The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Pentti Kettunen - One of the best experts on this subject based on the ideXlab platform.
-
A method for measuring Particle Velocity in thermal spraying
Surface and Coatings Technology, 1994Co-Authors: Shao L. Chen, Pekka Siitonen, Pentti KettunenAbstract:Abstract A mechanical method was established to determine the Particle Velocity in plasma spraying processes based on rotating slotted double cylinders or discs. The Particle Velocity was found to be a function of the mass of Particles penetrating through the slots at different rotating speeds. The results obtained revealed a close agreement with those measured by the laser Doppler anemometry method and scanning confocal Fabry—Perot interferometer. The method provides a simple and accurate way of detecting the Particle Velocity in thermal spray processes. In addition, the method appears to be a low cost way of establishing measurement unit and high endurance in thermal spraying under such adverse conditions. This may lead to a wide application of the method on an industrial scale.
Y. Horie - One of the best experts on this subject based on the ideXlab platform.
-
Particle Velocity dispersion in shock compression of solid mixtures
AIP Conference Proceedings, 1998Co-Authors: K. Yano, Y. HorieAbstract:Two models were considered to investigate the Particle Velocity dispersion in shock compression of solid mixtures: a continuum mixture model and a discrete element dynamics model. Results for Ni/Al and Ti/Teflon mixtures show (i) a qualitative agreement between the two techniques, (ii) a highly non-equilibrium distribution of Particle Velocity dispersion in the Ni/Al mixture, and (iii) Particle Velocity dispersion on the order of 100 m/s for 10∼15 GPa shock waves. A dispersion of this magnitude is thought to be the mechanism responsible for the initiation of chemical reactions in reactive mixtures.
-
A numerical study of shock-induced Particle Velocity dispersion in solid mixtures
Journal of Applied Physics, 1998Co-Authors: K. Yano, Y. HorieAbstract:Shock-induced Particle Velocity dispersion in solid mixtures was numerically investigated using two approaches: discrete element simulation and continuum mixture calculation. Results show (i) a trend-wise agreement between the two models, (ii) nonequilibrium distributions of Particle Velocity dispersion, and (iii) Particle Velocity dispersions of 20–100 m/s for a 10 GPa shock wave in Ni/Al mixtures and 5–70 m/s for a 5 GPa shock wave in Ti/Teflon mixtures. Particle Velocity dispersions of this magnitude are thought to be the driving mechanism for initiation of chemical reactions in reactive solid mixtures.
A. Abdi - One of the best experts on this subject based on the ideXlab platform.
-
a study of characteristics of underwater acoustic Particle Velocity channels measured by acoustic vector sensors
Journal of the Acoustical Society of America, 2017Co-Authors: Erjian Zhang, A. AbdiAbstract:Acoustic vector sensors measure orthogonal components of acoustic Particle Velocity. When used in underwater communication systems, they act as multichannel receivers. One advantage of a vector receiver, compared to an array of spatially-separated scalar receivers such as hydrophones, is its compact size. Some characteristics of Particle Velocity channels are studied theoretically or via simulations (A. Abdi and H. Guo, “Signal correlation modeling in acoustic vector sensor arrays,” IEEE Transactions on Signal Processing, vol. 57, pp. 892-903, 2009; H. Guo, et al., “Delay and Doppler spreads in underwater acoustic Particle Velocity channels,” J. Acoust. Soc. Am., vol. 129, pp. 2015-2025, 2011). In this paper, we use data measured by a vector sensor to study various key characteristics of underwater Particle Velocity channels, including delay spreads, signal-to-noise ratios, and possible correlations among different channels. By inspecting the eigen structure of channel matrices, we also investigate how va...
-
On the capacity of underwater acoustic Particle Velocity communication channels
2012 Oceans, 2012Co-Authors: A. AbdiAbstract:In this paper, the capacity of acoustic Particle Velocity channels is investigated. Closed form expressions are derived that determine maximum data rates in Particle Velocity channels, in terms of mean angle of arrival and angle spread. These expressions are useful for designing communication systems that operate in Particle Velocity channels.
-
capacity and statistics of measured underwater acoustic Particle Velocity channels
Journal of the Acoustical Society of America, 2011Co-Authors: Chen Chen, A. Abdi, Aijun Song, Mohsen Badiey, Paul HurskyAbstract:Acoustic Particle Velocity channels can be used for communication in underwater systems [A. Abdi and H. Guo, IEEE Trans. Wireless Communi. 8, 3326-3329, (2009)]. In this paper, the information (Shannon) capacity of underwater acoustic Particle Velocity channels is studied using measured data. More specifically, the maximum achievable data rates of a compact vector sensor communication receiver and another communication receiver with spatially separated scalar sensors are compared. Some statistics of Particle Velocity channels such as amplitude distribution and power delay profile are investigated using measured data and proper models are suggested as well. The results are useful for design and simulation of vector sensor underwater communication systems in Particle Velocity channels.The work is supported in part by the National Science Foundation (NSF), Grant CCF-0830190.
-
delay and doppler spreads in underwater acoustic Particle Velocity channels
Journal of the Acoustical Society of America, 2011Co-Authors: A. Abdi, Aijun Song, Mohsen BadieyAbstract:Signal processing and communication in acoustic Particle Velocity channels using vector sensors are of interest in the underwater medium. Due to the presence of multiple propagation paths, a mobile receiver collects the signal with different delays and Doppler shifts. This introduces certain delay and Doppler spreads in Particle Velocity channels. In this paper, these channel spreads are characterized using the zero-crossing rates of channel responses in frequency and time domain. Useful expressions for delay and Doppler spreads are derived in terms of the key channel parameters mean angle of arrival and angle spread. These results are needed for design and performance prediction of systems that utilize underwater acoustic Particle Velocity and pressure channels.
-
CISS - Correlations in underwater acoustic Particle Velocity and pressure channels
2009 43rd Annual Conference on Information Sciences and Systems, 2009Co-Authors: A. Abdi, Aijun Song, Mohsen BadieyAbstract:Depending on the angle of arrivals (AOAs) and other channel characteristics, different types of correlation appear among acoustic pressure and acoustic Particle Velocity channels. To have accurate channel models for communication system design, a complete set of correlations are derived in this paper for a vector sensor array. In addition to exact results, accurate yet less complex approximations are derived as well. Based on the exact correlations, delay spread of pressure and Particle Velocity channels are calculated as well.
Jesse Zhu - One of the best experts on this subject based on the ideXlab platform.
-
Scale-up effect of riser reactors: Particle Velocity and flow development
AIChE Journal, 2005Co-Authors: Aijie Yan, Jesse ZhuAbstract:The influence of riser diameter on the axial and radial Particle Velocity profiles and flow development is studied in a 10 m high twin-riser system (76- and 203-mm ID risers). Cross-sectional average Particle Velocity is somewhat lower for the larger riser with a steeper radial Particle Velocity profile. The flow development in the riser center is nearly instant with the Particle Velocity remaining high. There is no significant difference for the two risers in the center region. In the wall region, the flow development is significantly slower and the Particle Velocity of the smaller riser is higher. The flow development slows down in the larger riser. In all locations measured, there was a clear dependency between the local Particle Velocity and solids concentration of both risers. Gas distribution and Particle aggregation are considered the key factors that influence the local hydrodynamics in the twin-riser system. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Shao L. Chen - One of the best experts on this subject based on the ideXlab platform.
-
A method for measuring Particle Velocity in thermal spraying
Surface and Coatings Technology, 1994Co-Authors: Shao L. Chen, Pekka Siitonen, Pentti KettunenAbstract:Abstract A mechanical method was established to determine the Particle Velocity in plasma spraying processes based on rotating slotted double cylinders or discs. The Particle Velocity was found to be a function of the mass of Particles penetrating through the slots at different rotating speeds. The results obtained revealed a close agreement with those measured by the laser Doppler anemometry method and scanning confocal Fabry—Perot interferometer. The method provides a simple and accurate way of detecting the Particle Velocity in thermal spray processes. In addition, the method appears to be a low cost way of establishing measurement unit and high endurance in thermal spraying under such adverse conditions. This may lead to a wide application of the method on an industrial scale.
