Showing papers by "University of New South Wales published in 1969"

The Composition and Conformation of Sugars in Solution

Abstract: The conformations of the aldoses in solution, and the compositions of the equilibrium mixtures formed from aldoses after dissolution in water, have been determined by NMR spectroscopy. Calculations based on non-bonded interactions and on the anomeric effect account for the observed conformations, and allow an approximate prediction of the α:β ratio of pyranoses in equilibrium and of the extent of anhydride formation from sugars in acid solution. In certain circumstances the furanose forms are more stable than the pyranose forms.

Generalized rainfall-duration-frequency relationships

Abstract: Rainfall-duration-frequency estimates for engineering purposes are usually subject to large sampling errors and extensive generalizations of the basic data are therefore advantageous from the point of view of estimation efficiency. Relationships between high-intensity rainfall values for durations up to 2 hr and return periods up to 100 years are appropriately expressed by means of depth-duration and depth-frequency ratios. These ratios are shown to have surprisingly consistent values in such diverse places as Alaska, Hawaii, Puerto Rica, South Africa and Australia, as well as the contiguous United States, and it is suggested that a physical explanation exists for such consistencies. The data may be conveniently generalized with one of several alternative depth-duration-frequency functions which should be useful for estimates in regions of limited data.

Application of the Lifshitz Theory to the Calculation of Van der Waals Forces across Thin Lipid Films

Abstract: THEORIES of colloids1, biological cell interaction2 and thin film stability require an understanding of the role of Van der Waals dispersion forces. Calculating these attractive forces in condensed media has so far been a problem, but we now report a simple method which makes it possible to predict attractive energies and to investigate the forces in biological processes.

Monomorphisms, Epimorphisms, and Pull-Backs

Abstract: As the applications of category theory increase, we find ourselves wanting to imitate in general categories much that was at first done only in abelian categories. In particular it becomes necessary to deal with epimorphisms and monomorphisms, with various canonical factorizations of arbitrary morphisms, and with the relations of these things to such limit operations as equalizers and pull-backs.

An Experimental Investigation of the Influence of Speed and Scale on the Strain-Rate in a Zone of Intense Plastic Deformation

Abstract: Experiments are described in which an explosive quick-stop device and printed grids (0.002 in square) were used to measure the deformation (streamlines of flow) in the zone of intense shear in which the removed chip is formed in orthogonal machining. A method is given for calculating the strain-rate from the experimental streamlines and it is shown that both the maximum and mean values of the maximum shear strain-rate in this zone are directly proportional to speed (shear velocity) and inversely proportional to scale (depth of cut).

On a combinatorial generalization of 27 lines associated with a cubic surface

Abstract: Given integers 0 < λ < κ < ν, does there exist a nontrivial graph G with the following properties: G is of order ν (i.e. has ν vertices), is regular of degree κ (i.e. every vertex is adjacent to exactly κ other vertices), and every pair of vertices is adjacent to exactly λ others? Two vertices are said to be adjacent if they are connected by an edge. We call a graph with the above properties a symmetric (ν, κ, λ) graph and refer to the last of the properties as the A-condition. The complete graph of order v is a trivial example of a symmetric (ν, ν— 1, ν — 2) graph, but we are of course only interested in non-trivial constructions.

The generation of continental shelf waves

Abstract: Assuming zero divergence, the equations of forced long waves in a uniformly rotating, homogeneous ocean are reduced to a single partial differential equation for the stream function. A shelf of exponential slope between a rigid continent and a sea of uniform depth is taken as a model, and certain other assumptions are made which appear physically reasonable. Calculations made on the basis of this simplified theory are in good qualitative agreement with observations of shelf waves, indicating that these waves are generated by the stress of the longshore component of the geostrophic wind.

Zusammensetzung und Konformation von Zuckern in Lösung

Abstract: Die Konformation der Aldosen in Losung und die Zusammensetzung der Gleichgewichtsmischungen, die sich beim Losen dieser Zucker in Wasser bilden, sind NMR-spektroskopisch bestimmt worden. Berechnungen auf der Basis nichtbindender Wechselwirkungen und des anomeren Effekts gestatten eine Erklarung der beobachteten Konformationen und eine approximative Vorhersage des α/β-Verhaltnisses der Pyranosen im Gleichgewicht sowie des Ausmases der Anhydridbildung bei Zuckern in saurer Losung. In manchen Fallen sind die Furanose- bestandiger als die Pyranoseformen.

A Study of Dislocation Arrays at Spherical Indentations in LiF as a Function of Indentation Stress and Strain

Abstract: A systematic study has been made of the dislocation arrays produced by indenting (001) surfaces of LiF with steel and nylon spheres. The arrays are discussed in terms of position along a curve relating “indentation stress” to “indentation strain”, these parameters being determined by the geometry of the contact between indenter and specimen. Three stages of behaviour are distinguished: (i) elastic stage, to which the classical Hertzian contact theory is applicable; (ii) initial yield stage, to which standard yield criteria may be applied to predict the spatial location and critical resolved shear stress for initiation of dislocation motion; (iii) subsequent growth of plastic zone, in which the relative activity of the various slip systems determine the indentation behaviour. A mechanism for the initiation of dislocation flow below an indenting sphere has been proposed on theoretical grounds, and subsequently supported by experimental evidence; this mechanism differs from alternative proposals in that the dislocation sources operate within the interior of the crystal rather than at the crystal surface. An evaluation of the dislocation activation stress for LiF is thereby made, the value obtained being in reasonable agreement with results taken from conventional compression tests. The indentation stress-strain behaviour is then discussed in the light of current thought on indentation theory, and some shortcomings in present ideas are pointed out. Es wurde eine systematische Untersuchung von Versetzungsanordnungen durchgefuhrt, die durch Eindrucken von Stahl- und Nylonkugeln auf (001)-Oberflachen von LiF hervorgerufen wurden. Die Anordnungen werden durch Positionsgrosen langs einer Kurve, die die „Eindruckspannung” mit der „Eindruckdehnung” verknupfen, diskutiert. Diese Parameter sind durch die Geometrie des Kontakts zwischen Stempel und Probe bestimmt. Drei Verhaltenszustande werden unterschieden: (1) elastischer Zustand, fur den die klassische Hertzsche Theorie anwendbar ist; (2) Anfangsflieszustand, fur den Standardkriterien des Fliesens fur die Vorhersage der raumlichen Lage und der aufgelosten, kritischen Scherspannung fur das Beginnen der Versetzungswanderung angewendet werden konnen; (3) nachfolgendes Wachsen des plastischen Bereiches, in dem die relativen Aktivitaten der verschiedenen Gleitsysteme das Eindruckverhalten bestimmen. Ein Mechanismus fur den Start des Versetzungsfliesens unterhalb einer Eindruckkugel wird auf theoretischer Grundlage vorgeschlagen und durch nachfolgende experimentelle Hinweise bestarkt; dieser Mechanismus unterscheidet sich von Alternativvorschlagen dadurch, das die Versetzungs-quellen eher im Inneren des Kristalls als an der Kristalloberflache wirken. Eine Abschatzung der Versetzungsaktivierungsspannung fur LiF wird durchgefuhrt, der erhaltene Wert befindet sich in befriedigender Ubereinstimmung mit den aus konventionellen Kompressions-versuchen erhaltenen Ergebnissen. Das Eindruck-Spannungs-Dehnungsverhalten wird dann im Lichte der laufenden Vorstellungen uber die Eindrucktheorie diskutiert und einige Unzulanglichkeiten dieser Ideen werden aufgezeigt.

“I Have a Voice—Hear Me!” Findings of an Australian Study Examining the Resettlement and Integration Experience of Refugees and Migrants from the Horn of Africa in Australia

Abstract: Using the lens of “integration criteria” developed by Ager and Strang, this article presents the findings of a project documenting the resettlement and integration experiences of refugees and migrants from the Horn of Africa (HoA) in Australia. While refugees have enormous potential to integrate successfully, and many do, there are obstacles which persist. These include: trauma; separation of family members; lack of adequate on-arrival information and support; difficulties with language acquisition; lack of access to appropriate and affordable housing; lack of education support; discrimination in the work force; conflict within families; racism; and violence against women.

Subclinical renal infection and prematurity.

Abstract: 1. Evidence has been produced to confirm that clinical renal tract infection is associated with premature labour and the birth of underweight infants, the incidence in such cases being at least three times that found in non‐infected pregnant women.

The Design of Iron-Chromium-Nickel Alloys for Use at High Temperatures

Abstract: The design of iron-chromium-nickel alloys for use at high temperatures ought to be based on a knowledge of the alloy compositions that will give rise to a chromic oxide scale. For this reason, the nickel-chromium and iron-chromium-nickel alloy systems have been investigated at 1000°C under oxidizing conditions, and the isothermal sections of the nickel-chromium-oxygen and the iron-chromium-nickel-oxygen equilibrium diagrams have been determined. On the basis of these determinations, several ternary compositions are recommended as being the most suitable to form the basis of high-temperature alloys for use in oxidizing environments.

Five- and six-coordinated complexes of cobalt(II) with 2,2',2'-terpyridyl: Unusual structure and magnetism

Abstract: Cobalt(II) complexes of the type [Co(terpy)X2] (I), [Co(terpy)2]X2,nH2O (II), and [Co(terpy)2]Y2,nH2O (III), where X = Cl-, Br-, I-, NCS-, and Y = ClO4-, [BPh4]-, have been prepared and characterized by magnetic, spectroscopic, and conductance measurements. The ?mono? complexes (I) are 5-coordinated and monomeric, non-ionic in nitrobenzene, and have high-spin magnetic moments in the range 4.7-5.0 B.M. They are readily and reversibly converted into the ?bis? complexes (II) with the addition or loss of a molecule of terpyridyl: [Co(terpy)X2]+ terpy ↔ [Co(terpy)2]X2 The bis complexes (II) and (III) exhibit the characteristic features of the electronic cross-over phenomenon, their magnetic moments being strongly dependent on temperature, the anion X or Y, and water of crystallization. A model based on the 4T1-2E cross-over is set up which gives a good representation of the magnetic properties. Values of the difference between the zero-point energies of the 4T1 and 2E states are given for the various compounds. Attempts to isolate halogeno complexes of the type [Co(terpy)X]+ were unsuccessful.

Standard Energy Metabolism of Marsupials

Abstract: IN 1902, Martin1 reported that the metabolic rate of several Australian marsupials was approximately one-third of that of eutherian mammals. Since that time, this well known paper has been often quoted as showing that marsupials represent a level of physiological development intermediate between the “lower” monotremes and the “higher” eutherians, particularly in regard to temperature regulation. Recently, however, it has been shown that many marsupials can regulate their body temperatures as efficiently as most eutherians2 and therefore Martin's results have been doubted. We have made a study to see if marsupials do have a lower standard (or basal) metabolic rate than eutherians, and to find the actual level of energy metabolism of marsupials in general.

The response by microorganisms to steady state growth in controlled concentrations of oxygen and glucose. I. Candida utilis.

Abstract: Dissolved oxygen and glucose concentrations have been independently maintained at various concentrations for extended periods during growth of Candida utilis in continuous culture. Simultaneous observations of cytochrome concentration, growth rate, rates of uptake of oxygen and glucose and rates of production of CO2, ethanol and acid have been made during steady states at various levels of oxygen and glucose. There is an inverse relationship between dissolved oxygen and cytochrome and between glucose cocentration and cytochrome. Studies of the transient state following a step change from high to low dissolved oxygen show that there is a lag of about 10 hr during which there is no change in the above parameters. This is followed by rapid oscillatory changes in cytochrome content and a change to a more fermentative metabolism.

Features of trigeminal mesencephalic nucleus structure and organization. I. Light microscopy.

Abstract: The morphology and distribution of cells in the trigeminal mesencephalic nucleus were compared in newborn and adult mice, and in adult rats and cats. No gross morphological differences indicated a somatotypic subdivision of the nucleus. Changes in cell morphology in the adult mouse as compared with the newborn, are possibly related to the relatively late innervation of muscle spindles. Cell counts indicated that cell number increased not only with growth of the animal but also with increasing complexity of the jaw musculature. Analysis of the trigeminal motor root in the adult mouse showed a unimodal distribution of myelinated fibers that numericaly could not encompass both motor and mesencephalic fibers. No provision for the Y motor system appeared to be present. A substantial proportion (1:7) of cells were in soma-soma contact. The possible functional implications of these cell clusters were discussed.