scholarly journals Investigating the quasi-oscillatory behavior of electrical parameters with the concentration of D-glucose in aqueous solution

2019 ◽  
Vol 6 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Subhadip Chakraborty ◽  
Chirantan Das ◽  
Rajib Saha ◽  
Avishek Das ◽  
Nirmal Kumar Bera ◽  
...  
Keyword(s):  
Random Distribution ◽  
Volume Fraction ◽  
Molecular Level ◽  
Oscillatory Behavior ◽  
Frequency Range ◽  
Electrical Parameters ◽  
Glucose Content ◽  
Polar Solution ◽  
Oscillatory Nature ◽  
Dipole Interactions

Abstract The impedance, capacitance and conductance of deionized water-glucose polar solution is measured by employing impedance spectroscopy and a quasi-oscillatory nature of variation with glucose content in the solution is observed. Such quasi-oscillatory nature is attributed to the randomly distributed water-water, water-glucose and glucose-glucose dipole interactions at the molecular level in the solution. A relevant analytical model is developed on the basis of such random distribution of the molecular dipoles and the experimental data agree well with those obtained from the theoretical model. The electrical parameters are measured in the frequency range of 100Hz to 4MHz for the volume fractions of glucose with respect to water in the range of 0.1 to 0.5. The impedance, capacitance and conductance are obtained to be in the range of 1.03 kΩ – 112 kΩ, 34.9 pF – 1.66 nF, and 8.95 μS – 52.9 μS respectively for the glucose volume fraction range considered.

Understanding Wet Skid Resistance Testing with the British Pendulum Skid Tester: Analysis of Sliding Noise from Various Filled Compounds

2010 ◽  
Vol 83 (1) ◽  
pp. 97-122 ◽  
Author(s):  
Xiao-Dong Pan ◽  
Paul Zakelj ◽  
Cara Adams ◽  
Akiko Neil ◽  
Greg Chaplin
Keyword(s):  
Volume Fraction ◽  
Concrete Surface ◽  
Resistance Testing ◽  
Styrene Butadiene Rubber ◽  
Skid Resistance ◽  
Butadiene Rubber ◽  
Portland Cement Concrete ◽  
Frequency Range ◽  
Rubber Compounds ◽  
Wet Skid Resistance

Abstract The British pendulum skid tester (BPST) has been widely adopted for laboratory characterization of wet skid resistance (WSR) for rubber compounds. However, testing results are not yet well explained with material properties. For filled compounds made of the same styrene-butadiene rubber, on a Portland cement concrete surface wetted with water, WSR for compounds filled with inorganic oxides is higher than WSR for compounds filled with carbon black at the same filler volume fraction. However, such difference in WSR is eliminated under ethanol lubrication. Difference in WSR remains under ethanol lubrication between compounds filled with a reinforcing filler and compounds filled with a nonreinforcing filler. Accepting that dynamic deformation of rubber occurs in the frequency range between 103 and 106 Hz during testing with the BPST, loss tangent for the compounds is measured at various low temperatures but fails to correlate with WSR detected under water lubrication. Modification of bulk viscoelasticity from ethanol absorption should not be neglected for consideration of WSR under ethanol lubrication. During testing with the BPST, sliding noise generated by the assemblage of the spring and lever system in the pendulum with a rubber slider attached is captured under varied lubrication conditions. Both viscoelastic properties of rubber compounds and lubrication condition significantly affect sliding noise. However, no strict correlation between the intensity of sliding noise and WSR is observed. From frequency domain analysis, major components of the sliding noise lie in the frequency range between 500 and 5000 Hz for most compounds. For better understanding on testing with the BPST, modes of material deformation during dynamic sliding on a wet rough surface need to be further scrutinized.

Conductivity of Normal and Pathological Human Erythrocytes (Homozygous β-Thalassemia) at Radiowave Frequencies

1984 ◽  
Vol 39 (1-2) ◽  
pp. 160-166 ◽  
Author(s):  
C. Ballario ◽  
A. Bonincontro ◽  
C. Cametti ◽  
A. Rosi ◽  
L. Sportelli
Keyword(s):  
Temperature Interval ◽  
Human Erythrocytes ◽  
Pathological State ◽  
Frequency Range ◽  
Electrical Parameters ◽  
Ellipsoidal Particles ◽  
Unit Surface

Abstract The conductivity of normal and homozygous β-thalassemic erythrocyte suspensions has been measured over the frequency range from 5 KHz to 100 MHz in the temperature interval from 5 to 45 °C. The electrical parameters of the membrane, i.e., the capacitance CM and the conductance GM per unit surface have been calculated from an expression given by Hanai for the conductivity of a suspension of ellipsoidal particles covered with a shell. Some interesting differences between the normal and pathological state are evidentiated.

Can the Strength of Brittle Materials be Enhanced?

1992 ◽  
Vol 291 ◽  
Author(s):  
L. Monette ◽  
M. P. Anderson ◽  
G. S. Grest
Keyword(s):  
Computer Model ◽  
Random Distribution ◽  
Load Transfer ◽  
Volume Fraction ◽  
Fiber Composites ◽  
Short Fiber ◽  
Particulate Composites ◽  
Second Phase ◽  
Two Dimensional ◽  
Fiber Volume

ABSTRACTWe have employed a two-dimensional computer model to study the effect of volume fraction of second phase constituents on load transfer (stiffness) and strength in brittle short-fiber composites, i.e. composites containing a random distribution of aligned fibers, and brittle particulate composites. We find that the efficiency of load transfer to the second phase consituent increases with volume fraction in particulate composites, while it decreases for short-fiber composites. The strength of brittle particulate composites is found to decrease, while the strength of brittle short-fiber composites marginally increases only at fiber volume fractions equal or greater than 0.25.

The spatial distribution of spheres falling in a viscous liquid

1968 ◽  
Vol 32 (1) ◽  
pp. 203-207 ◽  
Author(s):  
T. N. Smith
Keyword(s):  
Reynolds Number ◽  
Spatial Distribution ◽  
Viscous Liquid ◽  
Random Distribution ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Binomial Probability ◽  
Single Sphere

The spatial distribution of uniformly sized spheres falling in a viscous liquid is investigated experimentally for a solid volume fraction of 0·025 and a single sphere Reynolds number of 0·6. The observed spatial distribution agrees closely with a random distribution based on allocation of spheres to space cells according to a binomial probability mechanism.

scholarly journals Гибридный металлополимер как потенциальная активная среда оптоакустического генератора

2022 ◽  
Vol 48 (3) ◽  
pp. 36
Author(s):  
Е.И. Гиршова ◽  
Е.П. Микитчук ◽  
А.В. Белоновский ◽  
К.М. Морозов
Keyword(s):  
Silver Nanoparticles ◽  
Active Medium ◽  
Hybrid Material ◽  
Volume Fraction ◽  
Silver Content ◽  
Thermodynamic Characteristics ◽  
Operating Frequency ◽  
Frequency Range ◽  
Volume Fractions ◽  
Operating Frequency Range

A hybrid material was studied, consisting of polydimethylsiloxane and silver nanoparticles distributed throughout its volume, its optical and thermodynamic characteristics were calculated for different volume fractions of silver content. It is theoretically shown that this material with a volume fraction of silver of about 30% can be used as an active medium for an optoacoustic transducer with an operating frequency range of about 10 MHz.

scholarly journals Heat Transfer in Cassava Starch Biopolymers: Effect of the Addition of Borax

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4106
Author(s):  
Adriana Paola Franco-Bacca ◽  
Fernando Cervantes-Alvarez ◽  
Juan Daniel Macías ◽  
Joan Alexis Castro-Betancur ◽  
Reynell Junior Pérez-Blanco ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Food Packaging ◽  
Volume Fraction ◽  
Molecular Level ◽  
Cassava Starch ◽  
Effective Strategy ◽  
Interconnected Network ◽  
Packaging Industry ◽  
Heat Carriers

In recent years, polymer engineering, at the molecular level, has proven to be an effective strategy to modulate thermal conductivity. Polymers have great applicability in the food packaging industry, in which transparency, lightness, flexibility, and biodegradability are highly desirable characteristics. In this work, a possible manner to adjust the thermal conductivity in cassava starch biopolymer films is presented. Our approach is based on modifying the starch molecular structure through the addition of borax, which has been previously used as an intermolecular bond reinforcer. We found that the thermal conductivity increases linearly with borax content. This effect is related to the crosslinking effect that allows the principal biopolymer chains to be brought closer together, generating an improved interconnected network favoring heat transfer. The highest value of the thermal conductivity is reached at a volume fraction of 1.40% of borax added. Our analyses indicate that the heat transport improves as borax concentration increases, while for borax volume fractions above 1.40%, heat carriers scattering phenomena induce a decrement in thermal conductivity. Additionally, to obtain a deeper understanding of our results, structural, optical, and mechanical characterizations were also performed.

scholarly journals Dielectric Properties of Deep Ice Cores with Air-Hydrate Inclusions (Abstract)

1988 ◽  
Vol 10 ◽  
pp. 210
Author(s):  
Shinji Mae ◽  
Takeo Hondoh ◽  
Masayoshi Nakawo ◽  
C.C. Langway
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Dielectric Properties ◽  
Time Variation ◽  
Volume Fraction ◽  
Ice Cores ◽  
Frequency Range ◽  
Temperature Range ◽  
The Core

Air-hydrate inclusions have been found in deep ice cores from Dye 3, Greenland, which were taken in August 1981. Although the concentration of the air-hydrate crystals decreased with time, when the core was stored at a temperature of −50 °C, they still existed to an appreciable extent in 1985. An ice specimen was cut out from the Dye 3 core at a depth of 1500 m, where the volume fraction of the hydrate crystals was about 10−3 by volume. Its dielectric properties were measured in September 1985, in a frequency range of 30-20 × 103 Hz and temperature range of −20° to −90°C. The activation energy obtained for the relaxation time of the Debye dispersion was about 0.2 eV, which is much smaller than that of pure ice. The measurement was repeated once a month for about a year, and the sample was stored at a temperature of −10 °C between measurements. The time variation of the dielectric properties has been discussed in relation to the deterioration of the air-hydrate crystals.

Observations of high-frequency scattered waves using dense arrays at Teide Volcano

1997 ◽  
Vol 87 (6) ◽  
pp. 1637-1647
Author(s):  
E. Del Pezzo ◽  
M. La Rocca ◽  
J. Ibanez
Keyword(s):  
Random Distribution ◽  
Great Part ◽  
Apparent Velocity ◽  
Frequency Range ◽  
Small Aperture ◽  
Analysis Techniques ◽  
Correlated Arrivals ◽  
Seismic Coda ◽  
The Time Domain ◽  
Teide Volcano

Abstract A study of the seismic coda of seven small earthquakes recorded on the Teide Volcano-Canary Islands (Spain) was carried out using a temporary, small-aperture, 12-station, seismic array. The purpose was to measure backazimuth, apparent velocity and the type of waves that compose the coda in the frequency range 4 to 6 Hz. We used the zero-lag cross-correlation (ZLC) method to obtain the components of the wave vector and three-component analysis techniques based on the covariance matrix of the signal in the time domain to investigate the polarization properties of the signals. The results show that a great part of the coda signals in the analyzed frequency range are almost uncorrelated, while a low number of isolated correlated arrivals show an apparent slowness between 2 × 10−3 and 2.5 × 10−4 sec/m and an almost random distribution of backazimuths. The correlated arrivals have been interpreted as generated by strong scatterers, probably related to the presence, in the study area, of surface topography irregularities (the volcanic cone and the caldera rim). The wave type varies from pure S-type waves to mixed surface waves with some Rayleigh components.

Application of Broad-Band Dielectric Spectroscopy for Investigations of Liquid Crystal - Porous Media Microcomposites

1997 ◽  
Vol 500 ◽  
Author(s):  
G. P. Sinha ◽  
B. Batalla ◽  
F. M. Aliev
Keyword(s):  
Dielectric Properties ◽  
Dielectric Spectroscopy ◽  
Volume Fraction ◽  
Broad Band ◽  
Interfacial Polarization ◽  
Pore Wall ◽  
Slow Process ◽  
Frequency Range ◽  
Average Pore ◽  
Hindered Rotation

ABSTRACTWe applied ultra broad-band dielectric spectroscopy in the frequency range from 10–3 Hz to 109 Hz to investigate the effect of size, shape and volume fraction of the pores in the porous matrices on the dielectric properties of liquid crystals (LC) dispersed in these matrices. Measurements in such a broad frequency range make it possible to obtain detailed information on the important aspects of the electrical behavior of heterogeneous materials such as: conductivity, surface polarization, and influence of confinement on dynamics of molecular motion of polar molecules forming LC. We investigated alkylcyanobiphenyls in the isotropie, nematic and smectic phases dispersed in porous glasses (average pore sizes - 100 Å and 1000 Å) which have randomly oriented, interconnected pores, and anopore membranes (pore diameters - 200 Å and 2000 Å) with parallel cylindrical pores. Dispersion of LC resulted in qualitative changes of their dielectric properties. Analysis of broad-band dielectric spectra shows that in organic (LC) - inorganic (porous matrix) heterogeneous composites conductivity plays an important role at F <1 Hz. We observe the appearance of new dielectric modes: a very slow process with characteristic frequency ≃ (1 – 10) Hz and a second process in frequency range about (103 - 106) Hz. The slow process arises due to the relaxation of interfacial polarization at pore wall - LC interface. The origin of this could be due to absorption of ions at the interface. Another possibility is the preferential orientation of the permanent dipoles at pore surface. The second new mode is due to the hindered rotation of the molecules near the interface. Additionally we observed two bulk like modes due to the rotation of the molecules around their short and long axii which are modified.

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