bluuebunny/crossref_metadata_2025 huggingface dataset:
Taphonomy of a mass-death layer of fishes in the Paleocene Paskapoo Formation at Joffre Bridge, Alberta Canada
Authors: Wilson Mark V. H.
Published: October 2017

A layer of silty mudstone only a few centimetres thick, in the lower part of the mainly fluvial Paskapoo Formation, contains thousands of complete skeletons of fossil fish and is Tiffanian (Late Paleocene, Ti3) in age. The diversity represented in the layer is low, with thousands of specimens of a species in the trout-perch family (Percopsidae), tens of specimens of a species in the smelt family (Osmeridae), and just two specimens of a species of osteoglossomorph in the family Osteoglossidae recovered to date. Although the fishes occur without other kinds of fossils in the "Fish Layer," other layers in the same outcrop have yielded abundant remains of plants, insects, mollusks, and mammals. Taphonomic features of the Fish Layer are used to test the hypothesis that it represents a mass-death event and to evaluate mechanisms of formation. There is little disarticulation and no sign of scavenging, fish occur in distinct size classes, individuals of the smelt species demonstrate breeding tubercles, fish tend to be clumped together on a scale of a few metres or less, and fish tend to lie with their heads facing one or perhaps two preferred directions. These findings suggest that the deposit represents a mass-death event, probably occurring during spring or early summer high water while the fish were attempting to spawn in shallow water, and that the layer itself was deposited under the influence of gentle currents and wave action. Such conditions could have occurred during or following a flood that trapped the fish in an overbank, backswamp, or abandoned-channel pond or shallow lake, as has recently been suggested on sedimentological and stratigraphic evidence. Rapid burial is probably the reason for the lack of scavenging and disarticulation. This deposit shows that well-preserved fish skeletons can be found in large numbers in fluvial formations, representing paleoenvironments and time intervals for which our knowledge of fish diversity has been poor in the past.
Geology and U-Pb geochronology of Archean basement and Proterozoic cover in the Priest River complex, northwestern United States, and their implications for Cordilleran structure and Precambrian continent reconstructions
Authors: Doughty P T , Price R A , Parrish R R
Published: October 2017

Precambrian basement rocks exposed within tectonic windows in the North American Cordillera help to define the Precambrian crustal structure of western North America and possible reconstructions of the Late Proterozoic supercontinent Rodinia. New geologic mapping and U-Pb dating in the infrastructure of the Priest River metamorphic complex, northern Idaho, documents the first Archean basement (2651 ± 20 Ma) north of the Snake River Plain in the North American Cordillera. The Archean rocks are exposed in the core of an antiform and mantled by a metaquartzite that may represent the nonconformity between basement and the overlying Hauser Lake gneiss, which is correlated with the Prichard Formation of the Belt Supergroup. A structurally higher sheet of augen gneiss interleaved with the Hauser Lake gneiss yields a U-Pb zircon crystallization age somewhat greater than 1577 Ma. The slivers of augen gneiss were tectonically interleaved with the surrounding Hauser Lake gneiss near the base of the Spokane dome mylonite zone, which arches across this part of the Priest River complex. We conclude that the Spokane dome mylonite zone lies above the Archean basement-cover contact and that it was, in part, equivalent to the basal décollement of the Rocky Mountain fold and thrust belt. New U-Pb dates on metamorphic monazite and xenotime reveal peak metamorphism at ca. 72 Ma, compatible with movement along the Spokane dome mylonite zone at that time. The Archean basement could be interpreted as the western extension of the Hearne province, or a new Archean basement terrane separated from the Hearne province by an Early Proterozoic suture. The unique assemblage of 2.65 Ga basement, ~1.58 Ga felsic intrusive rocks, and the Middle Proterozoic Belt Supergroup can be used as a piercing point for the identification of the conjugate margin to Laurentia. Our new dating supports previous correlations of Australia's Gawler craton (2.55-2.65 Ga) and its 1590 Ma plutons with the Priest River complex basement gneisses. The Priest River complex basement may be a piece of eastern Australia stranded during rifting of the supercontinent Rodina in the Late Proterozoic.
Mysterious iron-nickel-zinc arctic spherules
Authors: Darby Dennis A
Published: October 2017

An investigation into the sources of ice-rafted detritus in the central Arctic Ocean using microprobe analyses of detrital Fe oxide minerals discovered unique magnetic spherules in 20 of 144 potential source sample sites from the shelves and coastal areas around this ocean. The spherules occur only in samples from the Queen Elizabeth Islands, Canada. These grains are characterized by a 45-60 µm diameter, pitting throughout, and are occasionally found as multiple joint spherules. They have the optical properties of magnetite and, most remarkably, contain both ZnO and NiO in subequal amounts of up to 25%. The Ni suggests either an anthropogenic or meteoritic source. These spherules were probably ice-rafted into the central Arctic Ocean, where they are found in sediments of Holocene age and back to at least 780 ka, eliminating an anthropogenic source. Because Zn is too volatile to survive entry of a meteor through the earth's atmosphere, these spherules were probably formed during impact of an Fe-Ni meteor in an area of abundant Zn, perhaps the Zn rich Paleozoic carbonates of the Queen Elizabeth Islands. Examination of the ejecta and sediments filling the 22 Ma Haughton Astrobleme impact site on Devon Island, a carbonate terrain, revealed few magnetite spherules. None of these were pitted or contained Ni, but a few percent of ZnO were found in three spherules. Thus, the origin of these magnetite spherules remains unknown. The unique appearance and geochemistry of these spherules are useful in tracing Arctic Ocean ice-rafted detritus to its source.
Variability in Paper Electrophoretic Patterns of the Serum of Landlocked Sea Lamprey, Petromyzon marinus Linnaeus
Authors: Thomas M. L. H. , McCrimmon H. R.
Published: October 2017

One hundred and fifty-eight samples of sea lamprey (Petromyzon marinus L.) blood were analyzed using paper electrophoresis at pH 8.6. The specimens were of two phases in lamprey life history, the parasitic phase and pre-spawning phase. Variations in serum protein concentration, positions and sizes of the fractions were associated with the state of life history, sex and disease. Most of the variation between phases of life history was in the dominant fraction, an albumin. There was a decrease in total stainable protein while specimens were starved in captivity. Disease caused several changes in the pattern, the most striking of which was an increase in the size of fraction 6, probably α-globulin.
Structural Homogeneity in Unsaturated Fatty Acids of Marine Lipids. A Review
Authors: Ackman R. G.
Published: October 2017

Consideration of recent analytical data supports the conclusion that the longer-chain polyunsaturated fatty acids of marine origin are all structurally homogeneous in that the double bonds are cis, the double bonds methylene interrupted, and that, with the exception of the C16chain length, the ultimate double bond will normally be three, six or nine carbon atoms removed from the terminal methyl group.
Observations on the Milky Condition in Some Pacific Coast Fishes
Authors: Patashnik Max , Groninger Jr. Herman S.
Published: October 2017

The milky condition in some Pacific coast fishes was studied because of its effect on quality and salability of fishery products. Affected milky areas displayed relatively high proteolytic activity, whereas adjacent unlysed areas showed little or no activity. The proximate composition for the whole fish remained within normal limits. The myxosporidian parasites causing the condition were readily identified microscopically by their characteristic spores.
Net Avoidance Behavior of Carp and Other Species of Fish
Authors: Hunter John R. , Wisby Warren J.
Published: October 2017

The net avoidance behavior of carp, Cyprinis carpio Linnaeus, was studied in the laboratory. The effect of the size of the tank, temperature, light, social behavior, and air bubbles was evaluated and the behavior of carp was compared to that of nine other species of freshwater fishes.Carp tended to escape a net in the same relative position in tanks of different lengths. Fish in cold water used a bottom escape route while those in warm water used an escape route located at the top of the net. Groups were more successful in avoiding a net than were isolates. In warm water there was an immediate difference between the performance of groups and isolated fish; in cold water differences appeared after training. Blind carp and carp tested in turbid water were less successful in avoiding a net than were fish with unimpaired vision. Groups of carp avoided portions of an escape route which were occluded by air bubbles.
An Unusually Late-Spawning British Columbia Chum Salmon
Authors: Wickett W. Percy
Published: October 2017

not available
Feeding by Alewives (Alosa pseudoharengus) on Larval Lake Whitefish (Coregonus clupeaformis) in the Laboratory
Authors: Hoagman Walter J.
Published: October 2017

Adult alewives (Alosa pseudoharengus) from Lake Michigan readily ate larval lake white-fish (Coregonus clupeaformis) of 16.3 mm (standard deviation 1.4 mm) average length in the laboratory. They ignored the larvae when the latter had grown to 19.5 mm (SD = 1.6 mm) and 24.9 mm (SD = 3.2 mm) average length.
Length polymorphism scanning is an efficient approach for revealing chloroplast DNA variation
Authors: Horning Matthew E , Cronn Richard C
Published: October 2017

Phylogeographic and population genetic screens of chloroplast DNA (cpDNA) provide insights into seed-based gene flow in angiosperms, yet studies are frequently hampered by the low mutation rate of this genome. Detection methods for intraspecific variation can be either direct (DNA sequencing) or indirect (PCR–RFLP), although no single method incorporates the best features of both approaches. We show that screening universal chloroplast amp li cons for length polymorphism provides an accurate and efficient method for identifying cpDNA variation. By sequencing 4500 bp of cpDNA from 17 accessions of Purshia tridentata (bitterbrush), we detected 9 haplotypes, 8 of which were identifiable by unique multilocus length combinations resolvable by automated fragment analysis. In silico estimates of PCR–RFLP for these loci show that 5 haplotypes would be resolved by agarose electrophoresis. A survey of 4 intraspecific data sets from diverse angiosperms revealed that length variation in cpDNA amplicons is nearly ubiquitous, and 61 of 67 haplotypes identified by direct sequencing could be identified by screening length variation. Combined with automated fluorescent detection, length polymorphism screening of universal cpDNA regions offers a simple screen for intraspecific variation that can be used across angiosperms with minimal optimization, providing detection limits that rival direct sequencing at a fraction of the cost.Key words: cpDNA, intraspecific polymorphism, population genetics, phylogeography, indels.
Drinking water quality and treatment: the use of artificial neural networks
Authors: Baxter C W , Zhang Q , Stanley S J , Shariff R , Tupas R -RT , Stark H L
Published: October 2017

To improve drinking water quality while reducing operating costs, many drinking water utilities are investing in advanced process control and automation technologies. The use of artificial intelligence technologies, specifically artificial neural networks, is increasing in the drinking water treatment industry as they allow for the development of robust nonlinear models of complex unit processes. This paper highlights the utility of artificial neural networks in water quality modelling as well as drinking water treatment process modelling and control through the presentation of several case studies at two large-scale water treatment plants in Edmonton, Alberta.Key words: artificial neural networks, water treatment process control, water treatment modelling.
On quantum scattering by δ'(x)} and quasi δ'(x) distributions
Authors: Dubey R K , Menon V J , Pandey M K , Tripathi D N
Published: October 2017

The zero-range interaction U(x) occurring in the one-dimensional, time-independent Schrödinger equation is regarded as a smoothed distribution characterized by a tiny length scale b such that the origin becomes an ordinary point. A neighbourhood around the origin is scanned by defining inner demarcation points a±≡ ±b/N and outer demarcation points b±≡ ±Nb with N >> 1. Then a sequence of simple Lemmas permits (i) construction of a systematic procedure for simultaneously solving the scattering wave function ψ(0) at the origin, its derivative ψ'(0) there, the transmission amplitude B, as well as the reflection amplitude D; and (ii) unambiguous application to scattering by the previously known δ'(x) and newly proposed quasi δ'(x) potentials in the Cauchy representation of various distributions.PACS No.: 03.65.Nk
Rotation–Vibration Coupling in Diatomic Molecules and the Factorization Method. II. Closed Form Formulas for the Morse–Pekeris Intensities
Authors: Badawi M. , Bessis N. , Bessis G. , Hadinger G.
Published: October 2017

It is shown that, by applying an "accelerated" ladder operatorial formalism or an equivalent matrix procedure, one can obtain, easily, for the case of a Morse–Pekeris potential, a closed form expression of the rotation–vibration nuclear dipole moment matrix elements. This explicit expression, which is valid for any degree k of the dipole moment Taylor's expansion, allows the determination of the rotation–vibration intensities for any ΩνJ → Ω′ν′J′ transition.
Spectre d'émission de la molécule PO : Etude des états 2Σ+ situés dans le domaine énergétique 50 000–58 000 cm−1 des molécules P16O et P18O
Authors: Ngo T. A. , Paz M. Da , Coquart B. , Couet C.
Published: October 2017

The rotational analysis of bands of P16O and P18O molecules has been carried out by emission experiments. These bands, all perturbed, correspond to transitions from A2Σ+, F2Σ+, G2Σ+, H2Σ+ and I2Σ+ to B2Σ+, A2Σ+ and X2Π states in the respective regions 3850–5300, 6500–7000, and 1800–2000 Å.

The results of first- and second-order deperturbations for the observed interactions give the values of the constants of the F, G, H, and I states with a better accuracy than that obtained previously by Verma et al. Particularly, they infirm the hypothesis of a predissociation of some vibrational levels by the repulsive A′2Σ+ state and permit the assignment of a new quantum specification to the H2Σ+ state.

The electronic structure and the order in energy of the Rydberg states considered are then consistent to those which have been proposed by Ackermann et al.
Search for Voids in a Reactor Calandria Sample by Means of Positron Annihilation and Electron Microscopy
Authors: Kim S. M. , Buyers W. J. L. , Martel P. , Carpenter G. J. C.
Published: October 2017

We have measured the positron annihilation angular distribution in 1S Al subjected to neutron irradiation while part of the NRX reactor calandria, in annealed IS Al, and in heavily deformed 1S Al, which simulates the cold working of the calandria sample before irradiation. The FWHM in the calandria and deformed samples were found to be similar and 11% narrower than that in the annealed sample, indicating that the dominant defects in the calandria are dislocations rather than voids. Electron microscope examination of the above samples also indicated a high density of dislocations and no significant void population in the neutron irradiated calandria.
Absorption of OH in the 1200 Å Region
Authors: Douglas A. E.
Published: October 2017

A strong absorption band of OH has been observed near 1221 Å. From the analysis of high resolution spectra, it has been determined that the upper state is a 2Σ− Rydberg state and the constants of the OH and the corresponding OD state have been obtained. It is shown that the new absorption band will give interstellar absorption lines of OH at 1221.166, 1222.071, and 1222.524 Å. New constants have also been determined for the A2Σ+ and X2Π states of OD.
Deviations From Matthiessen's Rule in Nonmagnetic Copper-Based Alloys
Authors: Black J. E.
Published: October 2017

The deviations from Matthiessen's rule in copper-based alloys caused by anisotropy in the non-equilibrium part of the electron distribution function are calculated. The results, while in qualitative agreement with experiment, differ in several important quantitative details. Thus a simple theory, based only on the anisotropy, may be inadequate to explain the known deviations from Matthiessen's rule in copper-based alloys.
Many-Electron Correlations in the Photoionization of a Nitrogen Atom
Authors: Cherepkov N. A. , Chernysheva L. V. , Radojević V. , Pavlin I.
Published: October 2017

Photoionization cross sections for the outer shell of the nitrogen atom ground state are calculated in the single-particle Hartree–Fock approximation and, in order to take into account many-electron correlations, also in the Random Phase Approximation with Exchange (RPAE). To be able to apply the RPAE, its modification for the half-filled shell atom, such as nitrogen atom, is presented. Calculation of length and velocity forms of the cross section in both approximations are compared with the available experimental data, and a good agreement is obtained. It has been found that in the RPAE the influence of many-electron correlations in a nitrogen atom is not great, but it is very important since, in contrast to the Hartree–Fock approximation, it results in the validity of the sum rule and the coincidence of the length and velocity forms of the cross sections, in agreement with the requirement of the general theory. The angular distribution of photoelectrons is also calculated in the RPAE, which has not been measured so far.
Electron Density Behavior Near the Axis of a Turbulent Hypersonic Sphere Wake
Authors: Heckman D. , Sévigny L. , Emond A.
Published: October 2017

Langmuir probes have been used to obtain estimates of electron density close to the axis of the turbulent wakes of 6.82 cm (2.7 in.) diameter spheres flown at 4420 m/s(14 500 ft/s) in air atmospheres at 10 Torr. A brief résumé and discussion is given of the principal experimental results.
Magnons and Phonons in Cobalt Ferrite
Authors: Teh H. C. , Collins M. F. , Mook H. A.
Published: October 2017

Magnons and phonons have been observed in a single crystal of cobalt ferrite, CoFe2O1 at room temperature. Dispersion relations are plotted for the [001] and the [111] directions. The longitudinal acoustic phonon branch has been measured out to the zone boundary in both directions, while the transverse acoustic branch has been completely determined only in the [001] direction. The acoustic magnon branches are well defined at low energies, but they rapidly lose intensity and disappear at around 9 THz. We have not determined uniquely why this happens, but some possibilities are given. Optic branches have been observed at around 11.3 and 14.0 THz. Infrared data indicate that the first branch is probably of phonon character and the second of magnon character.
An Interferometric Method for Determining the Coexistence Curve and Diffusion Coefficient of a Binary Fluid
Authors: Balzarini David A.
Published: October 2017

An interferometric method is described for determining the coexistence curve of a binary fluid. A thin sample containing a binary fluid at a temperature below the critical temperature such that two phases coexist is heated to a temperature greater than Tc. As the two phases diffuse together, the concentration and refractive index attain sigmoid distributions. The Fraunhofer diffraction pattern produced by a collimated laser beam traversing the sample is analyzed to obtain the concentration difference as a function of temperature. The change of the Fraunhofer pattern with time yields information about the temperature and concentration dependence of the diffusion coefficient. Results for the binary fluid aniline–cyclohexane are presented.
Green–Kubo Formulae for a Plasma in an External Magnetic Field
Authors: Corkum P. B. , McLennan J. A.
Published: October 2017

The relation between linearized magnetohydrodynamics and the space and time dependent correlation functions of a plasma in an external magnetic field is derived. The method used is a perturbation technique based on the assumption that the correlation functions can be decomposed into a slow, hydrodynamic, and a rapid, microscopic, part. Using this method, the hydrodynamic modes are determined, and the description of magnetohydrodynamics found in this manner is assumed to be identical to regular magnetohydrodynamics. The resulting correspondence yields a set of correlation function expressions for the transport coefficients and magnetohydrodynamic modes.
Diffraction by a Laser Induced Thermal Phase Grating II
Authors: Enns R. H. , Rangnekar S. S.
Published: October 2017

The theory of the diffraction by a laser induced thermal phase grating is extended into the picosecond regime and applied to the experimental data of Scarlet. The agreement between theory and experiment is good.
The Forbidden Pure Rotational Spectrum of SiH4: the R Branch
Authors: Rosenberg Arieh , Ozier Irving
Published: October 2017

The R branch of the pure rotational spectrum of SiH4 in the ground vibronic state has been studied in the spectral region 60 to 134 cm−1 using a Michelson interferometer and a 10.6 m cell. Thirteen lines have been observed and identified as forbidden (J → J + 1) transitions for rotational levels from 10 to 22, with the absorption mechanism being provided by the centrifugal distortion dipole moment μD. The two strongest competing mechanisms are discussed and eliminated from consideration: transitions within the vibrational excited state ν4 and the difference band ν2 – ν4. In the data analysis, the frequency shift due to the fourth rank tensor distortion interaction is taken into account by an extension of the earlier work on GeH4 by Ozier and Rosenberg. It has been determined that the rotational constant B0 = (2.8574 ± 0.0027) cm−1 and the scalar distortion constant Ds = (3.48 ± 0.54) × 10−5 cm−1. From estimates of the line intensities, it has been found that [Formula: see text].
Rotational Structure in the (2,0) Band of the C2 Δ3/2–X2 Π1/2 Subsystem of SbO
Authors: Rai S. B. , Rai B. , Rai D. K.
Published: October 2017

The rotational structure in (2,0) band of C2Δ3/2–X2Π1/2 subsystem of SbO molecule has been photographed in the third order of a 35 ft concave grating spectrograph, and the rotational constants of the two combining states have been determined. It is found that the new rotational constants for the ground state are in agreement with those reported by Rai et al., but the constants for the excited state differ appreciably from those reported earlier by Rao and Rao. A small λ-type doubling (≈4.0 × 10−6 cm−1) is observed in the excited state. The isotopic lines due to 123SbO have also been observed.
Lifetime Effects in Coupled Channel Problems
Authors: Kamal A. N. , Kreuzer H. J.
Published: October 2017

Lifetime effects of unstable particles in coupled channel problems are studied in a simple field theoretical model and in some nonrelativistic 2-channel models. The instability of higher channel particles is taken into account via self-energy effects. Resonance and cusp modifications are studied numerically in great detail.
Electron–Phonon Scattering Times for Aluminum
Authors: Truant P. T. , Carbotte J. P.
Published: October 2017

The electron–phonon scattering times in pure aluminum vary with position on the Fermi surface. There are several sources of this anisotropy. Perhaps the most obvious, but not necessarily the most important, is the distortions of the Fermi surface from a sphere. Another results from the anisotropy in the electron–phonon interaction and in the phonon spectrum. We have calculated the effect on the electron–phonon scattering times of this latter source of anisotropy. We find large variations over the Fermi surface. As the temperature is increased the anisotropy reduces but it is still significant even above 100 K.
Plasmon Satellites in Auger Spectra
Authors: McMullen T. , Bergersen B.
Published: October 2017

A theory of Auger spectra in light metals, in which a nonequilibrium formalism is used to handle the aspects of the problem associated with energy loss of the fast electrons and decay of the excited core hole, is presented. The Auger electrons are assumed to reach the surface a time τ after the initial excitation. This time is determined by the decay characteristics of the initial core hole, the geometry, and the velocity of the Auger electrons. After τ, it is assumed that no interactions occur. Electron gas correlations are approximated by a bulk plasmon model. The initial excitation may be due to either X-ray or electron bombardment, although we concentrate on the former. Plasmon production by the primary ejected electrons and the suddenly created core hole is considered. The formalism is based on a perturbation expansion in the electron–plasmon interaction after extraction of the energy shifts, and this procedure is justified by comparison with a simple soluble model. It is applied to third-row (K; LL) Auger transitions. The plasmon gain satellite is compared to the main line, and the entire spectrum is computed in detail for the limiting case of a long lived core hole.
On the Lie Symmetry Groups for Classical Fields
Authors: Oliveira Colber G.
Published: October 2017

The symmetry Lie groups associated with isolated fields are derived from an analogy with the corresponding problem for particle dynamics. These symmetry groups may contain point to point transformations which depend on the values assumed by the field function at the point which is being transformed. Some examples are given, and some of the possible implications of the present method are discussed.
An Approximate Sum Rule for de Haas–van Alphen Frequencies of Free Electron-like Conductors
Authors: Wenger A.
Published: October 2017

The general relationship between sums and differences of de Haas–van Alphen frequencies and certain cross sectional areas of the Fermi surface in the extended zone scheme is derived. As shown in the case of AuPb2, this result may help to interpret de Haas–van Alphen data of free electron-like conductors.
The 44Ca(d,α)42K Reaction at 4.0 MeV
Authors: Lee S. T. , Long D. D.
Published: October 2017

The angular distributions from the 44Ca(d,α)42K reaction were measured at Ed = 4.0 MeV in a range of angles from 40° to 160°. Based on the observation of forward peaking of the angular distributions and diminished fluctuations at 4 MeV in the excitation function, an analysis was carried out utilizing the distorted wave Born approximation. For the five strongly excited levels below 1.3 MeV, satisfactory fits were obtained using optical model parameters from the literature. The results, which were consistent with the spin assignments from other experiments, revealed no gross inadequacies of a direct reaction analysis at this energy which are not present at higher energies. For three levels in42K, the range of spins was tentatively reduced. In the case of the 1.113 MeV level, no previous assignments had been made.
Lifetimes and Oscillator Strengths in Singlet Levels of Strontium
Authors: Kelly F. M. , Koh T. K. , Mathur M. S.
Published: October 2017

Coherence narrowing and collision broadening of the 5s5p1P1 level of strontium have been studied. The natural lifetime of this level has been determined to be 4.68 ± 0.10 ns. The oscillator strength of the 4607 Å transition is 1.94 ± 0.06, and the f values of the transitions from the 5s6p, 5s7p, and 5s8p1P1 levels to the ground level and the 5s4d1D2 metastable level have been reevaluated. The cross section for Sr–Sr collisions is found to be [Formula: see text].
Equilibre de phases dans une couche monomoléculaire de molécules semi-flexibles
Authors: Caillé Alain
Published: October 2017

We use a lattice model to calculate the free energy of mixing of semiflexible molecules and molecules of solvent forming a monomolecular layer. The different semiflexible chain configurations are represented using a given plan of occupation of the lattice points. The proposed solution considers only the repulsive forces and the steric hindrance due to the internal rigidity of the chains. The probability of occupation of a point of the lattice is calculated using an average over the entire lattice. We calculate the canonical partition function taking into account the energies of the different chain configurations of the semiflexible molecules. For typical values of the difference in energy between the gauche and the trans configurations, we conclude that the condensed phase has orientational ordering where the molecules are perpendicular to the subphase. We calculate the equilibrium of phases between a system of ordered chains and a system of disordered chains. The results of this calculation allow us to stress the importance of the repulsive forces.
Low Density Density Derivative of the Self-Correlation Function of a Hard Sphere Gas
Authors: Blair D. G. , Pope N. K.
Published: October 2017

For the classical gas of hard spheres, exact expressions are derived for [∂Is(r,t)/∂n]n = 0, [∂Is(q,t)/∂n]n = 0, and [∂Ss(q,ω)/∂n]n = 0, the density derivatives of the Van Hove self-correlation functions. The relationships between the direct derivation using the activity expansion, and the derivations based on the generalized kinetic equation and the linearized Boltzmann equation are discussed. Properties of these density derivatives and of the corresponding self-correlation functions, as given by the first two terms of the density expansion, are discussed in detail. The expressions are compared with the hard sphere results of Desai and Nelkin. of Sears and of Mazenko et al.; and also with the predictions of the single relaxation time model and the Langevin diffusion model.
Propagation of Nonlinear Electromagnetic Field Theories
Authors: Shamaly A. , Capri A. Z.
Published: October 2017

It is shown that the self-interaction term λ(AμAμ)2 added to the free Lagrangian for Maxwell's equations leads to acausal propagation. Furthermore, it is found that apart from the term λAμAμ which leads back to the Proca equation, all self-interaction terms leading to causal propagation must be nonpolynomial.
Positron Annihilation in Teflon and Polyethylene
Authors: Kerr Donald P.
Published: October 2017

Both the time spectra and the angular distributions of the annihilation gamma rays have been measured for positrons annihilating in Teflon and polyethylene in an attempt to clarify which annihilation mechanisms account for the various lifetimes in these materials.

Some authors have suggested that, in addition to the longest lifetime component, one of the shorter lived components also arises from the pickoff annihilation of orthopositronium. If this were the case, substantially more positronium would be formed than is indicated by the intensity of the longest lived component alone, and should be detectable through a measurement of the intensity of the low momentum portion of the momentum distribution obtained from the angular correlation data.

In the present work, four lifetimes are apparent in the time spectra although there is considerable uncertainty in resolving the two shortest components. The angular distribution data, in both cases, yielded a low momentum component whose intensity indicates that only the longest lifetime component arises from pickoff annihilation of orthopositronium.

The three shorter lifetime components are discussed.
An Investigation of Odd Parity States in 32S
Authors: Grawe H. , Cairns J. E. , Greene M. W. , Kuehner J. A.
Published: October 2017

States in 32S have been populated using the 31P(p,γ) reaction at the Ep = 895, 1438, and 1583 keV resonances. Angular distributions, a linear polarization measurement, and the results from the 32S(α,α′) reaction at 180° yielded the following spin and/or parity assignments for bound levels Jπ(6.62) = 4−, Jπ(6.76) = 3−, 4+, 5−, Jπ(6.85) = 3−, 4+, and Jπ(7.95) = 3, 4, 5−, and for resonance states J(10.26) = 4 and J(10.40) = 4. The γ decay of selected excited states has been studied and mixing ratios were obtained for the strongest branches. Doppler shift measurements yielded lifetimes of 810 (−250, +350) fs, > 300 fs and 110 (−40, +60) fs for the states at 6.62, 6.76, and 7.95 MeV respectively. The results are discussed and compared with shell model predictions.
Gaussian Beam Interaction with a Planar Dielectric Interface
Authors: Antar Yahia M. , Boerner Wolfgang M.
Published: October 2017

The problem of electromagnetic Gaussian beam scattering from a planar interface separating two lossless dielectric media is considered. Employing a modal plane wave expansion and the continuity of the fields across the boundary, the reflected and transmitted beams are obtained using the Fresnel approximation, and a Taylor series expansion of the reflection and transmission coefficients, for both polarizations. Particular emphasis is given to the beam shift of both the reflected and refracted beams, the change in width of the transmitted beam, and the behavior at polarizing incidence.
Collision Induced Microwave Absorption in CO2 and CO2–Ar, CO2–CH4 Mixtures in the 2.3 cm−1 Region
Authors: Dagg I. R. , Reesor G. E. , Urbaniak J. L.
Published: October 2017

Collision induced microwave absorption is reported in pure CO2, and CO2–Ar, CO2–CH4 mixtures in the 70 GHz (2.3 cm−1) region at a temperature of 22 °C, using a sensitive cavity technique previously described. The results in pure CO2 in the very low density region from 5 to 30 amagat accurately establish the dependence of the loss on the square and cube of the density, and the relaxation times are calculated. The experimental results agree well with previously reported lower frequency data at 0.3–0.8 cm−1 which establishes the linear dependence on frequency of the absorption up to 2.3 cm−1. There is also good agreement with an extrapolation of higher frequency infrared results of Ho et al. The relaxation times associated with the two and three body collisions are shown to be nearly equal at room temperatures with τ2 = 0.84 × 10−12 s and τ3 = 1.0 × 10−12 s. Higher order dependence on the density is observed for the CO2–Ar and CO2–CH4 mixtures. The results are compared with earlier low frequency measurements at 0.8 cm−1 and with the theory of Maryott and Kryder, taking account of correction terms in the dielectric virial coefficient according to Bose and Cole.
Some Forgotten Terms of the Dirac–Breit–Pauli Equation
Authors: Fraga S. , Karwowski J.
Published: October 2017

Two terms of the Dirac–Breit–Pauli equation, never considered before, are discussed. Their contribution to the total energy is of the same order of magnitude as the hyperfine structure interactions.
Velocity Distributions of Sphere Wakes
Authors: Lahaye C.
Published: October 2017

The present report is concerned with the wake velocity results measured in sphere wakes with the sequential spark technique. This technique has been employed to measure the radial distribution of velocity in the turbulent wakes of spheres flown at Mach numbers from 3.5 to 13 and at Reynolds numbers from 0.2 × 106 to 106 over a range of axial distance extending up to 3500 diam. For each selected combination of velocity, pressure, sphere diameter, and axial distance, a sufficient number of firings have been observed so as to permit the statistically meaningful determination of the mean profile of velocity. On 14 500 ft/s spheres, wake velocity mean characteristics were determined for ambient P∞D (pressure times sphere diameter) values of 20, 40, and 100 Torr-in. The results showed only a weak dependence of the wake velocity on P∞D. Measurements were also made at sphere velocities of 9000 and 4000 ft/s at a P∞D value of 100 Torr-in. The measurements revealed a strong influence of the Mach number on the wake velocity in the intermediate region of the wake. One of the important findings, observed under all the test conditions, is that the radial distribution of mean axial velocity in the turbulent wake is well approximated by a Gaussian curve.
Spectra of (H2)2, (D2)2, and H2–D2 Van der Waals Complexes
Authors: McKellar A. R. W. , Welsh H. L.
Published: October 2017

Spectra due to the Van der Waals complex (H2)2 have been obtained with greatly improved resolution, and analogous spectra of (D2)2 and H2–D2 have been observed. The experiments were conducted with an absorption path of 110 m in a multiple traversal cell at temperatures between 16 and 21 K. The spectra are manifested as fine structure accompanying the single and double H2 (or D2) transitions in the hydrogen (or deuterium) collision induced fundamental band. The observed structure for (H2)2 and H2–D2 can be unambiguously assigned to rotational transitions of the complex governed by the selection rule Δl = ± 1, ± 3, where l is the rotational quantum number of the complex. A detailed analysis must include anisotropic force effects, and is not given here. The spectrum of (D2)2 is complicated, not only by anisotropic force effects, but also by mutual perturbations between the rotational levels of the upper states of corresponding single and double D2 transitions; for this reason, the assignments suggested are somewhat uncertain. An interesting intensity alternation apparent in part of the (D2)2 spectrum is explained as a simple effect of nuclear spin statistics in the pseudodiatomic molecule (D2)2.
Nuclear g Factor of the 339 KeV Level of 59Ni
Authors: Wender S. A. , Cameron J. A.
Published: October 2017

The integral rotation of the angular distribution of 339 keV gamma rays from 59Ni has been measured following (α, n) reactions in a magnetized iron target. The g factor of the 5/2− first excited state of 59Ni is 0.14 ± 0.06.
Raman Studies of Molecular Reorientation in Liquid Sulfur Hexafluoride
Authors: Sunder S. , McClung R. E. D.
Published: October 2017

The contour of the v2 Raman band of SF6 liquid has been studied over the temperature range 226–315 K. Reorientational and angular momentum correlation times were obtained by comparing the Fourier transforms of the band contours with the reorientational correlation functions calculated using the J diffusion limit of the extended rotational diffusion model. A reanalysis of Hackleman and Hubbard's nuclear relaxation data for liquid SF6, using the correlation times obtained from the Raman studies, yields the value ± 6.2 × 104 s−1 for the asymmetry in the spin–rotation tensor [Formula: see text] for fluorine nuclei in SF6.
Rotational Analysis of the PH and PD A3Πi–X3Σ− Band Systems
Authors: Rostas J. , Cossart D. , Bastien J. R.
Published: October 2017

PH and PD radicals have been produced in a Schüler type discharge through PH3 and PD3. Besides the already known (0–0) bands of PH and PD, new bands, namely the (0–1) band of PH and the (1–0) and (1–1) bands of PD have been photographed in emission, under high resolution. Rotational analyses have been performed for these six bands and also for the (1–0) band of PH analyzed earlier by Legay in absorption. The 3Π and 3Σ states fine structure has been interpreted by a simple model, which includes spin–spin, and second-order spin–orbit interactions and also centrifugal distortion effects both on rotational and spin–orbit coupling parameters. The ν dependence of the different molecular parameters has been examined and interpreted where possible.
Poles of the S Matrix for a Complex Surface Delta Function Potential
Authors: Romo W. J.
Published: October 2017

The resonance properties of the potential V(r) = vδ(r–R) are investigated for both real and complex values of v (absorptive potentials). The poles of the s wave S matrix are given and the persistence of a resonance with increasing absorption is discussed.
The Spin of the 295 keV Level in 151Sm
Authors: Straume O. , Burke D. G. , Waddington J. C.
Published: October 2017

The angular distributions of gamma rays following Coulomb excitation of 151Sm by 50 and 75 MeV 35Cl ions were measured. The spin of the 295 keV level was uniquely determined to be I = 9/2.
Electron Correlation Functions in Liquids from Scattering Data
Authors: Egelstaff P. A. , March N. H. , McGill N. C.
Published: October 2017

Recent work on the theory of liquid metals has involved correlation functions for the ion–electron density and the electron–electron density. The experimental determination of these functions is discussed for a general homonuclear fluid. It is shown that the electronic correlation functions may be extracted, in principle, by combining X-ray, neutron, and electron scattering data, though the smallness of the differences between the normalized data makes this difficult to do at present.

After reviewing the published scattering data, we conclude that the most useful procedure is to compare scattered intensities at a significant reference point, namely the principal maximum of the liquid structure factor. X-ray and neutron data are presented for liquified rare gases, molecular liquids, and liquid metals, and their averages considered. Systematic differences are found between these groups, which prompt the conclusion that electrons in molecular liquids are delocalized by chemical bonding, but that the conduction electrons in a liquid metal have a higher degree of short range order than the nuclei. In this event an electron liquid, rather than an electron gas, exists in liquid metals.
Fundamental Absorption Band of HD
Authors: Bejar J. , Gush H. P.
Published: October 2017

The fundamental rotation–vibration band of HD has been resolved in the gas at 1 atm pressure. The line width appears to be totally due to the Doppler effect and equals 0.026 cm−1. The transition dipole moment has been calculated from the intensities of lines in the R branch: it is found to vary from 4 × 10−5 D for J = 0 to 7 × 10−5 for J = 4.
Ion Cyclotron Resonance Collision Frequencies of Alkali Ions in Rare Gases
Authors: Riggin M.
Published: October 2017

An ion cyclotron resonance (ICR) spectrometer was used to estimate collision frequencies of K+ and Na+ ions at near thermal velocities in helium and argon gases. The reduced zero field d.c. drift mobilities were found to be 11.4 and 40.7 cm2 PMU1/2/V s for 39K+ in Ar and He respectively and 11.6 and 42.8 cm2 PMU1/2/V s for Na+ in these gases. The effect of ion-neutral collisions on the energy distribution function for ions at resonance with an oscillating electric field is discussed and the average ionic energy as a function of neutral particle density obtained. In deriving the ICR line shape and ionic energy distribution function it is assumed that the mean time between momentum changing collisions is independent of the relative ion–neutral velocity.
Self-defocusing of an Acoustic Beam in Fluids
Authors: Mathur S. S. , Sagoo M. S.
Published: October 2017

The self-defocusing of an acoustic beam due to the phenomenon of acoustic streaming has been discussed. The defocusing effect increases the apparent coefficient of absorption and renders it to be intensity dependent. This is because the streaming is determined by the intensity of the ultrasonic beam.
Electron–Nuclear Double Resonance of 53Cr3+ in Aluminum Alums
Authors: Manoogian A. , Auger B.
Published: October 2017

Electron–nuclear double resonance (ENDOR) studies are reported for the isotope 53Cr3+ enriched to 96% in the aluminum alums RbAl(SO4)2∙12H2O and CsAl(SO4)2∙12H2O. The measurements were made at 4.2 K and X-band microwave frequencies (~9.4 GHz). The values of the spin Hamiltonian hyperfine parameters A, B, and Q′ are found to be quite similar to those obtained previously in the corresponding gallium alums even though the zero field splitting parameter D is significantly different. A plot of A − B vs. Q′ indicates that the amount of distortion existing at a chromium site can be related to the type of monovalent ion present, i.e. Rb or Cs. It is possible to draw straight line curves relating the parameters Q′ vs. D, A − B vs. D, and Vzz vs. D which account quite well for all the ENDOR data obtained so far in the alums and GAISH and which could be generally true for chromium magnetic complexes in crystals with D values not too close to zero.
Beam-Foil Mean Life Measurements of Levels in N I–N V
Authors: Kernahan J. A. , Livingston A. E. , Pinnington E. H.
Published: October 2017

Using the beam-foil technique, we have measured radiative mean lives for 41 levels in N I–N V within the wavelength range 374 to 2064 Å. In some cases we deduce experimental absorption oscillator strengths for comparison with recent theoretical calculations of Nicolaides, who used the 'Non-closed shell many electron theory' of Öksüz and Sinanoğlu. The agreement for lines of higher stages of ionization is very good.
Disorientation of Na(32P1/2) Atoms, Induced in Collisions with Noble Gases
Authors: Niewitecka B. , Skaliński T. , Krause L.
Published: October 2017

The cross sections for disorientation of 32P1/2 sodium atoms, induced in collisions with noble gas atoms, have been determined by following the depolarization of Na–D1 resonance fluorescence in relation to noble gas pressure. Sodium vapor at low density, mixed with a noble gas in a fluorescence cell, was irradiated with circularly polarized D1 resonance radiation and the resulting D1 resonance fluorescence, observed in an approximately backward direction, was analyzed with respect to circular polarization. The variation of the degree of polarization with gas pressure was interpreted on the basis of a 'J randomization' model for the collisions, and yielded the following disorientation cross sections which are appropriately corrected for effects due to nuclear spin. Na–He: 28.1 ± 4.0 Å2; Na–Ne: 27.8 ± 4.0 Å2; Na–Ar: 57.0 ± 8.0 Å2; Na–Kr: 78.0 ± 10 Å2; Na–Xe: 87.0 ± 13 Å2.
Lorentz–Lorenz Coefficient of Ethane
Authors: Burton M. , Balzarini D.
Published: October 2017

The index of refraction of ethane at 6328 Å has been measured in the density range 0.02 to 0.36 g/cm3(1 to 200 amagats). The coefficient in the Lorentz–Lorenz expression [Formula: see text] is constant to within 0.5% for the temperature and density range studied. The coefficient [Formula: see text] increases with density reaching a maximum near the critical density and decreases with density for densities larger than the critical density. The critical density has been measured in the same experiment and is 0.2062 ± 0.0003 g/cm3.
Some Old and New Expansions in the Perturbation Theory of Fluids
Authors: Smith William R.
Published: October 2017

A general functional Taylor expansion of the Helmholtz free energy and radial distribution function is derived for fluids and fluid mixtures. This gives rise to some known results for particular choices of expansion functional. The results are presented in a form convenient for numerical computation, and some calculations of g(r) for the fluid with potential u(r) = 4ε(σ/r)12 are presented. It is suggested that the present formalism may be useful for molecules with nonspherical pair potentials, and some new results are obtained for mixtures of such molecules.
Electron Resonances Associated with the Lyman System of H2 and D2
Authors: McGowan J. Wm. , Williams J. F. , Meckbach W.
Published: October 2017

The high resolution electron impact excitation of the H2 and D2 Lyman bands has been investigated. Particular attention has been paid to two series of (H2−2Σu+) resonances which decay into the B1Σu+(ν′) states.