scholarly journals New diagnostic methods for laser plasma- and microwave-enhanced combustion

2015 ◽  
Vol 373 (2048) ◽  
pp. 20140338 ◽  
Author(s):  
Richard B Miles ◽  
James B Michael ◽  
Christopher M Limbach ◽  
Sean D McGuire ◽  
Tat Loon Chng ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Molecular Species ◽  
Rayleigh Scattering ◽  
Thomson Scattering ◽  
Delayed Fluorescence ◽  
Diagnostic Methods ◽  
Temperature Fields ◽  
Rapid Diagnostics ◽  
Planar Imaging ◽  
Line Imaging

The study of pulsed laser- and microwave-induced plasma interactions with atmospheric and higher pressure combusting gases requires rapid diagnostic methods that are capable of determining the mechanisms by which these interactions are taking place. New rapid diagnostics are presented here extending the capabilities of Rayleigh and Thomson scattering and resonance-enhanced multi-photon ionization (REMPI) detection and introducing femtosecond laser-induced velocity and temperature profile imaging. Spectrally filtered Rayleigh scattering provides a method for the planar imaging of temperature fields for constant pressure interactions and line imaging of velocity, temperature and density profiles. Depolarization of Rayleigh scattering provides a measure of the dissociation fraction, and multi-wavelength line imaging enables the separation of Thomson scattering from Rayleigh scattering. Radar REMPI takes advantage of high-frequency microwave scattering from the region of laser-selected species ionization to extend REMPI to atmospheric pressures and implement it as a stand-off detection method for atomic and molecular species in combusting environments. Femtosecond laser electronic excitation tagging (FLEET) generates highly excited molecular species and dissociation through the focal zone of the laser. The prompt fluorescence from excited molecular species yields temperature profiles, and the delayed fluorescence from recombining atomic fragments yields velocity profiles.

2-D temperature fields in glow discharges measured with ultraviolet Filtered Rayleigh Scattering

2000 ◽  
Author(s):  
Azer Yalin ◽  
Yuriy Ionikh ◽  
Alexander Meshchanov ◽  
Richard Miles
Keyword(s):  
Rayleigh Scattering ◽  
Temperature Fields ◽  
Glow Discharges

Investigation of Filtered Rayleigh Scattering Techniques for Rig Testing Diagnostics

2014 ◽  
Author(s):  
Jordi Estevadeordal ◽  
Dmitry Opaits ◽  
Chiranjeev Kalra
Keyword(s):  
Rayleigh Scattering ◽  
High Pressures ◽  
Imaging Techniques ◽  
Mixing Layer ◽  
Temperature Measurements ◽  
Temperature Fields ◽  
Gas Temperature ◽  
Iccd Camera ◽  
Gas Molecules ◽  
Combustion Tests

A laboratory investigation of Filtered Rayleigh Scattering (FRS) techniques for high-resolution and high-accuracy temperature measurements in rig tests with high pressures and temperatures and combustion is presented. Imaging techniques based on filtered Rayleigh scattering have the potential for two-dimensional (2D) and near wall measurement of gas velocity and temperature fields among other properties. For gas temperature measurements, laser Rayleigh scattering from gas molecules are typically captured with an ICCD camera and temperature can be inferred from the number density measured from the image intensities. The accuracy challenges associated with property spatial variations, gas composition, and pressure and temperature conditions are investigated for the rig test environments. Representative examples including mixing layer, jet and vortex flows and flame and combustion tests are presented.

Unilateral Ectasia characterized by Advanced Diagnostic Tests

2016 ◽  
Vol 5 (1) ◽  
pp. 40-51 ◽  
Author(s):  
Bernardo Lopes ◽  
Marcella Q Salomão ◽  
Isaac C Ramos ◽  
Fernando Faria-Correia
Keyword(s):  
Visual Acuity ◽  
Femtosecond Laser ◽  
Diagnostic Tests ◽  
Diagnostic Methods ◽  
Distance Visual Acuity ◽  
Epithelial Thickness ◽  
Ring Segment ◽  
Intracorneal Ring Segment ◽  
The Right

ABSTRACT To describe a case of very asymmetric ectasia successfully treated by femtosecond laser-assisted intracorneal ring segment implantation, in which the diagnosis of unilateral ectasia in the right eye was based on the clinical findings including history, follow-up, and advanced diagnostic data. The patient's history was positive for ocular allergy with moderate- to-intense eye rubbing only in the right eye. The uncorrected distance visual acuity was 20/63 in the right eye and 20/32 in the left eye. The corrected distance visual acuity (CDVA) was 20/40 in the right eye (-1.75-4.00 × 35°) and 20/16 in the left eye (-0.50-0.25 × 115°). After femtosecond laser-assisted intracorneal ring segment implantation, the right eye improved CDVA to 20/20-1. Concerning ectasia/keratoconus diagnosis, the left eye remained stable over 1 year of follow-up with unremarkable topometric, tomographic, and biomechanical findings. Epithelial thickness mapping by spectral domain optical coherence tomography and very-high-frequency digital ultrasound demonstrated epithelial thickness within normal limits in the left eye. Advanced diagnostic methods along with clinical data enable the distinction from unilateral ectasia cases and subclinical (fruste) keratoconus. Literature review is also performed along with case presentation and discussion. How to cite this article Ramos IC, Reinstein DZ, Archer TJ, Gobbe M, Salomão MQ, Lopes B, Luz A, Faria-Correia F, Gatinel D, Belin MW, Ambrósio R Jr. Unilateral Ectasia characterized by Advanced Diagnostic Tests. Int J Kerat Ect Cor Dis 2016;5(1):40-51.

scholarly journals Diagnostic of the Symbiotic Stars Environment by Thomson, Raman and Rayleigh Scattering Processes

2015 ◽  
Vol 2 (1) ◽  
pp. 282-285
Author(s):  
M. Sekeráš ◽  
A. Skopal
Keyword(s):  
White Dwarf ◽  
Rayleigh Scattering ◽  
Neutral Hydrogen ◽  
Circumstellar Matter ◽  
Thomson Scattering ◽  
Symbiotic Stars ◽  
Hydrogen Atoms ◽  
Circumstellar Material ◽  
Long Period ◽  
Ionization Structure

Symbiotic stars are long-period interacting binaries consisting of a cool giant as the donor star and a white dwarf as the acretor. Due to acretion of the material from the giant’s stellar wind, the white dwarf becomes very hot and luminous. The circumstellar material partially ionized by the hot star, represents an ideal medium for processes of scattering. To investigate the symbiotic nebula we modeled the wide wings of the resonance lines OVI λ1032 Å, λ1038 Å and HeII λ1640 Å emission line in the spectrum of AG Dra, broadened by Thomson scattering. On the other hand, Raman and Rayleigh scattering arise in the neutral part of the circumstellar matter around the giant and provide a powerful tool to probe e.g. the ionization structure of the symbiotic systems and distribution of the neutral hydrogen atoms in the giant’s wind.

scholarly journals Pertussis: the disease and new diagnostic methods.

1988 ◽  
Vol 1 (4) ◽  
pp. 365-376 ◽  
Author(s):  
R L Friedman
Keyword(s):  
Young Children ◽  
Whooping Cough ◽  
Bacterial Virulence ◽  
Diagnostic Methods ◽  
Rapid Diagnostics ◽  
Major Health Problem ◽  
Major Health ◽  
Chronic Respiratory Infection ◽  
Effective Immunization ◽  
Infants And Young Children

Bordetella pertussis, the causative agent of whooping cough, produces an acute and chronic respiratory infection in infants and young children. B. pertussis is still a major health problem of young children throughout the world even though effective immunization against whooping cough is available. While predominantly a childhood disease, it has been reported also to be a cause of persistent cough in adults. This review discusses the numerous bacterial virulence factors that may play roles in the pathogenesis of pertussis and in immunity to infection. The present problems with pertussis diagnosis, recent advances, and future prospects for new and improved rapid diagnostics tests also are explored.

scholarly journals Absorption Spectra of the Prototype Hot-Jupiters: determination of atmospheric constituents and structure

2008 ◽  
Vol 4 (S253) ◽  
pp. 532-535 ◽  
Author(s):  
David K. Sing ◽  
A. Lecavelier ◽  
J.-M. Désert ◽  
A. Vidal-Madjar ◽  
G. Ballester
Keyword(s):  
High Temperature ◽  
Molecular Species ◽  
Transmission Spectrum ◽  
Optical Transmission ◽  
Rayleigh Scattering ◽  
Transmission Spectra ◽  
Hot Jupiters ◽  
Transmission Spectrum Analysis ◽  
Pressure Altitude

AbstractThe two prototype hot-Jupiter exoplanets HD209458b and HD189733b are currently offering an unprecedented view of their atmospheres. As discussed here, primary transit transmission spectra provide the opportunity to identify specific atomic and molecular species, determine their abundances, and recover temperature-pressure-altitude information. We present a reanalysis of existing HST/STIS data on HD209458b, providing a complete optical transmission spectrum. Analysis of this spectrum have revealed: (1) the planetary abundance of sodium which is ~2X solar (2) a depletion of sodium at high altitudes due to condensation or ionization (3) Rayleigh scattering by H2 (3) a high temperature at pressures of 10's mbar consistent with the dayside inversion (4) a separate high-altitude hot temperature from the planet's thermosphere and (5) likely absorption by TiO/VO. While HD209458b and HD189733b are currently the best candidates for these studies, another ~10 exoplanets are good targets with today's instruments for future transmission-based atmospheric detections.

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