bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Composite Spectral?Sensitivity Functions
Authors: Anderson JS , Faulkner EA , Klemperer DF
Published: May 2011

In measurem mts of the photoelectric effect on semiconductors two types of relationship ]uwe boen found between the frequency of incident radiation v and the obsenlld photoelectric current lobs. In one type, the plot of log lObs against v fits th( theoretical Fowler curve (Fowler 1931) ; in other cases, however, a curve is obtained which is in two parts, each of which can be fitted to a separate Fowler curvc. Thus Suhrmann, Wedler, and Dierk (1958a, 1958b) obtained " composite" curves from bismuth films, and we have found both types of behaviour with evaporated nickel films undergoing stepwise oxidation. The problem of interpreting such composite curves is quite a general one.
The Extended Component of Centaurus A
Authors: Wade CM
Published: May 2011

The strong southern radio source Centaurus A (lAU 13S4A) was one of the first to be identified with an optically observable object. Bolton, Stanley, and Slee (1949) suggested that the radio emission was associated with the peculiar galaxy NGC 5128, and this identification has been strengthened by more recent positional measurements (Mills 1952). NGC 5128 is a most unusual object, appearing to be a spheroidal galaxy transected by a heavy belt of obscuring matter (Baade and Minkowski 1954a; Sersic 1958). Its distance is uncertain, but it is likely to be about 1 megaparsec away (Baade, personal communication).
Measurements of Changes in the Phase Path of Radio Waves Reflected from the Ionosphere at Normal Incidence
Authors: McNicol RWE , Thomas JA
Published: May 2011

Fixed-frequency measurements were made at Brisbane, using pulse transmissions,
of the changes in phase of radio waves i'eceived after reflection at normal incidence
from the various ionospheric layers. Because of the homodyne detector used, such
phase-path records have a very good signal-to-noise ratio, Also, due to the difference
in behaviour of echoes of different polarization or from different ionospheric layers,
the effective resolution is high. When the echoes had a well-defined phase, the rate
of change of phase path with time was measured; the slowest rates were for smooth
night-time Es layers, when values as low as I m sec-1 were sometimes found, whereas
for the night-time F. region the rates were usually in the range 10-40 m sec-l. Records
were also made of reflections from drifting Es clouds, and of the effect of underlying Es
ionization on reflections from the F. region.
Experimental Relations Between Ionospheric True Height, Group Height, and Phase Height
Authors: Thomas JA , McNicol RWE
Published: May 2011

Computations of ionospheric phase height at a particular frequency have been made using true height analyses of h'f curves. Temporal changes in these computed values agree well with experimentally measured changes of phase path both in the case of regular diurnal variations and during an eclipse. The true height analyses are thus shown to be experimentally reliable, and at the same time we can allot an " absolute" value to the normal phase-path records.
The Lifetime and Cell Size of the Granulation in Sunspot Umbrae
Authors: Loughhead RE , Bray RJ
Published: May 2011

High quality photographs extending over a period of 2 hr 11 min have been obtained of the granulation in the umbra of a large sunspot. In agreement with earlier work, the mean cell size of the umbral granulation is found to be significantly less, and the lifetime considerably greater, than that of the photospheric granulation. Ten per cent. of the umbral granules last for over 2 hr.
The Characteristic Electron Energy Loss Spectra of Aluminium?Magnesium and Aluminium?Copper Alloys
Authors: Powell CJ
Published: May 2011

The characteristic electron energy loss spectra of 1500 eV electrons scattered by aluminium-magnesium and aluminium-copper alloys have been measured. A plasma and a lowered plasma energy loss were observed in the alloys, and it was found that surface oxidation caused the disappearance of the lowered plasma loss and the appearance of a new modified lowered plasma loss. Though the compositions of the evaporated alloy specimens were unknown, the three energy losses were observed to vary continuously between the values observed for the three elements. This continuous change can be interpreted in terms of the changing free electron density in alloys of varying composition. It is concluded that measurements of the characteristic loss spectra of alloys can differentiate between losses due to individual and collective electron excitation.
Ionospheric Refraction in Radio Astronomy. I. Theory
Authors: Komesaroff MM
Published: May 2011

Expressions are derived for the apparent displacements of cosmic radio sources at transit resulting from ionospheric refraction. The derivation takes account of horizontal electron density gradients whose effects often outweigh the refraction expected from a spherically symmetrical ionosphere. .
Hyperfine Structure in the Microwave Spectrum of Water. II. Effects of Magnetic Interactions
Authors: Posener DW
Published: May 2011

Further analysis of the hyperfine structure appearing in the observed microwave spectra of HDO and D.O, taking into account nuclear quadrupole and magnetic dipole interactions, leads to a complete determination of the electric field gradient tensor at the hydrogen nuclei in the water molecule, giving a value along the bond direction of (+ 1� 59 �O� 04) X 1015 e.s.u.
On the Flow and Exchange Diffusion of Electrons and Negative Ions Formed by Molecular Attachment
Authors: Kauman WG
Published: May 2011

Formation of negative ions by attachment of electrons to molecules was first recognized by Thomson (1916). Huxley (1959) recently discussed the steady-state structure of a stream of electrons and ions drifting and diffusing in a gas, taking account of ionization by molecular attachment.
Magnetic Anisotropy of Dispersed Powders
Authors: Stacey FD
Published: May 2011

It is well known that in most rocks the ferromagnetic fraction occurs as small grains dispersed in a solid, magnetically inert matrix. Recently the magnetic anisotropy of rocks and of chondritic meteorites has been subjected to detailed study by the torque-meter method, and, in an attempt to obtain a physical understanding of the shape and crystal alignments of grains which cause magnetic anisotropy in these natural bodies, a number of artificial specimens have been prepared. Iron, nickel, and magnetite powders were mixed into solidifying media and allowed to set in a cylindrical mould in a 10 kilo-oersted field. The torque curves of the resulting specimens reveal a surprising result. It appears that single crystal magnetic grains tend to string together along lines of forc~, thus producing strongly anisotropic specimens, only when the first magneto crystalline anisotropy constant of the ferromagnetic material is positive.
Electron Background in Nuclear Emulsions
Authors: Hopper VD , E Laby Jean
Published: May 2011

Since 1951 supplies of Ilford G5 electron sensitive nuclear emulsions have been flown by air to A.ustralia. In 1954 it was observed that some batches, when developed soon after arrival, showed an excess electron background which made them unsuitable for the cosmic ray work for which they were imported.
Thermoelectric Power of Dilute Copper and Silver Alloys
Authors: Blatt FJ , Garber M , Kropschot RH , Scott B
Published: May 2011

Measurements of the thermoelectric power of several dilute copper and silver alloys are reported. The thermoelectric powers of the alloys were measured between about 8 and 350 oK. The results have been analysed using the Mott-Friedel relation. We have found that good agreement between the calculated and measured thermoelectric powers can be obtained only if it is assumed that the absolute thermoelectric power of pure copper and pure silver consists of two contributions: one, .the usual f.t:ee-electron contribution and another, which is believed to be due to phonon drag_ This phonon drag contribution is of the correct magnitude and shows the expected temperature dependence. Moreover, the effect of alloying on the phonon drag contribution is in agreement with theoretical estimates.
The Lattice Thermal Conductivity of Alloys
Authors: Kemp WRG , Klemens PG
Published: May 2011

The lattice thermal conductivity of alloys at liquid helium temperatures yields information about the nature of the electron-phonon interaction, and about the density of dislocations. It appears that in copper, silver, and gold the electrons interact with transverse as well as with longitudinal lattice waves. The lattice conductivity also varies with alloy composition; it is not clear whether this variation should be ascribed to changes in the electron density or to the presence of dislocations, locked into stable configurations by the solute atom. If the latter view is adopted, the density of dislocations in annealed alloys is typically of the order of lOlD to 1011 lines/em".
Thermal Transport in Dilute Alloys
Authors: White GK
Published: May 2011

Experimental values of the thermal resistivity for a number of elements, including copper, silver, gold, argon, germanium, silicon, antimony, and bismuth, are compared with theoretical values deduced from the anharmonic coupling between lattice vibrations. For copper-, silver-, and gold�rich alloys experimental and theoretical data for scattering of lattice waves by point defects are compared.
The Intensity of Dielectric Absorption in Alkali Halides as a Function of the Concentration of Divalent Cation Impurities
Authors: Cook JS , Dryden JS
Published: May 2011

The dielectric absorption of sodium chloride containing calcium and potassium chloride containing strontium has been measured as a function of concentration of the divalent impurity. From the intensity of the absorption it is possible to estimate accurately the number of divalent impurity cations associated with positive ion vacancies so as to form dipoles.
The Interaction of Dislocations with Boundaries and Surface Films
Authors: Head AK
Published: May 2011

A digital computer programme for finding the equilibrium positions of a group of dislocations is applied to two problems of a different type from those considered previously. These are:
The Influence of Temperature and Strain Rate on the Flow Stress of Annealed and Decarburized Iron at Subatmospheric Temperatures
Authors: Basinski ZS , Christian JW
Published: May 2011

The influence of temperature and strain rate on the flow stress of annealed and decarburized iron in the stages of uniform deformation has been studied at temperatures down to 78 oK. The Cottrell� Stokes law is not obeyed in iron, and the results are explainable in terms of the strong Peierls-Nabarro force in this metal.
The Peierls?Nabarro Force and the Deformation of Iron and Steel
Authors: Louat N
Published: May 2011

Evidence for the existence of an appreciable Peierls-N abarro force in iron and steel is examined. It is concluded that the observed behaviour is unlikely to follow from the presently proposed mechanism of this force and that the observed frictional stress may arise as a consequence of dislocations being in pile-ups.
The Orientation Dependence of Work?Hardening in Crystals of Face-centred Cubic Metals
Authors: Clarebrough LM , Hargreaves ME
Published: May 2011

It is shown that the principal features of the observed orientation dependence of work-hardening can be accounted for in terms of the likelihood of formation. Of Lomer-Cottrell sessile dislocations in two directions in tb" primary slip plane. This is deduced from the known variation of resolved shear stress with orientation, for the possible secondary slip systems, and metallographic observations of slip and deformation bands.
The Plastic Resistance of Crystals
Authors: Gilman JJ
Published: May 2011

Evidence is presented in this paper to show that crystals present a pla8tic 'resistarwe to dislocation motion. This has been demonstrated by direct observations of dislocations in LiF crystals by Johnston and Gilman, and in Fe-Si crystals by Stein and Low. The plastic resistance is almost independent of dislocation velocity except at very high velocities. It is, however, strongly influenced by temperature, impurities, and radiation damage. In LiF crystals, the plastic resistance is much higher for glide on {100} planes than on {nO} planes.
Annealing Kinetics of Neutron?Irradiated Aluminium and Copper
Authors: Blewitt TH , Coltman RR , Klabunde CE
Published: May 2011

Activation energies for the annealing of copper and aluminium following reactor bombardment near 4 OK have been measured in the range from 10 to 40 OK. Both the change in slope method and the isothermal technique method were utilized with the assumption that a constant activation energy existed. Computations of the number of jumps involved from the measured activation energy result in an impossibly small number. It is obvious that the method for determination of the activation energies is not applicable, probably because of the non-uniqueness of the activation energy.
Small Angle Intensities from Double Bragg Reflections in Cold?Worked Metals
Authors: Warren BE
Published: May 2011

The small angle intensity from a cold-worked polygrained metal is treated in terms of double Bragg reflections. It is assumed that cold work breaks up the original grains into subgrains with varying orientations, such that a first reflection in one subgrain can be followed by a second reflection in another subgrain of the original grain. For an initial sample which is polygrained with random orientation, the small angle intensity resulting from cold work is given in absolute units in terms of two parameters; an average initial grain size G, and a subgrain correlation function p( ep) giving the distribution in orientation of subgrains with respect to any average subgrain of the original grain. Under favourable conditions, both of these quantities can be obtained from the small angle intensity curve. For polygrained metals, small angle scattering is a useful tool -for obtaining the subgrain correlation function peep), a quantity not obtainable from the usual high angle measurements.
Alternative Superconducting Ground States
Authors: Fisher JC
Published: May 2011

A comparison is made between (a) the trial ground state composed of a linear combination of normal state configurations in which individual electron states of opposite momentum and equal spin projection (k t, -k t) and (k t, -k t), abbreviated (kcr, -kcr), are both either occupied or unoccupied, and (b) the trial ground state with (k t , -k t ) pairing proposed by Bardeen, Cooper, and Schrieffer. The two trial states lead to identical thermodynamics as long as an average matrix element -V = < Vkle' >av is treated as a disposable parameter. They lead to similar coherence effects for ultrasonic attenuation and nuclear spin relaxation. They differ in that spin paramagnetism is predicted for (kcr, -kcr) pairing. Detailed knowledge of the electron-phonon interaction in superconductors seems at present inadequate to rule out either possibility for all superconductors.
Magnetic Bays at Macquarie Island
Authors: Robertson CS
Published: May 2011

Polar magnetic bays are the most striking feature of magnetic records obtained by the Australian National Antarctic Research Expeditions at Macquarie Island. Negative bays are more numerous than positive bays and have greater amplitudes and durations. As a rule, negative bays commence about magnetic midnight whereas positive bays commence about 5 hr earlier. A daily reversal in direction of the bayproducing currents is indicated and the time at which this reversal takes place appears to vary with the seasons. During magnetically disturbed periods the ratio H bay amplitude to Z bay amplitude increases, indicating a northward movement of the bay-producing currents. At the same time auroras seen from Macquarie Island lie further north in the sky than usual.
Motion of the Aurora and Magnetic Bays
Authors: Bond FR
Published: May 2011

Observations from the ANARE station at Macquarie Island show that the development of an auroral display is characterized by a slow northward drift, east to west longitudinal motion, and an associated positive bay in the horizontal component magnetogram in the evening hours. This is followed by a sudden change in structure of the aurora and appearance of a negative bay. The negative bay persists for some hours, accompanied by west to east longitudinal motion and slow southward drift of the aurora.
A Dynamo Theory of the Aurora and Magnetic Disturbance
Authors: Cole KD
Published: May 2011

A model of an aurora regarded as a plane slab of highly ionized air parallel to the geomagnetic field within the ionosphere is examined. The model is stable in the presence of a wind of neutral molecules which, blowing the slab across the geomagnetic field, generates an electric polarization field perpendicular to its faces and a current along its length. This current is concentrated in a small height range and is chiefly due to electron drift.
The Photodisintegration of Rare Earth Elements
Authors: Thies HH , Spicer BM
Published: May 2011

The neutron yields from praseodymium, terbium, and holmium have been measured as a function of bremsstrahlung energy, and from these the shapes of the respective cross sections have been deduced. For terbium and holmium, the cross section for photon absorption shows two peaks, in agreement with the predictions of both the hydrodynamic model and the independent particle model of the nuclear photoeffect in non-spherical nuclei. The case of praseodymium was treated as a control experiment, since this nucleus is nearly spherical. Its photon absorption cross section has only one peak, in agreement with expectation for a spherical nucleus. The results are discussed in terms of both the hydrodynamic model and the independent particle model. Values of the deformation parameter are deduced from the photodisintegration data and are compared with values obtained by other methods.
Meteor Height Distributions and the Fragmentation Hypothesis
Authors: Weiss AA
Published: May 2011

This paper is concerned with a comparative study of the incidence of fragmentation amongst bright and faint meteors, as disclosed by photographic measurements of heights and light curves of brighter meteors (visual magnitudes < +4), and by measured radioecho height distributions of faint meteors (visual magnitudes ~+6). The discussion is based on photometric and height data for sporadic and shower meteors obtained by Harvard and Canadian observers, and on radio-echo height distributions measured at J odrell Bank. Mean photographic light curves are shorter than predicted by evaporation theory, and there is a large residual scatter in the heights of maximum brightness after reduction to standard meteor velocity and brightness. Trail length is independent of reduced height, and also of velocity if this exceeds 25 km/sec; for slower meteors trail lengths shorten rapidly. The radio�echo height distribution as a function of trail length is calculated for a simple model which incorporates these features of the ablation process for brighter meteors. Comparison with radio height measurements indicates that meteors below the photographic threshold show a closer approach to the predictions of the evaporation theory than meteors bright enough to record photographically.
On the Identification of Extragalactic Radio Sources
Authors: Mills BY
Published: May 2011

Identifications of radio sources with galaxies and clusters of galaxies have been sought systematically in a limited region of the sky. The optical data have been taken principally from the National Geographic Society-Palomar Observatory Sky Atlas and a catalogue of clusters of galaxies prepared by Abell (1958) from the same Atlas. The radio data are taken from results obtained with the Sydney cross-type radio telescope, supplemented at times with additional information from a recent Cambridge Catalogue (3C). A total of 46 possible identifications with galaxies are listed and 55 possible identifications with clusters of galaxies, the great majority of which are new. Most of these galaxies are double systems, but no other common features could be recognized: it seems probable that many galaxies of completely normal appearance are very strong radio emitters. The possible nature of the double galaxies is discussed briefly and attention is drawn to a corresponding duplicity in the radio brightness distribution observed in some strong radio sources. In many cases the emission from clusters appears to be associated with a single galaxy or pair of galaxies in the cluster; evidence for the existence of radiation of intergalactic origin is inconclusive. A selection of the possible galaxy identifications has been used to derive a provisional radio luminosity function; it appears probable that there is no distinct class of " radio galaxies", but all radio luminosities appear to be represented, the numbers of radio sources in a given volume of space falling rapidly with increasing luminosity. A radio luminosity function of the form derived is capable of accounting for a substantial number of the radio sources of small size observed at high galactic latitudes; the remainder could be accommodated by the uncertainty in the data. It is found that, at the levels to which source counts can currently be taken, cosmological effects are likely to be small, although the most distant sources are markedly affected.
Heterogeneous Nucleation by Aggregates of Particles
Authors: Head RB , Sutherland KL
Published: May 2011

The induction of a new phase by fine particles of a nucleating substance is complicated not only by variation in sizes but also by aggregation. The general effect of aggregation is to decrease the total number of particles but to reduce the supercooling (or supersaturation) necessary for growth of a new phase. Point contacts appear to be more fruitful than do line contacts, although both may be able to cause a substance to be more active than a large flat surface of the substrate. If the contact between particles is not a specially favoured position for nucleation, the aerosol as a whole appears to contain a higher proportion of active particles because of the persistence of initially active particles and the loss of less active ones.
Study of the Flare?Surge Event of September 7, 1958
Authors: M Lowman Karen , Billings DE
Published: May 2011

An approximate relation between luminosity distance D and Doppler shift a in cosmology is usually obtained by a succession of complicated expansions in series.
Geomagnetic Micropulsations
Authors: Ellis GRA
Published: May 2011

This paper describes simultaneous observations of geomagnetic micropulsations at three places ranging from 280 S. to 51 0 S. geomagnetic latitude. It is shown that there is no observable change in the micropulsation period with latitude although there is a monotonic increase in the amplitude with latitude for all periods between 10 and 100 sec. The interpretation of these results in terms of existing theories is discussed.
Photometric Observations of 5577 ? and 6300 ? Airglow During the I.G.Y.
Authors: Duncan RA
Published: May 2011

Twenty.one months' observation of the airglow from near Sydney, Australia, shows that (a) aurorae are detected 10� above the southern horizon at 6300 A whenever the magnetic disturbance index (K) reaches 5 but K must reach 7 before detection is certain at 5577 A; (b) the 6300 A zenith intensity increases rapidly with K once this equals or exceeds 4, but the 5577 A zenith intensity is independent of magnetic disturbance; (c) the zenith intensity of 5577 A tends to be a maximum at 03 hr local time; (d) the zenith intensity of 6300 A drops rapidly from dusk till 01 hr and then rises till dawn.
Vertical Characteristics of Travelling Ionospheric Disturbances
Authors: Heisler LH
Published: May 2011

The vertical dimensions of travelling disturbance phenomena have been investigated by derivation of the associated true height distributions of ion density. The height at which they appear often has an upper limit which may fluctuate in height from day to day.
The Radio Brightness of the Quiet Sun at 21 cm Wavelength Near Sunspot Maximum
Authors: Labrum NR
Published: May 2011

An investigation has been made of the radio emission from the quiet Sun at 21� 2 em wavelength in 1958 (near sunspot maximum). Two different methods have been used, both involving observations with very high angular resolution, to distinguish between the quiet-Sun component and the radiation from localized active regions. In one method, the Sun was scanned with a narrow pencil-beam; in the other, a fan-shaped aerial beam was used to give one-dimensional strip scans. In both cases it was necessary, when analysing the data, to take into account the residual effects of the very intense radiation from the localized sources. The two independent measurements gave results which agree within the limits of error. The apparent disk temperature was found to be approximately 140 000 oK, or twice the value for the same wavelength at sunspot minimum.
Granulation Near the Extreme Solar Limb
Authors: Loughhead RE , Bray RJ
Published: May 2011

Rosch (1957) found that on good photographs the photospheric granulation remains visible to within less than 10 sec of arc from the limb, and sometimes to less than 5 sec. Recently,however, these results have been contradicted by Edmonds (1960) who, on the basis of an examination of photographs obtained in "Project Stratoscope" (Schwarzschild 1959), finds that the granulation disappears almost completely at 6=75� (33 sec from the limb). Poor focus obliterates the last vestiges of the pattern closer to the limb; nevertheless, Edmonds concludes that the granulation disappears completely at 6=78� (21 sec from the limb). Since a determination of the distance from the limb at which the granulation disappears provides an estimate of the height of the top of the convection zone (Plaskett 1955; de Jager 1959), it is important to resolve this contradiction.
An Attempt to Detect Linear Polarization in the Galactic Background Radiation at 215 Mc/s
Authors: Pawsey JL , Harting E
Published: May 2011

Current theories of the mode of origin of galactic radio-frequency radiation assume the main component to be due to " synchrotron" emission by relativistic electrons in interstellar magnetic fields. Such emission is almost completely linearly polarized at the point of origin. The received radiation could, however, be substantially depolarized owing to its origin in extended regions of inhomogeneous magnetic field, or to effects associated with the rotation of the plane of polarization in ionized regions with magnetic fields along the line-of-sight. The detection of polarization is a most important observation which could substantiate the " synchrotron" emission hypothesis and provide direct evidence on magnetic fields in interstellar space.
Noise Suppression in Pulse Receivers
Authors: McLauchlan EC
Published: May 2011

In the course of measuring Southern Hemisphere meteor rates by radar methods, difficulty has been experienced in combating the effect on the meteor rate of a variable background, due to noise of both solar and man-made origin.
Facular Granule Lifetimes Determined with a Seeing?Monitored Photoheliograph
Authors: Bray RJ , Loughhead RE
Published: May 2011

A telescope designed to take exposures automatically at moments of good seeing has been used to obtain a 5! hr sequence of high quality photographs of a facular region near the east limb of the Sun. Individual facular granules are found to be much longer lived than the photospheric granules, a result which agrees with the work of ten Bruggencate (1940) and Waldmeier (1940) but disagrees with the more recent observations of Macris (1953) and of Krat and Goldberg-Rogosinskaja (1956). Fifty per cent. of the facular granules lasL for over 2 he, and 10% last for over 5 hr. In some cases, a facular granule, only 750--1500 km in diameter, occurs as an isolated bright structure, surrounded by normal photosphere and well removed from neighbouring sunspots or faculae. Apart from their greater brightness and much longer lifetimes, the facular granules differ from the photospheric granules in that they do not form awell-defined cellular pattern; these differences suggest different modes of origin
A Study of Whistling Atmospherics. II. Diffuseness
Authors: Crouchley J , Finn RJ
Published: May 2011

The diffuseness or spread, ill time, of whistlers observed at four Australian stations is discussed. It is found to be approximately twice as large for long as for short whistlers, to be independent of season and time of day, and to be lillearly related to geomagnetic latitude and whistler dispersion. The diffuseness may be accounted for by assuming that the energy travels over a range of paths in the exosphere, and estimates of this range are made (i) assuming a smooth variation of dispersion with latitude and (ii) assuming a duct-type of guiding.
The Characteristics of Persistent Sporadic Meteor Echoes
Authors: Smith JW
Published: May 2011

This paper examines the frequency distribution of the durations of nearly 8000 persistent radio echoes from sporadic meteors recorded at Adelaide during 1957. The maximum line densities in the trails formed by these meteors exceed 1013 electrons/em, corresponding to visual magnitudes < +3. As the echo duration increases, the numbers of echoes are found to fall progressively further below the numbers expected from a power-law distribution. No significant seasonal or diurnal variation in the mass distribution of the meteors examined is apparent.
The Sweep of Long Water Waves Across the Pacific Ocean
Authors: Green R
Published: May 2011

Seismic sea waves (tsunamis) are shallow water waves. The leading tsunami wave from the Chilean earthquake of May 22, 1960 at 19 hr 11 min 20 s G.M.T. arrived at Hobart in 12 hr. The tsunami was also recorded on tide gauges up the east coast of Australia and at Norfolk and Lord Howe Islands. The wave took 14 hr 04 min to reach Auckland, N .Z., but this is because of the low speed of the wave over the extensive submerged continental structure off the eastern coast of North Island. The tsunami was not recorded at Port Melbourne. From the travel-times the average depth of the Pacific Ocean between Tasmania and South America is 5500 m.
Average Forces in Electromagnetic Systems
Authors: Smith WE
Published: May 2011

The mechanical forces developed in electromagnetic systems are usually evaluated from surface integrals of the Maxwell stresses. For a large class of systems it is shown that the time average force can be expressed in terms of directly measurable circuittheory parameters. The system must be linear and loss free, but there is no restriction on the frequency of excitation.
On the Equivalence of Current Loops and Magnetic Shells
Authors: Hurst CA
Published: May 2011

A paradox in the theory of the magnetic effects of stationary currents is discussed and is shown to arise from the neglect of a singular magnetic field which is required to complete the equivalence of magnetic shells and current loops.
The Oxidation of Polycrystalline Beryllium in Carbon Dioxide
Authors: van Peer WJ
Published: May 2011

The growth and structure of beryllium oxide on polycrystalline beryllium was studied, using weight gain versus time curves, electron diffraction, and X-ray diffraction.
Orientation of Polar Auroras
Authors: Denholm JV , Bond FR
Published: May 2011

Weill (1958) has shown that the orientation of "homogeneous arc" auroras at Dumont d'Urville (see Fig. 1) exhibits definite diurnal variation, the arcs being aligned approximately on the azimuth of the Sun. Hatherton and Midwinter (1960), in considering morphology of the auroras near Scott Base and Hallett Station express the opinion that the Dumont d'Urville auroral behaviour .seems unique.
Energy Levels In 13N
Authors: McKenna VR , Baxter AM , Shute GG
Published: May 2011

The latest tabulation of energy levels in 13N (Ajzenberg-Selove and Lauritsen 1959) shows that there is a region from 8 �08 to 22�7 MeV which previously has been inaccessible to thorough investigation. Since the mirror nucleus, 130, has been thoroughly investigated and shows a well-defined level scheme in this region, it was decided to make a search for similar levels of the 13N nucleus in the excitation range 6� 5-12 . 5 MeV in this laboratory by means of elastic scattering of protons from 120.
A ? Å Birefringent Filter for Solar Research
Authors: Steel WH , Smartt RN , Giovanelli RG
Published: May 2011

A description is given of a wide�field birefringent filter having a bandwidth of t A at half� intensity, centred on HIX and tunable over �16 A. Constructional details are included.
A Study of Ionospherics at Macquarie Island
Authors: McInnes BA
Published: May 2011

Very low frequency radio emissions of natural origin, sometimes known as iono. spherics, recorded at Macquarie Island have been examined and grouped into classes. The diurnal variations of all classes show a non�uniform distribution with a peak shortly before local midday. The ionospherics appeared to fall into three groups as regards dependence on magnetic K�index. Strong correlations were discovered between values of emission frequency and K.index, for several classes of ionospherics. The roleof Cerenkov radiation in the generation of ionospherics is discussed. Suggested energy distributions are put forward to explain various classes of ionospherics. The magnetic associations and diurnal variation are explained on the basis of current geomagnetic disturbance theory. Ionospheric absorption is also considered to affect the diurnal variation. The phenomenon of" surf", as reported by Campbell and Pope, is discussed.
Slow Drift Solar Radio Bursts: Harmonic Frequency Ratios, Solar Longitude Dependence, and Frequency Drift Rates
Authors: B Wood Marion
Published: May 2011

Frequency ratios of second harmonic to fundamental bands are determined for 19 slow drift bursts. The ratios measured at the high frequency edges of the bands yield a mean value of 2� 00, whereas the mean value of the low frequency edge ratios is significantly lower than 2.
Sum?Coincidence Measurements on 154Eu
Authors: Parker AW
Published: May 2011

By examining y-rays from the radioisotope 154Eu with a fast-slow sum-coincidence spectrometer any ('I-transition to a possible 1� 82 MeV level in 154Gd has been shown to have an abundance less than 1 % of that of the ('I-transition to the neighbouring 1� 72 MeV level. The presence of a 1� 60 MeV y-ray from the 1� 72 MeV level is confirmed; the intensity of this y-ray was found to be 6�4 % of that of the 1� 28 MeV y-ray.
The Influence of Thermoelectric Effects on the Maximum Temperature in a Radially Constricted Gas Discharge Between Electrodes
Authors: Seymour PW
Published: May 2011

In an earlier paper the author provided a method for estimating the maximum temperature in a steady-state, centrally constricted, highly ionized deuterium discharge between electrodes. The analysis applied to discharges not too long, so that bremsstrahlung loss could be neglected compared to the main heat loss by conduction to the electrodes, and thermoelectric effects were not included.
Counts of Extragalactic Radio Sources
Authors: Van der Borght R
Published: May 2011

In this paper a formula is derived giving the cumulative totals of class II radio sources, to successive limits of flux density, when changes in the space� density and in the radiative properties of these sources are taken into account.
Construction of the Equivalent Electric Circuit from a Force Circuit Diagram by a Simple Graphical Method
Authors: Tschoegl NW
Published: May 2011

It has been shown elsewhere (Tschoegl1961) that mechanical problems may be formulated by constructing a force (or torque) circuit diagram setting forth the essential characteristics of the mechanical system by a set of conventional symbols. The mechanical problem may then be solved directly by the operational methods used in electric circuit analysis. Similarly, rheological problems may be formulated and solved by the aid of analogous stress circuit diagrams. The solution of mechanical and rheological problems via the equivalent electric circuit is thus completely by-passed. However, the equivalent circuit may still be needed for purposes of simulation. It is the aim of this communication to show how the equivalent electric circuit may be derived from a given force, torque, or stress circuit diagram by a simple graphical method. This is also the simplest way of setting up an equivalent circuit for a given mechanical problem since the force or torque circuit diagram is readily found by inspection.
A Phenomenological Model for Hypernuclear Binding Energies
Authors: Olley JW
Published: May 2011

The form of the dependence of the binding energy of the A-particle in hypernuclei on the mass number .A is of interest in obtaining empirical information about the hyperon-nucleon interaction. As an introductory calculation we considered the simple model in which the total A-nucleon interaction is replaced by a potential well V(r) in which the A moves and in which the only �effect of varying .A is to vary the radius but not the depth of the well. The binding energy of the A, B A' is then given by the ground state energy of a particle in this well. The aim of our calculations was to determine whether the present experimental values of B A defined a unique well sbape.
A Stability Criterion for a Radially Constricted Gas Discharge Between Electrodes
Authors: Seymour PW
Published: May 2011

The stability of a centrally constricted, highly ionized deuterium discharge between electrodes is considered. Initially, the normal mode and energy principles for the examination of plasma stability are reviewed and the results contrasted. Teller's powerful stability criterion is next obtained in a useful integral form by means of a thermodynamic analysis of interchange instability. This general geometrical result is then applied to the centrally constricted plasma between electrodes, and a sufficient stability criterion derived.
Gamma Rays from the 27Al(p, g) Reaction
Authors: Bashkin S , Ophel TR
Published: May 2011

Gamma-ray spectra and angular distributions have been measured at the 759, 766, 773, and 993 keV resonances of the reaction.
The Anomalous Thermal Expansion of Chromium
Authors: White GK
Published: May 2011

Experimental data on the linear thermal expansion between 20 and 50�C of specimens of high-purity chromium confirm the existence of an anomaly centred at 38 �C. The exact shape of this expansion anomaly between about 37 and 39�C varies markedly from sample to sample, but outside this narrow temperature interval the behaviour is more regular and seemingly related to antiferromagnetic ordering. Data on expansion are compared with other recent observations on heat capacity, magnetic susceptibility, and electrical resistivity of high-purity chromium. It is suggested that an electronic term in the expansion coefficient, observed below 20 oK to be negative, is sensitive to band structure and may be partly responsible for the change in expansion coefficient.
Cross-Relaxation Effects in a Ruby L?Band (1440 Mc/s) Maser at Low Magnetic Fields
Authors: Bogle GS , Gardner FF
Published: May 2011

The reversals of maser behaviour which occur in ruby at low fields on cooling from 80� to 4 oK are explained in terms of cross-relaxation transitions (resonant interchanges of energy between neighbouring paramagnetic ions). For an angle of 29� between the magnetic field and the crystal axis a cross-relaxation process has been demonstrated which involves groups of three ions and has a transition probability of 700� 100 per second in 0�013% ruby. The profile of the cross-relaxation resonance has a half-width of 190�30 Mcts at half-intensity, and has an approximately Gaussian shape. It should be possible to obtain useful low-field L-band maser action at 4 oK by pumping V41 with the magnetic field nearly perpendicular to the crystal axis, and also at 80 oK using a concentration ten times higher, i.e. 0�13%
Anharmonicity and the Thermal Expansion of Solids
Authors: Fletcher GC
Published: May 2011

Using many-particle perturbation theory an attempt has been made to improve the author's previous calculation of the thermal expansion of sodium chloride and to assess the effect of including anharmonic terms in the crystal potential. The results are disappointing; agreement with experiment is poor except at low and moderate temperatures. One reason for this is the poor convergence of a method based on the series expansion of the crystal potential in terms of particle displacements, 8 point further. illustrated by calculations of specific heat and compressibility.
Polarization in Nuclear Collisions with Channel Coupling
Authors: Mohr CBO , Edvi-Illes CA
Published: May 2011

The effect of the coupling between elastically and inelastically scattered waves on the polarization of particles scattered in nuclear collisions is coIisidered for the simplest case of EO excitations of the nucleus. The angular distribution of the polarization for elastic and inelastic collisions is found to be sensitive to the magnitude of the coupling parameter (the transition potential).
Gamma?Radiation Absorption Coefficients of Various Materials Allowing for Bremsstrahlung and Other Secondary Radiations
Authors: Allison JW
Published: May 2011

Existing calculations of the total absorption coefficient are generally based on the assumption that all the primary radiation energy which is converted into Comptonscattered radiation escapes from the material without significant absorption. This paper extends this basic assumption to include fluorescent and annihilation radiation and bremsstrahlung, and new values of the photoelectric, Compton, pair production, and total absorption coefficients are determined in the energy range O� 01-100 MeV for hydrogen, nitrogen, oxygen, argon, aluminium, iron, lead, air, and water. For comparison purposes revised values of the total absorption coefficient, allowing for the Compton radiation energy loss only, are also determined for these materials, using the most recent data for the component coefficients.
The Phase Speed of a Travelling Disturbance in the F Region of the Ionosphere and its Comparison with Group Velocity
Authors: Heisler LH , Whitehead JD
Published: May 2011

Three methods of measuring the phase speed of a disturbance in the F region, that is, the speed of a peak or trough in the isoionic contours, are given using ionograms records from one station. The analysis has been applied to one such disturbance whose group velocity was known to be 10 km/min. All three methods gave the phase speed to be about half of this. The theoretical explanation of this observation is discussed.
Systems for Simultaneous Image Formation with Radio Telescopes
Authors: McLean DJ , Wild JP
Published: May 2011

The large arrays of aerials often necessary for high resolution in radio astronomy are generally used to observe a brightness distribution in an area of the sky by scanning the aerial beam, point by point, across the area. In this paper we investigate the possibility of observing the complete distribution simultaneously over a given area. Two possible analogue systems capable in principle of forming such images, are described; in one, the analogue image is formed optically, in the other with ultrasonic methods. The problems and limitations of the two systems are examined and it is concluded that further technical developments are required before practical systems with useful sensitivity and resolution can be achieved.
A Catalogue of Radio Sources Between Declinations ?50° and ?80°
Authors: Mills BY , Slee OB , Hill ER
Published: May 2011

A catalogue has been prepared of the radio sources observed between declinations -50� and -80�, using the Sydney cross-type radio telescope at a wavelength of 3�5 m; a total of 219 sources is listed. This supplements the earlier catalogues for the declination ranges +10� to -20� and -20� to -50�. In addition to the positions and intensities of the sources, angular sizes of 42 of the strongest sources are given. As before, identifications with bright optical objects have been sought, and a number of possible identifications with emission nebulae and bright galaxies are listed. Because of the small area of sky covered by the present catalogue, the numbers of sources are small (compared with those in our earlier catalogues) so that the statistical analysis of their distribution has comparatively low weight.
The Galactic Radio Spectrum Down to 19·7 Mc/s
Authors: Komesaroff MM
Published: May 2011

Studies of the galactic radio spectrum have been carried out using results of a. number of surveys between 19�7 and 1390Mc/s. About 4?5� from the equator theo spectrum is non-thermal and the temperature spectral index has a constant value of 2�6�O�1.
Radio?Echo Observations of Meteors in the Antarctic
Authors: Nilsson CS , Weiss AA
Published: May 2011

Radio observations of meteors have been made at Mawson on the Antarctic continent since 1957, with a coherent pulse radar equipment operated at a frequency of 34 Mc/s. Heights and directions of reflection points are available for about 10% of the echoes, and temporal variations in these characteristics, together with the diurnal variations in the total echo rate, are analysed and discussed. All the variations observed in these characteristics agree with predictions based on a three-source model for the distribution of the radiants of sporadic meteors. This model distribution, which is symmetrical about the ecliptic, consists of a broad apex source and more concentrated sources near the Sun and antisun. The integrated intensities of the three sources are found to be approximately equal. There is evidence that the meteor echo rate is depressed at times of radio black-out, and it is suggested that periods of exceptionally high meteor activity observed during the summer months could be caused by abnormal ionospheric conditions.
Sudden Cosmic Noise Absorption at 29 Mc/s
Authors: Krishnamurthi M , Sivarama Sastry G , Seshagiri Rao T
Published: May 2011

Cosmic radio noise observations at 29 Mc/s made at Hyderabad, India (17� 26' N., 78� 27' E.), have been compared with solar flare data for the year 1958. For flares of importance 3 or 3�, there is a correlation of 84% with regard to related effects observed in the cosmic noise records. These effects are either enhanced radio emission or SCNA's. Particular study of the 9 SCNA's observed during the year and comparison with results of Bhonsle working at Ahmedabad, India (23� 02' N., 72� 38' E.), reveal that (a) even in the case of intense flares initial conditions in the terrestrial atmosphere govern the production and maintenance of an SCNA, and (b) therefore, at least at frequencies above 25 Mc/s, SCNA's cannot be used for patrolling even intense solar flares.
Some Aspects of Gyro?Splitting in the Ionosphere
Authors: Bowman GG
Published: May 2011

Ionograms for Hobart (geomagnetic latitude 52 oS.), showing x-mode propagation below the electron gyro frequency, were examined. Detailed analyses of some ionograms were made. Strong reflections for this particular propagation seem dependent on the amount of ionization, between the sporadic E level and 180 km, being reduced to a sufficiently low value. It is suggested that this can be achieved, in the sporadic E region, by the concentration of existing ionization; this concentration producing the sporadic E reflections.
Deuteron Capture by Deuterons and the Structure of 4He
Authors: Delves LM
Published: May 2011

The four-body scattering matrix describing the various scattering states of two protons and two neutrons is analysed to see what information can be gained on the structure of the bound state, 4He. It is found that an estimate can be given of the fraction of time that 'He appears as two deuterons; this estimate is� in turn used to calculate the cross sections for the process d(d, y)'He. The low energy n-3He singlet elastic scattering parameters appear to be fairly well determined by the data studied.