Download or read book Cavitation Bubble Nucleation by Energetic Particles written by and published by . This book was released on 1998 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the early sixties, experimental measurements using a bubble chamber confirmed quantitatively the thermal spike theory of bubble nucleation by energetic particles: the energy of the slow, heavy alpha decay recoils used in those experiments matched the calculated bubble nucleation energy to within a few percent. It was a triumph, but was soon to be followed by a puzzle. Within a couple of years, experiments on similar liquids, but well below their normal boiling points, placed under tensile stress showed that the calculated bubble nucleation energy was an order of magnitude less than the recoil energy. Why should the theory work so well in the one case and so badly in the other? How did the liquid, or the recoil particle, "know" the difference between the two experiments? Another mathematical model of the same physical process, introduced in 1967, showed qualitatively why different analyses would be needed for liquids with high and low vapor pressures under positive or negative pressures. But, the quantitative agreement between the calculated nucleation energy and the recoil energy was still poor--the former being smaller by a factor of two to three. In this report, the 1967 analysis is extended and refined: the qualitative understanding of the difference between positive and negative pressure nucleation, "boiling" and "cavitation" respectively, is retained, and agreement between the negative pressure calculated to be needed for nucleation and the energy calculated to be available is much improved. A plot of the calculated negative pressure needed to induce bubble formation against the measured value now has a slope of 1.0, although there is still considerable scatter in the individual points.
Download or read book Cavitation Nucleation by Energetic Particles written by C. West and published by . This book was released on 1967 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cavitation in a Mercury Target written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent theoretical work on the formation of bubble nucleation centers by energetic particles leads to some reasonably credible calculations of the maximum negative pressure that might be sustained without bubble formation in the mercury target of the Spallation Neutron Source.
Download or read book Bubble Mediated Focused Ultrasound written by Tianming Wu and published by . This book was released on 2007 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Cavitation is often the result of rapid and intense hyperthermia using high-intensity focused ultrasound (HIFU) to treat malignant tumors deep in tissue. With proper parameters, cavitation bubbles are very efficient in transforming acoustic energy into heat. In vivo and in vitro studies have shown that bubble enhanced heating can potentially increase HIFU efficacy. However, sporadic nucleation of bubbles and subsequent nonlinear oscillations allow uncontrolled cavitation to induce irregular lesions and other unpredictable and thus undesirable effects. This work takes a modeling approach to investigate the physical mechanisms necessary for developing bubble-mediated HIFU therapy with a satisfactory degree of predictability and controllability. Controlled nucleation is possible with a transient vapor cavity generated from a laser heated gold nano-particle in combination with proper acoustic conditions. Preliminary experimental studies in optically transparent gel phantoms have been conducted and results show that the combined use of laser, HIFU and nano-particles reduces the cavitation threshold significantly, and the temporal and spatial characteristics of cavitation events can be controlled by the sound-light interaction mediated with the particles. A mathematical model for particle heating, vapor bubble nucleation and the subsequent bubble dynamics is constructed to predict cavitation thresholds of laser and HIFU energy, and results are comparable with experiments. A parametric study is presented to investigate the effects of particle size and laser pulse length for the optimization of this technique to generate cavitation on demand. In another effort, the interactions of acoustic propagation and the thermal effects in the presence of cavitation bubbles (mostly gas) and boiling bubbles (mostly vapor) are modeled. By introducing temperature dependent viscosity, surface tension coefficient and vapor pressure into the nonlinear gas bubble dynamics, the variation of the bubble radial oscillations, size distributions and subsidiary heating due to the temperature elevation are studied. A continuum bubbly medium is constructed with effective sound speed and attenuation derived from the temperature dependent nonlinear gas bubble When boiling occurs, the vapor bubbles are simply modeled as pressure release cavities. An iterative simulation for acoustic, cavitation(boiling) and thermal fields is then constructed to model the lesion developments, with updating time scales estimated from intrinsic space-time scales related to the evolution of bubble clusters observed from experiments. Results indicate that cavitation enhances ultrasonic absorption and creates larger and wider lesions in a shorter time. The scattering due to the impedance mismatch in the cavitation zone is responsible for the irregular lesions. The heating from cavitation bubbles also accelerates the emerging of vapor bubbles and boiling. The current scheme has exhibited its effectiveness in predicting the position, shape and size of an evolving lesion during bubble-mediated HIFU therapy, given the thermal and acoustical properties of the target tissue and the ultrasonic insonation parameters such as focal intensity and exposure duration.
Download or read book Cavitation and Bubble Dynamics written by Christopher E. Brennen and published by Cambridge University Press. This book was released on 2014 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cavitation and Bubble Dynamics deals with fundamental physical processes of bubble dynamics and cavitation for graduate students and researchers.
Download or read book Cavitation in Biomedicine written by Mingxi Wan and published by Springer. This book was released on 2015-08-29 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a systematic introduction to the engineering principles and techniques of cavitation in biomedicine on the basis of its physics and mechanism. Adopting an interdisciplinary approach, it covers areas of interest ranging from physics and engineering to the biological and medical sciences. Individual chapters introduce the fundamentals of cavitation, describe its characterization, control and imaging techniques, and present cavitation-enhanced thermal and mechanical effects and their applications. Intended as both a reference work for graduate students, and as a guide for scientists and engineers who work with cavitation in biomedicine, it provides a broad and solid foundation of knowledge. The aim is to bridge the different disciplines involved, and to promote cross-discipline research, thus encouraging innovations in the scientific research and engineering applications alike. Dr. Mingxi Wan is a professor at Department of Biomedical Engineering, Xi’an Jiao Tong University, Xi’an, Shaanxi, China; Dr. Yi Feng works at Department of Biomedical Engineering, Xi’an Jiao Tong University, Xi’an, Shaanxi, China; Dr. Gail ter Haar is a professor at The Institute of Cancer Research, Sutton, Surry, UK.
Download or read book Energy Aspects of Acoustic Cavitation and Sonochemistry written by Oualid Hamdaoui and published by Elsevier. This book was released on 2022-08-06 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energy Aspects of Acoustic Cavitation and Sonochemistry: Fundamentals and Engineering covers topics ranging from fundamental modeling to up-scaled experiments. The book relates acoustic cavitation and its intrinsic energy balance to macroscopic physical and chemical events that are analyzed from an energetic perspective. Outcomes are directly projected into practical applications and technological assessments covering energy consumption, thermal dissipation, and energy efficiency of a diverse set of applications in mixed phase synthesis, environmental remediation and materials chemistry. Special interest is dedicated to the sonochemical production of hydrogen and its energetic dimensions. Due to the sensitive energy balance that governs this process, this is seen as a "green process" for the production of future energy carriers. - Provides a concise and detailed description of energy conversion and exchange within the single acoustic cavitation bubble and bubble population, accompanying physical and chemical effects - Features a comprehensive approach that is supported by experiments and the modeling of energy concentration within the sonochemical reactor, jointly with energy dissipation and damping phenomenon - Gives a clear definition of energy efficiency metrics of industrial sono-processes and their application to the main emergent industrial fields harnessing acoustic cavitation and sonochemistry, notably for the production of hydrogen
Download or read book Nucleation of Water written by Ari Laaksonen and published by Elsevier. This book was released on 2021-11-25 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleation of Water: From Fundamental Science to Atmospheric and Additional Applications provides a comprehensive accounting of the current state-of-the-art regarding the nucleation of water. It covers vapor-liquid, liquid-vapor, liquid-ice and vapor-ice transitions and describes basic kinetic and thermodynamic concepts in a manner understandable to researchers working on specific applications. The main focus of the book lies in atmospheric phenomena, but it also describes engineering and biological applications. Bubble nucleation, although not of major atmospheric relevance, is included for completeness. This book presents a single, go-to resource that will help readers understand the breadth and depth of nucleation, both in theory and in real-world examples. - Offers a single, comprehensive work on water nucleation, including cutting- edge research on ice, cloud and bubble nucleation - Written primarily for atmospheric scientists, but it also presents the theories in such a way that researchers in other disciplines will find it useful - Written by one of the world's foremost experts on ice nucleation
Download or read book Sonochemistry Cavitation written by Margulis and published by CRC Press. This book was released on 1995-11-30 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sonochemistry and cavitation are rapidly increasing in importance in modern chemistry as a result of many significant achievements made in recent years. In this current and comprehensive text, the author clearly details and illustrates these developments as well as the fundamental concepts. Much attention is given to the fundamental problems, such as the general kinetics of sonochemical reactions: energetic yields; the principles of the cavitation diffusion theory; the place of acoustic energy among other physical methods of action on matter; and the new electrical theory of cavitation phenomena, sonochemical reactions and sonoluminescence initiation (the theory developed by Professor Margulis). Results of low-frequency acoustic fields investigations are also observed. Special attention is given to the influence of acoustic fields on chemical reactions in nonaqueous systems, catalytic processes and the initiation of oscillating reactions. This publication is designed to broaden the application of ultrasound in chemical technology and improve the efficiency of existing production processes. Its comprehensiveness makes it a practical handbook which will prove invaluable to a broad readership amongst chemistry, engineering and physics undergraduates, graduates, researchers, and industrialists working in the fields of sonochemistry, ultrasonic and chemical technology, high energy chemistry, acoustics and biology.
Download or read book Cavitation and Bubble Dynamics written by Phoevos Koukouvinis and published by Elsevier. This book was released on 2021-09-24 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cavitation and Bubble Dynamics: Fundamentals and Applications examines the latest advances in the field of cavitation and multiphase flows, including associated effects such as material erosion and spray instabilities. This book tackles the challenges of cavitation hindrance in the industrial world, while also drawing on interdisciplinary research to inform academic audiences on the latest advances in the fundamentals. Contributions to the book come from a wide range of specialists in areas including fuel systems, hydropower, marine engineering, multiphase flows and computational fluid mechanics, allowing readers to discover novel interdisciplinary experimentation techniques and research results. This book will be an essential tool for industry professionals and researchers working on applications where cavitation hindrance affects reliability, noise, and vibrations. - Covers a wide range of cavitation and bubble dynamics phenomena, including shock wave emission, jetting, and luminescence - Provides the latest advice about applications including cavitation tunnels, cavitation testing, flow designs to avoid cavitation in pumps and other hydromachinery, and flow lines - Describes novel experimental techniques, such as x-ray imaging and new computational techniques
Download or read book Cavitation written by Sivakumar Manickam and published by CRC Press. This book was released on 2014-08-05 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: As nanomaterials and their end products occupy the pinnacle position of consumer markets, it becomes vital to analyze their generation processes. One of the green chemistry principles underlines the need for unusual energy sources to generate them. Utilizing the extreme energy from the collapse of cavitation bubbles, generated by either ultrasound or hydrodynamic forces, for the generation of nanomaterials is a merit to consider in this "Green Chemical Processing Era." A wide range of nanomaterials have been developed in the past decade using cavitation or coupling cavitation with other techniques such as microwave, photochemistry, and electrochemistry, resulting in nanomaterials with unique morphologies, reduced size, narrow size distribution, and innumerous advantages. While a few currently available books deal with the fundamental aspects of cavitation and sonochemistry, this book is devoted specifically to the technologically important nanomaterials obtained by cavitation.
Download or read book Cavitation in Non Newtonian Fluids written by Emil Brujan and published by Springer Science & Business Media. This book was released on 2010-09-28 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-Newtonian properties on bubble dynamics and cavitation are fundamentally different from those of Newtonian fluids. The most significant effect arises from the dramatic increase in viscosity of polymer solutions in an extensional flow, such as that generated about a spherical bubble during its growth or collapse phase. In addition, many biological fluids, such as blood, synovial fluid, and saliva, have non-Newtonian properties and can display significant viscoelastic behaviour. This monograph elucidates general aspects of bubble dynamics and cavitation in non-Newtonian fluids and applies them to the fields of biomedicine and bioengineering. In addition it presents many examples from the process industries. The field is strongly interdisciplinary and the numerous disciplines involve have and will continue to overlook and reinvent each others’ work. This book helps researchers to think intuitively about the diverse physics of these systems, to attempt to bridge the various communities involved, and to convey the interest, elegance, and variety of physical phenomena that manifest themselves on the micrometer and microsecond scales.
Download or read book Bubble Nucleation and Dynamics written by Ho-young Kwak and published by . This book was released on 2020-04-21 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: For phenomena involving bubble nucleation, the molecular cluster model is used to predict the tensile strength and superheat limit of liquids and the amount of decompression for gaseous bubble nucleation in supersaturated solutions. The book investigates various gaseous bubble nucleation events including the bubble formation in gas-water solutions, CO bubble formation in iron melts, the formation of microcellular foams in polymers, the nucleation of nano-sized H2O bubbles in rhyolite melts, and bubble nucleation in shear flow fields. The book also investigates vaporous bubble nucleation events such as bubble formation on a cavity-free surface and inside a solid nanopore in 3M NaCl solution, superheat limit of liquids, and bubble nucleation near the absolute zero temperature by quantum tunnelling in liquid helium. For bubble dynamics phenomena, a set of homologous solutions of the Navier-Stokes equations for evolving spherical bubbles are used to treat gaseous bubble growth in organic solutions, polymer solutions, and in viscous rhyolitic melts. The growth and collapse of laser-induced vapor bubbles in liquid, and on solid particles is discussed as an example of homologous motion of the spherical object. Sonoluminescence phenomena in water and in sulfuric acid solutions, the pressure and shock wave propagation in bubbly mixtures, the gravitational collapse of Newtonian stars, and the core collapse of supernovas are also treated using these homologous solutions. The motion of a fire-ball generated by a TNT explosion underwater is obtained using a zero gravitational constant in the equation of motion for Newtonian stars.
Download or read book Solidification Processing of Metallic Alloys Under External Fields written by Dmitry G. Eskin and published by Springer. This book was released on 2018-10-09 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the application of external physical fields to the solidification processing of metallic alloys. Leading academics from around the world present comprehensive and critical reviews on state-of-the-art research and discuss possible future directions. Major physical fields, including electromagnetic, electric, acoustic, and thermal, are considered. In addition, the most advanced synchrotron X-ray based real-time and in-situ studies and numerical modeling methodologies are reviewed and discussed, with a special emphasis on their applications to the solidification processes. Throughout, all chapters are illustrated with both historical and very recent research cases, including typical examples of in-situ studies, modeling, and simulation. This book contains essential knowledge and information suitable for a wide audience, from undergraduate and postgraduate students to academics, practicing researchers, and engineers in materials, metallurgy, and manufacturing.
Download or read book Characterization of Cavitation Bubbles and Sonoluminescence written by Rachel Pflieger and published by Springer. This book was released on 2019-01-31 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest research on fundamental aspects of acoustic bubbles, and in particular on various complementary ways to characterize them. It starts with the dynamics of a single bubble under ultrasound, and then addresses few-bubble systems and the formation and development of bubble structures, before briefly reviewing work on isolated bubbles in standing acoustic waves (bubble traps) and multibubble systems where translation and interaction of bubbles play a major role. Further, it explores the interaction of bubbles with objects, and highlights non-spherical bubble dynamics and the respective collapse geometries. It also discusses the important link between bubble dynamics and energy focusing in the bubble, leading to sonochemistry and sonoluminescence. The second chapter focuses on the emission of light by cavitation bubbles at collapse (sonoluminescence) and on the information that can be gained by sonoluminescence (SL) spectroscopy, e.g. the conditions reached inside the bubbles or the nature of the excited species formed. This chapter also includes a section on the use of SL intensity measurement under pulsed ultrasound as an indirect way to estimate bubble size and size distribution. Lastly, since one very important feature of cavitation systems is their sonochemical activity, the final chapter presents chemical characterizations, the care that should be taken in using them, and the possible visualization of chemical activity. It also explores the links between bubble dynamics, SL spectroscopy and sonochemical activity. This book provides a fundamental basis for other books in the Molecular Science: Ultrasound and Sonochemistry series that are more focused on applied aspects of sonochemistry. A basic knowledge of the characterization of cavitation bubbles is indispensable for the optimization of sonochemical processes, and as such the book is useful for specialists (researchers, engineers, PhD students etc.) working in the wide area of ultrasonic processing.
Download or read book Cavitation nucleation by enegetic particles written by C. West and published by . This book was released on 1967 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
