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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.
151

Laser ablation of modern human cementum: the examination of trace element profiles

Lefever, Lisa 07 April 2010 (has links)
This study used LA-ICP-MS on a documented sample of modern teeth to sample from a continuous line across the cementum increments thus creating a temporal line graph of the elemental composition against distance. The knowledge of cementum was extended through (1) a more complete elemental composition analysis and (2) the relation of element distribution to the ultrastructure structure throughout the life of a tooth. This study was exploratory and demonstrated that lead, zinc, mercury, and barium follow the same general line of changes, and most likely represent changes in health and exposure to these metals in the general environment. Copper, manganese and vanadium varied very little. Technological limitations prevented the examination of element levels in any one annulation.
152

Remediation of trace element-contaminated groundwater and soils using redox-sorption and phytoextraction techniques

Murata, Alison Patricia 08 January 2013 (has links)
Remediation of trace element-contaminated sites must consider both the nature of the contaminants and environmental surroundings. This thesis examined treatments for two contamination scenarios. The first study characterized chromium dynamics during the redox-sorption treatment of aqueous hexavalent chromium with the reducing agent sodium dithionite and two iron oxides. Results showed that chromium was successfully removed from solution by precipitation and sorption. The iron oxide derived from ferric chloride had a greater sorption capacity for hexavalent chromium than the oxide derived from ferrous chloride. The second study examined the phytoextraction treatment of soils contaminated with multiple trace elements. Deschampsia caespitosa plants had better early growth in the contaminated high-organic matter soil than three Brassica species. However, D. caespitosa plants did not take up sufficient amounts of trace elements during the study to be considered useful for short-term phytoextraction. These findings are applicable to the development of effective trace element remediation methods.
153

LATEST QUATERNARY PALEOCLIMATE RECONSTRUCTION UTILIZING STABLE ISOTOPIC AND TRACE ELEMENT PROXIES IN A STALAGMITE FROM CULVERSON CREEK CAVE, WEST VIRGINIA

Gilbert, Ashley Nicole 01 January 2010 (has links)
A reconstruction of regional climate variability in southern West Virginia that spans the last glacial/interglacial transition is presented. Paleoclimate interpretations obtained from the 50-cm long stalagmite provide key insights regarding the timing, magnitude, and forcing mechanisms responsible for past climate variability. Stable isotopic (δ18O and δ13C) and trace element (Ba, Sr, Mg) signatures from samples contiguously milled along the growth-axis of a 230Th-dated stalagmite which grew between approximately 20 and 5 thousand years before present (kyr BP) provide critical constraints for above-cave mean annual temperature, seasonality of moisture mean annual precipitation, and potential vegetation shifts. Specifically, the stalagmite record reveals subcentennial-scale variations in the proxy records, and strong multimillennial-scale features that correlate to well-known patterns of sea-surface variability in the North Atlantic Ocean (i.e., Bond cycles). The large-scale glacial/interglacial transition is sufficiently resolved to show that regional climate changes largely paralleled climatic transitions preserved in low-latitude (Chinese monsoon records; Cariaco Basin) and high-latitude (Greenland Ice Sheet) paleo-archives. However, the Younger Dryas interval in the south-central Appalachian Mountains is not as prominent a feature as in other records.
154

Laser ablation of modern human cementum: the examination of trace element profiles

Lefever, Lisa 07 April 2010 (has links)
This study used LA-ICP-MS on a documented sample of modern teeth to sample from a continuous line across the cementum increments thus creating a temporal line graph of the elemental composition against distance. The knowledge of cementum was extended through (1) a more complete elemental composition analysis and (2) the relation of element distribution to the ultrastructure structure throughout the life of a tooth. This study was exploratory and demonstrated that lead, zinc, mercury, and barium follow the same general line of changes, and most likely represent changes in health and exposure to these metals in the general environment. Copper, manganese and vanadium varied very little. Technological limitations prevented the examination of element levels in any one annulation.
155

Remediation of trace element-contaminated groundwater and soils using redox-sorption and phytoextraction techniques

Murata, Alison Patricia 08 January 2013 (has links)
Remediation of trace element-contaminated sites must consider both the nature of the contaminants and environmental surroundings. This thesis examined treatments for two contamination scenarios. The first study characterized chromium dynamics during the redox-sorption treatment of aqueous hexavalent chromium with the reducing agent sodium dithionite and two iron oxides. Results showed that chromium was successfully removed from solution by precipitation and sorption. The iron oxide derived from ferric chloride had a greater sorption capacity for hexavalent chromium than the oxide derived from ferrous chloride. The second study examined the phytoextraction treatment of soils contaminated with multiple trace elements. Deschampsia caespitosa plants had better early growth in the contaminated high-organic matter soil than three Brassica species. However, D. caespitosa plants did not take up sufficient amounts of trace elements during the study to be considered useful for short-term phytoextraction. These findings are applicable to the development of effective trace element remediation methods.
156

Trace element partition in sulphides, Noranda, Quebec.

Beaton, William Douglas. January 1970 (has links)
No description available.
157

X-ray based tree ring analyses /

Lindeberg, Johan, January 2004 (has links) (PDF)
Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 5 uppsatser.
158

Trace metals in urban soils : Stockholm as a case study /

Linde, Mats, January 2005 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.
159

Elemental composition of fine particles : exposure in the general population and influence from different sources /

Molnár, Peter, January 2007 (has links)
Diss. (sammanfattning) Göteborg : Göteborgs universitet , 2007. / Härtill 4 uppsatser.
160

Performance of water recycling technologies

Al-rifai, Jawad Hilmi. January 2008 (has links)
Thesis (Ph.D.)--University of Wollongong, 2008. / Typescript. Includes bibliographical references.

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