Download or read book Studies of Thermal Transport Properties Using Molecular Dynamics Simulation Techniques written by Juraivan Ratanapisit and published by . This book was released on 1999 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomistic Study of Transport Properties at the Nanoscale written by Justin Haskins and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A first approach to engineering problems in nanosized systems requires a thorough understanding of how physical properties change as size decreases from the macroscale. One important class of properties that can be severely affected by such a downward size shift are transport properties - classical mass, momentum and energy transport. Using atomistic simulation techniques, primarily molecular dynamics, and statistical expressions for diffusion, viscosity, and thermal conductivity formulated in terms of atomistic properties, three case studies of transport in important, nanosized systems are investigated, including confined water systems, silicon-germanium nanos- tructures, and carbon nanostructures. In the first study of confined water systems, diffusion and viscosity are of primary interest, as recent experimental studies have shown notably increased rates of diffusion through nano-confined carbon nanotube structures. In this work, a full treatment of the transport properties is provided in both water clusters and water thin films, both having characteristic size scales under 11 nm. The diffusion, viscosity, and thermal conductivity in the nanosized systems are all shown to be significantly different from bulk water systems, with diffusion and thermal transport increasing and viscosity decreasing. For silicon-germanium nanostructures, the thermal transport properties are exclusively considered, with the problem of interest concerning the control of thermal transport through a strict control on the nanostructure. Quantum dot superlattices are shown to be effective structures for controlling the thermal transport properties, the available range of thermal conductivity using these structures being 0.1-160 W/mK. The final study concerns graphene nanostructures, which in terms of thermal transport have some of the highest thermal conductivities of any available materials. Control of thermal transport properties is again of primary importance, with various physical aspects - defects, shape, and size - being probed in graphene, graphene nano ribbons, carbon nanotubes, and fullerenes to determine their influence on transport; overall, these structures yield a large range of thermal transport, 10-2500 W/mK. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149231
Download or read book Nanoscale Energy Transport and Conversion written by Gang Chen and published by Oxford University Press. This book was released on 2005-03-03 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a graduate level textbook in nanoscale heat transfer and energy conversion that can also be used as a reference for researchers in the developing field of nanoengineering. It provides a comprehensive overview of microscale heat transfer, focusing on thermal energy storage and transport. Chen broadens the readership by incorporating results from related disciplines, from the point of view of thermal energy storage and transport, and presents related topics on the transport of electrons, phonons, photons, and molecules. This book is part of the MIT-Pappalardo Series in Mechanical Engineering.
Download or read book Molecular Dynamics Simulation of Thermal Energy Transport Across Material Interfaces written by Tengfei Luo and published by . This book was released on 2009 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Both ab-initio and classical molecular dynamics (MD) were used to study the thermal energy transport phenomena across nano-scale material interfaces. Thermal equilibration in semiconductor ultra-thin layered superlattices was simulated by ab-initio MD with density functional theory (OFT). Equilibrium MD (EMD) and Non-equilibrium MD (NEMD) simulations were performed on Au-SAM (self-assembly monolayer)-Au junctions with alkanedithiols being the SAM molecules. The in-plane thermal conductivities were calculated using EMD with Green-Kubo method. The out-of-plane thermal conductances were calculated in both EMD and NEMD simulations. Au substrate thickness effect, temperature effect, simulated normal pressure effect, molecular chain length effect, molecule coverage effect and molecule-substrate bonding strength effect on thermal conductivity/conductance were studied. Vibration density of states (VDOS) was calculated, and the mechanism of thermal energy transport across the material junctions was analyzed. The calculated thermal conductance at high temperatures agrees well with available experimental data. The temperature dependence of thermal conductance has a similar trend to experimental observations. SAM molecular coverage was found to be important on the interfacial thermal conductance. Analysis of the junction response to a heat pulse showed that the Au-SAM interface resistance was much larger than the substrate and SAM resistances. The results showed that the Au-SAM interface resistance dominated thermal energy transport across the junction The DFT ab-initio method was used to study the bondings of thiols on As-terminated GaAs (001) surfaces. As-S interactions were simulated by the Morse potential, and the parameters were fitted to an energy hypersurface obtained from DFT calculations. NEMD simulations were then performed on GaAs-SAM-GaAs junctions to study thermal energy transport across thiol-GaAs interfaces. NEMD simulations were also carried out to study thermal energy transport across different graphene-polymer interfaces. The results of this study will be useful for the current molecular electronics industry in which thermal dissipation is a critical problem to be resolved. It is concluded that the interfacial resistance is the barrier for thermal transport across molecule-solid junctions. As a result, methods to facilitate thermal transport across the interfaces, such as depositing denser SAM, forming stronger molecule-solid bonds, choosing materials with better vibration coupling, are to be considered in the emerging technology of the manufacturing of molecular electronics.
Download or read book Transport Properties of Dense Fluid Mixtures Using Nonequilibrium Molecular Dynamics Final Report September 15 1987 March 14 1997 written by and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computer Simulation Studies were carried out using the method of equilibrium and nonequilibrium molecular dynamics (NEMD) to examine a wide range of transport processes in both fluids and fluid mixtures. This included testing a wide range of mixing rules for thermal conductivity and viscosity. In addition a method was developed to calculate the internal rotational contributions to thermal conductivity and the accuracy of current methods for predicting these contributions were examined. These comparisons were then used to suggest possible ways of improving these theories. The method of NEMD was also used to examine the critical enhancements of thermal conductivity. Finally, molecular simulations were carried out to study the various transport coefficients of fluids confined by membranes, as well as important transport processes such as osmosis, and reverse osmosis.
Download or read book First Principles based Molecular Modeling of Thermal Transport in Silicon based Nanomaterials written by Yongjin Lee and published by . This book was released on 2014 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: In today's nanotechnology, a critical issue is to gain the ability to control the structure and function of matter with a deeper understanding of the quantitative and qualitative relationship among their synthesis conditions, structures, and properties. Experiments may provide information regarding the behavior of nanomaterials, but their interpretations are often controversial due largely to the difficulty of direct measurement. Hereupon, with the amazing advance in computer technology since the late 20th century, computational modeling in science and engineering is increasingly important particularly in the fields of nanoscience and nanotechnology while it can provide researchers with significant insights into atomic-level interactions in various materials systems and underlying fundamental theories. The ability of engineering thermal conductivity of materials on the nanoscale has become extremely important in various applications including electronics and energy storage/conversion technologies. Due to technical difficulties in experimentally measuring the thermal conductivity of disordered and complex nanostructures, there has been much interest in use of theoretical and computational methods to investigate thermal transport properties nanostructured materials. One computational method that can perform an accurate analysis for the thermal conductivity of new or complex systems is molecular dynamics (MD), due to its capability of predicting the behaviors of atoms in large systems. In this work, we have developed a comprehensive MD-based computational platform capable of predicting and explaining thermal transport in disordered and complex nanostructured materials. The unique features include construction of realistic nanostructures, determination of reliable force fields, and direct simulation of large systems, which are allowed by coupling various state-of-the-art computational methods including quantum mechanics, molecular mechanics, statistical theories, and massively parallel computing. The computational scheme was applied to describe thermal transport in various silicon and carbon-based disordered and nanostructures. First, the effects of defects including vacancy clusters, substitutional dopants, and dopant-defect complexes on the thermal conductivity of bulk crystalline silicon were investigated. Next, we analyzed the factors affecting heat transport in silicon-germanium and ternary silicon-germanium-tin alloys. Lastly, we performed the analysis of heat transport in silicon-based nanostructures such as nanowires and polycrystalline structures.
Download or read book Statistical Mechanics Theory and Molecular Simulation written by Mark Tuckerman and published by OUP Oxford. This book was released on 2010-02-11 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: Complex systems that bridge the traditional disciplines of physics, chemistry, biology, and materials science can be studied at an unprecedented level of detail using increasingly sophisticated theoretical methodology and high-speed computers. The aim of this book is to prepare burgeoning users and developers to become active participants in this exciting and rapidly advancing research area by uniting for the first time, in one monograph, the basic concepts of equilibrium and time-dependent statistical mechanics with the modern techniques used to solve the complex problems that arise in real-world applications. The book contains a detailed review of classical and quantum mechanics, in-depth discussions of the most commonly used ensembles simultaneously with modern computational techniques such as molecular dynamics and Monte Carlo, and important topics including free-energy calculations, linear-response theory, harmonic baths and the generalized Langevin equation, critical phenomena, and advanced conformational sampling methods. Burgeoning users and developers are thus provided firm grounding to become active participants in this exciting and rapidly advancing research area, while experienced practitioners will find the book to be a useful reference tool for the field.
Download or read book Nanoscale Energy Transport and Harvesting written by Zhang Gang and published by CRC Press. This book was released on 2015-02-04 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energy transport and conversion in nanoscale structures is a rapidly expanding area of science. It looks set to make a significant impact on human life and, with numerous commercial developments emerging, will become a major academic topic over the coming years. Owing to the difficulty in experimental measurement, computational simulation has becom
Download or read book Thermal Transport for Applications in Micro Nanomachining written by Basil T. Wong and published by Springer Science & Business Media. This book was released on 2008-07-19 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with an overview of nanomachining, this monograph introduces the relevant concepts from solid-state physics, thermodynamics, and lattice structures. It then covers modeling of thermal transport at the nanoscale and details simulations of different processes relevant to nanomachining. The final chapter summarizes the important points and discusses directions for future work to improve the modeling of nanomachining.
Download or read book Molecular Dynamics written by Lichang Wang and published by BoD – Books on Demand. This book was released on 2012-04-05 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular Dynamics is a two-volume compendium of the ever-growing applications of molecular dynamics simulations to solve a wider range of scientific and engineering challenges. The contents illustrate the rapid progress on molecular dynamics simulations in many fields of science and technology, such as nanotechnology, energy research, and biology, due to the advances of new dynamics theories and the extraordinary power of today's computers. This first book begins with a general description of underlying theories of molecular dynamics simulations and provides extensive coverage of molecular dynamics simulations in nanotechnology and energy. Coverage of this book includes: Recent advances of molecular dynamics theory Formation and evolution of nanoparticles of up to 106 atoms Diffusion and dissociation of gas and liquid molecules on silicon, metal, or metal organic frameworks Conductivity of ionic species in solid oxides Ion solvation in liquid mixtures Nuclear structures
Download or read book Micro and Nano Thermal Transport written by Lin Qiu and published by Academic Press. This book was released on 2022-02-09 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micro and Nano Thermal Transport Research: Characterization, Measurement and Mechanism is a complete and reliable reference on thermal measurement methods and mechanisms of micro and nanoscale materials. The book has a strong focus on applications and simulation, providing clear guidance on how to measure thermal properties in a systematic way. Sections cover the fundamentals of thermal properties before introducing tools to help readers identify and analyze thermal characteristics of these materials. The thermal transport properties are then further explored by means of simulation which reflect the internal mechanisms used to generate such thermal properties. Readers will gain a clear understanding of thermophysical measurement methods and the representative thermal transport characteristics of micro/nanoscale materials with different structures and are guided through a decision-making process to choose the most effective method to master thermal analysis. The book is particularly suitable for those engaged in the design and development of thermal property measurement instruments, as well as researchers of thermal transport at the micro and nanoscale. Includes a variety of measurement methods and thermal transport characteristics of micro and nanoscale materials under different structures Guides the reader through the decision-making process to ensure the best thermal analysis method is selected for their setting Contains experiments and simulations throughout that help apply understanding to practice
Download or read book Two dimensional Materials written by Pramoda Kumar Nayak and published by BoD – Books on Demand. This book was released on 2016-08-31 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are only a few discoveries and new technologies in materials science that have the potential to dramatically alter and revolutionize our material world. Discovery of two-dimensional (2D) materials, the thinnest form of materials to ever occur in nature, is one of them. After isolation of graphene from graphite in 2004, a whole other class of atomically thin materials, dominated by surface effects and showing completely unexpected and extraordinary properties, has been created. This book provides a comprehensive view and state-of-the-art knowledge about 2D materials such as graphene, hexagonal boron nitride (h-BN), transition metal dichalcogenides (TMD) and so on. It consists of 11 chapters contributed by a team of experts in this exciting field and provides latest synthesis techniques of 2D materials, characterization and their potential applications in energy conservation, electronics, optoelectronics and biotechnology.
Download or read book Phonon Transport in Molecular Dynamics Simulations written by Alan J. H. McGaughey and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computer Simulation in Materials Science written by M. Meyer and published by Springer. This book was released on 1991-09-30 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Study Institute, Aussois, France, March 25-April 5, 1991
Download or read book Molecular Dynamics Simulations and Flow Injection Studies of Hydrothermal Fluids written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrothermal fluids near and above the critical point of water have unique and potentially very useful thermophysical properties. At present, the lack of knowledge of supercritical water chemistry hinders implementation of innovative hydrothermal technologies. The development of new experimental methods and application of molecular modeling tools is clearly warranted to provide a better understanding of the complex properties of aqueous systems at elevated temperatures and pressures. The thermodynamic, dielectric and transport properties of hydrothermal fluids are investigated using Molecular Dynamics (MD) simulation and flow injection techniques. The spatial hydration structures and self-diffusion coefficients of phenol, aniline and naphthalene in aqueous infinitely dilute solution are examined from ambient to supercritical conditions by means of MD simulations. It is shown that the solvation shell around aromatic molecules undergoes significant changes along the liquid-vapour coexistence curve and, essentially, disappears at supercritical conditions. The changes in hydration structures are reflected in the values of the self-diffusion coefficients which dramatically increase near the critical point of water. The thermodynamic and dielectric properties of the Simple Point Charge Extended (SPC/E) water model are examined over a broad range of sub- and supercritical states. Accurate thermodynamic and dielectric equations of state (EOS) for the SPC/E water model are presented. The parameterizations provide the most accurate, up-to-date description of the properties of high-temperature SPC/E water, thus enabling for the direct comparison of molecular simulation results with experimental data via the corresponding states principle. The experimental methodology for the study of aqueous fluids at extreme conditions by using the ex situ flow injection technique is presented. The methodology significantly simplifies the technical aspects of flow injection analysis in hydrot.
Download or read book Modeling Interfacial Thermal Transport with Molecular Dynamics written by Spencer Thomas Wyant and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interfacial heat transport is an increasingly determinant factor controlling the dissipation of heat in many modern electronic, optical, and magnetic devices - driven by their continued miniaturization and corresponding increase in interfacial density. Molecular dynamics (MD) simulations are a highly versatile theoretical tool that can be used to predict, understand, and rationalize interfacial heat transport. However, significant improvements are needed to make MD-based methods accurate enough to predict thermal boundary conductance (TBC) values -- the primary quantity characterizing interfacial heat transport -- that are consistent with experimental values. In this work, I investigate ways of improving MD simulations using three example interface systems: Ge-GaAs, Al-Al2O3, and AlN-GaN. First, accurate interatomic potentials are generated for each system using either pure machine-learned interatomic potentials (MLIPs) or a hybrid approach in which MLIPs are combined with a Taylor-expansion potential. Key tradeoffs between these approaches are assessed, with a particular focus on speed, stability and vibrational accuracy. Next, I explored how key choices in the setup and analysis of TBC calculations can affect the comparison to experimental values. From a Landauer perspective, the results show that a 4-probe definition of TBC can exceed the maximum transmission limit, consistent with new experimental measurements of the Ge-GaAs TBC. After, discussing the advantages and disadvantages of using nonequilibrium or equilibrium molecular dynamics (NEMD vs. EMD) to predict TBC, a new protocol is presented that attempts to mitigate the effects of noise by analyzing EMD data in a mode-specific fashion. While providing qualitatively better TBC results, the protocol unfortunately exhibits significant parameter sensitivity, at least with the current data. Using this protocol and the MLIPs developed in this work, I then predict temperature-dependent TBC values for Al-Al2O3 and Ge-GaAs interfaces, and compare them to experimental measurements. For Al-Al2O3, significant effort is made to establish a correspondence between the modelled atomistic structure and the experimental sample, resulting in a plausible O-terminated and Al-terminated structure. Surprisingly, the predicted TBC of these two structures differ significantly, with correspondingly different behavior in their mode-level contributions. Unfortunately, neither set of TBC results exhibit good agreement with experimental measurements, nor do the TBC predictions for Ge-GaAs, which are hypothesized to be impacted by finite-size effects. Finally, an applied case is explored whereby 15N/14N isotopic disorder was introduced in an AlN-GaN interface in an attempt to enhance TBC, motivated by a prior work. Using a lattice-dynamics-based descriptor, it is shown that isotopic disorder does enhance "mode overlap" between different sides of the interface, which in concept can enhance interfacial heat flow. However, by performing NEMD calculations with the accurate MLIP, and paying close attention to how the temperature drop is extracted, the results demonstrate that no TBC enhancement occurs and that rather, TBC deteriorates with the addition of isotopic disorder in AlN-GaN. The significant difference between this result and that of the prior work may be partially attributed to the use of a more accurate potential.
Download or read book Thermal Transport in Low Dimensions written by Stefano Lepri and published by Springer. This book was released on 2016-04-07 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding non-equilibrium properties of classical and quantum many-particle systems is one of the goals of contemporary statistical mechanics. Besides its own interest for the theoretical foundations of irreversible thermodynamics(e.g. of the Fourier's law of heat conduction), this topic is also relevant to develop innovative ideas for nanoscale thermal management with possible future applications to nanotechnologies and effective energetic resources. The first part of the volume (Chapters 1-6) describes the basic models, the phenomenology and the various theoretical approaches to understand heat transport in low-dimensional lattices (1D e 2D). The methods described will include equilibrium and nonequilibrium molecular dynamics simulations, hydrodynamic and kinetic approaches and the solution of stochastic models. The second part (Chapters 7-10) deals with applications to nano and microscale heat transfer, as for instance phononic transport in carbon-based nanomaterials, including the prominent case of nanotubes and graphene. Possible future developments on heat flow control and thermoelectric energy conversion will be outlined. This volume aims at being the first step for graduate students and researchers entering the field as well as a reference for the community of scientists that, from different backgrounds (theoretical physics, mathematics, material sciences and engineering), has grown in the recent years around those themes.
