The Hertzian Spectrum of Rubber and Its Micellar Constitution

1946 ◽  
Vol 19 (4) ◽  
pp. 1085-1087
Author(s):  
Pierre Girard ◽  
Paul Abadie
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Wave Length ◽  
Structural Features ◽  
Loss Angle ◽  
First Case ◽  
Dipolar Molecules ◽  
Alternating Electric Field ◽  
Different Types ◽  
Absorption And Dispersion

Abstract The spectra which were studied lie within the region of hertzian frequencies, and can be represented either by dispersion curves showing the dielectric constant of the substance as a function of the frequency (or wave length λ), or by absorption curves showing the loss angle as a function of this frequency. These two types of curves represent the same phenomenon, i.e., orientation of the dipolar molecules in the alternating electric field, in accordance with the theory of Debye. The spectra and their interpretation depend chiefly on whether the molecules are crystalloid with relatively small and similar dimensions, or are colloidal, with large and unequal dimensions. In the first case, the spectra gives evidence chiefly on the form of the molecules and their structural features. Dilution in a nonpolar solvent shows for certain dipolar compounds, e.g., alcohol, considerable deformations, which differ according to the solvent. In the case of colloids, e.g., rubber, which has a permanent moment, the spectra and the meaning of these spectra are far different. In this case the spectra indicate that the absorption and dispersion values in the hertzian region are closely related to the micellar constitution, i.e., to the different types of micelles, to their size, and to the proportion of each type.

scholarly journals Coexistence of Flexo- and Ferro-Electric Effects in an Ordered Assembly of BaTiO3 Nanocubes

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 188
Author(s):  
Kyuichi Yasui ◽  
Hiroki Itasaka ◽  
Ken-ichi Mimura ◽  
Kazumi Kato
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Frequency Dependence ◽  
Dielectric Response ◽  
The Other ◽  
Flexoelectric Effect ◽  
Alternating Electric Field ◽  
Ordered Assembly ◽  
Electric Effects ◽  
Theory And Experiments

It has been reported that the flexoelectric effect could be dominant in the nanoscale. The discrepancy between theory and experiments on the frequency dependence of the dielectric constant of an ordered assembly of BaTiO3 nanocubes is nearly resolved by assuming the coexistence of flexo- and ferro-electric effects. Although flexoelectric polarizations perpendicular to the applied alternating electric field contribute to the dielectric constant, those parallel to the electric field do not contribute because the magnitude of the flexoelectric polarization does not change due to the mismatch of strain at the interface of the nanocubes. On the other hand, some dielectric response is possible for the ferroelectric component of the polarization parallel to the electric field.

Alternating electric field fluidized bed disinfection performance with different types of granular activated carbon

2014 ◽  
Vol 132 ◽  
pp. 70-76 ◽  
Author(s):  
Justina Racyte ◽  
Doekle R. Yntema ◽  
Laura Kazlauskaite ◽  
Anne-Claire Dubois ◽  
Harry Bruning ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electric Field ◽  
Fluidized Bed ◽  
Granular Activated Carbon ◽  
Alternating Electric Field ◽  
Different Types

Removal of Particles From the Surface of a Droplet

2008 ◽  
Author(s):  
N. Aubry ◽  
P. Singh ◽  
S. Nudurupati ◽  
M. Janjua
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Strong Electric Field ◽  
Dielectric Constants ◽  
The Other ◽  
Uniform Electric Field ◽  
Drop Deformation ◽  
Ambient Fluid ◽  
Dielectrophoretic Force ◽  
Different Types

We present a technique to concentrate particles on the surface of a drop, separate different types of particles, and remove them from the drop by subjecting the drop to a uniform electric field. The particles are moved under the action of the dielectrophoretic force which arises due to the non-uniformity of the electric field on the surface of the drop. Experiments show that depending on the dielectric constants of the fluids and the particles, particles aggregate either near the poles or near the equator of the drop. When particles aggregate near the poles and the dielectric constant of the drop is greater than that of the ambient fluid, the drop deformation is larger than that of a clean drop. In this case, under a sufficiently strong electric field the drop develops conical ends and particles concentrated at the poles eject out by a tip streaming mechanism, thus leaving the drop free of particles. On the other hand, when particles aggregate near the equator, it is shown that the drop can be broken into three major droplets, with the middle droplet carrying all particles and the two larger sized droplets on the sides being free of particles. The method also allows us to separate particles for which the sign of the Clausius-Mossotti factor is different, making particles of one type aggregate at the poles and of the second type aggregate at the equator. The former are removed from the drop by increasing the electric field strength, leaving only the latter inside the drop.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Small-Angle Electron Scattering (SAES) of Polymers

1985 ◽  
Vol 43 ◽  
pp. 78-79
Author(s):  
Ralph Oralor ◽  
Pamela Lloyd ◽  
Satish Kumar ◽  
W. W. Adams
Keyword(s):  
Electron Scattering ◽  
Small Angle ◽  
Angular Resolution ◽  
Structural Features ◽  
Objective Lens ◽  
High Angular Resolution ◽  
Push Button ◽  
First Case ◽  
Diffraction Mode ◽  
Very High

Small angle electron scattering (SAES) has been used to study structural features of up to several thousand angstroms in polymers, as well as in metals. SAES may be done either in (a) long camera mode by switching off the objective lens current or in (b) selected area diffraction mode. In the first case very high camera lengths (up to 7Ø meters on JEOL 1Ø ØCX) and high angular resolution can be obtained, while in the second case smaller camera lengths (approximately up to 3.6 meters on JEOL 1Ø ØCX) and lower angular resolution is obtainable. We conducted our SAES studies on JEOL 1ØØCX which can be switched to either mode with a push button as a standard feature.

The Chemical Decontamination Process Intensification, using Ultrasounds

2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Eugenia Pantru ◽  
Gheorghit Jinescu ◽  
Rozalia R�dulescu ◽  
Antoneta Filcenco Olteanu ◽  
Cosmin Jinescu
Keyword(s):  
Chemical Composition ◽  
Process Intensification ◽  
Sulphuric Acid Solution ◽  
Liquid Ratio ◽  
Polluted Soils ◽  
Chemical Decontamination ◽  
First Case ◽  
Ultrasound Field ◽  
Different Types ◽  
Main Factors

This paper presents an intensive procedure used for the decontamination of the soils, which were radioactively contaminated by uranium, due to the occurrence of some antropic accidents, in order to limit the area�s pollution. The procedure used for the chemical decontamination of the polluted soils was the washing one and the decontamination degree is comparatively presented depending on the ultrasounds� presence and absence. The lab testes were performed on five types of soils , which were characterized from the granulometric, structural and chemical composition viewpoint, all these aspects represent the main factors, which determine the applied decontamination procedure�s limits and performances correlated with its utilization costs. The decontamination procedure�s kinetics for each type of soils was analyzed, using successively three different types of reagents (water, 0.1 M sulphuric acid solution and chloro-sodic solution � 100 g/L sodium chloride + 10 g/L sodium carbonate in water) for a solid to liquid ratio of 1:2, during 2 h, at a temperature of 20oC in a mechanic stirring system respectively in ultrasounds field. It was observed that the decontamination degree increases with up to 15-20% in case of the ultrasound field utilization comparing to the first case.

Formation of Regular Domain Structures in Quenched Ferroelectrics Under the Influence of an External High-frequency Electric Field

2019 ◽  
Vol 9 (3) ◽  
pp. 344-352 ◽  
Author(s):  
L.I. Stefanovich ◽  
O.Y. Mazur ◽  
V.V. Sobolev
Keyword(s):  
Lithium Niobate ◽  
Electric Field ◽  
Domain Structure ◽  
High Frequency ◽  
Evolution Equations ◽  
Regular Domain ◽  
Field Frequency ◽  
Domain Structures ◽  
Alternating Electric Field ◽  
Lithium Niobate Crystals

Introduction: Within the framework of the phenomenological theory of phase transitions of the second kind of Ginzburg-Landau, the kinetics of ordering of a rapidly quenched highly nonequilibrium domain structure is considered using the lithium tantalate and lithium niobate crystals as an example. Experimental: Using the statistical approach, evolution equations describing the formation of the domain structure under the influence of a high-frequency alternating electric field in the form of a standing wave were obtained. Numerical analysis has shown the possibility of forming thermodynamically stable mono- and polydomain structures. It turned out that the process of relaxation of the system to the state of thermodynamic equilibrium can proceed directly or with the formation of intermediate quasi-stationary polydomain asymmetric phases. Results: It is shown that the formation of Regular Domain Structures (RDS) is of a threshold character and occurs under the influence of an alternating electric field with an amplitude less than the critical value, whose value depends on the field frequency. The conditions for the formation of RDSs with a micrometer spatial scale were determined. Conclusion: As shown by numerical studies, the RDSs obtained retain their stability, i.e. do not disappear even after turning off the external electric field. Qualitative analysis using lithium niobate crystals as an example has shown the possibility of RDSs formation in high-frequency fields with small amplitude under resonance conditions

scholarly journals Controlled growth of ultrafine metal nanoparticles mediated by solid supports

2021 ◽  
Vol 3 (7) ◽  
pp. 1865-1886
Author(s):  
Hongyin Hu ◽  
Shuanglong Lu ◽  
Ting Li ◽  
Yue Zhang ◽  
Chenxi Guo ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Catalytic Properties ◽  
Structural Features ◽  
Controlled Growth ◽  
Solid Supports ◽  
Ultrafine Metal ◽  
Different Types

This article reviews the controlled growth of UMNPs mediated by different types of solid supports and their catalytic properties. The importance of certain structural features of the supports is also discussed.

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