Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 15 of 15 for “"halocarbons"”.
-
Emission of biogenic halocarbons in temperate and tropical coastal zones
Biogenically-produced halocarbons play an important role in regional and global biogeochemical processes. These compounds are short-lived (lifetimes <6 months) and so have temporal and spatial variability in their atmospheric distributions. Marine regions, in particular coastlines, have been …
-
A two-dimensional global dispersion model applied to several halocarbons
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1983.
-
A Novel Mass Spectrometer for Atmospheric Measurements & Halocarbons During the CARIBIC and SAMBBA Aircraft Campaigns
Identification and monitoring of halocarbons in the atmosphere remains important for the purposes of regulation and prediction of stratospheric ozone depletion. Measurements of these and other compounds have created a demand for techniques that improve the number of atmospheric compounds …
-
The municipal solid waste landfill as a source of Montreal Protocol-restricted halocarbons in the United States and United Kingdom
… emissions of Montreal Protocol-restricted halocarbons (MPGs) over the coming decades. The prediction of emissions has become difficult as global production of MPGs has rapidly declined establishing "banks" (MPGs which have been produced but not yet released) as the main emission sources. …
-
Transport and Distribution of the Short-Lived Halocarbons in the Tropical Tropopause Layer in the Pacific Ocean: the Role of Convection
… layer (TTL) in the Pacific Ocean. Short-lived halocarbons are one of the major groups of the ozone depleting substances as they provide a source for the active halogens which decrease ozone in the atmosphere. The TTL serves as the primary gateway of tropospheric air to enter the stratosphere. …
-
The effects of elevated CO2 and ocean acidification on the production of marine biogenic trace gases
… influence on biogeochemical climate feedbacks. Halocarbons are also important biogenic trace gases which undergo atmospheric photochemical degradation, releasing halide radicals to participate in atmospheric ozone cycling, and transfer halogens from sea to land. Evidence is presented from a …
-
Temporal variation, regional sources, and removal processes of volatile organic compounds in New England
… of nonmethane hydrocarbons (NMHCs), selected halocarbons, and alkyl nitrates using measurements from canister samples collected at Thompson Farm in Durham, NH throughout January 2004-February 2008. Several anthropogenic and biogenic sources of NMHCs and halocarbons were identified based on …
-
Environmental Applications of Ultrasound
… hydrodehalogenation of aliphatic and aromatic halocarbons at low temperatures (T = 200--300°C). Both catalysts were selective, active, and stable for all substrates tested. The HDH of substrates bearing aliphatic C-Cl bonds occurs faster than those with aryl C-Cl bonds. Characterization of …
-
Atmospheric volatile organic compound measurements: Distributions and effects on air quality in coastal marine, rural and remote continental environments
… for a large suite of nonmethane hydrocarbons, halocarbons, and alkyl nitrates, from part per billion by volume (ppbv) to part per trillion by volume (pptv) levels. The measurement precision for most gases ranged from 1-10%.</p><p>Results from two subsequent field campaigns (2002 and 2003) …
-
Measurement and deduction of emissions of short-lived atmospheric organo-chloride compounds
… halogenated organics have centered on long lived halocarbons due to their effect on stratospheric ozone. Now that controls have been put in place to curb emissions of longer lived halocarbons through the Montreal Protocol, and speculation about the safety of many short-lived chlorinated organic …
-
Iodine in sea ice and the polar atmosphere.
… the Arctic environment. High concentrations of halocarbons were measured in the brine of sea ice, with respect to the water below, in the Arctic Ocean. High atmospheric halocarbon mixing ratios and flux calculations have demonstrated the effect on the atmosphere above. In the Canadian …
-
Characterization of resistance to halogenated aromatic hydrocarbons in a population of Fundulus heteroclitus from a marine superfund site
New Bedford Harbor (NBH), MA, is contaminated with halogenated aromatic hydrocarbons HAH including some potent aryl hydrocarbon receptor AhR agonists. To determine if Fundulus heterocitus from NBH have developed resistance to HAll, we examined the inducibility of cytochrome P4501A1 CYP1A1 in fish …
-
Reaction chemistry of C₁ hydrocarbon fragments and oxygenates on Cr₂O₃ (101̅2)
The reactions of iodomethane, diiodomethane, and formaldehyde over stoichiometric, O-terminated, and Cl-terminated α-Cr₂O₃ surfaces, were studied by thermal desorption spectroscopy. Adsorbed formaldehyde forms dioxymethylene species on the nearly-stoichiometric surface that react primarily above …
-
Mechanisms of action for aryl hydrocarbon receptor ligands in the PLHC-1 cell line
Aryl hydrocarbon receptor (AHR) expression and activity was characterized in the teleost hepatoma cell line, PLHC-1. This work was carried out in order to gain insights into mechanisms of halogenated aromatic hydrocarbon (HAH) toxicity. The results improve our ability to characterize the risks …
-
Reactions of Halogenated Ethylenes on the α-Cr₂O₃ (101̅2) Surface
The thermally induced reaction of halogenated ethylenes on the α-Cr₂O₃ (101̅2) single crystal surface results in the formation of gas phase hydrocarbons including acetylene, ethylene, butadiene, and dihydrogen, and deposition of surface chlorine adatoms. No surface carbon or combustion products are …