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Articles de revues sur le sujet "Isolats de terrain"
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Mamoudou, A., A. Zoli, C. Tanenbe, J. P. Andrikaye, Mr Bourdanne, Tanguy Marcotty, V. Delespaux, Peter-Henning Clausen et S. Geerts. « Evaluation sur le terrain et sur souris de la résistance des trypanosomes des bovins du plateau de l’Adamaoua au Cameroun à l’acéturate de diminazène et au chlorure d’isométamidium ». Revue d’élevage et de médecine vétérinaire des pays tropicaux 59, no 1-4 (1 janvier 2006) : 11. http://dx.doi.org/10.19182/remvt.9948.
Texte intégralRésumé :
Suite à une enquête dans quelques villages du département de Faro et Déo, le village de Kontcha, qui a présenté la prévalence de la trypanosomose la plus élevée (32,5 p. 100), a été sélectionné afin d’évaluer la résistance des trypanosomes au diminazène et à l’isométamidium. Deux lots de 40 bovins ont été traités au jour 0, l’un au diminazène, l’autre à l’isométamidium. Le statut parasitologique de ces deux lots a été évalué toutes les deux semaines en utilisant la technique du buffy coat pendant une période de deux mois. Chaque animal diagnostiqué positif a été traité au diminazène. Le pourcentage d’animaux infectés par des trypanosomes a été de 32,5 p. 100 dans le lot traité au diminazène et de 27,5 p. 100 dans le lot traité à l’isométamidium. L’analyse de survie ainsi que l’estimation du risque relatif (1,38) ont suggéré une résistance à l’isométamidium et une diminution de l’activité prophylactique de ce produit. Plusieurs animaux traités au diminazène à 7 mg/kg ont été diagnostiqués positifs deux semaines après le traitement, ce qui indiquait également une forte suspicion de résistance à ce trypanocide. Ces résultats du terrain ont été confirmés par le test standardisé sur souris en utilisant six isolats de Trypanosoma congolense provenant des animaux traités. Ces isolats ont été testés au chlorure d’isométamidium (1 mg/kg) et à l’acéturate de diminazène (20 mg/kg) pour établir leur sensibilité. Tous les isolats ont été résistants à au moins un des produits testés, tandis que quatre isolats ont été résistants aux deux produits. Cette étude montre pour la première fois la présence au Cameroun de souches de trypanosomes résistantes aux trypanocides.
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Oyekunle, M. A., et A. I. Adetosoye. « Tests de sensibilité antimicrobienne in vitro de Nocardia isolée sur le terrain chez des animaux affectés d’une dermatose ». Revue d’élevage et de médecine vétérinaire des pays tropicaux 54, no 3-4 (1 mars 2001) : 197. http://dx.doi.org/10.19182/remvt.9772.
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Des tests antimicrobiens in vitro ont été effectués sur des souches de Nocardia isolée sur le terrain dans des cas de nocardiose chez des animaux d’élevage. Les résultats obtenus par la méthode des disques ont monté la nature multirésistante des isolats, bien que 23,81 et 21,43 p. 100 d’entre eux aient été sensibles respectivement à la ciprofloxacine et à la gentamicine. Les valeurs des concentrations minimales inhibitrices et leurs étendues ont été respectivement de 12,5 et 3,12–25 μg/ml pour l’oxytétracycline, et de 3,12 et 0,78–6,25 μg/ml pour l’érythromycine.
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SARRADIN, P., et H. LAUDE. « Diversité des souches d’Encéphalopathie Spongiforme Transmissible chez les ruminants : enjeux, bilan et perspectives ». INRAE Productions Animales 17, HS (19 décembre 2004) : 13–20. http://dx.doi.org/10.20870/productions-animales.2004.17.hs.3617.
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Les Encéphalopathies Spongiformes Transmissibles (EST) ou maladies à prion se caractérisent par l’accumulation dans le tissu nerveux d’une forme anormalement repliée d’une protéine cellulaire de l’hôte, la PrPc. Cette isoforme anormale, ou PrPsc, supposée responsable des désordres neurodégénératifs observés, est aussi assimilée par de nombreux auteurs à l’agent transmissible lui-même, lequel serait alors dépourvu de génome et se propagerait de manière épigénétique. Un phénomène au coeur des recherches sur les EST est l’existence de variants phénotypiques, ou souches. Les souches de prions peuvent être différenciées entre elles sur une base biologique, par la nature des manifestations anatomo-pathologiques engendrées lors de leur propagation chez un même hôte, en particulier une lignée pure de souris, et sur une base biochimique, par le profil moléculaire de la PrPsc présente dans le cerveau des individus atteints. Le déterminisme biologique et moléculaire de cette diversité et la dynamique évolutive qu’elle suggère demeurent largement incompris. De ce fait, la caractérisation des souches qui infectent les espèces naturellement atteintes par les EST constitue une tâche relativement ardue, au demeurant essentielle à la compréhension de l’épidémiologie de ces maladies, à leur contrôle sur le terrain et à la protection de la santé humaine. Les recherches menées à l’INRA visent à documenter la diversité des souches d’EST chez les petits ruminants par typage des isolats de tremblante naturelle, et à mieux comprendre le déterminisme de cette diversité. Elles ont également pour objectif l’amélioration des méthodes actuelles de typage en termes de rapidité et de fiabilité, notamment à travers le développement de souris transgéniques plus réceptives à la transmission que les souris conventionnelles.
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Abolude, Akintayo, et Wen Zhou. « A Comparative Computational Fluid Dynamic Study on the Effects of Terrain Type on Hub-Height Wind Aerodynamic Properties ». Energies 12, no 1 (28 décembre 2018) : 83. http://dx.doi.org/10.3390/en12010083.
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The increased adoption of wind power has generated global discourse in wind energy meteorology. Studies based on turbine performances show a deviation of actual output from power curve output, thereby yielding errors irrespective of the turbine site. Understanding the cause of these errors is essential for wind power optimization, thus necessitating investigation into site-specific effects on turbine performance and operation. Therefore, Computational Fluid Dynamics simulations of hub-height wind aerodynamic properties were conducted based on the k-ε turbulence closure model Reynolds Averaged Navier Stokes equations for three terrains. To isolate terrain-induced effects, the same 40 m above mean sea level wind climatology was imposed on all three terrains. For the four wind directions considered, turbulence intensity (TI) was least in the offshore terrain at about 5–7% but ranged considerably higher from 4–18% for the coastal and island terrain. TI on crests also increased significantly by up to 15% upstream of wind direction for the latter terrains. Inflow angle ranged from −15° to +15° in both coastal and island terrains but remained at <+1° in the offshore terrain. Hellman exponent increased from between factors of 2–4 in the other two terrains relative to that of the offshore terrain. Wind speed-up varied from about 1.06–1.13, accounting for a range of 17–30% difference in power output from a hypothetical operational 2 MW turbine output placed in the three different terrains. Turbine loading, fatigue, efficiency, and life cycle can also be impacted by the variations noted. While adopting a site-specific power curve may help minimize errors and losses, collecting these aerodynamic data alongside wind speed and direction is the future for wind power optimization under big data and machine learning.
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Asfour, Hani Z., Zuhier A. Awan, Alaa A. Bagalagel, Mahmoud A. Elfaky, Reda F. A. Abdelhameed et Sameh S. Elhady. « Large-Scale Production of Bioactive Terrein by Aspergillus terreus Strain S020 Isolated from the Saudi Coast of the Red Sea ». Biomolecules 9, no 9 (12 septembre 2019) : 480. http://dx.doi.org/10.3390/biom9090480.
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The diversity of symbiotic fungi derived from two marine sponges and sediment collected off Obhur, Jeddah (Saudi Arabia), was investigated in the current study. A total of 23 isolates were purified using a culture-dependent approach. Using the morphological properties combined with internal transcribed spacer-rDNA (ITS-rDNA) sequences, 23 fungal strains (in the majority Penicillium and Aspergillus) were identified from these samples. The biological screening (cytotoxic and antimicrobial activities) of small-scale cultures of these fungi yielded several target fungal strains which produced bioactive secondary metabolites. Amongst these isolates, the crude extract of Aspergillus terreus strain S020, which was cultured in fermentation static broth, 21 L, for 40 days at room temperature on potato dextrose broth, displayed strong antimicrobial activities against Pseudomonas aeruginosa and Staphylococcus aureus and significant antiproliferative effects on human carcinoma cells. Chromatographic separation of the crude extract by silica gel column chromatography indicated that the S020 isolate could produce a series of chemical compounds. Among these, pure crystalline terrein was separated with a high yield of 537.26 ± 23.42 g/kg extract, which represents the highest fermentation production of terrein to date. Its chemical structure was elucidated on the basis of high-resolution electrospray ionization mass spectrometry (HRESIMS) or high-resolution mass spectrometry (HRMS), 1D, and 2D NMR spectroscopic analyses and by comparison with reported data. The compound showed strong cytotoxic activity against colorectal carcinoma cells (HCT-116) and hepatocellular carcinoma cells (HepG2), with IC50 values of 12.13 and 22.53 µM, respectively. Our study highlights the potential of A. terreus strain S020 for the industrial production of bioactive terrein on a large scale and the importance of future investigations of these strains to identify the bioactive leads in these fungal extracts.
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Grauch, V. J. S. « A new variable‐magnetization terrain correction method for aeromagnetic data ». GEOPHYSICS 52, no 1 (janvier 1987) : 94–107. http://dx.doi.org/10.1190/1.1442244.
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Terrain effects in aeromagnetic data are produced by rugged, magnetic topography. These effects mimic the shape of topography and can often be so large that they obscure anomalies of interest. Thus it is desirable to remove terrain effects from aeromagnetic data in order to isolate the anomalies to be investigated. However, removal of aeromagnetic terrain effects has been a longstanding problem. Previously developed methods have succeeded only in certain, specific geologic situations. I present a new aeromagnetic terrain‐correction method that is superior to the previously developed methods for the general case. This method takes into account the highly variable magnetic properties of rocks and can remove terrain effects whether the sources of interest are shallow or deep. The new method is based on the assumption that magnetic sources of interest are often geometrically unrelated to terrain. It finds the magnetization that gives a magnetic‐field residual with minimum correlation to terrain effects for a window of data within a grid of magnetic‐field values. By repeating the calculation for windows covering the entire grid, a grid of variable‐magnetization values is produced which is combined with topography to calculate a magnetic‐terrain correction. The variable‐magnetizaton method was extensively tested using theoretical models (where the answer is known) and using real data from the Lake City caldera area in the San Juan Mountains of southern Colorado. The tests demonstrated the method’s effectiveness in removing terrain effects from aeromagnetic data. Valid terrain corrections were not obtained where anomalies of interest correlated with terrain effects. However, these places are readily recognizable and easily corrected by editing some of the magnetization values.
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Taoufik, Lahoucine, Asma Amrani Hanchi, Bennaoui Fatiha, Slitine Nissrine, Maouainine Fadl Mrabih Rabou et Soraa Nabila. « Emergence of OXA-48 Carbapenemase Producing Klebsiella pneumoniae in a Neonatal Intensive Care Unit in Marrakech, Morocco ». Clinical Medicine Insights : Pediatrics 13 (janvier 2019) : 117955651983452. http://dx.doi.org/10.1177/1179556519834524.
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Goal: This work aims to describe and explore the circumstances of appearance of Klebsiella pneumoniae producing OXA-48 carbapenemase, which has occurred in a neonatal intensive care service at the Mohammed VI University Hospital of Marrakech. Results: During February 2015, the alert was triggered by the isolation of 6 isolates of K pneumoniae with the same antibiotic susceptibility profile in the neonatal intensive care service, suggesting a possible outbreak. Blood cultures represented the main site of isolation of these isolates. The phenotypic study of the isolates made it possible to identify a strain of K pneumoniae susceptible to third-generation cephalosporins, ciprofloxacin, and aminoglycosides, and resistant to ertapenem, β-lactamases inhibitors (ticarcillin-clavulanate, piperacillin-tazobactam; amoxicillin-clavulanic acid), and cotrimoxazole. The genotypic study of the epidemic isolate revealed the presence of the blaOXA-48 gene. The action to be taken was the establishment of corrective measures to stop this epidemic to a multi-resistant germ transmitted by hand transmission. The reinforcement of hygiene measures and the awareness of the staff made it possible to put an end to the epidemic at March 30, 2015, without closing the service. The outcome of 6 infected newborns was fatal due to the fragile terrain and the inappropriate probabilistic antibiotic therapy. Conclusion: The production of carbapenemase in K pneumoniae is an emerging resistance mechanism that must be suspected and identified to offer targeted therapy and to limit its spread. The implementation of a local policy to control multidrug-resistant germs is essential to limit their dissemination in hospitals.
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Radišić, Tomislav, Doris Novak et Tino Bucak. « The Effect of Terrain Mask on RAIM Availability ». Journal of Navigation 63, no 1 (1 décembre 2009) : 105–17. http://dx.doi.org/10.1017/s0373463309990294.
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Receiver Autonomous Integrity Monitoring (RAIM) is a method, used by an aircraft's receiver, for detecting and isolating faulty satellites of the Global Navigation Satellite System (GNSS). In order for a receiver to be able to detect and isolate a faulty satellite using a RAIM algorithm, a couple of conditions must be met: a minimum number of satellites, and an adequate satellite geometry. Due to the highly predictable orbits of the GPS satellites, a RAIM availability prediction can be done easily. A number of RAIM methods exist; however, none of them takes into account the precise terrain masking of the satellites for the specific location. They consider a uniform fixed mask angle over the whole horizon. This paper will introduce the variable mask RAIM algorithm in order to show to what extent the terrain can affect the RAIM availability and how much it differs from the conventional algorithms.
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Parish, Thomas R., et Bart Geerts. « Airborne Measurements of Terrain-Induced Pressure Perturbations ». Monthly Weather Review 141, no 11 (25 octobre 2013) : 3814–26. http://dx.doi.org/10.1175/mwr-d-13-00044.1.
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Abstract Airborne measurement of the horizontal pressure field using differential GPS technology has been established during the last few years. Accurate aircraft measurement of the horizontal pressure gradient force requires an independent determination of the height of the airborne platform above some reference level. Here the authors demonstrate a differential GPS technique that uses data from a fixed reference station to refine the vertical position of the aircraft. A series of research flight legs by the University of Wyoming King Air research aircraft (UWKA) were conducted during the winter seasons of 2008 and 2009 over the Medicine Bow Mountains in southern Wyoming. Flight patterns consisted of a series of geographically fixed, parallel legs along a quasi-isobaric surface above the mountainous terrain, allowing the finescale mapping of the horizontal pressure (or geopotential height) field. The removal of the large-scale gradient and tendency isolates the terrain-induced pressure perturbation field. Results obtained using differential GPS measurements of aircraft height show that the Medicine Bow Range induces pronounced horizontal pressure perturbations, with a leeside region of low pressure downwind of the crest, in two cases: on 11 February 2008 and 20 February 2009. A wind maximum is found downwind of the elevated terrain consistent with this pressure gradient. Simulations of these two cases were performed using the Weather Research and Forecasting Model (WRF). The WRF height patterns for the time of the UWKA flight matched the general isobaric height patterns observed. Simulations and observations consistently show that the cross-mountain acceleration is stronger when the perturbation pressure gradient is larger.
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Dawood, Hayder Hasan. « The Use of Some Animal Wastes in the Control of the Pathogenic Fungi Fusarium Solani And Rhizoctonia Solani on Tomato Plants ». JOURNAL OF UNIVERSITY OF BABYLON for Pure and Applied Sciences 31, no 2 (29 juin 2023) : 55–63. http://dx.doi.org/10.29196/jubpas.v31i2.4655.
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Background: This study was conducted to evaluate the efficiency of animal waste in controlling seedling death and root rot diseases in tomato caused by the pathogenic fungi Fusarium solani and Rhizoctonia solani In open field conditions, which were isolated from the soil of different locations. singly or in combination with the bio-control fungus Trichoderma harzianum.
Materials and Methods: The fungal pathogens and fungi, Fusarium solani and Rhizoctonia solani, were tested and diagnosed, and the pathogenicity of the fungal isolates was tested. The resistance preparation was introduced, and the terrain ability was tested for it
Results:The results of the pathogenicity test showed that the isolates taken from the greenhouses / Hilla R. solani and F. solani had the highest percentage of seedling mortality after emergence, reaching 97.500 and 95.00, respectively.The interaction showed the antagonistic ability of the fungus Trichoderma harzianum against the pathogenic fungi R. solani and F. solani, achieving an antibody score of 2.25
Conclusion: The results of the aqueous extract of animal waste showed a significant reduction of the two pathogens R.solani and F.solani, where it reached the highest value at 4.100 when isolate F.solani for poultry extract and the smallest value was 8.300 when extracting cows, while all aqueous extracts did not affect the growth of the biofungus T. harzianum .It amounted to 8,900, 9,000, 8,925, and 8,925 (cows, sheep, horses, and poultry), respectively. The results of the laboratory isolation of animal waste showed the presence of (6) species of fungi.. Alternaria sp, Aspergillus niger, Penicillium sp, Trichoderma harzianum , macrohpomina sp , Cylindrocarpon sp
Thèses sur le sujet "Isolats de terrain"
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Siau, Anthony. « Biopuces à ADN pan-génomique de Plasmodium falciparum : mise au point d'une technique de marquage par radio-isotope adaptée aux petits échantillons biologiques et application à l'étude de la pathogénocité du parasite ». Paris 6, 2008. http://www.theses.fr/2008PA066092.
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L’exploration de l’ensemble du transcriptome de P. Falciparum est désormais accessible grâce à la technique des biopuces à ADN sur lame de verre (microarray). Mais cette technologie puissante reste cependant limitée à l’étude d’échantillons biologiques dont les quantités d’ARN totaux sont importantes. Bien que de nombreuses méthodes aient été développées afin d’adapter ces techniques aux faibles quantités d’ARN total, nous avons choisi d��utiliser une approche par biopuce à ADN hybridé à des sondes marquées avec des radio-isotopes, réputée très sensible. En comparant le transcriptome d’isolats de terrain de P. Falciparum susceptibles d’induire ou non in vitro l’apoptose des cellules endothéliales, nous avons pu identifier des gènes préférentiellement surexprimés dans les isolats apoptogènes. Par ailleurs, la technologie des biopuces radioactives a été aussi utilisée pour étudier les premières phases du développement des sporozoïtes de P. Falciparum dans son hôte. Nous avons ainsi pu identifier de nombreux gènes potentiellement impliqués dans l’infection hépatique.
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Bastos, Francisco Albuquerque. « OTIMIZAÇÃO DO PROCESSO DE PRODUÇÃO DE TIQUIRA EMPREGANDO ENZIMAS COMERCIAIS E FUNGOS ISOLADOS A PARTIR DOS BEIJUS UTILIZADOS NO MÉTODO TRADICIONAL ». Universidade Federal do Maranhão, 2013. http://tedebc.ufma.br:8080/jspui/handle/tede/955.
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Previous issue date: 2013-12-20Tiquira, a strong content beverage from Maranhão ( Brazil ), obtained from cassava (Manihot esculenta Crantz.) has its production concentrated in several counties of the State, through a handmade process , rather primitive, in which the conversion of starch cassava is taken into fermentable sugars by fungi which is found on the native beijus of manioc where strains are picked at random. Alcoholic fermentation is also made by yeasts found in the environment. Its commercialization is practiced informally, making it difficult to record statistical data of production and the number of producers in the Ministry of Agriculture. In order to optimize this process, commercial enzymes, strains of fungi (Aspergillus niger), were used to in order to convert starch into fermentable wort and pressed yeasts for fermentation. The processes proposed here follow three steps: gelation of starch scarification and subsequent dextrinization the sugars, alcoholic fermentation and distillation of fermented wine. Substituting the mold for commercial enzymes in the proposed circumstances, the manufacturing of tiquira was performed in just 25 hours, whereas when using fungi isolated, the production of tiquira took approximately 136 hours for its processing. As one can see, there was a considerable reduction of time in the two cases presented here in relation to the traditional process, which takes approximately 20 days to achieve the distillate. It was also found that the fermentation and destillation of the wort resulting from the scarification of cassava is equivalent to that of cane sugar, and both processes can be processed with the same equipment by tiquira producers. It was shown that the concentrations of copper and ethyl carbamate were visibly reduced in comparison to the traditional process, enabling a better quality of the beverage, as well as reducing the risks to consumer health. From the experiments it can be concluded that the replacement of the traditional process by commercial enzymes, fungi isolated and pressed yeast are highly and technically recommended primarily to small producers.
A tiquira é uma bebida típica do Maranhão (Brasil), obtida a partir de mandioca (Manihot esculenta, Crantz.), sua produção se concentra em diversos municípios do Estado, através de um processo artesanal, bastante primitivo, no qual a conversão do amido de mandioca em açúcares fermentescíveis é feita por bolores nativos que surgem sobre os beijus de massa de mandioca, onde as cepas são colhidas ao acaso. A fermentação alcoólica também é feita por leveduras selvagens. Tem sua comercialização praticada de modo informal, dificultando o registro de dados estatísticos de produção e número de produtor no Ministério da Agricultura. Com o objetivo de otimizar o referido processo, utilizaram-se, enzimas comerciais, cepas de fungos (Aspergillus níger), para a conversão do amido em mosto fermentescíveis e leveduras prensadas para fermentação. Os processos aqui propostos seguiram três etapas: gelificação do amido com a posterior dextrinização e sacarificação a açúcares, fermentação alcoólica e destilação do vinho fermentado. Substituindo-se os bolores por enzimas comerciais nas circunstâncias propostas, a fabricação da tiquira foi realizada em apenas 25 horas, enquanto que ao utilizar fungos isolados, a produção do aguardente demorou, aproximadamente, 136 horas para o seu processamento. Evidenciou-se assim, uma considerável redução de tempo, nos dois processos aqui apresentados em relação ao processo tradicional, que demora, aproximadamente, 20 dias para a consecução do destilado. Verificou-se também que os processos de fermentação e destilação do mosto oriundos da sacarificação da massa de mandioca são equivalentes ao da cana-de-açúcar, podendo ser processados com os mesmos equipamentos, por pequenos produtores de tiquira. Comprovou-se que as concentrações de cobre e carbamato de etila foram visivelmente reduzidas nos processos propostos em relação ao processo tradicional, possibilitando uma melhor qualidade da bebida, assim como reduzindo os riscos à saúde dos consumidores. A partir dos experimentos realizados conclui-se que a substituição do processo tradicional por enzimas comerciais, fungos isolados e levedura prensada se mostra tecnicamente possível e recomendada, primordialmente, aos pequenos produtores.
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Escote, Marcia Tsuyama. « Estudo da transição metal-isolante em óxidos de terra-rara e níquel ». Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-11122013-170810/.
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Esta tese apresenta um estudo sistemático da síntese e das propriedades físicas de amostras policristalinas de Nd IND. 1-X R IND. X NiO IND. 3; R = Sm, Eu, 0 < OU = X < OU = 1. Estes materiais apresentam uma transição de fase metal-isolante MI em temperaturas 200 < OU = T IND. MI < OU = 400 K. Amostras foram produzidas a partir do método de precursores sol-gel, sinterizadas a 1000 GRAUSC e sob pressões de O IND. 2 de até 80 bar. O estudo da influência da substituição de R POT. 3+ na matriz de NdNiO IND. 3 foi realizado a partir das caracterizações através de medidas de difração de raios-X DRX, difração de neutrons como função da temperatura DRN, transporte elétrico ro(T), transporte térmico capa(T), coeficiente Seebeck S(T), calorimetria diferencial e susceptibilidade magnética qui(T). Os resultados de DRX revelaram que as amostras são monofásicas e cristalizam-se na estrutura perivskita distorcida ortorrombicamente, grupo espacial Pbnm. As medidas de DRN realizadas nas amostras de Nd IND. 1-XEu IND. X NiO IND. 3 mostraram a evolução dos parâmetros de rede e do volume da cela unitária V como função da temperatura. Estas caracterizações revelaram que, em T DA ORDEM DE T IND. MI, ocorre uma expansão em V, assim como um aumento do ângulo de ligação Ni-O e uma diminuição do ângulo de \"superexchange\" teta. Medidas de ro(T) revelam a ocorrência da transição MI em um amplo intervalo de temperatura 200 < OU = T IND. MI 400 K. Através destas medidas verificou-se também a presença de histerese térmica ocorre decresce continuamente com o aumento de x, até anular-se em x > 0,5 e em x > 0,35 para R=Sm e Eu, respectivamente. Este resultado foi confirmado através das medidas de capa(T) e S(T). Além disso, verificou-se a importância da contribuição da rede na capa(T). As medidas de S(T) indicam que os portadores de carga são elétrons e que a densidade de ) estados no nível de Fermi N(E IND. F) foi estimada ser da ordem de 10 POT. 23 (eVcm POT. 3) POT. -1. Os valores de T IND. MI e a presença ou não de histerese térmica foram verificados através das medidas de DSC. Um estudo foi feito para verificar qual a maneira mais precisa de subtrair a contribuição dos íons terras-raras nas medidas de susceptibilidade magnética qui(T) dos compostos Nd IND. 1-X R IND. X NiO IND. 3. Após estas correções foi possível verificar o ordenamento magnético da sub-rede do Ni POT. 3+ na região de temperatura T IND. n DA ORDEM DE 200 K para as amostras com x < 0,4 e x < 0,25 para R=Sm e Eu, respectivamente. Ajustes lineares feitos em qui(T) acima de temperaturas T > 200 K revelaram valores de momentos magnéticos efetivos müeff variando de 1,7 a 1,8 mü IND. B o que está em concordância com o valor esperado de müeff DA ORDEM DE 1,76 mü IND. B do íon livre de Ni POT. 3+. Adicionalmente, uma separação precisa do termo independente da susceptibilidade magnética foi efetuada e a susceptibilidade de Pauli dos materiais foi encontrada. Foi possível então obter uma estimativa da densidade de estados no nível de Fermi N(E IND. F), que gerou valores similares aos obtidos via medidas do coeficiente Seebeck. Entretanto, o comportamento de qui(T) corrigido abaixo de T IND. n revelou características de um antiferromagnetismo não convencional devido a um aumento monotônico de qui(T) com o decréscimo da temperatura e a presença de irreversibilidade nas curvas resfriadas a campo magnético zero ZFC e do refinamento de estrutura estimou-se que a valência no Ni nas amostras de Nd IND. 1-X R IND. X NiO IND. 3 DA ORDEM DE 3. Estimativas grosseiras da largura de bando W do O 2ro e da energia de transferência de carga delta para a série de compostos Nd IND. 1-X R IND. X NiO IND. 3 revelaram valores compatíveis com aqueles ) encontrados na literatura. De maneira geral, as caracterizações das propriedades estruturais, de transporte e magnéticas sugerem que os compostos Nd IND. 1-X R IND. X NiO IND. 3 podem ser classificados como sistemas onde correlações eletrônicas e flutuações dessas correlações ocorrem. Foram discutidas algumas limitações acerca da aplicabilidade dos modelos vigentes para a explicação da transição metal-isolante nos niquelatos aqui estudados.This work reports a systematic study on the synthesis and general physical properties of polycrystalline samples of Nd IND. 1-X R IND. X NiO IND. 3; R = Sm, Eu, 0 < OU = X < OU = 1. These compounds exhibit a metal-insulator MI phase transition in a broad range of temperature 200 < OU = T IND. MI < OU = 400 K. The samples were prepared through sol-gel precursors and sintered at extreme conditions: high temperatures 1000 GRAUSC and under oxygen pressures up to 80 bar. These samples were characterized by several techniques including X-ray powder diffraction XRD, neutron diffraction as a function of temperature NRD, electrical resistivity ro(T), thermal conductivity capa(T), Seebeck coefficient S(T), differential scanning calorimetry DSC, and magnetic susceptibility qui(T). The results of XRD revealed that all samples are single phase and crystallize in an orthorhombic structure, space group Pbnm. The NRD data, combined with the Rietveld analysis, indicated small changes in the lattice parameters a, b, and c and in the volume V of the unit cell T DA ORDEM DE T IND. MI. Such a small change in these parameters is accompained by either a little decrease of the superexchange angle teta and a small expansion of the Ni-O bond-length. The ro(T) data exhibit interesting features such as: (1) a metallic-like behavior of ro(T) at high temperatures; (2) a huge increase of the magnitude of ro(T) at T DA ORDEM DE T IND. MI; and (3) a thermal hysteresis occurring just below T DA ORDEM DE T IND. MI in a temperature interval as large as 100K. Such a thermal hysteresis is characteristic of a first order MI transition and was found to vanish with increasing substitution of x. This strongly suggests that increasing x modify the character of this transition to second order. Thermal properties were carried out and confirmed the change of this MI transition with increasing x. In addition, an analysis of the capa(T) data indicate that phonons are the major thermal carriers in these nickelates. Also, the Seebeck coefficient S(T) data revealed features of a conventional metal at higher temperatures with electrons as carriers. An accurate analysis of the S(T) data based on simple band structure arguments indicate a density of states at the Fermi level of 10 POT. 23 (eVcm POT. 3) POT. -1 and energy gaps in the insulating regime close to 20 meV. The character of the first order transition in lightly substituted samples at T DA ORDEM DE T IND. MI was also inferred from the DSC data. The S(T) data confirmed the occurrence of the metal-insulator transition and the already observed change from first to second order character with increasing x. The magnetic susceptibility ípsilon(T) data have been precisely corrected by a systematic subtraction of the R POT.3+-ion contribution of the measured qui(T). Linear adjusts of the corrected curves above 150K where found to fit the Curie-Weiss law with effective magnetic moment of mü IND. EFF ~ 1.76 mü IND. B, which is close to the free-ion value of mü IND. EFF ~ 1.76 mü IND. B (Ni POT. 3+). These results indicate that the Ni POT. 3+ array displays an antiferromagnetic ordering below a well-defined temperature T IND. N, which is close to T IND.MI for Nd IND. 1-X R IND. X NiO IND. 3 and lightly substituted samples. However, the evolution of the susceptibility of the Ni POT. 3+ array displays features which are fingerprints of unconventional antiferromagnetic state. These features, observed mostly below T IND. N, include a field independent irreversibility of qui(T) and a systematic increase of qui(T) with decreasing temperature, resembling that of a paramagnet. An analysis of the electronic contribution to ípsilon(T) resulted in a density of states at the Fermi level close to the one estimated from the S(T) data. These results are discussed within the context of recent experimental results and theories employed to explain the origin of the metal-insulator transition in these nickelates.
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Lima, Raul Gomes Taveira de. « Estudo da viabilidade do EPS em sistemas de cobertura invertida ». Master's thesis, Departamento de Engenharia Civil, 2000. http://hdl.handle.net/10316/15778.
Texte intégral
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Souza, Jean Carlo 1993. « Estudos de ressonância de spin eletrônico (RSE) em isolantes topológicos dopados com terras-rara ». [s.n.], 2017. http://repositorio.unicamp.br/jspui/handle/REPOSIP/326704.
Texte intégralRésumé :
Orientador: Pascoal José Giglio PagliusoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
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Resumo: A ideia de topologia na Física da Matéria da Condensada, apesar de ter surgido com o efeito Hall quântico inteiro, só voltou a ser explorada recentemente na busca de novas fases da matéria depois do surgimento dos Isolantes Topológicos (ITs) 2D. Após a previsão teórica, e a descoberta experimental, foi proposto que esta nova fase poderia ser generalizada para sistemas 3D, em que o volume do material seria isolante com estados metálicos de superfície que possuiriam canais de spin polarizados. Apesar de diversos experimentos e o surgimento de outras fases topológicas da matéria subsequentes, ainda há dúvidas sobre a natureza dos ITs 3D. Os efeitos topológicos mais claros ainda não foram observados de forma inequívoca e reprodutível experimentalmente e ainda seria de extrema valia encontrar técnicas experimentais que possam complementar os mais discutidos experimentos de ARPES. Nesta dissertação foram estudadas duas famílias distintas de materiais propostas como possíveis ITs 3D: os binários Bi2Se3 e Sb2Te3 e o half-Heusler YPdBi. Utilizando a técnica de auto-fluxo e a fusão estequiométrica, os sistemas foram sintetizados dopados com os terras-rara Gd3+, Nd3+ e Er3+ para realizar estudos de ressonância de spin eletrônico (RSE) e do papel dos efeitos de campo cristalino (CEF) - no caso do half-Heusler. Para o ternário YPdBi foram feitos dois estudos. Na família dos half-Heuslers, a ordem topológica surge da relação entre o acoplamento spin-órbita e a hibridização, que está ligada com a mudança do parâmetro de rede, então os efeitos de CEF poderiam estar refletindo a transição entre a trivialidade e a não-trivialidade. A partir das medidas de susceptibilidade magnética em função da temperatura das amostras dopadas com Nd3+ e Er3+ combinadas com os estudos de RSE, foi possível extrair os parâmetros de campo cristalino (CFP) de quarta e sexta ordem. Comparando esses dados com resultados anteriores para o material, supostamente, não-trivial YPtBi, observou-se uma mudança sistemática no sinal dos CFP. Resultados prévios para as amostras de YPtBi dopadas com Nd3+ mostram uma evolução não usual para uma forma de linha difusiva com a potência de micro-onda. Neste trabalho também foi realizado um estudo da forma de linha em função da potência. Apenas a ressonância do Nd3+ para os monocristais de 10% de Nd em YPdBi mostrou uma forma de linha difusiva que evolui com a potência da micro-onda. No caso dos binários Bi2Se3 e Sb2Te3, o objetivo era otimizar a rampa de tratamento térmico para obter monocristais melhores que poderiam permitir a observação de um espectro totalmente resolvido do Gd3+. Após mudanças no crescimento dos monocristais, o espectro totalmente resolvido foi obtido para as amostras de Bi2Se3. No caso do Sb2Te3 apenas uma linha central com a estrutura fina colapsada foi observada. Acompanhando o deslocamento g e a evolução da largura de linha dH da RSE do Gd3+ com a temperatura, o comportamento negativo do deslocamento g para toda a faixa de temperatura indica que elétrons do tipo p são os grandes responsáveis pela formação da superfície de Fermi residual destes sistemas. Um aumento no coeficiente angular de dH em função da temperatura, a taxa Korringa b, foi observado em baixas temperaturas, logo diferentes concentrações de Gd3+ foram utilizadas para estudar este comportamento. Novamente observou-se um comportamento anômalo em baixas temperaturas, o que poderia estar relacionado com a evolução dos CFP com a temperatura. Todos esses resultados foram discutidos levando-se em conta a possibilidade de existência de topologia não-trivial na estrutura eletrônica desses materiais, com foco particular na relação da interação spin-órbita e os efeitos de campo cristalino com a manifestação da topologia não trivial nesses sistemas
Abstract: The idea of topological systems in Condensed Matter Physics, although already explored in the Quantum Hall Effect, has recently become a topic of intense scientific investigation. In particular, great efforts have been dedicated to the search for new quantum phases since the proposal of the Topological Insulators (TIs) in 2D. After the theoretical prediction and the experimental discovery of the TIs in the 2D case, the existence of the Quantum Hall Spin Effect in 3D, 3D TIs, was proposed, where an insulator bulk and metallic surface states with spin polarized channels could be experimentally realized. Although many experiments have been performed, and some groups claimed the direct observation of such new topological phases, there is still a lot of controversy about the nature of the 3D TIs and about the actual microscopic origin of the metallic states on the surface of the studied materials. Other signatures of the topological phases have not been unambiguously and repeatedly measured yet and there is an obvious lack of a supplementary lab technique to be compared to the most used technique to probe these states, which is ARPES. In this work we have studied two different classes of 3D TIs: the binaries Bi2Se3 and Sb2Te3 and the half-Heusler YPdBi. We have been able to grow single crystals of these materials pure and rare-earth doped with Gd3+, Nd3+ and Er3+ using the self-flux technique and the stoichiometric melting. The aim was to use these crystals to study Electron Spin Resonance (ESR) as a potential probe to investigate the existence of the metallic surface states and to explore the possible of the crystalline electrical field (CEF) effects on the formation of the non-trivial electronic structure of these materials. Regarding the YPdBi, our ESR and magnetization studies have revealed that, in the half-Heusler family, the topological order emerges from the interplay between spin-orbit coupling and the hybridization, which is connected with the changes on the lattice parameter. Thus, the CEF effects could reflect the transition from trivial to nontrivial topology. From the magnetic susceptibility data as a function of temperature from the Nd3+ and Er3+ doped samples combined with the ESR studies, it was possible to extract the fourth and sixth order crystal field parameters (CFP). Comparing our data with the previous results from YPtBi, which is a putative non-trivial material, a systematic change in the sign of the CFP was observed. Previous results with the YPtBi Nd-doped samples show an unusual evolution of the Nd3+ ESR line to a diusive-like line shape as a function of the microwave power. In this work we have performed a similar study of the Nd3+ ESR line shape as a function of the microwave power. Only for the single crystal of 10% Nd in YPdBi resonance shows a diffusive-like line shape that evolves with the microwave power. In the case of the binaries Bi2Se3 e Sb2Te3, the aim of this work was to optimize the heat treatment used in previous works of our group to obtain better single crystals that could allow the observation of the full resolved spectra from Gd3+. After many changes in the single crystal growth method, we were able to observe fully resolved Gd3+ ESR spectra in the Bi2Se3 samples. Regarding the Sb2Te3 single crystals, only a single Gd3+ Dysonian ESR line was observed. Following the Gd3+ ESR dg and dH as a function of temperature, the observed negative behavior of dg, in the whole temperature range studied, indicates that p-type electrons are the main source for the formation of the small the Fermi surface of these materials. An increase of the angular coefficient of dH as a function of temperature, the Korringa rate b, at low temperatures was observed and different concentrations of Gd3+ were required to investigate this anomaly. Again this anomalous behavior at low temperatures was observed for the all Gd-doped samples, which could be related to an evolution of CFP with temperature. We discuss our results taking into account the existence of non-trivial topological states in our samples and the role of spin-orbit and CEF effects might have in the formation of such states
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Silva, Neto Gustavo Cunha da. « Um método para solução de problemas de otimização multiobjetivo em ambiente fuzzy ». Universidade Federal do Amazonas, 2011. http://tede.ufam.edu.br/handle/tede/3689.
Texte intégralRésumé :
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This paper presents a model for solving multiobjective linear programming problems based on the calculation of the minimum fuzzy distance. The theoretical principles outline some elements of the fuzzy logic as well as crisp multiobjective optimization elements needed for the formulation of the model. Moreover, some classical multiobjective methods are presented and classified in three types: a priori, a posteriori and interactive. From these elements we formulate the method for finding an efficient solution from the minimal fuzzy distance, obtained through a subproblem which is calculated based on the L1 metric. At the end, a study case is done in the context of energy planning in isolated electric systems in which we analyze the inclusion of biodiesel as input for electricity generation taking into account the values of the overall cost for generation and number of direct jobs promoted using this technology. In addition, we evaluate, from the values obtained, the environmental impact represented here by the emission of carbon dioxide with the use of their inputs.
Neste trabalho apresenta-se um modelo para solução de problemas de programação linear multiobjetivo baseado no cálculo da distância mínima fuzzy. Os fundamentos teóricos discorrem sobre alguns elementos de lógica fuzzy bem como elementos de otimização multiobjetivo crisp necessários para formulação do modelo. Além disso, apresentam-se alguns métodos multiobjetivo clássicos que são classificados em três tipos: à Priori, à Posteriori e Interativos. A partir destes elementos, formula-se o método para encontrar uma solução eficiente a partir da distância mínima fuzzy, obtida através de um subproblema calculado com base na métrica L1. Ao final, faz-se um estudo de caso no contexto do planejamento energético de sistemas elétricos isolados sobre o qual se analisa a inclusão do biodiesel como insumo para geração de energia elétrica levando em consideração os valores do custo global para geração e número de empregos diretos promovidos com a utilização dessa tecnologia. Além disso, avalia-se, a partir dos valores obtidos, o impacto ambiental representado aqui pela emissão de dióxido de carbono com a utilização dos respectivos insumos.
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Gardosi, Giulia. « Stima del potenziale di liquefazione in terreni alluvionali di recente deposizione (sito di Isola Serafini, PC) ». Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9464/.
Texte intégralRésumé :
With the support of data collected by CPT tests on-site, in this report, we try to estimate the liquefaction potential in soils at high risk, due to the presence of sandy horizons. We began by acquiring some basic theory about the topic with the help of texts, articles and documents found in the web. The notions found here were consequently applied to two concrete case studies.
In the first part of the work, the phenomenon of liquefaction is analyzed at a theoretical level. Moreover, we want to find out the trigger factors and the possible side effects whenever this event occurs.
In the second part of the work, we re-elaborated the data concerning tip resistance (qc) and resistance to friction side (fs) obtained by CPT tests taken in proximity of San Carlo (FE) and Isola Serafini (PC). We particularly chose to go through this specific process to estimate the land liquefaction potential.
The main purpose is finally to compare the results of both tests and to comment on them.
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Champigny, Pierre-Luc. « Biocompatibilité des bactéries lactiques et probiotiques et d'affinage avec des mycètes du camembert isolées de laits de terroir québécois ». Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28391/28391.pdf.
Texte intégralRésumé :
L’objectif de cette étude était de vérifier la biocompatibilité entre les mycètes du fromage Camembert et les bactéries lactiques (probiotiques ou d’affinage). La plupart des souches fongiques utilisées ont été isolées de laits en provenance du terroir québécois et deux laits d’origines différentes ont servi pour la fabrication de caillés modèles. La spectrophotométrie automatisée (SA) a été employée pour présélectionner des mélanges de souches mycéliennes et bactériennes biocompatibles. Des milieux à base de lait furent fermentés par des mycètes et étaient ensuite inoculés avec les bactéries. La croissance préalable des mycètes stimulait ou inhibait les bactéries, mais les effets étaient mineurs et variaient selon les souches. Par la suite, afin de confirmer ces résultats, des caillés modèles ont été inoculés simultanément par des combinaisons de bactéries et de mycètes. L’absence d’inhibition des bactéries par les mycètes observée en SA a été confirmée, mais les interactions en caillé modèle différaient de celles notées en SA en raison de l’évolution différente du pH dans les deux séries expérimentales. Finalement, des fromages Camembert probiotiques ont été fabriqués avec des souches du terroir et commerciales. Le Camembert s’est révélé un aliment intéressant pour favoriser la survie des bactéries lactiques. Par contre, aucun mélange de souches fongiques n’a été systématiquement meilleur qu’un autre pour stimuler la viabilité des probiotiques.This study was carried out to verify the biocompatibility between the mycetes of Camembert cheese and lactic cultures (probiotic and ripening strains). Most of the fungi strains used had been isolated from different milk sources over the province of Quebec (Canada) and two different kinds of milk were used to produce cheese slurries. Automated spectrophotometry (AS) was employed to screen some biocompatible pairings of mycete and bacterial strains. A milk medium was fermented by yeasts and moulds and then inoculated with bacteria. The previous growth of the mycetes was sometimes stimulatory and sometimes inhibitory, but the effects were minor and varied as a function of the strains. Subsequently, to confirm these AS results, cheese slurries were inoculated simultaneously with different strains combinations. Finally, pilot scale Camembert cheese was produced to verify its ability to support probiotic bacterial cultures viability. The absence of inhibition of the bacteria by the mycetes in SA was confirmed, but the interactions in the cheese slurries differed from those noted in AS because of the different pH patterns in the two experimental series. Camembert was shown to have potential to favour the viability of probiotic bacterial strains during ripening and storage. However, no mycete mix was systematically better than another to stimulate this viability.
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Fedrizzi, Samanta Maria Gobbo. « \"Produção de metabólitos antimicrobianos e sideróforos de isolados provenientes de Terra Preta Antropogênica da Amazônia Ocidental\" ». Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-20032007-081838/.
Texte intégralRésumé :
Os microrganismos atraem considerável atenção por serem uma fonte de compostos biotecnológicos e farmacêuticos. Diversos produtos naturais peptídicos produzidos por fungos e bactérias são sintetizados por grandes enzimas, conhecidas como peptídeo sintetase não ribossômica (NRPS) e policetídeo sintase (PKS). A bioprospecção dos microrganismos isolados do solo de Terra Preta Antropogênica (TPA) da Amazônia Ocidental é de grande importância para o conhecimento deste bioma tropical. Este estudo correlacionou a presença de sideróforos e de compostos antimicrobianos produzidos pelos microrganismos isolados de TPA e dos solos adjacentes com a presença dos genes que codificam para NRPS e PKS. Linhagens bacterianas foram isoladas das amostras do solo coletadas de 10, 20 e 40 cm de profundidade. Os isolados foram cultivados em meio líquido específico por 2 dias a 28oC. Um total de 143 isolados foi testado para a atividade de sideróforo e para isso, as linhagens foram inoculadas em um meio com baixa concentração de ferro (MM9) contendo o complexo cromoazurol S-Fe3. Do total, 72 isolados apresentaram reação positiva para a produção de sideróforo. O DNA genômico dos isolados foi extraído e a amplificação por PCR foi realizada usando iniciadores específicos para NRPS e PKS. Os resultados mostraram que quinze isolados apresentaram o gene que codifica para NRPS, vinte isolados para PKS e somente dez isolados apresentaram ambos os genes. A presença de genes de NRPS e PKS em 31% dos isolados testados sugere que a produção dos sideróforos possa ocorrer pela via não ribossomal. Dois isolados foram selecionados para estudos de identificação e caracterização dos compostos. O isolado TP11 foi identificado como Pseudomonas putida através de seqüenciamento do 16S rRNA e apresentou resultado negativo para hidroxamato e catecol, sugerindo que o tipo de sideróforo não possui nenhum destes grupos funcionais. O isolado TP16 foi identificado como Pseudomonas putida e apresentou produção de sideróforo do tipo catecol e hidroxamato, sugerindo a produção de mais de um sideróforo. Além disso, esta linhagem produziu um composto antimicrobiano, com atividade de sideróforo identificado por espectrometria de massas como pseudomonina com massa molar de 330 Da.Microorganisms have attracted considerable attention as a source for biotechnological and pharmaceutical agents. Several peptidic natural products synthesized by fungi and bacteria are assembled by large enzymes, referred as nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS). Bioprospection of microorganisms isolated from Anthropological Dark Earth soil of Brazilian Occidental Amazon is of great importance to the knowledge of this tropical biome. This study aimed to correlate the presence of siderophores and antimicrobial compounds produced by microorganisms isolated from Dark Earth and adjacent soils of Brazilian Amazon with the presence of genes encoding NRPS and PKS. Bacterial strains were isolated from soil samples collected at 10, 20 and 40 cm depth. The isolates were grown in specific liquid medium for 2 d at 28oC. A total of 143 isolates were screened for siderophore activity and for this, bacterial strains were inoculated on plates containing an iron-limited medium (MM9) amended with a chromeazurol S-Fe3 complex. From the total, seventy-two isolates showed positive reaction for siderophore production. Genomic DNA of the isolates was extracted and PCR amplification was carried out using specific primers for NRPS and PKS. The results showed that fifteen isolates presented NRPS, twenty isolates presented PKS and only ten isolates showed both genes. The presence of NRPS and PKS genes in 31% of the isolates tested suggests that production of siderophores may occur by a nonribosomal pathway. Two isolates were selected for further studies. Isolate TP11 was identified as Pseudomonas putida by 16S rDNA sequencing analysis and was negative for hydroxamate and catechol, suggesting that the siderophore type has no hydroxamate- or catechol-type functional groups. The isolate TP16 was identified as Pseudomonas putida and showed the production of catechol and hydroxamate siderophore-type, suggesting the production of more than one siderophore. In addition, this strain produced an antimicrobial compound, with siderophore activity identified through mass spectrometry as pseudomonine with a molar mass of 330 Da.
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Carmo, Edson Júnior. « Clonagem e caracterização enzimática de uma lipase isolada de uma biblioteca metagenômica de terra preta de índio ». Universidade Federal do Amazonas, 2017. http://tede.ufam.edu.br/handle/tede/5709.
Texte intégralRésumé :
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The advancement of molecular technologies in the scientific field has enabled the development of various forms of access to the genetic material of organisms in order to locate, map, isolate, characterize and decode the target genes of a particular individual or a set of individuals coexisting in a specific environment. Metagenomic studies are very promising in several areas of biotechnology, such as the discovery of new molecules of industrial biotechnological interest, the investigation of new antibiotics and drugs, the bioremediation of environments impacted with toxic metals and the prospection of various enzymes. The objective of this work was characterize enzymatically a previously screened lipase enzyme from Metagenomic Library of Terra Preta de Índio. Lipase gene sequence was isolated from the metagenomic library and expressed in Pichia pastoris under control of PGK promoter. Recombinant lipase was characterized by hydrolysis activity of lipid substrates and synthesis ability in organic solvent. In silico analyzes infer the identification of extracellular lipase belonging to the lipase family, superfamily -hydrolase and lipase activity molecular function. Enzyme was efficiently produced in P. pastoris and recombinant lipase showed activity of 374.59 U/mL hydrolyzing p-nitrophenyl palmitate, Vmax (ap.) 143,4 U/mL.min-1, Km (ap.) 1,4 mM and Kcat (ap.) 103,7 S-1. Enzyme had maximum activity at pH 8.0, temperature 90 ºC and remained stable at high temperatures. Synthesis ability was evaluated by the formation of ethyl laurate by esterification reaction of lauric acid with ethanol, yielding 70% conversion in 45 minutes. Recombinant protein is characterized as an alkaline, thermotolerant, activated by calcium, EDTA e detergents.
O avanço das tecnologias moleculares no campo científico, possibilitou o desenvolvimento de diversas formas de acesso ao material genético dos organismos, de forma a ser possível localizar, mapear, isolar, caracterizar e decodificar os genes alvo de um indivíduo particular ou de um conjunto de indivíduos coexistentes em um ambiente específico. Estudos metagenômicos são bastante promissores em diversas áreas da biotecnologia, como nas descobertas de novas moléculas de interesse biotecnológico industrial, na investigação de novos antibióticos e fármacos, na biorremediação de ambientes impactados com metais tóxicos e na prospecção de enzimas diversas. O objetivo deste trabalho foi caracterizar enzimaticamente uma enzima lipase previamente rastreada de uma Biblioteca Metagenômica de Terra Preta de Índio. A sequência correspondente ao gene de lipase foi isolada da biblioteca metagenômica, clonada e expressada em Pichia pastoris sob controle do promotor PGK. A lipase recombinante foi caracterizada pela atividade de hidrólise de substratos lipídicos e capacidade de síntese em solvente orgânico. Análises in silico da sequência proteica inferem a identificação de uma lipase extracelular pertencente à / - hidrolase e com função molecular para atividade lipásica. A enzima foi produzida eficientemente em P. pastoris e a lipase recombinante apresentou atividade de 374,59 U/mL hidrolisando p-nitrofenil palmitato, Vmax(ap.) 143,4 U/mL.min-1, Km(ap.) 1,4 mM e Kcat(ap.) 103,7 S-1. A enzima possuiu atividade máxima em pH 8,0, temperatura 90 ºC e se manteve estável em altas temperaturas. A capacidade de síntese foi avaliada pela formação de laurato de etila pela reação de esterificação do ácido láurico com etanol apresentando rendimento de 70% em 45 minutos de reação. A proteína recombinante se caracteriza como uma enzima alcalina, termotolerante, ativada por cálcio, EDTA e detergentes.
Livres sur le sujet "Isolats de terrain"
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LeBeuf, Marcel-Eugène. Crime organisé et police dans les communautés rurales et isolées du Canada : Une étude des perceptions des policiers/policières et de leurs interventions courantes : résultats préliminaires d'une recherche sur le terrain. Ottawa, Ont : Gendarmerie royale du Canada, 2006.
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Williams, Bruce. Albanian Cinema through the Fall of Communism. Nieuwe Prinsengracht 89 1018 VR Amsterdam Nederland : Amsterdam University Press, 2023. http://dx.doi.org/10.5117/9789462980150.
Texte intégralRésumé :
Albanian cinema truly represents a terra incognita for most of the world. Decidedly Europe’s most isolated country during the Cold War era, communist Albania had already been cut off from the West for centuries as a one of the western-most outposts of the Ottoman empire. Nonetheless, and unknown to most of the world, communist Albania had a vibrant cinema tradition. Although bound by official orthodoxy, the films of the state-run Kinostudio enterprise were surprisingly innovative and, at times, daringly subversive. This book opens with examinations of moving images in Albania from the Ottoman period, through those captured under independence and the Fascist occupation. It subsequently foregrounds transformations in Kinostudio, from the early optimism of socialist realism through the brooding social angst of the 1980s, which constitute a bridge to the socioeconomic concerns of Albanian films of the postcommunist period.
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Nigro, Giampiero, dir. Reti marittime come fattori dell’integrazione europea / Maritime Networks as a Factor in European Integration. Florence : Firenze University Press, 2019. http://dx.doi.org/10.36253/978-88-6453-856-3.
Texte intégralRésumé :
Il tema, di grande respiro, prende come punto di partenza il concetto braudeliano di Mediterraneo. La sua visione di un mare chiuso come una opportunità geografica per una integrazione economica fra popolazioni diverse per religioni, linguaggi ed entità etniche e politiche continua a funzionare come modello per studi applicati ad un ampio raggio di contesti. L’obiettivo che si è posta la 50ª Settimana di studi è stato quello di andare oltre lo studio dei singoli sistemi visti in modo isolato per combinare diverse analisi di mari aperti e chiusi o aree costiere, allo scopo di comprendere il ruolo di integrazione giocato in Europa dalle connessioni marittime. Poiché nelle civiltà preindustriali il trasporto per via d’acqua era più facile di quello via terra, è sembrato giunto il momento di richiamare l’attenzione sul modo in cui queste reti di relazione operavano a livello europeo e con i partner commerciali asiatici e nordafricani. Il volume prende le mosse dalle grandi tradizioni di ricerca su base regionale o tematica, che però sono state raramente integrate su una più ampia scala continentale. Immanuel Wallerstein ha elaborato il concetto braudeliano concettualizzandone le dimensioni interculturali e transnazionali e il ruolo nel sistema di divisione del lavoro. Egli lo chiamò un “sistema mondo”, non perché coinvolgesse il mondo intero, ma perché è più vasto di qualunque unità politica giuridicamente definita. E si tratta di una “economia mondo” perché il legame di base tra le varie parti del sistema è economico. I vari aspetti e le tradizioni regionali di ricerca sono stati collegati tra loro in un approccio coerente che si posto l'obiettivo di valutare: - Sulla base di quali elementi geografici, nautici, tecnici, economici, giuridici, sociali e culturali siano emerse le varie reti regionali, e come funzionavano, - Il carattere e il ruolo dei porti marittimi come punti nodali delle rotte marine e del loro hinterland, attraverso fiumi, canali e strade, - I legami commerciali e personali tra mercanti e armatori in vari porti, - In quale modo le reti regionali si collegavano tra di loro e come, nel corso del tempo, finirono per integrarsi in unità più ampie, - In quale modo le reti private, inizialmente costituite da organizzazioni di mercanti e navigatori, finirono per trattare con le autorità locali e, una volta cresciute, con gli stati e gli imperi, per proteggere i propri interessi
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Blevins, Brooks. A History of the Ozarks, Volume 1. University of Illinois Press, 2018. http://dx.doi.org/10.5622/illinois/9780252041914.001.0001.
Texte intégralRésumé :
A History of the Ozarks, Vol. I: The Old Ozarks is the first book-length account of life in the Ozark region of Missouri, Arkansas, and Oklahoma in the era before the Civil War. Placing the region’s story within the context of North American and United States history, The Old Ozarks follows the human story in the Middle American highlands from prehistoric times until the eve of the Civil War. Along the way it chronicles the rise and fall of the powerful Osages, the settlement of the French in the Mississippi Valley and the flood of Anglo-Americans on the frontier, the resettlement of immigrant Indians from the East, and the development of antebellum society in the diverse terrain of the Ozark uplift. Above all The Old Ozarks follows a narrative approach that focuses on the people whose activities and ambitions brought life to the region, from the Shawnee Quatawapea to Moses Austin, and in turn brings life to many long-forgotten individuals and the lifeways that they brought with them from Tennessee, Kentucky, and other parts of the Upland South. The storyline that flows throughout The Old Ozarks underscores not a region of isolated backwoodsmen but a regional variation of the American story.
Chapitres de livres sur le sujet "Isolats de terrain"
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Rosenberg, Jay F. « Wilfrid Sellars’ Philosophy of Mind ». Dans Wilfrid Sellars : Fusing the Images, 152–68. Oxford University PressOxford, 2007. http://dx.doi.org/10.1093/oso/9780199214556.003.0008.
Texte intégralRésumé :
Abstract Nowhere within philosophy is it more difficult to draw lines of demarcation than in an attempt to isolate the philosophy of mind as a coherent subregion of the total philosophical terrain. The philosophy of mind grades off smoothly into questions of epistemology (the structure of sensory awareness and perceptual cognition), of ontology (the nature and multiplicity of substances), of the theory of action, of the philosophy of language and representation, of moral and social and political philosophy, and nowadays even into questions centered in the philosophy of science, in the theory of theories.
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Kaimal, J. C., et J. J. Finnigan. « Spectra and Cospectra Over Flat Uniform Terrain ». Dans Atmospheric Boundary Layer Flows. Oxford University Press, 1994. http://dx.doi.org/10.1093/oso/9780195062397.003.0005.
Texte intégralRésumé :
Turbulent flows like those in the atmospheric boundary layer can be thought of as a superposition of eddies—coherent patterns of velocity, vorticity, and pressure— spread over a wide range of sizes. These eddies interact continuously with the mean flow, from which they derive their energy, and also with each other. The large “energy-containing” eddies, which contain most of the kinetic energy and are responsible for most of the transport in the turbulence, arise through instabilities in the background flow. The random forcing that provokes these instabilities is provided by the existing turbulence. This is the process represented in the production terms of the turbulent kinetic energy equation (1.59) in Chapter 1. The energy-containing eddies themselves are also subject to instabilities, which in their case are provoked by other eddies. This imposes upon them a finite lifetime before they too break up into yet smaller eddies. This process is repeated at all scales until the eddies become sufficiently small that viscosity can affect them directly and convert their kinetic energy to internal energy (heat). The action of viscosity is captured in the dissipation term of the turbulent kinetic energy equation. The second-moment budget equations presented in Chapter 1, of which (1.59) is one example, describe the summed behavior of all the eddies in the turbulent flow. To understand the conversion of mean kinetic energy into turbulent kinetic energy in the large eddies, the handing down of this energy to eddies of smaller and smaller scale in an “eddy cascade” process, and its ultimate conversion to heat by viscosity, we must isolate the different scales of turbulent motion and separately observe their behavior. Taking Fourier spectra and cospectra of the turbulence offers a convenient way of doing this. The spectral representation associates with each scale of motion the amount of kinetic energy, variance, or eddy flux it contributes to the whole and provides a new and invaluable perspective on boundary layer structure. The spectrum of boundary layer fluctuations covers a range of more than five decades: millimeters to kilometers in spatial scales and fractions of a second to hours in temporal scales.
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Tsitsipis, Lukas D. « On the Politics of Change ». Dans A Linguistic Anthropology of Praxis and Language Shift, 8–20. Oxford University PressOxford, 1998. http://dx.doi.org/10.1093/oso/9780198237310.003.0002.
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Abstract The research reported here is a sociolinguistic and anthropological linguistic study of language change conducted mainly in two Albanian-speaking communities in southern Greece: Spáta in the district of Attika, and Kiriáki in the district of Biotia. Kiriáki represents a more conservative community, being geographically isolated in a mountainous, rough physical terrain, whereas Spáta represents a more modernized community due to its vicinity to the capital city of Athens. Other communities have been surveyed to be mentioned in the analysis of the relevant data.
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Jack, Max. « Introduction ». Dans Insurgent Fandom, 1–30. Oxford University Press, 2024. http://dx.doi.org/10.1093/oso/9780197686911.003.0001.
Texte intégralRésumé :
Abstract Rapidly proliferating across football stadia throughout Europe in the early 2000s, ultra has developed into a transnational subculture and a social movement built around the fans’ stylistic coordination of crowd action—that which is intended as a form of support for their respective teams on the field. Exploring ultras’ all-encompassing lifestyles dedicated to cultivating heightened sensory environments, atmosphere is conceptualized in the text as an affective terrain of socialization and public address that serves as a collective process of imagining and implementing social alternatives to the isolating effects of neoliberal capitalism. The chapter charts the myriad conflicting strategies of various state apparatuses that aim to mold ultra subjectivity and affect in public space, forming a mutually constitutive interrelationship between hardcore fans and the state that radicalizes and isolates them further.
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Harriss, Gerald. « Agrarian Society ». Dans Shaping the Nation, 209–55. Oxford University PressOxford, 2005. http://dx.doi.org/10.1093/oso/9780198228165.003.0007.
Texte intégralRésumé :
Abstract Late medieval England exhibited infinite variations in the use of the land, often within very localized areas. These were determined by the terrain and soil, economic location, and social and agrarian organization. I shall first survey the broad diversity of its regions, even if the range of their micro-economies can only be hinted at. A distinction is usually drawn between upland and lowland economies. The former, relying on rough pasture and woodland with little and poor arable, was mainly dependent on livestock, notably sheep and pigs, with timber and mineral extraction providing an industrial element. Settlement was dispersed in isolated farms and hamlets, held by free tenants and worked in severalty.
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Cooper, Sandi E. « Peace Movements and the Challenge of Nationalism 1850–1889 ». Dans Patriotic Pacifism, 30–59. Oxford University PressNew York, NY, 1991. http://dx.doi.org/10.1093/oso/9780195057157.003.0003.
Texte intégralRésumé :
Abstract To the exhilarated organizers of the 1849 Paris International Peace Congress, a future for annual conventions of “friends of peace” seemed assured. Expecting to repeat their success, they had convened in the Paulskirche in Frankfurt in 1850. By 1851, however, when organizers called for a congress in Manchester, political reality intruded. Continental participation dwindled. The “international” meeting had become mainly British. For the next two decades, peace movements on both sides of the Atlantic underwent persistent battering. During the 1850s, 1860s, and l870s-with the remarkable exception in 1867–1871-a few, hardy, isolated campaigners strug gled against ridicule and indifference. The volcanic political terrain following the revolutions and counterrevolutions of 1849-1851 drove peace from the agendas of many potential supporters.
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Stratton Hild, Elaine. « With the Laity ». Dans Music in Medieval Rituals for the End of Life, 83–107. Oxford University PressNew York, 2024. http://dx.doi.org/10.1093/oso/9780197685914.003.0004.
Texte intégralRésumé :
Abstract Chapter 3 leaves behind the powerful, urban centers of Rome and Sens and moves to Orsières, a village isolated in the mountainous terrain of southwestern Switzerland (Canton Valais). In a stroke of luck for historians, a manuscript associated with this small community survives from the fourteenth century. The source offers a rare opportunity to better understand the liturgical practices conducted by a lay community at the time of an individual’s death. This chapter argues that the deathbed liturgy of Orsières shares profound similarities with those of prominent religious institutions, while mirroring none exactly. The chapter concludes that rituals for the dying remained unstandardized even into the fourteenth century, and that the community of Orsières maintained a version that circulated locally.
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Rodrigues, Vanessa Maria Silva, Camila Cristina Pires de Brito, Thâmara Cristina Araújo Silva, Susmara Silva Campos et Simone Ferreira Teixeira. « COMPOSIÇÃO TRÓFICA DA ICTIOFAUNA DE UMA ÁREA MARGINAL SAZONALMENTE ISOLADA ». Dans Ciências Biológicas e da terra : princípios fundamentais. Editora Conhecimento Livre, 2020. http://dx.doi.org/10.37423/200702123.
Texte intégral
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Mavroidis, I., et R. F. Griffiths. « Investigation of the Effect of Atmospheric Stability on Characteristic Decay Times of Tracer Concentrations in the Wake of an Isolated Obstacle ». Dans Mixing and Dispersion in Stably Stratified Flows, 493–504. Oxford University PressOxford, 1999. http://dx.doi.org/10.1093/oso/9780198500155.003.0030.
Texte intégralRésumé :
Abstract The effect of atmospheric stability on characteristic decay times of a gas tracer in the near-wake of an isolated obstacle has been investigated. Field experiments have been conducted in flat terrain using a model 2 m cube. Two cube orientations were considered, with the mean wind direction either normal or at 45 degrees to the cube. The experiments involved the release of a tracer gas upwind of the obstacle, with fast-response detectors measuring concentrations at various points in the obstacle wake, at a frequency of 100 Hz. Tracer gas was released continuously for a limited period in order to fill the wake. Thereafter, the source was switched off using a solenoid valve, and the concentration in the wake was found to decay in an exponential manner
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König, Jason. « Mountain Saints in Late Antique Christian Literature ». Dans The Folds of Olympus, 283–304. Princeton University Press, 2022. http://dx.doi.org/10.23943/princeton/9780691201290.003.0016.
Texte intégralRésumé :
This chapter looks at frequent descriptions of inhabiting mountain territory and in the saints' lives that survive from late antiquity right through the medieval period, many of which have mountain settings. It highlights the flexibility of the Greek term oros, which can refer to mountain peaks where some holy men are said to have occupied sites on or near the summits. Oros also applies to the rocky expanses of wild terrain at lower altitude, especially in late antique Egypt, where it is used almost interchangeably with the Greek word erēmos. The chapter describes the authors of the saints' lives that offer a broadly positive vision of isolated mountain lifestyles that are cut off from urban civilisation. Men and women who practised asceticism became heroes of holiness through the texts that presented them to the wider world.
Actes de conférences sur le sujet "Isolats de terrain"
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Prewitt, Jack, Joseph Milluzzo et John Tritschler. « Effects of Sloped Terrain on In-Ground-Effect Hover Performance for an Isolated Rotor ». Dans Vertical Flight Society 79th Annual Forum & Technology Display. The Vertical Flight Society, 2023. http://dx.doi.org/10.4050/f-0079-2023-18178.
Texte intégralRésumé :
The present work reports the results of an investigation into the performance effects of hovering over sloped terrain for a laboratory-scale rotor. A pair of 1 : 13.24 scale OH-58C rotor blades were operated over a six-axis ground plane which could vary in angle, and rotor performance measurements were collected using a six-axis load cell. The design of the experiment included variation of the ground plane angle, collective blade pitch angle, and rotor height above the ground. The results showed that sloped terrain had a measurable performance degradation for all tested hover regimes, which was found to be greatest at combinations of low rotor hub heights and low blade loading coefficients with degradations up to 9.3% when compared to hover over level terrain. In certain flight regimes, hover over sloped terrain required up to 2.6% more power than hover out-of-ground effect. An increase in blade loading coefficient was seen to improve hover performance over sloped terrain by up to 4.5% rather than degrade performance, which is typically seen when hovering over level terrain. Finally, a model of hover over sloped terrain using a semi-empirical model is presented and discussed.
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Okundamiya, Michael S., et Owen Omorogiuwa. « Analysis of an isolated micro-grid for nigerian terrain ». Dans 2016 IEEE 59th International Midwest Symposium on Circuits and Systems (MWSCAS). IEEE, 2016. http://dx.doi.org/10.1109/mwscas.2016.7870060.
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Tritschler, John, Joseph Milluzzo et John Holder. « Performance Effects of Hover In-Ground-Effect over Sloped Terrain ». Dans Vertical Flight Society 75th Annual Forum & Technology Display. The Vertical Flight Society, 2019. http://dx.doi.org/10.4050/f-0075-2019-14520.
Texte intégralRésumé :
The present work reports the results of a research investigation into the performance effects of hovering over sloping terrain as characterized in both laboratory-scale testing of an isolated rotor as well as flight testing of a UH-72A helicopter. The design of the experiment included variation in the slope magnitude, rotor hub height, thrust/power setting, and aircraft orientation with respect to the slope (for the flight test data). In addition to performance measurements, flow field measurements of the laboratory flows were computed via particle image velocimetry, and rotor wake visualizations from flight testing were created via background-oriented Schlieren post-processing techniques. The results show that hovering over sloped terrain results in performance effects that are both nonintuitive and operationally significant. Additionally, the hover performance data collected over level terrain show that inground-effect hover performance is truly a complicated, interdependent relationship that includes multiple specifying conditions; it is not simply a one-dimensional function of hub height above the ground plane. Lastly, a comparison of the flow field measurements from laboratory testing and the rotor wake visualization from flight testing is presented to speculate on the fundamental flow field mechanisms at play and propose an approach for a more rigorous reconciliation of these two data sets in future studies.
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Oswell, James M., et Gualberto Chiriboga. « Geotechnical Aspects of a Pipeline Rupture in Ecuador : Factors and Mitigation ». Dans ASME 2013 International Pipeline Geotechnical Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ipg2013-1953.
Texte intégralRésumé :
In February 2009 a pipeline rupture occurred along a sloped section of the Oleoducto de Crudos Pesados (OCP) Ecuador S.A. pipeline. The spill resulted in crude oil flowing down the hillside and into the Rio Santa Rosa. Post rupture investigations were initiated to identify the geotechnical factors that may have contributed to the incident and what mitigation may be necessary to ensure future pipeline integrity. The investigation consisted of several activities including detailed site reconnaissance by a geotechnical engineering team and installation of slope inclinometers to assess ground movements. The intent of the slope inclinometers was to determine the depth, areal extent and rate of ground movement, if any. The post rupture site reconnaissance identified a number of terrain features consistent with shallow ground movement mechanisms. The presence of hummocky terrain could be the result of ground movement or an artifact of the use of the slope as cattle pasture. Five slope inclinometers were installed to assess the slope movements within the project site. Four slope indicators were installed up-slope of the pipeline right-of-way to provide some lateral boundary to the ground movement area. The slope inclinometers showed that in the months following the pipeline rupture the terrain upslope of the pipeline right-of-way was moving at a relative constant rate of about 0.45 mm/day. As a result of the geotechnical investigations an integrity mitigation plan was developed. This included ongoing slope movement monitoring, regular site reconnaissance and placement of the pipeline above ground on “sleepers” to isolate the pipeline from the underlying creeping slope. To-date, these mitigations have been successful in reducing strain on the pipeline.
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Bagci, Suat, et Adel Al-Shareef. « An Investigation of Slug Flow in Hilly Terrain Pipelines ». Dans ASME 2001 Engineering Technology Conference on Energy. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/etce2001-17063.
Texte intégralRésumé :
Abstract Two-phase flow in hilly terrain pipelines can cause significant practical operating problems. When slugs flow in a hilly terrain pipeline that contains sections of different inclinations they undergo a change of length and slug flow characteristics as the slug move from section to section. In addition, slugs can be generated at low elbows, dissipate at top elbows and shrink or grow in length as they travel along the pipe. A mathematical model and a computer program was developed to simulate these phenomena. The model was based on the sink/source concept at the pipeline connections. A connection between two pipeline sections of different slopes was conveniently called elbow. An elbow accumulates liquid as a sink, and releases liquid as a source. The sink/source has a characteristic capacity of its own. This capacity is positive if the liquid can indeed be accumulated at the elbow or negative if the liquid is actually drained away from the elbow. This type of treatment effectively isolates the flow upstream from an elbow from that downstream, while still allowing flow interactions between two detailed pipeline sections. The hydrodynamic flow model was also used to calculate the film liquid holdup in horizontal and inclined pipelines. The model can successfully predict the liquid film holdup if the liquid film height is assumed to be uniform through the gas pocket. Many other models were used to calculate all the needed parameters to perform the sink/source model. The overall effect of a hill or terrain on slug flow depends on the operating flow rates and pipeline configurations. For special case of near constant slug frequency corresponding to moderately high superficial liquid and gas velocities, this effect was found to be small. The changes in the film characteristics between two adjacent pipeline sections were found to be mostly responsible for the pseudo-slug generation, slug growth and dissipation in the downstream pipeline sections. The film liquid holdup decreased with increasing pipe diameter. The unit slug length increased at the upstream inclined pipes and decreased at the downstream inclined pipes with increasing pipe diameter. The possibility of pseudo-slug generation was increased at large pipe diameters even at high sink capacities. At low sink capacities, no pseudo-slugs were generated at high superficial velocities. The slug flow characteristics was more effected by low superficial gas and liquid velocities, large pipe diameters and shallow pipeline inclinations.
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Jafari, S., N. Chokani et R. S. Abhari. « Terrain Effects on Wind Flow : Simulations With an Immersed Boundary Method ». Dans ASME 2011 Turbo Expo : Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46240.
Texte intégralRésumé :
The modelling of the wind resource over arbitrary topography is required to optimize the micrositing of wind turbines. Most solvers use classical body-fitted grid for simulations. In such an approach, to cover the wind rose using a rectangular domain, a dedicated mesh must be generated for each direction. Moreover, over complex terrain, additional numerical errors are introduced in the solver due to coordinate transformations. To overcome these challenges and to facilitate the grid generation process, an immersed boundary method is developed in connection with a RANS solver in order to simulate turbulent atmospheric flows over arbitrary topography. In this method, a Cartesian grid is used and the boundary condition on the terrain surface is modelled within the solver using a “direct forcing” approach. With the immersed boundary method a rectangular grid can be used to simulate the flow field for all wind directions and only a rotation of the digital elevation map is required. Ghost cells are used to enforce the desired boundary condition at the immersed surface. The immersed boundary method developed in this work is used to simulate the flow in connection with both Baldwin-Lomax and kω turbulence models. The performance of the method is examined for the flow over a two-dimensional hill. Results are compared with experimental data as well as a classical body-fitted grid to isolate the effect of the boundary conditions. The comparisons show good agreement among all the results. The results for the three-dimensional wind flow simulation over the Askervein Hill test case are also presented, and show the capability of the immersed boundary method in a full-scale scenario.
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Quesada-García, Santiago, et María Lozano-Gómez. « Levantamiento y análisis espacial de la presa de Garganta del Ciervo y el paisaje regado por el embalse andalusí Albuhera (s. XII) ». Dans FORTMED2024 - Defensive Architecture of the Mediterranean. Valencia : Universitat Politàcnica de València, 2024. http://dx.doi.org/10.4995/fortmed2024.2024.18104.
Texte intégralRésumé :
The study of historic dams and water reservoirs is a little-explored field, unevenly addressed by historiography, architecture, and civil engineering, possibly because most of these remains are isolated and dispersed in rural areas and places that are difficult to access. This circumstance, among others, makes it difficult for them to be adequately known and leads to a lack of graphic analysis of these types of hydraulic infrastructures and the landscapes associated with them. This work presents one of the few known examples of Andalusi storage dams or reservoirs. Its survey is approached not as an isolated object or remain but as an inseparable part of the landscape it is part of. To this end, a specific methodology is designed that geo-references the data, constructs a digital terrain model and topographical surveys with use of UAV, and ends with a 3D reconstruction of the preserved remains, characterising them with a dense point cloud. The results obtained shed light on a mediaeval landscape irrigated by an Albuhera, or “small sea” of water, dammed by the Garganta del Ciervo dam, a river barrier built with stone edges and lime in the mid-12th century in the Sierra de Segura de Jaén (Spain).
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Neuhaus, Peter D., et H. Kazerooni. « Human Assisted Walking Robot ». Dans ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0240.
Texte intégralRésumé :
Abstract The design goal was to invent a machine that could successfully maneuver heavy loads in isolated areas for extended periods of time. The motivation was to reduce the complexity of autonomous walking robots by involving the human in the operation of the machine. By taking advantage of the intelligence of the operator, the complexity of bipedal locomotion was reduced to tractable problem. The result of this research is that a two-legged, single actuated degree of freedom, walking machine was designed, built, and tested. The robot successfully navigated terrain including steep inclines and stairs. Additionally, a mechatronic control system was added to provide for smooth speed control and regulation. The leg driving architecture, the double four-bar linkage, designed for this machine can be extended to produce simplified four- and six-legged walking machines. The preliminary results can be used to extend this concept to a machine with an actuated balance assist system based on the human operator’s interaction with the machine.
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Lima, Vinicius Emanuel Brito, Andre Vieira Dalcim, Renan Angrizani Oliveira, Vanessa Cezar Simonetti et Rossana Cristina Rossoni Figueira. « AVALIAÇÃO DE MATERIAIS ISOLANTES NO PROCESSO DE GERAÇÃO DE ENERGIA ELÉTRICA COM PLANTAS DO TIPO SUCULENTAS ». Dans II Congresso On-line Internacional de Sustentabilidade. Revista Multidisciplinar de Educação e Meio Ambiente, 2021. http://dx.doi.org/10.51189/rema/2668.
Texte intégralRésumé :
Introdução: O acesso à energia elétrica é um requisito básico de cidadania. Entretanto, aproximadamente 800 milhões de pessoas não possuem tal recurso, sendo considerado um grande desafio global no século XXI. Devido a crescente preocupação com as mudanças climáticas, estamos vivenciando uma tendência em desenvolvimento e mudança das matrizes energéticas atuais para fontes renováveis e limpas. Objetivo: Objetivou-se avaliar a eficiência na geração de energia elétrica usando plantas do tipo suculentas (Sedum burrito e Crassula ovata) em recipientes de diferentes materiais isolantes (argila e polietileno) e diretamente na terra. Materiais e métodos: Foram utilizados 10 (dez) recipientes com volume de 0,5 L. Cada vaso apresentava um espécime de suculenta em solo humoso. Para o circuito 1, utilizou-se 5 (cinco) recipientes feitos de cerâmica. Já para o circuito 2, empregou-se 5 (cinco) vasos confeccionados de polietileno. Para o circuito 3, o método foi aplicado diretamente na terra. Na produção dos eletrodos, foram utilizadas placas de cobre (cátodo) e zinco (ânodo), colocando-se um cátodo e um ânodo por vaso (circuitos 1 e 2), sendo o diferencial do circuito 3 a ausência do isolante elétrico. Estas placas foram interligadas em série por fios de cobre não esmaltados. As medições das tensões foram feitas com os eletrodos totalmente enterrados e semienterrados, respectivamente, a partir de um multímetro digital. Resultados: Dessa forma, o circuito 1 gerou 4,2V (enterrados) e 2,8V (semienterrado). No circuito 2, mediu-se 6,9V e 3,8V. Os valores foram suficientes para alimentar 2 (duas) (circuito 1) e 3 (três) (circuito 2) lâmpadas de LED de tensão nominal de 2V e corrente de 20mA. Já o circuito 3, apresentou tensão praticamente nula, visto que o solo funciona como dispersor de elétrons (fio terra). Conclusão: Visando o conceito de sustentabilidade, o estudo aplica uma metodologia sustentável da geração de uma pequena fonte de energia elétrica limpa e renovável. A metodologia não apresenta dificuldade para aplicação e montagem, uma vez que emprega materiais de fácil acesso. Os resultados de tensão elétrica obtidos experimentalmente sugerem possível alternativa ao uso crescente e irracional dos recursos naturais, também podendo ser utilizado como material de educação ambiental.
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Pontaza, Juan P., et Raghu G. Menon. « On the Numerical Simulation of Fluid-Structure Interaction to Estimate the Fatigue Life of Subsea Pipeline Spans : Effects of Wall Proximity ». Dans ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20804.
Texte intégralRésumé :
Subsea pipelines laid on uneven terrain typically have segments of unsupported spans, referred to as “free spans”. Alternatively, subsea pipelines lying on loose and fine gravel or sand may develop free spans due to sea bottom being scoured out due to current action. This paper is concerned with the numerical simulation of fluid-structure interaction (FSI) to predict the response of free spans exposed to sea bottom currents. When exposed to sea bottom currents these spans may experience vortex-induced vibrations (VIV), which may cause fatigue damage to the pipeline. The VIV response of the pipe span is predicted by coupling a three-dimensional viscous incompressible Navier-Stokes solver with a nonlinear beam finite element solver. Parameters such as turbulence in the flow, proximity of the seabed, pipe sagging due to submerged weight, and pipe-soil interaction, are all accounted for in the FSI simulation. We pay special attention to the effect of seabed / wall proximity on VIV. Design guidelines for free spans are typically based on VIV amplitude and frequency responses for isolated pipes, with little regard to effects of seabed / wall proximity. This may result in overly conservative designs and/or expensive span remediation recommendations, when in reality no span remediation is required. Two examples of field applications are presented.
Rapports d'organisations sur le sujet "Isolats de terrain"
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Salcido, Charles, Patrick Wilson, Justin Tweet, Blake McCan, Clint Boyd et Vincent Santucci. Theodore Roosevelt National Park : Paleontological resource inventory (public version). National Park Service, mai 2022. http://dx.doi.org/10.36967/nrr-2293509.
Texte intégralRésumé :
Theodore Roosevelt National Park (THRO) in western North Dakota was established for its historical connections with President Theodore Roosevelt. It contains not only historical and cultural resources, but abundant natural resources as well. Among these is one of the best geological and paleontological records of the Paleocene Epoch (66 to 56 million years ago) of any park in the National Park System. The Paleocene Epoch is of great scientific interest due to the great mass extinction that occurred at its opening (the Cretaceous–Paleogene extinction event), and the unusual climatic event that began at the end of the epoch (the Paleocene–Eocene Thermal Maximum, an anomalous global temperature spike). It is during the Paleocene that mammals began to diversify and move into the large-bodied niches vacated by dinosaurs. The rocks exposed at THRO preserve the latter part of the Paleocene, when mammals were proliferating and crocodiles were the largest predators. Western North Dakota was warmer and wetter with swampy forests; today these are preserved as the “petrified forests” that are one of THRO’s notable features. Despite abundant fossil resources, THRO has not historically been a scene of significant paleontological exploration. For example, the fossil forests have only had one published scientific description, and that report focused on the associated paleosols (“fossil soils”). The widespread petrified wood of the area has been known since at least the 19th century and was considered significant enough to be a tourist draw in the decades leading up to the establishment of THRO in 1947. Paleontologists occasionally collected and described fossil specimens from the park over the next few decades, but the true extent of paleontological resources was not realized until a joint North Dakota Geological Survey–NPS investigation under John Hoganson and Johnathan Campbell between 1994–1996. This survey uncovered 400 paleontological localities within the park representing a variety of plant, invertebrate, vertebrate, and trace fossils. Limited investigation and occasional collection of noteworthy specimens took place over the next two decades. In 2020, a new two-year initiative to further document the park’s paleontological resources began. This inventory, which was the basis for this report, identified another 158 fossil localities, some yielding taxa not recorded by the previous survey. Additional specimens were collected from the surface, among them a partial skeleton of a choristodere (an extinct aquatic reptile), dental material of two mammal taxa not previously recorded at THRO, and the first bird track found at the park. The inventory also provided an assessment of an area scheduled for ground-disturbing maintenance. This inventory is intended to inform future paleontological resource research, management, protection, and interpretation at THRO. THRO’s bedrock geology is dominated by two Paleocene rock formations: the Bullion Creek Formation and the overlying Sentinel Butte Formation of the Fort Union Group. Weathering of these formations has produced the distinctive banded badlands seen in THRO today. These two formations were deposited under very different conditions than the current conditions of western North Dakota. In the Paleocene, the region was warm and wet, with a landscape dominated by swamps, lakes, and rivers. Great forests now represented by petrified wood grew throughout the area. Freshwater mollusks, fish, amphibians (including giant salamanders), turtles, choristoderes, and crocodilians abounded in the ancient wetlands, while a variety of mammals representing either extinct lineages or the early forebearers of modern groups inhabited the land. There is little representation of the next 56 million years at THRO. The only evidence we have of events in the park for most of these millions of years is isolated Neogene lag deposits and terrace gravel. Quaternary surficial deposits have yielded a few fossils...