽  
Molecular Interactions ◽  
Acoustic Impedance ◽  
Entire Range ◽  
Liquid Mixture ◽  
Adiabatic Compressibility ◽  
Binary Liquid Mixture ◽  
Acoustical Parameters ◽  
Binary Liquid ◽  
Different Temperatures

The values of ultrasonic velocity (u), density (ρ), and viscosity (η) have been measured experimentally in the binary liquid mixture containing 1-butanol and hexane over the entire range of composition at different temperatures 313.15 K, 318.15 K and 323.15 K. This experimental data have been used to calculate the acoustical parameters such as adiabatic compressibility (β), free length (Lf), molar volume (Vm) and acoustic impedance(z). The results have been qualitatively used to explain the molecular interactions between the components of the liquid mixture.

scholarly journals Molecular Interaction Studies in Ternary Liquid Mixtures of Quinoline at Varying Temperatures

2008 ◽  
Vol 4 (2) ◽  
pp. 412-419
Author(s):  
Ch. Kavitha ◽  
Dr. A. Ratnakar ◽  
Dr. K. Narendra
Keyword(s):  
Experimental Data ◽  
Ultrasonic Velocity ◽  
Entire Range ◽  
Composition Range ◽  
Liquid Mixtures ◽  
Acoustic Parameters ◽  
Viscosity Deviation ◽  
Free Energy Of Activation ◽  
Excess Parameters ◽  
Gibb’S Free Energy

Density r, Viscosity η, and ultrasonic velocity u, have been measured in pure Quinoline, o-cresol, m-cresol, p-cresol and methanol and in their ternary liquid mixtures with quinoline and methanol as common components at 303.15, 308.15, 313.15 and 318.15K over the entire range of composition. From these experimental data, various thermo-acoustic parameters such as excess molar volume VmE, excess ultrasonic velocity uE, viscosity deviation Δη and excess Gibb’s free energy of activation for viscous flow ΔG*E have been calculated. The deviation/excess parameters were plotted against the mole fraction of quinoline over the whole composition range. The observed negative and positive values of deviaiton/excess thermo-acoustic parameters were explained on the basis of intermolecular interactions present in these mixtures.

scholarly journals SORPTION ISOTHERMS AND THERMODYNAMIC ANALYSIS OF SEED FRUITS USED TO OBTAIN VEGETABLE OIL

2015 ◽  
Vol 45 (1) ◽  
pp. 21-26
Author(s):  
K. S. SILVA ◽  
J. T. ROMERO ◽  
M. A. MAURO
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Sorption Process ◽  
Grape Seeds ◽  
Differential Enthalpy ◽  
Compensation Theory ◽  
Enthalpy And Entropy ◽  
Melon Seeds

Sorption isotherms of papaya, melon and grape seeds were determined and thermodynamic properties compared. The experiments were carried out at different temperature using the gravimetric method. The Henderson and GAB models were the best which represented the experimental data. Papaya and grape seeds are more stable with larger moisture content than melon seeds at 30°C. Grape seeds presented more resistance to lose water during the dehydration. The differential enthalpy and entropy decreased with increasing moisture content and satisfied the compensation theory. It was found that the sorption process investigated was enthalpy-driven.

Molecular Interaction Studies in Ternary Liquid Mixtures of Quinoline at Varying Temperatures

2013 ◽  
Vol 12 (7) ◽  
pp. 412-419
Author(s):  
Ch. Kavitha ◽  
Dr. A. Ratnakar ◽  
Dr. K. Narendra
Keyword(s):  
Experimental Data ◽  
Ultrasonic Velocity ◽  
Entire Range ◽  
Composition Range ◽  
Liquid Mixtures ◽  
Acoustic Parameters ◽  
Viscosity Deviation ◽  
Free Energy Of Activation ◽  
Excess Parameters ◽  
Gibb’S Free Energy

Density r, Viscosity η, and ultrasonic velocity u, have been measured in pure Quinoline, o-cresol, m-cresol, p-cresol and methanol and in their ternary liquid mixtures with quinoline and methanol as common components at 303.15, 308.15, 313.15 and 318.15K over the entire range of composition. From these experimental data, various thermo-acoustic parameters such as excess molar volume VmE, excess ultrasonic velocity uE, viscosity deviation Δη and excess Gibb’s free energy of activation for viscous flow ΔG*E have been calculated. The deviation/excess parameters were plotted against the mole fraction of quinoline over the whole composition range. The observed negative and positive values of deviaiton/excess thermo-acoustic parameters were explained on the basis of intermolecular interactions present in these mixtures.

Electromigration of Silicon Adatoms on Silicon (111) Surface

2011 ◽  
Vol 6 (2) ◽  
pp. 65-76
Author(s):  
Ekaterina E. Rodyakina ◽  
Sergey S. Kosolobov ◽  
Aleksandr V. Latyshev
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
Effective Charge ◽  
Ex Situ ◽  
Equilibrium Conditions ◽  
Force Microscopy ◽  
Homoepitaxial Growth ◽  
Atomic Force ◽  
Reflection Electron Microscopy

Existence of adatom gradient concentration on surface between step bunches was shown under sublimation, homoepitaxial growth and near equilibrium conditions on silicon (111) surface at above 900 ºС by means of in situ ultrahigh vacuum reflection electron microscopy and ex situ atomic force microscopy. It is experimentally confirmed that adatom have negative (at 1 100 ºС) and positive (at 1 300 ºС) effective charge. We found out the sign of adatom effective charge independent on the supersaturation volume on the surface. On the hasement of experimental data we evaluated the effective charge of adatom at 1 280ºС; this quantity is placed between 0,07 ± 0,01 and 0,17 ± 0,02 of electron unit

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