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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Modelling secondary organic aerosol formation :from chemical mechanistic modelling to empirical modelling

Singh Peterson, Lila, Physics, Faculty of Science, UNSW January 2007 (has links)
The work presented in this thesis is primarily concerned with modelling the formation of secondary organic aerosols (SOAs). SOAs cannot easily be measured with direct analytical chemical methods; indirect methods like applying organic carbon to elemental carbon ratios and utilising computer models have been employed to provide an estimate of the SOA mass concentrations in ambient air. The five models presented in this work were either developed or assessed using environmental chamber data. Chamber experiments were undertaken using initial isoprene concentrations in the range of 22 ppb to 343 ppb, with the reactive organic carbon (ROC) to NOx ratios in the range of 2.0 to about 18. Chamber experiments were also performed for the a-pinene / NOx system with initial a-pinene concentrations ranging from 79 ppb to 225 ppb, with ROC/NOx ratios varying from 5.5 to about 41. All of the experiments were performed without the addition of propene or seed aerosol. Background aerosol levels were very low for the experiments presented in the thesis and so homogeneous nucleation processes were considered to occur in the chamber in addition to absorption and oligomerisation formation processes. Initial nucleation events resulting from the photooxidation of isoprene could be detected once the aerosol diameter was greater than 12 nm. In the a-pinene system,new particles formed via homogeneous nucleation processes were detectable in the 100-200nm diameter range. The models presented range in complexity from the near explicit Master Chemical Mechanism to an empirical model whose key feature is its simplicity. The mechanistic model provides an insight into the SOA formation pathways and the influence of varying the initial experimental conditions and the duration of photooxidation on the simulated SOA composition. The aim of the empirical model is to simulate the SOA mass concentration produced during a chamber experiment. The development of the model is intentionally simple so that it can be applied to any hydrocarbon and has been applied successfully to isoprene and a-pinene chamber experiments. In this way, the empirical model is presented as an alternative approach to predicting the temporal variation in SOA mass concentrations. An analysis of the partitioning absorption models developed by Odum et al. (1996) and Hoffmann et al. (1997) has informed the development of the SOA module which has been coupled to a 3D atmospheric model. Embodied within the SOA module is the gas / aerosol partitioning theory which includes the model proposed initially by Pankow et al. (1994) and by Odum et al. (1996).
2

Environmental protection of geological monuments in South Australia /

Swart, Rosemary Helen. January 1992 (has links) (PDF)
Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1993? / Includes bibliographical references (leaves 90-98).
3

Geology of the southernmost Deschutes basin, Tumalo quadrangle, Deschutes County, Oregon /

McDannel, Angela K. January 1989 (has links)
Thesis (M.S.)--Oregon State University, 1989. / Typescript (photocopy). Folded map in pocket. Includes mounted photographs. Includes bibliographical references. Also available online.
4

A study of the basal Cherokee in the Rolla area

Murphy, Thomas Daniel, January 1929 (has links) (PDF)
Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1929. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed October 7, 2009) Includes bibliographical references.
5

Depositional environments, basin evolution and tectonic significance of the Eocene Chumstick Formation, Cascade Range, Washington /

Evans, James Erwin. January 1988 (has links)
Thesis (Ph. D.)--University of Washington, 1988. / Vita. Bibliography: leaves [236]-254.
6

Modeling natural fracture networks establishing the groundwork for flow simulation at Teapot Dome, Wyoming /

Smith, Valerie L. January 2008 (has links)
Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains ix, 147 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references.
7

RED CHERT-CLAST CONGLOMERATE IN THE EARP FORMATION (PENNSYLVANIAN-PERMIAN), SOUTHEASTERN ARIZONA: STRATIGRAPHY, SEDIMENTOLOGY, AND TECTONIC SIGNIFICANCE

Armin, Richard Alan January 1986 (has links)
A single interval of red chert-clast conglomerate and associated strata (RCC/CRCC interval) occur within the Earp Formation (pennsylvanian-Permian) at many localities in southeastern Arizona, southwestern New Mexico, and northern Mexico, and record a middle Wolfcampian erosional event in the Pedregosa shelf and northern basin. The RCC and CRCC intervals are respective proximal and distal braidplain deposits, in contrast to the Earp Formation exclusive of the RCC/CRCC interval, which consists of interbedded carbonate and fine-grained siliciclastic strata that were deposited in mostly shallow- and marginalmarine environments. Deposition of stream channel, gravel bar, and interfluvial shale beds of the RCC/CRCC interval occurred on a broad, low-lying surface with negligible local topography. Paleocurrents were generally southward. Biostratigraphic evidence suggests that lower Wolfcampian strata below the RCC/CRCC interval were beveled northward. Much of the chert present- in the RCC/CRCC interval is probably residual material from the beveled strata, as well as from a region just north of the Pedregosa shelf. The evolution of the Pedregosa shelf and northern basin during depoSition of the Earp Formation is illuminated by identification of facies belts for three time intervals: (1) restricted shelf, inner shelf, and open-marine shelf facies belts during Virgilian through early Wolfcampian ttme, (2) proximal and distal braidplain facies belts during middle Wolfcampian time, and (3) restricted shelf, estuarine-marginal marine, and tidal-flat facies belts during middle through late(?) Wolfcampian time . The middle Wolfcampian erosional event caxnpanying the deposition of the RCC/CRCC interval was probably related to the Ouachita orogeny. Stratigraphic evidence suggests that the southern Pedregosa basin in Chihuahua, Mexico, evolved rapidly to a deep foreland basin during early or middle Wolfcarrpian tine because of downflexure under northward overthrusts during the Ouachita orogeny. Flexural subsidence of the Pedregosa foreland basin was accanpanied by peripheral forebulging, causing subaerial exposure of large parts of the Pedregosa shelf and northern basin. Deposition of the FCC/CFfX interval probably occurred on the subaerially exposed forebulge. Flexural mxlels predicting the deflection of the lithosphere under isostatic thrust and secliIrent loads agree satisfactorily with the forebulge concept for the origin of the RCC/CRCC interval.
8

Stratigraphy and architecture of a coarse-grained deep-water system within the Cretaceous Cerro Toto formation, Silla Syncline area, southern Chile

Bozetti, Guilherme January 2017 (has links)
The Upper Cretaceous Cerro Toro Formation, southern Chile, is characterised by thinbedded turbidites that envelope a series of coarse-grained, confined slope complex systems, interpreted as part of the Lago Sofia Member. This deep-water slope system overlies basin floor sheets of the Punta Barrosa Formation, and is overlain by the sand-filled slope channels of the Tres Pasos Formation. Particularly distinctive beds, known as TEDs (transitional event deposits), are up to 40 m thick, laterally extensive, have prominent fluted bases, and have a vertical fabric starting with (1) a thin, inversely-graded, clast-supported base; then (2) a normally-graded and clastsupported interval; (3) an increasingly sand and clay matrix-supported conglomerate, with (4) a progressive upwards increase in matrix and normally grading, both in the floating gravel clast and matrix grain sizes, towards the top; and (5) a co-genetic sandstone on top. In the Cerro Toro formation, these TEDs tend to occur as multiple beds in the initial phases of deposition of each channel complex system. The TEDs are highly aggradational, slightly more amalgamated in the channel-axis, and more layered towards the margins. The fabric of these spectacular event beds is described in some detail from measured sections, combined with petrographic analysis and high-resolution field mapping. The 4 km x 200 m channel systems are contained within topographically irregular bathymetric lows that formed sediment pathways, interpreted to be either the result of slope deformation, or contained by poorly preserved, tectonically disrupted or slumped external levee. Syn-sedimentary tectonism is interpreted to be responsible for sharp changes in the system's architecture from channels to ponds, marked by a sharp change in lithofacies from dominantly conglomerates to dominantly sandstones. A refined architectural analysis is proposed, focusing on the recurrent pattern of at least 5 cycles of conglomerate-filled channel systems – ponded sheet sandstones.
9

A stratigraphic and sedimentary analysis of the Purslane Formation of western Maryland

O'Connell, Jeffrey I. January 2002 (has links)
Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains ix, 298 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 104-113).
10

Stratigraphy and sedimentology of the middle eocene Cowlitz Formation and adjacent sedimentary and volcanic units in the Longview-Kelso area, southwest Washington /

McCutcheon, Mark S. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2004. / Includes maps in pocket. Typescript (photocopy). Includes bibliographical references (leaves 306-314). Also available online.

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