Showing papers by "University of Exeter published in 1981"

Phase transformations in metals and alloys

Abstract: Thermodynamics and Phase Diagrams Equilibrium Single-Component Systems Binary Solutions Equilibrium in Heterogeneous Systems Binary Phase Diagrams Influence of Interfaces on Equilibrium Ternary Equilibrium Additional Thermodynamic Relationships for Binary Solutions Computation of Phase Diagrams Kinetics of Phase Transformations Exercises References Further Readings Diffusion Atomic Mechanisms of Diffusion Interstitial Diffusion Substitutional Diffusion Atomic Mobility Tracer Diffusion in Binary Alloys Diffusion in Ternary Alloys High-Diffusivity Paths Diffusion in Multiphase Binary Systems Exercises References Further Readings Crystal Interfaces and Microstructure Interfacial Free Energy Solid=Vapor Interfaces Boundaries in Single-Phase Solids Interphase Interfaces in Solids Interface Migration Exercises References Further Readings Solidification Nucleation in Pure Metals Growth of a Pure Solid Alloy Solidification Solidification of Ingots and Castings Solidification of Fusion Welds Solidification during Quenching from the Melt Metallic Glasses Case Studies of Some Practical Castings and Welds Exercises References Further Readings Diffusional Transformations in Solids Homogeneous Nucleation in Solids Heterogeneous Nucleation Precipitate Growth5 Overall Transformation Kinetics-TTT Diagrams Precipitation in Age-Hardening Alloys Precipitation of Ferrite from Austenite Cellular Precipitation Eutectoid Transformations Massive Transformations Ordering Transformations Case Studies Exercises References Further Readings Diffusionless Transformations Characteristics of Diffusionless Transformations Martensite Crystallography Theories of Martensite Nucleation Martensite Growth1 Premartensite Phenomena Tempering of Ferrous Martensites Case Studies Exercises References Further Readings Solutions to Exercises Compiled by John C. Ion

Some practical aspects of qualitative data analysis: One way of organising the cognitive processes associated with the generation of grounded theory

Abstract: This paper has presented practical details of a tested and tried procedure which it is hoped will be of use to researchers facing the problem of analysing qualitative data, and particularly to those interested in the use of grounded theory. Behind the presentation of this procedure lies a concern that the processes of research should be as open as possible, so that neither the processes of research nor their findings are subjected to mystifications which conceal their true nature from other researchers, from the subjects of research, or from those seeking to understand the research findings when they are reported. There is, of course, an element of risk in advocating such frankness, for the researcher who lays his procedures open to public scrutiny may suddenly discover that, like the emperor, he has no clothes. But it would seem, in general, that the interests of social research can only be furthered by more discussion of the details of research procedures, particularly those which are close to the creative centre of theory building.

Support and deformability in insect wings

Abstract: Coupled investigations of insect wing movements and detailed wing morphology are in progress, and some functional principles underlying wing design are emerging. High speed cine and still photography and stroboscopy indicate that most wings undergo orderly deformation in flight. Common patterns are described and their significance discussed in the light of recent aerodynamic studies. Many aspects of wing morphology–venational features, relief, thickened areas, flexionlines and vein fractures–may be related to the control of three-dimensional shape while beating. It is usually possible to distinguish areas specialized for deformability, and for support and the limiting of deformation. Some structural adaptations for these roles are described and illustrated.

The plasma cholinesteerases: a new perspective.

Abstract: Publisher Summary This chapter presents a discussion of plasma cholinesterases. The whole field of cholinesterase polymorphism, and much of pharmacogenetics, is opened up by the clinical observation that in certain patients receiving succinylcholine, prolonged apnea developed. The best known clinical application of cholinesterase assay concerns the abnormally prolonged effect of the muscle relaxant succinylcholine that is found in a small proportion of patients. The cholinesterases are accepted as being synthesized in the liver and the assay of cholinesterase first became of interest to the clinician and to the clinical chemist as a test of liver function. Low serum cholinesterase activities are found in acute hepatitis, acute cirrhosis, and in liver metastases in those conditions where the hepatic synthesis of the protein is impaired. The synthesis of several other proteins is also reduced in such conditions, so that cholinesterase assay has been largely superseded as a test of liver function by measurements related to proteins such as albumin and prothrombin. Recommended procedures for collecting and storing plasma and serum specimens and laboratory procedures used for distinguishing the more common serum cholinesterase variants are also discussed in the chapter.

Confinement and phase transitions

Abstract: Using a density dependent quark mass to express non-perturbative interaction effects, we calculate the critical density for a phase transition between nuclear and quark matter atT=0.

Structure and Correlations in Smectic B, F and I Phases

Abstract: The question of which of the known smetic phases exhibitis long range 3 dimensional order is first discussed briefly, The major theme of the paper is the nature of the structure and correlations in SB, SF, and S1 phases. Results are presented about the temperture dependence of the interlayer stacking arrangement and the existence of strong layer undulations in crystalline SB phases and about the existence of a SB phase with very weak positional correlations between layers and short range order within the layers. The raltion between the S1 and SF structures is established for the first time: both consist of uncorrelated layers in which the molecules are tilted relative to the layer normal and have limited positional correlations within layers. Both have 3-d long range bond orientational order of the C-centered monoclinic lattices. They differ in the direction of tilt of the molecules relative to the pseudo-hexagonal packing in the plane normal to the long axes: in SF the tilet is directed towards ...

Dionysiac Drama and the Dionysiac Mysteries

Abstract: In Euripides' Bacchae Dionysos visits Thebes in disguise to establish his mysteries there. And so, given normal Euripidean practice, it is almost certain that in the lost part of his final speech Dionysos actually prescribed the establishment of his mysteries in Thebes. In the same way the Homeric Hymn to Demeter tells how the goddess came in disguise to Eleusis and finally (vv. 476–82) established her mysteries there. After coming to Eleusis she performs certain actions in the house of king Celeus, for example the drinking of the κυκeών, which have long been recognized as corresponding to ritual undergone by the initiands in the Eleusinian mysteries. It is the main thesis of this paper that just as elements of the Homeric Hymn to Demeter seem to derive from a ἱeρ⋯ς λ⋯γος of the Eleusinian mysteries, so certain elements of the Bacchae derive from a ἱeρ⋯ς λ⋯γος of the mysteries of Dionysos, and that furthermore Euripides consciously alludes to the Dionysiac mysteries for a dramatic effect dependent on the religiosity of his audience, rather as Aeschylus alludes in the Oresteia, on the principle μαθο⋯σιν αὑδ⋯, to the mysteries of Eleusis.This case will suffer from two drawbacks. Firstly there is the general scepticism about ritual patterns in drama arising as a reaction to the excesses of, for example, Murray and Cornford. This means that a far greater degree of probability seems to be required from suggestions of this kind than from the more traditional mode of speculation of, say, textual criticism. And secondly, it must be immediately and frankly admitted both that we do not know much about the mysteries of Dionysos and that most of what we do know is from the Hellenistic and Roman period. In the argument that follows recourse will sometimes be had to two assumptions. The first is to suppose a degree of continuity between the Dionysiac mysteries of the classical and later periods. This assumption is based firstly on the observable continuity of the mysteries: for example the antiquity of the Eleusinian ritual described by Plutarch, which will form an important part of my argument, is attested by Aristophanes and Plato. And it is based secondly on general considerations: conservatism is of the essence of those rituals in which a community such as a thiasos perpetuates itself by the transmission of a ritual treasured as originally taught by their god. The second assumption is to suppose, on the basis of numerous observable similarities, an essential similarity between the Dionysiac mysteries and the Eleusinian, about which we are well informed even for the classical period.

An investigation of distress and discontent in various types of nursing.

Abstract: It has been claimed that nurses in intensive therapy units are prone to high levels of distress and discontent A questionnaire was designed to assess nurses' reactions to intensive therapy work and thus provide an object check on these claims Nurses from eight intensive therapy units in England took part in the survey together with comparison groups from two renal units, a medical ward and a surgical ward High levels of job satisfaction were registered in all the intensive treatment units with very few nurses indicating distress or a wish to leave their job Some features of the work did attract criticism though, in particular the large fluctuations in work load, the level and adequacy of support, and the sparse amount of feedback given to nurses by senior staff Much the same pattern was recorded with the medical and surgical nurses, and from one of the renal units The second renal unit was known to be in a state of crisis at the time and it was predicted that a high level of discontent would be registered there This proved to be the case and was taken as conformation of the validity of the questionnaire, and also as giving insight into the psycho-social conditions which may foster distress in nurses

Mating behaviour, mycelial antagonism and the establishment of individuals in Stereum hirsutum

Abstract: Single basidiospore isolates from different fruit bodies of Stereum hirsutum always produced a morphologically distinct secondary mycelium when paired in culture. This type of mycelium was only formed in certain crosses between sibs, and the strains belonged to two incompatibility groups, indicating that the species is heterothallic. Secondary mycelia obtained from various compatible combinations of non-sibs were always strongly antagonistic when paired. Field isolates from fruit body tissue or wood were similarly antagonistic if obtained from different columns of decay in the same log or from separate localities, indicating that they represented separate heterokaryotic individuals. An unusual reaction occurred in about one-third of the incompatible pairings between sibling monospore mycelia. This took the form of a band of appressed, sparse mycelium, widest at the ends, and bounded by narrow regions of exuded droplets. These bands usually expanded unilaterally, with one of the isolates partially or totally replacing the other. In some cases this expansion stopped along a line where typical antagonism later developed. On the basis of these reactions, a simple procedure for detecting interfertility between Stereum isolates is described. This may facilitate an experimental taxonomic approach hitherto thought impossible for Stereum due to the widely held belief that members of the genus are homothallic.

Comparison among Certain Inspection Policies

Abstract: Certain continuous production processes and early warning systems must be inspected in order to detect failures that would otherwise not be apparent. An optimal inspection policy is a sequence of inspection times which minimizes the average cost per inspection cycle relative to some cost model. Under both an existing cost model, and a new cost model proposed in this paper, the computation of such policies is difficult. Three sub-optimal inspection policies are proposed, each, like the optimal policy, having decreasing times between successive inspections when the time to system failure has increasing hazard rate. Numerical comparisons are given for both cost models in the case of Weibull failure times.

Rings associated with ideals and analytic spread

Abstract: Let A be a Noether ring and let = ( a 1 ,…, a r ) be an ideal of A . There are a number of graded rings that we can associate with . In this paper we shall be concerned with the following.

Novel liquid crystal structures in cyano bi-cyclohexanes

Abstract: 2014 The structures of liquid crystal phases of three members of the series have been determined. All have nematic phases with extremely weak pseudo-layer density fluctuations and the two lowest members have bilayer smectic B type structures in which tails and cyano end groups are interdigitated. There also exist in the SB structures pronounced local modulations probably of a polar antiphase nature associated with a tendency to end-to-end ordering. In contrast cyano compounds of the type where is either cyclohexane or bi-cyclooctane have a local bilayer packing similar to that of the analogous biphenyls. J. Physique LETTRES 42 (1981) L-135 L-139 15 MARS 1981,

The chemistry of phosphinimines

Abstract: The synthesis, reactions and physical properties of phosphinimines and some related species are reviewed. Particular emphasis is placed upon recent developments in the field including their organometallic and coordination chemistry.

Conjugal Transfer of R-Plasmid R1drd-19 in Escherichia coli Below 22°C

Abstract: The conjugal transfer of R-plasmids is known to occur at temperatures above 22°C. We found that R1drd-19 is transferable below 22°C, and we discuss this finding in the context of plasmid transfer in environmental waters.

The uptake of copper by plants of mimulus guttatus differing in genotype primarily at a single major copper tolerance locus

Abstract: SUMMARY The pattern of uptake of copper by plants of Mimulus guttatus that are either homozygous tolerant, homozygous non-tolerant, or heterozygous tolerant, was compared. Tolerant plants took up more copper, particularly into the roots, and root uptake by the homozygote tolerant was greater than the heterozygote. Plants of all three genotypes took up increasing quantities of copper to their roots until day 7, but no further increase was obtained by day 11. The physiological implication of these results is discussed.

The culmination of the Main Postglacial Transgression in the Firth of Tay area, Scotland

Abstract: The morphology, stratigraphy and pollen content of deposits associated with the Main Postglacial Shoreline in two areas of carseland are described. In both, carse clays form transgressive wedges in former coastal peat mosses. The Main Postglacial Transgression culminated in both localities during the middle Flandrian; between 6679±40 and 6100±35 BP at Glencarse, near the head of the Firth, and between 7180±70 and 5890±95 BP at St Michael's Wood, in Fife. These results are discussed in the light of the probable pattern of isostatic uplift of the Main Postglacial Shoreline and with reference to some other areas in northern Britain.

Spatial development of populations of coriolus versicolor

Abstract: were similar to those found in natural populations of the fungus, with individual dikaryons present in discrete regions delimited by zones of mutual antagonism. Different dikaryons had similar growth rates and occupied approximately equal areas or volumes when inoculated simultaneously on to agar or into wood respectively. Simultaneous and sequential inoculation of sexually compatible monokaryons on to agar demonstrated that growth rate of the monokaryons and patterns of dikaryotization and nucleus migration between them are likely to be crucial determinants of the spatial distribution of dikaryons in a population. Monokaryons inoculated into logs in the field quickly became dikaryotized, and the resulting dikaryons contained diverse mating-type factors indicating the presence of a heterogeneous spore rain.

Structural correlations in smectic- F and smectic- I phases

Abstract: The x-ray diffraction pattern from aligned samples of the smectic-$I$ ($\mathrm{Sm}I$) phases of a number of compounds has been considered, with particular emphasis on TBDA (${\mathrm{C}}_{10}$${\mathrm{H}}_{21}$ PhNCHPhCHNPh${\mathrm{C}}_{10}$${\mathrm{H}}_{21}$, where Ph stands for the phenyl group) which exhibits both $\mathrm{Sm}I$ and smectic-$F$ ($\mathrm{Sm}F$) phases. It is established that both $\mathrm{Sm}I$ and $\mathrm{Sm}F$ phases are quasi-two-dimensional structures, with essentially no correlation of molecular positions between layers. They each have C-centered monoclinic lattices with long-range three-dimensional order of the lattice directions (bond orientational order) but do not have long-range positional order. The $\mathrm{Sm}F$ and $\mathrm{Sm}I$ phases differ in the direction of molecular tilt relative to the hexagonal packing of the molecular long axes: In terms of the unit cell axes, with $b$ the unique axis, $agb$ for $\mathrm{Sm}F$ and $bga$ for $\mathrm{Sm}I$. Analysis of intensity profiles from high-resolution powder measurements has led to a quantitative description of the correlation function for the molecular positions in the smectic layers. The $\mathrm{Sm}F$ phase has exponential decay of correlation with correlation lengths of order 100 \AA{}, while the (higher temperature) $\mathrm{Sm}I$ phases show algebraic decay as expected for a truly two-dimensional crystal. Current theories do not account for this result.

Annual Variation in Sterol Levels in Leaves of Taraxacum officinale Weber

Abstract: Sterol levels in dandelion (Taraxacum officinale Weber) leaves were monitored over a period of 19 months. Sitosterol was the most abundant free sterol, followed by stigmasterol, then campesterol. Cholesterol could not be detected. With the exception of stigmasterol and campesterol, esters were present in greater quantities than were free forms, with 4,4-dimethyl sterol esters being the most abundant type. Glycosides occurred only sporadically. Free 4-demethyl sterols were maximal during the winter months; levels correlated negatively with sunshine and temperature, but proportions did not alter significantly. Sitosterol ester and cycloartenol ester (but not others) showed the opposite response, with levels correlating positively with sunshine and temperature. Relative amounts of 4-demethyl sterol esters remained reasonably constant, but those of cycloartenol ester and 24-methylene cycloartanol ester varied on an annual basis and were negatively correlated with each other.

Inelastic neutron scattering by water adsorbed on silica

Abstract: Inelastic neutron scattering measurements, using a beryllium filter spectrometer, have been used to investigate the librational motions of monolayer adsorbed water on the surface of silica. The inelastic spectrum at ca. 15°K, of samples of Spherisorb S20W (mesoporous, mean pore diameter, 89 A) equilibrated with water vapor to give ca. 0.3 to 1.0 adsorbed water molecule per surface -OH group, showed librational peaks which were shifted toward frequencies lower than those of the corresponding peaks (78 and 103 meV) in bulk ice at the same temperature. The frequency shift (ca. 10–25 meV) was independent of water coverage in the range investigated, and can be shown to be consistent with a simple model involving double hydrogen bonding of an adsorbed water molecule. No change was observed in the frequency of the libration at room temperature. With microporous silica (Gasil 200, calculated pore diameter, 21 A) similar measurements at a coverage of ca. 0.35 and 1.1 adsorbed water molecules per surface -OH group show a lower frequency shift (

Teleomorphs of three aquatic hyphomycetes

Abstract: The teleomorphs of Tricladium splendens, Articulospora tetracladia and Dimorphospora foliicola are described and illustrated. They are respectively Hymenoscyphus splendens n.sp., Hymenoscyphus tetracladius n.sp. and Hymenoscyphus foliicola n.sp.