bluuebunny/crossref_metadata_2025 huggingface dataset:
Local diversity: a problem with too many solutions
Authors: Shorrocks Bryan
Published: November 2023

Population ecologists have increasingly become interested in multi-species ecology. This is clearly shown in an analysis of papers published in the Journal of Animal Ecology (JAE), between 1932 (the first volume) and 1992 (Shorrocks 1993). In the early days, population ecologists were predominantly interested in understanding the dynamics of single species systems. There were papers in JAE on multispecies communities, but they were simply descriptive. Following the golden age of the ‘bottle experiment’ (Kareiva 1989) when theoretical ideas about two-species interactions were rigorously scrutinised in the laboratory (Gause 1934; Crombie 1946; Park 1948; Utida 1953, 1957) interest in the dynamics of multi-species systems grew. This dialogue between theory and experiment laid the foundations for what was to become the dominant explanation for local biodiversity (MacArthur 1972)-resource partitioning. However, there are many levels of species diversity, and there are other possible mechanisms which may help to explain the local coexistence of species. In this chapter I will examine species diversity in a model group of insects-Drosophila.
Trophic interactions, nutrient supply, and the structure of freshwater pelagic food webs
Authors: Lacroix Gérard , Lescher-Moutoué Françoise , Pourriot Roger
Published: November 2023

Limnological studies in the first half of the century largely considered the effects of abiotic factors on aquatic communities, with those few studies on biotic interactions tending to focus on the lowest trophic levels (Persson et al. 1988). In the early 1960s, limnological studies were conducted for a large part in the context of ‘bottom-up’ tropho-dynamic concepts (Liebig’s law of limiting factors, efficiency of energy transfers between trophic levels ... ), in particular within the scope of the International Biological Program. This bottom-up view was reinforced in the late 1960s with the understanding of the major role of nutrient loading in lake eutrophication.

During this same period, some key papers (Hutchinson 1961, Hrbacek et al. 1961, Brooks and Dodson 1965) were published, stimulating for three decades an impressive number of descriptive, experimental, and theoretical studies on the respective roles of predation and competition in plankton communities. These studies led to substantial progress in the comprehension of organisms’ life histories, population dynamics, species-specific interactions, and coexistence within aquatic food webs (Kerfoot 1980, Tilman 1982, Lampert 1985, Sommer 1989).
Does climate cause the global biodiversity gradient?
Authors: Turner John R G , Lennon Jack J , Greenwood Jeremy J D
Published: November 2023

The fundamental question of biodiversity ‘why are there so many kinds of organisms?’ (Hutchinson 1959, May 1990) is easily answered in broad outline: the number of species on the planet must be governed by a dynamic equilibrium between the rate of speciation and the rate of global extinction. But a further outstanding fact about biodiversity is that it is unevenly distributed: in most groups of organisms (there are major exceptions-Hawkins 1990) there are many more species in the tropics than at higher latitudes. Diversity is very low indeed in the polar regions. Answering the question ‘why does this diversity gradient occur?’ might be an adjunct to the answer to the fundamental question, or it might contain a crucial insight into the answer to the fundamental question. It may require several different answers (Begon et al. 1986, Currie 1991). The species-energy theory, or as Turner (1992) has called it, the dynamic theory, is comparatively neglected among the many theories that have been advanced: for instance, very few front line textbooks mention it. Only since Lawton’s (1990), Currie’s (1991) and Rohde’s (1992) reviews has the theory received wide publicity, after a slow recovery from relative neglect (Brown and Gibson 1983, Wright 1983, Currie and Paquin 1987, Turner et al. 1987, Wright et al. 1994). It is still misunderstood by many, and has been widely regarded as ridiculous, trivial or obvious.
Antarctic Cheilostomatous Bryozoa
Authors: Hayward P J
Published: November 2023

Bryozoans are encrusting colonial organisms which are ubiquitous in freshwater and marine environments. As the dominant sessile organisms of the Antarctic shelf seas, they are a pivotal component of the ecosystem. This is the first identification guide to the Bryozoa and describes and illustrates all 264 species of cheilostomate Bryozoa which have been recorded from the Antarctic seas. It includes an illustrated dichotomous key to the genera, and for each genus there is a key to Antarctic species. All species are fully described, and a clear diagnosis is given for each genus, family, and superfamily.
Introduction
Authors: Hayward P J
Published: November 2023

Systematic research on the Antarctic Bryozoa has a comparatively short history. The first marine invertebrates to be described from Antarctica were a few molluscs and crustaceans collected from strand line debris on the South Shetland Islands by James Eights, surgeon and naturalist with the U.S. Antarctic Exploring Expedition (Eights 1833). It is probable that Eights encountered bryozoan colonies among the beach debris, but he neither collected nor recorded them (Winston and Hayward 1994). James Clark Ross made the first dredge hauls in Antarctic coastal waters in 1841, in the course of the Erebus and Terror Antarctic expeditions. It is known that he and Joseph Dalton Hooker made extensive collections of Antarctic marine invertebrates. Hooker prepared illustrations of many of the specimens they collected, including some collected while en route to Antarctica, and the surviving drawings, conserved at the Natural History Museum, London, apparently include a number of bryozoans (Davenport and Fogg 1989), but Ross’s collections were not worked up and were eventually destroyed. Antarctic bryozoans were not collected again until Michaelsen’s visit to South Georgia in 1892-1893.
Systematic List of Species Described
Authors: Hayward P J
Published: November 2023

Endemic species are marked with an asterisk (*). A, Presently recorded only from the Ross Sea; B, presently recorded only from the Antarctic Peninsula and/ or the Scotia Arc.
Systematic Accounts
Authors: Hayward P J
Published: November 2023

Colony consisting of uniserial, branching chains of autozooids, each comprising an adnate proximal portion, and an erect, tubular, distal portion. The adherent proximal portions give the appearance of a continuous, branching stolon, filiform or with regular dilatations, with the tubular distal portions (sometimes spatulate at the free end) regularly spaced along its length. In some instances the proximal ‘stolonic’ portions are only partly attached to the substratum, and the colony develops a diffuse, bushy form. Each autozooid comprises an attached proximal portion, a cylindrical middle region of varying length, and a distal region bearing the frontal membrane. Operculum terminal. Polypide with few tentacles, generally 12-20, and with a delicate circlet of fine teeth around base of lophophore. Embryos brooded in membranous sacs borne externally at distal end of autozooid. Small kenozooids may be intercalated between proximal portions of successive autozooids in some species; other polymorphs do not occur.
Asymmetries and developmental stability
Authors: Møller Anders Pape , Swaddle John P
Published: November 2023

In this chapter we introduce the concepts of homeostasis, canalisation, and developmental stability and how this relates to developmental stress (sections 1.2-3). We then review the ways in which developmental stability has been assessed and measured. These methods include monitoring the frequency of deviant phenotypes (phenodeviants—section 1.4.1) and measuring variation in trait size (coefficient of variation—section 1.4.2) both among and within populations. Both of these methods are limited in that it is not possible to make a priori predictions concerning the true frequency of phenodeviants or the coefficient of variation within and among populations. Therefore the populations under investigation have to be thoroughly sampled to render accurate estimates of developmental stability. These two indices also tend not to control for differences in genotype or environmental variation during development, and so may not be good estimators of developmental stability (section 1.4.3).
The reproductive biology of Australian flying-foxes (genus Pteropus)
Authors: Martin L , Kennedy J H , Little L , Luckhoff H C , O’brien G M , Pow C S T , Towers P A , Waldon A K , Wang D Y
Published: November 2023

Three Australian species of Pteropus occupying tropical to temperate habitats have similar distributions of birth-times. A fourth, P. scapulatus, overlaps the others’ ranges yet breeds six months out of phase. Captive males show annual testicular cycles which shift little between years and are unresponsive (P. scapulatus), or only sluggishly responsive (P. poliocephalus), to altered photoperiod. In the breeding-season, males increase their weight, odour and marking behaviour, copulating repeatedly with intact and ovariectomized females; out of season, copulations occur well into pregnancy. Females are not simple reflex ovulators. Lactation does not delay conception. Corpora lutea do not persist to the next pregnancy and there is no strong evidence for ovulation alternating between ovaries. Female P. poliocephalus exposed prematurely to short photoperiod do not conceive early, but females isolated until after the breeding season conceive and give birth late. With no evidence of delayed embryo implantation or development, natural late births probably reflect late conceptions. Endocrine regulation of ovulation remains enigmatic. There are no useful markers of ovarian function, peripheral progesterone levels are anomalous and endometrial growth associated with the preovulatory follicle is confined to the ipsilateral horn.
Constraint and flexibility-bats as predators, bats as prey
Authors: FENTON M Brock
Published: November 2023

Viewed as predators or as prey, bats offer excellent examples of how constraints on performance are ameliorated by behavioural flexibility. Bats hunting airborne targets often eat different things to those taking prey from surfaces. These behavioural differences determine prey species and hence energetic input per prey item. Limitations translate less directly to dietary differences when similar species are compared. Flexi bility often means exploiting concentrations of prey, such as the insects around lights, but can include different hunting behaviours and patterns of habitat use. Heterothermy, the ability to reduce body temperatures, is another facet of flexibility only available to some bats. The echolocation calls of bats function as releasers for defensive behaviour by some insects, affecting the bats’ hunting success. Some arctiid moths further affect bat hunting by producing clicking sounds as they are attacked. Some bats circumvent hearing-based insect defences by producing quiet, short echolocation calls or using other cues to find their prey. The same blend of constraints and flexibility is shown by some predators of bats. For diurnal raptors, light levels and feeding behaviour limit intake of bats. Bats emerging from roosts show behaviour patterns predicted by the selfish herd principle.
Information transfer in bats
Authors: Wilkinson Gerald S
Published: November 2023

Here I review, and present new, evidence indicating that bats gain information about their environment, i.e. the location or quality of food, roosting sites, predators or mates, from other bats. Four mechanisms-local enhancement, social facilitation, imitative learning, and intentional signalling-of acquiring or transmitting infor mation are described. Local enhancement or inad;ertent direction to a resource has been demonstrated for two situations-eavesdropping and following. Playback experiments with several species show that insectivorous bats approach echolocation calls. Non-random departures from nursery colonies have been described for several species; in Nycticeius humeralis individuals improve their foraging success by following previously successful foragers to feeding sites. Social facilitation may occur in at least one group-foraging species where per capita feeding attempts increase with group size. Imitative learning has been reported for several species learning to feed under novel situations in the laboratory, but the data are consistent with local enhancement and individual learning. Matching of echolocation call frequency in one species provides the best evidence for imitative learning, while matching of isolation calls to directive calls may simply reflect heritable ontogenetic change.
LC-UV-MS: a powerful approach for the rapid screening of metabolites in crude plant extracts
Authors: Wolfender Jean-Luc , Hostettmann Kurt
Published: November 2023

When working with medicinal plants, the main goal is to isolate and identify constituents showing interesting biological properties. Generally, bioactivity-guided fractionation of the plant extracts is performed leading to the isolation and identification of the active compounds (Hamburger and Hostettmann 1991). However, this procedure is time consuming and sometimes the active metabolites can be plant constituents already well known. Furthermore, the number of simple bioassays available in phytochemical laboratories is rather limited, giving only a partial idea of the potential activities of a crude plant extract. Thus, many interesting natural products are missed by such a limited biological screening. In order to improve this procedure, a complementary approach is needed, consisting of a chemical screening of the extracts. To perform this screening, a multidimensional approach involving hyphenated techniques such as liquid chromatography coupled with photodiode array detection (LC-UV), with mass spectrometry (LC-MS), or with tandem mass spectrometry (LC-MS/MS) have been used. Indeed LC-UV-MS gives important structural information on plant metabolites, on-line, rapidly, and with a minute amount of plant sample material. These on-line UV and MS data, together with chemotaxonomical considerations, allow an early recognition of common natural products, avoiding their time-consuming isolation. Furthermore, an efficient localization of interesting new leads can be performed.
Controlling the differentiation of mouse ES cells in vitro
Authors: Wiles Michael V , Proetzel Gabriele
Published: November 2023

In this chapter we outline the concepts and practical considerations in understanding and developing defined culture systems for the controlled in vitrodifferentiation of mouse embryonic stem (mES) cells. When looking at the history of mES-cell in vitrodifferentiation, one is struck by the level of alchemy that was introduced, and at times still is used, to obtain desired cell types. However, a fundamental difference between alchemy and science is that science is based on understanding; in designing ES-cell differentiation experiments it is essential that we have a total grasp of the question, and use reagents that are defined and reliable. In examining the differentiation of ES cells into specific, differentiated cell types we must define the system by using reagents that allow interpretation of the results and, equally important, ensure reproducibility. Ideas can thus be proposed and tested, data interpreted, and the information used by others to extend the work. It is only by progressing from alchemy to science that the full potential of ES cells can be exploited and developed coherently.
Paul P. Ewald and the building of the crystallographic community
Authors: Kamminga Harmke
Published: November 2023

Besides contributing in fundamental ways to the theory of propagation of X-rays in crystals, Paul Ewald was instrumental in consolidating the social cohesion of the international crystallographic community. This has been a diverse community since the beginnings of X-ray crystallography, comprising those concerned with the physical foundations of X-ray diffraction phenomena, those involved in developing methods of crystal structure analysis, and those engaged in crystal structure determination for the sake of its value to a range of established disciplines, from mineralogy and chemistry to metallurgy and biology. A specialized area that has close links with such a variety of fields of scientific enquiry might well have fragmented, were it not for the efforts of a number of leading figures within X-ray crystallography to stress the common problems and interests of this diverse community as a whole.
The So-Called Correction of Bragg’s Law
Authors: Ewald By P P
Published: November 2023

The traditional ‘correction of Bragg’s law’ is discussed for any value of the refractive index of the diffracting medium. The finite angular range of reflection, as given by the dynamical theory of interference, is symmetrical about the corrected Bragg glancing angle only if absorption can be neglected. In this case the centroid of the reflected intensity is given by the corrected Bragg law. When absorption has to be taken into account or when, besides the surface-reflected ray, other strong diffracted rays occur inside the crystal, the simple corrected law is not sufficient. For spectroscopic work of precision equal to that achieved for visible light a careful analysis of the incident X-ray appears necessary concerning its collimation (angular width) and polarization. Furthermore, the setting of the diffracting crystal has to be investigated in order to avoid unwanted simultaneous reflections. The ideal would be to combine a recording of the actual reflection curve with the high-precision absolute measurement of the glancing angle that serves as zero for the reflection curve. This requires novel instrumentation.
Electron Diffraction: An Introduction
Authors: Cowley J M
Published: November 2023

The demonstration of diffraction effects with electrons, by Davisson and Germer (1927) in the low-energy range and by Thomson and Reid (1927) in the higher energy range, served to confirm deBroglie's hypothesis that the electron particles could be guided by waves (see de Broglie, 1981). From this starting point the techniques of electron diffraction have developed as a basis for many types of investigation of the structure of matter. The theoretical assumption made as a basis for most of the developments is that electrons can be described in terms of waves. The wave functions, which are solutions of the Schroedinger wave equation, are effective means for describing the observable intensities.
Diffraction and Imaging in Electron Microscopy
Authors: Cowley J M
Published: November 2023

The interdependence of transmission electron microscopy (TEM), particularly for non-biological applications, and electron diffraction has become an essential component of both techniques. For the imaging of crystalline materials the contrast is strongly dependent on the diffraction conditions so that the recording of the electron diffraction pattern from the imaged area is a important part of the image interpretation. On the other hand, the electron diffraction intensity distributions are so strongly affected by size, shape, thickness and distortion of the diffracting crystals that information on these factors derived from imaging is of great significance. The availability of such information from electron microscopy has been very largely responsible for the advances in understanding of the electron diffraction processes during the last forty years in allowing detailed comparison of theoretical results and experimental observations.
Coherent Convergent Beam Diffraction
Authors: Cowley J M , da Piedade Manuel Minas
Published: November 2023

For most of the CBED applications, carried out in TEM instruments, it is appropriate to assume that the convergent beam incident on the specimen is incoherent. For each incident beam direction the diffraction effects are calculated as if for an incident plane wave; then the intensity distributions for all incident beam direction are added. No consideration is given to the possibility that interference effects may arise between electron waves generated in the sample by scattering from two different directions of incidence. This assumption can be justified by a simple calculation
J
Authors: Atkins P W
Published: November 2023

A Jablonski diagram is a schematic pprtrayal of the relative positions of the electronic and vibrational levels of a molecule without any attempt being made to show the relative geometrical locations in terms of molecular potential energy curves. Even the vibrational levels are represented only schematically. The diagrams currently used are modified versions of those introduced by A. Jablonski in 1935 in his discussion of the mechanism of °phosphorescence.
N
Authors: Atkins P W
Published: November 2023

A node is a point, line, or surface at which a wavefunction is zero and which separates regions of opposite sign of a wavefunction. The Condition that the wavefunction should change sign at a node implies that the points at infinity where ijJ approaches zero are not counted as nodes, nor are the boundaries of a well, at which the wavefunction is zero. As a general rule, the greater the number of nodes in a wavefunction, the higher its energy.
P
Authors: Atkins P W
Published: November 2023

A p orbital is an °atomic orbital with l = 1. An electron in a p orbital is called a p electron, and has an °orbital angular momentum of magnitude 2112h. Each p subshell of an atom consists of three orbitals, corresponding to the three values of m1 (+1, 0, and -1) that are permitted when l= 1. A p orbital has one angular node, which separates the wavefunction into two lobes of opposite sign (Fig. P.1). Since the node passes through the nucleus, there is zero probability of a p electron being found there. In this respect a p orbital differs sharply from an °s orbital, which can be found at the nucleus.
S
Authors: Atkins P W
Published: November 2023

An s orbital is an °atomic orbital with l = 0. An electron in an s orbital is called an s electron. There is one s orbital in each shell of an atom. All s orbitals are spherically symmetrical (with no angular nodes, Fig. S.1) but as the number of radial nodes is equal to n-1, higher shells have progressively more radial nodes (Fig. S.2). All s orbitals have non-zero amplitude at the nucleus; therefore an s electron has a non-zero probability of being found very close to the nucleus. This difference in behaviour from all other atomic orbitals (which have zero amplitude at the nucleus) is a consequence of the s orbital having zero orbital angular momentum, with the result that there is no centrifugal force acting on the electron however closely it approaches the nucleus. That an s electron can °penetrate through inner shells and approach the nucleus closely is of profound importance for the periodicity of the elements and the structure of the periodic table.
T
Authors: Atkins P W
Published: November 2023

A Tanabe-Sugano diagram shows how the energies of the °terms of an atom or ion change as the strength of a °ligand field increases. The diagrams provide a convenient way of analyzing the complicated electronic absorption spectra that are characteristic of d” complexes. The Tanabe-Sugano diagrams for d” ions in an octahedral environment are shown in Fig. T.1. The terms of the free ion are given on the left of the diagram (compare Fig. R.l). Their positions are calculated from the °Racah parameters B and C and plotted as E/B. It is usual to make a plausible assumption about the relative values of B and C (typically, C:::::::4B), for then the energies can be expressed in terms of B alone. The horizontal axis depicts increasing ligand field strength (and is expressed as /1/B, where /1 is the ligand field splitting parameter). The lines emerging from each free-atom term depict what terms they become in an octahedral environment. Thus, a 3F term of a d2 gas phase ion become the three sets of terms 3 A2, 3T1, and 3T2 in the complex.
V
Authors: Atkins P W
Published: November 2023

The valence bond theory (VB theory) was the first quantum mechanical theory of the chemical °bond when it was proposed by Walter Reitler and Fritz London in 1927, and was substantially developed by John Slater and Linus Pauling in the 1930s. It drew heavily on °Lewis’s concept of a covalent bond as a shared electron pair. The theory makes the perfect pairing approximation, in which it is supposed that structures with electrons paired in all possible ways dominate the wavefunction of the molecule. The overall wavefunction is a °superposition of all possible perfectly paired canonical structures, with those of lowest energy making the main contribution. In the context of valence bond theory, the superposition is interpreted as a °resonance of the contributing structures.
W
Authors: Atkins P W
Published: November 2023

A Walsh diagram is a °correlation diagram that portrays the variation in the orbital energies of a molecule as its shape is changed (typically as a bond angle is changed). By selecting the bond angle that results in the lowest total energy (which is approximated by the sum of the orbital energies) it is possible to predict the likely shape of the molecule from the occupation of its orbitals. It is also possible, from the changes in the populations of the orbitals, to predict how the shape will change when the molecule is electronically excited. The diagrams were first presented by A. D. Walsh in a classic series of papers that occupied a large part of one issue of the Journal of the Chemical Society in 1953. The H2A molecule will serve as an illustration of the general case.
X
Authors: Atkins P W
Published: November 2023

X-rays are electromagnetic radiation with wavelengths of the order of 100 pm and less (see °electromagnetic spectrum). A principal terrestrial source of X-rays is the bombardment of metals with high-energy electrons. X-rays are also a component of synchrotron radiation, the radiation emitted by electrons that are constrained to travel in a circular path at high speed. The radiation produced by electron bombardment consists of two components (Fig. X.l). The continuous background, which is known as Bremsstrahlung (from the German words for ‘brake’ and ‘ray’), is formed as the electrons decelerate as they plunge into the metal. Superimposed on the Bremsstrahlung are the sharp lines of the metal’s X-ray spectrum.
Z
Authors: Atkins P W
Published: November 2023

The Zeeman effect is the splitting of spectral lines into several components by a strong magnetic field. In the normal Zeeman effect, which is shown by atoms without electron spin, each line is split into three. In the more common anomalous Zeeman effect, which is shown by atoms with non-zero spin, the line structure is more complicated. The effect was first observed by the Dutch physicist Pieter Zeeman (1865-1943) in 1896.
Bragg reflection profile shape in X-ray powder diffraction patterns
Authors: Suortti P
Published: November 2023

The factors influencing the observed reflection profile shape are divided into two categories: external and internal (intrinsic) or instrument factors, and sample effects (see e.g. Chapters 7 and 8). The instrument factors include the distributions of position, direction, wavelength, and polarization of the incident beam, the transformation of these distributions at the sample due to non-ideal geometry, and recording by the analyser/detector. For a well-characterized instrument, these factors are known, and the external profile shape function can be calculated by ray-tracing. Various methods of calculation are presented. In this chapter, the sample effects are divided into those affecting the Bragg reflections and those contributing to the background. The incoherent part of the background is calculated from the known incident X-ray flux and composition of the sample, and is subtracted from the measured pattern. The remaining part, Bragg plus thermal diffuse scattering (TDS), is the observed pattern used in the Rietveld refinement. These components can be separated from each other by modelling TDS with a function which describes the fluctuations of scattering from acoustic phonons, and various possibilities are discussed below.
Some Elementary Pdfs
Authors: Shmueli Uri , Weiss George H
Published: November 2023

As has been pointed out in the previous chapter, much of the theory of crystallographic statistics is concerned with the construction of both approximate and exact pdfs for the structure factor. Before we embark on a more systematic exposition of existing approaches to the calculation of these pdfs, it is instructive to present some examples of the use of probability theory in deriving exact, although possibly not easily computable, pdfs for use in intensity statistics. We will reduce these exact results to their limiting forms as the number of atoms in the unit cell becomes large and the scattering factors are not too dissimilar. We include in this chapter a brief discussion of the analogy between problems of crystallographic statistics and some aspects of the theory of random walks.
Introduction
Authors: Brambilla Marco
Published: November 2023

Interest in h.f. waves in ionized gases was first motivated by ionospheric and astrophysical observations, and to a lesser extent by the behaviour of electrical discharges. Since about 1950, the effort to understand the properties of plasma waves has been greatly boosted by the needs for supplementary heating of fusion oriented plasmas, and has developed into an essential part of plasma physics.
Linear Wave-Particle Interactions
Authors: Brambilla Marco
Published: November 2023

Collisionless absorption of h.f. power is a remarkable property of hot plasmas, and it is of great theoretical interest to understand how it occurs. It also has practical importance, since the possibility of selective dissipation and thermalisation of h.f. waves with the appropriate frequency, phase velocity, and polarization is at the very origin of interest in huff plasma heating. We now turn to examine in more detail this aspect of plasma-wave interactions.
Collisionless Stochasticity
Authors: Brambilla Marco
Published: November 2023

To study the propagation of huff waves in a plasma it is imperative to take into account the collective response of all charged particles described by the dielectric tensor. Determining the motion of a test particle in a ‘prescribed’ huff field, however, is also a meaningful problem, and its solution is often very useful for a deeper understanding of wave-particle interactions. Thus in Section 35, by considering the motion of a charged particle in the potential of a plane electrostatic wave, we were able to clarify under which conditions collisions justify the linearization of the Vlahos equation. In this and the next two sections the single-particle point of view will be pursued further. We will show that collisions are not the only mechanism which can décor relate the motion of a charged particle with respect to a wave: the simultaneous presence of different periodicities in the force experienced by the particle leads, under appropriate conditions, to a stochastization of the motion even in the absence of collisions, and greatly amplifies the effects of collisions when they are present.
Non Linear Effects Associated with H.F. Heating
Authors: Brambilla Marco
Published: November 2023

In Section 37 we have argued that the linear theory of wave propagation has a very broad domain of applicability. It is nevertheless true that the kinetic equations governing the response of a plasma to h.f. fields are nonlinear, and the concept of linear Eigen modes is only an approximate one. Under appropriate circumstances, therefore, nonlinearities associated with the propagation of h.f. waves in plasmas can lead to new and important effects. In this chapter we will briefly indicate how such effects can be described.
The Physics of Fluid Turbulence
Authors: McComb W D
Published: November 2023

Since 1960, the study of turbulence has been enhanced by developments in areas such as laser anemometry, powerful computers, digital data processing, and theoretical methods from quantum physics. Turbulence is the archetypal, non-linear, non-equilibrium problem of statistical physics; the fundamental problems of turbulence are still unsolved, but there is growing interest in their solution. This book aims to look at fluid turbulence from the point of view of engineering science and physics to produce an integrated treatise on the nature of the physics of fluid turbulence as a universal phenomenon with a universal behaviour. As these topics are almost exclusively theoretical, the closing chapters of the book may be seen as attempting to restore a balance by dealing with some of the more practical aspects of the subject, while at the same time illustrating the amazing diversity of physical phenomena which has emerged from experimental studies of turbulence over the last few years. It is designed for those who are new to the subject and also for those familiar with the more traditional branches of the study of turbulence but not with the usages of quantum physics.
Equilibrium Gas Properties
Authors: Bird G A
Published: November 2023

The results that were obtained in §3.4 for the equilibrium distribution function f0may be summarized as follows:

The fraction of molecules with speed between c’ and c’ +de’, which make an angle between ø and ø + dø with the polar direction, and have an azimuth angle.
Collisionless Flows
Authors: Bird G A
Published: November 2023

In the absence of intermolecular collisions, collisionless flow fields are formed by the superimposition of several classes of molecule. These classes could be separate streams with different temperatures and with a :relative velocity between them, or a freestream and the reflected molecules from a surface. In most cases, these separate classes will each conform to an equilibrium or Maxwellian distribution. The superimposition may be such that the whole or only part of the distributions contribute to the region of interest in the collisionless flow.
Soil Behaviour in Earthquake Geotechnics
Authors: Ishihara Kenji
Published: November 2023

The behavior of the ground is crucial to the stability of structures during earthquake conditions. Our understanding of this behavior depends on a knowledge of soil dynamics and the deformation of soils during these catastrophic events. This book provides a comprehensive study of this subject, presenting much of the valuable material accumulated by Japanese researchers over recent years. The author covers theory, laboratory tests, and findings from the field, providing helpful guidance for civil engineers undertaking the critical task of protecting structures in vulnerable zones.
Interphase Mass Transfer
Authors: Skelland A H P
Published: November 2023

The applications of liquid-liquid extraction are increasing in diversity and this has led to a corresponding proliferation of extraction devices for industrial use. This chapter will accordingly focus on those fundamental aspects of diffusion and mass transfer that provide a unifying foundation for many of the extraction processes that may be encountered.
Axial Dispersion
Authors: Pratt H R C , Stevens G W
Published: November 2023

The treatment in the previous chapter relates specifically to pure plug flow, which in practice occurs only in extractors such as discrete-stage mixer-settlers and perforated plate columns where phase separation is virtually complete between stages. Other contactor types suffer adversely in performance from non-uniform flows in the continuous, and sometimes the dispersed phase; these are referred to collectively as axial dispersion and require the more advanced treatment described in this chapter.
Introduction
Authors: Lock G S H
Published: November 2023

At any given moment, huge amounts of thermal energy leave the earth’s surface to be carried upwards by natural convection. In this process, energy is transported by bulk motion of the fluid within which it is temporarily stored. Typically, the process is much more effective than thermal conduction which relies on diffusive molecular interactions. The latter take place at molecular velocities which hover around the velocity of sound; but molecular motion is omnidirectional and thus creates no net energy flux in any particular direction unless the temperature, and hence the sonic velocity, varies in that direction. Convective velocities, on the other hand, are frequently much less than the sonic velocity but arise in circumstances where they are essentially unidirectional; moreover, they are capable of producing large vertical energy fluxes in the presence of small vertical temperature gradients. This distinction between the microscopic and macroscopic manifestations of molecular energy flux is at the root of many natural phenomena observed in the atmosphere, the oceans, and the core of the earth.
Foreword
Authors: Taniguchi Norio
Published: November 2023

In nanotechnology the most important aim is to obtain dimensional accuracy of processed products of the order of a few nanometres. The processing accuracy is limited by machining or processing errors, which can be divided into two categories: deviational (or systematic) errors and scattering (random) errors, as shown in Fig. 0.1.
Nano-grating or one-dimensional scaling systems: diffraction gratings
Authors: Taniguchi Norio
Published: November 2023

The diffraction grating is a typical product for which nanotechnology plays a significant role in its fabrication and evaluation. It is an optical element with extremely fine parallel grooves on a flat or concave optical surface. The groove shape on a mechanically ruled grating is usually triangular, as shown in Fig. 4.l.l, and the spacing of the grooves u ranges from submicrometre to a few tens of micrometres, depending on the wavelength range in which the grating is to be used.
Introduction
Authors: LOCK G S H
Published: November 2023

For thousands of years, humankind has been aware of changes in phase but has not always understood them. In prehistoric times, primitive people watched lava solidify, ice melt, water evaporate, and rain fall; with the dawn of civilization, the extensive use of fire provided the opportunity to observe and experiment with many boiling and melting phenomena. Most significant, perhaps, was the discovery of metals whose value and wide spread use, in coinage and weaponry, led to the inevitable observation that different metals require a different ‘heat’ to melt them. But since the idea of ‘heat’ was (and remained) obscure and confused, and the scientific method itself was not widely recognized until the seventeenth century, it is not surprising that terms such as ‘melting point’ and ‘latent heat’ were unknown until modern times.
Solidification And Fluidification
Authors: LOCK G S H
Published: November 2023

Solidification is defined as the process in which a fluid is transformed into a solid; fluidification is the reverse process. Since fluids take two basic forms, there are four principal phase change processes: solid+ liquid, known as melting, and solid+ vapour, known as sublimation, are both examples of fluidification; liquid+ solid, known as freezing, and vapour+ solid, known as deposition, are the two solidification processes. The solid+ solid transformation completes the list of commonly encountered latent heat transfer processes involving solid phases.
Evaporation
Authors: LOCK G S H
Published: November 2023

In this chapter we will consider various forms of evaporation, covering both bipartitioned and dispersed systems. We may easily anticipate some of the non-dimensional groups which affect evaporation rates: for example, the ratio of sensible to latent heat, the Jakob number. To begin with, we limit ourselves to situations in which evaporation is essentially the inverse of condensation, thus permitting the use of ideas and results presented in the previous chapter. In particular, we will consider the classical Nusselt problem with condensation replaced by evaporation at the interface.
Worked Examples
Authors: LOCK G S H
Published: November 2023

Fundamentals are the core of this book. Even so, it is often helpful to illustrate their use through application. The exercises at the end of each chapter provide the student with the opportunity to test his or her understanding and at the same time gain a sense of the physical magnitudes likely to be encountered in practice. This chapter is an extension of the same learning process. It is designed as a series of fully worked examples in which theoretical ideas are developed and applied to real situations. In some circumstances, a precise computational scheme is necessary to provide an accurate prediction of temperature, heat flux, etc; in others, an order of magnitude estimate suffices. This provides a mix of situations, some quantitative but ideal and some qualitative but real.
Plasma Etching Fundamentals and Applications
Authors: Sugawara M , Stansficld Barry L , Handa S , Fujita K , Watanabe S , Tsukamoto T
Published: November 2023

The focus of this book is the remarkable advances in understanding of low pressure RF (radio frequency) glow discharges. A basic analytical theory and plasma physics are explained. Plasma diagnostics are also covered before the practicalities of etcher use are explored.
Properties Of The Various Metals, Impurity Content, And Refining
Authors: Engh T Abel , Simensen Christian J , Wijk Olle
Published: November 2023

Partly as a background and a framework for the other chapters a very brief and introductory presentation is given in this chapter of the various metals, their physical properties, how they are extracted, and how this affects the content of impurities and inclusions. The aim has certainly not been to produce a handbook but rather to outline the problems, point out properties of interest to workers in refining, and to encourage a general systematic approach that applies to any metal. The review is based on the periodic table of the elements (see Table 2.13). Metals are included because of their commercial importance or, as in the case of the alkali metals, because they can be used to illustrate some important problems or principles in refining. When an element is not dealt with, it is hoped that the position in the periodic table will give an indication of the impurities and problems that will be encountered in purification.
Dispersive non-linear pulse phenomena in guiding circuits
Authors: Shvartsburg A B
Published: November 2023

The physical basis non-linear regimes of signal transmission by means of guided systems is the overlapping of some fields of non-linear optics, electrodynamics of bounded systems, and communication theory. The non-linear optical effects point out the physical mechanism of rebuilding of amplitude and spectral envelopes, phase, and the polarization of powerful wave pulses. The mode structure of travelling waves, typical of guided systems, determines the energetic characteristics and spatial scales of such rebuilding. The application of non-linear processes to the coding, transmission and receiving of signals is discussed in the framework of communication theory.
Dimensional Analysis And Reactor Design
Authors: Guthrie R I L
Published: November 2023

It becomes apparent at an early stage in one’s career as an engineer that purely theoretical analyses rarely produce completely correct solutions to the problems set by real systems. For example, the detailed perf9rmance of many metallurgical and chemical reactors of the type mentioned in Chapter 1 would defy analytical solution. While it may be desirable to have a complete mathematical solution describing gas, steel and slag flows in a basic oxygen furnace, together with associated chemical reactions, the task would be difficult for even the most sophisticated of mathematical models. The problem is certainly not amenable to analytical solution. It is clear that alternative approaches are needed in the analysis of such problems.
Geometric Computation for Machine Vision
Authors: Kanatani Kenichi
Published: November 2023

Machine vision is the study of how to build intelligent machines which can understand the environment by vision. Among many existing books on this subject, this book is unique in that the entire volume is devoted to computational problems, which most books do not deal with. One of the main subjects of this book is the mathematics underlying all vision problems - projective geometry, in particular. Since projective geometry has been developed by mathematicians without any regard to machine vision applications, our first attempt is to `tune' it into the form applicable to machine vision problems. The resulting formulation is termed computational projective geometry and applied to 3-D shape analysis, camera calibration, road scene analysis, 3-D motion analysis, optical flow analysis, and conic image analysis. A salient characteristic of machine vision problems is that data are not necessarily accurate. Hence, computational procedures defined by using exact relationships may break down if blindly applied to inaccurate data. In this book, special emphasis is put on robustness, which means that the computed result is not only exact when the data are accurate but also is expected to give a good approximation in the prescence of noise. The analysis of how the computation is affected by the inaccuracy of the data is also crucial. Statistical analysis of computations based on image data is also one of the main subjects of this book.
Sensorless Vector and Direct Torque Control
Authors: Vas Peter
Published: November 2023

This is the first comprehensive book on sensor less high performance a.c. drives. It is essential reading for anyone interested in acquiring a solid background on sensor less torque-controlled drives. It presents a detailed and unified treatment of sensor less vector-controlled and direct-torque controlled drive systems. It also discusses the applications of artificial intelligence to drives. Where possible, space vector theory is used and emphasis is laid on detailed mathematical and physical analysis. Sensorless drive schemes for different types of permanent magnet synchronous motors, synchronous reluctance motors, and induction motors are also presented. These include more than twenty vector drives e.g. five types of MRAS-based vector drives, and eleven types of direct-torque-controlled (DTC) drives, e.g. the ABB DTC drive. However, torque-controlled switched reluctance motor drives are also discussed due to their emerging importance. The book also covers various drive applications using artificial intelligence (fuzzy logic, neural networks, fuzzy-neural networks) and AI-based modelling of electrical machines. Finally, self-commissioning techniques are also discussed. This is a comprehensive thoroughly up-to-date, and self-contained book suitable for students at various levels, teachers, and industrial readership. Peter Vas is a Professor at the Department of Engineering at the University of Aberdeen, UK, where he is also the Head of the Intelligent Motion Control Group. His previous books published by Oxford University Press are extensively used worldwide.
Introduction to torque-controlled drives
Authors: Vas Peter
Published: November 2023

In the past, d.c. motors were used extensively in areas where variable-speed operation was required, since their flux and torque could be controlled easily by the field and armature current. In particular, the separately excited d.c. motor has been used mainly for applications where there was a requirement of fast response and four-quadrant operation with high performance near zero speed. However, d.c. motors have certain disadvantages, which are due to the existence of the commutator and the brushes. That is, they require periodic maintenance; they cannot be used in explosive or corrosive environments and they have limited commutator capability under high-speed, high-voltage operational conditions. These problems can be overcome by the application of alternating-current motors, which can have simple and rugged structure, high maintainability and economy; they are also robust and immune to heavy overloading. Their small dimension compared with d.c. motors allows a.c. motors to be designed with substantially higher output ratings for low weight and low rotating mass.