scholarly journals The interpretation of the results of Bucherer's experiments on e/m

1925 ◽  
Vol 107 (743) ◽  
pp. 544-560 ◽  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Parallel Plate ◽  
High Speed ◽  
Uniform Magnetic Field ◽  
Mechanical Force ◽  
High Potential ◽  
The Other ◽  
Uniform Electric Field ◽  
Left Handed

Introduction .—In the ‘Physikalische Zeitschrift,’ 9 Jahrgang, No. 22 pp. 755-760, and again, in greater detail, in the 'Annalen der Physik,’ 1909 vol. 28, pp. 513-536, Prof. A. H. Bueherer gives an account of an experiment performed by him with the object of ascertaining which of the various mass formulæ attributed to the electron by theoretical physicists agrees best with experiment. The method is briefly as follows: a source of high speed electrons (a stick of radium fluoride) is fixed on the axis of a circular parallel plate con denser, one of whose plates is connected to earth, and the other to a source o: high potential so as to produce a sensibly uniform electric field in the region between. Perpendicular to the electric field is applied a uniform magnetic field whose effect is to diminish, or increase, the mechanical force on the electron according as the direction of its velocity forms a left-handed or a right-handed system with those of the two fields. Since the distance between the plates is very small compared with their radius, it follows that the velocity of projection of an electron cannot have at arbitrary value if it is to escape from the condenser. Given the direction of projection of an electron, its velocity must lie between two definite limits which depend upon the relative intensities of the two fields, and also upon the distant between the plates of the condenser.

scholarly journals Elastic Properties of Magnetorheological Elastomers in a Heterogeneous Uniaxial Magnetic Field

2018 ◽  
Vol 19 (10) ◽  
pp. 3045 ◽  
Author(s):  
Takehito Kikuchi ◽  
Yusuke Kobayashi ◽  
Mika Kawai ◽  
Tetsu Mitsumata
Keyword(s):  
Magnetic Field ◽  
Elastic Properties ◽  
Uniform Magnetic Field ◽  
Large Strain ◽  
Small Strain ◽  
Experimental Results ◽  
The Other ◽  
Magnetorheological Elastomers ◽  
Other Hand ◽  
Strain Model

Magnetorheological elastomers (MREs) are stimulus-responsive soft materials that consist of polymeric matrices and magnetic particles. In this study, large-strain response of MREs with 5 vol % of carbonyl iron (CI) particles is experimentally characterized for two different conditions: (1) shear deformation in a uniform magnetic field; and (2), compression in a heterogeneous uniaxial magnetic field. For condition (1), dynamic viscoelastic measurements were performed using a rheometer with a rotor disc and an electric magnet that generated a uniform magnetic field on disc-like material samples. For condition (2), on the other hand, three permanent magnets with different surface flux densities were used to generate a heterogeneous uniaxial magnetic field under cylindrical material samples. The experimental results were mathematically modeled, and the relationship between them was investigated. We also used finite-element method (FEM) software to estimate the uniaxial distributions of the magnetic field in the analyzed MREs for condition (2), and developed mathematical models to describe these phenomena. By using these practicable techniques, we established a simple macroscale model of the elastic properties of MREs under simple compression. We estimated the elastic properties of MREs in the small-strain regime (neo–Hookean model) and in the large-strain regime (Mooney–Rivlin model). The small-strain model explains the experimental results for strains under 5%. On the other hand, the large-strain model explains the experimental results for strains above 10%.

scholarly journals Dielectrophoretic classification of fibres: principles and application to glass fibres suspended in air

2019 ◽  
Vol 213 ◽  
pp. 02053
Author(s):  
Frantisek Lizal ◽  
Milan Maly ◽  
Jakub Elcner ◽  
Arpad Farkas ◽  
Ondrej Pech ◽  
...  
Keyword(s):  
Electric Field ◽  
High Speed ◽  
Deposition Velocity ◽  
Uniform Electric Field ◽  
Electrical Mobility ◽  
Mobility Separation ◽  
Neutral Particles ◽  
Naturally Occurring ◽  
Two Parameters

Particles exposed to an electric field experience forces that influence their movement. This effect can be used for filtration of air, or for size classification of aerosols. The motion of charged particles in a non-uniform electric field is called electrophoresis. Two processes are involved in this phenomenon: 1) charging of particles and 2) electrical mobility separation. If fibres are exposed to electrophoresis, they are separated on the basis of two parameters: diameter and length. Regrettably, as naturally occurring fibres are polydisperse both in diameter and length, the electrophoresis is not very efficient in length classification. In contrast, dielectrophoresis is the motion of electrically neutral particles in a non-uniform electric field due to the induced charge separation within the particles. As deposition velocity of fibres induced by dielectrophoretic force strongly depends on length and only weakly on diameter, it can be used for efficient length classification. Principles of length classification of conducting and non-conducting fibres are presented together with design of a fibre classifier. Lastly, images of motion of fibres recorded by high-speed camera are depicted.

The bursting of soap-bubbles in a uniform electric field

1925 ◽  
Vol 22 (5) ◽  
pp. 728-730 ◽  
Author(s):  
C. T. R. Wilson ◽  
G. I. Taylor
Keyword(s):  
Electric Field ◽  
Water Drop ◽  
The Other ◽  
Uniform Electric Field ◽  
Geometrical Shape ◽  
Soap Bubble ◽  
Charged Drop ◽  
Mathematical Discussion ◽  
Mathematical Expressions ◽  
The Stability

The stability of a charged raindrop has been discussed mathematically by Lord Rayleigh. The case of an uncharged drop in a uniform electric field is perhaps of more meteorological importance but a mathematical discussion of the conditions for stability turns out to be very much more difficult in this case, owing to the fact that the drop ceases to be spherical before it bursts. Moreover it does not seem possible to express its geometrical shape by means of any simple mathematical expressions. On the other hand, by using a soap bubble instead of a water drop it was found possible to carry out experiments under well-defined conditions in this case, whereas experiments with Rayleigh's charged drop would be difficult.

Synergy Remediation of PBDEs Contaminated Soil by Electric-Magnetic Method

2013 ◽  
Vol 726-731 ◽  
pp. 2338-2341 ◽  
Author(s):  
Chun Du Wu ◽  
Yi Fan Yao ◽  
Qing Jie Xie
Keyword(s):  
Magnetic Field ◽  
Contaminated Soil ◽  
Polybrominated Diphenyl Ethers ◽  
Uniform Magnetic Field ◽  
Uniform Electric Field ◽  
Magnetic Method ◽  
Acid Base ◽  
Ph Values ◽  
Diphenyl Ethers ◽  
Soil Area

An electrokinetic and magnetic remediation system of polybrominated diphenyl ethers (PBDEs) contaminated soil was built in the laboratory. The characteristics of BDE15 migration under non-uniform electric field and uniform magnetic field were investigated. The results indicated that current and temperature in the soil reached the maximum values 100mA and 14°C respectively in 6h; the moisture content of soil near the cathode and anode was higher than in the middle position; pH values of soil increased gradually from the anode to the cathode and acid-base interface was in the soil area between 3cm from anode and 5 cm from anode; BDE15 mainly enriched in the area 5cm from the anode and reached 22.69μg·g-1.

Particle-Particle Interactions on the Surface of a Drop Subjected to a Uniform Electric Field

2008 ◽  
Author(s):  
S. Nudurupati ◽  
M. Janjua ◽  
P. Singh ◽  
N. Aubry
Keyword(s):  
Electric Field ◽  
Immiscible Liquid ◽  
The Other ◽  
Uniform Electric Field ◽  
Particle Interactions ◽  
Drop Surface ◽  
Dielectrophoretic Force ◽  
Dipole Interactions ◽  
Electric Field Direction ◽  
Local Direction

We recently proposed a technique in which an externally applied uniform electric field was used to alter the distribution of particles on the surface of a drop immersed in another immiscible liquid. Particles move along the drop surface to form a ring near the drop equator or collect at the poles depending on their dielectric constant relative to that of the two liquid involved. This motion is due to the dielectrophoretic force that acts upon particles because the electric field on the surface of the drop is non-uniform, despite the fact that the applied electric field is uniform. This technique could be useful to concentrate particles at a drop surface within well-defined regions (poles and equator), and separate two types of particles at the surface of a drop. In this paper we show that in addition to the dielectrophoretic force the particles also interact with each other via the dipole-dipole interactions to form chains or move away from each other depending the local direction of the electric field. The regions in which the local electric field is normal to the drop surface, i.e., the poles, the particles move away from each other. On the other hand, near the equator, where the local direction of electric field is tangential to the drops surface, they form chains that are aligned parallel to the electric field direction.

E.p.r. and endor of Tb 4+ in thoria

1965 ◽  
Vol 286 (1406) ◽  
pp. 352-365 ◽  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Field Gradient ◽  
Hyperfine Structure ◽  
Covalent Bonding ◽  
The Other ◽  
Nuclear Moment ◽  
Spin Hamiltonian ◽  
Crystalline Electric Field ◽  
A Value

E.p.r. and endor spectra have been measured in ThO 2 containing Tb 4+ . The crystalline electric field is cubic, and the splittings are very large compared with other S state ions. The values of the parameters in the standard cubic spin-Hamiltonian are: g = 2·0146 ±0·0004, 60 B 4 = —2527·53 ±0·10 Mc/s, 1260 B 6 = —24·84 ± 0·04 Mc/s, A = —73·891 ±0·023 Mc/s, B = + 6·194 ± 0·038 Mc/s, μN ( 159 Tb) = + 1·994 ± 0·004 nuclear magnetons. There are also additional small high-order terms. There are very marked differences between these parameters and those for the other S state ions Gd 3+ and Eu 2+ . In addition to the much larger 60 B 4 , the g value is in excess of the free spin value; at the nucleus, the electrons produce a smaller magnetic field (proportional to A / g 1 ) and a larger electric field gradient (proportional to B / Q ) than they do in Gd 3+ and Eu 2+ . These differences are probably due to covalent bonding. The value of the nuclear moment of 159 Tb has been used to obtain a value of <r -3 > = 8·23 a.u. for Tb 3+ from the known hyperfine structure in Tb 3+ .

On fluid motions induced by an electromagnetic field in a liquid drop immersed in a conducting fluid

1972 ◽  
Vol 51 (3) ◽  
pp. 585-591 ◽  
Author(s):  
C. Sozou
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Flow Field ◽  
Electric Field ◽  
Lorentz Force ◽  
Liquid Drop ◽  
Conducting Fluid ◽  
Uniform Electric Field ◽  
Tangential Electric Field ◽  
Set Up

The deformation of a liquid drop immersed in a conducting fluid by the imposition of a uniform electric field is investigated. The flow field set up is due to the surface charge and the tangential electric field stress over the surface of the drop, and the rotationality of the Lorentz force which is set up by the electric current and the associated magnetic field. It is shown that when the fluids are poor conductors and good dielectrics the effects of the Lorentz force are minimal and the flow field is due to the stresses of the electric field tangential to the surface of the drop, in agreement with other authors. When, however, the fluids are highly conducting and poor dielectrics the effects of the Lorentz force may be predominant, especially for larger drops.

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