PARA‐ AND DIAMAGNETIC SUSCEPTIBILITIES IN NON‐FLUCTUATING WEAK FIELDS

Geophysics ◽  
1958 ◽  
Vol 23 (4) ◽  
pp. 712-725
Author(s):  
William Schriever
Keyword(s):  
Torsion Balance ◽  
Solid Specimen ◽  
Bismuth Antimony ◽  
Absolute Measurements ◽  
Weak Fields ◽  
Micro Balance ◽  
Made In ◽  
Field Strengths

A Coulomb torsion balance apparatus was developed with which absolute measurements of para‐ and diamagnetic susceptibilities could be made in non‐fluctuating field strengths of the order of 1 oersted. Solid specimens of the diamagnetic elements, bismuth, antimony, and cadmium, were measured in fields of 2.5, 5, and 10 oersteds, and the para‐magnetic powders, [Formula: see text], [Formula: see text], and [Formula: see text], in fields of 2, 3, and 5 oersteds. The susceptibilities decreased with increasing field strengths. A specimen of bismuth granules had lower susceptibilities than did the solid specimen made from the same supply of granules. A semi‐micro balance apparatus also was constructed for absolute measurements in fields ranging between 100 and 1,000 oersteds. The susceptibilities of the diamagnetic specimens and a water specimen were measured. The solid bismuth, antimony, and cadmium specimens and a water specimen exhibited constant susceptibilities. The susceptibility of the bismuth‐granule specimen increased regularly from −4.67 to [Formula: see text] C.G.S. when the field increased from 100 to 900 oersteds. The value found for water [Formula: see text] agreed well with the International Critical Tables value [Formula: see text].

FAULTING IN THE BILLINGS OILFIELD, OKLAHOMA, AS INTERPRETED FROM TORSION BALANCE DATA, AND FROM SUBSEQUENT DRILLING

Geophysics ◽  
1943 ◽  
Vol 8 (4) ◽  
pp. 362-378
Author(s):  
H. Klaus
Keyword(s):  
Torsion Balance ◽  
Second Derivative ◽  
Oil Companies ◽  
Contour Maps ◽  
Made In

The results of an experimental torsion balance survey of the Billings Oilfield are shown by means of the conventional maps, and of second derivative contour maps. The latter show good and consistent anomalies, which are interpreted as faulting. The survey was made in July, 1937, some time after discovery of Ordovician production in the field, but long before faulting was clearly defined by drilling, and the results were communicated to several oil companies interested in the area or in the method of interpretation. In the meantime, one of the faults limiting the field has been defined in detail by drilling, and the present subsurface interpretation is compared with the original torsion balance predictions with respect to this fault. From the amount of agreement between the two sets of data, it is concluded that the torsion balance can still be used effectively for specialized purposes, particularly the investigation of faulting.

scholarly journals The Lower Limits of Perception of Electrical Currents by Fish

1931 ◽  
Vol 17 (2) ◽  
pp. 415-420 ◽  
Author(s):  
H. C. Regnart
Keyword(s):  
Current Density ◽  
Electrical Stimulus ◽  
Electric Currents ◽  
Electrical Field ◽  
Electrical Currents ◽  
Strong Fields ◽  
Lower Limits ◽  
Weak Fields ◽  
A Current ◽  
Made In

In recent years attention has been given to the influence of electrical currents as fish deflectors or screens, and experiments have been made to determine the magnitude of the currents which are sufficient to paralyse or act as deterrents to fish which may enter the electrical field, but in such strong fields the perception of the mechanism by which fish respond to electric currents is masked by the paralysis produced. It seemed possible that experiments with very weak currents might give fuller information concerning the mechanism by which fish respond to electrical stimulus than those made in strong fields. There is also the possibility that weak electric currents may occur in nature to which fish respond, but before exploring that field of phenomena it is necessary to observe the behaviour of fish under the influence of very weak fields. McMillan found that the field (volts per inch) required to paralyse young salmon varied with the resistivity of the water; thus when the latter was 10,000 ohms per inch cube the paralysing voltage was about 1·5, so that a current density of ampere per square inch was sufficient to cause paralysis, whereas when the resistivity was twelve ohms per inch cube the current required was ·03 ampere. In the former case the conductivity of the fish was greater than that of the water, in the latter case less.

scholarly journals The so-called thermoid effect and the question of superheating of a plantinum-silver resistance used in continuous-flow calorimetry

1912 ◽  
Vol 86 (587) ◽  
pp. 330-332 ◽  
Keyword(s):  
Specific Heat ◽  
Continuous Flow ◽  
High Speed ◽  
Electric Heating ◽  
Flow Calorimeter ◽  
Heating Current ◽  
Liquid Moving ◽  
Absolute Measurements ◽  
Good Agreement ◽  
Made In

In a recent paper by Glazebrook, Bousfield, and Smith some doubt has been east on the accuracy of my absolute measurements of the specific heat of water by the continuous-flow calorimeter. It is stated that an error of as much as 6 parts in 10,000 might have occurred in the superheating of the oil-stirred platinurn-silver resistances from which the values of the electric heating current were obtained. On the other band, it is also stated that this error might have been as small as 2.5 parts in 10,000. It was with some surprise that I read this statement, inasmuch as the authors could not have been aware of the rapidity of oil circulation which I used. It has been shown by Osborne Reynolds and others that the heat loss from a surface immersed in a liquid moving in turbulent motion is directly proportional to the velocity of flow. The degree of superheating of a wire immersed in oil will depend then directly on the rate of circulation, bully realising this fact, the resistances which I used were designed by Prof. Callendar and myself to be immersed in oil which could be circulated with great rapidity, These resistances are described in our papers, where the illustration shows approximately to scale the relative sizes of the stirrer and resistances. The paddle was rotated at a high speed by a powerful water motor, and the oil was thrown down with such force that a considerable depression was made in the surface. The oil, thrown sideways, passed up around the bars wires, which were wound loosely on the mica frames. I do not know by what standard Glazebrook, Bousfield, and Smith decide what is "normal stirring" or "very vigorous stirring," but it was evident to me at ones that I must have bad much more rapid circulation than anything used by these authors. In testing the accuracy of my experiments special attention was taken of possible superheating, and tests of stirring were made at the time. The good agreement of the various determinations of the specific heat, made with such different values for the heating current and flow of water, make evident that no large superheating error could have existed without being detected.

XLVI.—The Mechanics of Continuous Matter in the Relativity Theory

1949 ◽  
Vol 62 (4) ◽  
pp. 434-441 ◽  
Author(s):  
G. L. Clark
Keyword(s):  
Small Strain ◽  
Theory Of Elasticity ◽  
Relativity Theory ◽  
Fourth Power ◽  
Rotating Disc ◽  
Upper Limit ◽  
The Subject ◽  
The Waves ◽  
Weak Fields ◽  
Made In

SummaryLittle progress has been made in the development of a relativity theory of elasticity, although it has been realised that no disturbance can be propagated with a velocity greater than that of light. In 1917 Lorentz (1) gave a relativistic formulation of the laws of elasticity in the case of small strain and, applying the theory to the problem of a rotating, incompressible, homogeneous disc, he claimed that the radius as measured by an observer at rest on the disc undergoes a contraction. His result was accepted by Eddington (4) but was attacked by others. A great deal has been written on the subject, but it has never been pointed out that both Lorentz and Eddington were considering material in which the waves of dilatation travel with an infinite velocity. In this paper we define “incompressible” matter as that in which these waves are propagated with the velocity of light and Poisson's ratio tends to the value ½. This gives an upper limit to the modulus of compression k, which in this case is the elastic constant λ, and as a result the expansion determined by the ordinary classical theory has to be taken into account. It is found that the “relativity contraction” is exactly cancelled by the “classical expansion”. Throughout the discussion on the rotating disc the analysis is restricted to the case of small strain.The equations of equilibrium of a continuous static distribution of matter are also investigated in the case of weak fields for which the fourth power of the density may be neglected.

VIII. On a method of making a direct comparison of electrostatic with electromagnetice force; with a note on the electromagnetic theory of light

1868 ◽  
Vol 16 ◽  
pp. 449-450
Keyword(s):  
Electromagnetic Theory ◽  
Torsion Balance ◽  
The Other ◽  
Guard Ring ◽  
Micrometer Screw ◽  
Made In

The experiments described in this paper were made in the laboratory of Mr. Gassiot, who placed his great battery of 2600 cells of bichloride of mercury at the disposal of the author. Mr.Willoughby Smith lent his resistance-coils of 1,102,000 Ohms; Messrs. Forde and Fleeming Jenkin lent a sensitive galvanometer, a set of resistance-coils, a bridge, and a key for double simultaneous contacts; and Mr. C. Hockin undertook the observation of the galvanometer, the adjustment of the resistances, and the testing of the galvanometer, the resistance-coils, and the micrometer-screw, electrical balance itself was made by Mr. Becker. The experiments consisted in observing the equilibrium of two forces, one of which was the attraction between two disks, kept at a certain difference of potential, and the other was the repulsion between two circular coils, through which a certain current passed in opposite directions. For this purpose one of the disks, with one of the coils attached to its hinder surface, was suspended on one arm of a torsion-balance, disk, with the other coil behind it, was placed at a certain distance, which was measured by a micrometer-screw. The suspended disk, which was smaller than the fixed disk, was adjusted so that in its equilibrium its surface was in the same plane with that of a "guard-ring," as in Sir W. Thomson’s electrometers, and its position was observed by mean of a microscope directed on a graduated glass scale attached to the disk In this way its position could be adjusted to the thousandth of an inch while a motion of much smaller extent was easily detected.

Adsorption on measured surfaces of vitreous silica—II

1937 ◽  
Vol 160 (901) ◽  
pp. 254-267 ◽  
Keyword(s):  
Methyl Alcohol ◽  
Storage System ◽  
Vapour Phase ◽  
Vitreous Silica ◽  
Relative Pressure ◽  
Volatile Substances ◽  
Absolute Measurements ◽  
Made In

In earlier experiments (Part I Palmer 1935) a method of estimating the adsorption area of powdered silica was developed, and absolute measurements were obtained of the adsorption at 25° of a variety of volatile substances, but the relative pressure of the vapour phase was confined to a range below 0·5. An account is now given of similar measurements in which the pressure was taken to saturation with the typical substances benzene, acetone and methyl alcohol. Some modifications were made in the apparatus (shown in fig. 1 with lettering corresponding to Part I, fig. 1, p. 361) to cope with the larger adsorptions at higher pressures and the special difficulties in working with vapours near saturation. The superheating bulb C was immersed in water kept at 70-80° to ensure dryness in the vapour entering the storage bulbs B 1 and B 2 through the mercury trap a . The bulbs B 1 and B 2 were each of about 50 c. c. capacity and provided with capillary inlets k 1 and k 2 . The calibrated bulbs B 3 (total volume 40 c. c.) and the upper manometer point b 2 were added so that, by allowing mercury to flow from some or all of B 3 , pressure in the storage system could be lowered and read with b 2 without affecting the pressure in the adsorption tube A . This was especially necessary in experiments with methyl alcohol whose vapour shows very marked imperfection near saturation. A large air thermostat kept the whole apparatus at 25 ± 0·3°. As before, taps were completely excluded from the measuring parts of the apparatus.

scholarly journals On the extraction of electrons from cold conductors in intense electric fields

1928 ◽  
Vol 117 (778) ◽  
pp. 719-730 ◽  
Keyword(s):  
Continuous Function ◽  
Electric Fields ◽  
Applied Voltage ◽  
Thermionic Emission ◽  
Rapid Progress ◽  
Strong Fields ◽  
Wide Range ◽  
Firm Basis ◽  
Made In ◽  
Field Strengths

The discovery of this phenomenon seems to have evolved gradually from Earhart's* experiments on very short sparks in 1901. Since 1913 I have been familiar with the fact that in strong fields cold discharges could be made to pass in highly exhausted tubes under conditions which seemed to preclude the co-operation of gas as a factor. The phenomena appeared erratic and difficult to interpret. Recently, rapid progress has been made in the investigation of this effect especially owing to the researches of Gossling and of Millikan and Eyring, which have put it on a firm basis. Both Gossling and Millikan and Eyring have found, among other interesting facts, that with field strengths of the order of one million volts per cm. electrons can be drawn out of tungsten without the co-operation of gas, that the currents vary very rapidly with the applied voltage, and under proper conditions the current is reproducible and a continuous function of the applied voltage over a wide range, and that the currents at a given voltage are independent of the temperature provided the temperature is not so high as to approach the temperatures at which thermionic emission becomes appreciable.

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Magnetic-field strengths from optical polarization data

1967 ◽  
Vol 31 ◽  
pp. 381-383
Author(s):  
J. M. Greenberg
Keyword(s):  
Magnetic Field ◽  
Optical Polarization ◽  
Polarization Data ◽  
Term Model ◽  
Source Of Information ◽  
Field Strengths

Van de Hulst (Paper 64, Table 1) has marked optical polarization as a questionable or marginal source of information concerning magnetic field strengths. Rather than arguing about this–I should rate this method asq+-, or quarrelling about the term ‘model-sensitive results’, I wish to stress the historical point that as recently as two years ago there were still some who questioned that optical polarization was definitely due to magnetically-oriented interstellar particles.

Surface Structure in Microtomed Sections Caused by Glass and Diamond Knives

1971 ◽  
Vol 29 ◽  
pp. 456-457
Author(s):  
J. Temple Black ◽  
William G. Boldosser
Keyword(s):  
Plastic Deformation ◽  
Epoxy Resin ◽  
Carbon Coating ◽  
Surface Damage ◽  
Body Angle ◽  
Normal Manner ◽  
Bottom Side ◽  
Cutting Direction ◽  
Made In ◽  
Diamond Knife

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.

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