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•High-temperature fluidized beds behave differently below/above a critical temperature.•Motions of bubbles control gas–solid flow structure below the critical temperature.•Flow ...dynamics of solids agglomerate control fluidization above the critical temperatures.•Particle structural changes raise interparticle forces greatly at ultra-high temperatures.•Interparticle forces control fluidization behavior at ultra-high temperatures.
Fluidized beds operating at ultra-high temperatures have great application potential for synthesizing essential materials and chemicals, but they are relatively unexplored. This study, for the first time, investigates fluidization characteristics at temperatures up to 1650 °C by measurement and analysis of pressure fluctuations in a laboratory fluidized bed of 30 mm diameter with corundum particles of an average size of 900 μm. Standard statistical and spectral methods are used to analyze pressure fluctuation signals and characterize fluidization behavior based on the effect of temperature on pressure fluctuation parameters, including the probability density function, standard deviation, autocorrelation, power spectra density, amplitude, dominant frequency, and average cycle frequency. The results indicate that, for the coarse corundum particles used in this study, fluidization behavior inverts at a crucial temperature of approximately 1400 °C. Below this temperature, gas–solid flows in the bed are predominantly controlled by gas bubble movements. In this temperature range, periodicity and maximum amplitude decrease and dominant frequency increases with temperature. Above 1400 °C, interparticle forces, such as van der Waals and viscous forces, are significantly strengthened due to changes in the structural and physiochemical properties of solid materials. The greatly enhanced interparticle forces at ultra-high temperatures promote the dominance of microstructured flows over the overall pressure fluctuations, making interparticle forces the controlling factor influencing gas–solid flows in fluidized beds at ultra-high temperatures. These findings provide a better understanding of ultra-high temperature fluidized beds and can promote their research and development for industrial applications.
We describe a quantum particle constrained on a catenoid, employing an effective description of quantum mechanics based on expected values of observables and quantum dispersions. We obtain ...semiclassical trajectories for particles, displaying general features of the quantum behavior; most interestingly, particles present tunneling through the throat of the catenoid, a characteristic having important physical applications.
•We study a quantum particle constrained to the catenoid surface within the semiclassical method of moments.•Corrections to the classical Hamiltonian due to G-momenta induce modifications in the effective dynamics.•Semiclassical trajectories exhibit various behaviors, including particle tunneling through the waist of the catenoid.
This book provides insights into the tight connection between fundamental math and mechanics, the basic grounding of physics. It demonstrates that quantum, classical, and relativistic mechanics, ...historically (and separately) formulated upon an experimental basis, can be regarded as links of a single theoretical chain readily extracted from a simple mathematical medium. It uses mathematical tools to endow formerly abstract entities, such as quantum wave-function and classical action function, with original and clear geometric images, strongly simplifying them. The book comprises the author's lectures, manual texts, typical problems and tests, and many illustrations, and will be of interest to students of all levels majoring in mathematics, physics and advanced engineering programs.
The coastal ocean comprises the semi-enclosed seas on the continental shelf, including estuaries and extending to the shelf break. This region is the focus of many serious concerns, including coastal ...inundation by tides, storm surges or sea level change; fisheries and aquaculture management; water quality; harmful algal blooms; planning of facilities (such as power stations); port development and maintenance; and oil spills. This book addresses modeling and simulation of the transport, evolution and fate of particles (physical and biological) in the coastal ocean. It is the first to summarize the state of the art in this field and direct it toward diverse applications, for example in measuring and monitoring sediment motion, oil spills and larval ecology. This is an invaluable textbook and reference work for advanced students and researchers in oceanography, geophysical fluid dynamics, marine and civil engineering, computational science and environmental science.
A series of experiments has been performed under earth’s gravity to study formation of particle accumulation structures (PAS) in a supercritical flow driven by the combined effects of buoyancy and ...thermocapillary forces. The test flow was created in a non-isothermal cylindrical column (liquid bridge) made of n-decane and heated from above. The objective of the experiment was to answer two major questions: (1) how strong is the influence of the shape of the interface on the process of formation of PAS; (2) what temperature of the ambient air fits better for PAS to occur. Considering these questions, we developed a method based on changing both the volume of the liquid bridge and temperature at the external walls of the experimental chamber to set and to keep constant the shape of the interface and the temperature inside the setup, respectively. The experimental observations are presented in the form of diagrams in the parameters’ space showing ranges of the PAS formation. The findings show that a liquid bridge with an interface as close to the straight cylindrical as possible and surrounded by air at low temperature is the best terrain for PAS formation. The results of the chaos analysis of the recorded temperature time series and their correlation with the obtained diagrams allow for showing that accumulation of particles in coherent structures is possible only in a periodic oscillatory flow characterized by a small value of the translation error not exceeding 0.01. It is demonstrated that presence of either any spectral noise or of several modes with incommensurate frequencies makes formation of a PAS impossible.
A method for the numerical simulation of the dynamics of particles in a rapidly varying viscous flow has been developed and implemented as a software package. The frequency of variations in the fluid ...velocity is assumed to be such that the nonlinear terms in the equations of motion can be neglected in comparison with the nonstationary terms. The hydrodynamic interaction of the particles is taken into account. The velocities of the particles and their trajectories are computed. It is found that the trajectories of the particles depend substantially on the ratio of their radii. In the case of dipole particles in a rapidly varying external magnetic field, the hydrodynamic interaction is shown to prevent the particles from approaching each other under the influence of dipole-dipole interaction forces.
This unprecedented book offers all the details of the mathematical mechanics underlying modern modeling of skeletal muscle contraction. The aim is to provide an integrated vision of mathematics, ...physics, chemistry and biology for this one understanding. The method is to take advantage of latest mathematical technologies — Eilenberg-Mac Lane category theory, Robinson infinitesimal calculus and Kolmogorov probability theory — to explicate Particle Mechanics, The Theory of Substances (categorical thermodynamics), and computer simulation using a diagram-based parallel programming language (stochastic timing machinery). Proofs rely almost entirely on algebraic calculations without set theory. Metaphors and analogies, and distinctions between representational pictures, mental model drawings, and mathematical diagrams are offered.
