Showing papers by "Northampton Community College published in 1986"
TL;DR: In this paper, the authors investigated the flow-induced surface instabilities of Kramer-type compliant surfaces by a variety of theoretical approaches and derived the critical velocity, wavenumber and stability boundaries.
Abstract: The flow-induced surface instabilities of Kramer-type compliant surfaces are investigated by a variety of theoretical approaches. This class of instability includes all those modes of instability for which the mechanism of generation involves essentially inviscid processes. The results should be applicable to all compliant surfaces that could be modelled theoretically by a thin elastic plate, with or without applied longitudinal tension, supported on a springy elastic foundation. with or without a viscous fluid substrate; material damping is also taken into account through the viscoelastic properties of the solid constituents of the coatings.The simple case of a potential main flow is studied first. The eigenmodes for this case are subjected to an energy analysis following the methods of Landahl (1962). Instabilities that grow both in space and time are then considered, and absolute and convective instabilities identified and analysed.The effects of irreversible processes on the flow-induced surface instabilities are investigated. The shear flow in the boundary layer gives rise to a fluctuating pressure component which is out of phase with the surface motion. This leads to an irreversible transfer of energy from the main stream to the compliant surface. This mechanism is studied in detail and is shown to be responsible for travelling-wave flutter. Simple results are obtained for the critical velocity, wavenumber and stability boundaries. These last are shown to be in good agreement with the results obtained by the numerical integration of the Orr–Sommerfeld equation. An analysis of the effects of a viscous fluid substrate and of material damping is then carried out. The simpler inviscid theory is shown to predict values of the maximum growth rate which are, again, in good agreement with the results obtained by the numerical integration of the Orr–Sommerfeld equation provided that the instability is fairly weak.Compliant surfaces of finite length are analysed in the limit as wave-length tends to zero. In this way the static-divergence instability is predicted. Simple formulae for critical velocity and wavenumber are derived. These are in exact agreement with the results of the simpler infinite-length theory. But, whereas a substantial level of damping is required for the instability on a surface of infinite length, static divergence grows fastest in the absence of damping on a surface of finite length.
270 citations
TL;DR: Cognitive modelling work in the area of cognitive modelling is reviewed, with particular attention paid to user models (that is, the model held by a system of a user).
Abstract: Selected current and recent work in the area of cognitive modelling is reviewed. Particular attention is paid to user models (that is, the model held by a system of a user). The relevance of this work to information retrieval is assessed and some attempts to include user models in IR systems are discussed. Implications are drawn for future work in IR.
89 citations
47 citations
TL;DR: In this article, the propriety of using the Gaines and Thomas thermodynamic formulation to evaluate activity coefficients within the exchanger phase is considered, and recent progress in the prediction of multicomponent exchange equilibria is discussed.
Abstract: Zeolites find relatively few direct applications as ion exchangers and it is perhaps for this reason that the study of their ion exchange behaviour is somewhat neglected in comparison to their other properties. Nevertheless, ion exchange is an essential part of preparative procedures for the manufacture of zeolitic sorbents and catalysts, and there is now increasing recognition of the importance of using strictly controlled conditions during ion exchange in order to avoid hydrolysis and crystal damage. Some practical points concerning ion exchange are therefore considered, and in addition two aspects of the theory of ion exchange are reviewed. Firstly, some recent discussions regarding the propriety of using the Gaines and Thomas thermodynamic formulation to evaluate activity coefficients within the exchanger phase are considered. Secondly, recent progress in the prediction of multicomponent exchange equilibria is discussed. Finally, some suggestions are made regarding possible fruitful future areas of research.
40 citations
TL;DR: The role of the occupational therapist in the treatment of chronic pain is discussed and emphasis is placed on a functional approach which maximizes the individual's control over his own pain.
Abstract: This paper discusses the role of the occupational therapist in the treatment of chronic pain. It begins with a critical evaluation of our current theoretical understanding of pain, concentrating on...
30 citations
TL;DR: The EPA's efforts to communicate with the public about the risks of ethylene dibromide (EDB), what the agency said it was doing about these risks and what information the public actually received through television and newspapers are described.
Abstract: This is a report on the Environmental Protection Agency's (EPA's) efforts to communicate with the public about the risks of ethylene dibromide (EDB), what the agency said it was doing about these risks and what information the public actually received through television and newspapers. Although special in many ways, the EDB case illustrates the problems that regulatory agencies have when they must take regulatory action and assure the public that the risks in question are being dealt with adequately. It also illustrates issues that the press faces. Above all, it illustrates the barriers to communication presented by the different perspectives of regulatory agencies and individuals and the types of information they each are most interested in.
29 citations
TL;DR: In this paper, the classical Segre, Weyr characteristic theory of the standard eigenvalue-eigenvector problem defined on A ϵ ℝn×n is extended to the case of right (left) regular pencils sF − G, F, G ϵ m×n.
Abstract: The classical Segre, Weyr characteristic theory of the standard eigenvalue-eigenvector problem defined on A ϵ ℝn×n is extended to the case of right (left) regular pencils sF — G, F, G ϵ ℝm×n. The notions of α-Toeplitz matrices and of the right (left) α. — (F, G) sequences Jα r(F,G) (Jα 1(F,G)) respectively are introduced. For right (left) regular pairs it is shown that Jα r(F,G) (Jα 1(F,G)) are piecewise arithmetic progression sequences (PAPS); the singular points of those PAPS define the possible degrees of the elementary divisors (e.d.) at α, whereas the deviations, or gaps from the arithmetic progression sequence, define the multiplicity of the corresponding degree e.d.s. The links between the algebraic notion of the Segre characteristic and the geometric notion of the Weyr characteristic are established for such families of pencils. Two different procedures for the computation of the Segre characteristic are given; the first is based on the analysis of singular points of PAPS and the second is based o...
28 citations
TL;DR: Evidence supportive of a genetic predisposition for anorexia nervosa is collated and certain speculations are proposed.
Abstract: Evidence supportive of a genetic predisposition for anorexia nervosa is collated and certain speculations are proposed. Areas of concern include consanguinity studies, the link between eating disorders and primary affective disorder, and Turner's syndrome. A diathesis-stress paradigm is offered.
26 citations
26 citations
TL;DR: The induction and persistence of DNA-strand breaks by gossypol, as well as the reduction of this effect in the presence of serum should be considered in the evaluation of the potential in vivo genotoxicity of the drug.
Abstract: Gossypol, a human antifertility agent isolated from the cotton plant, was found to induce a dose-dependent increase in the frequency of DNA-strand breaks in human leukocytes exposed to 2-40 micrograms/ml of the drug for 1 h in serum-free medium in vitro. DNA-strand breaks were studied by alkaline elution or alkaline unwinding of DNA followed by hydroxylapatite-chromatography. No decrease of gossypol-induced DNA-strand breaks was observed after post-treatment incubation times up to 24 h, whereas X-ray-induced DNA breaks disappeared within 2 h under the same incubation conditions. Cells exposed to gossypol in the presence of 10% fetal calf serum showed no or little increase of DNA breaks, suggesting that serum proteins inhibit the DNA-damaging activity of the drug. Both optical isomers of gossypol induced DNA-strand breaks. However, the effect of (-)-gossypol was only about half of that of (+)-gossypol and the racemic form. The induction and persistence of DNA-strand breaks by gossypol, as well as the reduction of this effect in the presence of serum should be considered in the evaluation of the potential in vivo genotoxicity of the drug.
24 citations
TL;DR: Differences in the timing of births are suggested, suggesting that long distance migration was associated with a postponement of the 1st or 2nd child, probably because both longer distance migration and fertility behavior are associated with other characteristics such as education.
Abstract: Relationships between migration and fertility are examined using data from the OPCS Longitudinal Study of England and Wales including linked information from the 1971 and 1981 censuses and birth registration data for the period 1971-80. The results show that the proportion moving between the 1971 Census and the 1st subsequent birth was higher among tenants than owner occupiers particularly for women in shared accommodation in 1971. The association between tenure and moving was more consistent than the relationship between moving and the husbands social class. Differences in the proportions moving between the censuses were positively associated with fertility in the same period particularly for women in potentially crowded accomodation in 1971. Moving in 1970-1971 was not associated with differences in parity progression ratios 1971-1981. There were however differences in the timing of births suggesting that long distance migration was associated with a postponement of the 1st or 2nd child probably because both longer distance migration and fertility behavior are associated with other characteristics such as education. (authors modified)
TL;DR: There are, however, important neurochemical differences in cerebral cortex, and age itself may have an important influence on the neurochemical deficits in Alzheimer's disease which are restricted in the older patients.
Abstract: Selective neuronal degeneration with concomitant changes in neurotransmitter systems are features of both normal ageing and Alzheimer's disease. There are, however, important neurochemical differences in cerebral cortex. Choline acetyltransferase declines with age in frontal cortex in contrast to the prominent change in the temporal cortex in Alzheimer's disease. The loss of somatostatin, and the recently reported reciprocal change in corticotropin-releasing factor and receptors are not seen with ageing. However, age itself may have an important influence on the neurochemical deficits in Alzheimer's disease which are restricted in the older patients. The problems of post-mortem studies in the analysis of ageing and possible approaches to this are discussed.
TL;DR: The Taguchi methods have recently become popular in the U.S.A following a realization of their importance in Japanese quality design as discussed by the authors, which is an initial attempt to extract the important ideas while drawing on the "Western" experience with response surface methodology and experimental design.
Abstract: The Taguchi methods have recently become popular in the U.S.A following a realization of their importance in Japanese quality design. This review is an initial attempt to extract the important ideas while drawing on the ‘Western’ experience with response surface methodology and experimental design.
Patent•
01 Dec 1986TL;DR: In this article, a vehicle recovery unit consisting of a first boom (9) and a second boom (11) is shown to be pivotally moveable with respect to the first boom by a piston and cylinder arrangement.
Abstract: A vehicle recovery unit is disclosed comprising a first boom (9) which is pivotally mountable on the fifth wheel (6) of a tractor unit (1), beneath which first boom (9) is pivotally mounted a second boom (11). The second boom (11) is pivotally moveable with respect to first boom (9) by a piston and cylinder arrangement (13). The second boom (11) may be secured to a vehicle to be recovered (3) by a locking pin (25) a chain under tension (26) and a load bearing member (27) so that the second boom (11) is rigidly secured to the lorry (3). When in use, the attachment of the recovery unit (2) to the lorry (3) is rigid and the combined lorry (3) and vehicle recovery unit (2) are pivotable only about the fifth wheel (6) of the tractor unit (1). The vehicle recovery unit (2) is free standing by legs (20) so that the tractor unit (1) may be detached from the recovery unit (2) and driven away to leave the recovery unit (2) free standing.
TL;DR: An ecological and rehabilitative stance for the occupational therapist in relation to the anorexic patient is developed and suggestions are made for adapting it to the occupational therapy's orientation towards practical activity.
Abstract: The first part of this paper develops an ecological and rehabilitative stance for the occupational therapist in relation to the anorexic patient. Maximizing the individual's level of psychosocial functioning is regarded as the primary aim of treatment. A model for approaching the anorexic patient is described which examines environmental factors, and the importance of assessment and follow up. The cognitive behavioral approach is discussed and suggestions are made for adapting it to the occupational therapist's orientation towards practical activity. In the second part of the paper concrete suggestions for therapy are made.
TL;DR: The reaction of 2,6-di-t-butyl-4-methylphenol with nitrogen dioxide has a first order dependence of rate on the concentration of the species N2O4 as discussed by the authors.
TL;DR: In this article, it is suggested that hydronium exchange is a general but hitherto largely unrecognised feature of all aqueous ion-exchange processes involving zeolites.
Abstract: Systematic equilibrium measurements involving analysis of solid and solution phases have been made at 25°C for the exchange of ammonium ions into the sodium forms of synthetic faujasite zeolites of SiO2/Al2O3 ratios from 1 to 2.70. Maximally exchanged ammonium forms were obtained by exhaustive ammonium treatments, with 100% removal of sodium for zeolite X but only ca. 85% for the more siliceous Y zeolites. Binary isotherms constructed from the data are strongly sigmoidal in shape, contrasting with results from earlier workers. However, under all circumstances the exchange is revealed as a ternary process involving hydronium ions; the amount of hydronium exchange is a systematic function of the SiO2/Al2O3 ratio of the framework and the extent of sodium removal, reaching 17% for an X zeolite almost devoid of sodium ions. It is suggested that hydronium exchange is a general but hitherto largely unrecognised feature of all aqueous ion-exchange processes involving zeolites.
TL;DR: A newborn infant presented with cardiac failure secondary to a peripheral cavernous haemangioma and was later diagnosed as having GM1 gangliosidosis.
TL;DR: In this paper, a model with three low-energy conformations within ca. 10 kJ mol −1 of each other is suggested, similar to theoretical gas-phase results, and a barrier to total rotation, due to steric hindrance, exists at γ ≌ 340°.
TL;DR: The crystal structure of Rubidium pentabromodistannate (II) (RbSn2Br5) was determined in this paper in the space group I 4 mcm.
TL;DR: In this article, the fundamental work on electrocatalysis for alkaline water electrolysers at The City University of New York is described and some results on the design of Teflon bonded and porous electrodes supported on nickel mesh of varying sizes.
TL;DR: The effect of prismatic spectacle corrections on ocular rotation for different object distances is determined and evaluated and the results show clear patterns in favour of spherical aberration.
01 Jan 1986
TL;DR: In West Germany, most organisations employ their quota of disabled people, although this is set at 6% as mentioned in this paper, double the level required of British employers. But German legislation in this area really more effective than British legislation, if so, why should this be?
Abstract: Government legislation, in the form of the Quota Scheme, has proved ineffective in improving the employment opportunities of disabled people in Great Britain and strenuous efforts have been made by the organisation responsible for its implementation–the Manpower Services Commission–to abolish it. In West Germany, however, most organisations employ their quota of disabled people, although this is set at 6%–double the level required of British employers. Is German legislation in this area really more effective? If so, why should this be? And what are the implications for policy in Great Britain?
TL;DR: A popular cant in education is that teachers are not so much concerned with teaching as with learning as discussed by the authors, which emerged mainly as a result of the work of new thinkers who directed attention to the importance of the learner in the learning process and who heightened an awareness of knowledge as a variable rather than as a given.
Abstract: A fashionable cant in education is that teachers are not so much concerned with teaching as with learning. This belief emerged mainly as a result of the work of new thinkers in the 1960's who directed attention to the importance of the learner in the learning process and who heightened an awareness of knowledge as a variable rather than as a given. The resulting re‐appraisal of teaching methods focussed on learning as “acts of cognition, not transferrals of information”, with the teacher as a facilitator.
TL;DR: In this article, the role of personality in effective managerial performance and current trends in management education and training are discussed. But the focus of this paper is on the use of personality questionnaires in selection, guidance and development.
Abstract: A previous article compared the OPQ and 16PF in terms of content. It commented also on the dearth of papers on the use of personality questionnaires in selection, guidance and development. This article considers (i) the general issue of the use of personality questionnaires as a source of learning in management education and training, and (ii) more specifically, the comparative acceptability to testees of the OPQ and 16PF within this context. The general issue is considered in relation to: (a) the role of personality in effective managerial performance, and (b) current trends in management education and training. Data on the comparative acceptability of the OPQ and 16PF extend that on comparative content given in the first article. While the data were collected in an education/training context, they may be indicative of relative acceptability in other occupational applications.
TL;DR: Preliminary tests show that full contrast sensitivity curves can be obtained with a small number of photographic prints and that these curves are very similar to those obtained using a carefully calibrated electronic pattern generator.
TL;DR: In this article, the anodic oxidation of a negative cadmium electrode was studied in an alkaline solution containing organic and inorganic additives, and the potential of the oxide produced per coulomb of electric current was investigated.
TL;DR: A software tool for assembly-language programming which provides an improved user interface by making use of the facilities of modern visual display units is described, Graphbug, which is designed for the Z80 microprocessor and runs under the CDOS operating system.