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Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
Application Of Optoelectron Converters Of Reflective Type For Automation Of Liquid And Gas Version Test Measuring Units, Yuriy G. Shipulin, Otabek T. Almataev
Application Of Optoelectron Converters Of Reflective Type For Automation Of Liquid And Gas Version Test Measuring Units, Yuriy G. Shipulin, Otabek T. Almataev
Scientific Bulletin. Physical and Mathematical Research
This work is devoted to the use of reflective optoelectronic converters for the automation of liquid and gas calibration flowmeter installations. Liquid and gas calibration flowmeter devices are widely used for verification and certification of various liquid and gas flowmeters and meters. The analysis of the principles of construction of a reflective optoelectronic converter for calibration devices is carried out and the basic principles of their construction are determined. A functional diagram of an experimental automated programmable calibration test setup of flow meters, liquid meters developed on the basis of ROC is presented. High accuracy requirements are imposed on the …
Catalysis Of Stark-Tuned Interactions Between Ultracold Rydberg Atoms, A. L. Win, W. D. Williams, T. J. Carroll, C. I. Sukenik
Catalysis Of Stark-Tuned Interactions Between Ultracold Rydberg Atoms, A. L. Win, W. D. Williams, T. J. Carroll, C. I. Sukenik
Physics Faculty Publications
We have experimentally investigated a catalysis effect in the resonant energy transfer between ultracold 85Rb Rydberg atoms. We studied the time dependence of the process, 34p + 34p → 34s + 35s, and observed an enhancement of 34s state population when 34d state atoms are added. We have also performed numerical model simulations, which are in qualitative agreement with experiment and indicate that the enhancement arises from a redistribution of p-state atoms due to the presence of the d-state atoms.
Thermal Transportability Based Gas Analysis Using Fiber Bragg Grating Sensors, Yuan Chang
Thermal Transportability Based Gas Analysis Using Fiber Bragg Grating Sensors, Yuan Chang
Legacy Theses & Dissertations (2009 - 2024)
Compositional analysis of gases in real time is important for many industries. Traditionally, it was done with online sensors such as thermal conductivity detectors or analytical methods such as gas chromatography. Fiber Bragg grating (FBG) sensors have demonstrated unique advantages in gas sensing. This dissertation focuses on the designing of a thermal modulation system that can properly functionalize FBG sensors, and the building of a sensing system that can perform non-specific gas compositional analysis in real time for pure gases and binary gas mixtures.
Imaging An Aligned Polyatomic Molecule With Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert
Imaging An Aligned Polyatomic Molecule With Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert
Physics Faculty Research & Creative Works
Laser-induced electron diffraction is an evolving tabletop method that aims to image ultrafast structural changes in gas-phase polyatomic molecules with sub-Ångström spatial and femtosecond temporal resolutions. Here we demonstrate the retrieval of multiple bond lengths from a polyatomic molecule by simultaneously measuring the C-C and C-H bond lengths in aligned acetylene. Our approach takes the method beyond the hitherto achieved imaging of simple diatomic molecules and is based on the combination of a 160kHz mid-infrared few-cycle laser source with full three-dimensional electron-ion coincidence detection. Our technique provides an accessible and robust route towards imaging ultrafast processes in complex gas-phase molecules …
Waveforms For Optimal Sub-Kev High-Order Harmonics With Synthesized Two- Or Three-Colour Laser Fields, Cheng Jin, Guoli Wang, Hui Wei, Anh-Thu Le, C. D. Lin
Waveforms For Optimal Sub-Kev High-Order Harmonics With Synthesized Two- Or Three-Colour Laser Fields, Cheng Jin, Guoli Wang, Hui Wei, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
High-order harmonics extending to the X-ray region generated in a gas medium by intense lasers offer the potential for providing tabletop broadband light sources but so far are limited by their low conversion efficiency. Here we show that harmonics can be enhanced by one to two orders of magnitude without an increase in the total laser power if the laser's waveform is optimized by synthesizing two- or three-colour fields. The harmonics thus generated are also favourably phase-matched so that radiation is efficiently built up in the gas medium. Our results, combined with the emerging intense high-repetition MHz lasers, promise to …
Effects Of High-Flux Neutron Beams On He-3 Cells Polarized In Situ With Spin-Exchange Optical Pumping, E. Babcock, S. Boag, M. Becker, W. C. Chen, T. E. Chupp, T. R. Gentile, Gordon L. Jones, A. K. Petukhov, T. Soldner, T. G. Walker
Effects Of High-Flux Neutron Beams On He-3 Cells Polarized In Situ With Spin-Exchange Optical Pumping, E. Babcock, S. Boag, M. Becker, W. C. Chen, T. E. Chupp, T. R. Gentile, Gordon L. Jones, A. K. Petukhov, T. Soldner, T. G. Walker
Articles
Polarized He-3 produced by spin-exchange optical pumping (SEOP) has potential as a neutron spin filter for polarization and polarization analysis in many neutron-scattering and neutron particle physics applications. The advantage of the SEOP method is its suitability for providing continuous stable polarization over the course of long experiments. However, we have discovered that exposure to high neutron flux leads to additional strong relaxation mechanisms in the optically polarized alkali-metal vapor used to polarize the He-3. At a neutron flux density of 4.7 x 10(9) cm(-2) s(-1), the alkali-metal relaxation rate increased from 100 to 1000 s(-1) leading to reduced alkali-metal …
Inverted Velocity Profile In The Cylindrical Couette Flow Of A Rarefied Gas, Alejandro Garcia, K. Aoki, H. Yoshida, T. Nakanishi
Inverted Velocity Profile In The Cylindrical Couette Flow Of A Rarefied Gas, Alejandro Garcia, K. Aoki, H. Yoshida, T. Nakanishi
Faculty Publications
The cylindrical Couette flow of a rarefied gas is investigated, under the diffuse-specular reflection condition of Maxwell’s type on the cylinders, in the case where the inner cylinder is rotating whereas the outer cylinder is at rest. The inverted velocity profile for small accommodation coefficients, pointed out by Tibbs, Baras, and Garcia [Phys. Rev. E 56, 2282 (1997)] on the basis of a Monte Carlo simulation, is investigated extensively by means of a systematic asymptotic analysis for small Knudsen numbers as well as the direct numerical analysis of the Boltzmann equation, and the parameter range in which the phenomenon appears …
Inverted Velocity Profile In The Cylindrical Couette Flow Of A Rarefied Gas, Alejandro Garcia, K. Aoki, H. Yoshida, T. Nakanishi
Inverted Velocity Profile In The Cylindrical Couette Flow Of A Rarefied Gas, Alejandro Garcia, K. Aoki, H. Yoshida, T. Nakanishi
Alejandro Garcia
The cylindrical Couette flow of a rarefied gas is investigated, under the diffuse-specular reflection condition of Maxwell’s type on the cylinders, in the case where the inner cylinder is rotating whereas the outer cylinder is at rest. The inverted velocity profile for small accommodation coefficients, pointed out by Tibbs, Baras, and Garcia [Phys. Rev. E 56, 2282 (1997)] on the basis of a Monte Carlo simulation, is investigated extensively by means of a systematic asymptotic analysis for small Knudsen numbers as well as the direct numerical analysis of the Boltzmann equation, and the parameter range in which the phenomenon appears …
Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia
Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia
Alejandro Garcia
No abstract provided.
Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia
Comment On ‘‘Stress-Density Ratio Slip-Corrected Reynolds Equation For Ultra-Thin Film Gas Bearing Lubrication’’, Alejandro Garcia
Faculty Publications
No abstract provided.
Slip Length In A Dilute Gas, Alejandro Garcia, D. Morris, L. Hannon
Slip Length In A Dilute Gas, Alejandro Garcia, D. Morris, L. Hannon
Faculty Publications
We study the phenomenon of slip length using molecular dynamics and direct simulation Monte Carlo simulations of a dilute gas. Our work extends the range of Knudsen numbers that have been previously studied. In a recent paper, Bhattacharya and Lie [Phys. Rev. 43, 761 (1991)] suggest a logarithmic dependence of slip length on Knudsen number. By a simple redefinition of the mean free path, we obtain good agreement between simulation results and Maxwell theory for slip length. The anomalies seen by Bhattacharya and Lie appear to be due to their definition of the mean free path.
Slip Length In A Dilute Gas, Alejandro Garcia, D. Morris, L. Hannon
Slip Length In A Dilute Gas, Alejandro Garcia, D. Morris, L. Hannon
Alejandro Garcia
We study the phenomenon of slip length using molecular dynamics and direct simulation Monte Carlo simulations of a dilute gas. Our work extends the range of Knudsen numbers that have been previously studied. In a recent paper, Bhattacharya and Lie [Phys. Rev. 43, 761 (1991)] suggest a logarithmic dependence of slip length on Knudsen number. By a simple redefinition of the mean free path, we obtain good agreement between simulation results and Maxwell theory for slip length. The anomalies seen by Bhattacharya and Lie appear to be due to their definition of the mean free path.
Fluctuating Hydrodynamics In A Dilute Gas, Alejandro Garcia, G. Lie, E. Clementi
Fluctuating Hydrodynamics In A Dilute Gas, Alejandro Garcia, G. Lie, E. Clementi
Faculty Publications
Hydrodynamic fluctuations in a dilute gas subjected to a constant heat flux are studied by both a computer simulation and the Landau-Lifshitz formalism. The latter explicitly incorporates the boundary conditions of the finite system, thus permitting quantitative comparison with the former. Good agreement is demonstrated.
Fluctuating Hydrodynamics In A Dilute Gas, Alejandro Garcia, G. Lie, E. Clementi
Fluctuating Hydrodynamics In A Dilute Gas, Alejandro Garcia, G. Lie, E. Clementi
Alejandro Garcia
Hydrodynamic fluctuations in a dilute gas subjected to a constant heat flux are studied by both a computer simulation and the Landau-Lifshitz formalism. The latter explicitly incorporates the boundary conditions of the finite system, thus permitting quantitative comparison with the former. Good agreement is demonstrated.