This book explores statistical physics, with an emphasis on the distinct character of the statistical motion and difficult subjects, related, mainly, to condensed matter. It discusses the interaction ...problem in real gases, as well as dimensionality effects and melting. The book shows how to estimate easily the critical temperature of the Ising ferromagnets, the origin of the drag force, how to get an inverse-wind vortex in turbulence, the entropy of the earthquakes, and how the gas-liquid transition occurs. It also describes the hadronization of the quark-gluon plasma, the phase diagram of the quantum chromodynamics, and the thermodynamics of black holes.
The differential equations of mathematical physics have a twofold character: their physical content and their mathematical solutions. This book discusses the basic tools of theoretical physicists, ...applied mathematicians, and engineers, providing detailed insights into linear algebra, Fourier transforms, special functions, Laplace and Poisson, diffusion and vector equations. These basic tools are a set of methods and techniques, known as the equations of mathematical physics. At first sight, they look like a collection of disparate things. Many students in theoretical physics perceive them as strange, autonomous, inflexible, and ultimately unknown objects, whose sole use resides in their being applied to solving usually standard physical problems.
This book is devoted to a quasi-classical treatment of quantum transitions, with an emphasis on nuclear magnetic resonance, nuclear quadrupole resonance and electric dipolar resonance. The method ...described here is based on the quasi-classical description of condensed matter, and makes use of the equation of motion of harmonic oscillators with external forces. In addition to known results in magnetic resonance, the book also presents parametric resonance for electric dipoles and dipolar interaction which may lead to spontaneous electric polarization.
This book presents the subject of physical kinetics from an original and unique angle, by deriving the Boltzmann equation from atomic motion, making extensive use of Landau's concept of elementary ...excitations. It includes external forces, besides statistical motion, in its treatment of the subject wherever relevant. It also details the kinetic theory of classical gas and its transport, devoting special attention to the classical plasma. In addition, the book emphasises the role played by the anharmonic interactions in the lifetime of phonons, and presents the basic features of superconductivity and superfluidity.
It is shown that the Reynolds equations for a turbulent flow over an unbounded flat surface in the presence of a constant pressure-gradient lead to a displaced logarithmic profile of the velocity ...distribution; the displaced logarithmic profile is obtained by assuming a constant production rate of turbulence energy. The displacement height measured on the (vertical) axis perpendicular to the surface is either positive or negative. For a positive displacement height the boundary layer exhibits an inversion, while for a negative displacement height the boundary layer is a direct one. In an inversion boundary layer the logarithmic velocity profile is disrupted into two distinct branches separated by a logarithmic singularity. The viscosity transforms this logarithmic singularity into a sharp edge, governed by a generalized Reynolds number. The associated temperature distribution is calculated, and the results are discussed in relation to meteorological boundary-layer jets and stratified layers. The effects of gravitation and atmospheric thermal or fluid-mixture concentration gradients (“external forcings”) are also considered; it is shown that such circumstances may lead to various modifications of the boundary layers. A brief presentation of a similar situation is described for a circular pipe.
•The Reynolds equations are employed for turbulent boundary layers.•The conservation equation for the turbulence energy is established.•The equations are solved for a constant production rate of turbulence energy.•A displaced logarithmic law is obtained for the velocity profile.•This law points out an inversion boundary layer.
The deformation and wear behavior of four high strength wear resistant steels were studied in various impact conditions to evaluate their performance in applications involving heavy impacts and ...impact–abrasion. In the normal direction impacts, the studies were conducted with single and repeated (multiple) drop tests. To better simulate the actual application conditions, the samples were positioned at an angle relative to the impact direction in the tests with the high velocity particle impactor (HVPI) device. The effect of strain rate was investigated using constant size projectiles made from materials with different density but keeping the impact energy constant by varying the incident projectile velocity. The effect of surface hardening on the wear resistance of the high strength steels was determined by impacting the same surface area multiple times at a constant velocity using spherical high velocity projectiles. Regardless of the rather similar hardness of the studied three martensitic steel grades, the impact behavior showed differences in wear rate and damage mechanisms in each case due to the microstructural characteristics of the materials. The adiabatic shear bands forming in the martensitic steels at higher loading rates were found to increase the wear rate. Moreover, the carbide reinforced steel performed in general better than the martensitic grades but showed more brittle behavior and generation of crack networks that can affect the wear performance of the material.
•Deformation and wear behavior of high strength steels depends on the impact conditions.•Microstructural features affect the impact behavior more than the initial hardness.•Adiabatic shear bands increase the impact wear of auto-tempered martensitic steels.
Surface engineering shows an increasing potential to provide a sustainable approach to icing problems. Currently, several passive anti-ice properties adoptable to coatings are known, but further ...research is required to proceed for practical applications. This is due to the fact that icing reduces safety, operational tempo, productivity and reliability of logistics, industry and infrastructure. An icing wind tunnel and a centrifugal ice adhesion test equipment can be used to evaluate and develop anti-icing and icephobic coatings for a potential use in various arctic environments, e.g., in wind power generation, oil drilling, mining and logistic industries. The present study deals with evaluation of icing properties of flame-sprayed polyethylene (PE)-based polymer coatings. In the laboratory-scale icing tests, thermally sprayed polymer coatings showed low ice adhesion compared with metals such as aluminum and stainless steel. The ice adhesion strength of the flame-sprayed PE coating was found to have approximately seven times lower ice adhesion values compared with metallic aluminum, indicating a very promising anti-icing behavior.
The alloying of Hadfield steels aims at enhanced mechanical properties and improvements in the wear resistance. In this work, the impact and abrasive properties of a chromium-alloyed high-manganese ...Hadfield steel were experimentally studied using a wide variety of testing techniques and characterization methods. In addition, an in-service sample was characterized to identify the wear and hardening mechanisms in a real application (jaw crusher). The dynamic mechanical behavior of the steel was determined using the Hopkinson split bar technique. The abrasion properties were studied with three-body abrasion tests using several different natural abrasives. The effects of existing plastic strain and normal loading on the surface hardening and wear rate were further investigated with scratch testing. High-velocity impact testing was performed to evaluate the effect of pre-strain on the impact wear behavior of the material. It was shown that the dynamic loading affects both the yield behavior and the strain hardening rate of the studied steel. The connection between pre-strain, hardness, and wear rate in abrasion was established. In impact conditions, plastic straining of the surface layer first has a positive effect on the wear resistance, but when strain hardening reached the observed ductility limit, it showed an adverse effect on the material’s performance. The addition of chromium and an increase in the manganese content from the nominal ASTM Hadfield composition provided some improvements in the strength, ductility, and surface hardening of the studied steel.
In certain conditions a macroscopic quantum-mechanical scattering may occur, which may lead to a coherent cross-section on a macroscopic scale in a monocrystal. The conditions are satisfied by ...neutrinos, but not satisfied by other projectiles, with a higher cross-section. This may explain Weber-type experiments of neutrino detection by a perfect, stiff sapphire monocrystal. The occurrence of coherence domains for quantum-mechanical scattering and classical diffraction is analyzed, and the force exerted upon a macroscopic target is estimated. It is concluded that neutrinos exhibit a distinctive feature in this respect, due precisely to their very small cross-section.
