935 resultados para blade trailing edge
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Construction of hydroelectric dams in tropical regions has been contributing significantly to forest fragmentation. Alterations at edges of forest fragments impact plant communities that suffer increases in tree damage and dead, and decreases in seedling recruitment. This study aimed to test the core-area model in a fragmented landscape caused by construction of a hydroelectric power plant in the Brazilian Amazon. We studied variations in forest structure between the margin and interiors of 17 islands of 8-100 hectares in the Tucuruí dam reservoir, in two plots (30 and >100m from the margin) per island. Mean tree density, basal area, seedling density and forest cover did not significantly differ between marginal and interior island plots. Also, no significant differences were found in liana density, dead tree or damage for margin and interior plots. The peculiar topographic conditions associated with the matrix habitat and shapes of the island seem to extend edge effects to the islands' centers independently of the island size, giving the interior similar physical microclimatic conditions as at the edges. We propose a protocol for assessing the ecological impacts of edge effects in fragments of natural habitat surrounded by induced (artificial) edges. The protocol involves three steps: (1) identification of focal taxa of particular conservation or management interest, (2) measurement of an "edge function" that describes the response of these taxa to induced edges, and (3) use of a "Core-Area Model" to extrapolate edge function parameters to existing or novel situations.
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Radiometric changes observed in multi-temporal optical satellite images have an important role in efforts to characterize selective-logging areas. The aim of this study was to analyze the multi-temporal behavior of spectral-mixture responses in satellite images in simulated selective-logging areas in the Amazon forest, considering red/near-infrared spectral relationships. Forest edges were used to infer the selective-logging infrastructure using differently oriented edges in the transition between forest and deforested areas in satellite images. TM/Landsat-5 images acquired at three dates with different solar-illumination geometries were used in this analysis. The method assumed that the radiometric responses between forest with selective-logging effects and forest edges in contact with recent clear-cuts are related. The spatial frequency attributes of red/near infrared bands for edge areas were analyzed. Analysis of dispersion diagrams showed two groups of pixels that represent selective-logging areas. The attributes for size and radiometric distance representing these two groups were related to solar-elevation angle. The results suggest that detection of timber exploitation areas is limited because of the complexity of the selective-logging radiometric response. Thus, the accuracy of detecting selective logging can be influenced by the solar-elevation angle at the time of image acquisition. We conclude that images with lower solar-elevation angles are less reliable for delineation of selecting logging.
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Glandular trichomes play a major role in the morphological characterization of the Bignoniaceae. Due to their great diversity of forms and functions, this study aimed to inventory the glandular trichomes present in the aerial vegetative axis of Amphilophium magnoliifolium, Martinella obovata and Stizophyllum riparium, analyze their structure and register the participation of ants in these plants. Fresh samples from the nodal region, petiole and from medium to apical regions of the leaflet blade were fixed and processed according to usual methods in light and scanning electron microscopies. The glandular trichomes found were: peltate, capitate, stipitate, and patelliform/cupular. Peltate trichomes are the most abundant ones and present the most uniform distribution. Patelliform/cupular trichomes occur at specific regions, such as prophylls, leaflet blade and nodal regions. Martinella obovata is the only species that presents capitate and stipitate trichomes, which are widely distributed along the entire aerial vegetative axis. Ants were found in all species, mainly at nodal regions. The occurrence of the capitate-type trichome is reported for the first time to the genus.
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ABSTRACTIn the Amazon, river navigation is very important due to the length of navigable rivers and the lack of alternative road networks. Boats usually operate in unfavorable conditions, since there is no hydrodynamic relation among propellers, geometry, and the dimensions of the boat hull. Currently, there is no methodology for propeller hydrodynamic optimization with low computational cost and easy implementation in the region. The aim of this work was to develop a mathematical approach for marine propeller design applied to boats typically found on Amazon rivers. We developed an optimized formulation for the chord and pitch angle distributions, taking into account the classical model of Glauert. A theoretical analysis for the thrust and torque relationships on an annular control volume was performed. The mathematical model used was based on the Blade Element Momentum Theory (BEMT). We concluded that the new methodology proposed in this work demonstrates a good physical behavior when compared with the theory of Glauert and the experimental data of the Wageningen B3-50 propeller.
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ABSTRACT Leaves have a variety of morphological and anatomical characters mainly influenced by climatic, edaphic and biotic factors. The aim of this study was to describe the anatomical leaf traits of Qualea parviflora from three phytophysiognomies. The studied phytophysiognomies were Amazon Savannah on rocky outcrops (ASR), Transition Rupestrian Cerrado (TRC), and Cerradão (CDA). Freehand sections of the leaf blade were made and stained with 0.5% astra blue and with basic fuchsin. From the adaxial and abaxial leaf surface, freehand paradermal sections were made for epidermis analysis. The Jeffrey´s method, with modifications, was used in the epidermis dissociation process. The samples from the TRC phytophysiognomy had relatively smaller ordinary epidermal cells, higher abundance of trichomes, and mesophyll with few intercellular spaces, in comparison to the other phytophysiognomies. The leaves from the ASR phytophysiognomy had higher stomatal index (SI = 21.02), and five to six layers of sclerenchyma surrounding the midrib vascular bundle. The secondary vascular bundles had thicker cell walls and the bundle sheath extended up to the epidermal tissue of both leaf sides. Leaves from the CDA phytophysiognomy had mesomorphic environmental traits, such as a thinner cuticle. It is concluded that trees from ASR and TRC phytophysiognomies have xeromorphic traits following the environmental conditions where they occur.
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Tese de Doutoramento em Ciências da Literatura (área de especialização em Literatura Comparada).
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Mathematical and computational models play an essential role in understanding the cellular metabolism. They are used as platforms to integrate current knowledge on a biological system and to systematically test and predict the effect of manipulations to such systems. The recent advances in genome sequencing techniques have facilitated the reconstruction of genome-scale metabolic networks for a wide variety of organisms from microbes to human cells. These models have been successfully used in multiple biotechnological applications. Despite these advancements, modeling cellular metabolism still presents many challenges. The aim of this Research Topic is not only to expose and consolidate the state-of-the-art in metabolic modeling approaches, but also to push this frontier beyond the current edge through the introduction of innovative solutions. The articles presented in this e-book address some of the main challenges in the field, including the integration of different modeling formalisms, the integration of heterogeneous data sources into metabolic models, explicit representation of other biological processes during phenotype simulation, and standardization efforts in the representation of metabolic models and simulation results.
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Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Informática Médica)
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Surgical procedures such as osteotomy and hip replacement involve the cutting of bone with the aid of various manual and powered cutting instruments including manual and powered bone saws. The basic mechanics of bone sawing processes are consistent with most other material sawing processes such as for wood or metal. Frictional rubbing between the blade of the saw and the bone results in the generation of localised heating of the cut bone. Research studies have been carried out which consider the design of the bone saw which deals with specifics of the saw teeth geometry and research which examines the effect of drilling operations on heating of the bone has shown that elevated temperatures will occur from frictional overheating. This overheating in localised areas is known to have an impact on the rate of healing of the bone post operation and the sharpness life of the blade. The purpose of this study was to measure the temperature at three zones at fixed intervals of 3mm, 6mm, and 9mm away from the cutting zone. It should be noted that it was the first time that this measurement technique was used to measure the temperature gradient through the bone specimen thereby establishing the extent to which clinicians are experiencing thermal injury during sawing of bone while using a reciprocating saw. The effect of various cutting feed rate on temperature elevation was also investigated in this research. The results showed that there will be a region of bone at least 9mm either side of the cutting blade experiencing thermal injury as temperatures in this region exceeded the threshold temperature of 44°C for necrosis (cell death).
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In today’s world, many companies are concentrating on both their technology and human resources to provide them with their competitive advantage. Hence, understanding what motivates people is particularly important for managers in order to develop and sustain a competitive edge. As a result, numerous theories have been advanced to help our understanding of the subject matter and from these theories many motivational methods have evolved to enhance motivation within the workplace. In addition, research has been conducted on the various types of motivational techniques utilised by companies within Ireland. However, very little research has been completed within specific geographical regions in Ireland concerning the types of motivational techniques implemented at different job levels and their impact on employees work performance. Thus the objective of this research was to identify the motivational techniques utilised at different job levels within large manufacturing and service companies in the Northwest of Ireland and examine how these techniques influence the performance levels of employees. Furthermore, the study examined if these companies have changed from traditional ways of motivating employees to newer techniques. The research methodologies used to undertake the research included interviews with the HR managers and questionnaires completed by different employees at various job levels within the participating companies. Overall the conclusions were varied. Many different types of motivation techniques were found within the study’s participating companies. Irish companies are improving their motivational techniques, however most of these techniques are only used within higher job levels. In contrast to their American counterparts, a variety of motivational techniques are utilised and implemented at all job levels. On a more positive note, the majority of these motivational techniques do increase performance levels at all job levels. From the extensive primary and secondary research conducted, the thesis concludes by offering a number of recommendations to assist companies in further development of their motivational techniques for all job levels. These recommendations hope to augment the success of companies through an enhanced motivated workforce.
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This thesis details the findings of a study into the spatial distribution and speciation of 238U, 226Ra and 228Ra in the soils of the Cronamuck valley, County Donegal . The region lies on the north-eastern edge of the Barnesmore granite and has been the subject of uranium prospecting efforts in the past. The results of the project provide information on the practicability of geostatistical techniques as a means of estimating the spatial distribution of natural radionuclides and provide insight into the behaviour of these nuclides and their modes of occurrence and enrichment in an upland bog environment. The results of the geostatistical survey conducted on the area indicate that the primary control over the levels of the studied nuclides in the soil of the valley is the underlying geology. Isopleth maps of nuclide levels in the valley indicate a predominance of elevated nuclide levels in the samples drawn from the granite region, statistical analysis of the data indicating that levels of the nuclides in samples drawn from the granite are greater than levels drawn from the non-granite region by up to a factor of 4.6 for 238U and 4.9 for 226Ra. Redistribution of the nuclides occurs via drainage systems within the valley, this process being responsible for transport of nuclides away from the granite region resulting in enrichment of nuclides in soils not underlain by the granite. Distribution of the nuclides within the valley is erratic, the effect of drainage f lows on the nuclides resulting in localized enriched areas within the valley. Speciation of the nuclides within one of the enriched areas encountered in the study indicates that enrichment is as a result of saturation of the soil with drainage water containing trace amounts of radionuclides. 238U is primarily held within the labile fractions (exchangeable cat ions + easily oxidisable organics + amorphous iron oxides ) of the soil , 226Ra being associated with the non- labile fractions, most probably the resistant organic material. 228Ra displays a significant occurrence in both the labile and non- labile fractions. The ability of the soil to retain uranium appears to be affected largely by the redox status of the soil, samples drawn from oxidizing environments tending to have little or no uranium in the easily oxidisable and amorphous iron oxide fractions. This loss of uranium from oxidised soil samples is responsible for the elevated 226Ra /238U disequilibrium encountered in the enriched areas of the valley. Analysis of the data indicates that samples displaying elevated 226Ra/238U ratios also exhibit elevated 228Ra/238U ratios indicating a loss of uranium from the samples as opposed to an enrichment of 226Ra.
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Quality Management is a well-developed and widely used approach within industry to gain competitive edge and increased market share. It is a new management approach for schools who are now applying it without having the culture or experience of its evolution. Industrially based Quality management systems and excellence models have been developed. These excellence models and frameworks are based on the principles and concepts of TQM which are recognised as essential elements of high performing organisations. Schools are complex social institutions that provide a service. Like any other service industry, the customers of education are expecting and demanding a better service or else they will go elsewhere. Schools are beginning to reform and change to adapt to such demands. This has been reflected in Ireland in the Education Act, 1998. It is now the right time to develop a quality management system specifically for schools. The existing industrial excellence models have been modified for use in the private and public sector and some have been specifically tailored for education. The problem with such models is that they are still too sophisticated and the language still too industrial for schools. This Thesis develops and Excellence Model for Second Level Schools and provides guidance and school specific tools for its implementation.
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This project was funded under the Applied Research Grants Scheme administered by Enterprise Ireland. The project was a partnership between Galway - Mayo Institute of Technology and an industrial company, Tyco/Mallinckrodt Galway. The project aimed to develop a semi - automatic, self - learning pattern recognition system capable of detecting defects on the printed circuits boards such as component vacancy, component misalignment, component orientation, component error, and component weld. The research was conducted in three directions: image acquisition, image filtering/recognition and software development. Image acquisition studied the process of forming and digitizing images and some fundamental aspects regarding the human visual perception. The importance of choosing the right camera and illumination system for a certain type of problem has been highlighted. Probably the most important step towards image recognition is image filtering, The filters are used to correct and enhance images in order to prepare them for recognition. Convolution, histogram equalisation, filters based on Boolean mathematics, noise reduction, edge detection, geometrical filters, cross-correlation filters and image compression are some examples of the filters that have been studied and successfully implemented in the software application. The software application developed during the research is customized in order to meet the requirements of the industrial partner. The application is able to analyze pictures, perform the filtering, build libraries, process images and generate log files. It incorporates most of the filters studied and together with the illumination system and the camera it provides a fully integrated framework able to analyze defects on printed circuit boards.
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In Ireland, although flatfish form a valuable fishery, little is known about the smallest, the dab Limanda limanda. In this study, a variety of parameters of reproductive development, including ovarian phase description, gonadosomatic index (GSI), hepatosomatic index (HSI), relative condition (Kn) and oocyte size were analysed to provide information on the dab’s reproductive cycle and spawning periods. Sampling were collected monthly over an 18-month period using bottom trawls of the Irish coastline. A six phase macroscopic guide was developed for both sexes of dab, and verified using histology. In comparisons of macroscopic and microscopic phases, there was high agreement in the proposed female guide (86%), with males demonstratively lower (62%). No significant bias was observed between the the two reproductive methods. When the male macroscopic guide was examined, misclassification was high in phase 5 and phase 5 (41%), with 96% of misclassification occurring in adjacent phases. The sampled population was primarily composed of females, with ratios of females to males 1:0.6, although the predominance of females was less noticeable during the reproductive season. Oocyte growth in dab follows asynchronous development, and spawn over a protracted period indicating a batch spawning strategy. Spawning occurred mainly in early spring, with total regeneration of gonads by May. The length at which 50% of the population was reproductively mature was identified as 14cm and 17cm, for male and female dab, respectively. Precision and bias in age determinations using whole otoliths to age dab was investigated using six age readers from various institutions. Low levels of precision were obtained (CV: 10-23%) inferring the need for an alternative methodology. Precision and bias was influence by the level of experience of the reader, with ageing error attributed to interpretative differences and difficulty in edge determination. Sectioned otolith age determinations were subsequently compared to whole otolith age determinations using two age readers experienced in dab ageing. Although increased precision was observed in whole otoliths from previous estimates (CV=0%, 0% APE), sectioned otoliths were used for growth models. This was based on multinominal logistic regression on age length keys developed using both ageing methods. Biological data (length and age) for both sexes was applied to four growth models, where the Akaike criterion and Multi model Inference indicated the logistic model as having the best fit to the collected data. In general, female dab attained a longer length then males, with growth rates significantly different between the two sexes. Length weight relationships between the two sexes were also significantly different.
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The author has studied the domatia appearing in the Rubiaceae family by examining 622 species distributed among 113 genera; and has verified that 88 species belonging to 35 genera have domatia fitting in the "touffe de poils", "en pertuis" and "em pochette" types according to the Chevalier's Classification. 39 species present domatia that display chamber, duct and outlet orifice. The other 46 species present domatia either as hair-agglomerates, hair-clusters or scattered hairs. The domatia in Paveta indica L. and Vangueria edulis Vahl. are in the shape of a little holow in the blade tissue and have no hairs. In Borreria verbenoides Cham & Schl. the domatia are formed by an elevation in the limb and presents abundant and short hairs. In Bqthryopora corymbosa Hook f. and Gardenia Thumbergii L. the domatia appear also in the nervure axils of several orders and also in Rudgea lanceolata Benth., Rudgea subsessilis Benth. and Rudgea gardenoides Muell. Arg. are they located7 in the axilla of the angle directed toward the leaf base.