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Foamability of liquid particle suspensions / Krishna Vijayaraghavan in Industrial & engineering chemistry research, Vol. 48 N° 17 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 8180–8185 Titre : Foamability of liquid particle suspensions : a modeling study Type de document : texte imprimé Auteurs : Krishna Vijayaraghavan, Auteur ; Alex Nikolov, Auteur ; Darsh Wasan, Auteur Année de publication : 2009 Article en page(s) : pp. 8180–8185 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Liquid  particle  suspensions  Foamability  Monte  Carlo  simulations  Integral  equations Résumé : Recent experiments on the foamability of liquid particle suspensions (with a particle size varying from nanometers to micrometers in diameter and in the absence of any surfactants) have shown that the foamability correlates well with the degree of particle coverage at the air−liquid surface. Furthermore, these experiments have also revealed foam inhibition due to the aggregation or clustering of particles in the bulk at high particle concentrations. The present study is aimed at theoretically modeling the observed phenomena. Theoretical analyses based on Monte Carlo simulations and the integral equations of statistical mechanics are used to model the particle aggregation phenomena in the bulk. The radial distribution functions, which show the particle packing density, are analyzed to obtain the effective energy of interaction between the particles. The maximum in foaminess due to the adsorption of particles on the air−liquid surface and clustering of particles in the bulk is explained. The modeling results are in good agreement with the experimental observations on foaminess with small particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801741q [article] Foamability of liquid particle suspensions : a modeling study [texte imprimé] / Krishna Vijayaraghavan, Auteur ; Alex Nikolov, Auteur ; Darsh Wasan, Auteur . - 2009 . - pp. 8180–8185. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 8180–8185 Mots-clés : Liquid  particle  suspensions  Foamability  Monte  Carlo  simulations  Integral  equations Résumé : Recent experiments on the foamability of liquid particle suspensions (with a particle size varying from nanometers to micrometers in diameter and in the absence of any surfactants) have shown that the foamability correlates well with the degree of particle coverage at the air−liquid surface. Furthermore, these experiments have also revealed foam inhibition due to the aggregation or clustering of particles in the bulk at high particle concentrations. The present study is aimed at theoretically modeling the observed phenomena. Theoretical analyses based on Monte Carlo simulations and the integral equations of statistical mechanics are used to model the particle aggregation phenomena in the bulk. The radial distribution functions, which show the particle packing density, are analyzed to obtain the effective energy of interaction between the particles. The maximum in foaminess due to the adsorption of particles on the air−liquid surface and clustering of particles in the bulk is explained. The modeling results are in good agreement with the experimental observations on foaminess with small particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801741q

Ultra-low power control system for maximal energy harvesting from short duration vibrations / Krishna Vijayaraghavan in IEEE Transactions on control systems technology, Vol. 18 N° 2 (Mars 2010) 

Public ISBD [article]  in IEEE Transactions on control systems technology > Vol. 18 N° 2 (Mars 2010) . - pp. 252-266 Titre : Ultra-low power control system for maximal energy harvesting from short duration vibrations Type de document : texte imprimé Auteurs : Krishna Vijayaraghavan, Auteur ; Rajamani, Rajesh, Auteur Année de publication : 2011 Article en page(s) : pp. 252-266 Note générale : Génie Aérospatial Langues : Anglais (eng) Mots-clés : Battery-less  Energy  harvesting  Optimal  vibration  energy  harvesting  Short  duration  vibrations  standalone  sensors  Traffic  sensor  Ultra-low  power  control  systems  Wireless Index. décimale : 629.1 Résumé : With the advent of ultra-low power sensor packages, there is renewed interest in harvesting vibration energy to power them, thus creating a self sustaining battery-less sensor system. The optimal algorithms previously developed in literature to harvest vibration energy are complex and hence require controllers that consume a significant amount of power. The relatively high power requirement combined with the inherent complex design of these algorithms would also limit them to only applications in which sustained vibration energy is available for harvesting. To address these issues, this paper presents new control systems to optimize the amount of energy harvested from short duration vibrations. Only algorithms that can be implemented using simple ultra-low power analog electronic components are considered. The first algorithm termed ??fixed threshold switching??, has been adapted from literature on harvesting energy from sustained vibration. The second and third algorithms are new optimal control algorithms termed ??maximum voltage switching?? and ??switched inductor??, respectively. The three algorithms are theoretically evaluated and compared for a short duration vibration application. The final section of this paper presents experimental results from the implementation of all the three algorithms on a new battery-less wireless traffic sensor. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5169971 [article] Ultra-low power control system for maximal energy harvesting from short duration vibrations [texte imprimé] / Krishna Vijayaraghavan, Auteur ; Rajamani, Rajesh, Auteur . - 2011 . - pp. 252-266. Génie Aérospatial Langues : Anglais (eng) in IEEE Transactions on control systems technology > Vol. 18 N° 2 (Mars 2010) . - pp. 252-266 Mots-clés : Battery-less  Energy  harvesting  Optimal  vibration  energy  harvesting  Short  duration  vibrations  standalone  sensors  Traffic  sensor  Ultra-low  power  control  systems  Wireless Index. décimale : 629.1 Résumé : With the advent of ultra-low power sensor packages, there is renewed interest in harvesting vibration energy to power them, thus creating a self sustaining battery-less sensor system. The optimal algorithms previously developed in literature to harvest vibration energy are complex and hence require controllers that consume a significant amount of power. The relatively high power requirement combined with the inherent complex design of these algorithms would also limit them to only applications in which sustained vibration energy is available for harvesting. To address these issues, this paper presents new control systems to optimize the amount of energy harvested from short duration vibrations. Only algorithms that can be implemented using simple ultra-low power analog electronic components are considered. The first algorithm termed ??fixed threshold switching??, has been adapted from literature on harvesting energy from sustained vibration. The second and third algorithms are new optimal control algorithms termed ??maximum voltage switching?? and ??switched inductor??, respectively. The three algorithms are theoretically evaluated and compared for a short duration vibration application. The final section of this paper presents experimental results from the implementation of all the three algorithms on a new battery-less wireless traffic sensor. DEWEY : 629.1 ISSN : 1063-6536 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5169971