Contact angle of a hemispherical bubble: an analytical approach

We have calculated the equilibrium shape of the axially symmetric Plateau border along which a spherical bubble contacts a flat wall, by analytically integrating Laplace’s equation in the presence of gravity, in the limit of small Plateau border sizes. This method has the advantage that it provides closed-form expressions for the positions and orientations of the Plateau border surfaces. Results are in very good overall agreement with those obtained from a numerical solution procedure, and are consistent with experimental data. In particular we find that the effect of gravity on Plateau border shape is relatively small for typical bubble sizes, leading to a widening of the Plateau border for sessile bubbles and to a narrowing for pendant bubbles. The contact angle of the bubble is found to depend even more weakly on gravity

Controle da produção leiteira e a demanda por sistemas computacionais simples.

A indústria de software agropecuário trabalha para colaborar com a administração de propriedades rurais procurando compatibilizar complexidade do controle de indicadores e produzir uma ferramenta que seja útil para produtores e técnicos. Esta busca é ajustada pela observação do tamanho do mercado usuário ou potencial usuário de software agropecuários. O artigo tem por objetivo apresentar a necessidade de oferta de ferramentas computacionais simples para o controle da produção de leite visando facilitar a gestão do negócio da pecuária leiteira. Para tanto, foi avaliada estratificação de produtores de leite combinados com dados de quem controla dados de suas propriedades e com reunião com especialistas em agroinformática ocorridas em 2008. Como resultado considerou-se que o uso de planilha eletrônica seria o recomendada na fase inicial de controles passando para programas/software mais detalhados à medida que o registro e uso dos dados como informação seja praticado.SBIAgro 2009

When is a surface foam-phobic or foam-philic?

By integrating the Young-Laplace equation, including the effects of gravity, we have calculated the equilibrium shape of the two-dimensional Plateau borders along which a vertical soap film contacts two flat, horizontal solid substrates of given wettability. We show that the Plateau borders, where most of a foam's liquid resides, can only exist if the values of the Bond number ${\rm Bo}$ and of the liquid contact angle $\theta_c$ lie within certain domains in $(\theta_c,{\rm Bo})$ space: under these conditions the substrate is foam-philic. For values outside these domains, the substrate cannot support a soap film and is foam-phobic. In other words, on a substrate of a given wettability, only Plateau borders of a certain range of sizes can form. For given $(\theta_c,{\rm Bo})$, the top Plateau border can never have greater width or cross-sectional area than the bottom one. Moreover, the top Plateau border cannot exist in a steady state for contact angles above 90$^\circ$. Our conclusions are validated by comparison with both experimental and numerical (Surface Evolver) data. We conjecture that these results will hold, with slight modifications, for non-planar soap films and bubbles. Our results are also relevant to the motion of bubbles and foams in channels, where the friction force of the substrate on the Plateau borders plays an important role.Comment: 20 pages, 14 figure

Betalains and phenolic compounds of leaves and stems of Alternanthera brasiliana and Alternanthera tenella

Betacyanins and phenolic compounds from acetonitrile:acidified water extracts of Alternanthera brasiliana and Alternanthera tenella were characterized and quantified using a high-performance liquid chromatography system coupled with diode array and electrospray mass spectrometry detection. Four betacyanins (amaranthine, isoamaranthine, betanin and isobetanin) were tentatively identified and quantified. Twenty eight phenolic compounds of four different families (hydroxybenzoic and hydroxycinnamic acids, flavones and flavonols) were separated and characterized on the basis of their accurate MS and MS/MS information out of which ten compounds were confirmed by authentic standards. These plant species could be considered as an especially rich source of natural bioactive compounds and potential food colorants. A. brasiliana showed the highest betacyanin and polyphenols content (89 μg/g and 35,243 μg/g, respectively). Among polyphenols, flavonols were the more abundant (kaempferol-glucoside, kaempferol-rutinoside and kaempferol-rhamnosyl-rhamnosyl-glycoside). Meanwhile, A. tenella showed a different polyphenols profile with flavones as major compounds (glucopyranosil-vitexin and vitexin). As a novelty, pentosyl-vitexin and pentosyl-isovitexin were detected for the first time in Alternanthera plants. Both A. brasiliana and A. tenella leaves showed high total polyphenol content and in vitro antioxidant activity (FRAP). These results provide an analytical base concerning the phenolic and betalains composition and the antioxidant properties of two members of the promising Alternanthera gender, for subsequent applications, such as functional food ingredients.Fil: Deladino, Lorena. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Alvarez, I.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: De Ancos, B.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Sánchez Moreno, C.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Molina García, A. D.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Schneider Teixeira, Aline. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; Españ

Ultrasonic estimates of fat thickness and longissimus dorsi muscle depth for predicting carcass composition of live Aragon lambs

Six ultrasonic fat and muscle depth measurements, taken on the left and the right side of the fourth lumbar vertebra and third stemebra of the breast bone, were related to carcass composition to determine the accuracy of these measurements for predicting carcass compositon of live Aragdn lambs (Temasco) . Live weight alone accounted for 21, 19,26, 18 and 47% of total variation of muscle, bone plus remainder, total fat, and subcutaneous and intermuscular fat, respectively. Addition of ultrasonic fat depth measurement on the right side of the lumbar region accounted for a further 18,31,33 and 36% of muscle, bone plus remainder, total carcass fat and subcutaneous fat, respectively. Addition of the same measurement taken on the left side accounted for a further 15% of intermuscular fat. Live weight alone accounted for only 4% of the total variation of kidney and pelvic fat, but the addition of ultrasonic fat depth measurement on breast bone accounted for a further 26% of the variation of this fat depot. The accuracy of prediction of carcass composition on live animals could be improved by the addition of ultrasonic fat measurements.Un total de 6 mesures d'épaisseur du gras et du muscle, réalisées en utilisant des ultrasons sur la 4ème vertèbre lombaire et la 3ème sternèbre sternale, ont été rapportées à la composition de la carcasse, en ayant comme objetif d'étudier l'exactitude de ces mesures en tant qu'élément de prédiction de la composition de la carcasse d'agneaux vivants producteurs du ‘Ternasco d'Aragón’. Le poids vif à lui seul a expliqué 21, 19, 26, 18 et 47% de la variation totale du muscle, de l'os plus les déchets, du gras total et du gras souscutané et intermusculaire, respectivement. L'addition des mesures d'épaisseur du gras (mesure C) réalisées par ultrasons sur le côté droit de la région lombaire, ont augmenté de 18, 31, 33 et 36% la précision de l'estimation de la variation totale du muscle, de l'os plus déchets, du gras total et sous-coutané de la carcasse, respectivement. L'addition de la même mesure réalisée sur le côté gauche a augmenté de 15% la précision de l'estimation de la variation totale du gras intermusculaire. Cependant, le poids vif n'a expliqué que 4% de la variation totale du gras pelvico-rénal, mais l'addition de la mesure d'épaisseur du gras sternal total, réalisée aux ultrasons, a augmenté de 26% la précision de l'estimation de la variation de ce dépôt adipeux. La précision de la prédiction de la composition de la carcasse sur l'animal vivant pourrait augmenter par l'addition de mesures de l'épaisseur du gras réalisées aux ultrasons.Un total de 6 medidas de espesor de grasa y músculo realizadas mediante la utilización de ultrasonidos sobre la 4a vertebra lumbar y la 3a esternebra del esternón fueron relacionadas con la composición de la canal, con el principal objetivo de estudiar la exactitud de estas medidas como predictoras de la composición de la canal de corderos vivos productores de ‘Ternasco de Aragón’. El peso vivo solo explicó el 21, 19, 26, 18 y 47% de la variación total del músculo, hueso más desechos, grasa total y grasa subcutanea e intermuscular respectivamente. La adición de las medidas de espesor de grasa (medida C) realizadas con ultrasonidos sobre el lado derecho de la región lumbar, incrementaron un 18, 31, 33 y 36% la precisión de la estimacón de la variación total del músculo, hueso más desechos, grasa total y subcutánea de la canal respectivamente. Y la adición de la misma medida realizada sobre el lado izquierdo incrementó un 15% la precisión en la estimación de la variación total de grasa intermuscular. Sin embargo el peso vivo solo explicó el 4% de la variación total de grasa pelvico-renal, pero la adición de la medida de espesor de grasa total del esternón realizada con untrasonidos, incrementó un 26% la precisión de la estimación de la variación de este depósito adiposo. La precisión de la predicción de la composición de la canal en el animal vivo podría ser incrementada con la adición de medidas del espesor de grasa realizadas con ultrasonidos

Proton conductivity of Nafion-azolebisphosphonates membranes for PEM fuel cells

Energy systems with cleaner and sustainable sources are crucial challenges of the 21st century to deal with the environmental threat of global warming and the declining reserves of fossil fuels. Fuel cells are electrochemical devices that convert the chemical energy stored in a fuel directly into electrical energy, providing electrical energy with high efficiency and low environmental impact. Among them, proton exchange membrane fuel cells (PEMFCs) are considered promising power sources, due to their high power density and high power-to-weight ratio but their performance depends crucially on their proton exchange membranes [1]. Usually, these membranes are made of organic polymers containing acidic functionalities (ex. Nafion® ), which proton transport properties strongly depend on their water content and, consequently, limit their operation temperatures up to 90ºC. Preliminary studies have demonstrated that incorporation of aryl-bisphosphonic acids into Nafion, by casting, results in an enhancement of the proton conductivity of the membrane. The aim of this work was the preparation of new Nafion membranes doped with azolebisphosphonates derivatives, which could act as a source of protons and also function as proton acceptors, facilitating the intermolecular transmission of protons through the membrane

Deliriumin the ICU setting ‐ a subjective and theoretical survey before the implementation of the Confusion Assessment Method for the ICU in an unit

Background and Goal of Study: The current definition of delirium comprises acute change or fluctuation in mental status and inattention, accompanied by either altered level of consciousness or disorganized thinking. It is a frequent condition in the ICU and it is associated with longer hospital stay, increase in mortality at 6 months and long-term cognitive impairment, but remains under diagnosed. The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) has been validated and implemented in many ICUs and its use is recommended by the Society of Critical Care Medicine. It is our purpose to evaluate the individual perspective and the objective knowledge of our staf f about delirium before the implementation of the CAM-ICU. Materials and Methods: Anonymous survey to our ICU clinical staf f which contained subjective and ‘true or false’ questions. Data was analised with the sof tware SPSS version 17.0. The Wilcoxon test was used to compare autoperception of knowledge about delirium and the content of answers regarding its definiton. Results: Forty two questionnaires were returned (participation rate of 73%), 11 from physicians and 31 from nurses. Overall, 61,9% of inquiries think they can give a definition for delirium in the ICU and 50% claim to be able to evaluate delirium. 28,6% of the respondents - 63,6% of the physicians and 16,1% of the nurses - know the CAM-ICU. From these only a quarter has received education on this method, 75% think it’s easy to apply and 66% don’t see its use as an increase in the daily workload. We found a high rate of wrong and ‘I don’t know’ answers to questions about operationalization, diagnosis and outcome. The subjects’ auto-perception on their knowledge about delirium [Likert scale] was compared to their ability to answer questions related to its definiton - ‘attention deficit is essencial for diagnosis’ [true], Wilcoxon test Z=-4,699 (p< 0,001); ‘disorganized thinking is essential for diagnosis’ [false], Wilcoxon test Z=-4,437 (p< 0,001). Conclusions: The respondents’ auto perception of knowledge about delirium doesn’t translate in the ability of giving an appropriate definition and making an adequate evaluation. Most of the inquiries don’t know the CAM-ICU, but those who do believe it’s easy to apply and its use won’t increase the workload. We performed educational sessions about delirium and the CAM-ICU in our unit to encourage our clinical staf f to deal properly with this hazardous condition

Bidirectional Ventricular Tachycardia Due to Hypokalaemia

info:eu-repo/semantics/publishedVersio