Download or read book Lasers in Chemical Analysis written by Gary M. Hieftje and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lasers are relatively recent additions to the analytical scientist's arsenal. Because of this, many analysts-whether their concern is research or some range of applications-are in need of a tutorial introduction not only to the principles of lasers, their optics, and radiation, but also to their already diverse and burgeoning applications. The artic1es presented in this volume, carefully enhanced and edited from lectures prepared for the ACS Division of Analytical Chemistry 1979 Summer Symposium, are designed to provide just such a broad introduction to the subject. Thus, in addition to several excellent chapters on laser fundamentals, there are many practically oriented artic1es dealing with laser analytical methodology, inc1uding techniques based on the absorption oflaser radiation, on laser-induced fluorescence, and on some of the uses of lasers in chemical instru mentation. The first of these sections is pivotal and reflects in part our philosophy in organizing this collection. The authors of the initial chapters were invited not only because of their expertise in the field of lasers and analytical chemistry, but also because their didactic approach to writing and their c1arity of presentation were well known to us. It is our hope that individual readers with little knowledge of lasers will gain from these introductory chapters sufficient information to render the later, more detailed artic1es both useful and meaningful.

Download or read book Time resolved Planar Laser Induced Fluorescence of Laser Ignition of a Methane air Mixture written by H. El-Rabii 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 Laser induced Fluorescence for Medical Diagnostics written by Stefan Andersson-Engels and published by . This book was released on 1989 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preliminary Laser Induced Fluorescence Measurements in Several Facilities in Preparation for Application to Studies in the High Enthalpy Shock Tunnel Gottingen HEG written by W. H. Beck and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tracer based Planar Laser induced Fluorescence Diagnostics written by Brian Ho-yin Cheung and published by Stanford University. This book was released on 2011 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two advances to tracer-based planar laser-induced fluorescence (PLIF) diagnostics are presented in this work. The first improvement is the development of a 3-pentanone fluorescence quantum yield (FQY) database and model for a wide range of conditions in support of quantitative PLIF diagnostics. In addition, this work presents a sensitive, time-resolved tracer-based PLIF diagnostic, accomplished by using a continuous-wave (CW) laser with the high-FQY tracer toluene. Because of its ease of use and desirable photophysical properties, PLIF diagnostics using 3-pentanone as a tracer are common, particularly for internal combustion engine (ICE) diagnostics. Thus, there is a need for 3-pentanone FQY measurements and modeling over a wide range of temperatures, pressures, and excitation wavelengths. For insight into the collisionless process in the FQY model, measurements were made in 3-pentanone vapor at low-pressures across a range of temperatures using a flowing cell. Laser excitation with 248, 266, 277, 308 nm wavelengths were utilized, and Rayleigh scattering of the laser beam was used to calibrate the optical efficiency of the collection optics and detector. This low-pressure data allows calculation of the 3-pentanone fluorescence rate and non-radiative de-excitation rate in the fluorescence model. The vibrational relaxation cascade parameter for 3-pentanone collisions was also determined. Measurements of 3-pentanone FQY were also made over a range of temperatures and pressures relevant to diagnostic applications, and, in particular, combined high-temperature and high-pressure conditions applicable to internal combustion engines (ICE). These data were collected in a custom-built optical cell capable of simultaneous high-pressure and high-temperature conditions. The behavior of the FQY in nitrogen for temperatures up to 745 K and in air up to 570 K was examined for pressures from 1 to 25 bar. These data were used to further optimize the parameters in the FQY model representing collisional processes. The large quantity of data with 308 nm excitation allowed optimization of the nitrogen quenching rate, and data in air were used to optimize the oxygen quenching rate. These data were also used to optimize the vibrational relaxation parameters for nitrogen and oxygen. The model with the updated parameters is consistent with the data collected in the current work, as well as with fluorescence measurements made in optical ICEs up to 1100 K and 28 bar. Another area of tracer-based PLIF diagnostics development is time-resolved imaging. Because PLIF diagnostics are often performed using pulsed lasers, the time resolution of measurements is limited to the pulse rate of laser. Use of a high-powered visible laser with an off-the-shelf cavity frequency doubler is shown to produce a moderate-power CW beam in the ultraviolet wavelength regime. Application of this CW source to excite toluene, a high-FQY tracer, yields a sensitive, time-resolved tracer-based PLIF diagnostic. Fluctuation detection limits for tracer mole fraction were investigated by applying the diagnostic to an atmospheric temperature and pressure nitrogen jet seeded with 4% toluene, and detection limits of better than 1% of the maximum toluene mole fraction were achieved for detection of fluorescence signal at a point, along a line, and over a plane. The diagnostic was also demonstrated on a turbulent jet for line and planar detection and demonstrated the potential for toluene time-resolved PLIF diagnostics with CW lasers.

Download or read book Optics and Lasers in Biomedicine and Culture written by C. Fotakis and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following the previous OWLS conferences devoted to optics in life sciences, the 5th Conference focused on recent achievements in applying lasers and optics in biomedicine and in the preservation of our cultural heritage. Particular attention is thus paid to laser diagnostics in medicine, interaction of laser radiation with biological tissue, and the development of new systems for these studies. The contributors to this volume cover such international research activities as photon migration in tissue, fibre optics, lasers in dermatology, ENT, cardiology, and in art conservation, imaging techniques in archaeology, laser technologies in contemporary art, and new laser and opto-electronic systems for biomedical and art-related studies.

Download or read book Strategies for Planar Laser induced Fluorescence Thermometry in Shock Tube Flows written by Ji Hyung Yoo and published by Stanford University. This book was released on 2011 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis was motivated by the need to better understand the temperature distribution in shock tube flows, especially in the near-wall flow regions. Two main ideas in planar laser-induced fluorescence (PLIF) diagnostics are explored in this thesis. The first topic is the development of a single-shot PLIF diagnostic technique for quantitative temperature distribution measurement in shock tube flow fields. PLIF is a non-intrusive, laser-based diagnostic technique capable of instantaneously imaging key flow features, such as temperature, pressure, density, and species concentration, by measuring fluorescence signal intensity from laser-excited tracer species. This study performed a comprehensive comparison of florescence tracers and excitation wavelengths to determine the optimal combination for PLIF imaging in shock tube flow applications. Excitation of toluene at 248nm wavelength was determined to be the optimal strategy due to the resulting high temperature sensitivity and fluorescence signal level, compared to other ketone and aromatic tracers at other excitation wavelengths. Sub-atmospheric toluene fluorescence yield data was measured to augment the existing photophysical data necessary for this diagnostic technique. In addition, a new imaging test section was built to allow PLIF imaging in all regions of the shock tube test section, including immediately adjacent to the side and end walls. The signal-to-noise (SNR) and spatial resolution of the PLIF images were optimized using statistical analysis. Temperature field measurements were made with the PLIF diagnostic technique across normal incident and reflected shocks in the shock tube core flow. The resulting images show uniform spatial distribution, and good agreement with conditions calculated from the normal shock jump equations. Temperature measurement uncertainty is about 3.6% at 800K. The diagnostic was also applied to image flow over a wedge. The resulting images capture all the flow features predicted by numerical simulations. The second topic is the development of a quantitative near-wall diagnostic using tracer-based PLIF imaging. Side wall thermal boundary layers and end wall thermal layers are imaged to study the temperature distribution present under constant pressure conditions. The diagnostic technique validated in the shock tube core flow region was further optimized to improve near-wall image quality. The optimization process considered various wall materials, laser sheet orientations, camera collection angles, and optical components to find the configuration that provides the best images. The resulting images have increased resolution (15[Mu]m) and are able to resolve very thin non-uniform near-wall temperature layers (down to 60[Mu]m from the surface). The temperature field and thickness measurements of near-wall shock tube flows under various shock conditions and test gases showed good agreement with boundary layer theory. To conclude this thesis, new applications and future improvements to the developed PLIF diagnostic technique are discussed. These suggested refinements can provide an even more robust and versatile PLIF imaging technique capable of measuring a wider range of flow conditions near walls.

Download or read book Laser Induced Fluorescence Measurements and Modeling of Nitric Oxide in High pressure Premixed Flames written by and published by . This book was released on 1994 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser Induced Fluorescence Measurements and Modeling of Nitric Oxide in Counterflow Diffusion Flames written by and published by . This book was released on 2000 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lasers in Chemical Analysis written by Gary M. Hieftje and published by Humana Press. This book was released on 1981-05-31 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lasers are relatively recent additions to the analytical scientist's arsenal. Because of this, many analysts-whether their concern is research or some range of applications-are in need of a tutorial introduction not only to the principles of lasers, their optics, and radiation, but also to their already diverse and burgeoning applications. The artic1es presented in this volume, carefully enhanced and edited from lectures prepared for the ACS Division of Analytical Chemistry 1979 Summer Symposium, are designed to provide just such a broad introduction to the subject. Thus, in addition to several excellent chapters on laser fundamentals, there are many practically oriented artic1es dealing with laser analytical methodology, inc1uding techniques based on the absorption oflaser radiation, on laser-induced fluorescence, and on some of the uses of lasers in chemical instru mentation. The first of these sections is pivotal and reflects in part our philosophy in organizing this collection. The authors of the initial chapters were invited not only because of their expertise in the field of lasers and analytical chemistry, but also because their didactic approach to writing and their c1arity of presentation were well known to us. It is our hope that individual readers with little knowledge of lasers will gain from these introductory chapters sufficient information to render the later, more detailed artic1es both useful and meaningful.

Download or read book Laser Technology and its Applications written by Yufei Ma and published by BoD – Books on Demand. This book was released on 2019-01-03 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The laser has become more and more important in scientific research and industrial applications. Now, the laser wavelength can cover the range from ultraviolet to terahertz and output laser performance has significantly progressed in recent years. This book is focused on the advanced diode laser, fiber laser, and their applications in laser ablation, laser-introduced fluorescence, and laser treatment. The advantages of laser technology are shown comprehensively.

Download or read book Investigation of Low pressure Laser Induced Fluorescence for Measuring Temperature Profiles in a Rarefied Gas written by Thomas Orville Leimkuehler and published by . This book was released on 2000 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a rarefied gas, heat transfer in the transition regime (i.e., Knudsen number range of 0.1 to 10) is affected by molecular as well as gas-surface interactions. Theoretical results for the heat transfer can be obtained through computational solutions of the Boltzmann equation and appropriate intermolecular and gas-surface interaction models. As with all computational and phenomenological models, experimental verification is required. In this work, a low-pressure laser induced fluorescence (LIF) technique is investigated for measuring temperature profiles between parallel flat plates, and the results are compared to theoretical predictions. Iodine vapor is used as the gas medium due to its attractive spectral properties. Two surfaces of a closed, short cylindrical iodine cell are employed as a parallel flat plate geometry and are maintained at different temperatures. Cold and hot plate temperature combinations of (1) 20°C and 70°C, respectively, and (2) 20°C and 115°C, respectively, were used. Calibration measurements were performed at uniform temperatures of 45°C and 70°C, Solid iodine stem temperatures of 0°C and -20°C, corresponding to pressures of 30 mtorr and 3 mtorr, respectively, and Knudsen numbers of 0.05 and 0.5, respectively, were investigated. The data shows the expected trends, indicating observable temperature jumps at the surfaces and matching well with the theoretical predictions in the bulk gas. Deviations from the theory were largest near the surface, possibly a result of the limitations of the theoretical models for this particular experimental case. In addition, problems stemming from fluctuations of the chamber pressure as well as attenuation of the excitation laser beam affected collection of definitive temperature profile measurements. However, much progress with the low-pressure LIF technique has been made, and the technique continues to look promising for obtaining accurate and reliable temperature profile measurements in the transition regime.

Download or read book Optical and Laser Diagnostics written by C Arcoumanis and published by CRC Press. This book was released on 2016-04-19 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the automotive industry to blood flow monitoring, optical techniques and laser diagnostics are becoming integral parts in engineering and medical instrumentation. Written by leading global experts from industry, academic groups, and laboratories, this volume provides an international perspective on both existing applications and leading-edge r

Download or read book Status of Laser induced Fluorescence and Planar Laser induced Fluorescence Measurements in the AEDC HEAT H2 Arc Heater Facility written by W. M. Ruyten and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Premixed Flames written by Nedunchezhian Swaminathan and published by Cambridge University Press. This book was released on 2011-04-25 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: A work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.

Download or read book Laser Induced Fluorescence written by Puspendu Kumar Das and published by . This book was released on 1984 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Operando Research in Heterogeneous Catalysis written by Joost Frenken and published by Springer. This book was released on 2016-12-26 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is devoted to the emerging field of techniques for visualizing atomic-scale properties of active catalysts under actual working conditions, i.e. high gas pressures and high temperatures. It explains how to understand these observations in terms of the surface structures and dynamics and their detailed interplay with the gas phase. This provides an important new link between fundamental surface physics and chemistry, and applied catalysis. The book explains the motivation and the necessity of operando studies, and positions these with respect to the more traditional low-pressure investigations on the one hand and the reality of industrial catalysis on the other. The last decade has witnessed a rapid development of new experimental and theoretical tools for operando studies of heterogeneous catalysis. The book has a strong emphasis on the new techniques and illustrates how the challenges introduced by the harsh, operando conditions are faced for each of these new tools. Therefore, one can also read this book as a collection of recipes for the development of operando instruments. At present, the number of scientific results obtained under operando conditions is still limited and mostly focused on a simple test reaction, the catalytic oxidation of CO. This reaction thus forms a natural binding element between the chapters, linking the demonstrations of new techniques, and also connecting the theoretical and experimental studies. Some first results on other reactions are also presented. If there is one thing that can be concluded already in this early stage, it is that the catalytic conditions themselves can have dramatic effects on the structure and composition of the surfaces of catalysts, which, in turn can greatly affect the mechanisms, the activity, and the selectivity of the chemical reactions that they catalyze.