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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

Hodnocení individuálního herního výkonu ve fotbale u hráčů kategorie U10 / Assessment of individual game performance in football players U10

Kuta, Marek January 2021 (has links)
Name: Assessment of individual game performance in football players U10 Objectives: The aim of the thesis is to analyse the success rate of the chosen playing skills in competitive matches in the U10 category in football. Methods: The researched group was made of fifteen individuals, including two goalkeepers, with the average age 10 years, ± 0,5 year. The individuals were observed and evaluated in five matches. The method of analysis was used to gather the data. The data were taken down by the scale system and written into the recording sheet. Three football skills were chosen for the research - pass, dribbling past the opponent, and ball reception. Nonparametric coefficient r was used for the determination of material significance of the differences. Results: Much higher success rate of the pass was discovered on the defensive half in comparison to the attacking half (85,84 % vs. 72,37 %; r = 0,83). Dribbling past the opponent was more frequent on the attacking half in comparison to the defensive half (28,37 vs. 21,67; coefficient r = 0,78), however, there was not any significant difference in the success on the attacking half in comparison to the defensive half (57,39 % vs. 53,39 %; coefficient r = 0,27). Player's passes were more successful compared to their dribbling-past-the-opponent skill...
12

Development of Cellulose-Titanium dioxide-Porphyrin Nanocomposite Films with High-barrier, UV-blocking, and Visible Light-Responsive Antimicrobial Features

Lovely, Belladini 03 June 2024 (has links)
The packaging does not serve as a mere containment but also can be designed to play a key role in preserving the product from quality-deteriorating factors, including oxygen, light irradiation, and foodborne pathogenic microorganisms (e.g., Escherichia coli). There has been a growing interest in employing ultra-porous metal-organic frameworks (MOF) with visible light-responsive antibacterial mechanisms to generate reactive oxygen species (ROS) that can eliminate bacteria via an oxidative burst. MOF is made of inorganic metal ions/nodes/clusters/secondary building units linked by organic bridge ligands, where titanium dioxide (TiO2) and tetrakis(4-carboxyphenyl)porphyrin) (TCPP) were selected for these components, respectively. TiO2 is an exceptional UV-A/B/C-blocker; meanwhile, TCPP dye performs a remarkable photocatalytic ability even under visible light, on top of its macro-heterocyclic structure that is ideal as a MOF linker. Both have good compatibility but suffer from the notorious tendency to self-quench/aggregate. The incorporation of MOF-based conjugates into a polymeric matrix, like cellulose, is among the proven-successful solutions. Cellulose is the Earth's most abundant and naturally biodegradable, and cellulose nanofibril (CNF) was particularly chosen for its high specific surface area and surface activity. However, a straightforward, cheap, and environmentally friendly approach of multicycle homogenization (0-25 passes) was conducted to solve neat cellulose's challenge of natural hydrophilicity, where low pressure (<10 MPa) was applied to prevent the common over-shearing effect. The antibacterial efficacy of CNF films functionalized with TiO2-TCPP conjugate on inhibiting E. coli growth was analyzed with and without light of different intensities (3000 and 6000 lux). The positive impacts of CNFs' promoted fibrillation and subsequent inter/intra-molecular hydrogen bonding post-homogenization were evidenced in an array of functional properties, i.e., crystallinity, TiO2-TCPP conjugate dispersion, surface smoothness, mechanical properties, thermal stability, hydrophobicity, oxygen barrier (comparable to ethylene-vinyl alcohol (EVOH), a commercial high-barrier polymer), and 100%-antibacterial rate (under 6000 lux after 72 hours). Varying optimum cycles of homogenization demonstrated the prospect of the proposed homogenization approach in preparing CNF with diverse processability and applicability. These findings also exhibited a promising potential for a myriad of high-barrier, UV-blocking, and/or visible light-responsive antibacterial film applications, including food packaging and biomedical. / Doctor of Philosophy / Packaging is useful not only as a container but can also be designed to help prevent products from being spoiled due to various reasons such as oxidation, light, and bacterial contamination. Researchers have discovered the promising antibacterial feature of the metal-organic framework (MOF). Packaging made with MOF technology can harness light and oxygen in the environment to produce a special form of oxygen called reactive oxygen species (ROS) that can kill unwanted bacteria. MOF is an extremely porous sponge-like material made of two ingredients: an inorganic metal cluster and an organic linker; in this study, titanium dioxide (TiO2) and a porphyrin called TCPP were selected, respectively. TiO2 is an excellent ultraviolet blocker, while TCPP has a unique, ring-like geometry that is ideal for use as a linker and an antimicrobial feature that works well under the visible light spectrum. The pair are compatible but still suffer from MOF's notorious challenge, where it tends to clump together because of its tiny size. To resolve this problem, TiO2-TCPP MOF can be deposited evenly in a cast made of polymer. Cellulose has been proven to work effectively as a polymeric cast; moreover, it is natural, biodegradable, and in abundant supply. A type of nanosized cellulose—cellulose nanofibril (CNF)—was specifically chosen because its high surface area and activity are useful when blended with other materials. However, cellulose is naturally a poor water-repellant that is not ideal for packaging applications. As a solution, cellulose can be treated with a homogenization technique by passing the material through a very narrow hole under high pressure. Homogenization can be problematic as it possibly damages the cellulose's structure, and its high pressure can also be expensive and energy consuming. Therefore, low pressure with multiple cycles was applied in this work. CNF-TiO2-TCPP films were tested for their ability to slow down E. coli bacteria growth with and without light of varying brightness to compare its light-sensitive antimicrobial feature. Homogenization was found helpful in producing higher-quality CNF, which improved several of the film's final characteristics, including an even material dispersion, structural order, smoothness, strength, heat resistance, and water repellency. Most importantly, it produced films with oxygen barrier ability comparable to commercial high-barrier plastics and completely eliminated bacteria after 72 hours. The optimum number of homogenization cycles was found to be dependent on the desired characteristics and application. Overall, these findings carry a promising potential for a variety of applications, including food packaging and the biomedical field.
13

Soldabilidade metalúrgica do aço ASTM A553 tipo I com 9% de ní­quel. / Metallurgical weldability of ASTM A553 Type I steel with 9% nickel.

Jaime Casanova Soeiro Junior 06 December 2017 (has links)
A soldagem altera as propriedades mecânicas dos aços ligados ao níquel, em especial seu desempenho em aplicações criogênicas. Assim, este trabalho apresenta um estudo sobre a soldabilidade metalúrgica do aço com 9% níquel e tem como objetivos: identificar se a fragilização em temperatura abaixo da temperatura Ac3 ocorre em ZACs com dois e três ciclos térmicos simulados fisicamente; analisar as características da junta soldada pelo processo de soldagem por atrito linear com mistura e os efeitos da soldagem multipasse; e analisar a influência dos passes de enchimento e acabamento sobre o comportamento mecânico da ZAC da raiz de uma junta soldada pelo processo de soldagem MIG/MAG. Destacam-se entre os resultados da simulação física da ZAC: as amostras que tiveram a temperatura máxima abaixo da temperatura Ac1, no terceiro ciclo térmico, não apresentaram o efeito de redução da energia absorvida no ensaio Charpy V; a fração volumétrica de austenita retida não aumenta a quantidade de energia absorvida no ensaio Charpy V para as amostras que tiveram a temperatura máxima do segundo ciclo térmico abaixo da temperatura Ac3 (723°C); e a correlação linear múltipla sugere um modelo empírico, baseado nos dados deste trabalho, onde os fatores de fração volumétrica do microconstituinte martensita-austenita, fração volumétrica de austenita retida e tamanho de grão são mais relevantes para a quantidade de energia absorvida no ensaio Charpy V. Destacam-se entre os resultados da soldagem por atrito linear: a energia absorvida no ensaio Charpy V da zona misturada do primeiro cordão (CP1) é menor que o metal de base; o segundo cordão gera duas regiões na zona misturada do primeiro cordão, que tendem a aumentar a energia absorvida no ensaio Charpy V; os valores de energia absorvida no ensaio Charpy V apresentam correlações lineares simples com a microdureza, a fração volumétrica do microconstituinte martensita-austenita e com o tamanho de grão. Destacam-se entre os resultados da soldagem com MIG/MAG: A soldagem do aço com 9% de níquel com a liga Inconel 625 gera uma zona não misturada entre o metal de solda e a ZAC; a amostra com todos os passes de solda (CP3) apresenta a menor energia absorvida no ensaio Charpy V entre todos os experimentos; e a trinca, no ensaio Charpy V, propaga na zona não misturada no CP1 e no CP2, que tiveram as maiores energias absorvidas no ensaio Charpy. O CP3 apresenta propagação de trinca na linha de fusão e possui a menor energia absorvida no ensaio Charpy V. / Welding modify the mechanical properties of nickel steels, especially their performance in cryogenic applications. Thus, this work presents a study on the metallurgical weldability of 9% nickel steel and its objectives are: identify if the embrittlement in temperature below the Ac3 temperature occurs in HAZs with two and three thermal cycles simulated physically; analyze the characteristics of the joint welded by friction stir welding process and the effects of multipass welding; and analyze the influence of the filling and finishing passes on the mechanical behavior of HAZ from the root of a joint welded by the GMAW welding process. The results of the physical simulation of the HAZ were: the samples that had the maximum temperature below the temperature Ac1, in the third thermal cycle, did not present the effect of reduction of the energy absorbed in the Charpy V test; the retained austenite volumetric fraction does not increase the amount of energy absorbed in the Charpy V test for the samples having the maximum temperature of the second thermal cycle below the Ac3 temperature (723 °C); and the multiple linear correlation suggests an empirical model, based on the data of this work, where the volumetric fraction factors of the martensite-austenite microconstituent, retained austenite volumetric fraction and grain size are more relevant for the amount of energy absorbed in the Charpy V test. The FSW welding highlights results: the energy absorbed in the Charpy V test of the mixed zone of the first pass (CP1) is smaller than the base metal; the second pass generates two regions in the mixed zone of the first pass, which tend to increase the energy absorbed in the Charpy V test; the values of energy absorbed in the Charpy V test show simple linear correlations with the microhardness, the volumetric fraction of the martensite-austenite microconstituent and with the grain size. The GMAW welding highlights results: welding of the steel with 9% nickel with the Inconel 625 alloy makes an unmixed zone between the weld metal and the HAZ; the sample with all weld passes (CP3) shows the lowest energy absorbed in the Charpy V test among all the experiments; and the crack, in the Charpy V test, propagates in the unmixed zone in CP1 and CP2, which had the highest energies absorbed in the Charpy test. The CP3 shows crack propagation in the melting line and has the lowest energy absorbed in the Charpy V test.
14

Soldabilidade metalúrgica do aço ASTM A553 tipo I com 9% de ní­quel. / Metallurgical weldability of ASTM A553 Type I steel with 9% nickel.

Soeiro Junior, Jaime Casanova 06 December 2017 (has links)
A soldagem altera as propriedades mecânicas dos aços ligados ao níquel, em especial seu desempenho em aplicações criogênicas. Assim, este trabalho apresenta um estudo sobre a soldabilidade metalúrgica do aço com 9% níquel e tem como objetivos: identificar se a fragilização em temperatura abaixo da temperatura Ac3 ocorre em ZACs com dois e três ciclos térmicos simulados fisicamente; analisar as características da junta soldada pelo processo de soldagem por atrito linear com mistura e os efeitos da soldagem multipasse; e analisar a influência dos passes de enchimento e acabamento sobre o comportamento mecânico da ZAC da raiz de uma junta soldada pelo processo de soldagem MIG/MAG. Destacam-se entre os resultados da simulação física da ZAC: as amostras que tiveram a temperatura máxima abaixo da temperatura Ac1, no terceiro ciclo térmico, não apresentaram o efeito de redução da energia absorvida no ensaio Charpy V; a fração volumétrica de austenita retida não aumenta a quantidade de energia absorvida no ensaio Charpy V para as amostras que tiveram a temperatura máxima do segundo ciclo térmico abaixo da temperatura Ac3 (723°C); e a correlação linear múltipla sugere um modelo empírico, baseado nos dados deste trabalho, onde os fatores de fração volumétrica do microconstituinte martensita-austenita, fração volumétrica de austenita retida e tamanho de grão são mais relevantes para a quantidade de energia absorvida no ensaio Charpy V. Destacam-se entre os resultados da soldagem por atrito linear: a energia absorvida no ensaio Charpy V da zona misturada do primeiro cordão (CP1) é menor que o metal de base; o segundo cordão gera duas regiões na zona misturada do primeiro cordão, que tendem a aumentar a energia absorvida no ensaio Charpy V; os valores de energia absorvida no ensaio Charpy V apresentam correlações lineares simples com a microdureza, a fração volumétrica do microconstituinte martensita-austenita e com o tamanho de grão. Destacam-se entre os resultados da soldagem com MIG/MAG: A soldagem do aço com 9% de níquel com a liga Inconel 625 gera uma zona não misturada entre o metal de solda e a ZAC; a amostra com todos os passes de solda (CP3) apresenta a menor energia absorvida no ensaio Charpy V entre todos os experimentos; e a trinca, no ensaio Charpy V, propaga na zona não misturada no CP1 e no CP2, que tiveram as maiores energias absorvidas no ensaio Charpy. O CP3 apresenta propagação de trinca na linha de fusão e possui a menor energia absorvida no ensaio Charpy V. / Welding modify the mechanical properties of nickel steels, especially their performance in cryogenic applications. Thus, this work presents a study on the metallurgical weldability of 9% nickel steel and its objectives are: identify if the embrittlement in temperature below the Ac3 temperature occurs in HAZs with two and three thermal cycles simulated physically; analyze the characteristics of the joint welded by friction stir welding process and the effects of multipass welding; and analyze the influence of the filling and finishing passes on the mechanical behavior of HAZ from the root of a joint welded by the GMAW welding process. The results of the physical simulation of the HAZ were: the samples that had the maximum temperature below the temperature Ac1, in the third thermal cycle, did not present the effect of reduction of the energy absorbed in the Charpy V test; the retained austenite volumetric fraction does not increase the amount of energy absorbed in the Charpy V test for the samples having the maximum temperature of the second thermal cycle below the Ac3 temperature (723 °C); and the multiple linear correlation suggests an empirical model, based on the data of this work, where the volumetric fraction factors of the martensite-austenite microconstituent, retained austenite volumetric fraction and grain size are more relevant for the amount of energy absorbed in the Charpy V test. The FSW welding highlights results: the energy absorbed in the Charpy V test of the mixed zone of the first pass (CP1) is smaller than the base metal; the second pass generates two regions in the mixed zone of the first pass, which tend to increase the energy absorbed in the Charpy V test; the values of energy absorbed in the Charpy V test show simple linear correlations with the microhardness, the volumetric fraction of the martensite-austenite microconstituent and with the grain size. The GMAW welding highlights results: welding of the steel with 9% nickel with the Inconel 625 alloy makes an unmixed zone between the weld metal and the HAZ; the sample with all weld passes (CP3) shows the lowest energy absorbed in the Charpy V test among all the experiments; and the crack, in the Charpy V test, propagates in the unmixed zone in CP1 and CP2, which had the highest energies absorbed in the Charpy test. The CP3 shows crack propagation in the melting line and has the lowest energy absorbed in the Charpy V test.
15

The Influence of Shared Mobility and Transportation Policies on Vehicle Ownership: Analysis of Multifamily Residents in Portland, Oregon

Bertini Ruas, Edgar 19 March 2019 (has links)
Since the beginning of the 21st Century, the world has seen the rapid development of the so-called "sharing economy" or collaborative consumption (Botsman, 2010). One of the first areas affected by the shared economy is vehicle ownership. With the emergence of several new providers of mobility services, such as Uber and car2go, there has been the promise of changes to the traditional way of owning and using a vehicle (Wong, Hensher, & Mulley, 2017). One potential consequence of shared mobility services is the reduction in vehicle ownership. At the same time, cities are trying to anticipate these changes by reducing the amount of space dedicated to parking, including parking requirements for residential developments. This thesis aims to assess the extent to which new shared mobility services (specifically, carsharing, bikesharing, and ridehailing) and travel demand management strategies (especially parking requirements and transit pass availability) relate to vehicle ownership among residents of multifamily dwellings. To do this, we use a web-based survey targeted to residents of multifamily apartments from Portland, Oregon. With these data, we built a multinomial logistic of the number of the vehicles owned as a function of socio-demographics, built environment, parking supply, transit passes, and three forms of shared mobility services. Results suggest that there is a strong association between shared mobility use and car ownership. However, it is not as significant as the effects of income, household size, distance to work, transit pass ownership, or even parking availability. Carshare use was negatively associated with the number of household vehicles, suggesting that it may be a useful tool in reducing car ownership. For respondents with higher education and income levels, increased carshare use was associated with fewer cars. Ridehail use, however, was not as clearly associated with reducing vehicle ownership and the effect was much smaller than that of carsharing. Parking availability in the building also has a significant and positive association with vehicle ownership. In sites with no parking available, there is an increased chance of the household owning less than two or more vehicles. However, this effect seems to disappear with the increased use of shared mobility. For all income levels, monthly use of ridehail and carshare between two and three times may decrease the odds of owning two or more vehicles. The use of both options, relaxing parking requirements and shared mobility availability, seems the best strategy to reduce vehicle ownership. In the short term, it is an alternative to those residents that decide to get rid of one or all cars but still are not ready to give up using cars. For the long term, a new relationship with vehicle ownership can be built now for the younger generation.
16

Vers la modélisation des phénomènes de recristallisation en conditions multi-passes : application à l'acier 304L

Huang, Ke 15 December 2011 (has links) (PDF)
La recristallisation, qui peut se produire de façon dynamique ou statique, est un important phénomène qui transforme la microstructure des matériaux métalliques déformés modifiant ainsi ses propriétés mécaniques. Malgré l'existence de travaux approfondis sur la modélisation numérique du phénomène de recristallisation, la littérature scientifique manque de modèles précis capables de prédire l'évolution microstructurale dans des conditions de mise en forme multi passes. Bien que des efforts aient été réalisés dans cette direction, la plupart des modèles existants dans la littérature présentent soit un manque de validation expérimentale, soit ne fournissent que des accords qualitatifs entre les résultats numériques et expérimentaux dans des conditions de déformations connues et sélectionnées. De plus, les relations entre la recristallisation statique (SRX), la recristallisation dynamique (DRX), la recristallisation post-dynamique (PDRX) et la croissance de grains (GG) sont généralement trop simplistes. Par ailleurs, la plupart de ces modèles ne sont pas conçus pour la réalisation de simulations avec des conditions thermiques et/ou mécaniques variables et limite par conséquent leur utilisation pour des applications industrielles. Pour cette étude, un modèle à champ moyen 2 sites a été développé afin de décrire l'évolution microstructurale de l'acier 304L. L'originalité de ce modèle réside dans : (a) l'interaction de chaque grain avec deux milieux homogènes équivalents, avec respectivement une densité de dislocation élevée et faible; (b) le poids relatif de chaque milieu est lié à leur fraction volumique ; (c) la germination et la disparition des grains rendent la microstructure variable au cours du temps ; (d) les paramètres dépendent de la température et de la vitesse de déformation mais pas de la taille des grains dans les conditions DRX, et uniquement de la témpérature dans les conditions statiques (SRX/PDRX/GG); (e) des accords quantitatifs avec les résultats expérimentaux sont obtenus en fonction de (i) la cinétique de recristallisation, (ii) la courbe contrainte-déformation, (iii) taille de grain après recristallisation, et (f) le modèle a été développé pour être utilisé en conditions multi- passes, avec des valeurs variables de température et de vitesse de déformation. Afin de vérifier et valider le modèle, plusieurs essais de tractions ont été réalisés sous de nombreuses conditions différentes de température et de vitesse de déformation, afin de caractériser le mode DRX. Pour la vérification de la SRX et PDRX, des traitements de recuit ont été réalisés après la déformation plastique, respectivement à froid et à chaud. Les paramètres du modèle ont premièrement été estimés à partir des donnés expérimentales ou présentes dans la littérature, et ont ensuite été établis par analyse inverse. Il a été constaté que tous les paramètres du modèle évoluent de manières physiquement cohérentes en fonction de la température et de la vitesse de déformation. Les résultats obtenus à partir de la simulation de la DRX, SRX/PDEX/GG ont été analysés, en prenant en compte les effets de la température de déformation, la vitesse de déformation, la déformation appliquée ainsi que la taille de grain initiale. Un bon accord entre les résultats numériques et expérimentaux a été observé pour les différents types de recristallisation, ce qui ouvre la voie à la modélisation de la mise en forme en conditions multi passes pour des applications industrielles. Finalement, des traitements thermiques avec analyse in situ ont été réalisés afin d'obtenir une meilleure compréhension des mécanismes de SRX/PDRX/GG. Le rôle du maclage pendant le traitement de recuit a été discuté : il semble favoriser à la fois la germination et la migration des joints de grains.
17

Análises de sistemas de secagem: solar, elétrico e misto na produção de banana passa. / Analysis of Drying Systems: Solar, Electric and Mixed on the production of dried banana.

LIMA, Wellington Sousa. 13 June 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-13T19:01:17Z No. of bitstreams: 1 WELLINGTON SOUSA LIMA – TESE (PPGEP) 2016.pdf: 9442067 bytes, checksum: da59f22d2d376fa121ab8bae0ba8d2e4 (MD5) / Made available in DSpace on 2018-06-13T19:01:17Z (GMT). No. of bitstreams: 1 WELLINGTON SOUSA LIMA – TESE (PPGEP) 2016.pdf: 9442067 bytes, checksum: da59f22d2d376fa121ab8bae0ba8d2e4 (MD5) Previous issue date: 2017-03-17 / Este trabalho apresenta um estudo comparativo de sistemas de secagem para produção de banana passa. Foram utilizados um secador solar de exposição indireta com sistema de aquisição e controle das propriedades termodinâmicas do ar de secagem, e um secador elétrico automatizado com sistema de supervisão e controle embarcados . Os sistemas de secagem estudados neste trabalho foram: secagem solar, secagem elétrica e secagem mista (secagem solar seguida de secagem elétrica). Os testes experimentais foram realizados na UFCG em Campina Grande, PB, para secagem de banana prata (Musa spp.). O produto final obtido pelos três sistemas de secagem apresentou boa qualidade em relação ao aspecto visual, com um percentual de umidade em base úmida menor que 25%, compatível com o recomendado pela Resolução RDC n° 272/05 da ANVISA. O sistema de aquisição e controle de dados, como inovação no secador solar, utilizando a plataforma Arduino, garantiu a medição de temperatura e umidade relativa do ar de secagem nas entradas e saídas do coletor solar e da câmara de secagem, e também o acionamento e controle da convecção forçada no sistema de secagem para manter a temperatura no interior da câmara de secagem entre 40ºC e 60ºC. Como resultado, são apresentados os valores obtidos para rendimento do secador solar, consumo específico de energia (CEE), eficiência do processo de secagem e tempo de secagem. Por meio dos experimentos com o secador solar e com o secador elétrico foram obtidas as curvas de cinética de secagem da banana. Os resultados foram comparados e mostraram que o modelo matemático de Page é apropriado para predizer o tempo de secagem. O coeficiente de determinação (R²) obtido na secagem elétrica, na secagem mista e na secagem solar com controle, foram superiores ao obtido na secagem solar sem controle, isso demostra a importância do controle das propriedades termodinâmicas nos processos de secagem. Com relação ao CEE, o processo de secagem elétrica apresentou um CEE de 379,33 kWh por ciclo com temperatura de 45ºC e 225,54 kWh por ciclo com temperatura de 55ºC. Por outro lado o processo de secagem mista apresentou um CEE de 295,87 kWh por ciclo, a uma temperatura de 45ºC, e o processo de secagem solar apresentou um CEE médio de 45,83 kWh por ciclo. Isso mostra a grande vantagem comparativa do secador solar em relação ao secador elétrico. Com relação à eficiência mássica para os três processos de secagem, os mesmos apresentaram eficiências mássicas equivalentes em torno de 89%, o que já era esperado. Com relação aos rendimentos térmicos do secador solar, obtidos nos processos de secagem solar com controle e sem controle da temperatura , foram respectivamente 27,85% e 30,65%. Esses resultados são ligeiramente maiores que os reportados na literatura, o que indica que o secador solar desenvolvido na UFCG apresenta um elevado padrão na secagem de banana, além do fácil manuseio, construção e operacionalidade. / This paper presents a comparative study of drying systems for the production of dried bananas. An indirect solar exposure dryer with acquisition system and control of the thermodinamic properties of the drying air, and an automatized electric dryer with embedded control and supervision system were used. The drying systems studied in this paper were: solar drying, electrical drying and mixed drying (solar drying followed by electrical drying). The experimental tests were performed at the UFCG in Campina Grande, PB, for the drying of bananas (Musa spp.). The final product obtained by the three drying systems presented good visual aspect, scent and flavour, and moisture percentage at moist base less than 25%, compatible to the resolution RDC nº 272/05 of the ANVISA. The acquisition system a nd data control, added as inovation at the solar dryer, using the Arduino plataform, granted the measurement of the temperature and air relative moisture of drying air, both in the entrance and exit of the solar colector of the drying chamber, and also the activation and control of the forced convection of the drying system to keep the temperature in the drying chamber between 40ºC and 60ºC. As results, the obtained values to the drying system efficiency are presented, specific comsuption of energy (CEE), drying system efficiency and drying time. Through the experiments with the solar and the electric dryers, the curves that represent the drying kinectics of the banana were obtained. The results were compared and showed that Page’s mathematical model is adequate to predict the drying time. The determination coefficient (R²) obtained at the electric dryer was superior to the solar dryer, this shows that the control system of the thermodinamics properties of the drying air is more efficient on the electric dryer. In relation to the CEE, the electric drying showed a CEE of 379.33 kWh per cycle with a temperature of 45ºC and 225.54 kWh per cycle at the temperature of 55ºC . On the other hand, the mixed drying had a CEE of 295.87 kWh per cycle, at a temperature of 45 ºC, and the solar drying a medium CEE of 45.83 kWh per cycle. This shows the great comparative advantage of the solar dryer when compared to the electric dryer. In relation to the massic efficiency to the 3 drying processes, they showed equivalente massi c efficiency around 89%, which was expected. In relation to the thermic efficiencies of the solar dryer, obtained on the experiments with and without temperature control, were respectively 27.85%, 30.65%, these results show that the obtained resulsts are slightly superior to the results reported on the literature, which indicates that the solar dryer under development in the UFCG shows high efficiency to perform the drying of bananas, although its easy to construct and operate.
18

Species Endemism: Predicting Broad-Scale Patterns and Conservation Priorities

Zuloaga Villamizar, Juan Gerardo January 2018 (has links)
Do thermal barriers limit biotic composition and community similarity, potentially helping to shape biodiversity patterns at continental scales? Are environmental variables responsible for broad-scale patterns of species endemism? Are these patterns predictable? And, how can patterns of endemism can inform global conservation strategies? These are some of the questions that I attempted to answer during my doctoral research. In the first chapter, I tested one of the most contentious hypotheses in ecology: Do thermal barriers, which grow stronger along elevational gradients across tropical mountains, create a dispersal barrier to organisms and consequently contribute to the isolation and divergence of species assemblages? If so, do patterns potentially generated by this mechanism detectably relate to dissimilarity of biotic assemblages along altitudinal gradients across the mountains in the Americas? We found that mountain passes are not only higher in tropical realms, as initially thought by Janzen (1967), and extensively popularized and assumed in further research, but they are also present in temperate regions along the western coast of North America. We also found that the stronger the thermal barrier, the higher the dissimilarity between communities. However, the variance explained was low, suggesting thermal barriers play a minor role in creating and maintaining patterns of biodiversity. The second chapter raises the question of why are there more small-ranged species in some places than in others. I tested four macroecological hypotheses (H1: climate velocity; H2: climate seasonality; H3: climate distinctiveness or rarity; and, H4: spatial heterogeneity in contemporary climate, topography or habitat) to predict broad-scale patterns of species endemism, using a cross-continental validation approach. We found that there is no empirical reason, from the standpoint of model fitting, parameter estimates, and model validation, to claim that any of these hypotheses creates and maintains broad-scale patterns of endemism. Although we found statistically significant relationships, they failed stronger tests of a causal relationship, namely accurate prediction. That is, the hypotheses did not survive the test of cross-continental validation, failing to predict observed patterns of endemism. Climate velocity was dropped from some models, suggesting that early correlations in some places probably reflect collinearity with topography. The effect of richness on endemism was in some cases negligible, suggesting that patterns of endemism are not driven by the same variables as total richness. Despite low explained variance, spatial heterogeneity in potential evapotranspiration was the most consistent predictor in all models. The third chapter is aimed to evaluate the extent to which global protected areas (PAs) have included endemic species (species with small range size relative to the median range size). We measure the relative coverage of endemic species by overlapping species geographic ranges for amphibians, mammals, and birds, with the world database of PAs (1990-2016). Then we measure the rate of expansion of the global PA network and the rate of change in endemic species coverage. We found that ~30% of amphibian, ~6% of bird and ~10% of mammal endemic species are completely outside PAs. Most endemic species’ ranges intersect the PA network (amphibian species = 58%; birds = 83%; mammals = 86%), but it usually covers less than 50% of their geographic range. Almost 50% of species outside the PA network are considered threatened (critically endangered, endangered and vulnerable). We identified that ecoregions in tropical Andes, Mesoamerica, Pacific Islands (e.g., New Guinea, Solomon), Dry Chaco, and Atlantic forests are major conservation priorities areas. The historic rates of new PAs added every year to the network is between ~6,000 to ~15,000. In contrast, we found that rates of including endemic species within the PA network have been fairly slow. Historic data shows that every year, the entire geographic range of 3 (amphibians) to 6 (birds and mammals) endemic species is 100% included inside the PA network (amphibians = from 162 to 233; mammals = 10 to 84; and, amphibians = 16 to 99). Based on these trends, it is very unlikely PAs will include all endemic species (14% total endemic species, that is ~1,508 out of 11,274) currently outside the PA network by 2020. It will require five times the effort made in the last two decades. However, projections also showed that is very likely that some portions of the geographic ranges for all endemic birds and mammals, but not for all endemic amphibians, will be covered by the future PA network. I sum, I found that none of the hypotheses tested here can explain broad-scale patterns of total species richness and total species endemism. My main contribution on this research area is clearly rejecting these hypotheses from potential candidates that may explain biodiversity patterns. By removing them, we advance in this field and open possibilities to test new hypotheses and evaluate their mechanisms. I proposed that other drivers and mechanisms (whether biotic and biotic) acting at local scales, and escaping the detection of macroecological approaches, might be responsible for these patterns. Finally, in terms of conservation planning, I proposed that the international community has an opportunity to protect a great number of endemic species and their habitats before 2020, if they strategically create new PAs.
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Modification de l'écoulement turbulent au sein de passes à poissons à fentes verticales par l'insertion d'obstacles / Modification of the turbulent flow within master keys with fishes with vertical cracks by the insertion of obstacles

Bourtal, Badreddine 06 July 2012 (has links)
L'étude de l'écoulement turbulent au sein des passes à fentes verticales est nécessaire afin d'améliorer ces dispositifs de franchissement contenant des barrières physiques aux mouvements migratoires des poissons. En effet, les études menées sur les passes existantes ont montré leurs limites pour permettre le franchissement des petites espèces de poissons avec des faibles capacités de nage. L'objectif de notre étude est d'adapter l'écoulement turbulent dans la passe aux capacités de nage des poissons. Des mesures de vitesse bidimensionnelle par Vélocimétrie par Imagerie de Particules (PIV) et les mesures de vitesse tridimensionnelle par Vélocimétrie Acoustique par effet Doppler (ADV) ont montré que les grandeurs cinématiques de l'écoulement au sein des passes existantes sont très importantes et donc affectent les capacités de nages des petites espèces de poissons. Une des stratégies pour répondre à ce problème est d'introduire des obstacles de forme cylindrique au sein des bassins de la passe à poissons. L'insertion de ces cylindres a pour objectif de réduire les quantités cinématiques de l'écoulement turbulent au sein de la passe afin d'adapter cet ouvrage au passage des petites espèces de poissons. Cette stratégie nécessite une méthode d'optimisation afin de trouver l'emplacement idéal des cylindres à partir de simulations numériques de l'écoulement (logiciel Star-CD). / The turbulent flow study in vertical slot fishway is necessary to improve this crossing device containing physical barriers to fish migration. Effectively, studies of existing fishways have shown their limits to ensure the crossing of small fish species with weak swimming abilities. The objective of our study is to adapt the turbulent flow to the fish species swimming abilities. The two-dimensional velocity measurements by Particle Image Velocimetry (PIV) and three-dimensional velocity measurements by Doppler Velocimetry Acoustics (ADV) have shown that the flow kinematic quantities within the existing fishways are very important next to the small fish species capacities. One of strategies to answer at this problem is to introduce obstacles with cylindrical shape in the fishways pools. The adjunction of cylinders is intended to reduce the kinematics quantities of the turbulent flow within the fishways in order to adapt this hydraulic structure to the passage of small fish species. This strategy requires an optimization method to find the ideal location of the cylinders from numerical simulations of the flow (Star-CD code).
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Renderingspass och linjärt arbetsflöde i färgrymd

Sahlin, Jimmy January 2012 (has links)
The film industry utilizes more and more computer generated visual effects and the visual effects industry and the surrounding community is continuously growing. It unlocks possibilities for the creative director that before was hard to achieve. And as technology advances, it does not only push the limit of the quality and complexity of the visual effects, but also allows ordinary people and amateurs with a tight budget to create stunning visuals as well.The report will cover render passes and the importance of a linear workflow. The report will determine common key material assets a compositor needs from rendering in order to have full control in post-production. Practical examples made with Maya and Nuke will be used. / <p>Validerat; 20120802 (anonymous)</p>

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