bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ideal Distributions
Authors: Shmueli Uri , Weiss George H 
Published: November 2023

Abstract
In our explicit calculation of the asymptotic form of the pdfs for the magnitude of the structure factor in space groups Pl and PI we showed that the characteristic function for the equal-atom case approaches a pure or modified Gaussian form when the number of atoms in the unit cell is large. In this section we show that the Gaussian limiting form is to be expected under more general circumstances than the equal-atom case for the two space groups analysed in Chapter 2. Indeed, the Gaussian limit is nearly always the starting point for investigations of both intensity statistics and direct methods in the crystallographic literature. In the mathematical literature the circle of ideas related to this Gaussian behaviour is known as the central limit theorem (e.g. Cramer 1946; Feller 1971). This theorem first appeared with specific reference to crystallographic applications in a paper by Wilson (1949). The results of this investigation are generally referred to as the ‘Wilson statistics’, and have had a great influence on the further development of crystallographic statistics including direct methods. Since the central limit theorem plays such an important role in crystallography it is useful to discuss some of the more elementary ideas behind this much used tool.
Fourier Representations of Pdfs in Direct Methods of Phase Determination
Authors: Shmueli Uri , Weiss George H 
Published: November 2023

Abstract
The role of probabilistic relationships in direct methods of phase determination has been of major importance in crystallographic practice during the past four decades. It has been documented in the crystallographic literature, mainly in Acta Crystallographica and in a number of books and monographs. The extension from pdfs of the magnitude of a single structure factor, of importance in intensity statistics, to the joint pdfs of several structure factors, on which direct methods of sign and phase determination are based was first discussed in the well-known monograph of Hauptman and Karle (1953b). A number of joint pdfs are further developed in the papers of Vand and Pepinsky (1953), Woolfson (1954), Cochran and Woolfson (1955) and Cochran (1955), and in many subsequent publications by Karle and Hauptman. An early and very clear exposition of corrections to Gaussian approximations of joint pdfs of several centrosymmetric structure factors was presented by Klug (1958) and both the centrosymmetric and non-centrosymmetric cases, using the Edgeworth expansion, are treated in two detailed papers by Naya, Nitta and Oda (1964,1965). Gaussian approximations to the joint pdfs of three structure factors were summarized by Woolfson (1961) and Karle and Karle (1966), who also proposed multisolution techniques that rendered the solution of the phase problem for crystals of small and medium-sized molecules a practical proposition.
The Fundamental Approach
Authors: McComb W D 
Published: November 2023

Abstract
Superficially the background material presented in this chapter may seem very similar to the topics covered in Chapter 1. That is, we begin with the Navier-Stokes equations and use the Reynolds averaging procedure to formulate the statistical approach. Then (just as in Chapter 1) we are concerned with the mean square excitation of fluctuations, with energy balances, and with the moment closure problem. We shall also consider the use of both dimensional methods and approximate models, and conclude by considering some representative experimental results. However, there will be two important differences of emphasis. First of all, our main interest will be in the underlying structure of the turbulence. That is, we shall consider the correlation of velocities at two or more points (and times). The foundations of this approach were laid by Taylor (1935) in a paper which also introduced the concepts of statistical homogeneity and isotropy: a step which took turbulence theory into the realm of physics, rather than engineering. In a subsequent paper (Taylor 1938a) the introduction of the energy spectrum in wavenumber (i.e. the Fourier transform of the two-point correlation in space) virtually completed this process, and, as we shall see, the calculation of this spectrum provides a major goal for fundamental turbulence theory.
Some Recent Developments In The Study Of Turbulence
Authors: McComb W D 
Published: November 2023

Abstract
This chapter is somewhat miscellaneous in character and is intended to serve two purposes. The first of these is to cover certain topics which would not easily fit into the main part of the book, yet which are important. The sections on anemometry, data processing, and engineering models are the main topics in this category. The second purpose is to try to give the reader a broad picture of what the rest of the book is about. That is, certain sections of this chapter should act as both an introduction to and an overview of more detailed and advanced treatments later in the book. For example, the section on renormalized perturbation methods is mainly descriptive, using only rather simple mathematics to explain the general method.
Numerical Simulation Of Turbulence
Authors: McComb W D 
Published: November 2023

Abstract
In recent times, the rapid growth in both size and speed of digital computers has tended to change our perception of the turbulence problem. Twenty or so years ago, the clear aim-shared by engineers and theorists alike-was to derive transport equations by averaging the Navier-Stokes equation. Nowadays, the possibility of computers becoming powerful enough to simulate some flows of engineering interest leads us to consider a simplified form of the turbulence problem: in broad terms, can we use fundamental approaches to reduce the number of degrees of freedom? That is, can we reduce the size of the task for numerical simulation? It is because we must now consider questions of this kind that we include here a short treatment of numerical simulation (in itself, a large and important subject) as a coda to our treatment of the statistical theory of turbulence. In doing this, we shall have three broad purposes in mind.
Coherent Structures
Authors: McComb W D 
Published: November 2023

Abstract
Organizing a logical account of a fashionable and fast-growing subject, like the study of coherent structures (or recognizable ‘deterministic’ patterns) in turbulent flows, is not without its difficulties. To begin with, quite a variety of such structures has now been identified, and, although different structures can appear to be very different phenomena, clearly they must all be facets of the same basic phenomenon, if only at the level that they are all solutions of the Navier-Stokes equation! At the present time, the safest way of tackling the problem of taxonomy, it seems to us, is to make a subdivision of the subject into very broad generic classes. For instance, a division into flows without solid boundaries--where coherent structure emerges rather easily as an organized vortex pattern-and flows with solid boundaries-where the coherent structure is not so easily seen, and requires a good deal of careful elucidation-seems likely to prove helpful, if only because such a division has tended to reflect different schools of activity.
In Situ Survey by Wave Propagation
Authors: Ishihara Kenji 
Published: November 2023

Abstract
When a body wave comes across an interface of two media with different stiffnesses, the direction of its propagation is deflected in accordance with Snell’s law as illustrated in Fig. 5.1. If the angle of incidence ψ1 is smaller than a critical angle ψc, the wave is refracted and propagates in the second medium with an angle ψ2 which is larger than ψ1 (where we have assumed that the wave travels faster in the second medium). If the incident wave encounters the interface with an angle larger than ψc, the wave is reflected into the first medium with the same angle ψR to the vertical, as illustrated in Fig. 5.2.
Effect of Loading Speed and Stiffness Degradation of Cohesive Soils
Authors: Ishihara Kenji 
Published: November 2023

Abstract
The tendency of soils to dilate or to contract during drained shear and pore water pressure changes during undrained shear does not come out in the infinitesimal or small strain ranges. The effect of the dilatancy begins to manifest itself as the magnitude of shear strain increases above the level of about 10-3 as indicated in Section 1.3. It should be remembered that the major changes in soil properties due to cyclic loading such as degradation in stiffness of saturated soils or hardening of dry and partially saturated soils can occur as a consequence of the dilatancy effect being manifested during cyclic loading. Thus the effect of load repetition as described in Section 1.2.2 begins to crop up when the strain induced in soils grow above the level of 10-3. This effect is alternatively called cyclic degradation.
Analysis of Liquefaction
Authors: Ishihara Kenji 
Published: November 2023

Abstract
The cyclic shear stress induced at any point within a level ground during an earthquake due to upward propagation of shear waves can be assessed by means of a simple procedure proposed by Seed and Idriss (1971). If a soil column to a depth z is assumed to move horizontally as shown in Fig. 2.4 and if the peak horizontal acceleration on the ground surface is amax, the maximum shear stress πmax acting at the bottom of the soil column is given by,
Heat Transfer By Conduction And Convection
Authors: Lawton B , Klingenberg G 
Published: November 2023

Abstract
Temperature is usually thought of as the degree of hotness of a material. When a spatial temperature difference occurs, heat flows from the hot region (heat source) to the cool region (heat sink) until the temperature difference is eliminated. The hot region loses energy and the cool region gains energy so it is useful to think of heat transfer as energy transfer by virtue of a temperature difference. This process does not occur instantly but requires a certain time, and so heat transfer is the study of the relationships between energy, temperature, spatial coordinates, time, and the properties of the materials involved.
Radiation And Radiation Transport
Authors: Lawton B , Klingenberg G 
Published: November 2023

Abstract
This chapter covers the fundamental definitions and laws of thermal radiation, elementary spectroscopy, radiation transport, absorption and scattering by particles. and radiation transport in the presence of scattering particles. [t is useful in defining the notation more closely hut may be omitted by readers who are already famili.ir with radiation theory. Its main value is, perhaps, to engineers whose first degree concentrates typically on radiation exchange between surfaces and often ignores the absorption, emission, and catering of radiation passing through a gap .
Large-Volume Anvils
Authors: Eremets M I 
Published: November 2023

Abstract
After consideration of the anvil system in general, we deal with particular anvil apparatus. Nowadays the diamond cell has become the most popular anvil apparatus. It will be considered separately (Chapter 3) and the rest of this book is devoted to a large extent to different applications of a DAC. However, a DAC has a significant drawback - a very small working volume. In this chapter, the anvil apparatus having a working volume orders of magnitude larger than for a DAC is considered. Complicated and cumbersome apparatus such as multianvil presses or ‘belt’ are not considered, because they are well documented and are not convenient for experimental applications. Instead, the main attention will be devoted to apparatus of the Bridgman type.
Pressure Measurement
Authors: Eremets M I 
Published: November 2023

Abstract
The pressure scale is well established only in the range to about 2.6 GP a where pressure is obviously defined as the ratio of load applied to a piston to the cross-sectional area of the piston. Different approaches to constructing an absolute pressure scale in the mega bar region are described in this chapter. Attention is mainly devoted to practical pressure scales, and in the first place the ruby scale. Features of pressure determination at low and high temperatures are discussed in the corresponding chapters. Examples of different pressure gauges for measurements under appropriate conditions are scattered through the book.
Brillouin Scattering
Authors: Eremets M I 
Published: November 2023

Abstract
Brillouin scattering is the inelastic interaction of light with acoustic phonons which results in a shift in the frequency of scattered radiation. This effect is similar to Raman scattering, but information is obtained abont acoustic branches of the phonon spectrum. Velocities of elastic waves, the complete set of elastic constants of materials, and much information in combination with other measurements can be obtained. An important feature of Brillouin scattering is the sensitivity to anisotropy of even cubic crystals where the dielectric constant is scalar and Raman and IR absorption are also isotropic. Selection rules allow always at least one mode to be observed, in contrast to Raman scattering and IR absorption, which fail, for example, in the case of rare-gas crystals. Brillouin scattering is one of the few techniques for obtaining some information about the phonon spectrum in these materials, as well as elastic and relaxation properties of viscoelastic liquids and amorphous materials.
Magnetic Studies Under Pressure
Authors: Eremets M I 
Published: November 2023

Abstract
Magnetism is an extensive field of solid-state physics. Here again, as in other fields, pressure is a powerful parameter, which allows the distance between magnetic moments to be changed and may cause a variety of magnetic transitions and other phenomena. A very effective method is to study the critical temperature and field of superconductors under pressure - Tc(P) and Hc(P) - to test different theories describing of superconductivity. Tc, in particular, can be determined by recording the change in magnetic moment due to repulsion of a magnetic flux in the superconductive state.
Technology of reactive ion etching
Authors: Handa S 
Published: November 2023

Abstract
The original meaning of ‘etching’ is ‘to eat’; the process of removing something from an object. Moreover, it is impressive that another original meaning of it is ‘to feed’. In fact, reactive ion etching (RIE) consists of two processes; ‘to eat’ and ‘to feed’. The physical process of etching is to remove particles from a solid surface by the colliding energy of ions which is converted into thermal, chemical, or kinetic energy. The mechanisms of etching can be classified by forms of energy exchange: chemical and physical. The etched pattern can be classified into two types: anisotropic (directional) etching and isotropic (indirectional) etching. When thermal and chemical energies are transformed in the reaction, then indirectional etching will be processed. Liquid chemical etching is a typical example of indirectional etching.
Introduction To Velocity Measurements
Authors: Bruun H H 
Published: November 2023

Abstract
To explain the concepts and principles of practical velocity measurements by hot-wire anemometry (HWA), consider the case of a hot-wire probe containing one or more sensors placed in a fluid flow. The purpose of the sensors is to provide information related to the velocity vector at the centre point of the hot-wire element(s). For the discussion contained in Chapters 3 to 6, the flow will be assumed to be isothermal and the density p will be assumed to be constant. The velocity field will be described by the velocity vector, V, at the point of the sensing element(s), where Vis a function of time for a turbulent flow. The direct output voltage from the anemometer is denoted by E, with indices of 1, 2, etc., in the case of a multi-sensor probe.
Numerical Techniques And Computer Applications
Authors: Guthrie R I L 
Published: November 2023

Abstract
Numerical methods for solving differential equations have become a very powerful weapon in the armoury of the practising engineer, following the widespread availability of high-speed digital computers since the early l 960s. Prior to that time, realistic solutions to commonplace engineering problems involving heat, mass, or momentum transfer were not easily obtained, except in those particular cases in which the boundary conditions were ‘well set’ and analytical solutions were available. Some of these, such as the error function solutions and series solutions have already been presented in preceding chapters.
Computation of 3-D Rotation
Authors: Kanatani Kenichi 
Published: November 2023

Abstract
This chapter focuses on 3-D rotations. A 3-D rotation is represented by a rotation matrix-an orthogonal matrix of determinant 1. We first review how a rotation matrix is expressed in terms of its axis and angle of rotation. Then, we discuss the problem of computing the rotation which best maps a given set of vectors to another set of vectors. This problem is analytically solved by three different methods—polar decomposition, singular value decomposition, and quaternion representation. These techniques are applied to two problems. One is orthogonality fitting—fitting three mutually orthogonal lines to three not necessarily orthogonal orientations. The other is orthogonal frame reconstruction-reconstructing an orthonormal system of vectors from its projection. This problem is formulated as a mapping from what we call a degenerate matrix to a rotation matrix. In order to solve this problem, we present a computational procedure called optimal resolution, which will play a crucial role in 3-D motion analysis (Chapter 6). Finally, we discuss numerical optimization techniques involving 3-D rotations.
Analysis of Optical Flow
Authors: Kanatani Kenichi 
Published: November 2023

Abstract
If the motion of objects (or the camera) is very small, the corresponding image motion defines an optical flow. Since the displacement of each image point is small (theoretically infinitesimal), it appears that computations based on optical flow are unstable and sensitively affected by image noise. However, the use of optical flow has the advantage that the flow is detected densely (usually at each pixel) over the entire frame by straightforward operations, whereas matching feature points over multiple frames for a finite motion is a very difficult task. Hence, it is expected that a reliable 3-D interpretation can be obtained from optical flow by optimization over the entire frame. As in the case of finite motion, we begin with planar surface motion and derive an analytical solution. Planar surface optical flow is easily determined by two methods—the flow-based approach and the contour-based approach. We then go on to general optical flow and present a robust analytical procedure. This procedure is almost identical to that for finite motion-all we need to solve is the epipolar equation written in terms of the essential parameters and the twisted optical flow. In order to ensure robustness in the presence of noise, the problem is also formulated in the form of optimization in two different ways. Finally, the critical surface that yields ambiguous 3-D interpretations is discussed.
Statistical Analysis of Geometric Computation, 2
Authors: Kanatani Kenichi 
Published: November 2023

Abstract
In this chapter, the techniques of statistical analysis established in Chapter 9 are applied to some of the most fundamental problems of machine vision. First, the reliability of focal length calibration is evaluated in statistical terms. We derive an optimal scheme for maximizing the reliability of the computed focal length and compute its confidence interval. Then, the error behaviours involved in 3-D motion estimation and conic fitting are analysed in detail. In each problem, the least-squares solution is shown to be statistically biased. We construct an unbiased estimation scheme and give numerical examples to demonstrate its effectiveness. Finally, a hypothesizing and testing approach is presented for making judgements concerning edge groupings, vanishing points, focuses of expansion, and vanishing lines. It is shown that the “credibility” of a given configuration can be computed by regarding “edges” as atomic elements and applying the X 2-test, which allows us to compare the credibilities of different configurations on the same basis.
d,q Modelling of Induction and Synchronous Machines
Authors: Novotny D W , Lipo T A 
Published: November 2023

Abstract
The induction motor is truly the workhorse of the industrial world. Until recently, however, they were limited only to driving loads which required nearly constant speed (or at best several discrete speeds) since the efficiency of the motor suffered drastically as the speed was lowered below the rated speed. With the advent of variable frequency power supplies this problem has been largely overcome. However, costs associated with the inverter have thus far prevented across the board replacement of de motors by ac induction motor drives. Analysis of induction machines is typically presented by means of the so called per phase equivalent circuit. However, this model proves inadequate when applied to dynamic conditions as encountered in a variable frequency drive.
Principles of Vector Control and Field Orientation
Authors: Novotny D W , Lipo T A 
Published: November 2023

Abstract
In this chapter the basic concepts of torque control and field orientation are introduced based on steady state considerations for both synchronous and induction machines. A basic set of three requirements which enable direct control of machine torque production is developed and used to illustrate the type of controller needed in both types of ac machines. These controllers are generally referred to as vector controllers because they control both the amplitude and phase of the ac excitation. The vector control of currents and voltages results in control of the spatial orientation of the electromagnetic fields in the machine and has led to the term field orientation [l,2,3]. Usually, this term is reserved for controllers which maintain a 90° spatial orientation between critical field components and hence we will adopt the term field angle control or simply angle control for systems which depart from the 90” orientation. The dynamic performance of the systems outlined in this chapter is considered in later chapters.
Effects of magnetic saturation
Authors: Vas Peter 
Published: November 2023

Abstract
In this chapter the effects of main flux saturation the equations required for the various implementations of vector control (e.g. rotor-flux-oriented control, magnetizing-flux-oriented control, stator-flux-oriented control) are discussed for both smooth-air-gap and salient-pole machines. However, only the derivation and a brief description of the required equations is given, since these can be applied similarly to the corresponding equations derived in Chapters 3 and 4, which, however, are only valid under linear magnetic conditions. It will be shown that as a result of saturation, the linear equations are modified and to obtain the required decoupling between the flux- and torque-producing currents of the machine under consideration, it is these equations which have to be considered when the machine operates under saturated conditions.
Artificial-intelligence-based steady-state and transient analysis of electrical machines and drives; Al-based estimators
Authors: Vas Peter 
Published: November 2023

Abstract
Traditionally mathematical-model-based analysis techniques have always been used for the steady-state and transient analysis of electrical machines. There are many techniques, but they mainly differ in their complexity and the many assumptions used. One of the most popular techniques relies on space-vector theory and is extensively used worldwide, and it is this technique which has also been extensively used in the present book for the development of various high performance, instantaneous torque-controlled drives.