Download or read book Utilization of Multiple Harmonics of Wavelength Modulation Absorption Spectroscopy for Practical Gas Sensing written by Kai Sun and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To meet more rigorous criteria for environmental-unfriendly emissions and to increase energy efficiency, in-situ real-time sensors are needed to optimize the performance of next-generation energy systems. The emergence of high-quality (narrow linewidth, fast tuning capability) tunable diode lasers (TDLs) has enabled the use of wavelength modulation spectroscopy (WMS) for harsh industrial applications. Compared to conventional direct absorption measurements, WMS has the advantage of 10-100 times better detection sensitivity, avoids the need to obtain a zero-absorption baseline, and provides much better isolation from the beam steering, non-absorption transmission loss (e.g., light scattering) or mechanical vibrations. Many models have been developed to interpret the measured WMS signal into absolute absorption. However, most of these models are limited to specific applications by a wide variety of assumptions and approximation most of which deal with the simultaneous intensity and wavelength modulation of injection-current-modulated diode lasers. In this dissertation, two generalized approaches to analyze the WMS absorption signal were developed that account for non-ideal simultaneous intensity modulation of laser output when injection current variation is used for wavelength modulation. The first approach is ideal for wavelength-fixed WMS (the laser mean wavelength is fixed) analysis and the second approach is ideal for wavelength-scanned (the laser mean wavelength is scanned) WMS analysis, and both of them can be used for arbitrary modulation depth, or laser architectures even when severe non-linear intensity modulation occurs simultaneously with wavelength modulation. These new interpretations of WMS absorption signals provide the potential for extended and improved use of WMS for practical gas sensing in a much wider array of applications. The first approach built on earlier work in our laboratory. The analysis of calibration-free, 1f-normalized, WMS-2f absorption signals was extended to higher harmonics (for example 3f, 4f ...) using traditional Fourier analysis. The new approach and procedure developed also accounts for non-ideal wavelength-tuning of the injection-current tuned laser as well as etalon interference from the optical components in the laser line-of-sight (LOS). This approach was validated using measurements of the CO transition of R (11) in the 1st overtone band near 2.3æm in a laboratory cell at room temperature for a range of CO mole fractions (0.21-2.8%) and pressures (5-20atm). For high-pressure gas sensing, wavelength modulation spectroscopy with higher-order harmonic detection (WMS-nf, n> 2) was found to have less influence from the WMS background signals when the selected modulation depth was near the optimal modulation depth for the WMS-2f signal. This WMS approach was then used for measurements in a pilot-scale entrained-flow coal gasifier at the University of Utah. Even though the particulate scattering reduced the laser transmission as much as 99.997%, and pressure broadening at the 18atm (~250psig) operating pressure blended the absorption transitions, successful in-situ rapid-time-resolved 1f-normalized WMS-2f absorption measurements for gas temperature and H2O mole fraction were made. Based on lessons learned during the gasifier measurements at Utah and a desire to eventually develop real-time sensors for long-term monitoring, a second approach for WMS analysis was developed that differs from previous WMS analysis strategies in two significant ways: (1) the measured laser intensity without absorption is used to simulate the transmitted laser intensity with absorption and (2) digital lock-in and low-pass filter software is used to expand both simulated and measured transmitted laser intensities into harmonics of the modulation frequency, WMS-nf (n=1,2,3 ...), avoiding the need for an analytic model of intensity modulation or Fourier expansion of the simulated WMS harmonics. The new method was demonstrated and validated with WMS of H2O dilute in air (1atm, 296K, near 1392nm). WMS-nf harmonics for n=1 to 6 are extracted and the simulations and measurements are found in good agreement for the entire WMS lineshape. This new analysis scheme was applied to monitor the synthesis gas output from an engineering-scale transport reactor coal gasifier at the National Carbon Capture Center. There the pressures ranged up to 15 atm (~220psig) and temperatures up to 650K. Continuous monitoring of moisture level in the gasifier output with 2s time resolution was performed by the TDL sensor for more than 500 hours, including the periods of burner ignition, combustion heating with a propane flame, coal combustion, coal gasification, and reactor shut-down via coal-feed termination. In addition, a novel and rapid approach to determine the collisional linewidth via the WMS signals at different harmonics at the modulation frequency is presented. The peak values of the WMS-nf absorption spectrum near the transition line center are used to infer the absorption lineshape, which is exploited here to extract collision-broadening halfwidth from the ratio of WMS-4f/WMS-2f (or other even harmonics) signals when the mean laser wavelength is tuned to line center. Measurement of the absorption linewidth enables quantitative WMS measurements without the need for a collision-broadening database. Alternatively, when collision-broadened spectral data are available, a WMS-based pressure sensor can be realized, and a demonstration using the 4fpeak/2fpeak ratio gives less than 0.7% difference for the pressure for cell measurements from 100 torr to 753 torr. These new WMS analysis schemes have been validated in near commercial environments and illustrate the potential of their use to develop practical TDL sensors for a wide variety of industrial applications.
Download or read book Wavelength modulation Spectroscopy for Determination of Gas Properties in Hostile Environments written by Christopher S. Goldenstein and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 40 years, tunable diode laser absorption spectroscopy (TDLAS) sensors have matured into a practical technology for providing non-intrusive, in-situ measurements of gas properties in a number of hostile energy systems. However, the applicability of TDLAS sensors has been limited by a number of fundamental measurement challenges including: beam-steering, non-absorbing transmission losses, interfering emission, line-of-sight non-uniformities, and broad and blended absorption spectra at high pressures. This work presents the development and demonstration of several novel calibration-free wavelength-modulation spectroscopy (WMS) techniques and sensors that enable high-fidelity measurements of gas properties in highly non-uniform gases and high-pressure gases. These WMS techniques are demonstrated with measurements of gas temperature, H2O, pressure, and velocity in two model scramjet combustors and a pulse detonation combustor.
Download or read book A Practical Guide to Graphite Furnace Atomic Absorption Spectrometry written by David J. Butcher and published by John Wiley & Sons. This book was released on 1998-03-23 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Die Atomabsorptionsspektroskopie mit Graphitrohrküvetten wird vor allem in der Material- und Umweltwissenschaft zur Untersuchung von Legierungen, Keramiken, Polymeren, Kompositwerkstoffen und Abwässern eingesetzt. Dieses umfangreiche Handbuch enthält viele praktische Beispiele, Tips und Tricks sowie Angaben zur instrumentellen Ausrüstung, zu modernen Entwicklungen und zur Fehlersuche: Eine wahre Fundgrube für den Praktiker, jedoch auch für Einsteiger geeignet - mit verschiedenen Anhängen, historischen Hintergrundinformationen, Literaturverzeichnissen und einem Glossar der verwendeten Fachterminologie. (06/98)
Download or read book State of the art Laser Gas Sensing Technologies written by Yufei Ma and published by MDPI. This book was released on 2020-03-05 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trace gas sensing technologies are widely used in many applications, such as environmental monitoring, life science, medical diagnostics, and planetary exploration. On the one hand, laser sources have developed greatly due to the rapid development of laser media and laser techniques in recent years. Some novel lasers such as solid-state, diode, and quantum cascade lasers have experienced significant progress. At present, laser wavelengths can cover the range from ultraviolet to terahertz, which could promote the development of laser gas sensing technologies significantly. On the other hand, some new gas sensing methods have appeared, such as photothermal spectroscopy and photoacoustic spectroscopy. Laser spectroscopy-based gas sensing techniques have the advantages of high sensitivity, non-invasiveness, and allowing in situ, real-time observation. Due to the rapid and recent developments in laser source as well as the great merits of laser spectroscopy-based gas sensing techniques, this book aims to provide an updated overview of the state-of-the-art laser gas sensing technologies.
Download or read book Sensitive Detection of Novel Effects and Characteristic Signal Structure of Higher Harmonic Detection in Wavelength Modulation Spectroscopy written by Mohammad Amir Khan and published by . This book was released on 2009 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bulletin of the Atomic Scientists written by and published by . This book was released on 1961-05 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Download or read book State of the Art Laser Spectroscopy and its Applications Volume II written by Yufei Ma and published by Frontiers Media SA. This book was released on 2023-02-09 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Green Electronics written by Cristian Ravariu and published by BoD – Books on Demand. This book was released on 2018-06-20 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Green Electronics book is intended to stimulate people's thinking toward the new concepts of an environment-friendly electronics - the main challenge in the future. The book offers multiple solutions to push the classical electronic industry toward green concepts, aided by nanotechnologies, with revolutionary features that provide low power consumption in electronics, use biomaterials for integrated structures, and include environmental monitoring tools. Based on organic semiconductors/insulators without toxic precursors, green electronic technologies launched promising devices like OLED, OTFT, or nano-core-shell transistors. The Green Electronics book successfully presents the recent directions collected worldwide and leaves free space for continuing year by year with new subtopics.
Download or read book Air Monitoring by Spectroscopic Techniques written by Markus W. Sigrist and published by John Wiley & Sons. This book was released on 1994-03-31 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading experts discuss the characteristics, advantages, limitations and future aspects of modern spectroscopic techniques for environmental analysis. Demonstrates how these methods can be applied to trace gas detection and assessment. Concentrates on the latest techniques--both laser and non-laser based--which offer advantages for air pollution and gas monitoring as opposed to more conventional methods. Numerous examples of applications illustrate the potential of the techniques backed up by cutting-edge information and representative data.
Download or read book 39th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit July 20 23 2003 Huntsville Alabama 03 4550 03 4599 written by and published by . This book was released on 2003 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Resolution of Overlapping Spectra by Wavelength Modulation Spectroscopy written by Audra Michiele Bullock and published by . This book was released on 2000 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Industrial Applications of Laser Remote Sensing written by Tetsuo Fukuchi and published by Bentham Science Publishers. This book was released on 2012 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: This e-book is an essential review of land-based laser sensing methods, such as differential absorption, Raman scattering, laser-induced fluorescence, Doppler effect methods, laser-induced breakdown spectroscopy, and laser ultrasonics, and their respective application to specific industrial needs, such as natural gas leak detection, hydrogen gas leak detection, pollutant detection, wind profiling for windmill sites, minor constituent monitoring and concrete structure health monitoring. Readers will gain an updated overview of laser remote sensing techniques and their applications to the industrial environment.
Download or read book Spectroscopy and Optical Diagnostics for Gases written by Ronald K. Hanson and published by Springer. This book was released on 2015-10-26 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text provides an introduction to the science that governs the interaction of light and matter (in the gas phase). It provides readers with the basic knowledge to exploit the light-matter interaction to develop quantitative tools for gas analysis (i.e. optical diagnostics) and understand and interpret the results of spectroscopic measurements. The authors pair the basics of gas‐phase spectroscopy with coverage of key optical diagnostic techniques utilized by practicing engineers and scientists to measure fundamental flow‐field properties. The text is organized to cover three sub‐topics of gas‐phase spectroscopy: (1) spectral line positions, (2) spectral line strengths, and (3) spectral lineshapes by way of absorption, emission, and scattering interactions. The latter part of the book describes optical measurement techniques and equipment. Key subspecialties include laser induced fluorescence, tunable laser absorption spectroscopy, and wavelength modulation spectroscopy. It is ideal for students and practitioners across a range of applied sciences including mechanical, aerospace, chemical, and materials engineering.
Download or read book Springer Handbook of Experimental Fluid Mechanics written by Cameron Tropea and published by Springer Science & Business Media. This book was released on 2007-10-09 with total page 1570 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accompanying DVD-ROM contains ... "all chapters of the Springer Handbook."--Page 3 of cover.
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2007 with total page 990 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic and Molecular Spectroscopy written by Sune Svanberg and published by Springer Nature. This book was released on 2023-01-06 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wide-ranging review of modern spectroscopic techniques such as X-ray, photoelectron, optical and laser spectroscopy, and radiofrequency and microwave techniques. On the fundamental side the book focuses on physical principles and the impact of spectroscopy on our understanding of the building blocks of matter, while in the area of applications particular attention is given to those in chemical analysis, photochemistry, surface characterisation, environmental and medical diagnostics, remote sensing and astrophyscis. The Fourth Edition also provides the reader with an update on laser cooling and trapping, Bose-Einstein condensation, ultra-fast spectroscopy, high-power laser/matter interaction, satellite-based astronomy and spectroscopic aspects of laser medicine.
Download or read book AIAA Fourth International Aerospace Planes Conference 92 5073 92 5107 written by and published by . This book was released on 1992 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
