Download or read book Understanding Atmospheric Aerosol Reactivity Using Morphology dependent Stimulated Raman Scattering Final Technical Report written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The long term focus of this research was to develop an experimental technique which can be used to characterize and monitor laboratory generated aerosol particles. The interest in aerosols developed because recent field studies have shown that heterogeneous chemistry is contributing far more to global atmospheric balance and climate change than had been previously thought. There became a pressing need for the kinetics of these systems to be well understood, but this presented a challenge for atmospheric aerosol systems that could not be studied using conventional surface science techniques. This is because they are comprised, for the most part, of volatile material. A new experimental technique, capable of monitoring surface species in these systems, needed to be developed. The author felt that morphology-dependent stimulated Raman scattering, MDSRS, fit the bill quite well.
Download or read book Characterization of Gas aerosol Interaction Kinetics Using Morphology Dependent Stimulated Raman Scattering Final Technical Report written by and published by . This book was released on 1992 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: A research program on the influence of aerosol surface structure on the kinetics of gas-aerosol interactions is proposed. The experiments involve measuring changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol. Aerosols with differing surface properties will be generated by changing the composition and/or temperature of the material making up the aerosol. Kinetic data generated can be used directly in atmospheric modelling calculations. The surface structure of the aerosol will be measured, both before and after reaction, using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Information about the detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during the course of the reaction. Studies will focus on the condensation and oxidation of sulfur species (sulfur dioxide and dimethyl sulfide) on water aerosols.
Download or read book Characterization of Gas aerosol Interaction Kinetics Using Morphology Dependent Stimulated Raman Scattering written by and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is aimed at characterizing the influence of aerosol surface structure on the kinetics of gas-aerosol interactions. Changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol are measured with aerosols having different surface properties due to the composition and/or temperature of the material making up the aerosol. The kinetic data generated can be used directly in atmospheric modeling calculations. The surface structure of the aerosol is using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during, the course of the reaction. This dynamics information can be used to generate kinetic data for systems which are similar in nature to those studied, but are not amenable to laboratory investigation. We show here that increased MDSRS sensitivity is achieved by using an excitation laser source that has a narrow linewidth and we have been able to detect sulfate anion concentrations much lower than previously reported. We have shown that the linewidth of the MDSRS mode excited in a droplet is limited by the laser linewidth. This is a positive result for it eases our ability to quantify the MDSRS gain equation. This result also suggests that MDSRS signal size should be independent of droplet size, and preliminary experiments confirm this hypothesis.
Download or read book The Development of Morphology Dependent Stimulated Raman Scattering MDSRS and Its Application to the Detection of Sulfate in Aerosol Particles written by Alan Scott Olson and published by . This book was released on 1993 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Gas aerosol Interaction Kinetics Using Morphology Dependent Stimulated Raman Scattering 1992 Annual Summary written by and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is aimed at characterizing the influence of aerosol surface structure on the kinetics of gas-aerosol interactions. Changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol are measured with aerosols having different surface properties due to the composition and/or temperature of the material making up the aerosol. The kinetic data generated can be used directly in atmospheric modeling calculations. The surface structure of the aerosol is using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during, the course of the reaction. This dynamics information can be used to generate kinetic data for systems which are similar in nature to those studied, but are not amenable to laboratory investigation. We show here that increased MDSRS sensitivity is achieved by using an excitation laser source that has a narrow linewidth and we have been able to detect sulfate anion concentrations much lower than previously reported. We have shown that the linewidth of the MDSRS mode excited in a droplet is limited by the laser linewidth. This is a positive result for it eases our ability to quantify the MDSRS gain equation. This result also suggests that MDSRS signal size should be independent of droplet size, and preliminary experiments confirm this hypothesis.
Download or read book Fundamentals and Applications in Aerosol Spectroscopy written by Ruth Signorell and published by CRC Press. This book was released on 2010-12-20 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Helping you better understand the processes, instruments, and methods of aerosol spectroscopy, Fundamentals and Applications in Aerosol Spectroscopy provides an overview of the state of the art in this rapidly developing field. It covers fundamental aspects of aerosol spectroscopy, applications to atmospherically and astronomically relevant problem
Download or read book Analytical Chemistry of Aerosols written by Kvetoslav R. Spurny and published by CRC Press. This book was released on 2017-11-22 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: Until the 1980s, researchers studied and measured only the physical properties of aerosols. Since the 80s, however, interest in the physicochemcal properties of aerosols has grown tremendously. Scientists in environmental hygiene, medicine, and toxicology have recognized the importance held by the chemical composition and properties of aerosols and the interactions of inhaled, "bad" aerosols. This book offers the first comprehensive treatment of modern aerosol analytical methods, sampling and separation procedures, and environmental applications, and offers critical reviews of the latest literature. This important field has developed rapidly in the last 15 years, but until now, no book effectively summarized or analyzed the existing research. Analytical Chemistry of Aerosols reviews procedures, techniques, and trends in the measurement and analysis of atmospheric aerosols. With contributions from acknowledged, international experts, the book discusses various methods of bulk analysis, single particle analysis, and the analysis of special aerosol systems, including fibrous and bacterial aerosols.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1993 with total page 1834 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Measurements of the Properties of Aerosol Particles written by Emma Tackman and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosol particles are a diverse class of materials that permeate the atmosphere with implications for global climate and human health. Atmospheric aerosols are released into the environment from many sources and continue to undergo atmospheric processing which introduces further variation into particle populations. This surfeit of sources and atmospheric trajectories leads to a wide variety in the properties in aerosol particles such as composition, shape, size, morphology, and reactivity. The methods measuring properties of aerosol particles is itself an important and developing field of study with direct applications in bettering our understanding of aerosol behaviors and atmospheric chemical systems. This work presents a critical analysis of existing microscopy-based measurements and provides new methods, applications, and recommendations for improving the assessment of aerosol properties. Chemical properties of aerosol particles include aqueous particle acidity and the O:C ratio of organic constituents. A new method for measuring the internal pH of aqueous aerosol microdroplets was developed and presented here using carbon quantum dots as a pH sensitive fluorophore. This technique was validated using a complex organic mixture representing various functional groups found in atmospheric organic material. The influence of organic O:C ratio on phase separation for proxy organic/inorganic mixed aerosol particles was assessed for microdroplets and nanoparticles. For optical microscope experiments, sucrose was added to organic/inorganic mixtures to systematically increase the O:C ratio of the system and was observed to suppress phase separation. Similarly, particles made up of combinations of carboxylic acids at particular O:C ratios and inorganic salts are analyzed using TEM for size dependence of phase separation at the nanoscale. Generally, large particles are able to phase separate while small particles remain homogeneous, or well mixed, and the transition region between the two regimes was examined. TEM is used in several studies to consider aerosol particle spreading and morphology at atmospherically relevant sizes. Inorganic particles were found to spread along the surface of a substrate. Particles with an organic coating also spread on the substrate but additionally lost volume, possibly due to outgassing of residual volatile species in storage or physical deformation during the impaction process. Results were compared to measurements of the same particles suspended in a gas flow and sizing discrepancies between the two methods were found, mostly attributed to the presence of a substrate in microscope assays. Further, the influence of generation parameters on the final morphologies of particles was determined for particles made under low and high relative humidity conditions with wet and dry seed particles. Wet seeds were found to restructure due to humidity cycling and spread less on the surface than dry seeds, while wet and dry coated particles were influenced similarly by the impaction process. Wet seeded organic particles also showed a new textured morphology, emphasizing the utility of microscope measurements of individual aerosol particles.
Download or read book Acid Precipitation written by and published by . This book was released on 1993-07 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stimulated Raman Scattering Microscopy written by Ji-Xin Cheng and published by Elsevier. This book was released on 2021-12-04 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stimulated Raman Scattering Microscopy: Techniques and Applications describes innovations in instrumentation, data science, chemical probe development, and various applications enabled by a state-of-the-art stimulated Raman scattering (SRS) microscope. Beginning by introducing the history of SRS, this book is composed of seven parts in depth including instrumentation strategies that have pushed the physical limits of SRS microscopy, vibrational probes (which increased the SRS imaging functionality), data science methods, and recent efforts in miniaturization. This rapidly growing field needs a comprehensive resource that brings together the current knowledge on the topic, and this book does just that. Researchers who need to know the requirements for all aspects of the instrumentation as well as the requirements of different imaging applications (such as different types of biological tissue) will benefit enormously from the examples of successful demonstrations of SRS imaging in the book. Led by Editor-in-Chief Ji-Xin Cheng, a pioneer in coherent Raman scattering microscopy, the editorial team has brought together various experts on each aspect of SRS imaging from around the world to provide an authoritative guide to this increasingly important imaging technique. This book is a comprehensive reference for researchers, faculty, postdoctoral researchers, and engineers. Includes every aspect from theoretic reviews of SRS spectroscopy to innovations in instrumentation and current applications of SRS microscopy Provides copious visual elements that illustrate key information, such as SRS images of various biological samples and instrument diagrams and schematics Edited by leading experts of SRS microscopy, with each chapter written by experts in their given topics
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993-06 with total page 1392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preprints of Papers written by American Chemical Society. Division of Environmental Chemistry and published by . This book was released on 1995 with total page 834 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index Keyword A L written by and published by . This book was released on 1985 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
