Download or read book The Characterization and Monitoring of Trace Gases Using Laser Absorption Spectroscopy written by Byron David Green and published by . This book was released on 1976 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Trace Analysis of Specialty and Electronic Gases written by William M. Geiger and published by John Wiley & Sons. This book was released on 2013-07-15 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explores the latest advances and applications of specialty and electronic gas analysis The semiconductor industry depends upon a broad range of instrumental techniques in order to detect and analyze impurities that may be present in specialty and electronic gases, including permanent gases, water vapor, reaction by-products, and metal species. Trace Analysis of Specialty and Electronic Gases draws together all the latest advances in analytical chemistry, providing researchers with both the theory and the operating principles of the full spectrum of instrumental techniques available for specialty and electronic gas analysis. Moreover, the book details the advantages and disadvantages of each technique, steering readers away from common pitfalls. Featuring contributions from leading analytical and industrial chemists, Trace Analysis of Specialty and Electronic Gases covers a wide range of practical industrial applications. The book begins with the historical development of gas analysis and then focuses on particular subjects or techniques such as: Metals sampling and ICP-MS analysis Improvements in FTIR spectroscopy Water vapor analysis techniques New infrared laser absorption spectroscopy approaches GC/MS, GC/AED, and GC-ICP-MS techniques Gas chromatography columns Atmospheric pressure ionization mass spectrometry Lastly, the book examines gas mixtures and standards that are critical for instrument calibration. There are also two appendices offering information on fittings and material compatibility. With its thorough review of the literature and step-by-step guidance, Trace Analysis of Specialty and Electronic Gases enables researchers to take full advantage of the latest advances in gas analysis. Although the book's focus is the semiconductor and electronics industry, analytical chemists in other industries facing challenges with such issues as detection selectivity and sensitivity, matrix gas interference, and materials compatibility will also discover plenty of useful analytical approaches and techniques.
Download or read book Instrument Development for Atmospheric Research and Monitoring written by Jens Bösenberg and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jens Bosenberg Max-Planck-Institut fur Meteorologie, Bundesstr. 55, D-20146 Hamburg, Germany TESLAS, which stands for Tropospheric Environmental Studies by Laser Sounding, was formed in November 1987 as a subproject of EUROTRAC to enhance the measurement capabilities for vertical profiling of ozone in the troposphere by means of laser remote sensing. For studies of several atmospheric processes related to the formation and redistribution of photo-oxidants there was a clear need for measuring extended time series with appropriate vertical and temporal resolution. These could not be obtained by conventional in situ techniques, at least not with affordable effort, so remote sensing appeared to be the best way to obtain the required information. At the beginning of the subproject, some Differential Absorption Lidar (DIAL) systems for measuring the vertical distribution of ozone already existed, but their use was restricted to very few laboratories and very few measurement campaigns, since the instruments were highly complex, rather unreliable, and required extensive efforts for maintenance and operation by skilled scientists. In addition, the accuracy of these measurements under a variety of meteorological conditions was not really well established. The main tasks within TESLAS therefore were to develop fully the DIAL-methodology for remote sensing of tropospheric ozone, and to develop instruments which are accurate, reliable, easy to operate, and suitable for field deployment or airborne operation.
Download or read book Monitoring of Gaseous Pollutants by Tunable Diode Lasers written by R. Grisar and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: By now it has been nearly twenty years since the pioneering studies at the MIT-Lincoln Laboratories, Lexington, USA, demonstrated the unique capabilities of lead salt tunable diode lasers (TDL) for infrared absorption spectroscopy. The progress in the use of TDL instrumentation for a wide variety of scientific applications was described by a great number of papers since, however, comparatively few meetings were specifically devoted to this subject. In 1980 the conference on "High Resolution Infrared Spectroscopy Applications and Developments" at the National Bureau of Standards in Gaithersburg, USA, reviewed the state of the art of tunable diode lasers together with Fourier Transform Spectroscopy and other laser spectroscopic techniques. Three years later in 1983 the SPIE Conference in San Diego, USA, dedicated one meeting to "Tunable Diode Laser Development and Spectroscopy" Applications. It appeared appropriate after a further interval of three years to organize another meeting about this quickly advancing field. In November of 1986 an International Symposium on "Monitoring of Gaseous Pollutants by Tunable Diode Lasers" was organized by and held at the Fraunhofer-Insti tut fuer Physikalische Messtechnik in Freiburg, FRG. The main emphasis of this conference was put on the applications of TDL techniques to the solution of problems of environmental relevance : The measurement of atmospheric trace gases and the monitoring of exhaust gases from automobile and power plant stack emitters. The state of diode laser development and application of TDL instruments to scientific molecular spectroscopy were not directly subjects of the meeting.
Download or read book Applications of Infrared Laser Spectroscopy to Breath Analysis written by Beth L. Cummings and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this thesis is concerned with development of spectroscopic detection methods based on absorption spectroscopy using semiconductor lasers, with particular ref- erence to the field of medical diagnostics through breath analysis. The first part of this thesis deals with the design and testing of a prototype analyser for simultaneous monitoring of the exchange gases 02, C02 and H20 in breath. The aim of this analyser is to provide information required to monitor respiration, with potential use in intensive care monitoring or during anaesthesia. The relatively high concentrations of these gases in breath and read- ily available diode laser sources make detection in the near-infrared (NIR) ideal. However, the relatively weakly absorbing A-band 02 transitions at 760 nm require the application of a sensitive spectroscopic method, cavity enhanced absorption spectroscopy (CEAS). In contrast, CO2 and H20 are monitored using direct single pass absorption spectroscopy, with transitions arising from the 21/1 + 1/3 band at 2 uu: and 1/1 + 1/3 band at 1.3 p,m, re- spectively. It has been demonstrated that these gases can be detected simultaneously over a short pathlength (2.74 - 4 cm) in the respiratory flow by combining various spectroscopic methodologies and real-time data analysis. This analyser is shown to offer a viable alter- native for monitoring respiration, exhibiting absolute detection limits of changes of 0.26 % O2, 0.02 % CO2 and 0.003 % H20 with a 10 ms time resolution, which are comparable to current mass spectrometry based methods, but without their inherent delays. Following this, investigations into the detection of the main gas constituents in breath in the NIR employing noise-reduction modulation based spectroscopic techniques, namely wavelength and frequency modulation (WMS and FMS respectively) are also reported. The described WMS studies on water at 1.37 ust: provide a demonstration of conventional WMS detection, as well as a "proof-of-principle" example of a relatively new approach to calibrat- ing the non-absolute information obtained from a WMS absorption signal. Typically WMS spectra are calibrated using mixtures of known gas concentrations or an absolute direct absorption spectrum where possible. In this work however, a self-calibrating method, the phasor decomposition method (PDM), is employed and the returned concentration from this ~alibration is compared to direct absorption measurement. From this, the calculated concentration using the PDM is found to differ by 9 % from the concentration value ob- tained by direct absorption, providing an alternative method of calibration for when direct absorption measurements are not possible. The use of FMS in the NIR is also demon- strated as a potential alternative to CEAS for monitoring O2 at 760 nm. FMS detection is performed on atmospherically broadened 02 and a time-normalised O!min(t) of 2.45x10-6 cm-1 s~ is obtained, which is two orders of magnitude less sensitive than the value of 1 O!min(t) = 2.35x10-8 cm "! S2 obtained with CEAS. This combined with the experimental I requirements of an FMS system, make its use for detection of 02 a less practicable option compared to CEAS for real-time breath analysis. The latter work in this thesis involves a change in focus to detection of trace gases in breath in the mid-infrared (MlR). The move of spectroscopic detection to the MlR exploits the larger absorption cross-sections available in this region, and to achieve this, a relatively new form of semiconductor laser, the quantum cascade laser (QCL) is used. The design of a continuous wave QCL spectrometer at 8 usx: and its operating characteristics are demon- strated and improvements in its performances are also discussed. This QCL system is then utilised to demonstrate the potential of monitoring species in breath, namely the narrow- band absorber methane and the broadband absorber acetone, taking into consideration the potential interference from other absorbing species in breath and the different spectroscopic characteristics exhibited by these molecules. Finally, the potential to further improve the sensitive detection of trace gases in breath in the MlR is also investigated with studies on the use of CEAS and multipass cells. In this work, the molecule of interest is the biomarker OGS, using transitions of the 2V2 band at 1031 cm-I, that are probed using a 10 usx: QCL. The application of CEAS in the MlR is not as well developed as in the NIR, and the experimental consequences of using optical cavities at these wavelengths, where equipment tends to be more limited, are investigated and sensitivities discussed in the context of other literature. The experimental procedure of optimising a cavity for CEAS using the off-axis alignment method is also studied in detail, as well as the addition ofWMS to further improve the signal quality. An effective absorption pathlength of ,....., 100 m was achieved in the cavity, with a bandwidth reduced O!min(BW) 1 of 1.7x10-7 cm"? HZ-2 using WMS CEAS achieved. With the poorer quality optics and limitations in equipment in the MlR for CEAS experiments, the use of a multipass cell, a 238 m Herriott cell, is also investigated as an alternative to the use of an optical cavity at 10 tui". Detection of OCS using direct absorption and WMS is demonstrated in the 1 Herriott cell, achieving O!min(BW) = 2.03xlO-8 cm "! HZ-2 using WMS. This shows an improvement in sensitivity compared to WMS CEAS, and also shows the potential for future work on biomarker detection, as it approaches the r-- ppb levels required for breath analysis.
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 Development and Application of Diode Laser Based Optical Sensors for Continuous Monitoring of Trace Atmospheric Constituents written by Md. Shafiqul Islam Aziz and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An improved version of an automated near infra-red continuous wave cavity ring down spectrometer with sample preconcentration has been developed, for the detection of trace gases in the atmosphere and isotopologue ratio analysis. Three different lasers operating at wavelengths in the range 1.5-1.6 urn have been used for the experiments in conjunction with three different pre-concentration systems. The instrument has been used for three separate studies: continuous measurement of ethene (C2H4) in Bristol air; detection of nitrous oxide (N20) in ambient air; and acetylene isotopologue ratio (13CH4/12CH4) analysis in cigarette smoke samples. Mixing ratios of ethene have been observed to vary from 0.6 ppbv to 1.2 ppbv in Bristol air with a strong influence of the prevailing wind direction. Winds from the west and the north were observed to decrease and increase the ethene mixing ratio in Bristol air respectively. The observed variations have been discussed with consideration of probable sources and sinks and different meteorological parameters. Nitrous oxide in Bristol air has been observed to have a mixing ratio of ~320 ppb; consistent with global abundance of this long-lived greenhouse gas. Acetylene isotopologue ratios have been measured in smoke samples from two different brands of cigarette chosen as a test source of C2H2 from combustion of plant material. The average s\3e value of the five consecutive determinations for each cigarette brand was found to be -11.86 ± 0.55 %0 (Marlboro) and -4.98± 0.39 %0 (Lambert & Butler). The observed isotopologue ratios match closely with similar measurement of different samples derived from biomass burning conducted in different laboratories and analysed using isotopologue ratio mass spectrometry (IRMS). An improved version of a mid infra-red cavity enhanced absorption spectroscopy (CEAS) apparatus has been developed for isotopologue ratio analysis in gas samples. A difference frequency generation (DFG) based laser system was used as source of mid-IR radiation and a lock-in amplifier was used to demodulate the signal from sources of noise. The spectrometer has been used successfully to conduct methane isotopologue ratio analysis (13CH4/12CH4) in a 5% methane mixture in argon and carbon dioxide (COL) buffer gas. An average isotopologue ratio value of -47.3 ± 2.3 %0 has been observed which matches closely with two separate measurements on this standard sample, one using IRMS and another using a commercial near IR cavity ring down spectrometer.
Download or read book Advances in Spectroscopic Monitoring of the Atmosphere written by Weidong Chen and published by Elsevier. This book was released on 2021-06-09 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Spectroscopic Monitoring of the Atmosphere provides a comprehensive overview of cutting-edge technologies and monitoring applications. Concepts are illustrated by numerous examples with information on spectroscopic techniques and applications widely distributed throughout the text. This information is important for researchers to gain an overview of recent developments in the field and make informed selections among the most suitable techniques. This volume also provides information that will allow researchers to explore implementing and developing new diagnostic tools or new approaches for trace gas and aerosol sensing themselves. Advances in Spectroscopic Monitoring of the Atmosphere covers advanced and newly emerging spectroscopic techniques for optical metrology of gases and particles in the atmosphere. This book will be a valuable reference for atmospheric scientists, including those whose focus is applying the methods to atmospheric studies, and those who develop instrumentation. It will also serve as a useful introduction to researchers entering the field and provide relevant examples to researchers and students developing and applying optical sensors for a variety of other scientific, technical, and industrial uses. - Overview of new applications including remote sensing by UAV, laser heterodyne radiometry, dual comb spectroscopy, and more - Features in-situ observations and measurements for real-world data - Includes content on leading edge optical sensors
Download or read book Monitoring of Gaseous Pollutants by Tunable Diode Lasers written by R. Grisar and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the International Symposium held in Freiburg, F.R.G., October 17-18, 1988 organized by the Fraunhofer Institut für Physikalische Messtechnik (Freiburg) under the Auspices of the Commission of the European Communities
Download or read book Monitoring of Gaseous Pollutants by Tunable Diode Lasers written by R. Grisar and published by . This book was released on 1992 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Divided into four sections, this work presents the proceedings of an international symposium on monitoring of gaseous pollutants by tunable diode lasers.
Download or read book Trace Gas Monitoring by Open path Tunable Diode Laser Absorption Spectrometer OP TDLAS written by University of Victoria (B.C.). Centre for Earth and Ocean Research and published by . This book was released on 1996* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental Trace Gas Detection Using Laser Spectroscopy written by and published by . This book was released on 1998 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Co laser Photoacoustic Spectroscopy of Gases and Vapors for Trace Gas Analysis written by Stefan Bernegger and published by . This book was released on 1988 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of Atmospheric Trace Gases Using Open Path Differential UV Absorption Spectroscopy for Urban Pollution Monitoring written by Philip Nathaniel Martin and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Special issue environmental trace gas detection using laser spectroscopy written by and published by . This book was released on 1998 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development Characterization and Miniaturization of a Trace Gas Detection System for NO2 in Air Based on Photoacoustic Spectroscopy written by Thomas Rück and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
