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Gradiometry is a multidisciplinary area that combines theoretical and applied physics, ultra-low noise electronics, precision engineering, and advanced signal processing. All physical fields have spatial gradients that fall with distance from their sources more rapidly than the field strength itself. This makes the gradient measurements more difficult. However, there has been a considerable investment, both in terms of time and money, into the development of various types of gradiometers driven by the extremely valuable type of information that is contained in gradients. Applications include the search for oil, gas, and mineral resources, GPS-free navigation, defence, space missions, medical research, and some other applications. The author describes gravity gradiometers, magnetic gradiometers, and electromagnetic (EM) gradiometers. The first two types do not require any active sources of the primary physical fields whose gradients are measured, such as gravity field and ambient magnetic field. EM gradiometers do require a primary EM field, pulsed, or sinusoidal, which propagates through media and creates a secondary EM field. The latter one contains information about the non uniformness of electromagnetically active media such as conductivity and magnetic permeability contrasts. These anomalies are the boundaries of mineral deposits, oil and gas traps, underground water reserves, buried artifacts, unexploded ordnance (UXO), nuclear submarines, and even cancerous human tissue. This book provides readers with a comprehensive introduction, history, potential applications, and current developments in relation to some of the most advanced technologies in the 21st Century. Most of the developments are strictly controlled by Defence Export Control rules and regulations, introduced in all developed countries that typically require permission to transfer relevant information from one country to another. The book is based on the materials that have been available in public domain such as scientific journals, conferences, extended abstracts, and online presentations. In addition, medical applications of EM gradiometers are exempt from any control, and some new results relevant to breast cancer early detection research are published in this book for the first time.

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Nature continuously presents a huge number of complex and multi-scale phenomena, which in many cases, involve the presence of one or more fluids flowing, merging and evolving around us. Since its appearance on the surface of Earth, Mankind has tried to exploit and tame fluids for their purposes, probably starting with Hero's machinery to open the doors of the Temple of Serapis in Alexandria to arrive to modern propulsion systems and actuators. Today we know that fluid mechanics lies at the basis of countless scientific and technical applications from the smallest physical scales (nanofluidics, bacterial motility, and diffusive flows in porous media), to the largest (from energy production in power plants to oceanography and meteorology). It is essential to deepen the understanding of fluid behaviour across scales for the progress of Mankind and for a more sustainable and efficient future. Since the very first years of the Third Millennium, the Lattice Boltzmann Method (LBM) has seen an exponential growth of applications, especially in the fields connected with the simulation of complex and soft matter flows. LBM, in fact, has shown a remarkable versatility in different fields of applications from nanoactive materials, free surface flows, and multiphase and reactive flows to the simulation of the processes inside engines and fluid machinery. LBM is based on an optimized formulation of Boltzmann's Kinetic Equation, which allows for the simulation of fluid particles, or rather quasi-particles, from a mesoscopic point of view thus allowing the inclusion of more fundamental physical interactions in respect to the standard schemes adopted with Navier-Stokes solvers, based on the continuum assumption. In this book, the authors present the most recent advances of the application of the LBM to complex flow phenomena of scientific and technical interest with particular focus on the multi-scale modeling of heterogeneous catalysis within nano-porous media and multiphase, multicomponent flows.

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Volume 2 of the book begins with chapter 6, in which we have taken up conventional MWTs (such as TWTs, klystrons, including multi-cavity and multi-beam klystrons, klystron variants including reflex klystron, IOT, EIK, EIO and twystron, and crossed-field tubes, namely, magnetron, CFA and carcinotron). In chapter 7, we have taken up fast-wave tubes (such as gyrotron, gyro-BWO, gyro-klystron, gyro-TWT, CARM, SWCA, hybrid gyro-tubes and peniotron). In chapter 8, we discuss vacuum microelectronic tubes (such as klystrino module, THz gyrotron and clinotron BWO); plasma-assisted tubes (such as PWT, plasma-filled TWT, BWO, including PASOTRON, and gyrotron); and HPM (high power microwave) tubes (such as relativistic TWT, relativistic BWO, RELTRON (variant of relativistic klystron), relativistic magnetron, high power Cerenkov tubes including SWO, RDG or orotron, MWCG and MWDG, bremsstrahlung radiation type tube, namely, vircator, and M-type tube MILO). In Chapter 9, we provide handy information about the frequency and power ranges of common MWTs, although more such information is provided at relevant places in the rest of the book as and where necessary. Chapter 10 is an epilogue that sums up the authors' attempt to bring out the various aspects of the basics of and trends in high power MWTs.

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Our aim in this book is to present a bird's-eye view of microwave tubes (MWTs) which continue to be important despite competitive incursions from solid-state devices (SSDs). We have presented a broad and introductory survey which we hope the readers would be encouraged to read rather than going through lengthier books, and subsequently explore the field of MWTs further in selected areas of relevance to their respective interests. We hope that the present book would motivate newcomers to pursue research in MWTs and apprise them as well as decision makers of the salient features and prospects of as well as the trends of progress in MWTs. The scope of ever expanding applications of MWTs in the high power and high frequency regime will sustain and intensify the research and development in MWTs in coming years.

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Waves are everywhere in our daily life. We all experience sound and light with our ears and eyes, we use microwaves to cook, and radio waves are transmitted from and are received by our cell phones. These are just some examples of waves that carry energy from point A to B. However, we may not know details of the physics underlying all these waves. It is important to understand the mechanisms that generate wave dynamics for a given system. It is not straightforward to explain how an electromagnetic ï¬eld becomes oscillatory and propagates as a wave. Waves sometimes represent the underlying dynamics of observed phenomena at a fundamental level of physics. This book is designed to explore these mechanisms by discussing various aspects of wave dynamics from as many perspectives as possible. The target audiences are undergraduate students majoring in engineering science and graduate students majoring in general engineering. Going beyond the typical approach to learning science, this book discusses wave dynamics and related concepts at various levels of mathematics and physics, sometimes touching on profound physics behind them. This book was written to help readers learn wave dynamics on a deep physical level, and develop innovative ideas in their own fields.

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The book is an introduction to the subject of fluid mechanics, essential for students and researchers in many branches of science. It illustrates its fundamental principles with a variety of examples drawn mainly from astrophysics and geophysics as well as from everyday experience. Prior familiarity with basic thermodynamics and vector calculus is assumed.

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This book and its sequel (Theories of Matter Space and Time: Quantum Theories) are taken from third and fourth year undergraduate Physics courses at Southampton University, UK. The aim of both books is to move beyond the initial courses in classical mechanics, special relativity, electromagnetism, and quantum theory to more sophisticated views of these subjects and their interdependence. The goal is to guide undergraduates through some of the trickier areas of theoretical physics with concise analysis while revealing the key elegance of each subject. The first chapter introduces the key areas of the principle of least action, an alternative treatment of Newtownian dynamics, that provides new understanding of conservation laws. In particular, it shows how the formalism evolved from Fermat's principle of least time in optics. The second introduces special relativity leading quickly to the need and form of four-vectors. It develops four-vectors for all kinematic variables and generalize Newton's second law to the relativistic environment; then returns to the principle of least action for a free relativistic particle. The third chapter presents a review of the integral and differential forms of Maxwell's equations before massaging them to four-vector form so that the Lorentz boost properties of electric and magnetic fields are transparent. Again, it then returns to the action principle to formulate minimal substitution for an electrically charged particle.

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The new field of physical biology fuses biology and physics. New technologies have allowed researchers to observe the inner workings of the living cell, one cell at a time. With an abundance of new data collected on individual cells, including observations of individual molecules and their interactions, researchers are developing a quantitative, physics-based understanding of life at the molecular level. They are building detailed models of how cells use molecular circuits to gather and process information, signal to each other, manage noise and variability, and adapt to their environment. This book narrows down the scope of physical biology by focusing on the microbial cell. It explores the physical phenomena of noise, feedback, and variability that arise in the cellular information-processing circuits used by bacteria. It looks at the microbe from a physics perspective, to ask how the cell optimizes its function to live within the constraints of physics. It introduces a physical and information based – as opposed to microbiological – perspective on communication and signaling between microbes. The book is aimed at non-expert scientists who wish to understand some of the most important emerging themes of physical biology, and to see how they help us to understand the most basic forms of life.

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Creating Materials with a Desired Refraction Coefficient' provides a recipe for creating materials with a desired refraction coefficient, and the many-body wave scattering problem for many small impedance bodies is solved. The physical assumptions make the multiple scattering effects essential. On the basis of this theory, a recipe for creating materials with a desired refraction coefficient is given. Technological problems are formulated which, when solved, make the theory practically applicable. The Importance of a problem of producing a small particle with a desired boundary impedance is emphasized, and inverse scattering with non-over-determined scattering data is considered.

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Musical Sound, Instruments, and Equipment' offers a basic understanding of sound, musical instruments and music equipment, geared towards a general audience and non-science majors. The book begins with an introduction of the fundamental properties of sound waves, and the perception of the characteristics of sound. The relation between intensity and loudness, and the relation between frequency and pitch are discussed. The basics of propagation of sound waves, and the interaction of sound waves with objects and structures of various sizes are introduced. Standing waves, harmonics and resonance are explained in simple terms, using graphics that provide a visual understanding.

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