A5060153301- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Spectroscopy and Laser Applications
- Atmospheric and Environmental Gas Dynamics
- Advanced X-ray Imaging Techniques
- Icing and De-icing Technologies
- Electron and X-Ray Spectroscopy Techniques
- Advanced Electron Microscopy Techniques and Applications
- Arctic and Antarctic ice dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Catalytic Processes in Materials Science
- Astro and Planetary Science
- Metal-Organic Frameworks: Synthesis and Applications
- nanoparticles nucleation surface interactions
- Indoor Air Quality and Microbial Exposure
- Astrophysics and Star Formation Studies
- Vehicle emissions and performance
- X-ray Diffraction in Crystallography
- Electrochemical Analysis and Applications
- Advancements in Photolithography Techniques
- Advanced Chemical Physics Studies
- Research Data Management Practices
- Advanced Nanomaterials in Catalysis
Lawrence Berkeley National Laboratory
2014-2023
Universidade do Estado do Rio de Janeiro
2022
Universidade Federal do Paraná
2022
University of California, Berkeley
2005-2018
Berkeley College
2014-2016
Laboratoire Ingénierie, Procédés, Aliments
2013
Conservatoire National des Arts et Métiers
2013
AgroParisTech
2013
Environmental Molecular Sciences Laboratory
2010
University of Würzburg
2010
The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. preliminary examination these samples shows that the nonvolatile portion is an unequilibrated assortment materials have both presolar solar system origin. contains abundance silicate grains are much larger than predictions interstellar grain models, many high-temperature minerals appear formed in inner regions nebula. Their presence a proves formation included...
Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution abundance composition. Some organics are similar, but not identical, to those interplanetary dust particles carbonaceous meteorites. A class of aromatic-poor organic material is also present. The rich oxygen nitrogen compared with meteoritic organics. Aromatic compounds present, the tend be relatively poorer aromatics than meteorites particles. presence deuterium nitrogen-15 excesses suggest that...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBond strengths of ethylene and acetyleneKent M. Ervin, Scott Gronert, S. E. Barlow, Mary K. Gilles, Alex G. Harrison, Veronica Bierbaum, Charles H. DePuy, W. C. Lineberger, Barney EllisonCite this: J. Am. Chem. Soc. 1990, 112, 15, 5750–5759Publication Date (Print):July 1, 1990Publication History Published online1 May 2002Published inissue 1 July 1990https://pubs.acs.org/doi/10.1021/ja00171a013https://doi.org/10.1021/ja00171a013research-articleACS...
A comprehensive dataset of microphysical and radiative properties aerosols clouds in the boundary layer vicinity Barrow, Alaska, was collected April 2008 during Indirect Semi-Direct Aerosol Campaign (ISDAC). ISDAC's primary aim to examine effects aerosols, including those generated by Asian wildfires, on that contain both liquid ice. ISDAC utilized Atmospheric Radiation Measurement Pro- gram's permanent observational facilities at Barrow specially deployed instruments measuring aerosol, ice...
Abstract The Observations and Modeling of the Green Ocean Amazon 2014–2015 (GoAmazon2014/5) experiment took place around urban region Manaus in central Amazonia across 2 years. pollution plume was used to study susceptibility gases, aerosols, clouds, rainfall human activities a tropical environment. Many aspects air quality, weather, terrestrial ecosystems, climate work differently tropics than more thoroughly studied temperate regions Earth. GoAmazon2014/5, cooperative project Brazil,...
Measurements of the oxygen K-edge X-ray absorption spectrum (XAS) aqueous sodium halide solutions demonstrate that ions significantly perturb electronic structure adjacent water molecules. The addition salts to engenders an increase in preedge intensity and a decrease postedge XAS, analogous those observed when increasing temperature pure water. main-edge feature exhibits unique behavior becomes more intense salt is added. Density functional theory calculations XAS indicate red shift...
Complementary methods of high-resolution mass spectrometry and microspectroscopy were utilized for molecular analysis secondary organic aerosol (SOA) generated from ozonolysis two structural monoterpene isomers: D-limonene SOA (LSOA) α-pinene (PSOA). The LSOA compounds readily formed adducts with Na(+) under electrospray ionization conditions, only a small fraction detected in the protonated form. In contrast, significant PSOA appeared form because their increased rigidity. Laboratory...
Abstract— Synchrotron‐based soft X‐ray micro‐analysis was performed on particles extracted from the Stardust aerogel collector in order to obtain detailed organic functional group information any solids captured as part of Principal Examination suite analyses for samples comet 81P/Wild 2. It is observed that cometary carbon present a number different manifestations and often intimately associated with silicates. Carbon absorption near edge structure (XANES) spectra reveal considerable...
We have developed an automated data analysis method for atmospheric particles using scanning transmission X-ray microscopy coupled with near edge fine structure spectroscopy (STXM/NEXAFS). This is applied to complex internally mixed submicrometer containing organic and inorganic material. Several algorithms were exploit NEXAFS spectral features in the energy range from 278 320 eV quantitative mapping of spatial distribution elemental carbon, potassium, noncarbonaceous elements composition....
Atmospheric aerosols can undergo phase transitions including liquid–liquid separation (LLPS) while responding to changes in the ambient relative humidity (RH). Here, we report results of chemical imaging experiments using environmental scanning electron microscopy (ESEM) and transmission X-ray (STXM) investigate LLPS micrometer-sized particles undergoing a full hydration-dehydration cycle. Internally mixed composed ammonium sulfate (AS) either: limonene secondary organic carbon (LSOC), α,...
Detailed chemical speciation of the dry residue particles from individual cloud droplets and interstitial aerosol collected during Marine Stratus Experiment (MASE) was performed using a combination complementary microanalysis techniques. Techniques include computer controlled scanning electron microscopy with energy dispersed analysis X rays (CCSEM/EDX), time‐of‐flight secondary ionization mass spectrometry (TOF‐SIMS), transmission X‐ray near edge absorption fine structure spectroscopy...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNegative ion photoelectron spectroscopy of halocarbene anions (HCF-, HCCl-, HCBr-, and HCI-); angular distributions neutral triplet excitation energiesMary K. Gilles, Kent M. Ervin, Joe Ho, W. C. LinebergerCite this: J. Phys. Chem. 1992, 96, 3, 1130–1141Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February 1992https://doi.org/10.1021/j100182a021RIGHTS & PERMISSIONSArticle...
Abstract. The occurrence of nonliquid and liquid physical states submicron atmospheric particulate matter (PM) downwind an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 IOP2) that took place the wet dry seasons GoAmazon2014/5 campaign. Air masses representing variable influences background conditions, pollution, regional- continental-scale biomass burning passed over research site. As air varied, particle rebound...
Heterogeneous ice nucleation is a physical chemistry process of critical relevance to range topics in the fundamental and applied sciences technologies. remains insufficiently understood, partially due lack experimental methods capable obtaining situ microscopic details formation over nucleating substrates or particles. We present observations events on kaolinite particles at nanoscale demonstrate capability direct tracking micro-spectroscopic characterization individual (INPs) an authentic...
This article presents an overview of recent advances in field and laboratory studies atmospheric particles formed processes environmental air-surface interactions. The overarching goal these is to advance predictive understanding particle composition, chemistry during aging, their impacts. diversity between chemical constituents lateral heterogeneity within individual adds the complexity surfaces. Once emitted, undergo transformation via aging that further modify complex composition. We...
Abstract. Carbonaceous aerosols are responsible for large uncertainties in climate models, degraded visibility, and adverse health effects. The Aerosols Radiative Effects Study (CARES) was designed to study carbonaceous the natural environment of Central Valley, California, learn more about their atmospheric formation aging. This paper presents results from spectro-microscopic measurements particles collected during CARES at time a pollution accumulation event (27–29 June 2010), when situ...
Abstract. Aerosol absorption is strongly dependent on the internal heterogeneity (mixing state) and morphology of individual particles containing black carbon (BC) other non-absorbing species. Here, we examine an extensive microscopic data set collected in California Central Valley during CARES 2010 field campaign. During a period high photochemical activity pollution buildup, particle mixing state were characterized using scanning transmission X-ray microscopy (STXM) at K-edge. Observations...
R. K. Talukdar, J. B. Burkholder, M. Hunter, Gilles, Roberts and A. Ravishankara, Chem. Soc., Faraday Trans., 1997, 93, 2797 DOI: 10.1039/A701781B
The carbon, nitrogen, and oxygen K-edge spectra were measured for aqueous solutions of glycine by total electron yield near-edge X-ray absorption fine structure (TEY NEXAFS) spectroscopy. bulk solution pH was systematically varied while maintaining a constant amino acid concentration. Spectra assigned through comparisons with both previous studies ab initio computed isolated molecules hydrated clusters. Nitrogen recorded at low moderate are nearly identical to those solid glycine, whereas...
Nighttime chemical evolution of aerosol and trace gases in a coal‐fired power plant plume was monitored with the Department Energy Grumman Gulfstream‐1 aircraft during 2002 New England Air Quality Study field campaign. Quasi‐Lagrangian sampling at increasing downwind distances processing times guided by constant‐volume balloon that released near sunset. While no evidence fly ash particles found, concentrations particulate organics, sulfate, nitrate were higher than background air. The...
Abstract. We use a Lagrangian dispersion model driven by mesoscale with four-dimensional data assimilation to simulate the of elemental carbon (EC) over region encompassing Mexico City and its surroundings. The was study domain for 2006 MAX-MEX experiment, which component MILAGRO campaign. results are used identify periods when biomass burning likely have had significant impact on concentrations at two sites, T1 T2, downwind city, emissions from Metropolitan Area (MCMA) were been more...
Airborne biological particles, such as fungal spores and pollen, are ubiquitous in the Earth's atmosphere may influence atmospheric environment climate, impacting air quality, cloud formation, radiation budget. The transformations of airborne at elevated relative humidity remain poorly understood their climatic role is uncertain. Using an environmental scanning electron microscope (ESEM), we observed rupturing Amazonian subsequent release submicrometer size fragments after exposure to high...