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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.
31

Assessing Available Woody Plant Biomass on Rangelands with Lidar and Multispectral Remote Sensing

Ku, Nian-Wei 2011 May 1900 (has links)
The majority of biofuels are produced from corn and grain. The drawback to these sources of biofuels is the vast amount of cultivated land needed to produce substantial amounts of biofuel, potentially increasing the price of food and livestock products. Mesquite trees, a type of woody plant, are a proven source of bioenergy feedstock found on semi-arid lands. The overall objectives of this study were to develop algorithms for determining woody plant biomass on rangelands in Texas at plot-level using terrestrial lidar and at the local scale by integrating reference biomass and multispectral imagery. Terrestrial lidar offers a more efficient method for estimating biomass than traditional field measurements. Variables from the terrestrial lidar point cloud were compared to ground measurements of biomass to find a best fitting regression model. Two processing methods were investigated for analyzing the lidar point cloud data, namely: 1) percentile height statistics and 2) a height bin approach. Regression models were developed for variables obtained through each processing technique for estimating woody plant, above-ground biomass. Regression models were able to explain 81 percent and 77 percent of the variance associated with the aboveground biomass using percentile height statistics and height bins, respectively. The aboveground biomass map was generated by using the cokriging interpolation method with NDVI and ground biomass data. According to cross-validation, ordinary cokriging estimated biomass accurately (R^2 = 0.99). The results of this study revealed that terrestrial lidar can be used to accurately and efficiently estimate the aboveground biomass of mesquite trees in a semi-arid environment at plot level. Moreover, spatial interpolation techniques proved useful in scaling up biomass estimates to local scale.
32

Patterns of savanna formation in former semiarid grasslands the interactive role of climate change, soil texture and neighbor identity /

Resco de Dios, Víctor. January 2008 (has links)
Thesis (Ph.D.)--University of Wyoming, 2008. / Title from PDF title page (viewed on Mar. 9, 2010). Includes bibliographical references.
33

Grass production changes with mesquite (Prosopis juliflora) reinvasion in southern Arizona

Williams, Patrick Thomas, 1942- January 1976 (has links)
No description available.
34

Application of paper chromatography to the determination of the molecular constitution of mesquite gum

Anderson, Frank Wallace, 1921- January 1952 (has links)
No description available.
35

An ecological survey of a mesquite bosque

Gavin, Thomas A. (Thomas Alan) January 1973 (has links)
No description available.
36

Ecology of riparian breeding birds along the Colorado River in Grand Canyon, Arizona

Brown, Bryan T. January 1987 (has links)
Thesis (Ph. D. - Renewable Natural Resources)--University of Arizona, 1987. / Includes bibliographical references (leaves 62-66).
37

Symbiotic effects on the fungus Glomus Sp. on chromium(III), chromium(VI), and lead(II) uptake by mesquite (Prosopis Sp.) a novel method to remediate heavy metals /

Arias, Jack A. January 2009 (has links)
Thesis (Ph. D.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
38

Utilização da algaroba (Prosopis juliflora) como plataforma para a obtenção de bionanocompósito / Use of mesquite (Prosopis juliflora) as platform for obtaining bionanocompósito

Nascimento, Rafael Morais do January 2014 (has links)
NASCIMENTO, Rafael Morais do. Utilização da algaroba (Prosopis juliflora) como plataforma para a obtenção de bionanocompósito. 2014. 69 f. Dissertação (Mestrado em química)- Universidade Federal do Ceará, Fortaleza-CE, 2014. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-10-11T17:05:40Z No. of bitstreams: 1 2014_dis_rmnascimento.pdf: 1877509 bytes, checksum: 246d8377fc031f6f2edb06d4d2ce488a (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-10-11T23:51:34Z (GMT) No. of bitstreams: 1 2014_dis_rmnascimento.pdf: 1877509 bytes, checksum: 246d8377fc031f6f2edb06d4d2ce488a (MD5) / Made available in DSpace on 2016-10-11T23:51:34Z (GMT). No. of bitstreams: 1 2014_dis_rmnascimento.pdf: 1877509 bytes, checksum: 246d8377fc031f6f2edb06d4d2ce488a (MD5) Previous issue date: 2014 / This work seeks to develop a bionanocompósito drawn from galactomannan and crystals nanocelulose, both obtained from Prosopis juliflora. Initially, carob pods were subjected to grinding, milling, heating, filtration and centrifugation in order to yield a viscous solution which, with the addition of ethanol, the precipitate was possible galactomannan. So all fractions, and galactomannan fiber capsules were separated. The gum obtained was lyophilized and characterized, as its composition, as well as the fibrous fractions. Further, the fibers of the capsules underwent the hydrothermal process mesquite, followed by a bleaching with H2O2 and NaOH solutions) and acidic hydrolysis (H2SO4 60% v / v) for extracting nanocelulose. After hydrolysis one estávl suspension nanocelulose characterized by TGA, XRD, FTIR and zeta potential was obtained. Then galactomannan films were prepared, starting from a 5% (w / v) polysaccharide solution using glycerol as plasticizer. Movies, nanocelulose were added at concentrations of 3, 5 and 7%, and evaluated the influence of the addition of the nanocrystals in the mechanical, thermal and barrier properties to water vapor. The galactomannan extracted from mesquite presented, respectively, in protein, lipid, ash and moisture content of 5.3%, 2.3%, 4.0% and 5.2% and characteristic thermal behavior, showing exothermic event to 284.7 ° C, typical of his degradation. Their functional groups identified by FTIR, and determination of its mass and molar ratio mannose / galactose. The fiber showed considerable differences in their levels of cellulose, hemicellulose, lignin, insoluble lignin, extractives, ash and moisture, after treatments. These results were corroborated by analysis of FTIR, XRD and TGA. And through the characterizations of the films, it was proved that there were improvements in the thermal, mechanical and barrier properties, the obtained biocomposites, with the addition of nanocelulose. / Este trabalho busca o desenvolvimento de um bionanocompósito elaborado a partir de galactomanana e cristais de nanocelulose, ambos obtidos da algaroba (Prosopis juliflora). Inicialmente, vagens da algaroba foram submetidas à trituração, moagem, aquecimento, filtração e centrifugação obtendo-se uma solução viscosa onde, com a adição de etanol, foi possível precipitar a galactomanana. Então as frações de interesse, galactomanana e fibra das cápsulas, foram separadas. A goma obtida foi liofilizada e caracterizada, quanto a sua composição, assim como as frações fibrosas. Na sequência, as fibras das cápsulas da algaroba sofreram processo hidrotérmico, seguido de dois branqueamentos com soluções de NaOH e H2O2, e hidrólise ácida (H2SO4 60% v/v) para extração de nanocelulose. Após a hidrólise, foi obtida uma suspensão estável de nanocelulose, caracterizada por TGA, DRX, potencial zeta e FTIR. Então foram preparados filmes de galactomanana, a partir de uma solução 5% (m/v) do polissacarídeo, utilizando glicerol como plastificante. Aos filmes, foram adicionados nanocelulose, nas concentrações de 3, 5 e 7%, e avaliado a influência da adição dos nanocristais nas propriedades mecânicas, térmicas e de barreira a vapor de água. A galactomanana extraída da algaroba apresentou, respectivamente, teores de proteína, lipídio, cinzas e umidade de 5,3%, 2,3%, 4,0% e 5,2% e comportamento térmico característico, apresentando evento exotérmico a 284,7°C, típico de sua degradação. Seus grupos funcionais identificados por FTIR, além da determinação de sua massa molar e razão manose/galactose. A fibra apresentou consideráveis diferenças nos seus teores de celulose, hemicelulose, lignina solúvel, lignina insolúvel, extrativos, cinzas e umidade, após os tratamentos. Esses resultados foram corroborados por análises de FTIR, DRX e TGA. Através das caracterizações dos filmes, ficou comprovado que a adição de nanocelulose melhorou propriedades térmicas, mecânicas e de barreira, dos biocompósitos obtidos.
39

Use of mesquite (Prosopis juliflora) as platform for obtaining bionanocompÃsito / UtilizaÃÃo da algaroba (Prosopis juliflora) como plataforma para a obtenÃÃo de bionanocompÃsito

Rafael Morais do Nascimento 26 February 2014 (has links)
This work seeks to develop a bionanocompÃsito drawn from galactomannan and crystals nanocelulose, both obtained from Prosopis juliflora. Initially, carob pods were subjected to grinding, milling, heating, filtration and centrifugation in order to yield a viscous solution which, with the addition of ethanol, the precipitate was possible galactomannan. So all fractions, and galactomannan fiber capsules were separated. The gum obtained was lyophilized and characterized, as its composition, as well as the fibrous fractions. Further, the fibers of the capsules underwent the hydrothermal process mesquite, followed by a bleaching with H2O2 and NaOH solutions) and acidic hydrolysis (H2SO4 60% v / v) for extracting nanocelulose. After hydrolysis one estÃvl suspension nanocelulose characterized by TGA, XRD, FTIR and zeta potential was obtained. Then galactomannan films were prepared, starting from a 5% (w / v) polysaccharide solution using glycerol as plasticizer. Movies, nanocelulose were added at concentrations of 3, 5 and 7%, and evaluated the influence of the addition of the nanocrystals in the mechanical, thermal and barrier properties to water vapor. The galactomannan extracted from mesquite presented, respectively, in protein, lipid, ash and moisture content of 5.3%, 2.3%, 4.0% and 5.2% and characteristic thermal behavior, showing exothermic event to 284.7  C, typical of his degradation. Their functional groups identified by FTIR, and determination of its mass and molar ratio mannose / galactose. The fiber showed considerable differences in their levels of cellulose, hemicellulose, lignin, insoluble lignin, extractives, ash and moisture, after treatments. These results were corroborated by analysis of FTIR, XRD and TGA. And through the characterizations of the films, it was proved that there were improvements in the thermal, mechanical and barrier properties, the obtained biocomposites, with the addition of nanocelulose. / Este trabalho busca o desenvolvimento de um bionanocompÃsito elaborado a partir de galactomanana e cristais de nanocelulose, ambos obtidos da algaroba (Prosopis juliflora). Inicialmente, vagens da algaroba foram submetidas à trituraÃÃo, moagem, aquecimento, filtraÃÃo e centrifugaÃÃo obtendo-se uma soluÃÃo viscosa onde, com a adiÃÃo de etanol, foi possÃvel precipitar a galactomanana. EntÃo as fraÃÃes de interesse, galactomanana e fibra das cÃpsulas, foram separadas. A goma obtida foi liofilizada e caracterizada, quanto a sua composiÃÃo, assim como as fraÃÃes fibrosas. Na sequÃncia, as fibras das cÃpsulas da algaroba sofreram processo hidrotÃrmico, seguido de dois branqueamentos com soluÃÃes de NaOH e H2O2, e hidrÃlise Ãcida (H2SO4 60% v/v) para extraÃÃo de nanocelulose. ApÃs a hidrÃlise, foi obtida uma suspensÃo estÃvel de nanocelulose, caracterizada por TGA, DRX, potencial zeta e FTIR. EntÃo foram preparados filmes de galactomanana, a partir de uma soluÃÃo 5% (m/v) do polissacarÃdeo, utilizando glicerol como plastificante. Aos filmes, foram adicionados nanocelulose, nas concentraÃÃes de 3, 5 e 7%, e avaliado a influÃncia da adiÃÃo dos nanocristais nas propriedades mecÃnicas, tÃrmicas e de barreira a vapor de Ãgua. A galactomanana extraÃda da algaroba apresentou, respectivamente, teores de proteÃna, lipÃdio, cinzas e umidade de 5,3%, 2,3%, 4,0% e 5,2% e comportamento tÃrmico caracterÃstico, apresentando evento exotÃrmico a 284,7ÂC, tÃpico de sua degradaÃÃo. Seus grupos funcionais identificados por FTIR, alÃm da determinaÃÃo de sua massa molar e razÃo manose/galactose. A fibra apresentou considerÃveis diferenÃas nos seus teores de celulose, hemicelulose, lignina solÃvel, lignina insolÃvel, extrativos, cinzas e umidade, apÃs os tratamentos. Esses resultados foram corroborados por anÃlises de FTIR, DRX e TGA. AtravÃs das caracterizaÃÃes dos filmes, ficou comprovado que a adiÃÃo de nanocelulose melhorou propriedades tÃrmicas, mecÃnicas e de barreira, dos biocompÃsitos obtidos.
40

Delineating the current and potential distributions of prosopis glandulosa in the square kilometre array South Africa, Karoo site

Buthelezi, Nomcebo Siphesihle January 2019 (has links)
A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Geographical Information Systems and Remote Sensing, 2019 / Prosopis species (also known as Mesquite), in particular P. glandulosa (Honey Mesquite) have a negative impact on indigenous biodiversity and the livelihood of communities in the semi-arid and arid parts of South Africa. The spread of these species is a threat to the environments in which they have been introduced as they spread at high rates, increase the mortality of indigenous trees and disrupt important ecosystem processes such as hydrological and nutrient cycles. Due to the negative impacts of Prosopis on important ecosystem services and South Africa’s native biodiversity, it is essential for the distribution of these species to be identified, controlled and monitored in order to mitigate their spread and restore damaged ecosystems. The objectives of this study were to use Remote Sensing and Geographic Information Systems (GIS) tools to: (i) delineate the distribution of Prosopis using high resolution satellite imagery, (ii) determine the changes in spatial distribution of these species in the period 2003-2017, and (iii) use moderate spatial resolution satellite imagery and ancillary environmental data to predict areas susceptible to future invasion.. The study area used in this investigation is the Square Kilometre Array (SKA SA) site, situated in Northern Cape Province, South Africa. Satellite images were classified using Multi-layer Perceptron (MLP) Neural Network classification algorithm to improve the land use land cover classification accuracy. A WordView-3 image with 1.24 m spatial resolution was used to delineate the distribution of Prosopis in the study area for the year 2016. Landsat images from the years 2003, 2008, 2013 and 2017 were used to conduct a change detection analysis. The prediction model developed in the study was able to predict Prosopis cover for the years 2017 and 2022 cover using ancillary environmental data and land use land cover maps. The study was also able to quantify the area covered by Prosopis species for the years 2017 and 2022. / XN2020

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