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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.
331

Diversidade taxonômica, filogenética e funcional de aves em gradientes ambientais na caatinga

Correia, Kelly Isadora de Oliveira 27 July 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Biological diversity is a broad, deep and multifaceted concept that describes all variability of living forms on different spatial and temporal scales and levels of organization. Even among species, diversity can assume distinct characters, including a taxonomic, a phylogenetic and a functional one. Semiarid ecosystems such as the Caatinga were poorly addressed from an integrated perspective of its biodiversity. The region possess high biotic variability and undergoes intense pressures from abiotic and anthropogenic factors. With around 500 species known in the biome, birds compose an expressive biological group in the Caatinga, with distinct evolutionary lineages and ecological features. This study aims to understand the evolutionary and ecological aspects of the diversity of birds of the Caatinga and their environmental drivers. Specifically, we aim to (i) summarize the existing knowledge on birds assemblages in the biome, their phylogenetic relationships and ecological (i.e., functional) differences; (ii) investigate the interrelationships among taxonomic, phylogenetic and functional diversity, including their distinct measures; (iii) evaluate the effects of different environmental (climatic and structural) gradients on these different dimensions of bird diversity; and (iv) evaluate the effects of these factors on the functional diversity based on individual traits. We gathered information of 123 birds assemblages from the Caatinga based on the available literature, and used a species-level phylogenetic tree and a set of speciesspecific functional traits to estimate the phylogenetic and functional diversities, respectively. Also, we explored different diversity metrics, aiming to understand their interrelationships and select those less biased by species richness and sampling effort. 523 species composed the regional diversity of the Caatinga. The phylogenetic and functional diversity patterns were coincident regarding spatial distribution and environmental hypothesis, with current climate as the leading factor. Nonetheless, the diversity of individual traits diverged qualitatively and quantitatively from the total functional diversity. These results reinforce the need to intensify the sampling efforts in the Caatinga, allow us to comprehend the effects of environmental conditions on birds assembling in ecological and evolutionary terms and, finally, warns to the problem of selecting ecological traits to describe functional diversity. / Diversidade biológica é um conceito amplo, profundo e multifacetado que descreve toda variabilidade de formas de vida em diferentes escalas espaciais, temporais e níveis de organização. Mesmo entre espécies, a diversidade pode assumir distintos caráteres, incluindo o taxonômico, o evolutivo e funcional. Ecossistemas semiáridos como a Caatinga foram pouco estudados sob uma perspectiva integrada da biodiversidade. A região possui alta variabilidade biótica e sofre intensa pressão de fatores abióticos e antrópicos. Com cerca de 500 espécies conhecidas no bioma, as aves compõem um grupo biológico expressivo da Caatinga, com distintas linhagens evolutivas e características ecológicas. Este trabalho objetiva compreender os aspectos evolutivos e ecológicos da diversidade de aves da Caatinga e seus determinantes ambientais. Especificamente, buscamos (i) sumarizar o conhecimento existente sobre as assembleias de aves do bioma, suas relações filogenéticas e diferenças ecológicas (funcionais); (ii) investigar as inter-relações entre a diversidade taxonômica, filogenética e funcional, incluindo distintas medidas destas; (iii) avaliar os efeitos de diferentes gradientes ambientais (climáticos e estruturais) sobre essas diferentes dimensões da diversidade; e (iv) avaliar os efeitos desses fatores sobre a diversidade funcional de traços individuais. Reunimos informações de 123 assembleias de aves da Caatinga a partir da literatura disponível e utilizamos uma árvore filogenética das espécies e um conjunto de traços funcionais espécie-específicos para estimar a diversidade filogenética e funcional, respectivamente. Ainda, exploramos diferentes métricas de diversidade, a fim de entender suas inter-relações e selecionar aquelas menos enviesadas pela riqueza e esforço amostral. 523 espécies compuseram a diversidade regional da Caatinga. Os padrões de diversidade filogenética e funcional foram coincidentes quanto à distribuição espacial e a hipótese ambiental, tendo o clima atual como fator principal. Entretanto, a diversidade de traços funcionais individuais divergiu qualitativa e quantitativamente da diversidade funcional total. Esses resultados reforçam a necessidade de intensificar os esforços amostrais na Caatinga, permitem compreender o efeito das condições ambientais na formação das assembleias de aves em termos ecológicos e evolutivos, e por fim, alerta para o problema de selecionar traços ecológicos para descrever a diversidade funcional.
332

Descritor de movimento baseado em tensor e histograma de gradientes

Perez, Eder de Almeida 24 August 2012 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-03-06T15:14:46Z No. of bitstreams: 1 ederdealmeidaperez.pdf: 749381 bytes, checksum: 7338f694cc850057100e730b520d74eb (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-03-06T20:25:35Z (GMT) No. of bitstreams: 1 ederdealmeidaperez.pdf: 749381 bytes, checksum: 7338f694cc850057100e730b520d74eb (MD5) / Made available in DSpace on 2017-03-06T20:25:35Z (GMT). No. of bitstreams: 1 ederdealmeidaperez.pdf: 749381 bytes, checksum: 7338f694cc850057100e730b520d74eb (MD5) Previous issue date: 2012-08-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O reconhecimento de padrões de movimentos tem se tornado um campo de pesquisa muito atrativo nos últimos anos devido, entre outros fatores, à grande massificação de dados em vídeos e a tendência na criação de interfaces homem-máquina que utilizam expressões faciais e corporais. Esse campo pode ser considerado um dos requisitos chave para análise e entendimento de vídeos. Neste trabalho é proposto um descritor de movimentos baseado em tensores de 2a ordem e histogramas de gradientes (HOG - Histogram of Oriented Gradients). O cálculo do descritor é rápido, simples e eficaz. Além disso, nenhum aprendizado prévio é necessário sendo que a adição de novas classes de movimentos ou novos vídeos não necessita de mudanças ou que se recalculem os descritores já existentes. Cada quadro do vídeo é particionado e em cada partição calcula-se o histograma de gradientes no espaço e no tempo. A partir daí calcula-se o tensor do quadro e o descritor final é formado por uma série de tensores de cada quadro. O descritor criado é avaliado classificando-se as bases de vídeos KTH e Hollywood2, utilizadas na literatura atual, com um classificador Máquina Vetor Suporte (SVM). Os resultados obtidos na base KTH são próximos aos descritores do estado da arte que utilizam informação local do vídeo. Os resultados obtidos na base Hollywood2 não superam o estado da arte, mas são próximos o suficiente para concluirmos que o método proposto é eficaz. Apesar de a literatura apresentar descritores que possuem resultados superiores na classificação, suas abordagens são complexas e de alto custo computacional. / The motion pattern recognition has become a very attractive research field in recent years due to the large amount of video data and the creation of human-machine interfaces that use facial and body expressions. This field can be considered one of the key requirements for analysis and understanding in video. This thesis proposes a motion descriptor based on second order tensor and histograms of oriented gradients. The calculation of the descriptor is fast, simple and effective. Furthermore, no prior knowledge of data basis is required and the addition of new classes of motion and videos do not need to recalculate the existing descriptors. The frame of a video is divided into a grid and the histogram of oriented gradients is computed in each cell. After that, the frame tensor is computed and the final descriptor is built by a series of frame tensors. The descriptor is evaluated in both KTH and Hollywood2 data basis, used in the current literature, with a Support Vector Machine classifier (SVM). The results obtained on the basis KTH are very close to the descriptors of the state-of-the-art that use local information of the video. The results obtained on the basis Hollywood2 not outweigh the state-of-the-art but are close enough to conclude that the proposed method is effective. Although the literature presents descriptors that have superior results, their approaches are complex and with computational cost.
333

Minigradientes isolate e Optiprep como alternativas ao gradiente de Percoll na produção in vitro de embriões bovinos / Isolate and Optiprep minigradients as alternatives to Percoll gradient in bovine in vitro embryo production

VIANNA, Liziane Lemos 28 February 2011 (has links)
Made available in DSpace on 2014-08-20T14:38:01Z (GMT). No. of bitstreams: 1 dissertacao_liziane_vianna.pdf: 321138 bytes, checksum: e8e76002b27c6cb6d710d3cd63a4c088 (MD5) Previous issue date: 2011-02-28 / The objective of this study was to evaluate alternative methods to the gradient of Percoll® for sperm selection used in bovine in vitro production systems. We evaluated the following parameters: sperm quality, embryo development, the viability after cryopreservation and sex ratio of bovine embryos produced in vitro. Four treatments were performed: percoll group (90 and 45%) 4 mL, centrifuged at 700xg for 20 min; minipercoll group (90 and 45%) 800 &#956;L, centrifuged at 700xg for 5 min; miniisolate group (90 and 45%) 800 &#956;L, centrifuged at 700xg for 5 min; and minioptiprep group (30,28 and 26%) 1,2 mL, centrifuged at 900xg for 15 min. Different gradients did not affect the semen characteristics compared with the evaluation immediately after thawing (P>0,05). It was only observed a decrease in total motility in minioptiprep group (P<0,05). The cleavage rates were similar among the percoll and miniisolate groups (P>0,05). Minipercoll and minioptiprep groups were lower to percoll (P<0,05) and similar to isolate (P>0,05). At Day 7 the developmental rates were higher in miniisolate group than other groups (P<0,05). But at D8 the developmental rates of minigradients were similar to percoll (P>0,05). Among the minigradientes, the miniisolate was higher to minipercoll and minioptiprep (P<0,05). The treatments did not affect the sex ratio expected of 50:50% (P.0,05) and there was no difference among the four groups (P>0,05). Also, there was no difference in survival rates after vitrification (P>0,05). In conclusion, the miniisolate and the minioptiprep groups, in the concentration and volume used in our experiment, reached similar results to the percoll group. So, they are alternatives to the gradient of Percoll® in the routine of IVP bovine embryos. / O objetivo do presente estudo foi avaliar possíveis alternativas ao gradiente de Percoll®, para seleção espermática, no sistema de produção in vitro de embriões bovinos. Foram avaliados os seguintes parâmetros: qualidade espermática, desenvolvimento embrionário, viabilidade após a criopreservação e a proporção sexual dos embriões bovinos produzidos in vitro. Foram realizados quatro tratamentos: grupo percoll (90 e 45%) - 4 mL, centrifugado 700xg por 20 min; grupo minipercoll (90 e 45%) 800 &#956;L, centrifugado a 700xg por 5 min; gupo miniisolate (90 e 45%) 800 &#956;L, centrifugado a 700xg por 5 min; e grupo minioptiprep (30, 28 e 26%) - 1,2 mL, centrifugado a 900xg por 15 min. A passagem pelos gradientes não afetou as características do sêmen em comparação com a avaliação realizada logo após o descongelamento (P>0,05), sendo somente observada uma diminuição da motilidade total para o grupo minioptiprep (P<0,05). Quanto a produção in vitro de embriões, não foi observada diferença na taxa de clivagem entre os grupos percoll e miniisolate (P>0,05), sendo o minipercoll e o minioptiprep inferiores ao percoll (P<0,05) e semelhantes ao miniisolate (P>0,05). No desenvolvimento embrionário, o miniisolate foi superior aos demais grupos em D7 (P<0,05). Em D8, os três minigradientes foram semelhantes ao percoll (P>0,05). Entre os minigradientes, o miniisolate foi superior ao minipercoll e ao minioptiprep (P<0,05). A passagem pelos gradientes não afetou a proporção sexual esperada de 50:50%, além disso, não houve diferença entre os grupos (P>0,05). Não houve diferença quanto à taxa de sobrevivência a vitrificação nos quatro grupos em 48 h (P>0,05). Concluímos que o miniisolate e o minioptiprep, nas concentrações e volumes estudados neste trabalho, atingiram resultados semelhantes ao percoll. Portanto, são alternativas a utilização do gradiente de Percoll®, na rotina de produção de embriões bovinos in vitro.
334

Eco-Hydrology of a Seasonally Dry Tropical Forest : Tree Growth, Belowground Water Dynamics and Drought-Vulnerability

Tarak, Rutuja Chitra January 2016 (has links) (PDF)
Tropical forests are storehouses of more thanhalf of the world‘s biodiversity and play a key role in global carbon, water and energy cycles. However, as a consequence of rapid anthropogenic climate change, biodiversity and climate functions of these forests are under a threat. Climate is changing not only in mean state but its variability is increasing, with extreme events such as droughts, heat waves and storms also rising. Water is fundamental to plants‘ existence, and in the tropics, is a key determinant of plant species‘richness, composition, growth and survival. There is thus an increasing interest in understanding how changing rainfall may cause functional changes in forests or change their species composition. Therefore, the overarching goal of thisdissertation was to understand the impact of water variability on tropical forest tree growth and vulnerability to drought.Forest tree growth along spatial and temporal rainfall gradientsObservational studies that measure whole forest tree growth along spatial or temporal gradients of rainfall are the most common way of formulating forest growth response curves to water availability, when manipulative experiments are cost-prohibitive or impractical (fire or large mammal disturbance). In the tropics, since very few species show anatomically distinct tree rings, estimating tree growth from trunk diameter is the standard practice to obtain growth patterns across species. However, this method—of equating woody growth to diameter change--is susceptible to bias from water-induced stem flexing. In the absence of bias correction, temporal variability in growth is likely to be overestimated and incorrectly attributed to fluctuations in resource availability, especially in forests with high seasonal and inter-annual variability in water. This problem has been largely ignored in the absence of any corrective measure and due to under-appreciation of the magnitude of error. While diameter re-censuses in permanent sampling plots (PSPs) have been most commonly done at 3-5 year scale (using a graduate tape), increasingly they are done at seasonal and annual scales (using band dendrometers) to closely match variation in rainfall, the scales at which hydrostatic bias may be greater in magnitude relative to woody growth. Besides, along a spatial rainfall gradient, inter-annual variability in water may vary, causing systematic differences in the hydrostatic bias for forests along the gradient. Therefore, one broad objective of this thesis was to evaluate the problem of hydrostatic bias in whole forest growth-rainfall relationship at annual and supra-annual scales, for temporal as well as spatial rainfall gradients and propose and test a novel corrective solution.Further, it also examines if growth-diameter relationship vary along the spatial gradient, which it may arise due to differences in light environments and/or disturbance history and species composition. The missing link of Eco-hydrology Differential responses of tree species in terms of growth and survival to variation in water that they can access, the proximate cause is likely shaped through their life-history strategies, the ultimate cause. However, we neither know the depths at which the diverse tree species in a forest draw water from and its dynamics, nor variation in water at those depths vis-à-vis rainfall patterns—for lack of appropriate methods. This has been a key missing link in understanding how water shapes trees‘ life-history strategies, their demographic trade-offs and co-existence, and also our predictive ability to determine species-specific responses to changing rainfall patterns, especially droughts. Since droughts are highly stochastic events and trees‘ responses to their drought ―experiences‖ may be revealed at decadal scales, long-term evaluations are key. Therefore, the second broad objective of this thesis was to develop a framework to determine trees’ water uptake depths, variation in water availability at those depths and trees’ demographic responses over multiple decades. From this, to understand how belowground hydrology shapes drought-vulnerability, demographic trade-offs and coexistence of forest tree species. This thesis titled—Eco-Hydrology of a Seasonally Dry Tropical Forest: Tree Growth, Belowground Water Dynamics and Drought-Vulnerability—is organized as follows: Chapter 1 lays down an introduction to the thesis, followed by a description of the study site and datasets used in the thesis in Chapter 2. This thesis uses a variety of methods and multiple datasets, all of which are from the protected Seasonally Dry Tropical Forests of the Western Ghats in southern India in the Mudumalai and Bandipur National Parks. It is then followed by three data chapters: Chapter 3 describes the seasonal fluctuations in a five year long (1980-1985) tree diameter time series (using dendrometers) of a Seasonally Dry Tropical Forest in Bandipur National Park to illustrate the issue of hydrostatic stem-flexing. It investigates the possibility that band dendrometers may themselves underestimate stem shrinkage at diurnal or seasonal scale. It also evaluates if there could be a best season and time of the day for undertaking forest diameter censuses that can minimize hydrostatic bias. Chapter 4(published in Forest Ecology and Management)measures the hydrostatic bias in a sample of trees in a 50 ha PSP of a Seasonally Dry Tropical Forest in Mudumalai National Park, and proposes a novel way to correct this bias at the whole community level in the 20 year long 4-year interval growth time series. Chapter 5 (in review with Environmental Research Letters) investigates and presents two new confounding factors in growth-rainfall relationships along a spatial rainfall gradient: hydrostatic bias and size-dependency in growth rates. For this it evaluates forest tree growth estimates in seven 1-ha PSPs (~800 trees, 3-year annual time series 9using dendrometers) along a 1000 mm rainfall gradient spanning a mesic savanna-moist forest transition in Mudumalai National Park. Using the period for which seasonal diameter time series was available (2 yrs), it evaluates if the extent of seasonal fluctuations systematically vary along the gradient—most likely due to hydrostatic stem flexing. It also describes the presence of an anomalous size-diameter relationship in the mesic savanna from a large plots (50 ha PSP, diameter records using graduated tape). These observations are then used to draw insights for ―space for time‖ substitution modeling. Chapter 6 (in prep for Nature Plants) analyses belowground water environments of trees over two decades (1992-2012), a period that includes a prolonged and intense drought, in the 50 ha PSP of a Seasonally Dry Tropical Forest in Mudumalai. It uses a locally parametarised dynamic hydrological model in which site rainfall is also a forcing variable. It then develops a novel dynamic growth model and inversely estimates water uptake depths for adult trees of all common species (include ~9000 trees) in the PSP from their above-ground growth patterns over two decades vis-à-vis belowground water availability at multiple depths. It then examines if species‘ water uptake depth obtained thus is a predictor of their drought-driven mortality. Finally, this is used to evaluate the hydrological niche partitioning tree species operate under and how that drives their water uptake strategies, demographic trade-offs, and drought-vulnerability. Summarizes the thesis and suggests future directions
335

Influência da matéria orgânica extraída do material particulado em suspensão na disponibilidade de metais potencialmente tóxicos na laguna Mundaú, Alagoas / Influence of organic matter extracted by suspension particulated in the availibility of toxic potencially metals in the Mundaú lagoon, Alagoas

Silva, Erismarck Ananias da 17 August 2017 (has links)
The Mundaú lagoon is part of the main estuary complex of Alagoas, called Mundaú-Manguaba, contributing directly to the socioeconomic development of the cities of Maceió, Coqueiro Seco and Santa Luzia do Norte through tourism, fishing and agriculture. However, the disordered occupation in its surroundings, lack of basic sanitation, effluent releases and the entry of pesticides from intensive agricultural activity cause problems of environmental contamination. In this work, it was verified how the contamination altered the physical-chemical parameters pH, conductivity, hardness, NO3-, PO43-, SO42-, NH4+, total organic carbon (TOC) and the Cu, Fe, Mn , Ca, Mg, Pb, Zn, Ni, Cd and Cr total metal concentration. It was also evaluated how the natural organic matter contained in the suspended particulate material (NOM-SPM) extracted from the lagoon influences the availability of the Cd2+ and Pb2+ metal cations, using the chronopotenciometric electrochemical technique of Absence Gradients and Nernstian Equilibrium Stripping (AGNES). The physical-chemical parameters were measured from 9 points collected in the lagoon and compared with the resolution 357/2005 CONAMA for brackish water, with pH and conductivity measured in situ; hardness by complexometry with EDTA; chloride ions by the Mohr method; the PO43-, SO42-, NO3-, NH4+ ions determined by spectrophotometry, the PO43- by the molybdenum blue method, SO42- by the turbidimetric method with BaCl2, NH4+ by the indophenol blue method and NO3- by the Gries reaction. TOC was measured by catalytic combustion with infrared detection and the total metal concentration performed by atomic absorption spectrometry. NOM-SPM was obtained by extracting the suspended particulate material from the samples, filtering them in a 0,45 μm pore membrane, and then extracting the NOM-SPM using 0,1 mol L-1 NaOH as an extractor, MON-MPS was characterized by UV-Vis spectroscopy, molecular fluorescence and TOC, to obtain the degree of humification and aromaticity. Then, titration tests of the Cd2+ and Pb2+ metals were carried out with the MON-MPS 0,45 mg L-1 TOC, and the values of the complexation capacity (CC) and the conditional stability constant (K ') at pH 5 and 6. The results of the physical-chemical characterization showed that the lagoon has values of PO43-, NO3-, TOC, Fe, Zn and Pb above that allowed by Brazilian legislation for this type of ecosystem. The concentration of total Pb, in particular, reached 1,32 mg L-1, the maximum value allowed by resolution 357/2005 CONAAM is 0,210 mg L-1. The degree of humification of NOM-SPM indicated more aromatic functional groups than aliphatic structures, suggesting that it may be a good natural complexing agent for metals. The K 'and CC values show that NOM-SPM has more affinity for Pb2+ cations than for Cd2+, being in agreement with other NOM matrices described in the literature. It is concluded that there is a need for actions to remediation and minimize the indiscriminate disposal of contaminants in the lagoon so that the physicochemical parameters are adequate to the legislation and that NOM-SPM of the lagoon Mundaú acts as a good natural regulator for Pb2+ and Cd2+, being more effective for the first one, helping to reduce their availability to the biota in the form of free cations. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A laguna Mundaú faz parte do principal complexo estuarino de Alagoas, denominado Mundaú-Manguaba, contribuindo, diretamente, para o desenvolvimento socioeconômico das cidades de Maceió, Coqueiro Seco e Santa Luzia do Norte por meio do turismo, da pesca e da agropecuária. No entanto, a ocupação desordenada em seu entorno, falta de saneamento básico, lançamentos de efluentes e a entrada de agrotóxicos oriundos da atividade agropecuária intensiva causam problemas de contaminação ambiental. Verificou-se, neste trabalho, como essa contaminação alterou os parâmetros físico-químicos pH, condutividade, dureza, NO3-, PO43-, SO42-, NH4+, carbono orgânico total (COT) e a concentração total dos metais Cu, Fe, Mn, Ca, Mg, Pb, Zn, Ni, Cd e Cr. Avaliou-se, também, como a matéria orgânica natural contida no material particulado em suspensão (MON-MPS) extraído da própria laguna influencia na disponibilidade dos cátions metálicos Cd2+ e Pb2+, utilizando-se da técnica eletroquímica cronopotenciométrica de redissolução no equilíbrio nernstiano e na ausência de gradientes (AGNES). Os parâmetros físico-químicos foram medidos a partir de 9 pontos coletados na laguna e comparados com a resolução 357/2005 CONAMA para água salobras, sendo o pH e condutividade medidos in situ; a dureza por complexometria com EDTA; os íons cloreto pelo método de Mohr; os íons PO43-, SO42--, NO3-, NH4+ determinados por espectrofotometria, sendo o PO43- pelo método do azul de molibdênio, SO42- pelo método turbidimétrico com BaCl2, NH4+ pelo método do azul de indofenol e NO3- pela reação de Gries. O COT foi medido por combustão catalítica com detecção de infravermelho e a concentração de metal total realizada por espectrometria de absorção atômica. A obtenção da MON-MPS se deu pela extração do material particulado em suspensão das amostras, filtrando-as em membrana de 0,45 μm de poro, para em seguida extrair a MON-MPS utilizando NaOH 0,1 mol L-1 como extrator. Caracterizou-se a MON-MPS por espectroscopia de UV-Vis, fluorescência molecular e COT, para obter o grau de humificação e aromaticidade. Em seguida, fez-se ensaios de titulação dos metais Cd2+ e Pb2+ com a MON-MPS 0,45 mg L-1 COT, medindo-se por meio da AGNES os valores da capacidade de complexação (CC) e da constante de estabilidade condicional (K’) nos pH 5 e 6. Os resultados da caracterização físico-química mostraram que a laguna está com valores de PO43-, NO3-, COT, Fe, Zn e Pb acima do permitido pela legislação brasileira para este tipo de ecossistema. A concentração de Pb total, em especial, alcançou o valor de 1,32 mg L-1, sendo que o valor máximo permitido pela resolução 357/2005 CONAAM é 0,210 mg L-1. O grau de humificação da MON-MPS indicou mais grupos funcionais aromáticos do que estruturas alifáticas, sugerindo que ela é pode ser um bom agente complexante natural para metais. Os valores de K’ e de CC mostram que a MON-MPS tem mais afinidade pelos cátions Pb2+ do que pelos Cd2+, estando de acordo com outras matrizes de MON descritas na literatura. Conclui-se que há necessidade de ações de remediação e minimização do descarte indiscriminado de contaminantes na laguna para que os parâmetros físico-químicos se adequem à legislação e, que a MON-MPS da laguna Mundaú atua como um bom regulador natural para Pb2+ e Cd2+, sendo mais efetivo para o primeiro, ajudando a diminuir a disponibilidade dos mesmos para a biota na forma de cátions livres.
336

Advanced numerical techniques for the acoustic modelling of materials and noise control devices in the exhaust system of internal combustion engines

Sánchez Orgaz, Eva María 16 May 2016 (has links)
[EN] This Thesis is focused on the development and implementation of efficient numerical methods for the acoustic modelling and design of noise control devices in the exhaust system of combustion engines. Special attention is paid to automotive perforated dissipative silencers, in which significant differences are likely to appear in their acoustic behaviour, depending on the temperature variations within the absorbent material. Also, material heterogeneities can alter the silencer attenuation performance. Therefore, numerical techniques considering all these features are required to guarantee the accuracy of the results. A literature review is carried out, mainly related to one-dimensional models, as well as to acoustic models for absorbent materials and perforated surfaces. However, plane wave model limitations make indispensable using alternative multidimensional methods. In addition, the possibility of using new acoustic elements is explored. These elements have as an objective being a potential alternative to the fibrous absorbent materials, which can have a negative impact on health. The Thesis considers the use of microperforated and sintered surfaces. The latter have, in some cases, a nearly constant acoustic impedance, whose value depends, among others, on the thickness and porosity of the plates. To avoid the limitations of plane wave models, a finite element (FE) approach is proposed for the acoustic analysis of dissipative silencers including a perforated duct with uniform axial mean flow and an outer chamber with a heterogeneous distribution of the absorbent material. On the other hand, property variations can be also produced by temperature gradients. In this case, a hybrid FE model has been derived for perforated dissipative silencers including: (1) Thermal gradients in the central duct and the chamber; (2) A perforated passage carrying non-uniform axial mean flow. A FE approach has been implemented to solve the pressure-based wave equation for a non-moving heterogeneous medium, associated with the chamber. Also, the governing equation in the central duct has been written and solved in terms of an acoustic velocity potential to allow the presence of an axially inhomogeneous flow. The coupling between both regions has been carried out by means of a perforated duct and its acoustic impedance, adapted here to include absorbent material heterogeneities and mean flow effects. It has been found that the presence of non-homogeneities can have a significant influence on the acoustic attenuation of a silencer and should be included in the theoretical models. Optimization techniques for industrial noise control devices are relevant, since they lead to the production of elements with better characteristics. Evolutionary algorithms are emergent techniques able to obtain a solution, even in those problems in which the traditional optimization have difficulties. Optimization techniques are combined with the FE method to achieve the maximum attenuation in the frequency range of interest. A multichamber silencer optimization problem is defined and several analyses are carried out to obtain the most suitable configuration for each application. Under certain assumptions of axial uniformity, several techniques have been considered to reduce the computational effort of a full 3D FE analysis for dissipative silencers with temperature gradients and mean flow. These are based on a decomposition of the acoustic field into transversal and axial modes within each silencer subdomain, and a matching procedure of the modal expansions at the silencer area changes through the continuity conditions of the acoustic fields. The relative computational efficiency and accuracy of predictions for the matching techniques are studied, including point collocation at nodes and Gauss points and also mode-matching with weighted integration. All of them provide accurate predictions of the attenuation and improve the computational cost of a FE calculation / [ES] Esta Tesis se centra en el desarrollo e implementación de métodos numéricos eficientes para el diseño y modelado de componentes de la línea de escape en motores de combustión interna. Merecen especial atención los silenciadores disipativos perforados de automóviles, ya que su comportamiento acústico puede sufrir variaciones importantes debidas a las variaciones de temperatura en el material absorbente, así como a las heterogeneidades de la fibra. Por tanto, se requieren técnicas numéricas que consideren estos casos para garantizar la precisión de los resultados. Se lleva a cabo una revisión bibliográfica que recoge los modelos de onda unidimensionales, así como modelos acústicos de materiales absorbentes y superficies perforadas. Sin embargo, las limitaciones de los primeros hacen indispensable el uso de modelos multidimensionales. Además se explora la posibilidad de usar nuevos elementos acústicos, cuyo objetivo es ser una alternativa potencial a los materiales absorbentes, que pueden tener un efecto negativo sobre la salud. La Tesis considera el uso de superficies microperforadas y sinterizadas. Estas últimas en algunos casos presentan una impedancia casi constante, cuyo valor depende, entre otras cosas, del espesor y la porosidad de las placas. Para evitar las limitaciones de los modelos de onda plana, se propone un enfoque en elementos finitos (EF) para el análisis acústico de silenciadores disipativos que incluyen un conducto con flujo medio axial uniforme y una cámara externa con una distribución heterogénea de material absorbente. Por otro lado, la variación de las propiedades también puede producirse por gradientes térmicos. En este caso, se propone una formulación híbrida de EF para silenciadores disipativos perforados que incluye: (1) Gradientes térmicos en el conducto central y la cámara; (2) Un conducto perforado que canaliza flujo medio axial no uniforme. Se ha implementado una formulación de EF para resolver la ecuación de ondas en términos de presión para el medio estacionario heterogéneo asociado a la cámara. Además, la ecuación asociada al conducto central, expresada en términos de potencial de velocidad acústica, permite la presencia de flujo axial no uniforme. El acoplamiento entre ambas regiones se ha realizado mediante un conducto perforado y su impedancia acústica y se ha adaptado para incluir la citada falta de homogeneidad. Se ha visto que las heterogeneidades pueden influir notablemente en la atenuación acústica de un silenciador, debiéndose incluir en los modelos teóricos. Las técnicas de optimización para componentes industriales de control de ruido son importantes, ya que producen elementos con mejores características. Los algoritmos evolutivos son técnicas emergentes capaces de obtener una solución, incluso cuando la optimización tradicional tiene dificultades. Las técnicas de optimización se combinan con el MEF para conseguir la máxima atenuación posible en el rango de frecuencias de interés. Se ha definido un problema de optimización de un silenciador multicámara y se han llevado a cabo varios análisis para obtener la configuración más adecuada para cada caso. Bajo ciertas hipótesis de uniformidad axial, se han considerado varias técnicas para reducir el coste computacional de un análisis 3D completo para silenciadores disipativos con gradientes de temperatura y flujo medio. Éstas se basan en la descomposición del campo acústico en modos axiales y transversales dentro de cada subdominio, y un procedimiento de acoplamiento de las expansiones modales en los cambios de sección del silenciador mediante las condiciones de continuidad de los campos acústicos. Se estudia la eficiencia computacional y precisión de las predicciones de las técnicas de acoplamiento, incluyendo colocación puntual en nodos y puntos de Gauss, así como ajuste modal. Todos ellos proporcionan predicciones precisas de la atenuación mejorando el coste / [CAT] Aquesta Tesi es centra en el desenvolupament i implementació de mètodes numèrics eficients per al disseny i modelatge de components de la línia d'escapament en motors de combustió interna. Mereixen especial atenció els silenciadors dissipatius perforats d'automòbils, ja que el seu comportament acústic pot patir variacions importants degudes a les variacions de temperatura en el material absorbent, així com a les heterogeneïtats de la fibra. Per tant, es requereixen tècniques numèriques que considerin aquests casos per garantir la precisió dels resultats. Es porta a terme una revisió bibliogràfica que recull els models d'ona unidimensionals, així com models acústics de materials absorbents i superfícies perforades. No obstant això, les limitacions dels primers fan indispensable l'ús de models multidimensionals. A més s'explora la possibilitat d'usar nous elements acústics amb l'objectiu que siguen una alternativa potencial als materials absorbents, que poden tenir un efecte negatiu sobre la salut. La Tesi considera l'ús de superfícies microperforades i sinteritzades. Aquestes últimes en alguns casos presenten una impedància gairebé constant. El seu valor depèn, entre altres coses, del gruix i la porositat de les plaques. Per evitar les limitacions dels models d'ona plana, es proposa un enfocament amb elements finits (EF) per a l'anàlisi acústic de silenciadors dissipatius que inclouen un conducte amb flux mig axial uniforme i una càmera externa amb una distribució heterogènia de material absorbent. D'altra banda, la variació de les propietats també es pot produir per gradients tèrmics. En aquest cas, es proposa una formulació híbrida d'EF per silenciadors dissipatius perforats que inclou: (1) Gradients tèrmics en el conducte central i la càmera; (2) Un conducte perforat que canalitza flux mig axial no uniforme. S'ha implementat una formulació d'EF per resoldre l'equació d'ones en termes de pressió per al medi estacionari heterogeni associat a la càmera. A més, l'equació associada al conducte central, expressada en termes de potencial de velocitat acústica, permet la presència de flux axial no uniforme. L'acoblament entre les dues regions s'ha realitzat mitjançant un conducte perforat i la seva impedància acústica i s'ha adaptat per incloure la esmentada falta d'homogeneïtat. S'ha vist que les heterogeneïtats poden influir notablement en l'atenuació acústica d'un silenciador i s'han d'incloure en els models teòrics. Les tècniques d'optimització per a components industrials de control de soroll són importants, ja que produeixen elements amb millors característiques. Els algoritmes evolutius són tècniques emergents capaces d'obtenir una solució, fins i tot quan l'optimització tradicional té dificultats. Les tècniques d'optimització es combinen amb el mètode d'elements finits (MEF) per aconseguir la màxima atenuació possible en el rang de freqüències d'interès. S'ha definit un problema d'optimització d'un silenciador multicàmera i s'han dut a terme diverses anàlisis per obtenir la configuració més adequada per a cada cas. Sota certes hipòtesis d'uniformitat axial, s'han considerat diverses tècniques per reduir el cost computacional d'una anàlisi 3D complet per silenciadors dissipatius amb gradients de temperatura i flux mig. Aquestes es basen en la descomposició del camp acústic en modes axials i transversals dins de cada subdomini, i un procediment d'acoblament de les expansions modals en els canvis de secció del silenciador mitjançant les condicions de continuïtat dels camps acústics. S'estudia l'eficiència computacional i precisió de les prediccions de les tècniques d'acoblament, incloent col·locació puntual en nodes i punts de Gauss, així com ajust modal. Tots ells proporcionen prediccions precises de l'atenuació millorant el cost computacional d'EF. / Sánchez Orgaz, EM. (2016). Advanced numerical techniques for the acoustic modelling of materials and noise control devices in the exhaust system of internal combustion engines [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/64090 / TESIS
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Zu den Auswirkungen experimenteller Waldneugründungs- und Waldumbaumaßnahmen auf die saprophage Invertebratenfauna an extrem immissionsgeschädigten Kammlagenstandorten des Osterzgebirges (Sachsen): Oligochaeta: Enchytraeidae, Lumbricidae; Acari: Oribatida; Insecta: Collembola: Bodenzoologisch-ökologische Untersuchungen

La France, Martin 29 November 2002 (has links)
The effects of reafforestation with seedlings of spruce, birch, mountain-ash, beech and larch, partially in combination with liming and removal of the topsoil layer before planting, on the community of saprophagous invertebrates (lumbricids, enchytraeids, oribatids, collembolans) were examined. The study area was located on plateau sites of the eastern Ore Mountains (Saxonia, Germany). Investigations were carried out on study sites exposed to high sulphur dioxide immissions and reforested 3 respectively 10 years ago. Invertebrates were sampled by the extraction of soil cores and by the ?electro-octett-method? (lumbricids). Additionally, the ?minicontainer method? was used to investigate decomposition rates of different types of litter. On the control area, a diedback spruce stand, the decomposer community showed high adaptations to the acidic soil substrate and was dominated by few enchytraeid species. Long-termed loss of tree shelter, liming and topsoil removal before planting resulted in a severe decline of most saprophagous species. However, changes in invertebrate community pattern due to different plantations were not found. A comparison of leaf and needle litter decomposition rates resulted in the following order: birch (k = 0.50) &amp;gt; mountain-ash (0.40) &amp;gt; spruce (0.30) &amp;gt;&amp;gt; larch (0.12). Considering all investigated taxa, the metabolic decomposing capacity of the larch litter reached 39 %, that the spruce litter 54 % of the foliage litter results. / Anläßlich des kompletten Ausfalls der Fichte in den extrem immissionsbelasteten Kammlagen des Osterzgebirges (Sachsen) wurden im Rahmen eines interdisziplinären Verbundprojektes verschiedene Waldbaukonzepte hinsichtlich ihrer Einflüsse auf die saprophage Invertebratenfauna (Enchytraeidae, Lumbricidae, Oribatida, Collembola) untersucht. Zur Disposition standen Verfahren zur Waldneugründung (Kulturparzellen mit Reihenpflanzung von Birke, Eberesche oder Fichte; zusätzlich waldbaulich unbeeinflußte Sukzessionsparzellen) und zum Waldumbau (Kulturparzellen mit Reihenpflanzung von Buche oder Lärche nach Abtrieb und flächigem Oberbodenabschub). Ein absterbender Fichtenreinbestand in fortgeschrittener Auflösung diente als Referenz- bzw. Korrelationsmaßstab. Die Erfassung der Mesofauna erfolgte über die Extraktion von Stechrohrproben. Lumbriciden wurden mit der Elektrooktett-Methode aufgenommen. Neben der flächenbezogenen Datenerfassung wurden 1.200 mit Blattstreu von Birke, Eberesche, Fichte und Lärche befüllte Minicontainer über 19 Monate auf einer Sukzessionsparzelle exponiert, um substratspezifische Abbaugeschwindigkeiten zu ermitteln und faunistische Sukzessionsverläufe zu studieren. Die Referenzfläche zeichnete sich durch eine stark enchytraeendominierte Zersetzergemeinschaft aus, die deutliche Anzeichen einer kalkungsbedingten Überprägung erkennen ließ. Der Enchytraeenanteil an den potentiellen Umsatzleistungen der untersuchten Destruententaxa (berechnet über metabolische Äquivalenzwerte) lag bei über 90 %. Hiervon ausgehend zeigten die Zersetzergemeinschaften der Versuchsanlagen &amp;quot;Waldneugründung&amp;quot; und &amp;quot;Waldumbau&amp;quot; stark divergierende Entwicklungsrichtungen. Als ausschlaggebende Faktoren konnten Schirmverlust, Kalkung und Oberbodenbeseitigung wahrscheinlich gemacht werden. Dagegen waren Einflüsse der unterschiedlichen Kulturbaumarten kaum nachzuweisen. Die streuspezifischen Dekompositionsgeschwindigkeiten unterschieden sich wie folgt: Birke (k = 0,50) &amp;gt; Eberesche (0,40) &amp;gt; Fichte (0,30) &amp;gt;&amp;gt; Lärche (0,12). Diese vergleichsweise geringen Abbauraten stehen überwiegend mit dem rauhen Montanklima in Zusammenhang. Enchytraeen besiedelten alle Streutypen zügig, während Collembolen vor allem die Ebereschenstreu verzögert aufsuchten und mit geringster Dichte bevölkerten. Oribatiden zeigten die geringste Besiedlungsgeschwindigkeit und hatten wie die Enchytaeen in der Laubstreu signifikant höhere Wohndichten. Nur Steganacarus spinosus zeigte eine besondere Affinität für Nadelstreu. Das metabolische Leistungspotential des Destruentenbesatzes der Lärchenstreu erreichte 39 %, das der Fichtenstreu 54 % der Laubstreuresultate.
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Počítačová podpora rozpoznávání a klasifikace rodových erbů / Computer Aided Recognization and Classification of Coat of Arms

Vídeňský, František January 2017 (has links)
This master thesis describes the design and development of the system for detection and recognition of whole coat of arms as well as each heraldic parts. In the thesis are presented methods of computer vision for segmentation and detection of an object and selected methods that are the most suitable. Most of the heraldic parts are segmented using a convolution neural networks and the rest using active contours. The Histogram of the gradient method was selected for coats of arms detection in an image. For training and functionality verification is used my own data set. The resulting system can serve as an auxiliary tool used in auxiliary sciences of history.
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Nové sorpční gely pro užití v technice difúzních gradientů v tenkých filmech / New resin gels for application in DGT technique

Trávníčková, Jana January 2008 (has links)
Diffusive gradients in thin films technique (DGT) is a simple preconcetration method for in situ determination of labile metal ions in aquatic systems. It eliminates contamination problems associated with the sampling and transport into the laboratory. The DGT technique is based on a simple device that accumulates metal ions on a cation-exchange resin, immobilized in thin layer of hydrogel, after passage through the diffusion layer. The cation-exchanger, usually Chelex 100, is selective for binding free or weakly complexed metal ions in solution. This diploma thesis deals with the characterization of a new resin gel based on ion exchanger with anchored thiol-functional groups, Spheron-Thiol, for DGT technique. This new binding agent with a high selectivity for „heavy“ metal ions could provide more information on the labile metal species in water systems. The performance of DGT technique with utilization of Spheron-Thiol resin was investigated by the determination of Cd, Cu, Ni and Pb under laboratory conditions. Due to the strong adsorption of copper to the Spheron-Thiol, it is necessary to decompose the resin gel in nitric acid prior to the determination. New resin gel provides reliable information of trace metal concentrations within the pH range 6 – 8 typical for natural waters. The effect of competitive ligands, iminodiacetic and humic acids, on Cd, Cu, Ni a Pb sorption on Spheron-Thiol and Chelex 100 resin gels was determined.
340

Studium vlastností sorpčních gelů pro stanovení rtuti technikou DGT. / Characterization of the resin gels for mercury determination by DGT technique.

Finsterlová, Hana January 2009 (has links)
The aim of this thesis is testing of resin gels used in diffusive gradients in thin films technique (DGT) for determination of mercury in natural waters. The sorbets, chosen for preparation of resing gels were: Duolit GT- 73, Spheron- Thiol, and Chelex 100 and newly modified sorbent Iontosorb AV. At the beginning of work, the preparation procedure of all resing gels was optimized. After optimalization of preparation procedure the resin gels were tested in mercury model solutions. The recovery test and time dependence test were performed. When the basic tests were finished, they were followed by the tests of influence of natural ligand (humic acids and chlorides), and other parameters (above all pH and ionic strenght), on mercury determination by DGT technique.

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