Optical characteristics of a two-cylinder electrostatic lens

1946 ◽  
Vol 42 (2) ◽  
pp. 106-126 ◽  
Author(s):  
L. S. Goddard
Keyword(s):  
Experimental Determination ◽  
Theoretical Study ◽  
Optical Devices ◽  
Experimental Results ◽  
Optical Characteristics ◽  
Electrostatic Lens ◽  
Precise Formulation ◽  
The Subject ◽  
The Relationship

In this paper formulae are developed for the first and second focal lengths, and the positions of the first and second principal planes of a type of electrostatic lens which has been the subject of study (mostly experimental) in several previous papers. The lens, which is commonly used in electron optical devices, lends itself to a theoretical study, although this does not appear to have been attempted before. It consists of two equal semi-infinite cylinders placed end to end so that their axes coincide and the ends are separated by a small gap. If the cylinders are at potentials V1 and V2 and we write σ = V2/V1, the system behaves as an electron lens when σ > 0 and as an electron mirror when σ < 0. In the latter case some experimental results have been given by Nicoll(1) who also studied the focusing action in the case σ > 0 and, in particular, the formation of intermediate images when σ ≪ 1 and when σ ≫ 1. But for the precise formulation of the relationship between σ and the number of cross-overs a theoretical study, based on the paraxial equation, would be necessary. The problem will be indicated below. An experimental determination of the lens characteristics for values of σ from about 2 to 15 and for several gap widths has been made by Spangenberg(2), whose results will be compared with those obtained in the present paper. The two-cylinder lens has also been studied by Klemperer and Wright(3) using an experimental and a numerical (trigonometrical) method, and some crude analytical results have been given by Gray(4).

scholarly journals III. An experimental determination of the variation with temperature of the critical velocity of flow of water in pipes

1903 ◽  
Vol 201 (331-345) ◽  
pp. 45-61 ◽  
Keyword(s):  
Experimental Determination ◽  
Critical Velocity ◽  
Experimental Results ◽  
Experimental Side ◽  
The Subject ◽  
Theory And Experiment

The motion of water in pipes and channels has been the subject of frequent investigation, both from the theoretical and the experimental side, and it is well known that while in some cases theory and experiment are in exact accord, yet in many others the experimental results differ widely from the calculated. In some cases, while the theory holds for one set of conditions, it is found not to hold for conditions which at first do not appear to be fundamentally different.

An Experimental Determination of the Relationship between Lift and Aerodynamic Power in Calliphora Erythrocephala and Phormia Regina

1972 ◽  
Vol 56 (1) ◽  
pp. 31-36
Author(s):  
JAMES WOOD
Keyword(s):  
Steady State ◽  
Experimental Determination ◽  
Insect Flight ◽  
Phormia Regina ◽  
Calliphora Erythrocephala ◽  
The Relationship

Lift and aerodynamic power were calculated for Calliphora and Phormia using assumptions which maximized and minimized the ratio of aerodynamic power to lift. The ratios of aerodynamic power to lift calculated by these methods, which do not rely on the assumption that steady-state aerodynamics applies to insect flight, are in agreement with results calculated by others using steady-state aerodynamics.

scholarly journals Experimental Determination of the Buckling Loads of Floating Ice Sheets

1983 ◽  
Vol 4 ◽  
pp. 260-265 ◽  
Author(s):  
D. S. Sodhi ◽  
F. D. Haynes ◽  
K. Kato ◽  
K. Hirayama
Keyword(s):  
Experimental Data ◽  
Boundary Conditions ◽  
Experimental Determination ◽  
Characteristic Length ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Experimental Results ◽  
Buckling Loads ◽  
Data Points

Experiments were performed to determine the forces required to buckle a floating ice sheet pushing against structures of different widths. The characteristic length of each ice sheet was determined to enable a comparison to be made between the theoretical and experimental results.Most of the experimental data points are within the range of the theoretical values of normalized buckling loads for frictionless and hinged boundary conditions, which represent the extreme situations for ice-structure contact. Thus, the agreement between the theoretical and experimental buckling loads is considered to be good. Photographs of the buckled ice sheets show a resemblance to the theoretical mode of buckling.

scholarly journals Experimental Determination of the Buckling Loads of Floating Ice Sheets

1983 ◽  
Vol 4 ◽  
pp. 260-265 ◽  
Author(s):  
D. S. Sodhi ◽  
F. D. Haynes ◽  
K. Kato ◽  
K. Hirayama
Keyword(s):  
Experimental Data ◽  
Boundary Conditions ◽  
Experimental Determination ◽  
Characteristic Length ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Experimental Results ◽  
Buckling Loads ◽  
Data Points

Experiments were performed to determine the forces required to buckle a floating ice sheet pushing against structures of different widths. The characteristic length of each ice sheet was determined to enable a comparison to be made between the theoretical and experimental results. Most of the experimental data points are within the range of the theoretical values of normalized buckling loads for frictionless and hinged boundary conditions, which represent the extreme situations for ice-structure contact. Thus, the agreement between the theoretical and experimental buckling loads is considered to be good. Photographs of the buckled ice sheets show a resemblance to the theoretical mode of buckling.

scholarly journals Experimental Determination of Fatigue Life of Automotive Jounce Bumper

2011 ◽  
Vol 462-463 ◽  
pp. 634-638 ◽  
Author(s):  
R.S. Sidhu ◽  
Aidy Ali ◽  
M.R. Hassan
Keyword(s):  
Fatigue Life ◽  
Experimental Determination ◽  
Automotive Industry ◽  
Compressive Load ◽  
Experimental Results ◽  
Controlled Environment ◽  
Safety And Reliability ◽  
Repetitive Loading

It is evident that most rubber components in the automotive industry are subjected to repetitive loading. Vigorous research is needed towards improving the safety and reliability of the components. The study is conducted on an automotive rubber jounce bumper with a rubber hardness of 60 IRHD. The test is conducted in displacement controlled environment under compressive load. The existing models by Kim, Harbour, Woo and Li are adopted to predict the fatigue life. The experimental results show strong similarities with the predicted models.

Experimental Determination of the Ultimate Strength of Box Girder Specimens

2016 ◽  
Author(s):  
Thomas Lindemann ◽  
Patrick Kaeding ◽  
Eldor Backhaus
Keyword(s):  
Finite Element ◽  
Experimental Determination ◽  
Ultimate Strength ◽  
Progressive Collapse ◽  
Bending Moment ◽  
Element Model ◽  
Experimental Results ◽  
Bending Test ◽  
Box Girder

The Finite Element Method (FEM) is a feasible tool to perform progressive collapse analyses of large structural systems. Despite enormous developments in finite element formulations and computer technologies the results of structural analyses should be validated against experimental results. In this paper the collapse behaviour of two identical box girder specimens is determined experimentally for the load case of pure longitudinal bending. The specimens are composed of stiffened plate panels and connected at either ends to a loading structure. Within a 4-point bending test a constant bending moment is applied to each specimen to determine the collapse behaviour even in the post-ultimate strength range. The results of the experimental determination of the ultimate strength are presented for the box girder specimens. To simulate the collapse behaviour a finite element model is used and validated against experimental results.

scholarly journals The determination of fatigue limits under alternating stress conditions

1914 ◽  
Vol 90 (620) ◽  
pp. 411-425 ◽  
Keyword(s):  
Infinite Number ◽  
Fatigue Tests ◽  
Test Results ◽  
Railway Company ◽  
Standard Of Comparison ◽  
The Subject ◽  
Pull Tests ◽  
Push And Pull ◽  
The Relationship

In the year 1867 A. Wöhler, locomotive superintendent of a railway company in Berlin, exhibited at the Paris Exhibition the results of some experiments on the endurance of metals, and was thereupon engaged by the Prussian Government to carry out the more exhaustive enquiry into this subject with which his name is always associated. The results of his labours were published in 1871, and were highly appreciated, but few additional experiments were made until the subject was again taken up successively by Sir Benjamin Baker, Reynolds and Smith, Rogers, Stanton and bairstow, Eden, Rose and Cunningham, and Prof. Hopkinson. All these experiments are confined either to fatigue bending or to push and pull tests, using only steel or iron, whereas the present ones include a large number of torsion fatigue tests on various metals. Until comparatively recently there was no satisfactory standard of comparison for fatigue tests, the determination of the asymptote or limiting fatigue stress for an infinite number of revolutions from a few irregular test results leading to very uncertain conclusions, so much so that by some it was considered very doubtful whether there were any real fatigue limits, while others adopted as standards of comparison the fatigue stresses which would cause fractures at the millionth repetition. The first problem which had to be investigated was therefore to ascertain the relationship between the intensities of fatigue stresses and the numbers of repetitions of these stresses which would cause fracture; and, should this relationship be found to indicate the existence of a limiting stress for an infinite number of revolutions, or more briefly of a fatigue limit, then the next step would have to be its exact determination.

Origin of the Magnetic Proximity Effect

2002 ◽  
Vol 746 ◽  
Author(s):  
Miguel Kiwi
Keyword(s):  
Proximity Effect ◽  
Experimental Results ◽  
Metal Insulator ◽  
Theoretical Approaches ◽  
Metal Metal ◽  
The Subject ◽  
The Relationship ◽  
Magnetic Proximity Effect

ABSTRACTThe magnetic proximity effect (MPE) has attracted the attention of theorists and experimentalists for at least three decades. Lately, the relevance of the effect for the development of nanodevices has revived interest on the subject. Here we review how the field has evolved, centering our attention on metal-metal and metal-insulator systems. We describe, and critically compare, the different theoretical approaches that have been put forward, as well as their limitations. An evaluation of the relationship between existing theories and available experimental results is also attempted.

scholarly journals I. On the theory of lubrication and its application to Mr. Beauchamp tower’s experiments, including an experimental determination of the viscosity of olive oil

1886 ◽  
Vol 40 (242-245) ◽  
pp. 191-203 ◽  
Keyword(s):  
Olive Oil ◽  
Experimental Determination ◽  
Friction And Wear ◽  
Viscous Fluids ◽  
Solid Surfaces ◽  
Fundamental Importance ◽  
Theoretical Treatment ◽  
The Subject

Lubrication, or the action of oils and other viscous fluids to diminish friction and wear between solid surfaces, does not appear to have hitherto formed a subject for theoretical treatment. Such treatment may have been prevented by the obscurity of the physical actions involved, which belong to a class as yet but little known, namely, the boundary or surface actions of fluids; but the absence of such treatment has also been owing to the want of any general laws revealed by experiment. The subject is of such fundamental importance in practical mechanics, and the opportunities of observation so frequent, that it may well be a matter of surprise that any general laws should have for so long escaped detection.

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