bluuebunny/crossref_metadata_2025 huggingface dataset:
RADIOACTIVE DECAY OF W188
Authors: Roy J. C.
Published: April 2011

The half-life of W188 has been measured to be 69.4 ± 0.5 days. The gamma radiations emitted in the decay of W188 have been studied with an NaI scintillation spectrometer, and the beta radiations by absorption in aluminum. Three gamma rays with energies of 0.290 ± 0.005, 0.227 ± 0.005, and 0.063 ± 0.005 Mev were observed. The intensities of these gamma rays were measured relative to those gamma rays from the daughter activity Re188. The W188 gamma intensities thus deduced are respectively 0.002, 0.001, and about 0.001 per disintegration. The 0.227 and 0.063 gamma rays are in coincidence. It logically follows from the gamma results that 99.3% of the beta radiations go to the ground state of Re188 with an energy of 0.36 ± 0.04 Mev (determined by Feather analysis), while about 0.4% go to an excited state at 0.290 Mev; an upper limit of 0.3% has been set for a beta transition to the 0.063 state. A decay scheme for W188 is proposed.
A STATISTICAL ANALYSIS OF THE BAROMETER COEFFICIENTS FOR COSMIC-RAY INTENSITIES
Authors: Lapointe S. M. , Rose D. C.
Published: April 2011

The data from all four Canadian cosmic-ray stations, Ottawa, Resolute, Churchill, and Sulphur Mountain, have been analyzed statistically with the help of an I.B.M. 650 computer over a period of three and a half years extending from the beginning of the I.G.Y. in July 1957 to the end of 1960. The barometer coefficients for triple and double coincidences in the international cubical telescope and for the nucleon intensity in the standard neutron monitor have been derived. A single correlation between intensity and pressure was used; two different ways of effecting this correlation were tried over a 6-month period. The results were compared and the best method was applied to the remaining three years. Monthly values were calculated, as were yearly values and also values for the 3-year period. The results reveal no significant seasonal variations in the barometer coefficients and no significant year-to-year variation. However, the seasonal fluctuations of the nucleon coefficient unsuspectedly follow those of the meson. A small latitude effect seems to be present. The nucleon coefficient at Sulphur Mountain, a high altitude station, is larger than the one at Ottawa (same geomagnetic latitude, sea level station).
THE PRODUCTION OF HIGH-ENERGY KNOCK-ON ELECTRONS AND BREMSSTRAHLUNG BY μ-MESONS
Authors: McDiarmid I. B. , Wilson Margaret D.
Published: April 2011

A multiplate cloud chamber experiment has been carried out to study the electromagnetic interactions of μ-mesons in iron and lead target materials. Energetic interactions which occurred inside the chamber were selected by an arrangement of plastic scintillators and Geiger counters; the total track lengths, and hence the energies, of the associated electron showers were measured by a photometric method combined with scintillator measurements. When Bremsstrahlung is the dominant process, the measured production probabilities are in good agreement for energy transfers in the range from about 8 to 40 Bev. When the production of knock-on electrons is the dominant process, good agreement with theory is obtained for energy transfers around 4.5 Bev but only fair agreement is obtained for higher energy transfers.
SOME OBSERVATIONS OF POLAR-CAP ABSORPTION IN THE NORTHERN AND SOUTHERN HEMISPHERES
Authors: Jelly Doris H. , Collins C.
Published: April 2011

The phenomenon known as polar-cap absorption (PCA) has been studied by several different radio techniques and some of the characteristics of the absorbing regions are now fairly well known. In the present study the deviations of minimum frequencies (Δƒmin), recorded by ionosondes at high-latitude Arctic and Antarctic stations, have been used synoptically to investigate the simultaneous occurrence of the absorbing regions in the northern and southern hemispheres. Detailed examination of these ionosonde data has revealed the occurrence of periods of weak absorption which have the characteristics of the large PCA events. Several of the PCA features such as starting times and durations are discussed and the morphology of one of the weak events is considered in some detail.
THE EFFECT OF ABSORPTION AND MULTIPLE SCATTERING ON RADIO-AURORAL OBSERVATIONS
Authors: Lyon G. F.
Published: April 2011

The apparently anomalous amplitude-frequency dependence sometimes observed during radio-auroral experiments is accounted for on the basis of absorption, or multiple scattering, or both. Auroral-type absorption as high as 25 db at 42 Mc/s is observed. Multiple scattering possibly up to fifth order at 104 Mc/s is also observed. On occasion both absorption and multiple scattering are operative simultaneously. Assessing the magnitude of these effects is important in separating amplitude-frequency dependence from radio-auroral data.
RADIO-AURORAL REFLECTION MECHANISMS
Authors: Lyon G. F. , Forsyth P. A.
Published: April 2011

The amplitudes of the backscattered signals from radio aurora at 42.00, 60.00, 82.00, and 104.00 Mc/s were studied using scaled, continuous-wave systems. Both weak scattering and critical reflection were observed, with critical frequencies up to 104 Mc/s. The experimental results are consistent with Moorcroft's proposal that the scattering region consists of an assembly of gaussoids having some distribution in size. The most frequently occurring size seems to correspond to a semiminor axis of approximately 1 meter. Fairly rapid variation of electron density with time was observed, suggesting that amplitude-frequency dependences derived from time-averaged results are of little value in understanding the scattering process.
FINITE STRAIN IN TECTONIC DEFORMATIONS
Authors: Scheidegger A. E.
Published: April 2011

An analysis is made of the mathematical means that are available to describe finite tectonic displacements. It is shown that, from field observations, the principal axes of a tensor can be found which is related to the strain tensor in finite strain theory. The trajectories of this tensor yield a graphic picture of the local deformations; if certain averages are calculated for the local deformation, the over-all regional displacement pattern can be established.
LIFETIME OF THE 3.85-MEV LEVEL IN C13
Authors: Simpson J. J. , Clark F M. A. , Litherland A. E.
Published: April 2011

The lifetime of the 3.85-Mev level in C13 has been measured by the Doppler shift attenuation method and has been found to be [Formula: see text] second. This lifetime together with the (9.3 ± 2.0) × 10−3 relative intensity of the E2 branch from this level implies a strength [Formula: see text] in Weisskopf units for this transition. It is also found that the primarily M2 transition to the ground level of C13 has [Formula: see text] and the E1 transition to the 3.68-Mev level has [Formula: see text]. The measured transition strengths are compared with recent theoretical calculations based upon the weak-coupling model.
PROPAGATION OF RANDOMLY PERTURBED FIELDS
Authors: Bourret R. C.
Published: April 2011

A preliminary account is given of an approximation method useful in the calculation of the ensemble mean value of a field subject to perturbation by, or interaction with, a stochastic field, where the stochastic field is characterized by its two-point (bilocal) autocorrelation function. The method consists of treating the perturbed field and quadratic terms in the perturbing field as statistically independent when they occur in a certain integral expression. This is called the hypothesis of local independence, and it amounts to regarding the stochastic field as having a negligible local effect on the perturbed field. Use of the method, according to a certain prescription given, results in an integrodifferential equation for the ensemble mean value of the randomly perturbed field. Dispersion relations are obtained with great facility through use of the method described.A diagrammatic representation is introduced which permits the visualization of the underlying processes of generalized scattering and which helps clarify the limitations of the hypothesis of local independence. Two examples are given: wave propagation in a medium with random scalar inhomogeneities, and turbulent diffusion.
STRUCTURE AND PROPERTIES OF UNCONSOLIDATED AGGREGATES
Authors: Naar J. , Wygal R. J.
Published: April 2011

An analysis of the arrangement of particles in unconsolidated aggregates allows the prediction of some of their properties such as porosity, permeability, and pore-size distribution. Experimental results obtained from systems of spherical beads and from a mixture of sands are in agreement with the theoretical predictions.
THE ELECTRONIC SPECTRA OF PF AND PF+
Authors: Douglas A. E. , Frackowiak M.
Published: April 2011

Five band systems of PF and one of PF+ have been excited in a discharge through PF3 and have been photographed with a high resolution spectrograph. The rotational fine structures of a number of bands of each system have been analyzed and the rotational and vibrational constants determined. The principal constants for a 3Σ state of PF, which is believed to be the ground state, are ωe = 846.75 cm−1, Be = 0.5665 cm−1, re = 1.590 0 Å.
SOME FEATURES OF THE RESPONSE OF NEUTRON MONITORS TO LOW-ENERGY PARTICLES INCIDENT ON THE TOP OF THE ATMOSPHERE
Authors: Webber William
Published: April 2011

By comparing the measured intensities and spectra of solar particles at the top of the atmosphere with measured neutron monitor intensity increases at sea level for several solar particle events, a set of yield functions has been derived for these neutron monitors in terms of low-rigidity (0.5–2 BV) particles incident on the top of the atmosphere. The monitors are found to be significantly more sensitive to these low-rigidity particles than has recently been believed. Various characteristics of the response of neutron monitors to solar flare particles are discussed. In particular a method is described by which the intensity increase vs. latitude curve for the neutron monitors during these events can be utilized to derive a measurement of the deviations in geomagnetic cutoff from those expected from the earth's internal field only. Applying this to the November 15, 1960, event suggests that a ring current of moment M = 0.6 ME and radius R = 7.7 RE was flowing at 1130 U.T. on this day.
WAVE PROPAGATION AROUND A CURVED BOUNDARY WHICH CONTAINS AN OBSTACLE
Authors: Wait James R.
Published: April 2011

The problem is to calculate the field of an electric dipole on a smooth spherical or cylindrical surface which contains a localized obstruction. An approximate solution is obtained by combining the rigorous theory of diffraction by a sphere and the approximate Kirchhoff diffraction theory for black screens. The application to ground wave propagation is briefly indicated.
ROTATIONAL ANALYSIS OF THE VISIBLE BAND SYSTEM OF THE BiF MOLECULE
Authors: Rao T. A. Prasada , Rao P. Tiruvenganna
Published: April 2011

A rotational analysis of five bands, (1,0), (0,0), (0,1), (0.2), and (0,3), of the visible band system A of BiF has been carried out by photographing the bands under high dispersion (1.25 Å/mm). The analysis has shown that the bands arise from a 0+(3Σ−)–0+(3Σ−) transition. The rotational constants for the upper and lower states of the system are obtained.
IMPACT THEORY OF RAMAN LINE BROADENING
Authors: Fiutak J. , Kranendonk J. Van
Published: April 2011

The impact theory of Anderson for the pressure broadening of absorption and emission spectra is extended to the Raman spectra. Expressions are derived for the line shape and the optical cross sections in the classical path approximation. The central problem is the calculation of the average value of the evolution operator of the molecular system. It is shown that a simple derivation of the usual impact formula for this average value is obtained by averaging over all collisions as well as over all collision times. The perturbations of the intermediate states of the radiation processes are of importance only for resonant Raman scattering and may be neglected for non-resonant scattering. For freely rotating molecules the Raman scattering arising from electric dipole interaction can be decomposed into "isotropic", "magnetic dipole", and "electric quadrupole" scattering, corresponding to the j = 0, 1, and 2 irreducible parts of the Raman tensor. The optical cross sections for these three types of Raman scattering are different and are given by the reduced matrix elements, corresponding to j = 0, 1, and 2, of the optical cross-section operator, where j is the sum of the angular momenta in the initial and the complex conjugate of the final state of the radiation process.
SPATIAL VARIATIONS IN GEOMAGNETIC MICROPULSATIONS
Authors: Duffus H. J. , Kinnear J. K. , Shand J. A. , Wright C. S.
Published: April 2011

Micropulsation fields measured simultaneously at pairs of stations are compared in order to describe their recognizable geographical extent and the perturbations due to local terrain. Some characteristics of coastal and inland sites are shown. The micropulsation field gradients were too small to be measured over a homogeneous earth but were clearly evident near the seacoast. Estimates are made of the extent of the anomaly at the seacoast, and of the fraction of the signal accounted for by geology of the site. Separations between sites range from 1 km up to 1750 km. The distribution of the micropulsation amplitude in different directions and its dependence on period are shown for each site. Its correlation with Kp is also shown.The data refer only to regular micropulsations of period from about 500 seconds down to 2 seconds, observed simultaneously at pairs of stations situated in mid-latitudes.
ON HOUSTON'S METHOD OF EVALUATING INTEGRALS OVER THE BRILLOUIN ZONE: NORMALIZATION FACTOR IN A SIMPLE CUBIC LATTICE
Authors: Ganesan S. , Srinivasan R.
Published: April 2011

In evaluating integrals over the Brillouin zone by Houston's method, a normalization factor has to be used. A wave-vector-dependent normalization factor nj(q + Δq/2) is calculated by equating the volume common to a spherical shell of radius q and thickness Δq and the simple cubic Brillouin zone to the expression given by a j-direction Houston method. Some sample integrals are evaluated using this (GS) normalization procedure and Horton and Schiff's (HS) normalization procedure, originally developed for face-centered cubic lattices. The superiority of the GS method, especially with highly anisotropic functions, is demonstrated. From an evaluation of the moments of the frequency distribution function in a simple cubic lattice for various values of the anisotropy parameter, it is concluded that, when high accuracy is desired, the GS procedure is applicable over a wider range of anisotropy parameter than the HS procedure. The θ–T curve calculated by using the correct normalization procedure in a simple cubic lattice is in good agreement with that calculated by Blackman's method.
WAVES IN WARM QUIESCENT PLASMAS
Authors: Johnston T. W.
Published: April 2011

In this work the comparison is made between the analyses of waves in a plasma which use perturbation theory, the Cartesian tensor or spherical harmonic expansion, and the integrated velocity moment equations. When the wave phase velocities are much greater than the average particle thermal velocities and when collision frequency is independent of velocity, then to first order in thermal transport terms, the three approaches give the same answer for plane waves, except for the phenomenon of Landau damping. Neglecting such damping and remembering the restriction on phase velocity, the use of integrated moment equations can then be justified in attacking non-planar wave problems.First-order relativistic effects are also considered.
MACROMOSAIC STRUCTURES IN DILUTE TIN ALLOYS
Authors: Hunt M. D. , Smith R. W.
Published: April 2011

The manner in which the striation and cellular substructures coexist during solidification was examined in dilute alloys of tin with lead and tin with antimony. Observation of solid–liquid interfaces produced by decanting the liquid from growing crystals showed that when both structures occurred simultaneously, striation boundaries lay within cell wall grooves as a result of the topography of the interface, and that they subsequently adopted a configuration which depended on the solute redistribution occurring during freezing. In the case of the tin–lead system, little striation boundary migration from cell walls was observed whilst considerable migration was found when antimony was the solute. This is attributed to the much higher local concentrations of lead than of antimony.
ICE ADHESION
Authors: Jellinek H. H. G.
Published: April 2011

Results of shear tests for the system ice – stainless steel and ice – optically flat fused quartz as a function of the rate of shear and roughness of the steel surfaces are presented. The adhesive strength decreased with decreasing roughness of steel surfaces, and the force versus time curves for smooth steel plates resembled those of two solids sliding over each other with a liquid layer between them. This behavior was especially evident in the case of the optically flat quartz. The adhesive strength as a function of rate of shear was linear for both ice – stainless steel and ice – quartz but there were indications of yield values. The results agree with the assumption of a liquidlike layer on ice. Ratios of viscosity coefficient to layer thickness were evaluated for both systems, and viscosity coefficients are estimated. Shear experiments on thin water films between glass plates support the assumption of a liquidlike layer on ice. The importance of interfacial free energy considerations is pointed out.
CHANGES IN THE INTENSITY LEVEL OF COSMIC RAYS AT FOUR STATIONS IN CANADA
Authors: Katzman J. , Rose D. C.
Published: April 2011

The mean annual intensity of the nucleon and meson components of the cosmic-ray intensity at Ottawa, Churchill, and Sulphur Mountain was at a minimum for the year September 1957 to August 1958 when the mean annual intensity of the 10.7-cm radio solar flux was at a maximum and the annual mean of the interplanetary magnetic index Kp was at its first maximum since the low at the beginning of the present solar cycle. At Resolute Bay the mean annual intensity of the nucleon and meson components was at a minimum for the year July 1959 to June 1960 when the interplanetary magnetic index Kp was at a second maximum. The anomalous behavior at Resolute Bay is attributed to a combination of spectral differences and directional effects.
THE INTERPRETATION OF THE ANGULAR DISTRIBUTION OF GAMMA RAYS FROM ASSEMBLIES OF ORIENTED NUCLEI
Authors: Daniels J. M. , Cotignola J. M.
Published: April 2011

The problem of how to deduce, from the angular distribution of emitted γ-rays, the properties of a system in which radioactive nuclei are oriented is considered. A scheme is proposed for measuring an arbitrary angular distribution and for finding the axes which give the simplest description of this distribution. The permissible forms for the Hamiltonian of the nuclei are discussed. Relationships are deduced between the symmetries of the angular distribution of γ-rays, the crystal structure, and the various terms in the Hamiltonian.
SUSCEPTIBILITY OF IRON GROUP COMPOUNDS IN HIGH MAGNETIC FIELDS
Authors: Stevenson Richard
Published: April 2011

Experimental studies of the magnetic susceptibility of NiCl2, CrCl3, CoCl2, FeSO4, CoSO4, CoSO4∙7H2O, Cr2O3, MnBr2, MnCO3, MnSO4, MnSO4∙H2O, and MnO2 measured with fields up to 500,000 oersteds are presented. The first eight substances show constant susceptibilities in the experimental region, whereas the last four show increases of varying size. The increases can be correlated to a certain extent with low field properties, and the hypothesis is put forward that they are due to a change in stability of the paramagnetic substances involving an alteration of the exchange coupling.
NICKEL-RICH SOLID SOLUTIONS IN BINARY ALLOYS WITH TIN, GERMANIUM, AND SILICON
Authors: Klement Jr. W.
Published: April 2011

By rapidly cooling liquid alloys, single-phase nickel-rich solid solutions have been obtained to [Formula: see text] at.% tin, ~20 at.% germanium, and [Formula: see text] at.% silicon. The lattice parameters measured for the metastable structures as well as for some alloys within the equilibrium single-phase region suggest linear variations with solute content, with slopes (in units of 10−3 Å/at.% solute) of +8.5 for tin, +1.94 for germanium, and −0.55 for silicon.
A GENERALIZED ROTATION–VIBRATION MODEL FOR DEFORMED EVEN NUCLEI
Authors: Williams S. A. , Davidson J. P.
Published: April 2011

The generalized rotation–vibration interaction problem for deformed even nuclei whose surface can be well represented by a single order spherical harmonic Yλ,μ has been solved for all λ. The conditions which allow the resulting Schrödinger equation to separate into rotation and vibration parts is stated and approximate solution for the latter is given which depends upon the rotational energy eigenvalues, [Formula: see text]. A graphical method for obtaining the energy eigenvalues of the interacting system for all values of λ is developed which is accurate to about 1% and is applied to the positive and negative parity levels of Th288. A table of the [Formula: see text] for [Formula: see text] necessary for the negative parity calculations is appended.
STRUCTURE OF THE BAND SPECTRUM OF CuCl MOLECULE: IV. ROTATIONAL STRUCTURE OF THE D AND E SYSTEMS OF Cu65Cl35
Authors: Rao P. Ramakoteswara , Brody J. K. , Asundi R. K.
Published: April 2011

The D and E band systems of Cu65Cl35, lying in the region 3900–4700 Å, have been photographed in emission under high resolution and rotational analysis of the (3,1), (2,0), (1,0), (0,0), and (0,1) bands of the D system and the (4,1), (3,0), (2,0), (1,0), (0,0), and (0,1) bands of the E system has been made. It has been assumed in the analysis that the D and E systems involve transitions 1Π (D1Π)−X1Σ and 1Σ (E1Σ)−X1Σ respectively. Fairly large Λ-doubling is observed in the D1Π state. Certain features in the E(0,0) band, which are not well understood, have been pointed out. The principal molecular constants obtained for the initial states of the D and E systems of Cu65Cl35 are as follows (cm−1):[Formula: see text]
DISTORTION OF THE TRITON CORE IN THE HYPERNUCLEUS ΛH4
Authors: Roth C. , Sharp R. T.
Published: April 2011

The Λ-nucleon potential effective in ΛH4 is estimated by means of a wave function which allows the nuclear core a radial expansion and a spheroidal distortion correlated with the instantaneous Λ-core distance. The inclusion of such distortions reduces by about 13% the Λ-nucleon potential required to fit the observed binding energy.
OPTICAL ABSORPTION SPECTRA OF ARSENIC AND PHOSPHORUS IN SILICON
Authors: Bichard J. W. , Giles J. C.
Published: April 2011

The optical absorption spectra of arsenic and phosphorus donor impurities in silicon have been studied under conditions of improved resolution. Absorption lines due to transitions from the impurity ground state to the excited states 2p0, 2p±, 3p0, 3p±, 4p0, 4 p±, and 5p0, and 5p± have been observed at 4.2° K. The relative intensities of some of these absorption lines are compared with existing experimental and theoretical estimates. The contribution of instrumental broadening to the observed line widths is assessed and natural line widths are estimated. The estimates indicate values for the natural line widths which are much less than those previously reported. For phosphorus impurity, the natural line widths are estimated to be less than 0.08 × 10−3 electron volts full width at half-maximum. The possibility of concentration broadening is discussed in connection with the arsenic data.
SIMPLIFICATION IN FINDING THE ALLOWABLE REPRESENTATIONS OF SPACE GROUPS
Authors: Raghavacharyulu I. V. V. , Bhavanacharyulu I.
Published: April 2011

A simplification in finding the allowable representations of the groups of typical wave vectors of a space group is considered, which makes use of the symmetry of the first Brillouin zone of the space group. By this method, one also obtains the compatibility relations of the allowable representations of the space group as a by product.
THE POSSIBILITIES FOR GAS DENSITY GAUGING BY SINGLE SCATTERING OF ELECTRONS
Authors: Falckenberg H. R. , Schumacher B. W.
Published: April 2011

The sensitivity of a gauge using single scattering of electrons is calculated, as well as the pressure range where it can usefully be employed. For a primary electron beam of between 30 and 100 kev and 100 μa, the calculated pressure range is found to cover about 12 orders of magnitude with a low limit of approximately 10−13 torr dependent on the geometry of the gauge. For beta rays, the useful range is less and the lower limit is likely to be near 10−6 torr. The upper limit of the gauge will be more than one atmosphere if multiple scattering and attenuation are also utilized, no change in gauge structure being necessary. If applied practically as an altimeter in the free atmosphere, the gauge with beta source would give a continuous record of density up to about 100 miles.
THE RAMAN SPECTRUM OF ETHANE-d6
Authors: Lepard D. W. , Sweeney D. M. C. , Welsh H. L.
Published: April 2011

The Raman spectrum of C2D6 at 1 atm pressure was photographed with a spectral resolution of ~ 0.4 cm−1. Of the six Raman-active fundamentals, v1, v2, v3, v10, and v11 were observed, and the rotational structures of v2, v3, and v10 were analyzed. The structure of v10 confirms the D3d model for the molecule and the analysis gave A0 = 1.3416 cm−1. This value, along with recent infrared values of B0 for C2H6 and C2D6, gives r0(C—H) ≡ r0(C—D) = 1.0914 ± 0.0003 Å, r0(C—C) = 1.5362 ± 0.0005 Å, and [Formula: see text].
RYDBERG ABSORPTION SERIES OF N2
Authors: Ogawa M. , Tanaka Y.
Published: April 2011

The absorption spectrum of N2 in the 600–1000 Å region, particularly the Rydberg series, has been reinvestigated with a grazing incidence spectrograph with a 6.8-meter concave grating.Worley–Jenkins' Rydberg series which converges to the [Formula: see text] state of [Formula: see text] was extended to m = 31. It is suggested that the doublet character of this series is due to the two electronic transitions whose upper states are 1Πu and [Formula: see text] given by the electron configurations:[Formula: see text]and[Formula: see text]respectively.Eight Rydberg series, including Worley's third series, were observed in the region between 710 and 950 Å. These series are divided into two groups, each consisting of four vibration series, ν′ = 0, 1, 2, and 3, with one converging to the A2Πu, 1/2 state and the other to the A2Πu, 3/2 state of [Formula: see text]. The upper electronic states of these two groups are assigned as 1Πu and 3Πu states given by the electron configuration:[Formula: see text]Hopfield's Rydberg series which converges to the [Formula: see text] state of [Formula: see text] was extended to m = 21, and in addition, one vibration series (ν′ = 1) was newly observed. The upper electronic states of the series are assigned as [Formula: see text] states, given by the configuration:[Formula: see text]Another absorption series, which is accompanied closely by the Hopfield emission series, was also observed and the upper electronic states of the series are assigned as [Formula: see text] states, given by the configuration:[Formula: see text]
IONOSPHERE LAYER TILTS AT OTTAWA, CANADA
Authors: Burtnyk N. , McLeish C. W. , Wolfe J.
Published: April 2011

A comparison of E- and F-layer tilts is made with previously published results. Both E-layer and night F-layer tilt variances are significantly higher even when known storm periods are eliminated. Some observations on unstable F modes are also reported.
SOME COMMENTS ON THE STATISTICAL MECHANICS OF IRREVERSIBLE PROCESSES IN GASES
Authors: Balescu R.
Published: April 2011

The objections formulated by Wu against the theory of irreversible processes developed by Prigogine and the author are discussed and shown to be incorrect.
THE APPROACH TO PARAMAGNETIC SATURATION
Authors: Stevenson Richard
Published: April 2011

The process of paramagnetic saturation in real substances is considered by means of the molecular field method and by Smart's elaboration of the Oguchi method. The magnetic moment and short-range order parameters are calculated as a function of the external field. Some qualitative rules are obtained which describe general tendencies toward saturation. The possibility arises that paramagnetic materials in high fields may change into a state of greater stability by altering their exchange couplings.
THE MULTIPOLE EXPANSION IN QUANTUM THEORY
Authors: Fiutak J.
Published: April 2011

The Hamiltonian of a system of charged particles interacting with the electromagnetic field is investigated. For an arbitrary system the multipole expansion of the interaction between the system and the field is derived by means of a suitable canonical transformation. The transformed Hamiltonian is obtained from the Hamiltonian of the system by replacing the momenta by the transformed kinetic momenta and by adding to the Hamiltonian a term representing the interaction of the system with the electric component of the field. By expanding this interaction term, as well as the transformed momenta, in powers of the dimension of the system over the wavelength, the multipole expansion of the Hamiltonian is obtained. For a system interacting with a classical field the multipole form of the Hamiltonian is exactly equivalent to the original Hamiltonian. For a quantized field this is not true, and the multipole form of the transformed Hamiltonian is shown to be equivalent to the original Hamiltonian only for first-order radiation processes.
OPTICAL FARADAY ROTATION STUDIES OF PARAMAGNETIC RESONANCE IN NEODYMIUM ETHYLSULPHATE
Authors: Rieckhoff K. E. , Griffiths D. J.
Published: April 2011

The magneto-optical Faraday effect was used to measure the saturation of the spin levels in concentrated neodymium ethylsulphate in both steady-state and pulsed microwave resonance experiments at liquid helium temperatures. The steady-state experiments yielded the paramagnetic resonance spectrum consisting of a main triplet and an extensive hyperfine structure. The line positions are explained in terms of the known spin Hamiltonian of the diluted salt and spin–spin interaction between nearest neighbors. An asymmetry of the line shape was observed for sufficiently low temperatures in qualitative agreement with existing theories. Measurements of saturation s versus microwave power P at constant field and temperature were made and yielded the relationship [Formula: see text] for s > 10%. The steady-state experiments also revealed the existence of a spatial gradient in the saturation across the sample.The pulsed experiments gave the spin–lattice relaxation time τ as a function of magnetic field H at various temperatures. At 4.2 °K, τ was found to be independent of H and of the order of 11 msec for fields from 800 to [Formula: see text], while at temperatures below 2 °K, τ was found to be strongly field-dependent, indicating the importance of cross-relaxation effects at temperatures [Formula: see text].
SPACE TIME IN THE HUND GRAVITATIONAL THEORY
Authors: Chambers Ll. G.
Published: April 2011

The metric associated with the Hund gravitational theory is obtained and compared with other metrics.
THE DECAY OF Pm151
Authors: Burke D. G. , Law M. E. , Johns M. W.
Published: April 2011

The radiations from Pm151 have been studied by external and internal conversion measurements and electron–electron, electron–beta, electron–gamma, and beta–gamma coincidence experiments. Thirty-six transitions have been identified. A decay scheme incorporating 30 of these has been established by energy and coincidence measurements with levels in Sm151 at 0, 0.0048, 0.0658, 0.0697, 0.0915, 0.1048, 0.1677, 0.1684, 0.2090, 0.3239, 0.3449, 0.4445, 0.741, and 0.821 Mev. The half-life of the 0.0048-Mev level is (19 ± 10) × 10−9 sec. The total decay energy is 1.195 ± 0.010 Mev.
THE DIFFUSION OF LITHIUM IN TUNGSTEN
Authors: Love H. M. , McCracken G. M.
Published: April 2011

The diffusion of Li7 through tungsten at temperatures around 1500° K has been measured. The diffusion process can be represented by a diffusion coefficient D = D0 exp(−e/kT), where e is 1.8 ± 0.2 ev, D0 = 5 cm2 sec−1, and T is the absolute temperature.
DYNAMIC SIMILARITY IN GROUNDWATER FLOW WITH A FREE SURFACE
Authors: Scheidegger A. E.
Published: April 2011

The scaling relationships applicable for the construction of laboratory models representing groundwater flow with a free surface are deduced. It is found that, for large length reductions, these scaling relationships are very difficult to satisfy. The scaling relationships, however, can generally be used for transferring results from small-scale systems (such as drainage ditches) to large-scale systems (such as river valleys). However, if one is willing to allow a small error by assuming that the boundary conditions may be correctly scaled if the pressure at the free surface in the prototype and in the model is taken as zero, much simpler scaling relationships can be obtained, which can be easily satisfied in practice.
THE FREEZING POINTS OF HIGH-PURITY METALS AS PRECISION TEMPERATURE STANDARDS: VII. THERMAL ANALYSES ON SEVEN SAMPLES OF BISMUTH WITH PURITIES GREATER THAN 99.999 + %
Authors: McLaren E. H. , Murdock E. G.
Published: April 2011

An investigation has been made of the freezing and melting temperatures of seven samples of high-purity bismuth (analyzed impurity contents <0.5 to 7 ppm) including zone-refined metal. Using a controlled outside nucleation technique, freezing curves having plateaux of essentially constant (< ±0.0001 °C) temperature with long durations are readily obtained. A standard deviation in plateau temperature (liquidus point) of ±0.00025 °C was obtained from a series of 34 freezes on a particular sample. The pressure effect on the freezing temperature of bismuth was determined as −0.0035 °C for 1 atmosphere. A value of 271.375 °C (Int. 1948) was determined for the standard liquidus point of pure bismuth.The liquidus points of the samples were intercompared with a precision of about 0.0002 °C and their alloy melting ranges were measured for selection of the purest samples. Ingot morphologies and solute redistributions during melting and freezing were investigated using decanting, quenching, and tracer techniques.Appendix I gives the results of the latest intercomparison of temperatures realized in a grid of water triple-point cells that is maintained by this laboratory for use in the precision temperature measurements. Appendix II lists the values and pressure–temperature dependencies of the liquidus points of the purest samples of Zn, Pb, Cd, Bi, Sn, and In that have been determined at this laboratory.
THE ABSORPTION SPECTRUM OF THE Si2 MOLECULE
Authors: Verma R. D. , Warsop P. A.
Published: April 2011

Three band systems of Si2 have been found in absorption with a flash photolysis apparatus. Two of the band systems at 3200 and 2100 Å are new, whereas the third is an extension of the 3Σ–3Σ system observed by Douglas in emission. All three systems have the same lower state and arise from [Formula: see text] transitions. It is very probable that the [Formula: see text] state is the ground state of the Si0 molecule. Rotational and vibrational constants of all four 3Σ states have been determined. The dissociation energy of Si2 is estimated to be 3.0 ± 0.2 ev.
ON THE ABSORPTION SPECTRUM OF H2O AND D2O IN THE VACUUM ULTRAVIOLET
Authors: Johns J. W. C.
Published: April 2011

The spectra of normal and heavy water vapor have been observed under high resolution in the region 1220–1240 Å. One band of H2O and two bands of D2O have been measured and analyzed. The spectra were taken in the ninth order of a 35-ft concave-grating spectrograph and the accuracy of measurement of the sharper lines is estimated to be about ± 0.005 Å. The results of the analyses are summarized below.[Formula: see text]These bands have been assigned as belonging to the first member of one of the two np Rydberg series.
PHOTOELECTRIC INTENSITY MEASUREMENTS UPON BANDS OF THE SiN (B2Σ+−X2Σ+) SPECTRUM
Authors: Stevens Anne E. , Ferguson H. I. S.
Published: April 2011

The SiN B2Σ+−X2Σ+ (3800–5200 A) spectrum was excited by continuous introduction of SiCl4 in trace amount into the afterglow produced by microwave excitation of nitrogen. Relative intensities of 21 bands were measured photo-electrically and interpreted with the aid of Franck–Condon factors qν′ν″ and r-centroids [Formula: see text] in terms of the variation of the electronic transition moment Re(r) with internuclear separation r. It was found that Re(r) could be represented empirically by Re(r) = const.(1−1.27r + 0.412r2), [Formula: see text].
RATIO AND ABSOLUTE BRIGHTNESS MEASUREMENTS OF THE SODIUM D LINES IN THE TWILIGHT GLOW
Authors: Zwick H. H. , Shepherd G. G.
Published: April 2011

Simultaneous measurements of the ratio and absolute brightness of the sodium D lines in the twilight glow have been made with a Fabry–Perot spectrometer. The atomic sodium abundance can be obtained from either of these quantities alone, using the resonance scattering calculations made by others. It was expected that simultaneous measurements of these quantities would provide a good test of the theory and its assumptions. Unfortunately, one experimental parameter is not precisely known; the ratio of the amounts of exciting radiation at the bottom of the solar D1 and D2 lines. With a suitable choice for this parameter, satisfactory agreement between the calculations and the measurements was obtained. In particular, the results reported here do not support the recent suggestion that the sodium abundance on the day side of the earth is usually much larger than in the twilight region.
LONGITUDINAL WAVES IN AN INHOMOGENEOUS MAGNETIC FIELD – PLASMA INTERFACE BASED ON THE WKB APPROXIMATION
Authors: Shkarofsky I. P.
Published: April 2011

Longitudinal perturbations are investigated which propagate in an inhomogeneous interface or transition boundary layer, from a plasma region where no magnetic field exists well within its interior, to a static magnetic field region from which the plasma is excluded. The inhomogeneity in this boundary layer is the prime inhomogeneity considered here. A WKB solution is obtained for waves whose wavelength is small compared with the equilibrium characteristic length. The component of the propagation wave number is assumed to vary in the direction in which the interface is inhomogeneous. From the zero-order solution it is shown that this wave number satisfies the same relation with the frequency of perturbation and velocities of the electron and ion beams, as that obtained in counter-streaming of an electron-plus-ion beam against another electron-plus-ion beam in a uniform medium. The first-order solution yields the manner in which the amplitude of the wave varies from point to point in the plasma interface. The physical significance of these modes and the time and space variation of these waves will be discussed. It is shown that the WKB solution is valid in the sheath up to quite small distances from the sheath boundary. Under certain conditions, a wave can exist which increases exponentially in time and whose amplitude increases towards the boundary. The problem of joining the WKB solution appropriately to a perturbed solution outside of the boundary is discussed.
THE ABSORPTION OF HIGH-ENERGY RADIATION, A MONTE CARLO STUDY: I. RECTANGULAR GEOMETRY
Authors: Steenberg N. R. , Iterson W. Van
Published: April 2011

As part of an investigation of the scattering of high-energy radiation by nuclei a Monte Carlo study has been made of the attenuation of radiation by a rectangular barrier composed of a moderately dense random array of rigid semiopaque spheres. It is found that the attenuation is much more rapid than that predicted by the rare-gas formula usually assumed and is well described by an alternative formula which is derived on probabilistic grounds. A corollary is that an effective cross section which is substantially larger than the free cross section must be assumed inside such a medium.
THE ABSORPTION OF HIGH-ENERGY RADIATION, A MONTE CARLO STUDY: II. SPHERICAL GEOMETRY
Authors: Steenberg N. R.
Published: April 2011

The absorption of radiation in a spherical obstacle composed of rigid spheres has been studied. The result is the absorption cross section of such an obstacle as a function of the free cross section and the number A of the individual spheres and of packing density. It is found that the usual rare-gas formula represents the cross section adequately. The analysis is applied to nuclear data for the absorption of 25-Bev/c protons by nuclei. It is found that for a nuclear radius R = r0A1/3 + δ, where δ is the radius of the nucleon, r0 = 1.17 fermi, δ = 1.05 fermi, and an average nucleon transparency a2 = 0.30 is consistent with the data.
VARIATIONS IN METEORIC RADIO SIGNAL DECAY RATES
Authors: Rice D. W. , Forsyth P. A.
Published: April 2011

The rate of decay of the radio signal reflected from an underdense meteor trail is usually considered to be a simple function of trail height. In fact a large scatter is found in decay rates measured by means of radar or backscatter observations and this dispersion persists for forward-scatter measurements, where the decay rates can be measured with greater precision. The scatter persists even for measurements made at different radio frequencies on the same trail. The results of calculations are presented which indicate that the observed degree of variation in decay rates could result from nonuniformities in the trail ionization.
NEUTRON SEPARATION ENERGIES FOR ZIRCONIUM AND THE Zr96–Nb96 AND Nb94–Zr91 DECAY ENERGIES
Authors: Barber R. C. , Bishop R. L. , McLatchie W. , Rookhuyzen P. Van , Duckworth H. E.
Published: April 2011

Values are reported for the Zr92–Zr90, Zr94–Zr92, and Zr96–Zr94 mass differences. These are combined with existing data to compute neutron separation energies for Zr94 and Zr96, and the energies available for the Zr96–Nb96 and Nb94–Zr94 decays. It is pointed out that marked regularities exist amongst the neutron separation energies for zirconium and tin.
VIBRATIONAL RELAXATION IN DISSOCIATING DIATOMIC GASES
Authors: McChesney M.
Published: April 2011

This article questions the available theoretical analyses relating to the vibrational excitation of a dissociating gas which assume that the gas dissociates from vibrational level populations given by the Maxwell–Boltzmann distribution law. The two theories of thermal dissociation are briefly outlined and it is shown that either theory gives non-equilibrium-level populations. Furthermore, the use of a simple relaxation equation to describe the vibrational excitation of anharmonic oscillators in high vibrational levels is questioned.
CALCULATIONS OF REDUCED PROBABILITY FOR E2 TRANSITIONS IN BETA AND GAMMA BANDS
Authors: Preston M. A. , Kiang D.
Published: April 2011

For convenience in analysis of experiments on nuclear energy levels, we list specific formulas for the reduced probabilities of E2 transitions between rotational levels built upon β- and γ-vibrational bands for axially symmetric even–even nuclei.
DEVICE FOR MEASURING THE CHANGE IN REMANENT MAGNETIC MOMENT OF ROCKS WITH TEMPERATURE
Authors: Krause B. R.
Published: April 2011

An instrument has been designed and built to permit the measurement of the magnitude and direction of the magnetic dipole moment in a one-inch cubical rock specimen while the specimen is in a furnace. The measurement is obtained by giving the specimen a linear vibration at 40 c.p.s. and surrounding the furnace with a specially designed array of coils. Each of the three mutually perpendicular components of the dipole moment induces a voltage in the coils. By rearranging the interconnection of the coils, outputs proportional to any component may be obtained. This apparatus has a theoretical sensitivity to magnetization of about 4 × 10−5 e.m.u. (per cc). The actual sensitivity approached this but was limited by external electrical interference.
THE 6.48-MEV LEVEL OF C11
Authors: Braben D. W. , Riley P. J. , Neilson G. C.
Published: April 2011

The 6.48-Mev level of C11 has been studied by means of the B10(d,nγ)C11 reaction using time-of-flight techniques. The results show that the ratio of the ground-state transition to the cascade via the second excited state of C11 is 8 ± 1:1. Comparison is made with the predictions of the intermediate-coupling model.
THE APPLICATION OF A NEUTRON IDENTIFICATION CIRCUIT TO THE STUDY OF FAST-NEUTRON INTERACTIONS IN STILBENE
Authors: Johnson F. A.
Published: April 2011

A neutron identification circuit is described which has a threshold corresponding to a neutron energy of about 350 kev (50–60 kev equivalent electron energy). The photomultiplier is operated under conditions of space-charge saturation. Selection of pulses due to recoil protons or heavier particles is accomplished by allowing the initial negative-going spike of the space-charge-limited pulse from the last dynode to activate a trigger circuit, the output of which is used to gate the subsequent positive portion of the dynode pulse for presentation to a simple diode discriminator. Separation of pulses due to recoil protons and to α particles is also possible to some extent.The circuit is applied to an investigation of fast-neutron interactions in stilbene. For the case of 14.85-Mev neutrons it is shown that the majority of pulses of low light-output are due to α particles produced by neutron interactions with the carbon and that structure is apparent in this α-particle spectrum. α-Particle groups due to the C12(n, α)Be9 reaction and to the breakup of C12 from its excited states at 7.656 Mev and 9.63 or 10.1 Mev are identified.
RANGE OF Xe133 AND Ar41 IONS OF KILOELECTRON VOLT ENERGIES IN ALUMINUM
Authors: Davies J. A. , Brown F. , McCargo M.
Published: April 2011

Detailed studies of the range and range distribution of Xe133 and Ar41 ions in aluminum have been made over a wide energy region: 0.5–240 kev for Xe; 0.7 kev to 2.25 Mev for Ar. The results agree well with the previous alkali metal ion measurements. The experimental distribution curves consist of an asymmetric peak followed by a point of inflection and an exponential tail. The change in peak shape with increasing energy agrees at least qualitatively with the expected transition from nuclear to electronic stopping. The theoretical range–energy curve of Lindhard and Scharff fits the experimental data quite well over most of the energy region studied, but significant deviations occur at the lower energies.
A POSSIBLE ORIGIN OF THE HAWAIIAN ISLANDS
Authors: Wilson J. Tuzo
Published: April 2011

It is noted that different physicists and geologists have in recent years espoused not less than four groups of theories of the physical behavior of the Earth's interior. Recent observations of submarine geology, heat, and rock magnetism have tended to support some form of continental drift rather than the older concept of a rigid earth.The Hawaiian Islands are one of seven, parallel, linear chains of islands and seamounts in the Pacific Ocean of Tertiary to Recent age. Their nature had previously been explained in terms of a series of volcanoes along parallel faults. Horizontal shear motion along these faults was supposed to be extending them southeasterly.The inadequacies of this explanation are pointed out. If there are convection currents in the Pacific region and if the upper parts of these cells move faster than the central parts, sources of lava within the slower moving cores could give rise to linear chains of progressively older volcanic piles such as the Hawaiian Islands. This view is shown to be compatible with seismic observations and age determinations.