bluuebunny/crossref_metadata_2025 huggingface dataset:
RHEOLOGY OF THE EARTH: THE BASIC PROBLEM OF GEODYNAMICS
Authors: Scheidegger A. E.
Published: April 2011

A discussion is given of the data which are available to provide information on the rheological behavior of the Earth's mantle and crust. It is shown that a fundamental distinction has to be made between stress durations that are "short" (up to 4 hours), "intermediate" (4 hours to 15,000 years), and "long" (longer than 15,000 years). For short durations, the behavior of the Earth is well known from the results of seismological investigations. However, these results should not be applied directly to the longer time durations. For intermediate time durations, the Earth shows an elastic aftereffect. One obtains a value for the (Kelvin) viscosity if it is assumed that the damping of the variation of latitude is caused by a Kelvin effect. The same (Kelvin) viscosity is arrived at if the strain rebound characteristics of earthquake aftershock sequences are also interpreted in terms of an elastic aftereffect. For stresses of long duration, some information may be obtained from the uplift of Fennoscandia. It appears that viscous creep is the prevailing phenomenon. If this information is combined with some further considerations, indications are that the Earth behaves like a Bingham body. Then, the fact that orogenetic phenomena are concentrated in narrow bands may be due to the existence of solutions of the Bingham equation exhibiting rheological instability.
VARIATIONS IN THE AMOUNTS OF POSITRONIUM FORMED IN LIQUIDS AND AMORPHOUS SOLIDS
Authors: Green R. E. , Bell R. E.
Published: April 2011

Measurements are reported of the intensity, I2, of the long-lived (τ2) component of positron annihilations in a number of liquids and amorphous solids. Large variations in I2 have been found with different samples of similar substances. It is shown, for example, that I2 for fused quartz of good quality is about 51% of all the positron decays, and that an earlier published value of 29% probably referred to a 96% silica glass rather than to pure fused quartz. The new value, taken with the results of angular correlation measurements, gives convincing evidence that the annihilation of triplet positronium in condensed materials proceeds mainly by the "pickoff" mechanism. It is shown that the addition of NO3− and NO2− ions to water in increasing concentration depresses I2 from its normal value of (21 ± 5)% to a value at least as low as 2% without any marked change in τ2. This behavior is explained in terms of the formation of the positron compound e+NO3− in the water. This hypothesis explains the shape of the curve of I2 as a function of NO3− ion concentration and also gives a cross section for the capture of positrons by NO3− in rough agreement with expectation.
SOME SCATTERING PROBLEMS IN CONDUCTION THEORY
Authors: Klemens P. G.
Published: April 2011

An expression is derived for the scattering of electrons by inhomogeneous strain fields in terms of the scattering of electrons by low frequency lattice vibrations, as deduced from the low temperature intrinsic thermal resistivity and the lattice thermal conductivity. This is applied to the scattering of electrons by dislocations and stacking faults. An expression for the scattering of lattice waves by stacking faults is also derived. The validity of these results is discussed.
ELECTRICAL RESISTIVITY OF GRAPHITE IRRADIATED WITH NEUTRONS
Authors: Attree R. W. , Dahlinger O.
Published: April 2011

Measurements have been made of the changes in the electrical resistance of an artificial graphite which are induced by neutron irradiation and subsequent annealing. The resistivity increases with irradiation; the increase in resistance is partially removed by annealing at 128 °C. These changes have been interpreted using Wallace's theory of the electron structure of graphite. The number of atoms displaced by the irradiation has been calculated using the method of Seitz, and is shown to be consistent with the experimental results.
ADIABATIC OSCILLATIONS IN LIQUID HELIUM II
Authors: Manchester F. D. , Brown J. B.
Published: April 2011

Oscillations have been observed in an experimental arrangement consisting of an adiabatic container placed in a helium II bath and connected with the bath by means of a "superleak". A "thermal pulse" introduced into the container caused the liquid level to oscillate. Containers of different geometries and employing two different types of superleak were successfully used to observe oscillations. With one of these the temperature dependence of the frequency was measured between 1.39° and 2.065°K. and found to be of the form and magnitude expected from the calculations of Robinson (1951). Other features of the oscillations have been investigated. An analogy between the oscillations in an adiabatic container in liquid helium II and those of a gas in a Helmholtz resonator is suggested and discussed.
CHARACTERISTIC TEMPERATURES OF CUBIC METALS
Authors: Budzinski E. E. , Schiff H.
Published: April 2011

An approximation is developed for the determination of the characteristic Debye temperatures of cubic crystals. This method yields results more accurate than those obtained by Bhatia and Tauber using Houston's three-term formula and slightly more accurate than those obtained with the more recent six-term formula of Betts, Bhatia, and Wyman, and also provides a means of estimating the accuracy of these formulae.
A CONSIDERATION OF RADIO STAR SCINTILLATIONS AS CAUSED BY INTERSTELLAR PARTICLES ENTERING THE IONOSPHERE: PART I. DAILY AND SEASONAL VARIATIONS OF THE SCINTILLATION OF A RADIO STAR
Authors: Harrower G. A.
Published: April 2011

An analysis is made of measurements of the scintillations of the radio source in Cassiopeia recorded at Ottawa during 1954 at a frequency of 50 megacycles per second. After removal of the effect of the altitude of the source, the data show certain daily maxima occurring at solar times dependent on the date of the year. These maxima are found to comprise five separate groupings, two being present roughly from September 13 to March 30, and the other three for the remainder of the year. The obvious lack of circular symmetry suggests a cause external to the solar system, such as the infall of interstellar particles. The apparent directions of arrival of these particles are derived from the scintillation measurements.
A CONSIDERATION OF RADIO STAR SCINTILLATIONS AS CAUSED BY INTERSTELLAR PARTICLES ENTERING THE IONOSPHERE: PART II. THE ACCRETION OF INTERSTELLAR PARTICLES AS A CAUSE OF RADIO STAR SCINTILLATIONS
Authors: Harrower G. A.
Published: April 2011

A previously reported analysis of measurements of radio star scintillations, which showed daily variations dependent on time of year, is here interpreted to be the result of the accretion of interstellar particles by the Sun's gravitational field. After a brief general discussion of the accretion process, the measurements are examined in an attempt to provide an explanation on that basis. Five distinct features exhibited by the scintillation data are interpreted as resulting from particles arriving at the Earth as follows: directly from interstellar space, from a collision region behind the Sun (both directly and after having crossed the Earth's orbit), and from the collision region by a process of accretion in the gravitational field of the Earth. The velocities of certain of these particles are derived by simple applications of vector addition employing the known velocity of the Earth. The collision region is calculated to be located a radial distance of 200 million miles from the Sun.
THE FRACTURE ZONES OF OROGENESIS
Authors: Robinson R. O. A.
Published: April 2011

A brief discussion of existing theories of orogenesis leads on to a consideration of the mode of propagation of a series of primary arcs. One such series constitutes a system, and it is suggested that the great orogenetic belts are best understood in terms of subdivisions into such systems. Explanations are given of the secondary structures and of the observed features at junctions between pairs of arcs and between pairs of systems. Among the latter the most notable are extensive, shallow transcurrent faults. In the past these have been analyzed in terms of states of stress persisting over long periods of time. It is suggested that this is incorrect and that they result from splay-faulting during the formation of the junction. It is shown that their character and strike are entirely determined by the relative age of the arcs forming the junction. Since echelon structure represents simply a series of such small transcurrent faults, it follows that it reveals completely the order of growth (through time) of a given primary arc. The resulting conclusions are in good agreement with the known geology, and it is felt that the methods derived will help to clarify considerably the orogenetic development of systems only imperfectly mapped to date. Reversed arcs are thought to occur only at junctions between two systems as distinct from junctions between two primary arcs of the same system.
SPHERICAL-HARMONICS METHOD FOR NEUTRON-TRANSPORT PROBLEMS IN CYLINDRICAL GEOMETRY
Authors: Davison B.
Published: April 2011

The paper deals with the application of the spherical-harmonics method to systems with complete cylindrical symmetry, that is, to systems invariant under rotation around and translation parallel to an axis. Closed-form expressions are given in an arbitrary order of approximation both for the spherical-harmonics moments in terms of the constants of integration and, conversely, for the constants of integration in terms of the spherical-harmonics moments. This removes the need for numerical inversion of matrices and simplifies the treatment of multilayer problems.
AN INVESTIGATION OF SOME BARIUM TITANATE COMPOSITIONS FOR TRANSDUCER APPLICATIONS
Authors: Schofield D. , Brown R. F.
Published: April 2011

The most important factor limiting the use of barium titanate in high power electroacoustic transducer applications is the large dielectric loss in high exciting fields. It has been shown that the addition of cobalt to 5% calcium, 95% barium titanate compositions produces a large reduction in the loss in high fields without significantly affecting the piezoelectric constants of polarized ceramic.
SPECTRES DE VIBRATION-ROTATION DE MOLECULES SIMPLES DIATOMIQUES OU POLYATOMIQUES AVEC LONG PARCOURS D'ABSORPTION: XII. LE SPECTRE DE C12O162 ENTRE 3500 ET 8000 CM−1 ET LES CONSTANTES MOLECULAIRES DE CETTE MOLECULE
Authors: Courtoy Charles-P.
Published: April 2011

Numerous absorption bands of the molecule C12O162 have been obtained in the near infrared under high resolution with the help of a multiple path absorption cell. Of these bands, 27 have been analyzed, among them three Δ—Δ transitions.The usual formula for the vibrational levels has been extended to include cubic terms and the values of the vibrational constants are given. Similarly the rotational constants Bν have been expressed by a formula including quadratic terms and the constants in this formula are given. The values of B0 and Be obtained here are respectively 0.39021 ±.00004 and 0.39162 cm−1.The l-type doubling constant qν of the Π states (apart from effects of Fermi resonance) can be represented by[Formula: see text].The perturbation term of the Fermi resonance is given by the expression[Formula: see text],where the quantum number l does not enter the first factor. The introduction of this expression allows one to represent all the vibrational levels as well as the rotational constants of each level and the constant q of the Π states with excellent precision.The value of D0 is found to be 13.5 × 10−8 cm−1. The effect of the Fermi resonance and of the perturbation between levels (ν1, ν2, l, ν3) and (ν1, ν2, l ± 2, ν3) on the constants D is discussed. The experimental values for these constants agree in a very satisfactory way with those calculated by Amat, Goldsmith, and Nielsen as do the constants μ of l-type doubling of the Π states.Finally the effect of Coriolis perturbation between the levels 3200 and (0511)c is demonstrated.
IRON 60
Authors: Roy Jean-Claude , Kohman Truman P.
Published: April 2011

The long-lived radionuclide Fe60 has been observed through extraction of its disintegration product, 10-minute Co60m, from the iron fraction isolated from a copper target bombarded with ~400-Mev. protons. Direct observation was prevented by the Fe59 present. Yield considerations indicate the Fe60 half-life to be ~3 × 105 years, uncertain by a factor of 3.
NUCLEAR RADIATION WIDTHS
Authors: Cameron A. G. W.
Published: April 2011

The total radiation widths of nuclear energy levels have been computed using the new level spacing formula of T. D. Newton. The only adjustable constant in this calculation is a normalizing factor, which was determined by comparison with observed radiation widths. The logarithmic average deviation of the observed radiation widths from the calculated values is then equal to a factor 1.37. Radiation widths computed for a series of nuclei close to the valley of beta stability at excitation energies corresponding to the energy release in neutron capture are presented. It is found that in heavy nuclei with large level spacings the radiation widths of electric dipole transitions to the ground state can exceed that computed from the above considerations. This accounts for the unusual nature of the radiative transitions in lead.
VARIATIONS IN THE INTRINSIC STRENGTH OF THE 1956 QUADRANTID METEOR SHOWER
Authors: Hines C. O. , Vogan E. L.
Published: April 2011

The occurrence rate of meteoric signals, detected on a V.H.F. forward-scatter path, is analyzed for the time of the 1956 Quadrantid shower. The detection rate of the shower meteors is converted to an incidence rate, by use of the appropriate forward-scatter theory. The variation in the intrinsic strength of the shower is thereby determined, on an hour-to-hour basis, and it is compared with variations which have been obtained in other years by other methods. The comparison reveals a distinct secular shifting of the orbit of the Quadrantid meteor stream. It also illustrates the marked advantage of the new technique in assessing variations in the strengths of short-lived showers.
THE EFFECT OF PRESSURE ON THE ELECTRICAL RESISTANCE OF RUBIDIUM
Authors: Dugdale J. S. , Hulbert J. A.
Published: April 2011

By using helium in both the solid and the fluid state as a pressure-transmitting medium, it has been possible to measure the resistance of rubidium over the temperature range from 2° K. to room temperature at pressures up to 2500 atmospheres. In particular the effect of pressure on the transition at ~200° K., on the low temperature ideal resistivity, and on the residual resistivity was examined.
VELOCITY-JUMP AMPLIFICATION AT 10,000 MC./S.
Authors: Dore B. V.
Published: April 2011

A vacuum tube using the velocity-jump principle was built to amplify microwave frequencies in the vicinity of 10,000 Mc./s. The design of the tube was based on a similar structure that had been built to operate at a lower frequency. A general theory previously developed for space-charge wave amplifiers was applied to the operation of the tube, in conjunction with approximations made to the theory of coupling to electron beams by means of helices. The experimentally measured gain was in moderate agreement with that predicted by this theoretical development. Conclusions are drawn regarding the operation of coupling helices, and the effect of small gaps in the amplifying section of the tube.
THE WAVELENGTH DISPLACEMENTS OF SOME INFRARED LINES BETWEEN LIMB AND CENTER OF THE SUN
Authors: Herzberg Luise
Published: April 2011

The wavelength displacements between the solar limb and the center of the disk, (λL–λc), have been measured for six infrared solar lines, belonging to two multiplets of Sil. The displacements of the lines of one of the multiplets are the same, within the accuracy of the measurements; the displacements of the lines of the other multiplet, although varying somewhat amongst themselves, are systematically larger. This grouping of the results according to multiplet structure suggests that the wavelength displacement of solar lines across the disk is term-dependent. It is noted that the variation of the values (λL–λC) is, in its essential features, similar to the term-dependent variation of the differences [Formula: see text] between the published solar and laboratory wavelengths of silicon. Solar and laboratory data, taken together, appear to provide observational evidence that the observed wavelength variations across the solar disk are, at least in part, due to collision or field effects.
A NEW TECHNIQUE FOR THE STUDY OF SCATTER PROPAGATION IN THE TROPOSPHERE
Authors: Chapman J. H. , Heikkila W. J. , Hogarth J. E.
Published: April 2011

The power spectrum of the fluctuations in received signal strength on a near-optical U.H.F. circuit has been measured. The sidebands associated with these fluctuations can overlap the information-carrying sidebands of a communication system. When this happens, these sidebands must be taken into account in determining the signal-to-noise ratio of the system. In other words, the fluctuations then have the characteristics of noise, and therefore they are called propagation noise in the present paper. Experiments at a carrier frequency of 500 Mc. have shown that the propagation noise power density usually varies with sideband frequency ƒ (measured from the carrier) as 1/ƒ2, for f in the range 0.1 to 10 c.p.s. Departures from this law have been observed in the regions near 0.1 c.p.s. and 10 c.p.s. The measurement of the power spectrum directly offers several advantages over the conventional signal strength recording method, and these are discussed herein.
HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: X. ROTATIONAL SPECTRUM OF BUTATRIENE (H2C=C=C=CH2)
Authors: Stoicheff B. P.
Published: April 2011

The rotational Raman spectrum of butatriene (H2C=C=C=CH2) at a pressure of 2 cm. Hg was photographed with a 21 ft. grating spectrograph. An analysis of this spectrum (based on the symmetric top approximation) yields the rotational constant [Formula: see text](B0 + C0) = 0.13141 ± 0.0001 cm−1. If the two outer C=C bonds in butatriene are assumed to have the same length as the C=C bonds in allene,namely 1.309 Å, it is found that the central C=C bond has a length of 1.284 ± 0.006 Å, a value which is shorter than that of the C=C bonds in ethylene and in allene.
LOW TEMPERATURE RESISTIVITY OF TRANSITION ELEMENTS: VANADIUM, NIOBIUM, AND HAFNIUM
Authors: White G. K. , Woods S. B.
Published: April 2011

Measurements of the thermal conductivity from 2° to 90 ° K. and electrical conductivity from 2° to 300 ° K. are reported for vanadium, niobium, and hafnium. Although the vanadium and hafnium are not as pure as we might wish, measurements on these metals and on niobium allow a tabulation of the "ideal" electrical resistivity clue to thermal scattering for these elements from 300 ° K. down to about 20 ° K. Ice-point values of the "ideal" electrical resistivity are 18.3 μΩ-cm. for vanadium, 13.5 μΩ-cm. for niobium, and 29.4 μΩ-cm. for hafnium. Values for the "ideal" thermal resistivity of vanadium and niobium are deduced from the experimental results although for vanadium and more particularly for hafnium, higher purity specimens are required before a very reliable study of "ideal" thermal resistivity can be made. For the highly ductile pure niobium, the superconducting transition temperature, as determined from electrical resistance, appears to be close to 9.2 ° K.
ABSORPTION OF SUNLIGHT BY ATMOSPHERIC SODIUM
Authors: Scrimger J. A. , Hunten D. M.
Published: April 2011

A photometer has been built which is sensitive to light only in a very narrow spectral region near the sodium D-lines. The light is scattered by sodium vapor at low density and the scattered light recorded by a photoelectric spectrometer. The latter resolves the two lines and allows the effect of stray light to be eliminated. With sunlight as the source, the radiation detected is at the bottom of the Fraunhofer lines and the residual intensity there may be measured. It is found that this intensity decreases slightly (relative to the continuum) as the sun approaches the horizon. This effect is attributed to atmospheric sodium; the amount found by this method agrees well with that deduced from twilight measurements. The thickness of the sodium layer in atoms/cm.2 varies between 3 and 9 × 109 in winter and is about 1 × 109 in April. The measurements also give the residual intensities of the Fraunhofer lines in the incident sunlight, averaged over the whole of the sun's disk. These are (5.90 ± 0.46)% for D1 and (5.06 ± 0.24)% for D2.
THE DECAY OF THE POPULATIONS OF METASTABLE ATOMS AND IONS FROM THE SAME D-C. DISCHARGE IN NEON
Authors: Blevis B. C. , Anderson J. M. , McKay R. W.
Published: April 2011

Measurements of electron density and of the population of the 3P2 metastable state have been made following cessation of a d-c. discharge in neon gas. Determinations of these populations were made under identical conditions at accurately determined times after termination of the discharge and decay curves were plotted for a pressure range from 0.5 to 12.0 mm. Hg. At low pressures, where diffusion is the principal factor in the decay, both curves are exponential and show the same mean life, within the limits of error. Values of the diffusion constants obtained from these curves are consistent with the results of previous workers in both fields. At higher pressures the metastable decay remains exponential while the reciprocal of the electron population changes linearly with time. In general, the two decays are unrelated. Only at the highest pressure studied, and in this case for only the first half millisecond, was a measurable effect of positive ion recombination found in the metastable population curve.
QUANTUM MECHANICS WITH AN INDEFINITE METRIC
Authors: Gupta Suraj N.
Published: April 2011

The formalism of quantum mechanics in a vector space with an indefinite metric is developed in a simplified way, and the properties of the indefinite vector space are discussed in detail with particular attention to vectors of negative and vanishing norms. It is shown how the present formalism simplifies the use of the indefinite metric in physical applications.
MEASUREMENT OF THE COMPLEX DIELECTRIC CONSTANT OF LIQUIDS AT CENTIMETER AND MILLIMETER WAVELENGTHS
Authors: Mungall A. G. , Hart John
Published: April 2011

The measurement of the complex dielectric constant of lossy liquids in the millimeter and centimeter wave region by a free-space technique is described. The method involves the measurement of absorption per wavelength and of reflectance at normal incidence. Families of curves are given for the relations between these two quantities and the real and imaginary parts of the complex dielectric constant. Results for ethyl and methyl alcohol at 9 and 13 mm. wavelength are compared with those obtained by waveguide techniques.
THE LOW LEVELS OF Si29
Authors: Bromley D. A. , Gove H. E. , Litherland A. E. , Almqvist E. , Paul E. B.
Published: April 2011

Information on the low levels in Si29 has been obtained by studying the gamma radiation associated with the Si29(p, p′γ)Si29 inelastic-scattering reaction in the proton-energy range from 2.5 to 3.0 Mev. and with the Al29(β−)Si29 negatron decay. Angular-distribution measurements have shown that the 2.03 Mev. level in Si29 has spin 5/2, and are consistent with a 3/2 assignment to the 1.28 Mev. level. The E2/M1E2 branching ratio for the de-excitation of the 2.03 Mev. state has been measured to be approximately 100. Log ft values of < 5.2, > 6.5, and 5.2 have been determined for the branches of the Al29 decay to the 2.43, 2.03, and 1.28 Mev. states in Si29.
SCANDIUM ISOTOPE OF MASS 42
Authors: Cloutier J. A. R. , Henrikson A.
Published: April 2011

A member of the odd–odd Z = N family, Sc42, has been produced by proton bombardment of a calcium target greatly enriched in Ca42. The positron emission, which alone is observed, has a measured half-life of 0.68 second, end point 4.8. Mev., and threshold 6.8 Mev. The superallowed transition is between ground states (J, T) tentatively described as Sc42 (0+, 1) and Ca42 (0+, 1).
TIME REVERSAL EFFECTS IN MUON DECAY
Authors: Sharp Robert T. , Bach Glen
Published: April 2011

Expressions are given for the distribution of electrons emitted in the decay of aligned muons as a function of their energy, direction, and spin. The two-component neutrino theory of Yang and Lee is used, and two cases are considered: (i) neutrino and antineutrino emitted; (ii) two neutrinos emitted. Various correlation terms arise as a result of the inclusion of electron spin. Among these is a time reversal dependent term whose presence would be evinced by asymmetry in a transverse polarization of electrons emitted at right angles to the muon spin.
ULTRAVIOLET SPECTRA OF LiH AND LiD
Authors: Velasco R.
Published: April 2011

The absorption spectra of LiH and LiD have been observed in the near ultraviolet with high dispersion and absorbing path lengths up to 16 meters. A new band system has been found in each molecule involving the ground state and a 1Π excited state. Rotational and vibrational analyses of this system have been carried out and rotational and vibrational constants for the upper state have been determined. The observed breaking off of the rotational structure of the bands of this B1Π—X1Σ+ system has been interpreted as due to predissociation by rotation. With this assumption very accurate dissociation limits of the B1Π state have been obtained. From these dissociation limits the dissociation energies of the three known electronic states of LiH and LiD have been calculated. In particular the dissociation energies (D0) of the ground states of LiH and LiD have been found to be 2.4288 ± 0.0002 ev. and 2.4509 ± 0.0010 ev., respectively.
REACTOR NEUTRON CAPTURE CROSS SECTION OF 51-DAY Sr89
Authors: Roy L. P. , Roy J. C.
Published: April 2011

The neutron capture cross section of Sr89 has been measured by an activation method. Naturally occurring strontium was irradiated in different high flux positions in the NRX reactor at Chalk River and the amount of Sr90 formed by successive neutron capture in Sr88 was determined by separating and measuring its daughter Y90. Using values of 36.6 and 0.005 barns for the respective neutron capture cross sections of Co59 and Sr88, the capture cross section of Sr89 for reactor spectrum neutrons was found to be 0.49 ± 0.10 barn.
ISOTOPE SHIFT IN THE RESONANCE LINES OF Mg I
Authors: Kelly F. M.
Published: April 2011

Measurements of the isotope shift in λ2852 (3 1S0—3 1P1) and λ4571 (3 1S0—3 3P1) of Mg I are reported. The new measurements are compared with other results and with theoretical calculations.
THE SPECTRUM OF THE P2+ MOLECULE
Authors: Narasimham N. A.
Published: April 2011

Two band systems attributed to the P2+ molecule have been excited in a hollow cathode discharge tube. The first of these is a 2Π—2Π band system lying in the region 3400–3850 Å. The lower state of this system probably is the ground state of the P2+ molecule. The second system is a 2Σ—2Σ system lying in the region 3900–4400 Å. High resolution spectra of both the band systems have been analyzed and the rotational and vibrational constants determined.
A CONTINUOUSLY RECORDING AUTOMATIC AURORAL RADAR
Authors: McNamara A. G.
Published: April 2011

A simple, low-power 50 Mc./s. radar is described which has been designed for automatic recording of radio reflections from auroral ionization. The system features high sensitivity with good reliability. Photographic records are taken in the form of a continuous film strip displaying range and time. A complementary recording system employs circuitry which cancels interference and noise signals but produces an output signal proportional to the integrated echo intensity. The display in this latter case is in the form of a chart record from which data are immediately available.
ON THE THEORY OF PROPAGATION OF ELECTROMAGNETIC WAVES ALONG A CURVED SURFACE
Authors: Wait James R.
Published: April 2011

The problem of propagation of vertically polarized waves along a surface whose curvature and electrical properties have a discontinuity is considered. The mutual impedance Z between two short vertical antennas on either side of the boundary of separation is considered to be the fundamental quantity which is sought. By utilizing the principle of stationary phase and the concept of surface impedance, an approximate expression is derived for Z. It is shown that to a first order of magnitude, the effects of the conductivity contrast and curvature change are additive corrections to the mutual impedance between dipoles over a single homogeneous spherical surface.
THE VISCOSITY OF LIQUID HELIUM AT FREQUENCIES OF 11.8 AND 35.5 KC./SEC.
Authors: Eisele K. M. , Hallett A. C. Hollis
Published: April 2011

A solid cylinder set into torsional oscillation at its natural frequency has been used to measure the viscosity of liquid helium in the range 4.2 ° K. to 1.2 ° K. Values of the viscosity calculated from the logarithmic decrement of the decay of the oscillations at the natural frequency of 11.8 kc./sec. of the cylinder are in good agreement within the errors, which are of the order of 30%, with the most recent oscillating disk values. Values obtained at a frequency of 35.5 kc./sec. (a harmonic of the cylinder) might be of the order of 10% lower. The depth of penetration of the viscous waves in these experiments was less than 5 × 10−5 cm.
ABSORPTION SPECTRA OF THE HALOGEN MONOXIDES
Authors: Durie R. A. , Ramsay D. A.
Published: April 2011

Absorption spectra of ClO, BrO, and IO have been observed during the flash photolysis of Cl2–O2, Br2–O2, and I2–O2 mixtures. Rotational and vibrational analyses of the ClO and BrO spectra have been carried out and appropriate molecular constants derived. The transitions are of the type 2Πi(case a)—2Πi (case a). Extensive predissociation has been observed in all three spectra. Theoretical and experimental evidence is presented to show that the excited states dissociate to X(2P3/2) + O(1D). From the observed or extrapolated convergence limits of the absorption spectra the dissociation energies of the ground states are shown to be D0″(ClO) = 63.31 ± 0.03 kcal./mole, D0″ (BrO) = 55.2 ± 0.6 kcal./mole, D0″ (IO) = 42 ± 5 kcal./mole. Mechanisms for the production of the halogen monoxides are discussed and evidence is presented for the participation of excited [Formula: see text] halogen atoms.
A LARGE-AREA LIQUID SCINTILLATION COUNTER AND SOME MEASUREMENTS ON HIGH-ENERGY COSMIC-RAY PARTICLES
Authors: Millar C. H. , Hincks E. P. , Hanna G. C.
Published: April 2011

A liquid scintillation counter is described which consists of a [Formula: see text] in. by [Formula: see text] in. by 2 in. Plexiglas tank of terphenyl plus α-naphthylphenyloxazole (αNPO) in triethylbenzene. The tank is surrounded by MgO powder and viewed by a total of eight RCA Type 5819 photomultiplier tubes along two opposite edges. For normally incident fast μ-mesons a peaked pulse height distribution is observed, 20.5% in width at half-maximum for the central area of the counter, broadening to 25–30% at the perimeter, and estimated to be 25% over-all. When the Landau distribution in energy loss (width 18% at half-maximum) and the geometric spread are taken into account, a counter resolution function 8% in width at half-maximum is obtained for the central area of the counter, or 18% for the counter as a whole.The most probable pulse height for 0.30 Bev. μ-mesons is 1.6 ± 0.5% higher than for 2.2 Bev. μ-mesons, in close agreement with the Bethe–Bloch theory as extended by Symon and with a density correction calculated by the method of Sternheimer. Pulse heights from protons in the region 0.3 to 0.8 Bev. vary directly with the theoretically computed energy loss in the counter. Peak position and resolution are unchanged by a flux of 12 mr./hr. of thorium γ-rays.
MASS ASSIGNMENT OF THE 1.8 HOUR YTTERBIUM ACTIVITY
Authors: Betts R. H. , Dahlinger Olive F. , Munro Donna M.
Published: April 2011

The rate of growth of Lu177 into neutron-irradiated ytterbium has been measured by radioassay of lutetium fractions separated by ion-exchange techniques. Such measurements show the parent of Lu177 to be the 1.8 hour Yb; this latter nuclide is therefore Yb177. Confirmatory values of 3.71 ± 0.04 hours and 6.75 ± 0.05 days have been obtained for the half-lives of Lu176m and Lu177.
THE EFFECT OF HEAT TREATMENT ON LOW TEMPERATURE INTERNAL FRICTION MAXIMA
Authors: Hutchison T. S. , Hutton G. J.
Published: April 2011

Measurements of the attenuation of sound at a frequency of 5 megacycles have been made over the temperature range 100° to 200 ° K. on polycrystalline high purity aluminum subjected to various thermal and mechanical treatments. With samples annealed at 520 °C. a maximum in the attenuation versus temperature relation had been observed at 155 ° K. This maximum was greatly increased by small amounts of plastic deformation of the order of 1.0 to 1.5%.Aluminum initially annealed for extended periods at temperatures much closer to the melting point shows, however, either no increase in the attenuation maximum at 155 ° K. or, in extreme cases, no maximum in this region at all, after plastic deformation of the same order as before. It is believed that this indicates a dependence of the deformation-induced maximum on the distribution and possibly on the number of dislocations in the metal prior to deformation and on the arrangement of the dislocations after deformation.
PRESSURE-INDUCED INFRARED ABSORPTION OF HYDROGEN AND HYDROGEN – FOREIGN GAS MIXTURES IN THE RANGE 1500–5000 ATMOSPHERES
Authors: Hare W. F. J. , Welsh H. L.
Published: April 2011

The pressure-induced infrared absorption of hydrogen was studied in pure hydrogen and in hydrogen–helium, hydrogen–argon, and hydrogen–nitrogen mixtures at pressures up to 5000 atm. at room temperature. The integrated absorption coefficient can be expressed in the form α1ρaρp + α2ρaρp2 over the whole range of densities (ρa = density of H2, ρp = density of the perturbing gas, [Formula: see text] in the mixture experiments). The coefficient α2 is much smaller than predicted from the effect of finite molecular volumes; this is interpreted as a partial cancellation of the induced moments in ternary collisions. The splitting of the Q branch of the fundamental, which is due to the participation of the relative kinetic energies of the colliding molecules in the absorption process, increases linearly with the density because of ternary collisions; a more rapid increase observed at very high densities is not yet explained. The components of the overtone and double vibrational transition, like the QQ and S components of the fundamental, show no splitting or broadening with increasing density; these absorptions are believed to be due to quadrupole interactions while the QP and QR components of the fundamental are due to overlap interactions.
THE LUMINESCENCE RESPONSE OF PHOSPHORS TO LOW ENERGY ION BOMBARDMENT
Authors: Eve C. F. , Duckworth H. E.
Published: April 2011

The luminescence response of samples of ZnS:Ag and Zn2SiO4:Mn to bombardment with various ions was determined as a function of the ion energy. For ZnS:Ag, within the range of ion energies studied (E < 25 kev.), the luminescence response, L, is related to the ion energy, E, according to [Formula: see text]. E0 is a threshold energy which is not a very sensitive function of ion mass. For Zn2SiO4:Mn no threshold energy was observed except in the case of Li7+ ions, the lightest ions used with this phosphor. The experimental results for ZnS:Ag appear to be consistent with a theory in which it is assumed that the bombarding particles penetrate the phosphor as neutral atoms and produce luminescence by electronic excitation of the lattice atoms due to small impact parameter collisions.
HORIZONTAL MOVEMENTS OF AURORA
Authors: Kim J. S. , Currie B. W.
Published: April 2011

Measurements on the drifts of auroral forms at three stations to the south of the auroral zone in West-Central Canada failed to show evidence of a motion due to the earth's rotation relative to fixed excitation patterns in space. The distribution and the magnitude of the speed of auroral structures parallel and normal to the geomagnetic meridians are substantially the same as for non-luminous ionic irregularities observed by radio methods. The speed of an auroral arc or band parallel to the geomagnetic meridian is apparently constant. Speeds increase with geomagnetic activity, particularly in an east-west direction. There is no definite indication of a reversal of the east-west motions close to local midnight. Speeds and directions show no characteristic variations with the time of night.
MASS SPECTROMETRIC ANALYSIS OF SOME HYDROGEN OXIDES. I
Authors: Kerwin Larkin , Cottin Maurice
Published: April 2011

Typical mass spectrograms for H2O, D2O, H2O2, and D2O2 are presented. Both positive and negative ions were observed. The variations of the abundances of the spectrogram components with pressure are given. Some features of the experimental data are discussed.
ON VOLTERRA'S DISLOCATIONS IN A SEMI-INFINITE ELASTIC MEDIUM
Authors: Steketee J. A.
Published: April 2011

In this paper a Green's function method is developed to deal with the problem of a Volterra dislocation in a semi-infinite elastic medium in such a way that the boundary surface of the medium remains free from stresses. (A Volterra dislocation is here defined as a surface across which the displacement components show a discontinuity of the type Δu = U + Ω ×r, where U and Ω are constant vectors.) It is found that the general problem requires the construction of six sets of Green's functions. The method for the construction is outlined and applied to one of the six sets, which is of the type of two double forces with moments in a plane parallel with the boundary. The displacement field thus generated is computed. Several of the results obtained are believed to be of geophysical interest, but a more detailed discussion of these applications is postponed to a further communication which is being prepared.
A SEARCH FOR α-PARTICLES FROM THE DECAY OF Bi209
Authors: Hincks E. P. , Millar C. H.
Published: April 2011

A search for α-particles from Bi209 has been carried out in Ilford C-2 bismuth-loaded nuclear emulsions maintained at 5 °C. for 3 years before development. Contrary to the findings of Faraggi and Berthelot (1951), Riezler and Porschen (1952), and Porschen and Riezler (1956), no evidence was obtained of α-particles in the 3 Mev. region which could be unambiguously attributed to bismuth, the experimental lower limit for the half-life thus determined being [Formula: see text] years. A detailed study of the energy available for the α-disintegration of Bi209 by the method of reaction cycles gives a value of 2.93 ± 0.11 Mev. For this disintegration energy the half-life of Bi209 predicted on the basis of α-decay theory and systematics is between 5 × 1019 and 5 × 1022 years.
THE TOWNSEND DISCHARGE IN A COAXIAL DIODE WITH AXIAL MAGNETIC FIELD
Authors: Redhead P. A.
Published: April 2011

An approximate theory is developed of the breakdown characteristics of a coaxial diode in an axial magnetic field, taking into account the effects of elastic collisions. It is assumed that the electron moves in a constant electric field between collisions and thus the theory is valid only in the appropriate range of magnetic field and voltage. Estimates of transit time and of space-charge effects are also made. Measurements in the pressure range 10−3 to 10−9 mm. Hg are in general agreement with the theory.
A SURVEY OF THE MATHEMATICS AVAILABLE FOR DESCRIBING FRACTURE
Authors: Scheidegger A. E.
Published: April 2011

An attempt is made to extend the mathematical finite strain theory of general rheological bodies to the inclusion of discontinuous displacements, i.e. to the description of fractures and related phenomena. A general analytical representation of discontinuities is given. A particularly simple type of discontinuity has been singled out for special investigation, i.e. "dislocations". The notion of "dislocation" is investigated from the standpoint of finite strain theory and several theorems are proved. Finally, the requirements for the establishment of a dynamic theory of fractures are outlined. It is shown that the mathematical theory cannot be carried further without additional physical investigations. The direction in which these have to be sought is indicated.
ON THE SPIN–ORBIT INTERACTION IN DIATOMIC MOLECULES. II
Authors: Kovács I.
Published: April 2011

This paper deals with perturbations between states of even multiplicity in a three-electron system. With the aid of the matrix elements which have been obtained, a comparison of the perturbations in the various components of a given state and in some cases a comparison of perturbations in two different states is possible. Also for certain cases it has been possible to establish relationships between the matrix elements which give the magnitude of the perturbations and experimentally measurable molecular constants of the perturbed states.
BAND STRUCTURE OF RHOMBOHEDRAL GRAPHITE
Authors: Haering R. R.
Published: April 2011

The band structure of rhombohedral graphite has been investigated using the nearest-neighbor tight-binding approximation. The resulting behavior of the π-bands near the Fermi surface is more complex than in the case of the Bernal stacking. The two π-bands still touch, but the touching points no longer lie on the edges of a hexagonal prism in k-space. Instead, they lie on cylinders whose axes are the edges of the hexagonal prism. The radii of these cylinders are proportional to γ1, the nearest "out-of-plane" exchange integral. The de Haas – Van Alphen effect in the rhombohedral structure may be expected to yield useful information about the magnitude of γ1.
MECHANICAL STRENGTH OF ICE FROZEN FROM AN IMPURE MELT
Authors: Pounder E. R.
Published: April 2011

Ice frozen from a melt containing a small amount of a light alcohol, ketone, or ether is much weaker than normal ice, for a limited freezing exposure. The weakening effect is enhanced if the melt also contains traces of one or more of a variety of long-chain, organic substances, one of the most effective being sodium carboxymethyl cellulose. Inorganic salts, on the other hand, appear to be largely ineffective and may even cancel out the weakening action of the organic solvent. It is suggested that the organic additives are concentrated in the surface of the melt and remain as liquid layers between the ice crystals, thereby causing a large reduction in the shear strength of the ice sheet. Adsorption at the surface is discussed as a mechanism for concentrating organic substances in the surface layer and rejecting inorganic salts into the interior of the solution.
NOTE ON THE FORCED AND DAMPED OSCILLATOR IN QUANTUM MECHANICS
Authors: Kerner Edward H.
Published: April 2011

The wave equations for the forced, damped, and forced and damped oscillators are solved in closed form for an arbitrary forcing function; the solutions produced being in one-to-one correspondence with the stationary states of the unforced, undamped Hamiltonian H0. The quantal motion is closely connected with the classical: for the forced oscillator the probability density is that of H0 but moves as a whole with the classical motion; for the forced and damped oscillator this motion is accompanied by a contraction progressing eventually into a delta function at the classical position. Transition probabilities between states of H0 are computed in the case of forced motion and depend solely on the classically acquired energy of the oscillator at any time. The transition probability vanishes strictly only when this energy has a value falling at the roots of a Laguerre polynomial associated with the transition. The classical dipole radiation emitted by a disturbed oscillator is, when the damping force is identified with the force of radiation damping, that of the classical oscillator: a shifted and broadened line.
SOME PHOTONEUTRON THRESHOLDS
Authors: Chidley B. G. , Katz L. , Kowalski S.
Published: April 2011

The photoneutron thresholds for a number of elements which have 100% abundance (or nearly so) in one stable isotope have been measured. The following values in Mev. were found:[Formula: see text]
ANGULAR ENERGY FLUX OF SECONDARY GAMMA-RAYS IN MATTER: SMALL-ANGLE SCATTERING FROM A POINT ISOTROPIC SOURCE
Authors: Dixon W. R.
Published: April 2011

The distribution in energy and angle of secondary gamma-rays in matter is studied, with particular reference to small angles and to energies near the incident energy. The "angular energy flux" arising from a point isotropic source in matter is calculated, using small-angle approximations, and compared with experimental data obtained for a Cs137 source in concrete. It is concluded that for small angles and for energies near the incident energy, only a few orders of scattering contribute to the angular energy flux out to considerable thicknesses, whereas for large angles and low energies many orders of scattering contribute even for small thicknesses.
THE TIME-DEPENDENT DIFFUSION THEORY FOR CONDENSATION ON SPHERICAL AND PLANE SURFACES
Authors: Kirkaldy J. S.
Published: April 2011

The diffusion field and the temperature distribution are calculated for the surroundings of a pure solid or liquid phase at constant temperature growing into an infinitely extended binary fluid phase of different specific volume. The solutions for spherical condensates are applicable to the condensation from air of water vapor on ice crystals or water drops. It is demonstrated that the generally accepted quasi-stationary diffusion theory for spherical drops leads fortuitously to the correct growth law.
ABSORPTION IN A DIELECTRIC SLAB
Authors: Bachynski M. P.
Published: April 2011

The amount of incident energy transmitted, reflected, and absorbed by a parallel slab of lossy, high-dielectric-constant material is derived. The results are general for any angle of incidence, and calculations are presented for some lossy, high-dielectric-constant materials of one-half wavelength electrical thickness. At angles of incidence greater than 60°, the reflected energy is found to be the smaller the lossier the material. The absorbed energy is a maximum at certain angles of incidence which depend upon the polarization and dielectric constant.
SPHERICAL-HARMONICS METHOD FOR NEUTRON TRANSPORT THEORY PROBLEMS WITH INCOMPLETE SYMMETRY
Authors: Davison B.
Published: April 2011

The paper deals with the application of the spherical-harmonics method to neutron-transport problems in which the geometrical arrangement possesses spherical or cylindrical symmetry, but the distribution of sources and/or the conditions at infinity lack such symmetry. Certain classes of cases of this nature are considered, and for these, in an arbitrary-order approximation, the solution is given, in closed form, in terms of a finite number of Bessel functions.
THE ELECTRICAL BREAKDOWN OF SMALL GAPS IN VACUUM
Authors: Denholm A. S.
Published: April 2011

An investigation of the electrical breakdown in vacuum of small gaps subject to contamination by diffusion pump oil showed that the most consistent results were obtained when electrodes were conditioned by a hydrogen discharge. Even with this method of conditioning a few preliminary sparks were usually required before the breakdown voltage reached a plateau level, so that the vacuum discharge itself could affect the final values obtained. The circuit parameters which controlled the discharge current were found to influence the magnitude and consistency of the breakdown voltage appreciably.Direct, alternating, and impulse voltage tests showed that the time for which voltage was applied to the vacuum gap influenced the breakdown voltage, and curves are presented which give the insulation strength of the gap. Two possible explanations of the time dependence of the breakdown voltage are given.