bluuebunny/crossref_metadata_2025 huggingface dataset:
THE MOMENTUM AND VORTICITY TRANSFER THEORIES OF TURBULENT HEAT TRANSFER
Authors: Marris A. W.
Published: April 2011

The case of heat transfer by a cylindrical turbulent region is examined further theoretically from the standpoint of the vorticity transfer analogy. The radial distribution of the eddy diffusivity for vorticity is considered and, on the logarithmic velocity distribution law for fully developed turbulence, this quantity is found to be negative throughout an interval at the outer boundary of the turbulent region. When this region is excluded from the relevant integrals, results are obtained for the Nusselt modulus and radial temperature distribution for the particular case of Prandtl number equal to the ratio of the eddy diffusivities for vorticity and heat, and are compared with the corresponding results on the momentum transfer analogy theory.
ON A TWO-FLUID MODEL OF MATTER
Authors: Kaempffer F. A.
Published: April 2011

The theory of Pauli and Weisskopf is reformulated in hydrodynamical terms by introduction of a suitable density ρ and a suitable velocity potential [Formula: see text]. The Hamiltonian of the system is expressed in terms of ρ, [Formula: see text], and their canonical momenta. In accordance with a general program proposed by the author the transition to quantum theory is carried out along the lines of quantum hydrodynamics. The eigenvalues of the Hamiltonian corresponding to excitations of the motion with no net mass flow are obtained. Since these excitations do not give rise to an electromagnetic field, they are tentatively identified with neutrinolike particles. The picture emerging from these considerations is that of two interpenetrating fluids of positive and negative charge, in which different types of elementary particles appear as different types of excitations of the motion.
THE (γ, n) AND (γ, p) CROSS SECTIONS OF ARGON40
Authors: McPherson D. , Pederson E. , Katz L.
Published: April 2011

The (γ, n) and (γ, p) cross sections in A40 have been measured as a function of photon energy from threshold to 24 Mev. The (γ, n) cross section was found to have a peak value of 38 mbarns at 20 Mev. and an integrated cross section of 0.35 Mev-barn. These values for the (γ, p) cross section were found to be 120 mbarns at > 25 Mev. and 0.54 Mev-barn respectively. In spite of the higher (γ, p) threshold, it was found that the two cross sections were equal at 19.5 Mev. and above this energy the (γ, p) cross section became larger. This interesting result is discussed.
HIGH RESOLUTION RAMAN SPECTROSCOPY OF GASES: III. RAMAN SPECTRUM OF NITROGEN
Authors: Stoicheff B. P.
Published: April 2011

The pure rotational spectrum and the Q branch of the 1–0 band of N2 were photographed in the second order of a 21 ft. grating. An analysis of the rotational spectrum yields the rotational constants[Formula: see text]The value of B0 together with the Bν values obtained from the electronic bands of N2 gives[Formula: see text]Revised values of the vibrational constants have also been calculated using the results of the present work and the published data on the electronic spectra.
THE AMERICAN WIND TURBINE
Authors: Nilberg R. H.
Published: April 2011

The windmill theory published by Prof. A. Betz of Göttingen does not take into account the rotational motion of the air stream behind the mill, which is quite large behind the low-speed multiblade "American wind turbine". This paper presents a theory of the low-speed wind turbine showing that the shape of the airfoil blade is predetermined by the theoretical deflection of the air stream and should not be chosen arbitrarily. An increase of starting torque and efficiency of about twenty per cent may be expected.
SOME EXPERIMENTS AND THEORETICAL CONSIDERATIONS ON THE ELECTRIC H.F.S. METHOD OF NUCLEAR ALIGNMENT
Authors: Daniels J. M.
Published: April 2011

An account is given of two unsuccessful experiments to detect a nuclear electric quadrupole splitting in a solid by essentially thermal methods. In one experiment p-diiodobenzene was mixed with potassium chromium alum and cooled to 0.01°K. by adiabatic demagnetization, in an attempt to find the nuclear specific heat of the iodine. In another experiment, a single crystal of cobalt p-toluenesulphonate containing some I131 as p-iodobenzenesulphonate was cooled by adiabatic demagnetization, in an attempt to produce an alignment of the I131 nuclei and hence an anisotropic distribution of the emitted γ-rays.This is followed by a theory of the relaxation time for the transfer of heat from an assembly of nuclei with a quadrupole splitting to an assembly of paramagnetic ions in the same crystal. The behavior of the relaxation time is discussed with regard to variations of external magnetic field, and replacement of the nuclei or the paramagnetic ions with inert entities. A numerical estimate is made of the relaxation time of cobalt/zinc p-bromobenzenesulphonate for cobalt concentrations of 100% and 1%. The result of the two experiments is discussed in relation to the theory. An extension of the Casimir and du Pré relations to cover this case is given.
THE PROPAGATION OF AN ELECTROMAGNETIC WAVE ALONG AN INFINITE CORRUGATED SURFACE
Authors: Hurd R. A.
Published: April 2011

Propagation of an electromagnetic wave along an infinite corrugated surface whose slot walls are vanishingly thin is investigated using a method based on the calculus of residues. The method yields expressions for the amplitudes and phase velocities which are highly accurate near cutoff when the number of slots per wavelength is greater than about five.
SOME MASS SPECTROMETRIC DATA ON PHOSPHORUS
Authors: Kerwin Larkin
Published: April 2011

Investigation of red phosphorus with a mass spectrometer shows the element to be monoisotopic to 1 part in 50,000. The relative abundances of the molecules resulting from electron bombardment of natural phosphorus are given, and the existence of the molecule P8 in nature is reported.
CALCULATED DIFFRACTION PATTERNS OF DIELECTRIC RODS AT CENTIMETRIC WAVELENGTHS
Authors: Froese Charlotte , Wait James R.
Published: April 2011

Diffraction patterns are calculated for a cylindrical electromagnetic wave incident normally on a dielectric cylinder of infinite length whose diameter is comparable to the wavelength. Reasonably good agreement is obtained when the results are compared with published experimental results.
MASS SPECTROMETRIC STUDY OF NATURAL AND NEUTRON-IRRADIATED CHLORINE
Authors: Boyd A. W. , Brown F. , Lounsbury M.
Published: April 2011

Using a Nier-type mass spectrometer, the isotopic composition of chlorine gas obtained from natural potassium chloride has been measured to be 75.529 ± 0.016 atom per cent Cl35 and 24.471 ± 0.016 atom per cent Cl37, corresponding to a Cl35/Cl37 atom ratio of 3.0865 ± 0.0027. By comparison of this result with that for chlorine gas from potassium chloride irradiated for 14 months in a high flux position of the NRX reactor, the neutron capture cross-section of Cl36 has been determined to be 90 ± 25 barns. This value has been calculated on the assumption that only (n, γ) reactions were significant in changing the isotopic composition of the chlorine.
THE HALF-LIFE OF Cl36
Authors: Bartholomew Rosalie M. , Boyd A. W. , Brown F. , Hawkings R. C. , Lounsbury M. , Merritt W. F.
Published: April 2011

Cl36 was prepared by neutron irradiation of C.P. grade potassium chloride for 14 months in the NRX reactor. The disintegration rate of a purified sample of the irradiated material was determined by absolute beta counting with a 4π methane flow-type proportional counter. The number of Cl36 atoms in the sample was determined by gravimetric and mass spectrometric analysis. A value of (3.08 ± 0.03) × 105 years was obtained for the half-life of Cl36, assuming that the simple decay scheme is correct.
A NOTE CONCERNING THE CONDUCTIVITY OF LIQUID DIELECTRICS
Authors: Hart John , Simmons D. A.
Published: April 2011

Experiments are described which show that it is not permissible to ignore electrode effects in the calculation of the mobilities of ions in liquid dielectrics. Preliminary results indicate that the fall in direct current with time is due partly to electrode polarization, and partly to the removal of ions from the liquid. It has been found that for apparent field strengths lower than 1 kv./cm., the current in the dielectric is proportional to the applied potential, and there appears to be a back-e.m.f. of about one volt. Precautionary measures are suggested for future experiments.
THERMAL AND ELECTRICAL CONDUCTIVITIES OF SOLIDS AT LOW TEMPERATURES
Authors: White Guy K. , Woods S. B.
Published: April 2011

An apparatus for measuring the thermal and electrical conductivities of solids at temperatures between 2° and 300°K. is described. Results are presented of measurements of some dilute copper alloys, beryllium, bismuth, and germanium. Where possible the lattice thermal conductivity has been deduced, directly or indirectly from the measurements, and its magnitude and variation with temperature are discussed with relation to theory.
THE ELECTRICAL RESISTANCE OF DILUTE COPPER ALLOYS AT VERY LOW TEMPERATURES
Authors: White Guy K.
Published: April 2011

An adiabatic demagnetization cryostat for the measurement of electrical resistance of metals is described. Some preliminary results on copper containing small amounts of iron and tin are reported. These indicate that the rise in electrical resistance below the minimum is essentially complete in these specimens by ~ 2° K.
THE HALF-LIFE OF Sr90
Authors: Wiles D. M. , Tomlinson R. H.
Published: April 2011

The value of 27.7 ± 0.4 years has been obtained for the half-life of Sr90 from the absolute disintegration rate of a known number of atoms. The disintegration rate was measured with a 4π proportional counter and the number of atoms was determined with a mass spectrometer using isotope dilution.
THE VELOCITY OF PROPAGATION OF ELECTROMAGNETIC WAVES
Authors: Henderson J. T. , Mungall A. G.
Published: April 2011

Measurements of the velocity of propagation of electromagnetic waves have been carried out at a frequency of 400 Mc./sec., which is close to that employed for geodetic surveying in Canada. The results were consistent, giving a value for c of 299,780 km./sec. This value is probably low because the effect of discontinuities at the cavity junctions cannot be computed with certainty.
SCATTERING OF ELECTROMAGNETIC WAVES FROM A "LOSSY" STRIP ON A CONDUCTING PLANE
Authors: Wait James R.
Published: April 2011

One method for solving boundary value problems involving imperfectly conducting media is to assume, for a first approximation, that the surface currents are the same as if the media were perfectly conducting. Using this type of approximation, the problem of a line source of current situated over a plane surface, with a simple type of mixed boundary condition, is solved. For purposes of comparison the situation of an imperfectly conducting or "lossy" strip on au otherwise perfectly conducting plane surface is treated by an exact method employing elliptic wave functions. The calculations of the scattered fields of the strip by the two methods indicate the extent of the validity of the initial assumption in the approximate procedure.
A STUDY OF NUCLEON FORCES WITH REPULSIVE CORES: I. THE EFFECT OF CORES OF FINITE STRENGTH
Authors: Bird J. R. , Preston M. A.
Published: April 2011

A general study of nucleon potentials with repulsive cores has been made. In this paper, consideration is given to repulsions of finite strength and, for an exponential attractive potential and for the 1S n−p system, it is shown to what accuracy the core may be replaced by an infinite one with a smaller radius.
THE VISCOSITY OF LIQUID HELIUM II
Authors: Heikkila W. J. , Hallett A. C. Hollis
Published: April 2011

It has been found possible to use the rotating cylinder viscometer to measure the viscosity of liquid helium II between 1.13°K. and 2.18°K. provided that the fluid velocities do not exceed about 0.08 cm. sec.−1. The results, which are calculated directly from experimental observations and do not require any knowledge of the density of the normal component, can be made to fit the Landau and Khalatnikov theory for the temperatures below 1.8°K. for which the theory is applicable. The results are somewhat higher than the oscillating disk results above 1.4°K.
THE INITIAL OXIDATION OF NICKEL
Authors: Martius Ursula M.
Published: April 2011

This paper describes the first stages of oxidation of nickel. Under suitable experimental conditions small isolated crystallites are formed prior to the occurrence of a continuous oxide film. The shape, size, and number of the crystallites depends on the crystallographic orientation of the underlying metal. The specific features of the oxidation of grain boundaries are discussed and a tentative explanation of the observed phenomena is advanced.
DIURNAL VARIATIONS IN THE NUMBER OF SHOWER METEORS DETECTED BY THE FORWARD-SCATTERING OF RADIO WAVES: PART I. THEORY
Authors: Hines C. O.
Published: April 2011

Various observational factors affect the number of shower meteors which can be detected, in a given time interval, by the scattering of radio waves from the ionized meteor trails. The pertinent factors in the case of forward-scattering, where the transmitter and receiver are widely separated, are expressed approximately as functions of the position of the shower radiant. In combination, they provide an observational weight factor which may change appreciably as the radiant moves in the course of a day. The consequent diurnal variation in the occurrence of scattered signals may then be determined, and distinguished from variations due to random changes in the incidence rate of the meteors.
ON THE DETERMINATION OF ELECTROMECHANICAL COUPLING COEFFICIENTS IN A POLYRESONANT PIEZOELECTRIC VIBRATOR
Authors: Shaw E. A. G.
Published: April 2011

The well-known relationship between the electromechanical coupling coefficient and the separation (σ) of resonance and antiresonance frequencies requires modification where several significant modes occur within a small frequency interval. An expression is given for the "true" values of σ (i.e. those which would arise if each mode existed alone) in terms of the many moded system. The analysis neglects mechanical and electrical losses.
THE FISSION YIELDS OF ISOTOPES OF XENON AND KRYPTON IN THE NEUTRON FISSION OF U236 AND U238
Authors: Wanless R. K. , Thode H. G.
Published: April 2011

Several uranium samples have been irradiated under various conditions in the Chalk River N.R.X. reactor and in the Los Alamos fast reactor. The fission gases, xenon and krypton, have been extracted from the irradiated material and the relative isotopic abundances determined mass spectrometrically. Fine structure in the mass – fission yield curve has been found in both the xenon and krypton mass ranges for U235 + n and U238 + n fission. It is observed that this fine structure shifts to lower masses, as predicted, for neutron fission of U238. The proportions of U235 and U238 fission that have occurred in the irradiated samples have been estimated from the percentage change in fine structure.
THE PROTON COMPONENT OF COSMIC RAYS AT AIRCRAFT ALTITUDES
Authors: Ogilvie K. W.
Published: April 2011

Experiments with a heavy particle selector installed in an aircraft show that the proton intensity in the energy range 230 to 480 Mev. has a variation with height which is exponential, with absorption length 128 ± 10 gm./cm.2 The latitude effect between λ = 40°N. and λ = 56°N. is in general agreement with that found for fast (up to 5 Mev.) neutrons. Some information has been obtained on the variation of the average specific yield for primary energies below 5 Bev.
ON DIURNAL VARIATION IN COSMIC-RAY INTENSITY AT OTTAWA
Authors: Chatterjee S. D. , Bloom J. N.
Published: April 2011

Cosmic-ray data from a high pressure integrating ionization chamber, obtained at Ottawa, for 129 complete days during September 1950 to July 1951 are subjected to rigorous statistical analysis. The barometric coefficient is −0.19% per mm. of Hg for the period covered by this analysis. The results also indicate a physically significant 24-hr. wave in cosmic-ray intensity, with an amplitude of 0.12% of the total intensity, having its maximum at about 10.40 a.m. local mean time. The existence of the semidiurnal wave, however, is not physically significant.
THE RAMAN SPECTRUM OF ETHANE
Authors: Romanko J. , Feldman T. , Welsh H. L.
Published: April 2011

The rotational and rotation-vibrational Raman spectra of gaseous ethane at 1–3 atm. pressure have been photographed with a spectral resolution of approximately 1 cm.−1. Analyses of the rotational structures of the ν1 and ν2 totally symmetric bands were carried out; only the Q branch of the ν2 band was observed. The structures of the degenerate ν10 and ν11 bands were analyzed; however, no trace of ν12 was found. The structure of the ν10 band shows beyond doubt that the point group of the molecule is D3d. From the ν11+ν4 infrared band, and the ν11 Raman band, the value, 278.4 cm.−1, is deduced for the torsional frequency ν4.
END-FIRE ARRAYS OF MAGNETIC LINE SOURCES MOUNT ON A CONDUCTING HALF-PLANE
Authors: Hurd R. A.
Published: April 2011

Formulae are developed for the far-field radiation patterns of end-fire arrays of magnetic line sources mounted on the surface of a half-plane. Patterns have been plotted for a number of interesting cases. It is found that the Hansen–Woodyard optimum end-fire condition no longer holds when the array is near the edge of the half-plane. The theory seems to describe reasonably well the behavior of corrugated surface radiators embedded in a finite ground plane, providing the array is removed from the edge by a distance about equal to the array length.
GAMMA RADIATION FROM THE PROTON BOMBARDMENT OF BORON TEN
Authors: Chadwick G. B. , Alexander T. K. , Warren J. B.
Published: April 2011

The gamma rays resulting from the bombardment of B10 with protons of energies from 0.5 to 2.0 Mev. have been observed with a sodium iodide scintillation counter. Capture radiation, of energy[Formula: see text]showed a broad resonance at Ep = 1135 ± 15 kev. At this energy, the radiation had an angular distribution of the form 1 + (0.50 ± 0.05)cos2θ and a total cross section (3.5 ± 1.0)10−30 cm.2 Several lower energy radiations were also observed and assigned tentatively to cascade transitions in C11.The cross section for the 430 kev. radiation from the reaction B10(p, αγ)Be7 was found to be 0.21 ± 0.05 barn at Ep = 1.52 Mev. This radiation was found to be isotropic.
REFLECTION AND TRANSMISSION AT A SLOTTED DIELECTRIC INTERFACE
Authors: Collin R. E.
Published: April 2011

A theoretical analysis of a slotted dielectric interface is given for the case of a plane wave incident at an angle θi and polarized with the electric vector parallel to the slots. A variational solution yielding upper and lower bounds to the parameters of the equivalent circuit for the interface is given. A numerical example for a wave incident at an angle of 30° on a slotted dielectric with a relative dielectric constant of 2.56 at a wavelength of 3.14 cm. shows that the phase shifts introduced into the reflected and transmitted waves are of the order of 1°. Also the impedance transformation across the interface is just that due to the change in wave impedance. Such a slotted dielectric may be) used to match a microwave lens to free space. A theoretical calculation shows that the reflection coefficient does not exceed 5% for angles of incidence up to 30° in the wavelength range 3–3.28 cm. for a slotted section used to match a dielectric of relative dielectric constant 2.56 to free space. Without a matching section the reflection coefficient is 23% or more.
THE AXIAL-FLOW ERROR IN THE THERMAL-CONDUCTIVITY PROBE
Authors: Blackwell J. H.
Published: April 2011

In connection with the development of the thermal-conductivity probe the author has used a new boundary condition of Jaeger to find an expression for an upper limit to the axial-flow error in these devices. Unlike in previous attempts at this problem the short-circuiting effect of the probe material is taken into account.
STRUCTURE OF THE MASS INCREMENTS OF ISOTOPES
Authors: Baker Jr. G. A. , Baker Sr. G. A.
Published: April 2011

A simple, accurate formula for the atomic masses of all isotopes is developed on the basis of a simplified nuclear model. It is shown theoretically and empirically that a formula which is linear in A and whose coefficients depend only on N–Z with a term added for pairing effects accounts for the major portion of the structure in the present experimental data and predicts them with unexcelled accuracy.
A STUDY OF NUCLEON FORCES WITH REPULSIVE CORES: II. LOW ENERGY PROPERTIES, PARTICULARLY CHARGE INDEPENDENCE
Authors: Shapiro J. , Preston M. A.
Published: April 2011

The low energy properties of two-nucleon potentials with infinite repulsive cores have been studied by numerical calculations using an electronic digital computer. The consequences of assuming charge independence for the nuclear force in the 1S state have been examined by performing computations with several potential shapes for both the neutron–proton and proton–proton systems. It was found that this assumption severely restricts the possible potential shape. Charge independence occurs with the Yukawa potential for zero core radius. Potentials that are more singular at small distances than the Yukawa require larger core radii; less singular potentials are not charge independent.
FINITE DISPLACEMENTS IN RHEOLOGICAL BODIES
Authors: Scheidegger A. E.
Published: April 2011

The study of the behavior of continuous matter is basic in many disciplines, such as in various branches of engineering and in the study of the Earth's interior. Herein, it is evidently necessary to have a sufficiently general mathematical formalism to encompass the behavior of any type of material under any mechanical conditions. Customary "rheological" theories suffer from various drawbacks; they are either (i) restricted to too specialized "ideal" materials, or (ii) restricted to too special displacements, or (iii) restricted to too specialized mathematical representations. The present paper attempts to fill the need for a summary of the representations of the dynamics of arbitrary materials. The displacement within the continuous medium is described by three "co-ordinate" functions as functions of three "parameters" and of time. Extensive use is made of the fact that, insofar as the expression of any physical statement is concerned, "co-ordinates" and "parameters" are entirely equivalent. Formulas are deduced which enable one to express the boundary conditions, the equations of motion, and any chosen rheological condition in either parameter space or co-ordinate space. The notion of finite strain is scrutinized.
THE DURATION OF FORWARD-SCATTERED SIGNALS FROM METEOR TRAILS
Authors: Forsyth P. A. , Vogan E. L.
Published: April 2011

The durations of radio signals obtained by forward scattering from meteor trails have been determined by direct measurement, using moving chart, amplitude recordings. The recordings were made simultaneously at two frequencies and similar measurements were made on signals received over two transmission paths in western Canada. The durations of signals observed over an east–west path appear to be greater than those observed over a north–south path. The observed dependence of duration upon both wavelength and equipment sensitivity is compared with that found previously by McKinley for back-scattered signals. Effects similar to those found by McKinley are present in the forward-scatter data. The method used to record the signals makes possible a more detailed examination of these effects. While the dependence of duration upon equipment sensitivity seems to be in accord with the presently accepted theories of meteor scattering, the dependence upon wavelength is not yet completely understood.
NUCLEAR QUADRUPOLE RESONANCE SPECTRUM OF B11 IN KERNITE
Authors: Haering R. R. , Volkoff G. M.
Published: April 2011

The pure quadrupole resonance frequencies of B11 nuclei at two different sites (denoted by E and F) in a single crystal of kernite (Na2B4O7.4H2O) have been determined both by observing the B11 resonances in zero external magnetic field, and also by investigating their Zeeman splitting in magnetic fields up to 30 gauss. The values obtained are 1281.1 ± 2 and 1287.0 ± 1 kc./sec. for the E and F sites respectively. These frequencies agree within experimental error with the values 1286 ± 4 and 1287 ± 3 kc./sec. predicted on the basis of studies in a magnetic field of 7000 gauss. The agreement for the F site is much better than for the E site. These zero field resonances have also been observed in a polycrystalline sample. The observed weak field Zeeman splitting for the single crystal agrees very well with that calculated from high field data for F sites, but at present disagrees with the corresponding calculation for E sites. A Na23 pure quadrupole resonance in kernite has also been measured at 1560.0 ± 1 kc./sec. The second Na23 resonance expected from high field work has not been observed to date.
AN OPTIMUM PARAMETER BETA-RAY SPECTROMETER
Authors: Geoffrion C. , Giroux G.
Published: April 2011

not available
MEASUREMENT OF THE NEUTRON YIELDS FROM ACTINIDE–BERYLLIUM ALLOYS
Authors: Hanna G. C. , Runnalls O. J. C.
Published: April 2011

The neutron yields of a series of actinide–beryllium sources have been measured. Some of the sources were compared with primary neutron standards in a manganese sulphate bath. The experimental procedure is described in detail and corrections for the loss of neutrons from the bath are discussed. These measurements include a comparison of the Chalk River Ra-α-Be and the National Bureau of Standards Ra-γ-Be standard sources. The majority of the actinide–beryllium alloy sources were then compared with the standardized sources in simple boron trifluoride counter systems.
THE PHOTOPROTONS EMITTED FROM OXYGEN-16 NUCLEI
Authors: Livesey D. L.
Published: April 2011

The photographic plate method has been used to study photoprotons emitted from oxygen gas exposed to bremsstrahlung of maximum energies 30, 35, and 70 Mev. The proton energy distributions above 5 Mev. show maxima corresponding to peaks in the (γ, p) excitation function at 20.7, 21.9, and 24.0 Mev. The proton angular distributions are anisotropic, in general agreement with a sin2θ function, but the high-energy protons exhibit a degree of asymmetry about the 90° angle which may be due to a small electric-quadrupole interference effect.
THE ABSORPTION OF ULTRAVIOLET IONIZING RADIATION IN GASES
Authors: Bainbridge G. R. , Prowse W. A.
Published: April 2011

The sparking probability of a test gap, to which short-duration direct high voltage pulses are applied, is shown to depend on the distance of the gap from a source of short wavelength, ultraviolet radiation. The radiation is restricted to a small volume of gas midway between the electrodes. The sparking probability can therefore be used as a parameter in examining the absorption of the radiation responsible for triggering a discharge in the gas. Absorption of ultraviolet radiation by the gases argon, air, nitrogen, and oxygen has been studied.
ON A NEW THEORY OF MOUNTAIN BUILDING
Authors: Scheidegger A. E.
Published: April 2011

In recent years there has been a growing body of evidence indicating that continental drift might have occurred on a large scale. Without prejudicing the reality of such drift (which must be decided upon from factual evidence), this paper investigates the forces that might possibly have caused it. This leads to a new theory of mountain building. It is shown that continental drifting, as it is indicated by presently available evidence, might be explained by the assumption of a random drag force with a correlation time of 150 million years. It is possible, though not altogether likely, that this drag force might be the result of very large (radius 6000 km.) random convection currents. Their duration would also have to be of the order of 150 million years. The assumption of a random drag force does not necessarily contradict ideas maintaining that continental growth also took place; the two effects might well be superimposed upon each other.
CANADIAN STANDARD OF FREQUENCY
Authors: Kalra S. N. , Pattenson C. F. , Thomson M. M.
Published: April 2011

Over the past 3 years a frequency standard of very high precision has been installed in Canada. It is composed of equipment located in three different laboratories in Ottawa, Ontario, but separated by a few miles. Intercomparison of frequency between these laboratories, which is done by sending signals over telephone lines and related techniques, is briefly described. Results indicate frequency stability of about 2:1010 over short and long periods. Absolute frequency is determined from astronomical observations. International inter-comparison is carried out by phase measurement of standard frequency and by observations of time signals; some of the results are presented.
DIFFUSION IN MULTICOMPONENT METALLIC SYSTEMS: IV. A GENERAL THEOREM FOR CONSTRUCTION OF MULTICOMPONENT SOLUTIONS FROM SOLUTIONS OF THE BINARY DIFFUSION EQUATION
Authors: Kirkaldy J. S.
Published: April 2011

If C = C(x, y, z, Dt) is a solution of the binary diffusion equation[Formula: see text]for a given boundary condition, then[Formula: see text]where[Formula: see text]is a solution of[Formula: see text]for the ith component of an n-component system subject to the same formal boundary condition. As an example, the ternary diffusion field about an initial point source is calculated. The method of calculation for steady state and transient equilibrium is indicated.
DETERMINATION OF THE UNIT OF CAPACITANCE
Authors: Dunn A. F.
Published: April 2011

As part of the program to establish a wholly self-consistent group of basic electrical units for the country, the unit of capacitance maintained in the National Research Council has been determined in an absolute sense in terms of the frequency and resistance units maintained in the laboratories, with an accuracy comparable to that of the primary standards. The determination was made by connecting additional components to an existing capacitance and conductance measuring bridge to form a modified Wien bridge network. The results obtained indicate an accuracy of ± 0.0025%.
ON THE GENERAL PLANE PROBLEM OF PLASTICITY AND ITS GEOPHYSICAL SIGNIFICANCE
Authors: Das Sisir Chandra
Published: April 2011

The results obtained from the fault plane studies made in the Dominion Observatory show strong horizontal displacements in the focus of earthquakes. This indicates a marked deviation from the existing theories of geotectonics. To account mathematically for them, the study of the plane problem of plasticity is proposed using as yield condition a general functional relation between the stresses.The differential equations involved in the problem are of non-linear type. For solutions these are replaced by a different set of completely equivalent equations expressing variations along families of curves, known as characteristics, across which certain derivatives may be discontinuous under suitable boundary conditions.Physically, the elastic-plastic (or rigid-plastic) interface is taken as a characteristic curve which is a fundamentally unknown thing, and which must be ascertained from symmetry of the problem or by proper experimentation. Investigations in this direction are now being done in connection with the International Geophysical Year. Meanwhile here we discuss the various relatively modern methods of linearization of the stress equations. Each of them essentially deals with transformations of co-ordinates, depending upon the form of the yield condition, though in every case the generalized nature is maintained.
THE CALCULATION OF THE ELECTRIC POTENTIAL AND THE CAPACITY OF A TORE BY MEANS OF TOROIDAL FUNCTIONS
Authors: Loh S. C.
Published: April 2011

Expressions in terms of toroidal functions for the electric potential and the capacity of a tore with respect to infinity are derived. Some numerical calculations of the potential are presented for tores of different sizes in order to illustrate the derived results.The electric capacity of a tore is also calculated and the numerical results are compared with those of a sphere of radius a.
A NUCLEAR MAGNETIC RESONANCE STUDY OF COLEMANITE
Authors: Holuj F. , Petch H. E.
Published: April 2011

A single crystal of colemanite, CaB3O4(OH)3∙H2O, which is known to be ferroelectric at temperatures below about −2 °C, has been investigated by means of nuclear magnetic resonance (n.m.r.) techniques. The B11 resonances are split because the nuclear Zeeman levels are perturbed by the interactions between the nuclear electric quadrupole moments and the electric field gradients existing at the boron sites. The splittings have been examined in detail at room temperature and at −40 °C. The results have been analyzed and the quadrupole coupling constants, the asymmetry parameters, and the orientations of the principal axes of the electric field gradient tensors existing at the boron sites at room temperature and −40 °C are reported. Selected B11 resonance lines have been examined over the temperature range 40 °C to −120 °C with particular emphasis on the region about 0 °C where a phase transition occurs. The complex proton signal was also studied over the same temperature range. Abrupt broadening of this signal occurred at the phase transition. These studies revealed that the crystal may transform from its centrosymmetrical room-temperature (point group 2/m) form either to a metastable monoclinic form with point group 2 or to a triclinic form with point group 1. It is not clear whether two transitions, separated by only about 3 °C, are involved or whether there is only one transition with two alternative arrangements, differing only slightly in activation energy, available to the structure. The transition or transitions are of the second-order displacive type. Where possible, the results have been interpreted in terms of the crystal structure.
MAGNETO-OPTICAL ROTATION IN VERY HIGH FIELDS
Authors: Stevenson Richard
Published: April 2011

Magneto-optical rotation by transmission through or reflection from solids is examined by the classical free electron theory, with the view of taking such a measurement using fields in the megagauss range. In general the rotation is a markedly non-linear function of the magnetic field, and in some cases can change in sign as the field increases. For very low fields the rotation varies directly with B, but in the high field limit the rotation varies inversely with the field. For substances in which the intercollision time of the electron is small, measurements of the Kerr rotation (i.e. by reflection) will give the electron mobility as a function of the magnetic field, and thus will give important data which can be used in conjunction with high field magnetoresistance experiments.
INTENSITIES IN Σ–Δ AND Π–Δ TRANSITIONS OF DIATOMIC MOLECULES
Authors: Kovács I.
Published: April 2011

Explicit expressions are obtained for the intensity distribution in the branches of 1Σ–3Δ, 3Σ–3Δ, and 1Π–3Δ bands. They are valid with satisfactory accuracy for any value of the coupling constant of the 3Δ state.
THE CRACKING ACTIVITY IN ICE DURING CREEP
Authors: Gold L. W.
Published: April 2011

Observations were made at one temperature on the cracks that form in ice during creep under constant compressive load. The ice had a hexagonal symmetry with respect to the grain boundaries. The load was applied perpendicular to the long axis of the grains. A piezoelectric crystal was used to detect the cracking activity in the ice.Two stages of cracking were observed. The first occurred during the transient period of the creep, and the plane of these cracks tends to be parallel to the grain boundaries and to the direction of the stress. The rate at which these cracks formed decreased very markedly as the creep rate approached a constant value. Above a certain stress, the creep rate continuously increased with time. Under this condition the second stage of cracking was observed. These cracks tend to be more irregular in direction and to occur in planes that are at 45° to the applied stress.
DOMAIN STRUCTURE IN YTTRIUM IRON GARNET
Authors: Smith Archibald W. , Williams Gerald W.
Published: April 2011

The magnetic domain structure in thin slices of yttrium iron garnet crystals has been studied by transmitted polarized light. The transmitted light exhibits Faraday rotation and magnetic birefringence, and both effects have been used to observe the domain structure. An example of structure in samples having a growth face on one side is presented for each of the (110) and (112) planes. The structure for the (110) face is similar to that for an ideal sample in this plane. The structure for the (112) face differs from an ideal sample due to a large strain anisotropy.
DYNAMIC SIMILARITY OF INSTABILITIES OF DISPLACEMENT FRONTS IN POROUS MEDIA
Authors: Scheidegger A. E.
Published: April 2011

It has been observed that instabilities may occur when a fluid penetrates into a porous medium which contains another, more viscous fluid. The problem of describing these instabilities analytically is very difficult so that recourse has been taken to model experiments. In the present paper, the scaling relationships (dynamic similarity conditions) for the interpretation of such model experiments are derived, based upon a variety of theories of the instability phenomena.
THE EFFECT OF AN EXPLOSION IN A COMPRESSIBLE FLUID UNDER GRAVITY
Authors: Ross R. A.
Published: April 2011

In this paper an investigation is made of the effect of an axially symmetric explosion at any depth in a semi-infinite, compressible, non-viscous fluid, acted upon by gravity. The explosion is represented by a line source of the form δ(x)δ(z – h)δ(t), where h is the depth of the source. An exact solution is given using the linearized theory. This solution is studied in detail by asymptotic methods, for the special case of a surface explosion. It is found that compressibility results in the gravity waves being propagated with a speed less than c, the speed of sound in the fluid. If x is the distance from the explosion and t the time that has elapsed after the explosion, then for [Formula: see text] only "precursor" waves are noticed at the point of observation. For [Formula: see text] large amplitude waves are present, similar to the waves predicted by the incompressible theory.
THE APPLICATION OF A FLUXGATE MAGNETOMETER TO AN AUTOMATIC ELECTRONIC DEGAUSSING SYSTEM
Authors: Graham R. L. , Geiger J. S.
Published: April 2011

The three-component fluxgate magnetometer developed by Serson has been adapted to provide continuous correction signals to the degaussing system of the Chalk River iron-free β-ray spectrometer. Improved electronic circuitry has been developed for the magnetometer which minimizes the zero error and reduces to < 10−4 gauss long-term drift caused by component aging. The degaussing coil arrangement used to generate uniform magnetic field components opposite to those of the earth is indicated and the current regulation system is described briefly. The method in which the magnetometer correction signal is introduced into the current regulators is shown and an example is given of the performance of this degaussing system during a magnetic storm.
TWO-HOLE TWO-PARTICLE LEVELS IN Pb208
Authors: Pinkston William T. , True William W.
Published: April 2011

The energy levels of Pb208 arising from certain two-hole two-particle shell-model configurations have been predicted theoretically. It is concluded that only a few such levels are expected in Pb208 and all of them have energies greater than or about equal to 6 Mev. The closed-shell core was included in the J = 0+ energy matrix in order to get an estimate of the two-body correlations in the ground state. Only a few per cent of higher configurations is predicted for the ground-state wave function.
FOCUSING OF CHARGED PARTICLES IN A CYLINDRICALLY SYMMETRIC MAGNETIC FIELD PROPORTIONAL TO r−1
Authors: Lee-Whiting G. E.
Published: April 2011

The aberrations associated with skew trajectories lying near the midplane of a "flat"-type β spectrometer with a magnetic field falling off as r−1 have been surveyed over wide ranges of values of the field strength at the source and of the angle of emission; Lafoucrière (1950) showed that such a field possesses a perfect focus for midplanar orbits. A field strength has been found for which the aberrations corresponding to finite aperture are exceedingly small; with a point source it would be possible to get transmissions of 2.3% and 6.0% at resolutions of 0.01% and 0.1% respectively. The defocusing resulting from finite source-height has been studied for this particular value of the field strength and has been found to be large; the resulting permissible source-area is so small that the luminosity of the instrument is inferior to that of a π√2 spectrometer.Methods of producing fields varying as r−1 over a wide range of r have been investigated; both iron pole-pieces and iron-free coils have been considered.
CORRELATION BETWEEN INTENSITIES OF AURORAL ABSORPTION AND PRECIPITATED ELECTRONS
Authors: Jelly Doris H. , McDiarmid I. B. , Burrows J. R.
Published: April 2011

Particle detectors on the Alouette I satellite and on rockets have been used to study the correlation between the intensity of electrons with energies greater than 40 keV and the intensity of auroral radio-wave absorption. The average relationship between the intensity of precipitated electrons and the amount of absorption is in approximate agreement with that expected from theory. For the same electron flux a day-to-night absorption ratio of about a factor of two is suggested by the measurements.
ELECTRON PARAMAGNETIC RESONANCE EXPERIMENTS WITH Ti3+ IONS IN RbAl(SO4)2 ∙ 12H2O
Authors: Dionne Gerald F.
Published: April 2011

The paramagnetic resonance spectrum of the Ti3+ ion in cubic RbAl(SO4)2 ∙ 12H2O single crystals has been studied in the {100} and {110} planes at 4.2 °K with an X-band microwave spectrometer. The spectrum, which consists of a maximum of 12 lines, has been explained by considering a model of 12 magnetic complexes which are related to each other through the symmetry elements of the Th = (2/m)3 point group of the Rb alum lattice. For the spin Hamiltonian with [Formula: see text], three g factors have been determined—1.895, 1.715, and 1.767— within an accuracy of ±0.002, indicating the existence of a crystal electric field of orthorhombic symmetry.
MODIFIED HANSEN–WOODYARD CONDITION
Authors: Nagai Kiyoshi
Published: April 2011

Modified Hansen–Woodyard conditions for a continuous end-fire array of small dipoles are derived for two cases: (a) constant current amplitude distribution along the array; (b) a superposition of constant and attenuating current amplitudes along the array. The optimum phase velocity along the array for maximum gain in the end-fire direction is determined for these cases. In case (a) the directivity may be used to determine a theoretical maximum gain for a long end-fire array such as a long Yagi antenna, while the directivity in case (b) may be used to explain the experimental results obtained by Ehrenspeck and Poehler.
EXPERIMENTAL INVESTIGATION OF THE NM-64 NEUTRON MONITOR
Authors: Hatton C. J. , Carmichael H.
Published: April 2011

A comprehensive experimental study has been made of the NM-64 neutron monitor. The counting rate has been measured as a function of the thickness of the reflector, of the separation of the counters, of the thickness of the inner moderator, and of the gas pressure in the counters. It is shown that the figures given in the internationally approved specification represent a satisfactory optimization of the design. The counting rate of the NM-64 monitor is found to be 3.3 times that of an IGY monitor of the same horizontal area. The origin and movement of both fast and thermal neutrons within the monitor have been investigated using cadmium sheets and by studying events producing counts in more than one counter.
Periodic features of the statistical atom with exchange and correlation
Authors: Auluck F. C. , Jain Ashok , Kumar Satish
Published: April 2011

The periodic features of atoms are studied using a statistical model embellished with exchange and correlation. It is shown that the earlier results, obtained on the basis of the simple TF model, can be computed in an analytic form by using the Tietz approximation. Single-particle energy levels of neutral atoms are calculated following the approach outlined by us in an earlier publication (Jain and Kumar 1967), and are compared with those obtained by other methods. A new angular momentum assignment is proposed and is shown to give values of v(l, Z) (the number of electrons with orbital angular momentum quantum number l, in an atom of atomic number Z) which are in very close agreement with the empirical values. The relativistic mass–velocity correction is incorporated in the calculation of angular-momentum groups. Finally, some suggestions are made for improving the present formalism.
Inelastic collisions between excited alkali atoms and molecules, III. Sensitized fluorescence and quenching in mixtures of potassium with N2, H2, HD, and D2
Authors: McGillis D. A. , Krause L.
Published: April 2011

4 2P1/2–4 2P3/2 mixing in potassium, induced by collisions with N2, H2, D2, and HD, was studied using techniques of sensitized fluorescence. The potassium vapor-gas systems, in which the potassium vapor pressure was kept very low to avoid radiation trapping, was irradiated with one component of the resonance doublet. The fluorescence which contained both components of the doublet was monitored at right angles to the direction of excitation. The following cross sections for mixing and quenching were obtained from measurements of relative intensities of the fluorescent components. For K–N2 collisions: Q12(2P1/2 → 2P3/2) = 100 Å2, Q21(2P1/2 ← 2P3/2) = 66 Å2, Q10(2S1/2 ← 2P1/2) = 35 Å2, Q20(2S1/2 ←2P3/2) = 39 Å2. For K–H2 collisions: Q12 = 76 Å2, Q21 = 53 Å2, Q10 = 7 Å2, Q20 = 4 Å2. For K–D2: Q12 = 72 Å2, Q21 = 50 Å2, Q10 = 2 Å2, Q20 = 1 Å2. For K–HD: Q12 = 74 Å2, Q21 = 49 Å2, Q20 = 11 Å2, Q20 = 14 Å2. An analysis of these results suggests the presence of resonances with the molecular rotational levels.
Apparent poleward motion of onsets of auroral absorption events
Authors: Jelly Doris H.
Published: April 2011

A study is made of nighttime auroral radio absorption events observed by riometers in the latitude range of λ = 67–76°. Individual events are shown to extend over this range with a tendency to occur later at higher latitudes. If the observed onset delay time is interpreted as a poleward expansion of the disturbance, the corresponding average velocity is 0.8 km/s. This velocity is consistent with the poleward motion observed during visual auroral substorms. The absorption events are compared statistically with energetic electron events detected by the Alouette I satellite.
Local time asymmetries in the high-latitude boundary of the outer radiation zone for the different electron energies
Authors: McDiarmid I. B. , Burrows J. R.
Published: April 2011

Data obtained from the Alouette II satellite are used to examine various high-latitude boundaries of the outer radiation zone as a function of local magnetic time. Four different boundaries are defined and these are referred to as the 35-keV "background" boundary, the 35-keV "smooth" boundary, the 35-keV "sharp" boundary, and the 3.9-MeV "background" boundary. All of the boundaries show a marked dependence on local magnetic time. The 35-keV "smooth" and the 3.9-MeV "background" boundaries are identified with the stable trapping region and show a 1100–2300-hour asymmetry of about 3°. The 35-keV "background" boundary falls at higher latitudes than the other boundaries at all local times; a noon–midnight asymmetry of about 6° is observed as well as a marked dawn–dusk asymmetry. The 35-keV "background" boundary is tentatively associated with the boundary of closed geomagnetic field lines and it is suggested that there is a dawn–dusk asymmetry in the field configuration. The 35-keV "sharp" boundary is identified with the inner edge of the "cusp" region and its relation to the other boundaries is examined.