Review on thermal energy storage with phase change: materials, heat transfer analysis and applications

1. Introduction and overview 2. Film stress and substrate curvature 3. Stress in anisotropic and patterned films 4. Delamination and fracture 5. Film buckling, bulging and peeling 6. Dislocation formation in epitaxial systems 7. Dislocation interactions and strain relaxation 8. Equilibrium and stability of surfaces 9. The role of stress in mass transport.

Thin Film Materials: Stress, Defect Formation and Surface Evolution

The application of mass spectrometric techniques to the realtime measurement and characterization of aerosols represents a significant advance in the field of atmospheric science. This review focuses on the aerosol mass spectrometer (AMS), an instrument designed and developed at Aerodyne Research, Inc. (ARI) that is the most widely used thermal vaporization AMS. The AMS uses aerodynamic lens inlet technology together with thermal vaporization and electron-impact mass spectrometry to measure the real-time non-refractory (NR) chemical speciation and mass loading as a function of particle size of fine aerosol particles with aerodynamic diameters between similar to 50 and 1,000 nm. The original AMS utilizes a quadrupole mass spectrometer (Q) with electron impact (EI) ionization and produces ensemble average data of particle properties. Later versions employ time-of-flight (ToF) mass spectrometers and can produce full mass spectral data for single particles. This manuscript presents a detailed discussion of the strengths and limitations of the AMS measurement approach and reviews how the measurements are used to characterize particle properties. Results from selected laboratory experiments and field measurement campaigns are also presented to highlight the different applications of this instrument. Recent instrumental developments, such as the incorporation of softer ionization techniques (vacuum ultraviolet (VUV) photo-ionization, Li(+) ion, and electron attachment) and high-resolution ToF mass spectrometers, that yield more detailed information about the organic aerosol component are also described. (c) 2007 Wiley Periodicals, Inc.

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Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer

Atmospheric-pressure plasmas are used in a variety of materials processes. Traditional sources include transferred arcs, plasma torches, corona discharges, and dielectric barrier discharges. In arcs and torches, the electron and neutral temperatures exceed 3000/spl deg/C and the densities of charge species range from 10/sup 16/-10/sup 19/ cm/sup -3/. Due to the high gas temperature, these plasmas are used primarily in metallurgy. Corona and dielectric barrier discharges produce nonequilibrium plasmas with gas temperatures between 50-400/spl deg/C and densities of charged species typical of weakly ionized gases. However, since these discharges are nonuniform, their use in materials processing is limited. Recently, an atmospheric-pressure plasma jet has been developed, which exhibits many characteristics of a conventional, low-pressure glow discharge. In the jet, the gas temperature ranges from 25-200/spl deg/C, charged-particle densities are 10/sup 11/-10/sup 12/ cm/sup -3/, and reactive species are present in high concentrations, i.e., 10-100 ppm. Since this source may be scaled to treat large areas, it could be used in applications which have been restricted to vacuum. In this paper, the physics and chemistry of the plasma jet and other atmospheric-pressure sources are reviewed.

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The atmospheric-pressure plasma jet: a review and comparison to other plasma sources

Atmospheric pressure plasmas: A review

A thermal plasma process for the synthesis of nanoparticles and their immediate assembly into nanostructured films is discussed. In this process, known as hypersonic plasma particle deposition, a thermal plasma with injected precursors is expanded through a nozzle to nucleate nanoparticles, which are then inertially deposited onto a cooled substrate in vacuum. A lightly consolidated nanostructured film results. Particle and film diagnostics along with images of the plasma flow are used to explain the formation of nanostructured silicon carbide films by this process.

Thermal plasma deposition of nanostructured films

The reattachment process is an essential part of the dynamics of thermal plasma flows. Simulations of the flow inside a direct-current arc plasma torch performed with a two-temperature model produce a reattachment process triggered by local flow instabilities and driven by local high electric fields and electron temperatures. These results indicate that an arc reattachment can occur not only due to a breakdown of the gas surrounding the plasma but also due to the macroscopic characteristics of the flow, and these emphasize the importance of nonlocal thermodynamic equilibrium-based models to properly describe arc dynamics.

The reattachment process in nonequilibrium arc simulations

Advanced phosphor materials such as cerium-doped yttrium aluminum garnet (YAG) are of interest for a variety of applications, including light-emitting diodes. Previous studies have shown that it is difficult to produce the desired YAG phase without ex-situ annealing irrespective of the synthesis technique used. This study focuses on direct synthesis of YAG phosphor particles using an inductively coupled thermal plasma system with a ceramic tube inserted coaxially into the chamber. Numerical modeling indicates that the tube provides a more uniform high-temperature region, without flow recirculation. This is hypothesized to aid in size and phase control through selective particle collection and in-flight annealing. Experiments conducted with the tube-insertion setup indicate that phase and size control of the particles is possible to a certain extent, depending on the size of the tube. Characterization results of the synthesized particles showed that submicron-sized YAG particles are synthesized as the majority phase through the tube-insertion setup.

Joachim Heberlein

Papers

Thermal plasma deposition of nanostructured films

The reattachment process in nonequilibrium arc simulations

Direct Synthesis of Yttrium Aluminum Garnet Particles in an Inductively Coupled Radio-Frequency Plasma System

Adhesion improvement of diamond films on molybdenum rod substrates using metallic powder

Effect of substrate temperature distribution on thermal plasma jet CVD of diamond