Showing papers by "University of Wollongong published in 1973"
01 Jan 1973
TL;DR: In this paper, it was shown that martensite nuclei are not destroyed by the transformation, and are reactivated on each cooling cycle at approximately the same temperature, which is the first reversible martensitic transformation reported for an iron-base alloy.
Abstract: Fe-Pt alloys near the composition Fe3Pt transform from fee austenite to bcc martensite at near ambient temperatures. The effect of austenite ordering in depressing theMs temperature has been reported previously, but more importantly the present work shows that ordering leads to a reversible martensitic transformation. The characteristics of this reversible transformation have been investigated by optical metallography, cinematography, and electrical resistivity measurements. It is concluded that in austenite ordered to an appropriate degree, the transformation to martensite possesses all of the characteristics of a thermoelastic martensite transformation. This transformation in ordered Fe~25 at. pct Pt alloys is the first thermoelastic martensite transformation reported for an iron-base alloy. The present experiments indicate that martensite “nuclei” are not destroyed by the transformation, and are reactivated on each cooling cycle at approximately the same temperature.
128 citations
TL;DR: For complex Hadamard matrices, Turyn as discussed by the authors showed that symmetric conference matrices cannot exist for any order larger than 1+a2 +b2 where a, b are integers.
Abstract: R. J. Turyn introduced complex Hadamard matrices and showed that if there is a complex Hadamard matrix of order c and a real Hadamard matrix of order h> > 1, then there is a real Hadamard matrix of order he. Previously, complex Hadamard matrices were only known for a few small orders and the orders for which symmetric conference matrices were known. These latter are known only to exist for orders which can be written as 1+a2 +b2 where a, b are integers. We give many constructions for new infinite classes of complex Hadamard matrices and show that they exist for orders 306,650, 870,1406,2450 and 3782: for the orders 650, 870, 2450 and 3782, a symmetric conference matrix cannot exist.
68 citations
01 Jan 1973
TL;DR: In this paper, the effect of ordering of austenitic Fe ~ 25 at. pct Pt alloys has been investigated and it was shown that the transformation crystallography remains essentially unaffected by ordering.
Abstract: Ordering of austenitic Fe ~ 25 at. pct Pt alloys results in a progressive change from a "normal" burst type transformation to a thermoelastic one. Experimental measurements are presented which show that despite marked changes in transformation behavior and kinetics, the transformation crystallography remains essentially unaffected by ordering. It is proposed that the thermoelastic transformation results from the effect of ordering in
65 citations
TL;DR: In this paper, the authors examined the relationship of the number of coal-defined and fining-upwards cycles to total thickness and mean cycle thickness using linear regression and found significant positive correlations between cycle length and thickness.
Abstract: Cyclic characteristics of a sequence of Permian coal-measure sediments have been studied using Markov chain analysis on borehole data. Fining-upwards and oscillating sequences can be distinguished, and depositional regimes are proposed to explain the observed sequences. However, there is no clearly defined relationship of sequence type to tectonosedimentary environment. The relationship of the number of coal-defined and fining-upwards cycles to total thickness and mean cycle thickness is examined using linear regression. The relationships for coal-defined and fining-upwards cycles are essentially the same. Significant positive correlations are present between the number of cycles and total thickness and significant inverse relationships are present for the number of cycles and the mean cycle thickness.
18 citations
TL;DR: In this article, a Q-mode cluster analysis has been applied to a foraminiferal fauna from Pitt Water, N.S.W. (Australia), in order to define biotopes and their geographic extent.
17 citations
14 citations
01 Jan 1973
TL;DR: Wallis as mentioned in this paper showed that if p = 1 (mod 4) is a prime power then such matrices exist for m = 1/2p(p+1)t and lOp(p + l)t for t £ 1.3.5 •.
Abstract: Recent advances in the construction of Hadamard matrices have depended on the existence of Baumert-Hall arrays and four (1,-1) matrices A, B, C, D of order m which are of Williamson type; that is, they pairwise satisfy (i) MNT = NMT, and (ii) AAT + BBT + CCT + DDT = 4mIm We show that if p = 1 (mod 4) is a prime power then such matrices exist for m = 1/2p(p+1). The matrices constructed are not circulant and need not be symmetric. This means there are Hadamard matrices of order 2p(P+1)t and 10p(p+1)t for t E {1,3,5,...,59} u {1 + 2a 10b26c ,a,b,c non-negative integers} , which is a new infinite family. Disciplines Physical Sciences and Mathematics Publication Details Jennifer Seberry Wallis, Some matrices of Williamson type, Utilitas Mathematica, 4, (1973), 147-154. This journal article is available at Research Online: http://ro.uow.edu.au/infopapers/947 SOME MATRICES OF WILLIAMSON TYPE Jennifer Seberry Wallis ABSTRACT. Recent advances in the construction of Hadamard matrices have depended on the existence of Baumert-Hall arrays and four (1.-1) matrices A. B. C. D of order m which are of Williamson type; that is. they pairwise satisfy (i) (ii) ~=~.~ AAT + BBT + CCT + DDT = 4mI m We show that if p 1 (mod 4) is a prime power then such matrices exist for m = ~(p+l). The matrices construeted are not circulant and need not be symmetric. This means there are Hadamard matrices of order 2p(P+l)t and lOp(p+l)t for t £ {1.3.5 •.•. ,59} u {I + 2a lOb26c .a,b,c non-negative integers} • which is a new infinite family. Recent advances in the construction of Hadamard matrices have depended on the existence of Baumert-Hall arrays and four (1.-1) matrices A. B. C. D of order m which are of Williamson type; that is. they pairwise satisfy (i) (ii) ~=~.~ AAT + BBT + CCT + DDT = 4mI m We show that if p 1 (mod 4) is a prime power then such matrices exist for m = ~(p+l). The matrices construeted are not circulant and need not be symmetric. This means there are Hadamard matrices of order 2p(P+l)t and lOp(p+l)t for t £ {1.3.5 •.•. ,59} u {I + 2a lOb26c .a,b,c non-negative integers} • which is a new infinite family.
13 citations
01 Aug 1973
TL;DR: In this paper, a theoretical equation for predicting velocity profiles in beds of rectangular geometry packed with equal-sized particles is presented, which requires the measurement of only one experimental variable and is attributed to porosity variations.
Abstract: A theoretical equation for predicting velocity profiles in beds of rectangular geometry packed with equal-sized particles is presented. Use of this equation to predict velocity profiles requires the measurement of only one experimental variable. Predicted and measured velocity profiles in square and rectangular packed beds using a thermistor probe were in good agreement (±5 and ±10 pct respectively). For packings containing a range of sizes it was found that the velocity was greater at the wall and at the center of the bed than it was in the intermediate regions. This behavior, which has not been previously reported, is attributed to porosity variations. Results obtained from a slice model of a copper blast furnace indicate that in these furnaces there are two separate regions of flow. One of these has two components of velocity and the other has only one. In the single component flow region the velocity may be predicted by the theoretical equation presented. The implications of the results of this investigation to nonferrous blast furnaces are also discussed.
12 citations
01 Nov 1973
TL;DR: In this paper, a theory for high frequency edge waves on a convex exponential profile, having zero depth at the coastline, is presented, and certain bounds for the frequency of the waves, in particular, the high frequency waves have a lower frequency bound which is expressed in terms of the order of the wave.
Abstract: The theory is presented for high frequency edge waves on a convex exponential profile, having zero depth at the coastline. Dispersion relations are found in terms of the longshore wave number. Certain bounds are determined for the frequency of the waves, in particular, the high frequency waves have a lower frequency bound which is expressed in terms of the order of the wave. The group velocity of the high frequency waves attains a maximum value but tends to zero at very high and very low longshore wave numbers. The group velocity is shown to be less than half the phase velocity and to always be less than a critical velocity which is a function of the shelf parameters. This critical velocity is about 26 m/s for the shelf off Sydney.
8 citations
8 citations
TL;DR: In this article, the pyrolysis of neopentylidene amino acid trimethylanilinium salts in the injector port of a gas chromatograph is described.
Abstract: Volatile derivatives of amino acids suitable for GC analysis can be obtained by the pyrolysis of neopentylidene amino acid trimethylanilinium salts in the injector port of a gas chromatograph. The new procedure offers advantages in speed and convenience over previously described GC methods.
01 Jan 1973
TL;DR: The existence of Szekeres difference sets, X and Y, of size 2f with y E Y = -y E Y, where q = 4f + 1 is a prime power, q = 5 (mod 8) and q = p2 + 4, is demonstrated in this paper.
Abstract: The existence of Szekeres difference sets, X and Y, of size 2f with y E Y = -y E Y, where q = 4f + 1 is a prime power, q = 5 (mod 8) and q = p2 + 4, is demonstrated This gives amicable Hadamard matrices of order 2(q + 1), and if 2q is also the order of a symmetric conference matrix, a regular symmetric Hadamard matrix of order 4q2 with constant diagonal Disciplines Physical Sciences and Mathematics Publication Details Jennifer Seberry Wallis, A note on amicable Hadamard matrices, Utilitas Mathematica, 3, (1973), 119-125 This journal article is available at Research Online: http://rouoweduau/infopapers/948 A NOTE ON AMICABLE HADAMARD MATRICES
TL;DR: A new polyhydroxy-1-ketosteroid, flavescin, was isolated from Marsdenia flavescens A. Cunn as discussed by the authors, and its structure was elucidated as 12- O -acetyl-3β,8β,12β,14β-20-pentahydroxy-Δ 5 - pregnene-1 one.
TL;DR: Two experiments were conducted in an attempt to establish whether 99 Ss who volunteered in sensory isolation experiments are more or less extraverted than those who do not.
Abstract: Two experiments were conducted in an attempt to establish whether 99 Ss who volunteered in sensory isolation experiments are more or less extraverted than those who do not. Volunteers were not dist...
TL;DR: Eleven known amino acids, mannitol, ergosterol, and two new steroids were isolated from an allegedly hallucinogenic Boletus and a modification of the GC-MS method used for the identification of neutral α-amino acids was reported.
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TL;DR: Wallis as discussed by the authors extended a method of Sprott [2, 3] to obtain several new families of balanced incomplete block design, which is based on the first Module Theorem of Bose [1] for pure differences.
Abstract: A balanced incomplete block design or BlBD is defined as an arrangement of v objects in b blocks, each block containing k objects all different, so that there are r blocks containing a given object and lambda blocks containing any two given objects. In this note we shall extend a method of Sprott [2, 3] to obtain several new families of BIBD's. The method is based on the first Module Theorem of Bose [1] for pure differences. We shall frequently be concerned with collections in which repeated elements are counted multiply, rather than with sets. If T1 and T2 are two such collections then T1 & T2 will denote the result of adjoining the elements of T1 to T2, with total multiplicities retained. We use the brackets, { }, to denote sets and square brackets, [ ], to denote collections of elements which may have repetitions. See [5] for results using these concepts. Disciplines Physical Sciences and Mathematics Publication Details Jennifer Seberry Wallis, A note on BIBDS, Journal of Australian Mathematical Society, 16, (1973), 257-261. This journal article is available at Research Online: http://ro.uow.edu.au/infopapers/949
TL;DR: A study was made of 84 records of suicide attempts over a 12‐month period from July, 1970, in the Port Kembla area of New South Wales, and the mean age of the men was 37‐65 years.
Abstract: A study was made of 84 records of suicide attempts over a 12‐month period from July, 1970, in the Port Kembla area of New South Wales. The majority of attempts were made by women (64), whose mean age was 32‐89 years. Seventy‐five per cent of the men and 75% of the women were married. The mean age of the men was 37‐65 years.
TL;DR: After attending a rural compensatory preschool for 5 half days a week over 1 year, Australian black and white children showed substantial gains on tests of vocabulary, auditory association, grammatic closure, and operational thinking.
Abstract: After attending a rural compensatory preschool for 5 half days a week over 1 year, Australian black and white children showed substantial gains on tests of vocabulary, auditory association, grammatic closure, and operational thinking. Tests repeated 8 months later when the children were at primary school showed marked erosion on auditory association and grammatic closure but little erosion on vocabulary or operational thinking. Scores of the black children tended to erode more than scores of the white children. The erosion was attributed to failure to correct life style deficits.
01 Jan 1973
TL;DR: Wallis et al. as mentioned in this paper discuss the recent advances in the construction of Hadamard matrices and their application in graph theory and computing, including the use of Baumert-Hall arrays and finding suitable matrices to put into these arrays.
Abstract: In the past few years exciting new discoveries have been made in constructing Hadamard matrices. These discoveries have been centred in two ideas: (i) the construction of Baumert-Hall arrays by utilizing a construction of L. R. Welch, and (ii) finding suitable matrices to put into these arrays. We discuss these results, many of which are due to Richard J. Turyn or the author. Disciplines Physical Sciences and Mathematics Publication Details Jennifer Seberry Wallis, Recent advances in the construction of Hadamard matrices, Proceedings of the Fourth Southeastern Conference on Combinatorics, Graph Theory and Computing, Congressus Numerantium, 8, (1973), 53-89. This conference paper is available at Research Online: http://ro.uow.edu.au/infopapers/953 RECENT ADVANCES IN THE CONSTRUCTION OF HADAMARD MATRICES Jennifer Seberry Wallis* University of Newcastle, N.S.W., 2308, Australia ABSTRACT. In the past few years exciting new discoveries have been made in constructing Hadamard matrices. These discoveries have been centred in two ideas: (i) the construction of Baumert-Hall arrays by utilizing a construction of L. R. Welch, and (ii) finding suitable matrices to put into these arrays. We discuss these results, many of which are due to Richard J. Turyn or the author. In the past few years exciting new discoveries have been made in constructing Hadamard matrices. These discoveries have been centred in two ideas: (i) the construction of Baumert-Hall arrays by utilizing a construction of L. R. Welch, and (ii) finding suitable matrices to put into these arrays. We discuss these results, many of which are due to Richard J. Turyn or the author. * This paper was prepared while the author was visiting the Department of Computer Science, University of Manitoba, Canada. PROC. 4TH S-E CONF. COMBINATORICS, GRAPH THEORY, AND COMPUTING, pp.53-89.
TL;DR: Apparatus capable of transmitting signals to either a vibrator or to a light, or to both vibrator and light simultaneously, is described.
Abstract: Apparatus capable of transmitting signals to either a vibrator or to a light, or to both vibrator and light simultaneously, is described. The basis for encoding vibrotactile and visual stimuli is varying intensities and durations of signal.
TL;DR: The results suggested that bisensory signalling in the cutaneous and visual channels might produce improved rates of detection or increased proficiency in learning codes.
01 Dec 1973
TL;DR: In this article, the instantaneous angular direction of the falling particle is introduced as a parameter to obtain a solution in which a nonlinear differential equation does not arise, which is an alternative to the classical brachistochrone problem.
Abstract: In the teaching of optimization methods such as in Control courses, a frequently used introductory example is the classical brachistochrone problem. The Calculus of Variations solution is usually obtained by introducing a new parameter to solve the nonlinear differential equation. This letter presents an alternative method which introduces as a parameter the instantaneous angular direction of the falling particle and obtains a solution in which a nonlinear differential equation does not arise.
Journal Article•
TL;DR: 2 groups of 10 male Ss were tested on two versions of a 6-element vibrotactile code and it was suggested that perceptually easier coding might be achieved by extending the range of intervals along the duration dimension.
Abstract: Summary.-2 groups of 10 male Ss were tested on two versions of a 6element vibrotactile code. Code A combined two intensities of signal wirh three durations. For Code B the ratio of intensities to durations was reversed. In terms of total errors there was no significant difference between the groups. However, there were significant differences in error patterns. It is suggested that perceprually easier coding might be achieved by extending the range of intervals along the duration dimension. Most research on viLrotactile learning has used a 3 X 3 matrix as the basic building block, i.e., three levels of intensity were combined with three durations, providing nine codable elements for one vibrator. Additional elements were provided by introducing further vibrators at a variety of body loci (Geldard, 1757; Diespecker, 1970). Both Geldard (1954, 1957, 1960, 1961) and Diespecker and Davidson (1771) have reported that in a 3 X 3 configuration errors come predominantly from confusions along the intensity dimension. It has been suggested that in attempting to improve (make perceptually easier) rhe coding of e!ements "the intensitive dimension is . . . the least exploicable of all the first-order dimensions" (Geldard, 1961). A greater improvement might therefore be expected by removing one level of intensity rather than one durational step. The present study tested differences in error patterns and total error scores between two configuracions, both modifications of a 3 X 3 matrix: Code A, in which the medium level of intensity was omitted (2 intensities X 3 durations = 6 elements), and Code B, in which the medium interval of duration was omitted (3 intensities X 2 durations = 6 elements). Method.-Ss were 20 high school boys aged from 14.0 yr. to 15.5 yr., from the Berkeley High School, Wollongong, New South Wales. Ten Ss were tested on Code A and 10 on Code B. The signalling unit has been described elsewhere (Diespecker & Morris, 1973). It was capable of combining three duracions of signal (0.1, 0.3, and 0.5 sec.) wirh three intensities (equivalent to 10, 15, and 20 v). The three durations were those initially described by Geldard (1957, 1961) whilst the three intensities although arbitrarily chosen have proved to be easily discriminable in past experiments (Diespecker, 1970, 1971). Ss were tested individually. Each S sat in an armchair and a vibrator was taped to the volar surface of the left wrist. Two demonstrations of each signal were given in serial order (numbered 1 to 6). This was followed by 7 test trials, each of which consisted of the G signals presented in random order.
TL;DR: Meyerhoff and A. A. Meyerhoff as discussed by the authors discuss a discussion of paper by Howard A., A.A., and Howard A.M. A., see Amer. Ass. Geol. Petrol. Bull., Vol. 56, No. 2, 1972
Abstract: Discussion of paper by Howard A. Meyerhoff and A. A. Meyerhoff, see Amer. Ass. Petrol. Geol. Bull., Vol. 56, No. 2, 1972