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.

/pdf/the-atmospheric-pressure-plasma-jet-a-review-and-comparison-4n3xn1jiyb.pdf

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

Atmospheric pressure plasmas: A review

Powders, wires, or cords are the key components on which the quality of the coating obtained using thermal spray strongly depends. As discussed throughout this book, Thermal Spray Technology centers around the use of mechanical, chemical, or electrical energy to develop a high energy gas stream in which the material to be sprayed is injected in the form of a powder, wire, cord, suspension, or solution. On contact with the high energy spraying medium which transforms the injected material into a high energy spray of individual particles or molten droplets that are entrained by the process gas and projected against the substrate forming splats. The coating is formed through the layering of these splats with strong adhesion to the surface of the substrate and the required microstructure for its functional role whether it is for wear or corrosion protection, thermal protection, or any of other functional properties.

Powders, Wires, and Cords

Summary form only given. The quantitative description of an electric arc which is exposed to a cold gas flow from a direction perpendicular to the arc axis poses several difficulties. The major one is the need for a fully three dimensional treatment and the lack of symmetry at the boundaries. We present a theoretical treatment of such an arc with the development of a computer code for solving the three dimensional conservation equations. Validation of this code has been performed by obtaining computational results for conditions for which experimental data exist. The calculations yield temperature and velocity fields and distributions of current density and potential. Results are presented for conditions encountered in the application of a wire arc spray process: an arc current of 100 and 200 A and an arcing gap of 1 mm and 2 mm, and a configuration where the electrodes are sections of a nozzle. The plasma gas has been argon, and a range of cross flow velocities has been investigated. The results show that the location of highest temperature is downstream of the location of highest electric field and highest power dissipation because of the asymmetric energy transport. The anode attachment is less constricted and farther downstream than the cathode attachment, however the flow turbulence essentially eliminates the differences in the temperatures and velocities caused by the difference in electrode attachments a short distance downstream. This code can be used to illustrate the influence of the physical parameters in processes where arcs in cross flow are encountered.

Physics of an arc in cross-flow

La presente invention concerne des lots de particules a base de phosphore ayant une taille particulaire moyenne inferieure a environ 200 nm et un rendement quantique interne moyen d'au moins 40 %. Les lots de particules a base de phosphore de taille nanometrique peuvent etre essentiellement exempts d'impuretes. L'invention decrit egalement des procedes de fabrication des particules a base de phosphore de taille nanometrique en faisant passer les particules a base de phosphore a travers un champ reactif afin de les dissocier ainsi en des elements et ensuite en synthetisant les particules a base de phosphore de taille nanometrique en faisant germer les elements et en trempant les particules resultantes.

Particules à base de phosphore de taille nanométrique ayant un rendement quantique élevé et leur procédé de synthèse

Structure of Atmospheric Pressure Non-equilibrium Plasmas and Application to Advanced Materials Processing Tomohiro NOZAKI*1, Ken OKAZAKI*1, Joachim HEBERLEIN*2 and Uwe KORTSHAGEN*2 *1Department of Mechanical and Control Engineering , Tokyo Institute of Technology 2-12-1 O-okayama Meguro, 1528552 Tokyo Japan *2University of Minnesota , Department of Mechanical Engineering 111 Church St Minneapolis, MN 55455 USA

Structure of Atmospheric Pressure Non-equilibrium Plasmas and Application to Advanced Materials Processing

Summary form only given. Metallic vapor emanating from the electrodes and plastic vapor from wall ablation on or before current-zero in a low-voltage circuit breaker (LVCB) significantly affect the dielectric recovery characteristics of atmospheric pressure air in the contact gap after current-zero. When the net ionization coefficient becomes positive, dielectric breakdown is said to occur and the reduced electric field (E/N) of this occurrence is termed the critical reduced electric field ((E/N)crit) [1]. In this paper, we analyze the dielectric breakdown behavior for the case of copper being the electrode material and polyamide 6/6 (PA-66) being the plastic wall material. Firstly, the chemical composition is calculated by the minimization of Gibbs free energy and the results are compared for two different methodologies (denoted as M1 [2] and M2 [3], for convenience). Unlike M2, M1 includes the condensed species of copper and carbon (graphite) and it will be shown that below 3500 K, the two methods provide widely different composition results. Secondly, Boltzmann's EEDF equation is solved to obtain the generalized non-Maxwellian electron-energy distribution function (EEDF) [4], with the electron-impact collision cross-sections gathered from literature as input. Using the afore-mentioned inputs, (E/N)crit is calculated and plotted against temperature ranging between 300-6000 K, for different mass-fraction values of air, copper and PA-66. Additionally, it has been observed that the presence of vibrationally- and electronically-excited species enhances the dielectric breakdown by lowering (E/N)crit. This approach is part of an initial attempt towards addressing realistic chemical non-equilibrium conditions involving finite-rate kinetics in an LVCB after current-zero and the numerical results will subsequently be utilized for comparisons with available experimental data.

Chemical equilibrium composition of air-copper-PA66 mixtures and their effects on dielectric breakdown for low-voltage circuit breaker post-current-zero

Joachim Heberlein

Papers

Powders, Wires, and Cords

Physics of an arc in cross-flow

Particules à base de phosphore de taille nanométrique ayant un rendement quantique élevé et leur procédé de synthèse

Structure of Atmospheric Pressure Non-equilibrium Plasmas and Application to Advanced Materials Processing

Chemical equilibrium composition of air-copper-PA66 mixtures and their effects on dielectric breakdown for low-voltage circuit breaker post-current-zero