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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.
11

Atividade repelente e carrapaticida de extratos e óleos essenciais de plantas sobre o carrapato bovino Rhipicephalus microplus / Repellent and carrageenan activity of extracts and essential oils of plants on the bovine tick Rhipicephalus microplus

Lima, Aldilene da Silva 26 February 2014 (has links)
Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-06-22T19:03:02Z No. of bitstreams: 1 AldileneSilvaLima.pdf: 13164666 bytes, checksum: cd1c6e1b366f76a72539ecddec6062e4 (MD5) / Made available in DSpace on 2017-06-22T19:03:02Z (GMT). No. of bitstreams: 1 AldileneSilvaLima.pdf: 13164666 bytes, checksum: cd1c6e1b366f76a72539ecddec6062e4 (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Rhipicephalus microplus is an ectoparasite of major economic importance to cattle. The control cattle tick has difficult by resistance of populations to synthetic acaricides. Plant bioactive molecules can be an alternative to control this ectoparasite. The aim of this study was to evaluate the repellent and acaricide effect of extracts and essential oils from plants on the cattle tick R. microplus. Hexane, ethyl ether, ethanolic, and methanolic extracts was obtained of P. tuberculatum fruits. After extraction, all of the extracts were dried. Essential oil from L. alba was obtained by hydrodistillation, all oil essential of Citrus ssp. were extracted by cold pressing fruits and all the identification of the major compounds of essential oils was performed by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography flame ionization detector (GC-FID). Monoterpenes was obtained commercially. All the extracts was use larval packet tests and Adult immersion tests. Oil essential was used to repellency test. All extracts showed highest larvicidal activity against R. microplus. Hexane extract showed a CL50 of 0.04 mg/mL, CL50 ethyl ether of 0.08 mg/mL and ethanolic LC50 of 2.73 mg/mL. P. tuberculatum fruit extracts were also effective against engorged females R. microplus. Genotypes LA-13 and LA-57 of L. alba showed repellent activity against larvae of R. microplus more than 40 hours at concentration of 6.88 mg/cm². Monoterpenes showed lower repellent activity. Oil essenctial of Citrus aurantium var. dulcis showed repellent activity more than 30 hours at concentration of 6.88 mg/cm². Other essential oils tested showed a time of repellency lower 5 hours. Ours results reported than plants contains bioactive compounds with great potential acaricides, and they can be commercial products for the control of R. microplus. / O Rhipicephalus microplus é um ectoparasita de maior importância econômica à bovinocultura. O controle do carrapato bovino tem sido dificultado pela resistência de populações aos acaricidas sintéticos. Compostos bioativos de plantas podem ser uma alternativa para o controle deste ectoparasita. O objetivo deste trabalho foi avaliar o efeito repelente e carrapaticida de extratos e óleos essenciais de plantas sobre o carrapato bovino R. microplus. Extratos da planta Piper tuberculatum foram obtidos com hexano, éter etílico, etanólico e metanólico. Depois todos os extratos foram rotoevaporado. Os óleos essenciais de Lippia alba foram obtidos por hidrodestilação, os de Citrus ssp. por prensagem a frio dos frutos e todos os componentes dos óleos essenciais foram analisados por Cromatografia Gasosa acoplada a espectrometria de massa (CG-MS). Os monoterpenos utilizados foram obtidos comercialmente. Todos os extratos foram utilizados no teste de larvas e imersão de fêmeas Ingurgitadas. Os óleos essenciais foram utilizados no teste de repelência. Todos os extratos demonstraram uma alta atividade sobre larvas de R. microplus. O extrato Hexânico de frutos de P. tuberculatum apresentou uma CL50 de 0,04 mg/mL, seguido de éter etílico com CL50 de 0,08 mg/mL, etanólico com CL50 de 2,73 mg/mL. O extrato éter etílico de frutos de P. tuberculatum também demonstrou uma alta atividade sobre fêmeas Ingurgitadas. Os genótipos LA-13 e LA-57 de Lippia alba apresentaram uma alta atividade repelente sobre larvas de R. microplus por mais de 40 horas numa concentração de 6,88 mg/cm². Os monoterpenos apresentaram baixa atividade repelente. O óleo essencial de Citrus aurantium var. dulcis apresentou uma alta atividade repelente com mais de 30 horas de repelência na concentração de 6,88mg/cm². Os demais óleos testados apresentaram um tempo de repelência menor que 5 horas. Nossos resultados demonstraram que as plantas possuem compostos ativos com alto potencial acaricida, e que podem vir a serem utilizados em produtos de uso comercial para o controle do carrapato bovino.
12

Remediation of Soil Hydrophobicity on a Coastal USGA Sand-Based Golf Green

Thompson, Troy David 01 June 2010 (has links)
Managing soil hydrophobicity caused by localized dry spots (LDS) on sand based golf greens has become one of the greatest challenges for golf course superintendents and managers, especially as water restrictions intensify. The purpose of this study was to evaluate the effectiveness of thirteen soil surfactants in eliminating LDS and in maximizing root zone soil moisture on a sand based USGA golf green located on the California Central Coast. Potential water repellency of air dried cores (measured utilizing the water droplet penetration time (WDPT) method), phytotoxicity, and climate were analyzed during two experimental trials. Phytotoxicity data was collected for Trial I using visual quality ratings and for Trial II using a chlorophyll meter. Phytotoxicity decreased during Trial I. Differences in phytotoxicity as measured using chlorophyll index were not at all significant during Trial II (p = 1). Ten of the thirteen wetting agent treatments significantly (p < 0.001) decreased soil hydrophobicity compared with the other wetting agent treated plots and the non-treated control. More frequent application of Cascade Plus resulted in a more significant reduction in soil hydrophobicity. Increasing the application rates also resulted in the reduction of soil hydrophobicity. Wetting agent treatment 6-CP(10day) maintained the highest volumetric water content (VWC) but treatment 13-2079337 maintained the highest levels for wetting agents treated monthly.
13

Repelling Contarinia Nasturtii (diptera: Cecidomyiidae), A Brassica Specialist, Using Non-Host Essential Oils

Stratton, Chase 01 January 2019 (has links)
Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), is an invasive pest causing marketable losses on Brassica crops in the Northeastern United States and throughout southern Canada. Heading brassicas, like cauliflower and broccoli, are particularly susceptible because larvae feed concealed inside meristematic tissues of the plant, where head formation occurs. Our work details the development of a sustainable, affordable pest management tactic for swede midge – plant derived repellents. First, it was necessary to establish both a damage and marketability threshold for swede midge, so we developed a technique to manipulate larval density of swede midge on cauliflower, We asked: (1) What is the swede midge damage threshold? (2) How many swede midge larvae can render cauliflower crowns unmarketable? and (3) Does the age of cauliflower at infestation influence the severity of damage? We found that even a single larva causes mild twisting and scarring rendering cauliflower unmarketable 52% of the time, with more larvae causing more severe damage and additional losses, regardless of cauliflower age at infestation. Repellency is an important management approach to consider for swede midge. Since the host range of specialist insects appears constrained by plant phylogeny, we hypothesized that odors from less phylogenetically related plants would be more repellent to swede midge. To test our hypothesis, we performed no-choice and choice biological assays, asking: (1) How do essential oils from different plant species influence midge densities on broccoli? (2) What is the relationship between phylogenetic distance of non-host odors and larval densities on broccoli? Biological assays identified multiple essential oils that reduced larval densities, and phylogenetic analyses showed that less related plants were more effective. In addition to the biological assays, we tested 15 essential oils for their ability to repel gravid females from broccoli tissue in y-tube olfactometer assays. While most of the essential oils reduced the frequency at which females chose host plant meristems, wintergreen, thyme, lemongrass, eucalyptus lemon, garlic, cinnamon, and star anise were most effective. Additionally, we used chemical fingerprints (physical/chemical properties) from PubChem to compare the essential oil volatile compounds and develop an index for their similarity. We found that physicochemical similarity was predictive of repellency. Finally, for repellency to be an effective, long-term strategy, it was important to consider how and whether the repellent response of midges changes over time or previous experience. In our final chapter, we performed electroantennography trials testing how previous experience with garlic or eucalyptus lemon odor for one or 10 s influences the neurophysiological response of swede midge to host (broccoli) or non-host (garlic or eucalyptus lemon) odors. We asked: (1) Does previous experience with garlic or eucalyptus lemon influence the physiological response of swede midge to host or non-host odors? (2) Does the time of previous exposure to non-host odors influence their physiological response to host or non-host odors? Our findings show that swede midge, after 10 s of exposure to either repellent, was more responsive to repellents than host compounds, suggesting that the effectiveness of repellents will not diminish over time.
14

Use of soil moisture dynamics and patterns at different spatio-temporal scales for the investigation of subsurface flow processes

Blume, Theresa, Zehe, Erwin, Bronstert, Axel January 2009 (has links)
Spatial patterns as well as temporal dynamics of soil moisture have a major influence on runoff generation. The investigation of these dynamics and patterns can thus yield valuable information on hydrological processes, especially in data scarce or previously ungauged catchments. The combination of spatially scarce but temporally high resolution soil moisture profiles with episodic and thus temporally scarce moisture profiles at additional locations provides information on spatial as well as temporal patterns of soil moisture at the hillslope transect scale. This approach is better suited to difficult terrain (dense forest, steep slopes) than geophysical techniques and at the same time less cost-intensive than a high resolution grid of continuously measuring sensors. Rainfall simulation experiments with dye tracers while continuously monitoring soil moisture response allows for visualization of flow processes in the unsaturated zone at these locations. Data was analyzed at different spacio-temporal scales using various graphical methods, such as space-time colour maps (for the event and plot scale) and binary indicator maps (for the long-term and hillslope scale). Annual dynamics of soil moisture and decimeterscale variability were also investigated. The proposed approach proved to be successful in the investigation of flow processes in the unsaturated zone and showed the importance of preferential flow in the Malalcahuello Catchment, a datascarce catchment in the Andes of Southern Chile. Fast response times of stream flow indicate that preferential flow observed at the plot scale might also be of importance at the hillslope or catchment scale. Flow patterns were highly variable in space but persistent in time. The most likely explanation for preferential flow in this catchment is a combination of hydrophobicity, small scale heterogeneity in rainfall due to redistribution in the canopy and strong gradients in unsaturated conductivities leading to self-reinforcing flow paths.
15

THE EFFECT OF SOIL WATER REPELLENCY AND FUNGAL HYDROPHOBICITY ON SOIL WATER DYNAMICS IN THE ATHABASCA OIL SANDS

2014 March 1900 (has links)
Surface mining of the Athabasca Oil Sands of Canada is occurring at an unparalleled rate resulting in large scale disturbances over vast areas. Soil water availability for plants is one of the key issues faced when reclaiming the landscape. A factor which limits the soil water availability is soil water repellency (SWR). Soil water repellency is found on both natural and disturbed sites in this region and can cause reduced infiltration, reduced soil water storage, enhanced runoff, increased preferential flow, and reduced ecosystem productivity. Effective characterization of SWR, determination of the causes of SWR and understanding how it affects soil pores and water flow are important for environmental management. The main objective of this study is to examine the effect of SWR and fungal hydrophobicity on soil water dynamics in Athabasca Oil Sands. This was accomplished by determining the relationship between the measurement of severity and persistence of SWR and the critical water content (CWC) where SWR is greatest between different soils in the region. Examining how the water conducting porosity and soil pores are affected by SWR. Developing methods to quantify fungal strains that cause SWR and testing of these fungal strains for their ability to alter the SWR and infiltration into soil. Results show that a high severity (Contact angle) of repellency does not necessarily denote long persistence (Water Drop Penetration Time) or high CWC in soils from the region. A high severity of SWR in larger diameter pores decreased the water conducting porosity due to the larger pore contribution to the total liquid flux. The modified microscopy approach and the alcohol percentage test (APT) resulted in improved characterization of fungal hydrophobicity. Fungal strains were classified as hydrophilic, hydrophobic and chrono-amphililic based on their surface properties from these measurements. The surface property of selected fungi strains can alter the SWR in both a repellent and wettable soil and can also change the water infiltration rate. This research highlights the importance of characterization of SWR, the effects on water flow, and how fungal hydrophobicity can alter the SWR and infiltration. This will aid in improving our understanding of SWR and improve remediation efforts on water repellent soils in the Athabasca Oil Sands region.
16

Betulin-modified cellulosic textile fibers with improved water repellency, hydrophobicity and antibacterial properties

Huang, Tianxiao January 2019 (has links)
Textiles made from natural sources, such as cotton and flax, have advantages over those made of synthetic fibers in terms of sustainability. Unlike major synthetic fibers that have a negative impact on the environment due to poor biodegradability, cotton cellulose is a renewable material.Cotton cellulose fibers exhibit various attractive characteristics such as softness and inexpensiveness. Cellulosic textiles can be easily wetted, since the structure contains a large amount of hydrophilic hydroxyl groups, and when water repellency is needed, this is a disadvantage. Currently, paraffin waxes or fluorinated silanes are used to achieve hydrophobicity, but this contradicts the concept of green chemistry since these chemicals are not biodegradable. The use of bio-based materials like forest residues or side-streams from forest product industries might be a good alternative, since this not only decreases the pressure on the environment but can also increase the value of these renewable resources.Betulin is a hydrophobic extractive present in the outer bark of birch trees (Betula verrucosa). Nowadays, the birch bark containing betulin generated in the paper industry is disposed of by incineration as a solid fuel to provide energy, but this application is not highly valuable and this motivates us to see whether betulin can be used as a hydrophobe to prepare waterproof cellulosic textiles. Methods of dip-coating, film compression molding and grafting were performed to build “betulin-cellulosic textile system” to render the textile with hydrophobicity and other functions. The textile impregnated in a solution of betulin-based copolymer exhibited a contact angle of 151°, which indicated that superhydrophobicity can be reached. AATCC water spray test results showed that cellulosic textile coated with betulin-based film had a water repellency of 80, which is the third highest class according to the rating standards. Betulin-grafted textiles were also prepared and showed a static water contact angle of 136°, and an antibacterial property with a bacterial removal of 99%.This thesis proposes that betulin can be used as a green alternative in functional material preparation. By developing betulin, a more value-added application rather than incineration can be achieved. / <p>QC 20190205</p>
17

Post-fire Interactions Between Soil Water Repellency, Islands of Fertility, and Bromus tectorum Invasibility

Fernelius, Kaitlynn Jane 18 December 2013 (has links) (PDF)
An intrinsic link exists between soil moisture and soil nitrogen. Factors that increase or decrease soil moisture can have a profound effect on soil nitrogen cycling, which may have later repercussions in the plant community. Post-fire soil water repellency is one factor that can limit soil moisture acquisition and may indirectly affect nitrogen cycling and weed invasion in woody islands of fertility. Plots centered on burned Juniperus osteosperma trees were either left untreated or treated with a surfactant to ameliorate water repellency. Two years later, soils were excavated from the untreated and treated field plots. In the greenhouse, half of each soil type received a surfactant treatment while the other half was left untreated. Pots were seeded with either Bromus tectorum or Pseudoroegneria spicata. Analysis of field soil prior to the greenhouse trial showed that untreated, repellent soils had inorganic nitrogen levels an order of magnitude higher than wettable, surfactant-treated soils. Greenhouse pots that had received a surfactant treatment in the field and/or greenhouse had similar soil water content, plant density, and above ground biomass, which were, respectively, 55-101%, 31 to 34 -fold, and 16 to 18 -fold greater than pots without a surfactant treatment. No species effects were found. This study indicates that water repellency can reduce wetting and retention of water in the soil while promoting the retention of high levels of inorganic nitrogen. However, the effects of soil water repellency on inorganic nitrogen appeared to have a minimal effect on plant growth compared to the effect of soil water repellency on water availability.
18

Influence of Soil Water Repellency on Post-fire Revegetation Success and Management Techniques to Improve Establishment of Desired Species

Madsen, Matthew D. 17 December 2009 (has links) (PDF)
The influence of soil water repellency (WR) on vegetation recovery after a fire is poorly understood. This dissertation presents strategies to broaden opportunities for enhanced post-fire rangeland restoration and monitoring of burned piñon and juniper (P-J) woodlands by: 1) mapping the extent and severity of critical and subcritical WR, 2) determining the influence of WR on soil ecohydrologic properties and revegetation success, and 3) evaluating the suitability of a wetting agent composed of alkylpolyglycoside-ethylene oxide/propylene oxide block copolymers as a post-fire restoration tool for ameliorating the effects of soil WR and increasing seedling establishment. Results indicate that: • Post-fire patterns of soil WR were highly correlated to pre-fire P-J woodland canopy structure. Critical soil WR levels occurred under burned tree canopies while sub-critical WR extended out to approximately two times the canopy radius. At sites where critical soil WR was present, infiltration rate, soil moisture, and vegetation cover were significantly less than at non-hydrophobic sites. These parameters were also reduced in soils with subcritical WR relative to non-hydrophobic soils (albeit to a lesser extent). Aerial photography coupled with feature extraction software and geographic information systems (GIS) proved to be an effective tool for mapping P-J cover and density, and for scaling-up field surveys of soil WR to the fire boundary scale. • Soil WR impairs seed germination and seedling establishment by decreasing soil moisture availability by reducing infiltration, decreasing soil moisture storage capacity, and disconnecting soil surface layers from underlying moisture reserves. Consequently, soil WR appears to be acting as a temporal ecological threshold by impairing establishment of desired species within the first few years after a fire. • Wetting agents can significantly improve ecohydrologic properties required for plant growth by overcoming soil WR; thus, increasing the amount and duration of available water for seed germination and seedling establishment. Success of this technology appears to be the result of the wetting agent increasing soil moisture amount and availability by 1) improving soil infiltration and water holding capacity; and 2) allowing seedling roots to connect to underling soil moisture reserves.
19

Alternatives to Conventional Fluorocarbon based Soil Resistant Treatment for Automotive Interior Textiles : An Evaluative Study

Baghaei, Behnaz, Mehmood, Faisal January 2011 (has links)
During the last two decades, the applications of fluorocarbon based chemicals to provide soil resistant or soil release properties for automotive interior and upholstery have increased tremendously. But, recent studies showed that the soil resistant treatment based on fluorochemicals has detrimental effects on the environment as well as on humans due to the presence of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) content. PFOS and PFOA are toxic, bio accumulative and bio persistent fluoro-organic compounds. This project focus on PFOS and PFOA-free soil resistant chemicals and their application on interior textiles used for automotive. Literature study was done by keeping in mind all the aspects regarding soil and nature of soils, soil resistant mechanism, PFOA and PFOS-free soil resistant chemicals, chemistry of the chemicals, area of the application and the method of application. Experimental application of PFOA and PFOS-free soil resistant chemicals by using different concentrations on 100% Polyester dyed and unfinished fabric was performed with Pad-Dry-Cure method. Experimental application was carried out to evaluate the soil resistant treated samples for soil resistant, clean ability and colour change results. At the end, the comparison of the results of three mentioned evaluations gave us the best possible alternatives. / Program: Magisterutbildning i textilteknologi
20

Latossolo húmico sob diferentes usos no agreste meridional de Pernambuco : atributos químicos, físico-hidricos e biológicos

BEZERRA, Cidney Barbosa 25 August 2016 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-22T13:08:59Z No. of bitstreams: 1 Cidney Barbosa Bezerra.pdf: 2167272 bytes, checksum: 5f0cef27593c95187e77811cdb520cbb (MD5) / Made available in DSpace on 2017-02-22T13:08:59Z (GMT). No. of bitstreams: 1 Cidney Barbosa Bezerra.pdf: 2167272 bytes, checksum: 5f0cef27593c95187e77811cdb520cbb (MD5) Previous issue date: 2016-08-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The South Agreste Pernambucano has an agricultural and very large land diversification, but the management of the soil used in the production is mostly inadequate, resulting in economic and low productivity losses, allied to it have weather conditions quite different typical of a transitional environment . However the city of Brejão has a special condition with cooler and rainy weather and deeper soils and well structured, with occurrence horizon latosols with the humic something characteristic in this swamp of altitude. So the aim of this study was to investigate the changes in chemical, physical and water attributes of the surface horizon humic an Oxisol subjected to different forms of management in the Swamp region of South Agreste Altitude Pernambuco, and investigate the soil repellency water. The disturbed and undisturbed soil samples were collected in a native forest (MN), pasture 5 years (PA5) and grazing 30 (PA30) in three layers 0 to 10 cm, 10 to 20 cm and 20 to 30 cm and evaluated the chemical, biological, physical and water attributes, as was also done an infiltration test with simple ring. Chemical attributes presented typicality dystrophic yellow latosols, and attributes related to the acidity showing significant results mainly in the surface layer. For biological attributes your changes are more significant in macroaggregates. Have the physical attributes that most change with inadequate management are the bulk density (Ds) and porosity consequently these physical attributes are linked to water retention in the soil and all water dynamics. For the infiltration test it is clear the presence of soil water repellency. / O Agreste Meridional pernambucano possui uma diversificação agropecuária e de solos muito grande, porém o manejo do solo empregado na produção é em sua maioria inadequado, acarretando em perdas econômicas e baixa produtividade, aliadas a isso temos condições climáticas bastante diferentes típicas de um ambiente de transição. No entanto a cidade de Brejão possui uma condição especial, com clima mais frio e chuvoso e solos mais profundos e bem estruturado, com ocorrência de latossolos de horizonte com A húmico algo característico nesse brejo de altitude. Assim o objetivo deste trabalho foi investigar as alterações nos atributos químicos, físicos e hídricos do horizonte superficial A húmico de um Latossolo Amarelo submetido a diferentes formas de manejo na região do Brejo de Altitude do Agreste Meridional pernambucano, e investigar a repelência do solo a água. As amostras deformadas e indeformadas do solo foram coletadas em uma área de mata nativa (MN), pasto de 5 anos (PA5) e pasto de 30 anos (PA30), em três camadas 0 a 10 cm, 10 a 20 cm e 20 a 30 cm e foram avaliados os atributos químicos, biológicos, físicos e hídricos, como também foi realizado um teste de infiltração com anel simples. Os atributos químicos apresentaram tipicidade de latossolos amarelo distróficos, e atributos relacionados com a acidez apresentando resultados significativos principalmente na camada superficial. Para os atributos biológicos suas alterações são mais expressivas nos macroagregados. Já os atributos físicos que mais sofreram alterações com o manejo inadequado são a densidade do solo (Ds) e a porosidade, consequentemente esses atributos físicos estão ligados a retenção de água no solo e toda dinâmica hídrica. Pelo teste de infiltração fica claro a presença de repelência do solo a água.

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