bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Cont Act Processes
Authors: LOCK G S H
Published: November 2023

It will be recalled from Chapter 1 that there are many situations in which latent heat transfer may occur in the absence of a separating wall. Spray condensers, combustion chambers, and crystallizers are representative industrial examples. In an environmental context, pollution and water conservation have stimulated interest in such devices as the cooling tower and the cooling pond. Even wider is the traditional interest in latent heat found in the environmental disciplines of glaciology, meteorology, and oceanography. In any of these contexts the situation is essentially the same: two media, one hotter than the other, lie in intimate contact with each other. Phase change at the boundary between the media is then no longer influenced by an intervening wall with its characteristic ability to promote heterogeneous nucleation. In general, the media are not pure components, as when sea water freezes or water vapour condenses from the atmosphere. In certain circumstances, therefore, the exchange of latent heat produces concentration gradients at the common interface. The absence of an impermeable wall then implies diffusive mass transfer through and between the media.
RF discharges
Authors: Sugawara M
Published: November 2023

The RF discharge has a different behaviour to the DC discharge in the sense that at the applied frequency of 13.56 MHz, ions hardly respond to the time variation of the applied electric field, so that regions of the ion space-charge layer are formed in front of both electrodes.
The Effect Of Dissolved Elements And Inclusions On The Properties Of Metal Products
Authors: Simensen Christian J
Published: November 2023

Metals have been in service for mankind since the early days of civilization. Tools were made from meteorites as far back as 10 000 BC, and copper was in use by the Sumerians in around 4500 BC. The use of light metals is of a much more recent date. The mass production of aluminium started in 1886 with the invention of the Hall-Heroult process, while magnesium was mass-produced only after World War I. The range of products is vast. Metals are in use in high technology environments in satellites and aircraft and in common products such as kitchenware, refrigerators, and vacuum cleaners. All these products have one thing in common: certain impurities are prohibited as they ruin the metal quality, while other elements are added in order to meet specific requirements. Some of the major effects of impurities on product quality are outlined in this chapter in order to emphasize the necessity of chemical control and refining of the solvent metal and additions.
Removal Of Dissolved Impurity Elements From Molten Metals
Authors: Engh T Abel , Simensen Christian J , Wijk Olle
Published: November 2023

Impurities are already present in the ores and raw materials used in the extractive metallurgical processes. Impurities and inclusions are also introduced from refractories and atmosphere during the production of the metal and even in the refining processes. Thus oxygen, hydrogen, nitrogen, and carbon often enter the molten metal and affect the mechanical properties of the cast metal.For many extractive processes it is not practical and economic to try to protect the melt from the environment. Instead, the impurities are removed in the final refining operations. Basically in the refining stages we reverse the transfer of impurities. For instance, hydrogen and nitrogen are eliminated by gas purging and vacuum treatment.
Solidification And Refining
Authors: Engh T Abel , Simensen Christian J , Wijk Olle
Published: November 2023

A worker in refining metallurgy is not only concerned with attaining the specified mean composition of his melt; he must also take into consideration what happens during solidification. Problems with the accumulation of impurities may force him to reduce impurities down to very low levels In the solidification of an alloy over a temperature range, there is a variation of solute in the growing solid dendrite from that first deposited until the transformation into solid of the final liquid. Within a scale determined by the dendrite arms spacing, this variation of composition is termed micro segregation. To describe segregation in this case one very often assumes that there is no diffusion in the solid. Then the assumption that there is complete mixing in the inter dendritic liquid and no mass flow in or out of the volume element leads to a simple conservation equation for the solute.
Refining And Recycling Metallurgy In The Future
Authors: Engh T Abel , Simensen Christian J , Wijk Olle
Published: November 2023

Refining metallurgy deals with the treatment of the extracted or recycled metal by purification and alloying. Traditionally, the refining metallurgist has had a good knowledge of extractive metallurgy and of the impurities present in the raw metal. Often there are problems with oxidation or evaporation of alloy additions that result in a low or variable yield. These problems must be solved and taken into account in the melt treatment.
Basic Principles Of Hot-Wire Anemometry
Authors: Bruun H H
Published: November 2023

This chapter describes the basic principles, which apply to most hot wire anemometer (HWA) applications. The topics discussed include heat transfer, the sensitivity coefficients of the hot-wire signal, the frequency response of a sensor operated in the Constant-Current (CC) and Constant Temperature (C7) modes, and the spatial resolution. These aspects con tribute significantly to the performance of a HWA system. To give an adequate description of these topics the presentation is somewhat mathematical, and it is recommended that readers who are new to HWA read Chapter 3, Introduction to Velocity Measurements, first.
Three-Component Velocity Measurements
Authors: Bruun H H
Published: November 2023

If only the mean-velocity components and the Reynolds stresses are required, multiposition techniques involving single normal (SN), single yawed (SY), or X probes can be applied. Related techniques and solution procedures for one-component, two-component and three-component mean velocity flow fields are described in Sections 6.1 and 6.2. For more detailed flow studies, simultaneous measurements of three velo city components of the velocity vector at a point can be carried out with a hot-wire probe containing three (or four) sensors. The techniques dis cussed in section 6.3 can be applied provided that the velocity vector remains within the approach octant defined by the three sensors.
Time-Series Analysis
Authors: Bruun H H
Published: November 2023

The output from a hot-wire anemometer (HWA) sensor will in general be a time-varying signal representing typically, a velocity component. Other measurable quantities include the vorticity, the temperature, the concentration in gas mixtures, etc. In a turbulent flow, the anemometer signal will be of a random nature, and a statistical description of the content of the signal is therefore necessary. In the early statistical turbulent-flow studies, much emphasis was placed on spectral analysis and statistics based on statistically independent samples. However, the development of computational fluid dynamics (CFD) has caused a change of emphasis in much of the current experimental HWA work. As described in Chapter 1, the validation of CFD codes requires accurate measurements of the mean-velocity components and Reynolds stresses, and the measurement of these quantities and the related error estimates will therefore be described in some detail. Most contemporary experimental work is carried out using digital computers, and the corresponding evaluation procedures and problems are also highlighted in this chapter, which reflects the accumulated expertise in this field. Noticeable contributions include those by Bendat and Piersol (1966, 1971, 1986), Jenkins and Watts (1968), Lumley (1970), Tennekes and Lumley (1972), Van Atta (1974), Rabiner and Gold (1975), George eta/. (1978), Williams (1981), Castro (1989), and Tropea (1991). The author has particulary found presentations by Bendat and Piersol (1971, 1986) both clear and useful.
An Introduction To Transport Phenomena And Properties In Metallurgical Operations
Authors: Guthrie R I L
Published: November 2023

In today’s world of high-level competition, of technical competence, and of relatively low bulk-transportation costs, any company involved in chemical or metallurgical manufacturing must make maximum use of efficient processing operations. For engineers and researchers engaged in the development and operation of such practices, a knowledge of thermodynamics and process kinetics is essential.
Computational Projective Geometry, 1
Authors: Kanatani Kenichi
Published: November 2023

This chapter presents a computational formalism that deals with collinearity of points and concurrency of lines on a 2-D plane from the standpoint of projective geometry. The image plane is regarded as a 2-D projective space, and points and lines are represented by unit vectors consisting of homogeneous coordinates, which we call N-vectors. Fundamental notions of projective geometry such as collineations, correlations, polarities, poles, polars, and conics are all reformulated as computational processes in terms of N-vectors. The camera rotation transformation, which will later play an important role, is defined as a special collineation resulting from rotation of the camera. The cross ratio is expressed in terms of N-vectors, and its invariance is proved with respect to general projective transformations, which include perspective projection. Then, one and two-dimensional projective coordinates based on cross ratios are introduced, and typical applications that take advantage of the perspective invariance of cross ratios are presented. Implications of harmonic ranges are also studied with regard to 3-D interpretation of scenes.
Translational Motion and Stereo
Authors: Kanatani Kenichi
Published: November 2023

When observing a projection of rigidly moving space points, can we compute their 3-D structure and 3-D motion? This problem is known as shape from motion or structure from motion. In this chapter, we study translational motions by applying the concepts and formalisms developed in Chapters 2 and 3. In analysing 3-D translational motions, focuses of expansion plays the same role as vanishing points of parallel space lines. Introducing N-velocity, we show that the 3-D shape of a translating object can be reconstructed up to scale from two consecutive images. Displacing the camera also produces effective translational motion of objects relative to the camera, and the resulting image motion of points and lines reveals their 3-D geometries. This fact is known as motion parallax. We present a computational procedure for computing the 3-D geometry from a known camera displacement. To do this, we represent a space point by its N-vector and depth, and a space line by its N-vector and P-vector. Analysis of stereo is equivalent to motion parallax analysis: the trajectories of feature points and the focus of expansion correspond to the epipolars and the epipole, respectively. The depth map can be expressed in terms of the disparity map. Stereo with different camera orientations, or converging stereo, can also be formulated as general motion parallax.
Analysis of 3-D Rigid Motion
Authors: Kanatani Kenichi
Published: November 2023

In this chapter, we study general 3-D rigid motion with special emphasis on the robustness of computation. The uniqueness of the solution is also an important issue. First, we study 3-D motion of a planar surface, which induces a collineation on the image plane. A noise robust least-squares scheme is presented for determining the collineation from both point correspondence and line correspondence. Then, we show that the 3-D surface position and motion can be computed analytically. For an object of general shape, the analysis is divided into two types: point correspondence analysis and line correspondence analysis. For point correspondence analysis, the problem is first formulated as nonlinear least-squares optimization, and then a noise robust analytical procedure is derived from the epipolar equation expressed in terms of the essential matrix. Line correspondence analysis is also formulated as nonlinear least-squares optimization, and then a noise robust analytical procedure is derived from the motion parallax equations expressed in terms of the essential tensor. In both cases, the "optimal resolution" introduced in Chapter 5 plays an essential role. Finally, we study ambiguities of 3-D interpretation. For point correspondence, multiple interpretations arise if and only if all feature points are on a special type of quadric surface called the critical surface. The condition for the critical surface to degenerate into two planar surfaces is also given. For line correspondence, ambiguities occur if and only if all feature lines are on a special type of algebraic set of dimension 2, called the critical line congruence.
Statistical Analysis of Geometric Computation, 1
Authors: Kanatani Kenichi
Published: November 2023

This chapter is devoted to statistical analysis of errors involved in fundamental geometric computations. The covariance matrices of N-vectors of image points, image lines, and their joins and intersections are computed by introducing a realistic model of noise. Then, we determine the optimal weights for least squares and compute the covariance matrix of the resulting optimal estimate. The result is applied to edge fitting, computation of vanishing points and focuses of expansion, 3-D rotation fitting, and depth computation from stereo. In each problem, characteristic error behaviours are described in detail. We also show that least-squares solutions are in general statistically biased, and derive a scheme for unbiased estimation.
d,q Models for Solid State Power Converters
Authors: Novotny D W , Lipo T A
Published: November 2023

For analysis of motor drives, it is sometimes convenient to characterize the inverter in the same framework as used for the induction motor, that is, in terms of a d,q,O components. As will be shown, the d,q orthogonal reference system also yields converter models which are useful apart from their convenience in combined machine-converter modeling. This is particularly evident when a complex vector d,q representation is employed and the value of such models becomes apparent in later discussion of, for example, current regulated inverters.
Field Weakening Operation
Authors: Novotny D W , Lipo T A
Published: November 2023

So far we have examined carefully how torque can be accurately controlled in an induction motor drive. However, we have made little mention of the demands of the load. Clearly the electromagnetic torque and load torque must be equal in magnitude and opposing in direction during steady state operation. In general we can separate loads into four categories, 1) constant speed, variable or constant torque loads, 2) adjustable speed, constant torque loads, 3) adjustable speed, variable torque loads and 4) variable speed, variable torque loads.
Soft computing applied to intelligent control of AC drives and UPS systems
Authors: Dote Yasuhiko , Hoft Richard G
Published: November 2023

Human thinking has both logical and intuitive or subjective sides. The logical thinking side has been developed and utilized, resulting in present advanced Neumann type computers and expert systems such as hard computing. However, it is found that hard computing cannot give the solution of very complicated problems by itself. In order to cope with this difficulty; the human mind using intuitive and subjective thinking is realized as soft computing which includes neuro- (NN), fuzzy (FL), and chaos (CS) computing, genetic algo rithms (GA), and immune networks (IN). In this chapter soft computing (SC) is introduced to control and make advancements in AC drives and UPS systems. Some examples are also given to explain this technology.
General Introduction
Authors: Solymar L , Webb D J , Grunnet-Jepsen A
Published: November 2023

As mentioned in the Preface, the aim of Part I is to explain a wide range of photorefractive phenomena in the simplest possible terms. We shall always try to emphasize the underlying physical principles, use relatively simple mathematical models, plot lots of curves, and give the more important references.
How Material Proper Ties Influence Light
Authors: Solymar L , Webb D J , Grunnet-Jepsen A
Published: November 2023

In Chapter 2 we answered, in quite some detail, the question: how will the incident optical beams affect the material? In the present chapter we shall try to answer the complementary question: how will the changes in the material affect the optical beams? Let us briefly recapitulate what we have already said in Section 1.3. As a result of the input optical beams there will be a periodic electric field (static or slowly varying) in the photorefractive material. But the material posesses the crucial property, called the linear electro-optic effect, that an electric field E will cause a proportional change in the dielectric constant.
Storage
Authors: Solymar L , Webb D J , Grunnet-Jepsen A
Published: November 2023

Storage was the first application to be suggested for the photorefractive effect and continues to be a promising area for research to this day, as witnessed by the continual steady stream of papers on the subject (see for example the review articles by Pauliat and Roosen (1991) and Hesselink and Bashaw (1993)). The interest is due to the potentially huge amount of information that could be stored holographically in the volume of a photorefractive crystal. There seems to be a real possibility that storage devices based on this technology could be commercialized in the not too distant future.
Electromagnetics
Authors: Reece A B J , Preston T W
Published: November 2023

The electrical engineer is usually interested in the magnitude and distribution of flux density, B, together with related quantities such as magnetising force, H, and winding flux linkages, Φ. Solving for B requires consideration of two vector components, even in two dimensions. Thus, most (though not all) computational methods solve in terms of potentials, which in many practical cases are scalar quantities.
The importance of engineering judgement
Authors: Reece A B J , Preston T W
Published: November 2023

It is hoped that the preceding chapters on the principles of modelling will have demonstrated the frequent need to make engineering judgements. Nevertheless experience has shown that there is a danger, particularly when computer packages are first used, of regarding the process of field solution as a well-defined, almost mechanical one. Consequently insufficient thought may be given to the sound formulation of the problem and to the interpretation of results. Hence a resume of the more important questions which should be considered when deciding the model is appropriate before moving on to the Case Studies of Part 3. Some points arising and some problems and possible approximations in modelling are discussed later.
Turbine-generator end-leakageields and losses
Authors: Reece A B J , Preston T W
Published: November 2023

The designer of turbine generators of high specific ratings needs a method of predicting the field distribution in the end region, the losses and reactance voltages it produces and the forces generated on conductors. The region is of complicated form and includes current-carrying conductors and a variety of materials. Figure 14. l shows a partially wound stator and Fig. 14.2 is a somewhat simplified longitudinal slice through a typical end region, with quantities and areas of special interest indicated.
Introduction
Authors: Hasegawa Akira , Kodama Yuji
Published: November 2023

Optical solitons in fibres attract interest from a wide area of science and technology. The mathematical properties of the model nonlinear SchrÖdinger equation, its integrability in the ideal case and its perturbative properties invite the interest of applied mathematicians. Among solitons which are now believed to exist in various areas of physics, chemistry, and biology, the optical soliton behaves the most ideally in that its behaviour can be described by mathematical models which take into account proper physical properties of fibres and applied perturbations such as amplification. This property is very effective in exploiting the soliton for engineering purposes in particular for applying it to ultra high speed optical communication.
Perturbation Methods
Authors: Hasegawa Akira , Kodama Yuji
Published: November 2023

As we have seen in Chapters 3 and 4, the soliton is a solution of an integrable system (the NLS equation) which is obtained by the leading order approximation of the original equation (the Maxwell equations in a dielectric medium). The most important property of solitons is that even during the process of mutual interaction, each of their identities, such as the amplitude (or width) and velocity (or frequency), remains constant (but not phase shift). This remarkable property of the soliton leads to the concept of the fundamental mode of the nonlinear system. However, in a real situation of physical applications of solitons, we have to consider effects of higher order terms and external perturbations to study the stability of the soliton under the influence of these effects. Here we present several perturbation methods to deal with this issue. In doing so, we first derive in Section 5.1 an infinite number of conservation laws of the NLS equation, the fact of which is a consequence of the integrability and is that which leads to the remarkable property of the soliton solution. In this section, we also discuss the Hamiltonian structure of the NLS equation, and the stability of one soliton solutions. Then we observe how these conserved quantities deteriorate due to perturbations, and in the case of a small perturbation, we see in Section 5.2 that this observation actually determines the behaviour of a perturbed soliton solution. This approach gives a simple method to study a perturbed problem. However, it should be noted that the method gives only limited information on the soliton parameters, and not the structure of solitons including their phase and position. These are essential in considering a multi-soliton perturbation problem.
Reshaping Of Solitons And Concept Of Guiding Centre (Average) Solitons
Authors: Hasegawa Akira , Kodama Yuji
Published: November 2023

A major unsatisfactory feature of the long-distance propagation of a soliton in fibres is the effect of fibre loss. The authors have proposed several methods to compensate for this effect (Hasegawa and Kodama 1982; Kodama and Hasegawa 1982, 1983; Hasegawa 1983, 1984). Among these, the concept of Raman amplification using the fibre Raman gain itself (Hasegawa 1983, 1984) was found to reshape the soliton successfully in experiments by Mollenauer et al. (1985). The effect of repeated Raman amplification was further studied numerically by Mollenauer et al. (1986) and the first successful long distance all optical transmission was demonstrated by Mollenauer and Smith (1988). However, the original idea of simple optical amplification (Kodama and Hasegawa 1982) became feasible because of the discovery of the erbium doped fibre amplifier (Mears et al. 1987; Desurvire et al. 1987). Reshaping solitons by the erbium-doped fibre amplifier was first tested and successfully demonstrated by Nakazawa et al. (1989). As a possible alternative to the erbium-doped amplifier, the use of lumped parametric amplifier has been also proposed by Yuen (1992) (see also Kutz et al. (1993)).
Soliton Transmission Control
Authors: Hasegawa Akira , Kodama Yuji
Published: November 2023

In the previous chapter, the guiding centresoliton was introduced for a system where the loss is compensated for by inserting lumped amplifiers periodically along the transmission line. However an amplification is always accompanied by a superposition of noise, which, due to the nonlinearity of the system, modulates a soliton as it passes through the amplifier. Since the noise is a spontaneous emission, the interaction is small. However, after several hundreds of amplifiers, the effects become large and induce random shifts in soliton parameters. The most troublesome of these effects is the frequency (and the velocity) shift which translates into a random jitter of the position. This effect known as the Gordon-Haus limit (Gordon and Haus 1986) is believed to provide limitation of the capacity of a long-distance communication system (Gordon and Mollenauer 1991; Tang and Ye 1993).
Modulation Instability
Authors: Hasegawa Akira , Kodama Yuji
Published: November 2023

A continuous wave with a cubic nonlinearity in an anomalous dispersion regime is known to develop instability with respect to small modulations in amplitude or in phase, called modulational instability. The phenomenon of modulational instability was discovered in fluids (Ostrovskii 1963, 1966; Whitham 1965; Benjamin and Feir 1967), in nonlinear optics (Bespalov and Talanov 1966; Karpman 1967), and in plasmas (Taniuti and Washimi 1968; Tam 1969; Hasegawa 1970, 1971). Modulational instability of a light wave in a fibre was suggested by Hasegawa and Brinkman (1980) as a means to generate a far infrared light source. Akhmediev et al. (1986, 1987) studied the modulational instability by constructing exact periodic solutions of the NLS equation. The first experimental verification of the modulational instability of a light wave in a fibre was made by Tai et al. (1986a). The modulational instability can also be induced by a mixture of a small amplitude light waves with the frequency separation (with respect to the carrier cw wave) falling into the sideband frequency range of instability (Hasegawa 1984). This induced modulational instability can be used to generate an ultra short pulse train with a desired repetition rate. The first experimental evidence of an induced modulational instability was also produced by Tai et al. (1986b). Modulational instability can also be produced by cross phase modulation (Berkhoer and Zakharov 1970; Agrawal 1987). This chapter is devoted to presenting theoretical and experimental analyses of modulational instabilities in fibres.
Object Recognition
Authors: Rothwell Charles A
Published: November 2023

The task of recognizing objects using computers has been investigated fairly broadly since the earliest days of research into machine vision. However, very few reliable systems exist; those that actually work do so in very specific environments and adapt poorly to other circumstances. Until systems are built which can recognize large numbers of objects from realistic scenes, any claims of success should be treated with caution by an independent observer. There is also a unilateral failure to test systems properly over a large number of varying images and conditions. This may be because the complete system building process takes so long, but it is certainly true that a more concerted effort is required to produce consistent methods of testing by which we can judge our efforts.
My Own Right Time
Authors: Woodward Philip
Published: November 2023

The pendulum never ceases to be a source of interest to scientists, yet the mechanisms used to maintain it in oscillation are strangely neglected in the general history of science and technology. In the past, escapements have received attention from scientists of the first rank, such as Galileo, Huygens, Airy and Kelvin. Others, like John Harrison, Pierre Le Roy, Lord Grimthorpe and William Shortt, to name but a few, are almost unknown outside the horological fraternity. Here I must echo the aspirations of Professor David Landes of Harvard University upon discovering the wealth of interest to be found in the history and science of time measurement.
Disturbed harmonic motion
Authors: Woodward Philip
Published: November 2023

At the age of twenty-five, George Airy (1827) wrote a paper on escapement theory which has stood the test of time and become a classic work. Two months later he was appointed Lucasian Professor of Mathematics at Cambridge University. In 1835 he became Astronomer Royal and in 1871 President of the Royal Society. Today, Airy’s paper would be regarded by mathematical physicists as quite elementary, but few things in science are elementary when being done for the first time.
Error correction
Authors: Woodward Philip
Published: November 2023

No sooner have the hands of a watch or clock been set to the correct time than they will start to wander away from it, and once they have lost the place, so to speak, there is no magic by which they can find it again other than by accident. This is an important point of principle. An independent timepiece is constantly predicting the time by a process of dead reckoning, and it is not to be wondered at that the longer it goes without checking, the farther from the truth it will be. Much of the interest of error analysis stems from the fact that different sources of error grow in different ways and at different rates.
Noise modulation
Authors: Woodward Philip
Published: November 2023

Speak to an audio engineer of ‘white noise’ and he will imagine a rushing sound not unlike what we imagine we hear when we put a seashell to our ear. By analogy with the colours that go to make up white light, the adjective ‘white’ means that the intensity or power of the noise is spread uniformly across the whole band of frequencies with which we happen to be concerned. In the correct jargon, the mean power density with respect to frequency is constant. On an oscilloscope, white noise from whatever source looks something like the record in Figure 14.1, but this particular trace shows noise over a band vastly lower down the scale than any musical sounds, lower even than the sounds of thunder or earthquakes. It is a plot of the rate fluctuations of Shortt clock No. 13 in 1938, compared daily with the ‘rhythmic time signal’ from the Rugby radio transmitter.*: The frequency components to be found here are not to be measured in hundreds or thousands of hertz but in millionths! One millionth of a hertz is one cycle in eleven or twelve days.
The enigma of flicker noise
Authors: Woodward Philip
Published: November 2023

Flicker noise presents applied scientists with a problem. It is a widely observed phenomenon by no means limited to clocks. Originally discovered in thermionic valves, it has turned up in many fields other than electronics - in physics generally, medicine, hydrography, the stock market, and even in modern music (a form of noise) - but it is strangely difficult to explain. A generic mechanism for it has been proposed (West and Shlesinger 1989, 1990), but through my own shortcomings, I have not yet succeeded in finding that explanation helpful.
Wallman’s conjecture
Authors: Woodward Philip
Published: November 2023

Clockwork may already have reached its apogee when it was eclipsed by electronics, but curiosity compels us to ask whether extra time might have improved the score. It is a question which has fascinated many scientific horologists. A generation back, the distinguished names which would have sprung to mind were those of Vannevar Bush and John Early Jackson in the United States, who were convinced that pendulum accuracy still had some way to go. Their well-known project was reported in Scientific American (Strong 1960), but as is so often the case the final outcome of the experiment is obscure; one can only presume that it proved a disappointment. It has been reported (Cain and Boucheron 1994) that Jackson was never able to adjust the spring in the ingenious compensator for circular error. Enthusiasts approaching the subject from every angle are too numerous to name, yet by present-day standards progress has been slow.
Lightwave Communications
Authors: Joindot Michel
Published: November 2023

The history of modern lightwave communications systems began at the end of the fifties, with lasers, which were the first optical source with high power and directivity able to be used in a communication system. Gas lasers, needing high supply voltages and relatively large sized, were followed in 1961 by semiconductor lasers, which appeared much more promising, because of their small dimensions and the possibility of modulating them with low currents. More than ten years of research were necessary to achieve reliable enough semiconductor lasers working at ambient temperature.
Introduction
Authors: Semmens P W B , Goldfinch A J
Published: November 2023

Although British Railways operated its last mainline steam locomotives in August 1968, there is still immense interest in the large numbers of them which have been privately preserved. Not only do these operate on the various heritage railways throughout the country, but a select few are passed to operate trains on parts of National rail’s national system. In the museum world various working reproductions of historic locomotives have been constructed, and there is even a brand-new Class Al Pacific being assembled in Darlington at the time of writing. (The former are correctly referred to as ‘reproductions’, rather than ‘replicas’, because they differ in numerous details from the originals, although mirroring fairly accurately their appearance. There is no way in which designs of anything getting on for two centuries old would meet today’s safety standards.)
Transmitting the power
Authors: Semmens P W B , Goldfinch A J
Published: November 2023

In the same way as a heavy lorry has a chassis on which are mounted its motor, transmission, wheels, cab and load, a steam locomotive is constructed around its frames, which, in effect, carry its personal identity. When a locomotive was overhauled, particularly in a major railway’s Main Works, the boiler and many other smaller components became dispersed for repair, and could subsequently appear on various other locomotives of the same type, but the frames retained the machine’s original running number. Only in the largest repair establishments was any spare set of frames kept, and then only for numerically-large classes. These could be substituted, say, when a locomotive which had been particularly badly damaged in an accident arrived for overhaul.
Brakes
Authors: Semmens P W B , Goldfinch A J
Published: November 2023

One of the surprising things about the early steam locomotives was that many of them were not provided with any brakes. In that respect, however, they did not differ from the four-legged contemporary alternative form of motive-power, which was not able to provide much in the way of braking effort to supplement what, if any, was fitted to the vehicles they hauled. Well into the twentieth century, too, it was not unknown for horses to bolt, dragging their load at a high speed through the streets, so the idea of a runaway train did not concern the railway pioneers unduly. In the early days of the steam locomotive, when George Stephenson was asked what would happen if Rocket came across a cow on the line, he is reputed to have replied ‘It would be so much the worse for the coo’! However, had there been investigative journalism in those days, he might have had occasion to regret this statement when that locomotive fatally ran down the President of the Board of Trade at the opening of the Liverpool & Manchester Railway in 1830. (Railways in the UK are nevertheless still required to provide fencing through the countryside that is ‘stock-proof’.)
Elementary considerations
Authors: Scaife B K P
Published: November 2023

Our concern is with the behaviour of insulating materials subjected to electric fields. There is no such thing as a truly insulating substance, that is a material which will obstruct, under all circumstances, the transport of electric charge through it. There is, however, a very large group of materials which may be regarded as electrical insulators in view of their exceptionally low conductivities, ranging from 10-18 S/m to 10-6 S/m; metals have conductivities of the order of 108 S/m, and silicon has an intrinsic conductivity, at room temperature, of the order of 10 S/m (Sillars 1973; Tareev 1975; Blythe 1979).
Basic principles of the calculation of the relative permittivity
Authors: Scaife B K P
Published: November 2023

From the preliminary discussion in Chapter 1 it is dear that the calculation of the relative permittivity, E, in terms of molecular parameters requires a study of the manner in which a vast number of particles react to the imposition of an external electric field. There are two aspects to this: the response of an individual particle to an electric field, and the possible modification of this response by particle interactions.We shall consider the parameters such as molecular polarizability and molecular dipole moment to be given and we shall not attempt to discuss their theoretical foundations.
Electromechanical effects
Authors: Scaife B K P
Published: November 2023

In general, dielectric polarization is always accompanied by mechanical effects which, to a first approximation, depend quadratically on the potential gradient.A dielectric body situated in a non-uniform electric field will be subjected to a net mechanical (ponderomotive) force which may be readily measured. In other situations, where there is no net force, the mechanical concomitants of electrical polarization, apart from a possible torque, are usually very small and much less easily observed.
The electromagnetic field in matter
Authors: Scaife B K P
Published: November 2023

Electromagnetic fields are described by Maxwell’s equations, which are mathematical expressions of basic laws associated with the names of Gauss, Ampère, Faraday and Maxwell.The aim of this chapter is the provision of an explanation of the, so-called, macroscopic Maxwell equations, eqn (1.87), in terms of microscopic variables.
The need for courageous action to prevent obesity
Authors: Brownell Marlene B , Schwarz Kelly D
Published: November 2023

Experts have implored the world for years to take note that obesity, poor diet, and physical inactivity are major public health issues. The world now notices. Health authorities throughout the world now devote considerable attention to at least discussing obesity. Attention from the press and the public has grown as well. There were 4767 obesity-related stories in the media for the 12-month period ending September 2003, a ten-fold increase from the same period ending September 2000 (1).
Thus Spoke Galileo
Authors: Frova Andrea , Marenzana Mariapiera , Mcmanus Jim
Published: November 2023

You might know what is said about Galileo, but not many people know what Galileo himself actually said! His elusive and often misquoted discourse has resulted, over the years, in slurs against his name and reputation as a scientist. Let him speak then, so that he can bring to everyone's attention his message of reason, of intellectual honesty, and of free thinking. A message that, more than ever, is of great relevance in the rampant irrationality of the new millennium. The exposition begins with a blunt 'self-portrait'. A 'forgery' of course, based mainly on extracts from Galileo's writings and private letters; something he would never have dared, nor been allowed, to write for the public. The selection of writings offered includes many of the subjects that were closest to Galileo's heart and mind with lively commentary from both the literary, scientific, and historical viewpoints. For those who want to know the mathematics behind Galileo's theories, each chapter closes with a separate self contained summary. Thus Spoke Galileo will allow the reader to appreciate the work and the writing-style of a great scientist and author who had a tremendous influence on the modern world.
Feynman Diagrams and Pair Interactions
Authors: Bruus Henrik , Flensberg Karsten
Published: November 2023

It is in the case of interacting particles and fields that the power of quantum field theory and Feynman diagrams really comes into play. In this chapter, we develop the Feynman diagram technique for a system of fermions with pair interactions. The primary example we will work with is a gas of fermions interacting through Coulomb interactions, but the technique is derived in a more general framework. In general, the Hamiltonian has two parts H = H  0 + W .
1D Electron Gases and Luttinger Liquids
Authors: Bruus Henrik , Flensberg Karsten
Published: November 2023

The 1D interacting electron gas is very different from its higher dimensional counterparts. The main difference being the breakdown of Fermi liquid theory in 1D. In Chapter 15 we saw that the main achievement of the Fermi liquid theory is that it enables us to picture the elementary excitations in terms of quasi particles. As we shall see in this chapter, the quasi particle excitations are in 1D electron systems replaced by the Luttinger–Tomonaga excitations, a sort of density waves, having a completely different nature. The corresponding electron liquid is denoted the Luttinger liquid.
Early works
Authors: Challet Damien , Marsili Matteo , Zhang Yi-Cheng
Published: November 2023

The Minority Game was introduced and first studied in 1997 (Challet and Zhang 1997). Thereafter, the then tiny community of ‘econophysics’ caught on to it and published, in a period of merely 5 years, over one hundred papers directly concerned with it. This can be considered ‘explosive’ activity in economics, where typical publication times are excruciatingly slow. The reason why almost all the papers related to the Minority Game were published in interdisciplinary physics journals is that there exist multiple hurdles for outsiders like physicists publishing in the mainstream economics venues. Definitely physicists generally feel uneasy about several pillars of mainstream economic theory, such as rational expectations, the efficient market hypothesis and the notion of equilibria to name a few. This approach looks too axiomatic and formal to deal with such complex systems as, for example, financial markets.
Quantum mechanics
Authors: Fox Mark
Published: November 2023

The attribution of a wave function to particles with non-zero rest mass like electrons is called first quantization. The reverse procedure, namely the attribution of particle-like properties to wave fields (e.g. the electromagnetic field), is called second quantization. This chapter, in common with most introductory treatments of quantum mechanics, deals only with first quantization. The formalism of second quantization uses the number representation described in Chapter 8.
Photon antibunching
Authors: Fox Mark
Published: November 2023

In the previous chapter we studied how light beams can be classified according to their photon statistics. We saw that the observation of Poissonian and super Poissonian statistics could be explained by classical wave theory, but not sub Poissonian statistics. Hence sub-Poissonian statistics is a clear signature of the photon nature of light.
Working in Clinical Neuropsychology
Authors: Carpenter Katherine , Tyerman Andy
Published: November 2023

Clinical neuropsychology is concerned with people whose thinking, behaviour, or emotions have become disrupted as a result of brain damage. Such neuropsychological changes often have a major effect on the person and their lifestyle, occupation, and family relationships. Clinical neuropsychology has its own specialist knowledge base of neurology, neuroanatomy, and brain–behaviour relations. However, it still involves work with people with their own everyday life events and stresses who experience psychological problems (such as anxiety and depression) similar to those in mental health settings, in addition to their specific neuropsychological changes.
Conclusion: Working in Changing Contexts and Changing Practice
Authors: Hall John , Llewelyn Susan
Published: November 2023

This final chapter draws together a number of themes that emerge from the preceding chapters. It provides, first, an overview of the contextual, social, and policy issues which have an impact on clinical psychology as a profession, and which have been described in many of the chapters. It then considers the conceptual, professional, and ethical responses of clinical psychology to these issues, leading to potential changes in modes of practice. We are attempting to gaze into a crystal ball in this chapter, which is of course likely to be doomed to failure, as nobody can accurately read the future.
DNA on surfaces
Authors: Bates Andrew D , Maxwell Anthony
Published: November 2023

The development of the ideas of linking number, twist and writhe (Chapter 2) has provided powerful concepts for understanding the geometry of supercoiled DNA. However, we have seen that the actual values of twist and writhe are difficult to determine, except in a few specialized cases (Chapter 2, Section 2.4.1). An important factor that can modulate DNA supercoiling is the wrapping of the DNA on a protein surface, where, in a closed-circular molecule, the writhing of the DNA around the complex and any changes in twist of the DNA helix contribute to the overall supercoiling of the molecule.
Knots and catenanes
Authors: Bates Andrew D , Maxwell Anthony
Published: November 2023

To most people the word ‘knot’ conjures up images of boy scouts and bowlines, but, in the context of this book, it refers to ‘topological’ knots in DNA. The distinction between the everyday sense of the word ‘knot’ (as applied, for example, to a piece of string) and a topological knot, is that the latter must be a closed curve. Like linking number (Chapter 2, Section 2.3.1), topological knotting is a concept that is only meaningful in a closed curve.
Biological consequences of DNA topology
Authors: Bates Andrew D , Maxwell Anthony
Published: November 2023

We hope that by the time you have reached this chapter you will have a good grasp of the concepts of DNA topology and will appreciate that it is an unavoidable issue when dealing with virtually any naturally occurring DNA molecule. The purpose of this chapter is to put DNA topology into the context of important biological processes: DNA replication, transcription, and recombination.
Origin and significance of Special Relativity
Authors: Giulini Domenico
Published: November 2023

The year 1905 is commonly known as Einstein’s miraculous year. In that year, the just 26 year old patent clerk Albert Einstein (1879–1955)—at this time still a scientific nobody—published five seminal papers in the prestigious German physics journalAnnalen der Physik, each of which had a major impact on the future development of physics. (A book containing all five papers in English translation appeared a fewyears ago [1], nowalso available as an e-Book.)
The Foucault pendulum
Authors: Baker Gregory L , Blackburn James A
Published: November 2023

The sphere, hanging from a long wire set in the ceiling of the choir, swayed back and forth with isochronal majesty … I knew the earth was rotating, and I with it, and Saint-Martin-des-Champs and all Paris with me, and that together we were rotating beneath the Pendulum, whose own plane never changed direction, because up there, along the infinite extrapolation of its wire beyond the choir ceiling, up toward the most distant galaxies lay the Only Fixed Point in the universe, eternally unmoving.

With a novelist’s hyperbole, Umberto Eco begins his unusual tale entitled Foucault’s Pendulum. It is a story of innocent diversions that turn into consuming reality, of fictitious plots, hatched by three unlikely dreamers with their word-randomizing computer, that strangely coincide with ancient diabolical schemes. These fictitious schemes would reach fruition in the former church, Saint Martin des Champs—now part of the Conservatoire National des Arts et Métiers (CNAM) in Paris, that has housed a Foucault pendulum since 1855. The plot of Eco’s novel has little to do with the physics of the pendulum, except that the pendulum’s regularity provides, as with Poe’s story, a prominent and ominous symbol. Through symbolism of the pendulum and many classical allusions, Eco’s tale builds a crescendo of dread toward the horror of its final conclusion.