bluuebunny/crossref_metadata_2025 huggingface dataset:
The Propagation of Compressional Alfven Waves in Nonuniform Plasmas
Authors: Morrow R , Brennan MH
Published: June 2011

A theoretical treatment is presented for the propagation of Alfven waves in a plasma. It includes the effects of resistivity, ion-neutral collisions, the ion cyclotron frequency and radial nonuniformities in ion density, neutral particle density and temperature. The theory is applied to plasmas with conducting and nonconducting walls and the results are compared with those of experiments conducted in the afterglow of a shock-produced plasma. Nonuniformity in the ion density is found to have a marked effect on the dispersion relation and wave field profiles, while non uniformities in the total particle density and temperature are less important. Excellent agreement is obtained between theory and experiment and this allows unambiguous and accurate determinations to be made of the average total particle density, which is found to be - 50 % of the initial filling density, and of the cross section for momentum transfer between protons and hydrogen atoms.
Variations of Spread-F Occurrence Rates at Near-equatorial Stations in the Australasian Zone
Authors: Cole DG , McNamara LF
Published: June 2011

The occurrence rates of spreadF for selected years between 1964 and 1972 are presented for three Australian stations lying between 10� and 25� magnetic latitude. Spreading is mainly of the rangespreading type. Two types of spread F are observed: one occurs during the solstices and correlates negatively with sunspot number; the other occurs during the equinoxes and correlates positively with sunspot number and negatively with magnetic activity. The relative importance of the two types is found to vary with latitude.
Probability Distributions for the Heights of Maxima and Minima in Fluctuating Nuclear Cross Sections
Authors: Branford D , Newton JO
Published: June 2011

Probability distributions for the heights of maxima and minima in fluctuating nuclear cross sections have been obtained from synthetic excitation functions. It is shown how these distributions can be used to determine the extent to which experimentally ob
Effect of Excited-state Decays on the Measured Angular Distribution of the 12C(g, p)11B Reaction
Authors: M Dixon Judith , Thompson MN
Published: June 2011

The angular distribution of photoprotons from i2e as measured directly and as deduced from the inverse reaction are compared. A discrepancy is revealed; it is resolved by proposing a small cross section for proton decay to excited states of 11 B. The size
Ising Model on a Triangular Lattice with Three-spin Interactions. I. The Eigenvalue Equation
Authors: Baxter RJ , Wu FY
Published: June 2011

It is shown that the Ising model with three-spin interactions on a triangular lattice is equivalent to a site-colouring problem on a hexagonal lattice. The transfer matrix method is then used to solve the colouring problem. The colouring of two neighbouri
Ising Model on a Triangular Lattice with Three-spin Interactions. I. Free Energy and Correlation Length
Authors: Baxter RJ
Published: June 2011

Following the demonstration in Part I that the Ising mogel with three-spin interactions on a triangular lattice is equivalent to a colouring problem on a hexagonal lattice, and that a generalized Bethe ansatz can be used to obtain equations for the eigenv
On the Dynamics of Equatorial Spread F
Authors: Beer Tom
Published: June 2011

A theory is proposed to explain the occurrence of spread F in the equatorial ionosphere. It is envisaged as a multistage process involving: movement of ionization drift with atmospheric gravity waves that results in spatial resonance, consequent enhanceme
A Determination of the Daytime Thermospheric Wind Profile by Observing a Lithium Trail with a Field-of-view Scanner
Authors: Hind AD , Lloyd KH
Published: June 2011

A description is given of the design of an instrument which has been built to detect the lithium 671 nm line against the daytime sky continuum. The instrument covers the field of view by means of a servocontrolled scanning mirror and detects the lithium l
Generation of Solutions of the Brans?Dicke Equations
Authors: Sneddon GE , McIntosh CBG
Published: June 2011

A method given by Geroch (1971) for generating new vacuum solutions from given solutions of Einstein's field equations is extended to the generation of vacuum Brans-Dicke solutions from both vacuum Einstein and vacuum Brans-Dicke solutions. Two theorems b
Lattice Vibrations in Vanadium
Authors: Pal Satya
Published: June 2011

The phonon dispersion curves, frequency spectrum and specific heat of vanadium have been calculated on the basis of the lattice dynamical model of Sharma and Joshi (1963). The frequency distribution has been derived according to Blackman's (1937, 1955) root-sampling technique by the numerical sampling of 192000 frequencies corresponding to 64000 points considered in the first Brillouin zone. This computed frequency distribution has then been used to calculate the lattice specific heat of vanadium. The resulting values of the specific heat have been compared with experimental measurements in terms of the Debye characteristic temperatures.
Convection in the Lower Atmosphere
Authors: Manton MJ
Published: June 2011

From the observations of Warner and Telford (1963, 1967), it would appear that fair-weather daytime conditions can produce a field of isotropically packed convection cells in the lower atmosphere. It is argued here that turbulence plays an insignificant role in the mechanics of one such cell, whose horizontal extent is small compared with its height. Thus a simple model of a convection cell is developed, and the predictions of this model are apparently consistent with the observations in the atmosphere.
Supersonic Neutral Winds in an Outer Atmosphere. I. Isothermal Conditions
Authors: Gilbert NE , Cole KD
Published: June 2011

The concept of steady nozzle flow along a narrow tube is applied to the motion of neutral gas constituents in a locally heated isothermal region of the outer atmosphere of a planet or star. The artificial nozzle throat at which the flow becomes supersonic is achieved by using one oftwo streamline functions within a vertical plane suggested by the possible shapes of convettion cells.
A Cosmological Model of Class One in Lyra's Manifold
Authors: Bhamra KS
Published: June 2011

A study is presented of a spherically symmetric class-one cosmological model based on Lyra's geometry. The static universe is shown to be physically unrealistic. The nonstatic model parallels Lemaitre's in the Riemannian case but the law of mass-energy onservation does not hold.
Synthesis Observations of Southern Radio Sources at 1410 MHz with the Parkes Interferometer. II. Polarization and Brightness Distributions Across Seven Sources
Authors: Schwarz UJ , Whiteoak JB , Cole DJ
Published: June 2011

The Parkes two-element interferometer, which provides a maximum resolution of ~ l' arc at a frequency of 1410 MHz, has been used to obtain the distributions of polarization and brightness across seven extended sources. The results seem to be consistent with a previous interpretation in which the magnetic fields of evolved sources are orthogonal to the direction of elongation but those of relatively young sources are parallel to this direction.
Positions and 1665 MHz Line Profiles for 10 Northern OH Emission Sources
Authors: Caswell JL , Robinson BJ
Published: June 2011

Positions with r.m.s. errors of about 20" arc have been determined for the stronger OH emission sources discovered in two northern searches. Line profiles at 1665 MHz with 1 kHz resolution are presented for both senses of circular polarization.
A Dual Absorptive Model for Backward Hadron Scattering
Authors: Rafique M , Saleem M , Bhatti Sanaullah
Published: June 2011

It is shown that a dual absorptive model can explain the dip structure of backward differential cross sections of hadronic processes. The polarizations in those backward processes in which the dominant contribution comes from non-flip amplitude are also found to be qualitatively consistent with experiment.
Many-atom Correlations and the Theory of Disordered Alloys
Authors: Towers GR
Published: June 2011

Some recent theories of disordered alloys are discussed with particular emphasis on their application to short-range ordered alloys. Comparisons are made in the case when only two-atom correlations are present. The probability variation method of Clapp (1969, 1971) is applied to allow inclusion of n-atom correlations which are dependent on the experimentally observable two-atom correlations. It is suggested that the cell method of Tsukada (1969) may be extended in the same manner.
An Aperture Synthesis Survey of the Galactic Plane
Authors: Jones BB , Finlay EA
Published: June 2011

The results of a survey already published have been used to construct contour maps and ruled surface diagrams of the brightness temperature at 29�9 MHz near the galactic plane between I = 225� and 30�. The angular resolution was 0�� 8 at the zenith, and the range of zenith angles involved was � 30�. Restoration of the background was achieved with the aid of a low resolution filled-aperture survey carried out by others. The brightness temperature scale was calibrated absolutely. The optical depth of the Galaxy in directions within 40� of latitude from the centre has been estimated by a method which relies only on the shapes of brightness temperature profiles and not on absolute temperature calibrations. If an electron temperature is assumed, r.m.s. electron densities can be deduced. The average value of the disc emissivity at 29�9 MHz and the value of its spectral index have been calculated from brightness temperature profiles observed at a number of different frequencies, calibrations being required for these purposes. About 29 discrete absorption regions have been observed and identified with optically observed HII regions, and the fact that these are all nearer than 4 kpc permits a choice between kinematic distances in two cases. The Carina nebula and RCW 108 lend themselves to the measurement of local emissivities, and values of these together with their implications have already been published. A number of previously unlisted nonthermal sources have been observed, many of which are objects of low surface brightness and probably are supernova remnants.
A Catalogue of Small-diameter Radio Sources Close to the Galactic Plane
Authors: Clark DH , Crawford DF
Published: June 2011

A catalogue of 'smaIl-diameter' galactic radio sources observed at a frequency of 408 MHz with the Molonglo radiotelescope is presented. The catalogue covers an area of 0�40 sr enclosed in the range [II = 190�-360�-50�, 1 bIll..;; 3�. The sources listed are those which show no significant broadening of the ~ 3' arc aerial beam. Small-diameter features bounded or confused by extended regions of emission are not included. A total of 513 sources are listed above a flux density of O' 6 Jy. While most of these are expected to be extragalactic, the list includes some known pulsars and small-diameter HII regions. The catalogue should form a useful search list for the identification of other such galactic objects.
Unitarity and Regge Branch Points
Authors: Joshi GC , Pagnamenta Antonio
Published: June 2011

We show how t-channel unitarity imposes constraints on the discontinuity associated with the leading Regge branch point. If the discontinuity across the leading Regge cut does not vanish at the end point it leads to the 'Gribov paradox'.
Multiple Scattering Effects in a Three-particle System
Authors: Cahill RT , Poole MS
Published: June 2011

We show that the phenomenological target wavefunction cutoff prescription arises naturally in the fixed scatterer approximation to particle scattering from a two-particle bound state. The wavefunction modification is found to describe the effects of higher order multiple scattering.
Gamma Ray Transitions following keV Neutron Capture in 2s-1d Shell Nuclei
Authors: Kenny MJ , Martin PW , Carlson LE , Biggerstaff JA
Published: June 2011

A Ge(Li) detector has been used to observe y-ray transitions after the capture of keV neutrons in natural samples of F, AI, Si, Sand Ar. Transitions to positive and negative parity states show that there are strong p-wave resonances as well as s-wave resonances in this mass region. The even-Z nuclei decay more by El transitions than by Ml. Odd-Z nuclei decay by strong Ml transitions.
Twenty-vertex Model on a Triangular Lattice
Authors: Kelland SB
Published: June 2011

An ice-type vertex model is formulated on a triangular lattice and solved exactly for restricted values of the vertex activities. It is found to undergo an infinite-order phase transition into an ordered antiferroelectric state and a first-order phase transition into a 'frozen' ferroelectric state.
A Radiating Charged Particle in an Expanding Universe
Authors: Patel LK , Shukla HC
Published: June 2011

The field of a radiating charged particle embedded in an expanding universe is discussed and approximate solutions of the field equations are obtained.
Australian Journal of Physics Astrophysical Supplement
Authors: Sutton JM , Davies IM , Little AG , Murdoch HS
Published: June 2011

bstract. The MC2 and MC3 catalogues of radio sources observed at a frequency of 408 MHz with the Molonglo telescope are presented. The catalogues include 609 and 657 sources in narrow strips of sky of areas O� 13 and O� 15 sr at declinations near + 11 0 and + 160 respectively. The catalogues are essentially complete above O' 40 f.u., corresponding to a source number density of ~ 3500 SCi, but include some sources as weak as O' 20 f.u. Typical errors in position are 6# at 2�0 f.u. and 16H at 0�40 f.u.
The Wick Rotation
Authors: O'Brien DM
Published: June 2011

A justification is presented for the use of the Wick rotation in the construction of solutions to Wick's equation. This is done by demonstrating the equivalence of the solutions found by Wick (1954) and by Green (1957) with and without recourse to the Wick rotation respectively.
Angular Correlation Measurements in 57Fe
Authors: Taylor RB , Hille F
Published: June 2011

The results of two y-y correlation measurements following the thermal capture of neutrons in 57Pe are presented. The spin of the 1'725 MeV state is found to be 3/2- and that of the 1�627 MeV state to be 3/2-(5/2-). The mixing ratios for the decay of the two states have been calculated.
Raman Processes in the Helium Atom in Intense Fields
Authors: Thareja RK , Mohan Man , Nayak V , Haque SN
Published: June 2011

Using the hydrogenic model for the helium atom, the amplitude of transition from states He(ls) to He(ls, nl) by absorption of N photons of an intense field together with the emission of one Raman photon is evaluated. From the general expression for the transition amplitude, the particular case of transition from He(ls) to He(ls, 2p) is considered. The 'reduced' transition amplitude is plotted against the number of photons N involved and against the intensity parameter y st;parately. It is found that the s wave contributes maximaly to the transition amplitude. An important feature of the calculations is the appearance of nonlinear behaviour at high intensity. The dominance of higher order processes over lower ones at high intensity is also found.
Debye?Waller Factors of a-Iron and Sodium
Authors: Prakash Jyoti , Pathak LP , Hemkar MP
Published: June 2011

The Debye-Waller exponents for oc-iron and sodium are calculated at different temperatures using the Behari-Tripathi (1969) modified angular-force model, which takes into account the effect of electron-ion interactions. The computation uses Blackman's sampling technique. The results are compared with existing experimental data. They are found to agree satisfactorily up to a certain temperature, above which they become progressively lower than the corresponding experimental values.
Three-wave Interactions Involving One Whistler
Authors: Melrose DB
Published: June 2011

Three-wave interactions in which one of the waves is a whistler and the other two are higher frequency waves are examined. The suggestion by Chiu (1970) and Chin (1972) that radio emission near the fundamental plasma frequency might arise in the solar corona from the coalescence of a whistler wave with a Langmuir wave is shown to be unacceptable because the resonance condition for the three-wave interaction cannot be satisfied.
Quantization of Fields in Accordance with Modular Statistics
Authors: Green HS
Published: June 2011

A new generalization of quantum statistics is described, which is different from parastatistics, though it includes Fermi statistics and parafermi statistics of order two. It can be applied to the quantization of nonlinear field theories, without violating the correspondence principle. Like parastatistics, it allows the occupation of a given dynamical state by more than one particle of half-odd-integral spin. A special feature is that quark-like particles are naturally associated in modules, which have many of the characteristics of baryons and mesons. The group theoretical properties of the new statistics, and the implied classification of states, are briefly examined.
A Particle?Hole?Rotator Coupling Model for the Giant Resonance of Carbon-12
Authors: McDougall Anne , Spicer BM
Published: June 2011

A collective correlations calculation has been made for the giant resonance of 12C. The low-lying states are treated as members of two rotational bands, and higher energy low-lying states are included in the coupling procedure in an attempt to examine the connection of these states with structure in the 30--35 MeV region, and to examine a proposed rotational band of states built on the 7�65 MeV (0+) level. The calculation fails to transfer strength to the extent expected.
Total Yield Measurements in 23Na(p, g)24Mg
Authors: Switkowski ZE , O'Brien R , Smith AK , Sargood DG
Published: June 2011

The reaction 23Na(p, y)24Mghas been investigated in the proton energy range 0'25-2�5 MeV. Total "..ray strengths were determined for 64 resonances. A yield curve was measured over the range 0�65-2�55 MeV, and an estimate of the nonresonant cross section was obtained. Total resonance widths were deduced for 32 levels.
Recombination Lines near 8·9 GHz of Strong Sources in the Southern Milky Way
Authors: McGee RX , M Newton Lynette , Batchelor RA
Published: June 2011

Seventeen intense nebulae in the southern Milky Way have been surveyed for their radio recombination lines of hydrogen and helium, H 90IX, He 9OIX, H 113ft, H 129y, and of elements heavier than helium, X901X. The H901X line for 30Doradus in the Large Magellanic Cloud was also observed. Data on source size, flux density, continuum temperature, line temperature, line half-width and radial velocity are used to derive information about the sources. This information includes electron temperatures and turbulent velocities, the abundance ratio of singly ionized helium to ionized hydrogen, and the intensity ratios of ft and y lines to IX lines. The lines from elements heavier than helium are discussed.
6Li( d, d'): Direct Breakup Effects and Parameters of the First 2+ Level of 6Li
Authors: Bray KH , Frawley AD , Ophel TR , Treacy PB
Published: June 2011

The reaction fiLi(d,d') has been used to populate the first J" = 2+ level of fiLi. To obtain level parameters, use has been made ofa reaction theory which allows for direct breakup effects. The width obtained is 1� 82�O'1l MeV, which is consistent with results of 4He+d scattering experiments, though some detailed discrepancies remain unexplained. The position of the level is found to be 4�32�O�04 MeV.
The Parkes 2700 MHz Survey (Ninth Part). Supplementary Catalogue for the Declination Zone ?45° to ?65°
Authors: Wall JV , Shimmins AJ , Bolton JG
Published: June 2011

A catalogue of 166 radio sources is presented, covering an area of 0�63 sr with right ascensions 0Qh to 03h, 04h to OSh 30"', 17h 30'" to 19h and 20b to 23h between declinations -45� and - 65�. The regions omitted are either close to the galactic plane (OSh 30'" to 17h 30"') or are covered in the third part of the Parkes 2700 MHz survey. The catalogue was compiled from a 'fast' finding survey at 2700 MHz aimed at detecting sources stronger than o� 5 Jy. Subsequent measurements at 2700 and 5009 MHz of flux density and position were made for all sources which were not in the Parkes 40S MHz catalogue and for 42 sources in the 40S MHz catalogue for which only data of low accuracy were available.
The Parkes 2700 MHz Survey (Tenth Part). Supplementary Catalogue for the Declination Zone +4° to +25°
Authors: Shimmins AJ , Bolton JG , Wall JV
Published: June 2011

A catalogue of lSI radio sources is presented covering the declination zone +4� to +25� and all right ascensions, omitting two regions within approximately 10� of the galactic plane (R.A. 05h30'" to 07ho()m and R.A. lShOO'" to 2Oh30"'). The catalogue was compiled from a 'fast' finding survey at 2700 MHz aimed at detecting sources stronger than o� 5 Jy. Subsequently, measurements of accurate flux density and position were made on all the sources which were not in the Parkes 40S MHz catalogue and on a few sources in the 40S MHz catalogue for which only data of low accuracy were available. The' positions of sources were determined to an accuracy of 10" arc r.m.s. in both coordinates. Flux densities for most of the sources were also measured at 5009 MHz. Identifications are suggested for 17 galaxies and 62 quasi-stellar objects.
Australian Journal of Physics Astrophysical Supplements
Authors: Gardner FF , Whiteoak JB , Morris D
Published: June 2011

The results of surveys made at Parkes of linear polarization at wavelengths of 6, 11, 18 and 21 cm are presented for a total of 1121 small-diameter radio sources or source components
Dynamical Consequences of a Photon Regge Trajectory
Authors: Joshi GC
Published: June 2011

It is argued that the newly discovered narrow resonances are Regge recurrences of the photon Regge trajectory. The widths and masses are calculated using the Anselm-Gribov technique, taking the data on the 3�1 GeV resonance as an input.
pp Elastic Scattering and the Pomeron Periphery
Authors: Saleem Mohammad , Rafique Mohammad , L Mir Khalid , Mirza JS , Tirmazi SH
Published: June 2011

It is shown that, in pp elastic scattering at ISR (intersecting storage ring) energies, a dip at t ~ -1�3 (GeV/c)2 and a bump at t ~ -2'0 (GeV/c)2 in the differential cross section, as well as a break at t ~ -0,1 (GeV/c)2 in the slope parameter, can be explained by a peripheral pomeron.
Model Pseudopotentials and Dynamical Properties of Simple Metals
Authors: Srivastava SK
Published: June 2011

The pseudopotential investigation of the dynamical properties of simple metals is discussed, and various model pseudopotentials are used to determine the thermal resistivity as a function of temperature at constant volume for the b.c.c. metals Li, Na, K, Rb, and Cs and the f.c.c. metals Cu, Ag, and Au. Krebs's (1965) lattice dynamical model is used to supply dynamical structure factors. The resulting theoretical thermal esistivities are compared with available experimental values.
On a Class of Exact Spherically Symmetric Solutions to the Einstein Gravitational Field Equations
Authors: Cook MW
Published: June 2011

This paper presents a development of a well-known class of Einstein gravitational fields which describe, in comoving coordinates, spherically symmetric perfect fluids with spatially uniform density but with nonuniform pressure. It is noted that the sign of the spatial curvature or these distributions may vary with time, in contrast with the situation for the uniform model theory used in most cosmological applications. It is shown, however, that this entails physically unacceptable behaviour of the fluid. In conclusion there is given a preliminary investigation of isolated fluid spheres, and a description of their noncovariant 'spatial geometry' is discussed.
Corrigendum: Parity-nonconserving Effects in n-p Capture at Thermal Energies
Authors: R Lassey Keith , HJ McKellar Bruce
Published: June 2011

As a result of discussions which one of us (B.H.J.McK.) has had with B. Desplanques and H. J. Pimer, we have discovered an error in sign in some of our results: all numerical values of As, At, C, Py and Q( are of the wrong sign: This error is due, in part, to a misunderstanding of Danilov's (1965) paper, in which his relative momenta are defined as
The Use of X-ray Interferometry to Measure X-ray Refractive Indices
Authors: Creagh DC
Published: June 2011

A Laue-case X-ray interferometer has been constructed to enable the measurement of X-ray refractive indices for X-ray wavelengths ranging from Ag Krx.1 to Fe Krx.1. Refractive indices have been measured for some alkali and alkaline-earth halides. From these the real part of the X-ray forward scattering amplitude I!J.f~ has been calculated for each atomic species. Comments are made on the validity of some of the assumptions made in quantum mechanical estimations of I!J.f~.
Static Charged Dust Distribution in the Brans-Dicke Theory
Authors: Nayak BK
Published: June 2011

The distribution of static charged dust in the Brans-Dicke theory is considered. It is shown that the ratio of charge density to mass density is related to the scalar interaction '" so that for small values of '" the charge density will far exceed the mass density. This result suggests that the existence of a finite electron can be realized in the Brans-Dicke theory of gravitation through a static charged dust distribution.
Intensity Distribution of Interplanetary Scintillation at 408 MHz
Authors: Milne RG
Published: June 2011

It is shown that interplanetary scintillation of small-diameter radio sources at 408 MHz produces intensity fluctuations which are well fitted by a Rice-squared. distribution, better so than is usually claimed. The observed distribution can be used to estimate the proportion of flux density in the core of 'core-halo' sources without the need for calibration against known point sources.
A Continuous Spectrum Analyser for Analogue Analysis of ULF Tape Recorded Data
Authors: McNabb PW , Fraser BJ
Published: June 2011

A sweep-frequency spectrum analyser for Pel geomagnetic pulsations (0�2-5 Hz) is described. It utilizes a rotating head assembly with two replay heads for scanning the data tape which is transported by a standard audio frequency quarter-inch tape deck. Frequency and time resolutions of O� 1 Hz and 6 s in the Pel band may be obtained.
Australian Journal of Physics Astrophysical Supplement
Authors: Clark DH , Caswell JL , J Green Anne
Published: June 2011

High-resolution contour maps of surface brightness at 408 and 5000 MHz are presented for 28 new galactic SNRs.
Experimental Observations of the Diffusion Cooling of Electrons in Argon
Authors: Rhymes T , Crompton RW
Published: June 2011

The cooling by diffusion of electrons in argon and in argon–hydrogen mixtures has been studied by the Cavalieri density sampling technique. In the case of argon, the measured values of the reduced diffusion coefficient ND varied by more than a factor of two over the pressure range 2–8 kPa. When small quantities of hydrogen were added to the argon, the cooling effect was reduced due to the increased energy transfer between the electrons and gas molecules. For argon, the magnitude and pressure dependence of ND are in satisfactory agreement with the recent calculations by Leemon and Kumar (1975).
Magnetization of Micron Sized Magnetite Particles
Authors: Parry LG
Published: June 2011

Approximately equidimensional particles of magnetite of about 1 JlIll in length contain domain patterns which are severely restricted by the small particle size. Measurements have been made of the thermoremanent and hysteretic properties of samples containing small magnetite grains, which had been separated to avoid strong interparticle interactions. The experimental results are compared with predictions based on current theoretical models.
How Isotopes Obscure the Anisotropic Phonon Umklapp Scattering in Dielectrics
Authors: Hudson PRW , Bomers MC , Fyans RA
Published: June 2011

Calculations of the thermal conductivity of h.c.p. 4He, doped with up to 1 % 3He, are presented using a Debye relaxation-time approach. The results are analysed to extract information on the exponents in the anisotropic phonon Umklapp relaxation rate. The results show that even if 1 % of 3He is present the exponents may be measured to within 7 % of their undoped value. Consequently, anisotropic phonon Umklapp parameters may be determined in crystals where natural isotopes exist
On the Extended Forms of Phenomenological Models for the Lattice Dynamics of BCC Transition Metals
Authors: Gohel VB , Jani AR
Published: June 2011

The Sharma-Joshi and Krebs phenomenological models for the lattice dynamics of cubic metals have been extended and are applied to study the phonon dispersion curves of tungsten, a metal for whlch long range forces are also important. It has been found that, unlike extended forms of the de Launay model (Shukla and Cavalheiro 1973a) for certain cubic metals, the models studied here for b.c.c. transition metals are not always adequate. Possible reasons for the shortcomings of the results are pointed out and discussed. The role of angular forces, particularly when they are used along with a fairly good conduction electron-ion interaction term, has been examined and found to be unimportant
The Nature of the Ionic Bond
Authors: Thakur KP
Published: June 2011

A new model to describe interionic binding in diatomic crystals is proposed. With the inclusion of an overlap repulsion of logarithmic form along with charge-charge and van der Waals interaction terms, the model is found to yield improved values for the cohesive energy and other parameters of alkali halide crystals. Unlike previous forms for the interionic binding in an LiF crystal, in which the potential is negative at distances much smaller than the distance of closest approach of Li + and F- ions, the present model tends to infinity in the positive energy region before such distances are approached
The Propagation of Spherical Vortices
Authors: Manton MJ
Published: June 2011

A model based on dimensional arguments is presented in order to predict the propagation velocity of the entrained fluid of a neutrally buoyant spherical vortex. The model vortex is characterized by single length and velocity scales. Its behaviour is considered in the two limiting cases of zero and infinite Reynolds number. Comparison of predictions from the model with experimental observations suggests that all stable vortices can be characterized by these two cases.
An Evolutionary Model for Quasars
Authors: V Zotov Natalia , Davidson W
Published: June 2011

A simple, though not necessarily unique, model for the cosmic population dynamics of quasars is presented. This model incorporates a double evolutionary trend: (i) a strong luminosity evolution, the presence of which we have discussed previously (Zotov and Davidson 1970, 1973) and (ii) an evolution of total coordinate density. This double trend is the same as that already found to be applicable to the total radio source population, if account is taken only of radio characteristics (Davidson et at. 1971). The predictions of the scheme are compared with five sets of data, covering a wide range of frequencies and flux density limits, and they are found to give good agreement in all cases.
Effects of Rotation on a Test Particle in the NUT Field
Authors: Karade TM , Rao JR
Published: June 2011

The geodetic motion of a test particle in the NUT (Newman et al. 1963) field is investigated and the rotational effects are deduced. The behaviour of particles and light near the Schwarzschild singularity points is also considered.
Nonstatic Spherically Symmetric Solutions for a Perfect Fluid in General Relativity
Authors: Chakravarty N , Dutta Choudhury SB , Banerjee A
Published: June 2011

A general method is described by which exact solutions of Einstein's field equations are obtained for a nonstatic spherically symmetric distribution of a perfect fluid. In addition to the previously known solutions which are systematically derived, a new set of exact solutions is found, and the dynamical behaviour of the corresponding models is briefly discussed.
Fission Product Mass Yield Curves and Their Energy Dependence
Authors: Cook JL , Rose EK , Trimble GD
Published: June 2011

It has been found that the mass yield curves for 232Th, 233U, 235U, 238U and 239pU neutron fission can be fitted, with an accuracy of better than 20 %, by the superposition of two pairs of asymmetric gaussian curves and a single symmetric gaussian curve. The parameters of the fit have been investigated as a function of the nuclear temperature at the saddle point of the fissioning compound nucleus, and the widths and positions are found to vary linearly with this temperature. In addition, broad peaks are found in the weights of the gaussians, the weights being related to partial fission cross sections. This empirical analysis has been compared with the predictions of the Nix (1969) model of fission and deficiencies in the existing theory are discussed.
A Search for an Excited Kp=0+ Rotational Band in 24Mg
Authors: Branford D , Carlson LE , Huang FCP , Gardner N , Ophel TR , Wright IF
Published: June 2011

A search is described for an excited Kn = 0+ rotational band based on the 6� 44 MeV level of 24Mg. Mean nuclear lifetimes have been measured by the Doppler shift attenuation method using the 12C('60,a)24Mg reaction and the results are 't'm = 66�29, 28�7 and 13�3 fs for levels at 6'44, 8�65 and 10� 58 MeV respectively. The absolute transition rates found for the y decays from the 6�44 and 8�65 MeV levels are in good agreement with the results of shell model calculations if it is assumed that these levels are the 0+ and 2 + members respectively of the excited Kn = 0+ rotational band. Based on this assumption, a result Qoo = 0�48 �0�08b is obtained for the intraband quadrupole moment. From a study of the 23Na(p, y) reaction, it is established that the J = 4 levels at 12� 63 and 13�05 MeV do not decay by enhanced E2 transitions to the 8� 65 MeV level. This suggests that neither of these levels is the 4 + member of the excited Kn = 0+ rotational band. An assignment of J" = 4+ is made to one member of the doublet at 10�58 MeV.
A Long-range Ocean Radar for Ocean Surface Studies using Backscatter Via the Ionosphere
Authors: Ward JF , Dexter PE
Published: June 2011

An HF Doppler radar, designed for use at long range via an ionospheric propagation mode, has been developed primarily for the determination of wave states over large ocean areas. The operating frequency is 21 �840. MHz, and the array is physically rotatable through a full 3600 of azimuth, thus allowing for great flexibility in the choice of target area. The experimental technique utilizes a well-known resonance interaction mechanism for electromagnetic waves backscattered from a moving sea wave surface to derive sea state parameters in the scattering region for input to oceanographic and meteorological synoptic data networks. An ultimate angular resolution of less than 10 of azimuth, coupled with high operational flexibility, suggest possible utilization of the aerial array for tracking and interrogating free-floating ocean buoys, tracking radio noise associated with tropical cyclones and investigating aspects of ionospheric dynamics.
Massive Scalar Field: Source of the Graviton and 'Strong Gravity'
Authors: Rao JR , Tiwari RN , Nayak BK
Published: June 2011

An exact class of nonstatic spherically symmetric solutions is obtained for the Einstein field equations with a massive scalar field as source. The solutions are found to characterize the 'strong gravity' associated with elementary particles, and it is shown that Ivanenko's (1965) massive graviton possesses zero spin.
Ion Currents, Ion-Neutral Collisions and Plasma Transport Phenomena
Authors: Millar DD
Published: June 2011

It is pointed out that, in the commonly encountered plasma configuration of perpendicular electric and magnetic fields, the Pedersen current (in the E direction) is carried by thtl ions, the Hall current (in the E x B direction) is carried by both ions and electrons in nearly equal and mutually canceling parts, and the Birkeland current (in the B direction) is carried by the electrons. One of the consequences of the ion current's existence is that the massive ions are accelerated directly by the fields and not, as in a metallic conductor, through momentum transfer from the electrons. Another is that in the presence of a third neutral component of a partially ionized plasma, again a commonly encountered situation, the electron component of the plasma may be in effect collisionless, the ion component collision-dominated, and the plasma resistivity may then be expected to differ markedly from the resistivity calculated on the basis of Coulomb collisions between electrons and ions. It is shown, for example, that the current structure of an ionizing shock may be adequately explained in terms of an ion-carried current subject to a resistivity, determined solely by ion-neutral collisions, of value two orders of magnitude greater than the Coulomb-collision resistivity. In this, as in the other similarly affected plasma transport phenomenon of diffusion, there is no anomaly nor is there need to invoke plasma instability or fluctuation theory for further explanation.
Analysis of Eu2+ Spin-Hamiltonian Parameters
Authors: Newman DJ
Published: June 2011

The superposition model is used to determine single-ligand spin-Hamiltonian parameters for Eu2+ in a range of host crystals. The properties of these parameters are shown to be generally similar to those of the corresponding parameters for Gd3+, although some striking differences occur in their relative magnitudes and distance dependence. Both the similarities and the differences confirm aspects of a previous interpretation of the spin-Hamiltonian parameters for f7 8S7/2 ground states.
The Structure and Dynamic Instability of Isothermal Relativistic Star Clusters
Authors: D Fackerell Edward , G Suffern Kevin
Published: June 2011

The structure and dynamic stability of isothermal relativistic star clusters are discussed both for the case of clusters without dispersion in stellar rest mass and for two families of clusters with dispersion in stellar rest mass. We show that the former are dynamically unstable if the central redshift is greater than about 0'5, and that the latter are dynamically unstable if the central redshift is greater than about O' 6, so that the inclusion of dispersion in mass does not greatly affect the stability of isothermal relativistic star clusters.
Radio Continuum of the Small Magellanie Cloud at Wavelengths 6 and 3·4 cm
Authors: McGee RX , M Newton Lynette , Butler PW
Published: June 2011

The radio continuum at wavelength 6 cm has been surveyed in the direction of the Small Magellanic Cloud with a telescope beam of 4'�1 arc. Only 27 radio sources have been delineated in this galaxy, and details of their positions, flux densities and spectral indices are given. Some supporting observations were made of the stronger sources at 3�4 cm wavelength. The distribution of the 6 cm emission is compared with the distributions of the ionized gas and neutral hydrogen.
The Reaction e+ e- ?h'(X°)g and the New Vector Mesons
Authors: Chandramohan T , Achuthan P
Published: June 2011

The generalized vector meson dominance theory of Sakurai is used to study the production of 1'1' mesons in electron-positron collisions. The differential and total cross sections are calculated, especially taking into account contributions from the new vector mesons p'(l250) and p"(l600). The influence of an SU(3) symmetry-breaking parameter f3 on the numerical results is also investigated
Gamma Ray Intensity and Angular Correlation Measurements in 160Dy
Authors: Bhati SS , Singh Nirmal , Bajaj PD , Trehan PN
Published: June 2011

Gamma-ray intensity measurements in 160Dy have been carried out using a Ge(Li) detector. In addition, 1'-1' angular correlation measurements have been made on 10 cascades in 160Dy using a Ge(Li)-NaI(TI) fast coincidence arrangement. These cascades are 299 ..... 966, 299 ..... 879, 879 ..... 87, 197 ..... 87, 962 ..... 87, 21S ..... 962, 299 ..... (879) ..... 87, 299 ..... (682) ..... 197, 21S ..... (962) ..... 87 and 21S ..... (76S) ..... 197 keY. Of these, the 21S ..... (962) ..... 87 and 21S ..... (76S) ..... 197 keY cascades have been measured for the first time. The multipolarities of the 197, 21S, 299, 879 and 962 keY transitions were found to be E2+(0'2�0'2)%M3, El +(2'S~~:g)%M2, El +(2~~)%M2, Ml +(99�1)%E2 and Ml + (98 � 1) % E2 respectively.
Vorticity of a Perfect Fluid Undergoing a Gravitational Collapse
Authors: Mason DP
Published: June 2011

The vorticity propagation equation for a perfect fluid in general relativity is derived in a form which is the same as that of Maxwell's equation for the magnetic field four-vector in relativistic magnetohydrodynamics. Starting from this result, an expression for the change of vorticity during a gravitational collapse is obtained in terms of the spatial geometry, using a procedure similar to that introduced by Cocke (1966) in relativistic magnetohydrodynamics. It is assumed that the equation of state of the fluid is p = 1Xp" where IX is a constant and p, is the total proper energy density. If t < IX :s;; 1, it is found that the vorticity tends to zero during an isotropic collapse, in agreement with a result obtained previously by Ellis (1973) using a different procedure. Nonisotropic collapses are also considered. The dynamical importance of vorticity in a gravitational collapse is examined by considering the behaviour of w2 /p,.
Effect of Voigt-Palacios-Gordon Transformations on Thermodynamic Quantities
Authors: Karade TM , Borikar SM
Published: June 2011

The effect of transformations of Voigt-Palacios-Gordon type on thermodynamic quantities is considered. It is found that, while most quantities behave as they do under a Lorentz transformation, the pressure is, surprisingly, not invariant.
Nuclear Sum Rules, Electron Scattering and Giant Resonances
Authors: Tassie LJ
Published: June 2011

The isoscalar sum rules of Deal and Fallieros (1973) and generalizations of these sum rules are discussed. The isoscalar form factor and transition density for an arbitrary eigenstate of the nucleus are given as sums over the sum rules and, for a particular choice of the operators in the sum rules, are given by a series of which the first terms are the same as the results of the hydrodynamical model. It is shown that caution is needed in making nuclear spin assignments from inelastic electron scattering. The sum rule of Deal and Fallieros is used to clarify the calculation of Bohr and Mottelson (1975) of the energy of the isosca1.ar giant quadrupole resonance.
A Numerical Solution of Wave Equations for Real or Complex Eigenvalues
Authors: Clayton E , Derrick GH
Published: June 2011

A simple but efficient computational procedure is given for calculating either real or complex eigenvalues of wave equations. The method is based essentially on the 'outgoing-waves-only' criterion and enables one to use both short and long range potentials. The technique is illustrated by its application to scattering states of the square well potential.
Angular Correlation Measurements in 33S
Authors: Southon JR , Poletti AR , Beale DJ
Published: June 2011

The 32S(d, p) reaction has been used to excite states in 33S. Proton-gamma angular correlations for states up to 4�43 MeV in excitation energy have been measured to determine spins and y-ray branching and multipole mixing ratios. Results obtained for mixing ratios include 0(1� 97-+0) = 0'75�0'38, 0(2'93-+0) = 0�19�0�14 and 0(2'93-+1'97) = O�OO�O�04. Spin and parity assignments of 3/2 + and (1/2+, 3/2�) have been found for the 3� 94 and 4�43 MeV states respectively. Branching ratios have been determined for several previously unreported weak decays from high energy states.
Drift Velocities of Low Energy Electrons in Argon at 293 and 90 K
Authors: Robertson AG
Published: June 2011

The drift velocity of electrons in argon has been measured at 90 K in the range 0�002 ,;;; E/ N (Td) :.;; 0�7 and at 293 K in the range 0�01 ,;;; E/N (Td) ,;;; 1�0. The high sensitivity of the drift velocities to the presence of small quantities of diatomic impurities, particularly nitrogen, was demonstrated by adding known but trace quantities of diatomic gases. In this way it was observed that the presence of 6 p.p.m. nitrogen in the argon gave errors in the drift velocity of up to 3 %. As a result it was necessary to purify research grade gas before use. A full discussion is given of the errors incurred in the measurements.
The Momentum Transfer Cross Section for Electrons in Argon in the Energy Range 0 - 4 eV
Authors: Milloy HB , Crompton RW , Rees JA , Robertson AG
Published: June 2011

The momentum transfer cross section for electron-argon collisions in the range 0–4 eV has been derived from an analysis of recent measurements of DT/μ as a function of E/N at 294 K (Milloy
and Crompton 1977a) and W as a function of E/N at 90 and 293 K (Robertson 1977). Modified effective range theory was used in the fitting procedure at low energies. An investigation of the range of validity of this theory indicated that the scattering length and effective range were uniquely determined ,and hence the cross section could be accurately extrapolated to zero energy. It is concluded that for ε ≤ 0.1 eV the error in !he cross section is less than � 6 % and in the range 0.4 ≤ ε (eV) ≤ 0.4 the error is less than � 8 %. In the range 0.1 < ε (eV) < 0.4 the presence of the minimum makes it difficult to determine the errors in the cross section but it is estimated that they are less than −20 %, +12 %. It is demonstrated that no other reported cross sections are compatible with the experimental results used in the present derivation.
On the Validity of the Two-term Approximation in the Solution of Boltzmann's Equation for Electron Motion
Authors: Milloy HB , Watts RO
Published: June 2011

Monte Carlo techniques have been used to study the validity of the two-term spherical harmonics expansion for the distribution function for electrons moving through a gas under the influence of a constant electric field and undergoing elastic collisions with the gas particles. The validity of the expansion was studied by comparing simulated values of the electron drift velocity, lateral diffusion coefficient and mean energy with the values predicted by the conventional theory. From the results of the simulations and from general considerations it is� argued that, if the momentum transfer cross section is related to the electron energy by a power-law dependence, then the two-term approximation is equally valid at all EIN. It is shown that the presence of a minimum in the cross section can render the two-term approximation invalid. However, the conditions under which the approximation is invalid do not correspond to any known electron-atom combination and it is concluded that, if only elastic scattering occurs, the two-term approximation is valid for electron motion in helium, neon and argon.
Evidence for Two-step Processes in Photonuclcar Reactions
Authors: Spicer BM
Published: June 2011

The measurement of de-excitation )' rays following photodisintegration allows the identification of specific entrance and exit channels in these reactions. From studies of de-excitation )' rays in three separate cases, examples are cited of reactions which, on the basis of nuclear structure arguments, proceed via two-step processes.
Vibrational Excitations in the Even-mass Cadmium Isotopes
Authors: Spear RH , Warner JP , Baxter AM , Esat MT , Fewell MP , Hinds S , Joye AMR , Kean DC
Published: June 2011

The backward-angle scattering of 4He ions from the even-A stable isotopes of cadmium has been investigated at bombarding energies above the Coulomb barrier. At 17� 5 MeV bombarding energy the gross features of the spectra are strikingly regular from one isotope to another, and this may be interpreted in terms of vibrational excitations. Other evidence is presented to support the concept of a uniform vibrational character for all the even-A stable cadmium isotopes. The spectra show no significant evidence for previously unreported levels in the two-quadrupole-phonon excitation region. However, a new level is found at 2304 � 4 keY in l06Cd.