(Table 2) Zn/Si ratios for sponge spicules from sediment core samples

The zinc concentration of siliceous sponge spicules was determined from spicules recovered from four sediment cores spanning the last 160 kyr, from the Campbell Plateau region southeast of New Zealand. Zinc/Si results showed little difference between Holocene and glacial aged spicules. An increase in Zn/Si was observed for core Y14, where Zn/Si peaked at about 0.6 ?mol/mol during marine isotope stages 5a-5b. To better understand the role carbon export has on sponge Zn/Si, we explored the strong relationship observed between surficial sediment particulate organic carbon (POC) and the Zn/Si of sponge silica and related this to sediment trap POC flux estimates. Conversion of the Zn/Si records to benthic POC fluxes suggests that there has been little change in the amount of POC reaching Campbell Plateau sediments over the past 30 kyr. These results suggest that surface productivity over the Campbell Plateau has remained relatively low over the past 160 kyr and suggests that glacial productivity was not significantly higher than the present day. Finally, this work reveals that living marine sponges appear to act as the biological equivalents of moored sediment traps, recording the flux of POC to the seafloor by archiving zinc associated with sinking POC in the growing silica skeleton.

Determinação de teor de biodieseis de algodão e pinhão manso em misturas com diesel usando espectroscopia no infravermelho médio e quadrados mínimos parciais

Biodiesel is a renewable fuel derived from vegetable oils or animal fats, which can be a total or partial substitute for diesel. Since 2005, this fuel was introduced in the Brazilian energy matrix through Law 11.097 that determines the percentage of biodiesel added to diesel oil as well as monitoring the insertion of this fuel in market. The National Agency of Petroleum, Natural Gas and Biofuels (ANP) establish the obligation of adding 7% (v/v) of biodiesel to diesel commercialized in the country, making crucial the analytical control of this content. Therefore, in this study were developed and validated methodologies based on the use of Mid Infrared Spectroscopy (MIR) and Multivariate Calibration by Partial Least Squares (PLS) to quantify the methyl and ethyl biodiesels content of cotton and jatropha in binary blends with diesel at concentration range from 1.00 to 30.00% (v/v), since this is the range specified in standard ABNT NBR 15568. The biodiesels were produced from two routes, using ethanol or methanol, and evaluated according to the parameters: oxidative stability, water content, kinematic viscosity and density, presenting results according to ANP Resolution No. 45/2014. The built PLS models were validated on the basis of ASTM E1655-05 for Infrared Spectroscopy and Multivariate Calibration and ABNT NBR 15568, with satisfactory results due to RMSEP (Root Mean Square Error of Prediction) values below 0.08% (<0.1%), correlation coefficients (R) above 0.9997 and the absence of systematic error (bias). Therefore, the methodologies developed can be a promising alternative in the quality control of this fuel.

Effect of wind on operating cost based cruise speed reduction for delay absorption

En route speed reduction can be used for air traffic flow management (ATFM), e.g., delaying aircraft while airborne or realizing metering at an arrival fix. In previous publications, the authors identified the flight conditions that maximize the airborne delay without incurring extra fuel consumption with respect to the nominal (not delayed) flight. In this paper, the effect of wind on this strategy is studied, and the sensitivity to wind forecast errors is also assessed. A case study done in Chicago O’Hare airport (ORD) is presented, showing that wind has a significant effect on the airborne delay that can be realized and that, in some cases, even tailwinds might lead to an increase in the maximum amount of airborne delay. The values of airborne delay are representative enough to suggest that this speed reduction technique might be useful in a real operational scenario. Moreover, the speed reduction strategy is more robust than nominal operations against fuel consumption in the presence of wind forecast uncertainties.

Intégration des connaissances théoriques et pratiques de l'analyse financière externe et interne dans le but d'un diagnostic de la situation financière

L'analyse de la situation financière de l'entreprise sert à la prise de décision pour les parties intéressées à l'intérieur de l'entreprise, soit le gestionnaire et parfois le propriétaire et les autres qui se trouvent à l'extérieur, tels l'investisseur, le ministère du revenu, le banquier et le consultant. Dépendamment de l'utilisateur, l'information disponible n'est pas la même. L'investisseur, le banquier et le ministère du revenu doivent analyser l'entreprise à partir des données comptables publiées. Mais, les états financiers cachent parfois certaines réalités, tel un exercice financier ne représentant pas la saisonnalité des activités. De même les stocks de fin d'exercice ne représentent pas nécessairement le niveau du stock moyen. Les échéances de paiement surviennent peut-être au début plutôt qu'uniformément au cours de l'exercice. La signature de contrats importants pourra avoir des répercussions qu'au cours de l'exercice suivant. L'information interne seule peut répondre à ces questions. De plus, le résultat net publié dans les états financiers renferme certaines lacunes dont l'analyste doit tenir compte : 1- L'amortissement et l'évaluation des comptes-clients comportent une bonne part de subjectivité; 2- L'existence de plusieurs méthodes d'évaluation des stocks amène des problèmes de comparabilité, surtout lorsque ces postes ont une relative importance; 3- La dépréciation monétaire non prise en compte dans les états financiers diminue la comparabilité d'un exercice à l'autre et n'assure pas la préservation du patrimoine. Ainsi, les dividendes peuvent être versés au-delà de ce qu'il serait prudent de verser pour assurer la capacité de fonctionnement; 4- En période de prospérité, l'entreprise tentera de minimiser son bénéfice comptable afin de diminuer sa charge fiscale alors qu'en période de déficit, elle tentera de maximiser son bénéfice comptable pour rassurer les propriétaires et les prêteurs; 5- L'inflation accentue les difficultés de comparaison. Il faudra donc tenir compte de l'inflation pour apprécier l'évolution réelle du résultat; 6- La comparaison avec plusieurs entreprises est quelque peu biaisée dû au choix des pratiques comptables exercées sur plusieurs postes. Les critères de comparaison devront donc être le moins possible dépendants de choix de pratiques comptables. Malgré l'existence de ces déformations comptables, les états financiers demeurent une source importante d'informations. Mais les forces et les faiblesses de l'entreprise s'en trouvent plus ou moins cachées. Comme le gestionnaire et le consultant ont accès aux données non publiées par l'entreprise, les résultats des activités et les données sur la qualité de la gestion interne peuvent donc être plus détaillés, et plus proches de la réalité. L'information publique, ne permet que de détecter les grandes lignes de la situation financière de l'entreprise. Les ouvrages en finance ne traitent que très peu de ces facteurs internes et du lien entre l'information interne et l'information externe. Le but de notre étude a été de créer un modèle de diagnostic de la situation financière, dans un premier temps, issu de la théorie et reposant sur les données externes et internes à l'entreprise. Dans un deuxième temps, nous avons construit un modèle plus complet qui tienne compte des interrelations des postes des états financiers et de l'interprétation faite par les praticiens, et dont la théorie ne fait pas état. L'intégration des connaissances des praticiens au modèle théorique initial et l'utilisation des données internes à l'entreprise, devraient permettre de porter un diagnostic plus éclairé de la situation financière de l'entreprise.

Análise de métodos para aplicação de ventilação natural em projetos de edificações em Natal-RN

Natural ventilation is an efficient bioclimatic strategy, one that provides thermal comfort, healthful and cooling to the edification. However, the disregard for quality environment, the uncertainties involved in the phenomenon and the popularization of artificial climate systems are held as an excuse for those who neglect the benefits of passive cooling. The unfamiliarity with the concept may be lessened if ventilation is observed in every step of the project, especially in the initial phase in which decisions bear a great impact in the construction process. The tools available in order to quantify the impact of projected decisions consist basically of the renovation rate calculations or computer simulations of fluids, commonly dubbed CFD, which stands for Computational Fluid Dynamics , both somewhat apart from the project s execution and unable to adapt for use in parametric studies. Thus, we chose to verify, through computer simulation, the representativeness of the results with a method of simplified air reconditioning rate calculation, as well as making it more compatible with the questions relevant to the first phases of the project s process. The case object consists of a model resulting from the recommendations of the Código de Obras de Natal/ RN, customized according to the NBR 15220. The study has shown the complexity in aggregating a CFD tool to the process and the need for a method capable of generating data at the compatible rate to the flow of ideas and are discarded during the project s development. At the end of our study, we discuss the necessary concessions for the realization of simulations, the applicability and the limitations of both the tools used and the method adopted, as well as the representativeness of the results obtained

Análise de componentes arquitetônicos para potencialização da ventilação natural com ênfase em captadores de vento

The building envelope is the principal mean of interaction between indoors and environment, with direct influence on thermal and energy performance of the building. By intervening in the envelope, with the proposal of specific architectural elements, it is possible to promote the use of passive strategies of conditioning, such as natural ventilation. The cross ventilation is recommended by the NBR 15220-3 as the bioclimatic main strategy for the hot and humid climate of Natal/RN, offering among other benefits, the thermal comfort of occupants. The analysis tools of natural ventilation, on the other hand, cover a variety of techniques, from the simplified calculation methods to computer fluid dynamics, whose limitations are discussed in several papers, but without detailing the problems encountered. In this sense, the present study aims to evaluate the potential of wind catchers, envelope elements used to increase natural ventilation in the building, through CFD simplified simulation. Moreover, it seeks to quantify the limitations encountered during the analysis. For this, the procedure adopted to evaluate the elements implementation and efficiency was the CFD simulation, abbreviation for Computer Fluid Dynamics, with the software DesignBuilder CFD. It was defined a base case, where wind catchers were added with various settings, to compare them with each other and appreciate the differences in flows and air speeds encountered. Initially there has been done sensitivity tests for familiarization with the software and observe simulation patterns, mapping the settings used and simulation time for each case simulated. The results show the limitations encountered during the simulation process, as well as an overview of the efficiency and potential of wind catchers, with the increase of ventilation with the use of catchers, differences in air flow patterns and significant increase in air speeds indoors, besides changes found due to different element geometries. It is considered that the software used can help designers during preliminary analysis in the early stages of design

Análise da fluência em vigas de concreto armado simplesmente apoiadas usando o método dos elementos finitos

Reinforced concrete creep is a phenomenon of great importance. Despite being appointed as the main cause of several pathologies, its effects are yet considered in a simplified way by the structural designers. In addition to studying the phenomenon in reinforced concrete structures and its current account used in the structural analysis, this paper compares creep strains at simply supported reinforced concrete beams in analytical and in experimental forms with the finite element method (FEM) simulation results. The strains and deflections obtained through the analytical form were calculated with the Brazilian code NBR 6118 (2014) recommendations and the simplified method from CEB-FIP 90 and the experimental results were extracted from tests available in the literature. Finite element simulations are performed using ANSYS Workbench software, using its 3D SOLID 186 elements and the structure symmetry. Analyzes of convergence using 2D PLANE 183 elements are held as well. At the end, it is concluded that FEM analyses are quantitative and qualitative efficient for the estimation of this non-linearity and that the method utilized to obtain the creep coefficients values is sufficiently accurate.

Étude du comportement des piles de pont confinées de PRFC par écoute acoustique

Une structure en béton armé est sujette à différents types de sollicitations. Les tremblements de terre font partie des événements exceptionnels qui induisent des sollicitations extrêmes aux ouvrages. Pour faire face à cette problématique, les codes de calcul des ponts routiers font appel à une approche basée sur des niveaux de performance qui sont rattachés à des états limites. Actuellement, les états limites d'une pile de ponts en béton armé (BA) confinée à l'aide de polymères renforcés de fibres de carbone (PRFC) proposés dans la littérature ne prennent pas en compte le confinement lié au chemisage de PRFC en combinaison avec celui des spirales d'acier. Ce projet de recherche était la suite du volet de contrôle non destructif d'une étude réalisée en 2012 qui comprenait un volet expérimental [Carvalho, 2012] et un volet numérique [Jean, 2012]. L'objectif principal était de compléter l'étude du comportement des poteaux en BA renforcés de PRFC soumis à un chargement cyclique avec les données acoustiques recueillies par St-Martin [2014]. Plus précisément, les objectifs spécifiques étaient de déterminer les états limites reliés aux niveaux de performance et de caractériser la signature acoustique de chaque état limite (p. ex. fissuration du béton, plastification de l'acier et rupture du PRFC). Une méthodologie d'analyse acoustique basée sur l'état de l'art de Behnia et al. [2014] a été utilisée pour quantifier la gravité, localiser et caractériser le type de dommages. Dans un premier temps, les données acoustiques provenant de poutres de 550 mm x 150 mm x 150 mm ont permis de caractériser la signature acoustique des états limites. Puis, des cinq spécimens d'essai construits en 2012, les données acoustiques de trois spécimens, soient des poteaux circulaires d'un diamètre de 305 mm et d'une hauteur de 2000 mm ont été utilisée pour déterminer les états limites. Lors de ces essais, les données acoustiques ont été recueillies avec 14 capteurs de résonances qui étaient reliés à un système multicanal et au logiciel AEwin SAMOS 5.23 de Physical Acoustics Corporation (PAC) [PAC, 2005] par St-Martin [2014]. Une analyse de la distribution des paramètres acoustiques (nbr. de comptes et énergie absolue) combiné à la localisation des événements et le regroupement statistique, communément appelé clustering, ont permis de déterminer les états limites et même, des signes précurseurs à l'atteinte de ces états limites (p. ex. l'initiation et la propagation des fissures, l'éclatement de l'enrobage, la fissuration parallèle aux fibres et l'éclatement du PRFC) qui sont rattachés aux niveaux de performances des poteaux conventionnels et confinés de PRFC. Cette étude a permis de caractériser la séquence d'endommagement d'un poteau en BA renforcé de PRFC tout en démontrant l'utilité de l'écoute acoustique pour évaluer l'endommagement interne des poteaux en temps réel. Ainsi, une meilleure connaissance des états limites est primordiale pour intégrer les PRFC dans la conception et la réhabilitation des ouvrages.

Investigação e avaliação da toxicidade aguda dos agrotóxicos mais utilizados no cinturão verde da Grande Natal (RN, Brasil) para o peixe-zebra (Danio rerio Hamilton Buchanan, 1822, Teleostei, Cyprinidae

The objectives of this research were to investigate the agrotoxic most used in the Gramorezinho region in the green belt of Natal, and to evaluate the acute toxicity of these, based on the LC50-48h values estimated in tests for Danio rerio, internationally used as test organism. The acute toxicity tests were performed under laboratory conditions, according to standardized methods (ABNT/NBR/15088/04) for this species. The LC50-48h estimated to Tamaron BR was 352.89 mg.L-1, which characterizes that as practically non-toxic, according to toxicological classes cited by Zucker. For Decis 25EC, the LC50-48h estimated was 0.0004156 mg.L-1 (4.156 X 10-4 mg.L-1), which classifies it as highly toxic to this species

Detecção e análise de áreas queimadas por meio da normalização de séries temporais MODIS na região do Jalapão

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Humanas, Departamento de Geografia, Programa de Pós-Graduação em Geografia, 2015.

¿Dónde estás, corazón? : es un merengue 5

Fondo Margaritainés Restrepo

Evolução da degradação de fachadas : efeito dos agentes de degradação e dos elementos constituintes

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2016.

Análise experimental do comportamento à flexão e ligação entre painéis de lajes tipo bubbledeck

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2016.

Aproveitamento de resíduos minerais na formulação de argamassas para a construção civil

Current environmental concerns include the excessive consumption and inefficient use of non-renewable natural resources. The construction industry is considered one of the largest consumers of natural raw materials, significantly contributing to the environmental degradation of the planet. The use of calcareous quarry (RPPC) and porcelain tile polishing residues (RPP) as partial replacements of the cement in mortars is an interesting alternative to minimize the exploration of considerably large amounts of natural resources. The present study aimed at investigating the properties of fresh and hardened mortars produced using residues to replace cement. The residues used were fully characterized to determine their specific mass, unitary mass, particle size distribution and morphology, and composition. The performance of the mortars was compared to that of reference compositions, prepared without residues. A total of 18 compositions were prepared, 16 using residues and 2 reference ones. The mortars were prepared using Portland CP II F 32 cement, CH I hydrated lime, river sand and tap water. The compositions of the mortars were 1:1:6 and 1:0.5:4.5 (vol%), and water to cement ratios of 1.87 and 1.45 were used, respectively. The mortars in the fresh state were evaluated by consistency index, water retention, density of mass and incorporated air content tests. In their hardened state, the mortars were evaluated by apparent mass density, modulus of elasticity, flexural tensile strength, compressive strength and water absorption by capillarity. The mortars were also analyzed by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and fluorescence. Finally, they were classified according to NBR 13281 standards. The mortars prepared using residues partially replacing the cement exhibited lower modulus of elasticity compared to the reference compositions, thus improving the performance in their intended use. On the downside, the water absorption by capillarity was affected by the presence of residues and both the tensile and compressive strength were reduced. However, from the overall standpoint, the replacement of cement by calcareous quarry or porcelain tile polishing residues did not result in significant changes in the properties of the mortars. Therefore, compositions containing these residues can be used in the construction industry