Valery Sheverev - Academia.edu (original) (raw)
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Papers by Valery Sheverev
Aiaa Journal, May 2, 2012
... Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). (1) Polytechnic University, Broo... more ... Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). (1) Polytechnic University, Brooklyn, New York 11201, ETATS-UNIS (2) Ganesh Raman Illinois Institute of Technology, Chicago, Illinois 60616, RUSSIE, FEDERATION DE (3) Vladimir Soukhomlinov Saint ... Onda choque. ; ...
Physical Review E Statistical Nonlinear and Soft Matter Physics, May 1, 2005
Chemi-ionization by two mercury atoms to produce mercury atomic and molecular ions has been consi... more Chemi-ionization by two mercury atoms to produce mercury atomic and molecular ions has been considered an important process in fluorescent lamps (FLs) for a quarter of a century. Despite the absence of reliable data, these processes have been included in a number of numerical models to help explain some of the experimental observations. These models have shown that the most important process is the Penning ionization of two Hg metastable atoms Hg(6 3P2 )+Hg(6 3P2 )→ Hg+ +Hg(6 1S0 )+e . Although there is no experimental measurement of this cross section, modelers have typically used values implied from measurements of other chemi-ionization cross sections, or values obtained by fitting parameters to numerical models to obtain agreement with experiment. Recent theoretical investigations have indicated that the cross sections for the important processes may not be as large as previously thought. The aim of the present paper is to critically review the historical development of studies of chemi-ionization in fluorescent lamps and to present new experimental evidence which is consistent with the theoretical calculations and contradicts the conclusions from previously published experiments.
Chemi-ionization processes resulting from the interaction of two excited Hg atoms have been widel... more Chemi-ionization processes resulting from the interaction of two excited Hg atoms have been widely used in numerical models of fluorescent lamp discharges. In particular, the Penning process Hg (6p 3^{3} 3 P $ _ {2}) +Hg(6p+ Hg (6p +Hg(6p^{3} $ P $ _ {2})\ quad\ to $ Hg $^{+} ...
Transactions of the American Nuclear Society
ABSTRACT
Admixtures to helium of 100 and 5 ppm of nitrogen, and 100 and 10 ppm of carbon monoxide were ide... more Admixtures to helium of 100 and 5 ppm of nitrogen, and 100 and 10 ppm of carbon monoxide were identified and measured in the helium discharge afterglow using an electrical probe placed into the plasma. For nitrogen and carbon monoxide gases, the measured electron energy spectra display distinct characteristic peaks (fingerprints). Location of the peaks on the energy scale is determined by the ionization energies of the analyte molecules. Nitrogen and carbon monoxide fingerprints were also observed in a binary mixture of these gases in helium, and the relative concentration of analytes has been predicted. The technically simple and durable method is considered a good candidate for a number of analytical applications, and in particular, in GC and for analytical flight instrumentation.
44th AIAA Aerospace Sciences Meeting and Exhibit, 2006
This paper discusses a novel micro-optical force sensor based on dielectric microspheres that are... more This paper discusses a novel micro-optical force sensor based on dielectric microspheres that are excited by coupling light from optical fibers. The technique exploits the morphology-dependent shifts in resonant frequencies that are commonly referred to as the whispering gallery modes (WGM). A small change in the size, shape or optical constants of the microsphere causes a shift in the resonant
45th AIAA Aerospace Sciences Meeting and Exhibit, 2007
In this paper, we investigate the performance of a prototype micro-optical force sensor and discu... more In this paper, we investigate the performance of a prototype micro-optical force sensor and discuss issues related to its sensitivity and calibration. The measurement concept is based on the shifts in the optical resonances of small dielectric spheres. The optical resonances, commonly referred to as the whispering gallery modes (WGM), are excited by evanescently coupling light from a tunable diode laser using a tapered single mode fiber. The spheres are of the order of several hundred microns in diameter. The WGMs of the spheres are observed as sharp dips in the transmission spectrum through the fiber. A compressive force applied to the sphere induces a change in both the shape and the index of refraction of the sphere. These changes, in turn, lead to a shift in the optical resonance (WGM). We built and analyzed the performance of micro -sensor prototypes using silica and polymer (Polymethyl- Methacrylate or PMMA) dielectric spheres. In the case of PMMA, we used both solid and hollow spheres as sensor. The solid silica and hollow PMMA sensors offer the lowest and highest measurements sensitivity, respectively. The silica sensors have the largest force range. As expected, smaller sensor sizes lead to increased sensitivity.
8th AIAA/CEAS Aeroacoustics Conference & Exhibit, 2002
International Journal of Aeroacoustics, 2007
ABSTRACT Sound propagation through regions of non-uniform temperature distribution in a gas is st... more ABSTRACT Sound propagation through regions of non-uniform temperature distribution in a gas is studied numerically. The main objective of this study is to determine the impact of temperature gradients on the sound wave parameters and to evaluate the effectiveness of using ...
42nd AIAA Aerospace Sciences Meeting and Exhibit, 2004
Sound wave propagation through regions of non-uniform temperature distribution in a gas is studie... more Sound wave propagation through regions of non-uniform temperature distribution in a gas is studied numerically. The main objective of this study is to determine the impact of temperature gradients on the sound wave parameters and to evaluate the effectiveness of using glow ...
42nd AIAA Aerospace Sciences Meeting and Exhibit, 2004
1st Flow Control Conference, 2002
Aiaa Journal, May 2, 2012
... Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). (1) Polytechnic University, Broo... more ... Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). (1) Polytechnic University, Brooklyn, New York 11201, ETATS-UNIS (2) Ganesh Raman Illinois Institute of Technology, Chicago, Illinois 60616, RUSSIE, FEDERATION DE (3) Vladimir Soukhomlinov Saint ... Onda choque. ; ...
Physical Review E Statistical Nonlinear and Soft Matter Physics, May 1, 2005
Chemi-ionization by two mercury atoms to produce mercury atomic and molecular ions has been consi... more Chemi-ionization by two mercury atoms to produce mercury atomic and molecular ions has been considered an important process in fluorescent lamps (FLs) for a quarter of a century. Despite the absence of reliable data, these processes have been included in a number of numerical models to help explain some of the experimental observations. These models have shown that the most important process is the Penning ionization of two Hg metastable atoms Hg(6 3P2 )+Hg(6 3P2 )→ Hg+ +Hg(6 1S0 )+e . Although there is no experimental measurement of this cross section, modelers have typically used values implied from measurements of other chemi-ionization cross sections, or values obtained by fitting parameters to numerical models to obtain agreement with experiment. Recent theoretical investigations have indicated that the cross sections for the important processes may not be as large as previously thought. The aim of the present paper is to critically review the historical development of studies of chemi-ionization in fluorescent lamps and to present new experimental evidence which is consistent with the theoretical calculations and contradicts the conclusions from previously published experiments.
Chemi-ionization processes resulting from the interaction of two excited Hg atoms have been widel... more Chemi-ionization processes resulting from the interaction of two excited Hg atoms have been widely used in numerical models of fluorescent lamp discharges. In particular, the Penning process Hg (6p 3^{3} 3 P $ _ {2}) +Hg(6p+ Hg (6p +Hg(6p^{3} $ P $ _ {2})\ quad\ to $ Hg $^{+} ...
Transactions of the American Nuclear Society
ABSTRACT
Admixtures to helium of 100 and 5 ppm of nitrogen, and 100 and 10 ppm of carbon monoxide were ide... more Admixtures to helium of 100 and 5 ppm of nitrogen, and 100 and 10 ppm of carbon monoxide were identified and measured in the helium discharge afterglow using an electrical probe placed into the plasma. For nitrogen and carbon monoxide gases, the measured electron energy spectra display distinct characteristic peaks (fingerprints). Location of the peaks on the energy scale is determined by the ionization energies of the analyte molecules. Nitrogen and carbon monoxide fingerprints were also observed in a binary mixture of these gases in helium, and the relative concentration of analytes has been predicted. The technically simple and durable method is considered a good candidate for a number of analytical applications, and in particular, in GC and for analytical flight instrumentation.
44th AIAA Aerospace Sciences Meeting and Exhibit, 2006
This paper discusses a novel micro-optical force sensor based on dielectric microspheres that are... more This paper discusses a novel micro-optical force sensor based on dielectric microspheres that are excited by coupling light from optical fibers. The technique exploits the morphology-dependent shifts in resonant frequencies that are commonly referred to as the whispering gallery modes (WGM). A small change in the size, shape or optical constants of the microsphere causes a shift in the resonant
45th AIAA Aerospace Sciences Meeting and Exhibit, 2007
In this paper, we investigate the performance of a prototype micro-optical force sensor and discu... more In this paper, we investigate the performance of a prototype micro-optical force sensor and discuss issues related to its sensitivity and calibration. The measurement concept is based on the shifts in the optical resonances of small dielectric spheres. The optical resonances, commonly referred to as the whispering gallery modes (WGM), are excited by evanescently coupling light from a tunable diode laser using a tapered single mode fiber. The spheres are of the order of several hundred microns in diameter. The WGMs of the spheres are observed as sharp dips in the transmission spectrum through the fiber. A compressive force applied to the sphere induces a change in both the shape and the index of refraction of the sphere. These changes, in turn, lead to a shift in the optical resonance (WGM). We built and analyzed the performance of micro -sensor prototypes using silica and polymer (Polymethyl- Methacrylate or PMMA) dielectric spheres. In the case of PMMA, we used both solid and hollow spheres as sensor. The solid silica and hollow PMMA sensors offer the lowest and highest measurements sensitivity, respectively. The silica sensors have the largest force range. As expected, smaller sensor sizes lead to increased sensitivity.
8th AIAA/CEAS Aeroacoustics Conference & Exhibit, 2002
International Journal of Aeroacoustics, 2007
ABSTRACT Sound propagation through regions of non-uniform temperature distribution in a gas is st... more ABSTRACT Sound propagation through regions of non-uniform temperature distribution in a gas is studied numerically. The main objective of this study is to determine the impact of temperature gradients on the sound wave parameters and to evaluate the effectiveness of using ...
42nd AIAA Aerospace Sciences Meeting and Exhibit, 2004
Sound wave propagation through regions of non-uniform temperature distribution in a gas is studie... more Sound wave propagation through regions of non-uniform temperature distribution in a gas is studied numerically. The main objective of this study is to determine the impact of temperature gradients on the sound wave parameters and to evaluate the effectiveness of using glow ...
42nd AIAA Aerospace Sciences Meeting and Exhibit, 2004
1st Flow Control Conference, 2002