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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.
71

Bark cloth : Swedish consumer attitudes towards sustainable fabrics

Nakirulu, Esther January 2013 (has links)
The fashion industry is faced with a challenge of the world’s population today and it is therefore looking for other alternatives of dressing up the entire population since cotton is at its extinction. This study introduces an African crafted sustainable textile fabric called Bark cloth. The research includes the details of the fabric, the production process and what the fabric can be used for in order to give the reader a deeper understanding of the fabric and why it is interesting to be added on the Swedish market. A qualitative methodology is used and that is to say; interviews have been conducted as well as empirical data review which is used as basis on both primary and secondary data hence this helped in providing valid information for this study. The study findings and results are greatly based on the field study the author made recently in Uganda to broaden this project and the study is also be based on the information was be gathered from the other empirical sources such as interviews and the literature. The study scope outcomes will be applicable to the fashion council that that is seeking help in finding out how cotton can be substituted and it will also be very useful at the Swedish School of Textiles and the Textile museum in Boras.
72

Population ecology of the beech scale (Cryptococcus fagisuga Ldgr.)

Gate, Imogen Mary January 1990 (has links)
No description available.
73

Bark Beetle-Induced Changes to Crown Fuel Flammability and Crown Fire Potential

Page, Wesley G 01 May 2014 (has links)
Recent outbreaks of mountain pine beetle (Dendroctonus ponderosae Hopkins) in lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests and spruce beetle (Dendroctonus rufipennis Kirby) in Engelmann spruce (Picea engelmannii Parry ex Engelm.) forests have affected vast areas across western North America. The highlevels of tree mortality associated with these outbreaks have raised concerns amongst fire managers and wildland firefighters about the effects of the tree mortality on fire behavior, particularly crown fire behavior, as crown fires hinder the ability of firefighters to conduct safe and effective fire suppression operations. Current information regarding crown fire dynamics in recently attacked forests is limited to results obtained from simulations employing either inappropriate and/or unvalidated fire behavior models based on inadequate descriptions of crown fuel flammability. The purpose of this research was to measure and characterize the changes in crown fuel flammability caused y recent bark beetle attack and to describe the implications of these changes on crown fire potential in affected forests. Results indicated that bark beetle attack causes a significant decline in moisture content and change in chemical composition in lodgepole pine and Engelmann spruce tree foliage, which substantially increases foliage flammability. Additionally, it was found that conventional models used to predict the moisture content of fine, dead surface fuels were inappropriate for predicting the moisture content of foliage on mountain pine beetle-attacked lodgepole pine trees during the red stage. Therefore, calibrated operational models and models based on diffusion theory were developed and evaluated that could accurately predict hourly fluctuations in moisture content. The implications of these changes on crown fire potential are dependent upon a host of site specific factors including outbreak duration, severity, and the specific stand characteristics. Based on our results, we believe that current fire behavior models, including popular semi-empirical and physics-based models, are currently inadequate for accurately predicting crown fire potential in forests recently attacked by bark beetles. In order to make significant progress in our understanding of crown fire potential in recently attacked forests, a substantial effort to document wildfire behavior in the field and/or to conduct experimental fires is needed.
74

Accelerated Composting of Hardwood Bark Amended with Organic and Inorganic Fertilizer

Bakhshizadeh, Hoda 15 December 2012 (has links)
The objectives of this study were: 1) To evaluate short-term composting of hardwood bark with combinations of poultry litter and ammonium nitrate and 2) To determine the suitability of composted material for ornamental plant media. In a 3-month accelerated composting study, hardwood bark was amended with (20% & 40%) poultry litter, (1% & 2%) ammonium nitrate, or unamended. Composting was run in fifteen 35- gallon containers and samples were collected at day 0, 45, and 90 for pH, moisture content, carbon-to-nitrogen ratio, compost maturity, toxicity, and green house evaluations. The amendment containing 40% poultry litter showed significantly higher weight reduction than others at days 45 and 90. Also, this treatment showed significantly higher mass weight in transplanted zinnia and gardenia than other treatments and was comparable to commercial media. Overall, results indicated that the amendment of hardwood bark with poultry litter could produce comparable product to currently used commercial container media.
75

Bionomics of two aspen bark beetles : Trypophloeus populi and Procryphalus mucronatus (coleoptera:scolytidae)

Petty, Jerold L. 21 July 1976 (has links)
Beetles of Trypophloeus populi attacked green bark of unhealthy aspen (Populus tremuloides) and hastened the death of the tree. Beetles of Procryphalus mucronatus favored dead bark and were of little significance in the death of the aspen. These two beetle species were distinguished from each other by their primary galleries, eggs, larvae, larval mines, and mating behavior. In T. populi, there were three larval instars and one to one and one-half generations per year; only larvae overwintered, and the eggs of the first generation were present by mid-July. In P. mucronatus, there were two larval instars and one and one-half to two generations per year; both larvae and adults overwintered, and the first eggs of the new season were present by late May.
76

Seasonal effects of first commercial thinning on Ips activity in north Mississippi loblolly pine stands

Floyd, James Daniel 17 August 2013 (has links)
In comparison to the southern pine beetle (SPB), (Dendroctonus frontalis Zimmermann), less is known about the three species of Ips bark beetles; the six-spined engraver, Ips calligraphus (Germar); the eastern five-spined engraver, Ips grandicollis (Eichhoff); and the small southern pine engraver, Ips avulses (Eichhoff). Ips commonly enter a stand following the first commercial thinning, feeding on slash and stressed individuals. However, the factors that influence Ips severity are poorly understood. Therefore, this project was designed to study the seasonal effects of first commercial thinning operations on Ips activity in north Mississippi loblolly pine stands. Treatments represented the most commonly used thinning practices in this area (i.e., a fifth row harvest with select, a third row harvest with select, and control). Treatments were duplicated three times per site and two sites were utilized to compare Ips movement to harvesting season.
77

Studies of natural products from Liriodendron tulipifera, Simmondsia californica and hardwood bark compost.

Wilton, John Howard January 1982 (has links)
No description available.
78

Evaluation of a bark adsobent for removal of pharmaceuticals from wastewater

Krona, Johanna January 2017 (has links)
During and after medical treatment, pharmaceutical compounds as well as their metabolites and conjugates are excreted from the users through urine and feces. The pharmaceuticals end up in wastewater treatment plants, which are not designed to deal with this kind of organic micro-pollutant. Eventually the pharmaceuticals end up in the environment where they can have adverse physiological and behavioral effects on aquatic life and could contribute to the spread of antibiotic resistance among microorganisms. Adsorption to activated carbon is an established method for removal of pharmaceuticals from wastewater. It is however quite expensive and it is of interest to identify cost-effective alternatives. One possible alternative is bark, which is a common by-product from forest industry and has a complex microstructure and high porosity compared to many other naturally occurring materials. In order to investigate the potential of using bark to remove pharmaceuticals from municipal wastewater four column filters were built, two with activated carbon and two with bark. They were used in an experiment conducted at Kungsängsverket, the largest wastewater treatment plant in Uppsala municipality. The objectives were to assess pharmaceutical concentrations in treated wastewater at Kungsängsverket and to compare the performance of bark and activated carbon filters under different loading rates. During this time the filters were run at different loading rates and two different types of bark was used. 24 common pharmaceuticals from different therapeutic groups were targeted. The pharmaceutical concentrations measured at Kungsängsverket were generally low, but mean concentrations of five pharmaceuticals (atenolol, metoprolol, furosemide, hydrochlorothizide and diclofenac) exceeded 250 ng/l. Out of these, four have been shown to have adverse effects on aquatic life and it would be preferable if they were not released into the recipient. Bark was not as good at removing pharmaceuticals from wastewater as activated carbon was, but decent removal rates were achieved for several compounds. The removal rates of either filter type did not seem to be significantly impacted by variations in loading rate or bark size. The concentrations of a few compounds increased after treatment with the bark filters and the reason for this is not clear. One possibility is interference from other organic substances in the wastewater or the bark, but determining the reason for this increase should be a priority for any further research on the subject. Another problem encountered during the project that is likely to pose a problem for future implementation is that the bark filters were very sensitive to clogging. Running the filters at full scale would require frequent back-washing which would be a disadvantage from both economical and practical reasons.
79

Análise das concentrações energéticas no limiar entre fonemas vozeados e não-vozeados e suas implicações para fins de reconhecimento de locutores dependente do discurso / Analysis of energy cocentrations in the threshold between voiced and unvoiced phonemes and their implications for text-dependent speaker recognition

Ishizawa, William Habaro 19 February 2015 (has links)
Atualmente, diversos trabalhos e aplicações são desenvolvidos com foco na área de reconhecimento computacional de locutores. À medida que o interesse por diversas aplicações reais dentro dessa área emerge, principalmente em biometria, na qual a segurança e a eficácia são de extrema importância, torna-se cada vez mais necessário que estudos sejam feitos, na mesma proporção, visando avaliá-las. Desse modo, a proposta do presente trabalho é a de mensurar a acurácia de um sistema de reconhecimento de locutores baseado em características elementares, isto é, energias de sub-bandas de frequências, em associação com um classificador probabilístico, estudando a viabilidade de extraí-las das transições entre trechos vozeados e não-vozeados (TTVNV) dos sinais. Testes são realizados com diferentes quantidades de locutores e discurso fixado. A acurácia obtida nos testes variam de 20.18% a 92.53%. Os resultados obtidos são comparados e relatados, complementando as afirmações existentes na literatura sobre o uso das TTVNV com dados quantitativos. / Nowadays, many works and applications are developed focusing on computational speaker recognition. As the interest for several real applications within this area emerges, especially in biometrics, where the safety and the efficacy of the applications are extremely important, studies need to be developed in the same proportion, to evaluate the effectiveness of such approaches. Based on that, this work intends to measure the accuracy of a speaker recognition system that uses elementar features, i.e., sub-band frequency energies, associated with a probabilistic classifier, studying the viability of extracting them from the transition between voiced and unvoiced speech tags (TTVNV). Tests are carried out with different numbers of speakers and a text-dependent approach. The accuracy of the tests varies from 20.18% to 92.53%. The results are compared and reported, complementing the existent information on the use of TTVNV with quantitative data.
80

Hot water-soluble glycosides location in the tissue of Populus grandidentata bark /

Erickson, Richard L. January 1969 (has links) (PDF)
Thesis (Ph. D.)--Institute of Paper Chemistry, 1969. / Includes bibliographical references (p. 97-99).

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