Showing papers by "University of Newcastle published in 1974"
TL;DR: In this article, an attempt has been made to form a qualitative correlation between the nozzle shape and the issuing jet shape, which is best achieved by a sudden, smooth contraction of the flow area from the supply line to the desired nozzle diameter.
379 citations
TL;DR: In this paper, a connection between the input-output property of passivity and a set of constraints on the state equations of the system is established, and these constraints are then interpreted in terms of the stored energy and dissipation of a passive system.
Abstract: For a broad class of nonlinear systems, a connection is established between the input-output property of passivity and a set of constraints on the state equations of the system. These constraints are then interpreted in terms of the stored energy and dissipation of a passive system. Applications are given in two problems of optimal control theory, and a generalized form of the circle criterion is also derived.
176 citations
TL;DR: Anhysteretic remanent magnetization (ARM) is used as a means of estimating lunar magnetic field palaeointensities from several Apollo 11 and 16 samples.
84 citations
TL;DR: In this article, an older series of basaltic-trachytic shield volcanoes, together with smaller nephelinitic centres, erupted and grew up on the floor of a major late-Tertiary fault-bounded depression.
Abstract: THE Neogene volcanic province of northern Tanzania is a southerly extension of the more extensive volcanic areas of Ethiopia and Kenya. It stands astride the Eastern Rift Valley and represents a complex interplay of volcanic activity and widespread Earth movements with associated faulting. A general picture is that an older series of basaltic-trachytic shield volcanoes, together with smaller nephelinitic centres, erupted and grew up on the floor of a major late-Tertiary fault-bounded depression; this earlier series includes the basaltic volcanoes of the Crater Highlands, Oldoinyo Sambu, Gelai and Kitumbeine, and the nephelinitic volcanoes Mosonik and Essimingor (Fig. 1). This volcanic area was later disrupted by a major episode of faulting that created the present-day Rift Valley depression. The main manifestation of this faulting is the major Rift Escarpment that runs from Lake Natron in the north to well south of Lake Manyara, this escarpment being the surface expression of the major Manyara–Natron Fault. The Tanzania sector of the Rift Valley is not a classic graben, as in Kenya to the north, and is bounded on its eastern side only by minor faults or down-warping. The major faulting was followed by another phase of volcanic activity, the volcanoes being dominantly nephelinitic, with carbonatite present at some centres; the major volcanoes are Hanang, Ufiome, Meni, Burko, Kerimasi and Oldoinyo Lengai together with many smaller volcanoes1. Previous geochronological studies on volcanic rocks from the Tanzania province have outlined the ages of various volcanic centres2, and also of individual flows in connection with palaeomagnetic determinations3 or anthropological studies4. The work described here has been directed at dating the faulting episodes, particularly the main phase, with a view to setting a maximum age for the onset of the later nephelinite-carbonatite magmatism, and also for the comparison with dated volcanic areas in Kenya to the north5,6. Such basic age information is also necessary for examination of the suggested temporal and spatial association of swelling, rifting and volcanicity (pluming?) with carbonatite magmatism7.
82 citations
TL;DR: Conditions are obtained for a digital filter in three or more variables to be stable, and computational techniques for checking the stability are examined.
Abstract: Conditions are obtained for a digital filter in three or more variables to be stable, and computational techniques for checking the stability are examined.
76 citations
TL;DR: In this paper, the effect of surface roughness on the friction velocity is dealt with by empirical equations and results of calculations are compared with the experimental results of other workers and a reasonable degree of agreement is shown.
74 citations
TL;DR: Suction applied to the skin causes almost immediate paranuclear vacuolization in keratinocytes but does not affect the dendritic cells, if suction is prolonged dermo‐epidermal separation occurs at a level between the basal cell membrane and basal lamina.
Abstract: SUMMARY
Suction applied to the skin causes almost immediate paranuclear vacuolization in keratinocytes but does not affect the dendritic cells. If suction is prolonged dermo-epidermal separation occurs at a level between the basal cell membrane and basal lamina.
74 citations
TL;DR: In this article, it was shown from impedance measurements that the dissolution of zinc in alkaline solutions is consistent with a two-step mechanism Z n ( O ) ⇌ e Z n( I ) a d s Z n n ( I ) → r. d. s e Z N ( I I )
63 citations
TL;DR: The extragingival lesions appear to be subject to similar problems of identification, but odontogenic lesions, as such, would seem in these cases to be a much less likely source of confusion.
63 citations
TL;DR: In this article, the analysis of sediments taken from various levels in the lightly polluted River Blyth in Northumberland showed that quite high concentrations of metals can be accumulated in sediments.
47 citations
01 Dec 1974
TL;DR: In this paper, a brushless a.c. generator is described which has a mode of operation similar to two wound-rotor induction machines connected in cascade, and a theoretical treatment is developed which takes account of magnetic saturation both in the steady state and in the transient state.
Abstract: A brushless a.c. generator is described which has a mode of operation similar to two wound-rotor induction machines connected in cascade. This cascade machine, which has previously been considered for application as a motor, has single stator and rotor windings in a conventional induction-machine frame. The machine is one of inherently high pole number. As an alternator, therefore, it is suitable for the generation of medium- to high-frequency supplies. The direct excitation current and the alternating output current flow in its one stator winding. Its cylindrical rotor iswound with an extremely simple short-circuited polyphase winding. Since no brushes, slip rings or rotating diodes are needed, the machine may be driven reliably at high speeds. A theoretical treatment is developed which takes account of magnetic saturation both in the steady state and in the transient state. Design and performance details of a prototype 400 Hz, 3000 rev/min., 3-phase machine are also included.
TL;DR: In this article, the bending experienced by a thin elastic electrode insulated on one side is used to obtain "electrocapillary" data on the gold-perchloric acid solution interface, yielding selfconsistent and numerically reasonable values of the charge on the electrode and the cationic and anionic Gibbs' surfaces excesses.
TL;DR: In this article, high-temperature creep was studied in Pb-9Sn solid solution alloy in the stress region of 3 × 10 −6 − 4 × 10−5 G using double-shear type specimens at temperatures near the melting point.
TL;DR: It is demonstrated that, in general, to achieve maximal return from an experiment, coupled design of all the experimental conditions, namely the test signal, sampling intervals and filters, should be carried out simultaneously.
Abstract: This paper discusses the problem of optimal design of experimental conditions for linear system identification. It is demonstrated that, in general, to achieve maximal return from an experiment, coupled design of all the experimental conditions, namely the test signal, sampling intervals and filters, should be carried out simultaneously. For the case of uniform sampling it is shown that joint design of the presampling filter, sampling rate and input can be carded out in the frequency domain. For the case of nonuniform sampling a sequential design procedure is developed which optimizes the information increment between samples.
TL;DR: For a given nonstationary matrix covariance with a finite-dimensionality property that is the time-varying generalization of the rational power spectrum matrix property, this paper showed how to find a linear finite-dimensional system driven by white noise with output covariance equal to the prescribed covariance.
Abstract: For a given nonstationary matrix covariance with a finite-dimensionality property that is the time-varying generalization of the rational power spectrum matrix property, we show how to find a linear finite-dimensional system driven by white noise with output covariance equal to the prescribed covariance.
TL;DR: It is argued that the statistics of the chords of the patterns are considered, leading to the histograms of the chord lengths and angles, which indicate the presence of structure in the pattern.
TL;DR: In this article, a state-space synthesis procedure for linear time-varying passive impedance matrices is given for linear-time varying matrices, using only passive components.
Abstract: A state-space synthesis procedure is given for linear timevarying passive impedance matrices. The synthesis uses only passive components.
TL;DR: In this article, it was shown that complete graphs on rm and rm + 1 vertices, r > 1, can be decomposed into stars with m edges, if and only if r is even or m is odd.
Abstract: A star is a connected graph in which every vertex but one has valency 1. This paper concerns the question of when complete graphs can be decomposed into stars, all of the same order, which have pairwise disjoint edge-sets. It is shown that the complete graphs on rm and rm + 1 vertices, r > 1, can be decomposed into stars with m edges, if and only if r is even or m is odd.
TL;DR: There was no significant difference in hypothalamic NA and corticosterone between the anosmic and sham-operated rats, however, telencephalic NA was significantly lower in anosic animals.
Abstract: Following bilateral olfactory bulb section or sham surgery, rats were subjected to a complete counterbalanced design in which appetitive and aversive conditioning were tested. Olfactory bulb section produced no appreciable effect on a food rewarded bar press response. However, a performance deficit was apparent when animals were subjected to prior fear conditioning and tested with the CS alone. On the basis of these results, rats following olfactory bulb section were subjected to prior fear conditioning and tested on avoidance learning. Anosmia produced no appreciable effect on number of avoidances, but anosmic fear conditioned rats responded more slowly than sham-operated fear conditioned rats. In order to evaluate these findings physiologically, assays were undertaken for telencephalic and hypothalamic noradranaline (NA) and plasma corticosterone. There was no significant difference in hypothalamic NA and corticosterone between the anosmic and sham-operated rats. However, telencephalic NA was significantly lower in anosmic animals.
TL;DR: In this article, an algorithm for the design of optimal detection filters in radar and communications systems, subject to inequality constraints on the maximum output sidelobe levels, is presented, and numerical results are presented.
Abstract: An algorithm is presented for the design of optimal detection filters in radar and communications systems, subject to inequality constraints on the maximum output sidelobe levels. This problem was reduced in an earlier paper (Ref. 1) to an unconstrained one in the dual space of regular Borel measures, with a nondifferentiable cost functional. Here, the dual problem is solved via steepest descent, using the directional Gateaux differential. The algorithm is shown to be convergent, and numerical results are presented.
TL;DR: In this article, the optimal fixed-lag smoothing of continuous-time signals in noise has been proposed, which is simultaneously realizable, stable in the sense of Lyapunov, and optimal.
Abstract: Novel smoother structures are introduced for the optimal fixed-lag smoothing of continuous-time signals in noise. The smoothers have the very desirable property that they are simultaneously realizable, stable in the sense of Lyapunov, and optimal. This is in contrast to those proposed to date which are either optimal and realizable but unstable, realizable and stable but suboptimal, or optimal and stable but unrealizable.
TL;DR: In this paper, a number of generalizations of singular quadratic minimization theory for the finite-time case are considered, and new stability results are derived for the infinite-time problem, and novel techniques are introduced to facilitate the derivation of singular solutions.
Abstract: A number of generalizations of singular quadratic minimization theory for the finite-time case are considered. Also new stability results are derived for the infinite time problem, and novel techniques are introduced to facilitate the derivation of singular solutions for this case. Of significance is the fact that the new results make evident the duality that exists between singular control and singular filtering problems.
TL;DR: In this paper, the design of filters for detection and estimation in radar and communications systems with inequality constraints on the maximum output sidelobe levels is considered, and a constrained optimization problem is formulated, incorporating the sidelobe constraints via a partial ordering of continuous functions.
Abstract: The design of filters for detection and estimation in radar and communications systems is considered, with inequality constraints on the maximum output sidelobe levels. A constrained optimization problem in Hilbert space is formulated, incorporating the sidelobe constraints via a partial ordering of continuous functions. Generalized versions (in Hilbert space) of the Kuhn-Tucker and duality theorems allow the reduction of this problem to an unconstrained one in the dual space of regular Borel measures.
TL;DR: The limiting form of the Kalman-Bucy filter as measurement noise tends to zero does not, in general, correspond to the optimal filter derived assuming zero measurement noise as discussed by the authors.
Abstract: The limiting form of the Kalman-Bucy filter as measurement noise tends to zero does not, in general, correspond to the optimal filter derived assuming zero measurement noise. This may be considered to be due to a difference in initial conditions.
TL;DR: In this article, the authors present an attempt to summarize simply the traffic situation in an urban area in which commuters travel to and from work using a rectangular network of roads, where positions of homes and workplaces are denoted by x and y co-ordinates.
TL;DR: Herstellung eines neuen Viologen-Indikators with hohem Redox-Potential is described in as discussed by the authors, e.g., as discussed by the authors.
Abstract: Herstellung eines neuen Viologen-Indikators mit hohem Redox-Potential.
TL;DR: In this paper, a study was conducted to determine whether logical concepts acquired in one language could be transferred to another language by pretesting in a different language and then posttesting in the previous language.
Abstract: The aim was to determine whether logical concepts acquired in one language could be transferred to another language. Subjects included 35 children bilingual in Polish and English, 31 children bilingual in German and English, and a control group of 34 Australian children, none of whom was able to conserve weight. After pretesting in one language, they were trained in the acquisition of the concept of weight using the other, then posttested in the previous language. One month later, delayed posttests were given in both languages. Results showed that the concept was acquired in either language, and there was some generalization to other concepts. Results gave some support to the Piagetian standpoint that a concept may be considered independently from the language by which it is acquired. Interference between languages was indicated in the German group in that the earlier they had learned English, the poorer was their final performance in both languages.
01 Nov 1974
TL;DR: In this paper, the authors describe situations in which adaptive identification of a linear plant is possible and apply these prototype situations to exhibit procedures for the identification of multivariable plants, where adaptive observers are also discussed.
Abstract: Situations are described in which adaptive identification of a linear plant is possible. These prototype situations are then applied to exhibit procedures for the identification of multivariable plants. Adaptive observers are also discussed.
TL;DR: Birth weights of 568 Santa Gertrudis calves by 15 sires out of 111 different dams over a 14-year period were obtained from a herd in Cuba and the overall least squares mean weight was several kg higher than previous estimates in the literature.
Abstract: Birth weights of 568 Santa Gertrudis calves by 15 sires out of 111 different dams over a 14-year period were obtained from a herd in Cuba. Year of birth, season of birth, sex of calf, sire and dam all had highly significant influences upon birth weight but there was no effect of dam age or parity. Calf inbreeding ranged from 0 to 25% and led to a decrease of 012 kg in weight for each 1% increase in inbreeding. Calves surviving to weaning or dying between birth and weaning were of similar mean weight. Calves dying at birth were some 4·53 kg above the overall average of 38·59 kg. Sire effects covered a range of some 9·85 kg in birth weight. Heritability of birth weight estimated from an intra-class correlation between paternal half-sib groups was 0·67. Repeatability estimates were of the order of 0·22 from intra-class correlation and 0-24 on the basis of regression of later on earlier records. The overall least squares mean weight of 38-59 kg was several kg higher than previous estimates in the literature.