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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

The papermaking properties of highly purified pulps.

Probst, T. Richard (Thomas Richard) 01 January 1939 (has links)
No description available.
2

Linkages between glucose and mannose in slash pine alpha-cellulose

Anthis, Austin F. (Austin Forrest) 01 January 1956 (has links)
No description available.
3

OXYGEN ISOTOPE ANALYSIS IN TREE-RINGS OF PTEROCAROUS ANGOLENSIS GROWING IN ZIMBABWE

McLeran, Kerry 01 May 2013 (has links)
My study was designed to identify the relationships between climate variables, such as precipitation and temperature, and δ 18 O values of tree ring &alpha-cellulose extracted from exactly dated tree rings of Pterocarpus angolensis growing in the arid to semiarid Mzola region of western Zimbabwe. This species is known to be sensitive to seasonal variation in rainfall. In this region, the wet season occurs during the austral summer from mid November to early April followed by a dry winter season from around June through October. Overall, the total annual rainfall exhibits a high degree of spatial and temporal variation with a mean of less than 600 mm per year. I applied the Modified Brendel technique to isolate &alpha-cellulose from raw wood samples extracted from two P. angolensis trees and measured the α-cellulose δ 18 O values using continuous flow isotope ratio mass spectrometry. I developed a 30-year (1955-1984) &alpha-cellulose δ 18 O chronology and correlated it with tree-ring width, meteoric water δ 18 O values, monthly and seasonal precipitation totals, and mean seasonal temperature. The δ 18 O values of meteoric water for this region were obtained from the Global Network of Isotopes in Precipitation (GNIP) and correlated with the δ 18 O values of tree ring &alpha-cellulose. The strongest correlations were observed between &alpha-cellulose δ 18 O values and February total precipitation (r = -0.49, p = 0.006) and to a lesser degree total wet season (NDJFMA) precipitation, In particular, unusually rainy wet seasons were significantly correlated (r = -0.79, P = 0.007) with &alpha-cellulose δ 18 O. This relationship is consistent with 18 O-depleted values measured in summer precipitation during periods of high rainfall, which is most likely the result of the isotopic amount effect reported in tropical regions. I also identified a positive correlation (r = 0.49, p = 0.03) between &alpha-cellulose δ 18 O and the δ 18 O values of meteoric water, and investigated the possibility of an isotopic temperature effect for δ 18 O in meteoric water, which also may be reflected in the δ 18 O values in tree ring &alpha-cellulose. The strongest correlation with mean temperature was observed during the wet summer season (r = 0.56, p = 0.01). My results suggest that the δ 18 O values of P. angolensis tree rings can be used as natural indicators of paleoclimate in southern Africa.
4

Acetolysis products of slash pine alpha-cellulose studied by chromatographic methods

Leech, John Graydon 06 1900 (has links)
No description available.

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