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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.
51

The klason lignin determination as applied to aspenwood with special reference to acid-soluble lignin

Busche, Louis Roy. January 1960 (has links) (PDF)
Thesis (Ph. D.)--Institute of Paper Chemistry, 1960. / Includes bibliographical references (p. 96-100).
52

A study of the phenolic and carbohydrate materials in the newly formed tissues of aspenwood

Sultze, Rolland Fred, January 1956 (has links) (PDF)
Thesis (Ph. D.)--Institute of Paper Chemistry, 1956. / Bibliography: leaves 93-108.
53

Modeling of carbon dioxide absorption using aqueous monoethanolamine, piperazine and promoted potassium carbonate

Plaza, Jorge Mario 27 June 2012 (has links)
Rigorous CO₂ absorption models were developed for aqueous 4.5 m K+/4.5 m PZ, monoethanolamine (7m - 9m), and piperazine (8m) in Aspen Plus® RateSepTM. The 4.5 m K+/4.5 m PZ model uses the Hilliard thermodynamic representation and kinetics based on work by Chen. The MEA (Phoenix) and PZ (5deMayo) models incorporate new data for partial pressure of CO₂ vs. loading and kinetics from wetted wall column data. They use reduced reaction sets based on the more relevant species present at the expected operating loading. Kinetics were regressed to match reported carbon dioxide flux data using a wetted wall column (WWC). Density and viscosity were satisfactorily regressed to match newly obtained experimental data. The activity coefficient of CO₂ was also regressed to include newly obtained CO₂ solvent solubility data. The models were reconciled and validated using pilot plant data obtained from five campaigns conducted at the Pickle Research Center. Performance was matched within 10% of NTU for most runs. Temperature profiles are adequately represented in all campaigns. The calculated temperature profiles showed the effect of the L/G on the location and magnitude of the temperature bulge. As the L/G is increased the temperature bulge moves from near the top of the column towards the bottom and its magnitude decreases. Performance improvement due to intercooling was validated across the campaigns that evaluated this process option. Absorber intercooling was studied using various solvent rates (Lmin, 1.1 Lmin and 1.2 Lmin). It is most effective at the critical L/G where the temperature bulge without intercooling is in the middle of the column. In this case it will allow for higher absorption by reducing the magnitude of the bulge temperature. The volume of packing to get 90% removal with L/Lmin =1.1 at the critical L/G is reduced by 30% for 8m PZ. For MEA and a solvent flow rate of 1.1 Lmin packing volume is increased with intercooling at constant L/G. This increase is compensated by higher solvent loadings that suggest lower stripping energy requirements. The critical L/G is 4.3 for 8m PZ, 6.9 for 9m MEA and 4.1 for K+/PZ. / text
54

Giberelinų ir jų biosintezės inhibitorių poveikis drebulės (Populus tremula L.) eksplantų vystymuisi in vitro kultūroje / Effect of gibberellins and their biosynthesis inhibitors on development of aspen (Populus tremula L.) explant in in vitro culture

Barčaitė, Laura 28 June 2008 (has links)
Šio magistrinio darbo tikslas buvo ištirti giberelinų ir jų sintezės inhibitorių poveikį paprastosios drebulės (Populus tremula L.) eksplantų vystymuisi in vitro. Palyginus su auksinų ir citokininų klasių fitohormonais, kurie plačiai pritaikomi medžių mikrovegetatyviniam dauginimui, giberelinų poveikis sumedėjusiems augalams in vitro kultūroje yra ištirtas gana mažai. Tokie tyrimai svarbūs dėl jų praktinio pritaikymo galimybės, kadangi vis didėja vegetatyviškai padaugintų medžių, ypač plantacinei miškininkystei tinkamų drebulių, poreikis. / The aim of this research work was to investigate the effect of gibberellins and gibberellin biosynthesis inhibitors on common aspen (Populus tremula L.) explants. In comparison to phytohormones of auxin and cytokinin classes that are widely applied for the micropropagation of trees, the effect of gibberellins on woody plants in in vitro culture is not so well known. The investigation of this effect seems to be important because of the possibility of practical application, inasmuch as the need for vegetatively multiplied trees, especially for aspens suitable for plantation forestry, is constantly increasing.
55

The potential of aspen clones and hybrids for enhanced forest management in Alberta

Gylander, Timothy Unknown Date
No description available.
56

Genetic adaptation of aspen populations to spring risk environments: a novel remote sensing approach

Li, Haitao Unknown Date
No description available.
57

Avian use, nest-site selection, and nesting success in Sierra Nevada aspen

Richardson, Thomas Willoughby. January 2007 (has links)
Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "August 2007." Includes bibliographical references. Online version available on the World Wide Web.
58

Modeling the cumulative effects of aspen management practices on timber and wildlife at multiple spatial and temporal scales

Felix, Alexandra B. January 2008 (has links)
Thesis (Ph.D.)--Michigan State University. Dept. of Fisheries and Wildlife, 2008. / Title from PDF t.p. (viewed on Apr. 3, 2009) Includes bibliographical references (p. 330-340). Also issued in print.
59

Biotic communities of the aspen parkland of central Canada

Bird, Ralph Durham, January 1900 (has links)
Published also as Thesis (Ph. D.)--University of Illinois, 1929. / Cover title. "Contribution from the Zoological laboratory of the University of Illinois no. 365." Reprinted from Ecology, vol. XI, no. 2, April, 1930. "Literature cited": p. 426-431.
60

20th Century forest-grassland ecotone shift and effects of livestock herbivory

Sankey, Temuulen Tsagaan. January 2005 (has links) (PDF)
Thesis (Ph. D)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: Cliff Montagne. Includes bibliographical references.

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