The effects of pressure on the density, dielectric constant, and viscosity of several hydrocarbons and other organic liquids

1969 ◽  
Vol 47 (6) ◽  
pp. 893-899 ◽  
Author(s):  
D. W. Brazier ◽  
G. R. Freeman
Keyword(s):  
Molecular Structure ◽  
Dielectric Constant ◽  
Carbon Tetrachloride ◽  
Pressure Range ◽  
High Pressures ◽  
Liquid Structure ◽  
Dielectric Constants ◽  
Pressure Effects ◽  
Organic Liquids ◽  
Increasing Temperature

The effects of pressures up to 4 kbar on the density, dielectric constant, and viscosity of n-pentane, n-hexane, n-octane, cyclopentane, methylcyclohexane, and 2,2-dimethylbutane (DMB) were measured at 30 °C. The pressure effects on the viscosities of n-hexane and n-octane were also determined at 0 and 60°. The densities of diethyl ether and cyclopentanone and the dielectric constant of carbon tetrachloride at high pressures are also recorded. The densities of the hydrocarbons increased by 20–30% and the dielectric constants increased by 11–16% as the pressure was increased from 1 to 4000 bars at 30°, but the viscosities increased by 695–2352% over the same pressure range. Carbon tetrachloride froze at 1500 bars at 30°, and cyclopentanone froze at 3500 bars at about 20°. In agreement with earlier work on other liquids, the value of the Clausius–Mosotti function (ε − 1)V/(ε + 2) for the present compounds decreased slightly with increasing pressure. The viscosity at a given pressure decreased slightly with increasing temperature, and temperature effect increased with increasing pressure. In general, the smaller the compressibility of the liquid, the greater was the effect of pressure on the viscosity; DMB was an exception because its viscosity increased abnormally rapidly with pressure. Molecular structure and liquid structure have greater influences on the pressure dependence of viscosity than on that of density or dielectric constant.

Dielectric Properties of Blackberries as Related to Microwave Drying Control

2017 ◽  
Vol 13 (12) ◽  
Author(s):  
Chunfang Song ◽  
Tian Sang ◽  
Haiying Chen ◽  
Li Zhenfeng ◽  
Li Jing
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Moisture Content ◽  
Penetration Depth ◽  
Loss Factor ◽  
Large Scale ◽  
Coaxial Line ◽  
Dielectric Constants ◽  
Microwave Drying ◽  
Increasing Temperature

AbstractThe dielectric properties of blackberry samples with a 20.0–80.0 % w.b (web basis) moisture content were determined with a network analyzer and an open-ended coaxial-line probe over a frequency range from 5 to 3000 MHz and a temperature range from 20 to 100 °C. The results showed that the dielectric constant decreased with increasing temperature but increased with increasing moisture content; however, the loss factor increased with increasing temperature and moisture content. The dielectric constant and the loss factor decreased with increasing frequency. The penetration depth decreased with increasing temperature, frequency and moisture content. A large penetration depth at 915 MHz may provide practical large-scale dielectric drying for blackberries. The dielectric constants and loss factors for blackberry by combining the above mathematical model and temperature and moisture of the sample in the microwave drying process were used to analyze and control blackberry drying technology.

Devitrification and dielectric properties of (Na2O,BaO)–Nb2O5–SiO2 and (K2O,SrO)–Nb2O5–SiO2 glass–ceramics

2007 ◽  
Vol 22 (7) ◽  
pp. 1996-2003 ◽  
Author(s):  
Fei Peng ◽  
Robert F. Speyer ◽  
Wesley Hackenberger
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Alkaline Earth ◽  
Amorphous Matrix ◽  
Glass Ceramics ◽  
Dielectric Constants ◽  
Sio2 Glass ◽  
Increasing Temperature

(Na2O,BaO)–Nb2O5–SiO2 and (K2O,SrO)–Nb2O5–SiO2 glass ribbons with varying proportions of alkali and alkaline earth were formed using roller quenching. (Na2O,BaO)–Nb2O5–SiO2 glasses of compositions devitrified to form Ba2NaNb5O15 (in the form of ∼80 nm crystallites in an amorphous matrix) yielded frequency-stable dielectric constants of ∼250 and losses of ∼0.05. Such low losses and frequency stabilities were also observed from (K2O,SrO)–Nb2O5–SiO2 glasses of compositions forming predominantly KSr2Nb5O6 (∼30 nm crystals), yielding dielectric constants of ∼400. Both optimized compositions showed moderate decreases in dielectric constant with increasing temperature.

Compression of CCl4 at High Pressures

1983 ◽  
Vol 22 ◽  
Author(s):  
Sharrill D. Wood ◽  
Vern E. Bean
Keyword(s):  
Carbon Tetrachloride ◽  
Phase Change ◽  
Pressure Range ◽  
High Pressures ◽  
Rhombohedral Phase ◽  
Face Centered Cubic ◽  
Volume Changes ◽  
Capacitance Bridge ◽  
Face Centered ◽  
Fcc Phase

ABSTRACTThe compression of carbon tetrachloride has been measured along twelve isotherms covering a pressure range of 0.1 to 200 MPa and a temperature range of 254 to 298 K. Volume changes were measured with an automated capacitance bridge–one side of the bellows containing the sample serving as one plate of the capacitor. Data were obtained in the liquid, face-centered cubic (fcc), and rhombohedral phases, during melting, during freezing into the fcc phase and during the fcc to rhombohedral phase change. Premelting behavior was observed for both solids. The disappearance of the fcc phase at approximately 273 K and the existence of dual melting curves for the fcc and rhombohedral phases were reaffirmed.

Chemical Bonding of Fluorine Atoms in Siof Alloys: Microscopic Mechanisms for Reductions in the Dielectric Constant Relative to SiO2

1996 ◽  
Vol 443 ◽  
Author(s):  
G. Lucovsky ◽  
H. Yang
Keyword(s):  
Molecular Structure ◽  
Dielectric Constant ◽  
Ab Initio Calculations ◽  
Infrared Absorption ◽  
Chemical Bonding ◽  
Dielectric Constants ◽  
Low Concentrations ◽  
Inductive Effects ◽  
Infrared Absorption Spectra ◽  
Static Dielectric Constants

AbstractSi-O-F alloys have static dielectric constants (εs) significantly lower than SiO2. Infrared absorption spectra provide the basis modeling the molecular structure of these alloys. Contributions of electronic and vibrational transitions to εs are discussed in terms of an empirical chemical bonding model. Ab initio calculations are then used to identify inductive effects of Si- F bonds on the properties of Si-O-Si groups that are back-bonded to the Si atom of the Si-F group. These calculations provide a theoretical framework for understanding how relatively low concentrations of F atoms produce the significant decreases in εs reported for Si-O-F alloys.

scholarly journals The variation of the dielectric constants of some organic liquids with frequency in the range 1 to 10 3 Kilocycles

1930 ◽  
Vol 126 (801) ◽  
pp. 213-230 ◽  
Keyword(s):  
Dielectric Constant ◽  
Extreme Values ◽  
Dielectric Constants ◽  
Organic Liquids ◽  
Frequency Range ◽  
Absolute Value ◽  
The Subject ◽  
The Mean ◽  
Made In

Whilst it is recognised that the dielectric constant of liquids changes in the frequency range 10 4 - 10 5 kilocycles per second in accordance with the theory of Debye, no systematic examination of the variation of the dielectric constant of simple liquids with frequency appears to have been made at frequencies below 10 3 kc. per second. Exception must be made of the work of Fricke* who showed that the dielectric constant of blood did not change in the range 0­­­­.8 to 4500 kc., and of that of Bryan who recorded no change in the constant for xylene and an increase in the constant for nitrobenzene in the range 200 to1200 kc. In the case of chloroform and benzene a number of independent determinations have been made, eachat a fixed frequency. The values of the constants, however, at frequencies less than 1000kc. fluctuate considerably, for benzene the divergence between the extreme values is about 2­­·0 percent, of the mean, for chloroform about 12­­·5 percent. It is of importance, therefore, to establish whether these fluctuations are due to experimental error or the variation of the constant with frequency. The experiments now described were planned preliminary to work at higher frequencies; measurements of the dielectric constant and of the conductivity of a number of liquids have been made in the frequency range 1 to 10 3 kc. Attention has been directed to examine the variation of these quantities with frequency rather than to obtain­ing their absolute values. Owing to the illness of one of the authors the work had to be discontinued before the original programme had been completed, nevertheless, in view of the increasing importance of the subject the results appear to be of sufficient interest to merit publication. Since the data now reported were obtained, an extremely careful determination of the absolute value of the dielectric constant for benzene at 1000 cycles has been described by Hartshorn and Oliver ( loc. cit. ). They report no change in the constant in the audio frequency range, that is, presumably, below 5 kc., and thus confirm, in part, the data now presented.

Wide-range equations of state for organic liquids

2007 ◽  
Vol 5 ◽  
pp. 113-120 ◽  
Author(s):  
R.Kh. Bolotnova
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Organic Liquids ◽  
Liquid Phases ◽  
Wide Range ◽  
High Pressures And Temperatures

The method of construction the wide-range equations of state for organic liquids, describing the gas and liquid phases including dissociation and ionization which occurs during an intense collapse of steam bubbles and accompanied by ultra-high pressures and temperatures, is proposed.

scholarly journals Comment on “investigation of dielectric constants of water in a nano-confined pore” by H. Zhu, F. Yang, Y. Zhu, A. Li, W. He, J. Huang and G. Li, RSC Adv., 2020, 10, 8628

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 5179-5181
Author(s):  
Sayantan Mondal ◽  
Biman Bagchi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Constants ◽  
Static Dielectric Constant ◽  
Inherent Anisotropy ◽  
Nanoconfined Water

Neglects of inherent anisotropy and distinct dielectric boundaries may lead to completely erroneous results. We demonstrate that such mistakes can give rise to gross underestimation of the static dielectric constant of cylindrically nanoconfined water.

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