scholarly journals Toward closure between predicted and observed particle viscosity over a wide range temperature and relative humidity

2020 ◽  
Author(s):  
Sabin Kasparoglu ◽  
Ying Li ◽  
Manabu Shiraiwa ◽  
Markus Petters
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Relative Humidity ◽  
Water Uptake ◽  
Atmospheric Aerosols ◽  
Equilibrium Phase ◽  
Relaxation Method ◽  
Wide Range ◽  
Temperature And Humidity

Abstract. Atmospheric aerosols can exist in amorphous semi-solid or glassy phase states whose viscosity varies with atmospheric temperature and relative humidity. The temperature and humidity dependence of viscosity has been hypothesized to be predictable from the combination of a water-organic binary mixing rule of the glass transition temperature, a glass transition temperature scaled viscosity fragility parameterization, and a water uptake parameterization. This work presents a closure study between predicted and observed viscosity for sucrose and citric acid. Viscosity and glass transition temperature as a function of water content are compiled from literature data and used to constrain the fragility parameterization. New measurements characterizing viscosity of sub-100 nm particles using the dimer relaxation method are presented. These measurements extend the available data of temperature and humidity dependent viscosity to −28 ºC. Predicted relationships agree well with observations at room temperature and with measured isopleths of constant viscosity at ~107 Pa s and warmer than −28 ºC. Discrepancies at colder temperatures are observed for sucrose particle. Simulations with the kinetic multi-layer model of gas-particle interactions suggest that the observed deviations at colder temperature for sucrose can be attributed to kinetic limitations associated with water uptake at the timescales of the dimer relaxation experiments. Using the available information, updated equilibrium phase-state diagrams (−80 ºC 

scholarly journals Toward closure between predicted and observed particle viscosity over a wide range of temperatures and relative humidity

2021 ◽  
Vol 21 (2) ◽  
pp. 1127-1141
Author(s):  
Sabin Kasparoglu ◽  
Ying Li ◽  
Manabu Shiraiwa ◽  
Markus D. Petters
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Citric Acid ◽  
Relative Humidity ◽  
Water Uptake ◽  
Equilibrium Phase ◽  
Relaxation Method ◽  
Wide Range ◽  
Temperature And Humidity

Abstract. Atmospheric aerosols can exist in amorphous semi-solid or glassy phase states whose viscosity varies with atmospheric temperature and relative humidity. The temperature and humidity dependence of viscosity has been hypothesized to be predictable from the combination of a water–organic binary mixing rule of the glass transition temperature, a glass-transition-temperature-scaled viscosity fragility parameterization, and a water uptake parameterization. This work presents a closure study between predicted and observed viscosity for sucrose and citric acid. Viscosity and glass transition temperature as a function of water content are compiled from literature data and used to constrain the fragility parameterization. New measurements characterizing viscosity of sub-100 nm particles using the dimer relaxation method are presented. These measurements extend the available data of temperature- and humidity-dependent viscosity to −28 ∘C. Predicted relationships agree well with observations at room temperature and with measured isopleths of constant viscosity at ∼107 Pa s at temperatures warmer than −28 ∘C. Discrepancies at colder temperatures are observed for sucrose particles. Simulations with the kinetic multi-layer model of gas–particle interactions suggest that the observed deviations at colder temperature for sucrose can be attributed to kinetic limitations associated with water uptake at the timescales of the dimer relaxation experiments. Using the available information, updated equilibrium phase-state diagrams (-80∘C<T<40∘C, temperature, and 0%<RH<100%, relative humidity) for sucrose and citric acid are constructed and associated equilibration timescales are identified.

scholarly journals The Glass Transition Temperature and Temperature Dependence of Activation Energy of Viscous Flow of Ovalbumin

2016 ◽  
Vol 39 (1) ◽  
pp. 13-25
Author(s):  
Karol Monkos
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Viscous Flow ◽  
Solvent Interactions ◽  
Model Free ◽  
Free Volume Model ◽  
Wide Range ◽  
Different Temperatures

Abstract The paper presents the results of viscosity determinations on aqueous solutions of ovalbumin at a wide range of concentrations and at temperatures ranging from 5°C to 55°C. On the basis of these measurements and three models of viscosity for glass-forming liquids: Avramov’s model, free-volume model and power-law model, the activation energy of viscous flow for solutions and ovalbumin molecules, at different temperatures, was calculated. The obtained results show that activation energy monotonically decreases with increasing temperature both for solutions and ovalbumin molecules. The influence of the energy of translational heat motion, protein-protein and protein-solvent interactions, flexibility and hydrodynamic radius of ovalbumin on the rate of decrease in activation energy with temperature has been discussed. One of the parameters in the Avramov’s equation is the glass transition temperature Tg. It turns out that the Tg of ovalbumin solutions increases with increasing concentration. To obtain the glass transition temperature of the dry ovalbumin, a modified Gordon-Taylor equation is used. Thus determined the glass transition temperature for dry ovalbumin is equal to (231.8 ± 6.1) K.

scholarly journals Predicting the influence of particle size on the glass transition temperature and viscosity of secondary organic material

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Markus Petters ◽  
Sabin Kasparoglu
Keyword(s):  
Particle Size ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Melting Point ◽  
Critical Role ◽  
Particle Diameter ◽  
Cloud Formation ◽  
Melting Point Depression ◽  
Wide Range

Abstract Atmospheric aerosols can assume liquid, amorphous semi-solid or glassy, and crystalline phase states. Particle phase state plays a critical role in understanding and predicting aerosol impacts on human health, visibility, cloud formation, and climate. Melting point depression increases with decreasing particle diameter and is predicted by the Gibbs–Thompson relationship. This work reviews existing data on the melting point depression to constrain a simple parameterization of the process. The parameter $$\xi $$ ξ describes the degree to which particle size lowers the melting point and is found to vary between 300 and 1800 K nm for a wide range of particle compositions. The parameterization is used together with existing frameworks for modeling the temperature and RH dependence of viscosity to predict the influence of particle size on the glass transition temperature and viscosity of secondary organic aerosol formed from the oxidation of $$\alpha $$ α -pinene. Literature data are broadly consistent with the predictions. The model predicts a sharp decrease in viscosity for particles less than 100 nm in diameter. It is computationally efficient and suitable for inclusion in models to evaluate the potential influence of the phase change on atmospheric processes. New experimental data of the size-dependence of particle viscosity for atmospheric aerosol mimics are needed to thoroughly validate the predictions.

A study on the progress of mutarotation above and below the Tg and the relationship between constant rates and structural relaxation times

2017 ◽  
Vol 19 (31) ◽  
pp. 20949-20958 ◽  
Author(s):  
K. Wolnica ◽  
M. Dulski ◽  
E. Kaminska ◽  
A. Cecotka ◽  
M. Tarnacka ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Structural Relaxation ◽  
Relaxation Times ◽  
Ftir Studies ◽  
Wide Range ◽  
The Relationship

Comprehensive FTIR studies on the progress of mutarotation in d-fructose mixed with maltitol have been carried out over a wide range of temperatures, both above and below the glass transition temperature Tg.

scholarly journals Glass transition temperature and elastic modulusof nanocomposites based on polyimides

Vestnik MGSU ◽  
2015 ◽  
pp. 50-63
Author(s):  
Tat’yana Anatol’evna Matseevich ◽  
Marina Nikolaevna Popova ◽  
Andrey Aleksandrovich Askadskiy
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Elastic Modulus ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Chemical Structure ◽  
Van Der Waals Volume ◽  
Polar Groups ◽  
Wide Range ◽  
Nanoparticles Concentration

Today great attention is paid to production and research of the mechanical and termal properties of nanocomposites based on polyimides. These polymers are heatresisting and possess the increased mechanical properties in wide range of temperatures. Various nanoparticles are introduced into polyimides: graphite nanotubes and flatparticles, the particles of SiO , the surface of which is modified, the particles of ZrOandmontmorillonite, etc.The authors analyzed the influence of nanoparticles on the glass transition temper-ature T and elastic modulus E of the polyimides based on 1,3-bis-(3,3’,4,4’-dicarboxy-phenoxy)benzene and 4,4’-bis-(4-aminophenoxy)biphenyl, and pyromellitic dianhydride and oxydianiline. Nanoparticles introduced in small amounts are produced of graphite and ZrO . The suggested ratios take into account the chemical structure of the polymer and nanoparticles, as well as the structure of their surface in case of chemical modification; the concentration of nanoparticles and their form, the number of polar groups on the surface. The number of polar groups and nanoparticles’ concentration have the greatest influence on T . The elastic modulus of nanocomposites depending on nanoparticles’ concentration is connected with van der Waals volume of the repeating unit of polymer and nanoparticle.

scholarly journals On the Possibility of Indirect Determination of the Glass Transition Temperature of Proteins from Viscosity Measurements and Avramov's Model

2015 ◽  
Vol 37 (1) ◽  
pp. 63-70
Author(s):  
Karol Monkos
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Egg White ◽  
Hen Egg White Lysozyme ◽  
Indirect Determination ◽  
Egg White Lysozyme ◽  
Wide Range ◽  
Hen Egg White ◽  
Hen Egg

The paper presents the results of viscosity determinations on aqueous solutions of hen egg-white lysozyme, bovine ß-lactoglobulin, human and porcine immunoglobulin IgG at a wide range of concentrations and at temperatures ranging from 5oC to 55oC. Viscosity-temperature dependence of the proteins solutions is analyzed based on a formula resulting from the Avramov's model. One of the parameters in the Avramov's equation is the glass transition temperature Tg. It turns out that for all studied proteins, the Tg of the solution increases with increasing concentration. To determine the glass transition temperature of the dry protein Tg,p, a modified form of the Gordon-Taylor equation is used. This equation gives the relationship between Tg and the concentration of the solution, and Tg,p and a parameter dependent on the strength of protein-solvent interaction are fitting parameters. Thus determined the glass transition temperature for the studied dry proteins is in the range from 227.3 K (for bovine ß-lactoglobulin) to 260.6 K (for hen egg-white lysozyme).

scholarly journals Reduced Glass-Transition Temperature versus Glass-Forming Ability in FeCoB-Based Amorphous Alloys

2016 ◽  
Vol 61 (4) ◽  
pp. 1957-1962 ◽  
Author(s):  
M. Nabiałek
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glass Forming Ability ◽  
Scanning Calorimetry ◽  
Dsc Studies ◽  
Glass Forming ◽  
Wide Range ◽  
Temperature Ranges ◽  
The Relationship

AbstractThis work presents studies concerning the relationship between reduction of glass transition temperatureTrgand the glass-forming ability of FeCoB-based alloys. On the basis of theoretical considerations, Turnbull [1] determined the reduced glass transition temperature (Tg/Tl) as being 2/3 of the Vogel–Fulcher–Tammann (VFT) temperature; since then, continuous research has been carried out, aiming to calculate the Trg parameter and describe its relationship with glass-forming ability. In the majority of research papers, the reduced glass transition temperature is calculated from the relationshipTg/Tm, proposed by Uhlmann and Davies [2, 3]. On the basis of differential scanning calorimetry (DSC) studies, undertaken in this current work, the values of the following temperatures have been found:Tg,Tx, Tmand Tl, in addition to the temperature ranges:ΔTx,ΔTmandΔTl. The correlation between:Tg/Tm,Tg/Tland the glass-forming ability also has been discussed. Finally, for the investigated alloys, it has been found that the relationship proposed by Turnbull is reliable over a wide range ofΔTm.

scholarly journals Calculation of thermal expansion, glass transition temperature and glass density in the system RO–Al2O3–B2O3–SiO2 (where RO=BaO, SrO, CaO, MgO, ZnO)

2020 ◽  
pp. 69-74
Author(s):  
E.V. Karasik ◽  
◽  
Yu.S. Hordieiev ◽  
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Mathematical Models ◽  
Temperature Coefficient ◽  
Linear Expansion ◽  
Experimental Sample ◽  
Wide Range ◽  
Coefficient Of Linear Expansion

Glasses of the system RO–Al2O3–B2O3–SiO2 are used as a base for the fabrication of heat-resistant nonmetallic materials and general-purpose products. The purpose of this work is to develop mathematical models for calculating the temperature coefficient of linear expansion, glass transition temperature and density as a function of the composition of glass in the oxide system RO–Al2O3–B2O3–SiO2 where RO=BaO, SrO, CaO, MgO, ZnO. The disadvantage of the known models is that the range of their application is limited by the quantitative content of components in the glass. At the same time, an increase in the sample size of experimental compositions made it possible to obtain more accurate mathematical models for calculating these properties. The glasses included in the experimental sample are distinguished by a wide range of temperature coefficient of linear expansion (from 30 to 10510–7 К–1). The glass transition temperature of these glasses is within the range of 580–7100C, which allows a reasonable approach to the choice of temperature regime for the formation of the structure vitreous and glass-ceramic materials for different functional purposes. The mathematical models were developed with the use of the experimental and statistical method. The obtained mathematical models are adequate to the experimental data and allow calculating the thermal expansion, glass transition temperature and density of glasses; the mean-square deviations of temperature coefficient of linear expansion, glass transition temperature and density being 1.910–7 К–1, 16.00C and 0.06 g cm–3, respectively. Their accuracy is sufficient for the development of basic glass compositions for various functional purposes.

scholarly journals Viscoelastic properties of hydroxyl-terminated poly(butadiene) based composite rocket propellants

2014 ◽  
Vol 68 (4) ◽  
pp. 435-443 ◽  
Author(s):  
Sasa Brzic ◽  
Ljiljana Jelisavac ◽  
Jela Galovic ◽  
Danica Simic ◽  
Jelena Petkovic
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Free Volume ◽  
Loss Modulus ◽  
Mechanical Analysis ◽  
Thermal Coefficient ◽  
Fractional Free Volume ◽  
Rocket Propellants ◽  
Wide Range

In the present study, the viscoelastic response of three composite solid propellants based on hydroxyl-terminated poly(butadiene), ammonium perchlorate and aluminum has been investigated. The investigation was surveyed by dynamic mechanical analysis over a wide range of temperatures and frequencies. The mechanical properties of these materials are related to the macromolecular structure of the binder as well as to the content and nature of solid fillers. The storage modulus, loss modulus, loss factor and glass transition temperature for each propellant sample have been evaluated. The master curves of storage (log G' vs log ?) and loss modulus (log G'' vs log ?) were generated for each propellant. A comparison of logaT vs temperature curves for all propellants indicate conformance to Williams-Landel-Ferry equation. Choosing the glass transition as the reference temperature, WLF equation constants are determined. Fractional free volume at the glass transition temperature and thermal coefficient of free volume expansion values are in accordance with the consideration that Al is reinforcing filler.

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