Download or read book Development of Fiber laser based Laser induced Fluorescence for Detection of SO2 written by and published by . This book was released on 1998 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gaining a quantitative understanding of many aspects of the earth's climate system requires development of new detection methods for key atmospheric species and their incorporation into chemical sensors with high sensitivity, specificity, and time response. The authors have initiated a research program to develop these new chemical-sensing capabilities. The species they have targeted initially are oxides of nitrogen and sulfur, specifically NO and S02 These molecules play a central role in the earth's climate, and anthropogenic activities (primarily fossil-fuel combustion) are the dominant source of both species. They are exploring the use of single-mode fiber lasers and amplifiers as compact, lightweight sources of tunable, narrow-bandwidth, deep-UV radiation. They have also begun spectroscopic studies to optimize UV laser-induced fluorescence for detection of S02 with high sensitivity and specificity.
Download or read book Development of Bio photonic Sensor Based on Laser induced Fluorescence written by Chan Kyu Kim and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) has been shown to be potentially useful for identifying microorganisms in real time. It is a selective and sensitive technique because the excitation is performed at one wavelength while the emission is monitored at longer wavelengths so that background from the excitation source can be eliminated. This specialized optical property of LIF can be applied to development of an optical sensor capable of quickly, non-invasively, and quantitatively probing complex biochemical transformations in microorganisms. Various bio-photonic optical fiber sensors based on laser-induced fluorescence (LIF) spectroscopy were developed as diagnostic tools for microorganisms. In the first phase, the enhancement of the sensitivity and selectivity of the optical sensor system focused on diagnosis of human breast cancer cell lines and Azotobacter vinelandii (an aerobic soil-dwelling organism). Auto-fluorescence spectra from human breast cancer cell lines and Azotobacter vinelandii corresponding to different growth environments were investigated. Then, the study has expanded to include the use of gold nanoparticles for specific DNA detection. The use of gold nanoparticles opens a door into construction of a compact, highly specific, inexpensive and user-friendly optical fiber senor for specific DNA detection. An optical fiber laser-induced fluorescence (LIF) sensor based has been developed to detect single-strand (ss) DNA hybridization at the femtomolar level. Effects of various experimental parameters and configuration were investigated in order to optimize sensor performance and miniaturize sensor size.
Download or read book UV Laser Induced Fluorescence Detection of the Atmospheric Trace Gases NO SO2 CH2O written by Douglas Dale Davis and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Photofragmentation laser Induced Fluorescence PF LIF Laser Sensor for Detection of 2 4 6 trinitrotolue written by Gary Michael Boudreaux and published by . This book was released on 1997 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Two photon laser Induced Fluorescence Sensor for the Detection of Atmospheric OH Radicals written by John David Bradshaw and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Development and Evaluation of a Laser induced Fluorescence Experiment for the Detection of Trace Compounds in Water Using a Tuneable UV OPO System written by and published by . This book was released on 1996 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Applications of Laser Enhanced Ionization Laser Induced Fluorescence and Photoionization Detection Systems for Trace Detection of Elements and Compounds of Environmental and Biological Significance written by Seth Aaron Elwood and published by . This book was released on 2001 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Laser induced Fluorescence to Quantify In cylinder Fuel Wall Films written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Application of a Photofragmentation laser induced Fluorescence Detection System for Atmospheric Nitrous Acid written by Michael Owen Rodgers and published by . This book was released on 1987 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Application of Infrared and Tracer based Planar Laser induced Fluorescence Imaging Diagnostics written by David A. Rothamer and published by . This book was released on 2007 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: IR-PLIF measurements of temperature and pressure are a new application of the technique. Initial IR-PLIF measurements focused on species concentrations of CO and CO2. The strong dependence of IR-PLIF signals on temperature and pressure indicated that IR-PLIF measurements of those quantities are possible.
Download or read book Development of a Two Photon laser Induced Fluorescence Technique for the Detection of Atmospheric OH Radicals written by John Bradshaw and published by . This book was released on 1990 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Mining Laws and Regulations Thereunder General Land Office April 1 1879 written by and published by . This book was released on with total page 28 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 . This book was released on 2011 with total page 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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book The Development of New Techniques in Infared and Laser induced Fluorescence Spectrometry written by Mark Alan Castles and published by . This book was released on 1986 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Development and Application of Laser induced Fluorescence for the Study of Magnetically Confined Plasmas written by Warren Wright and published by . This book was released on 1989 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
