161 research outputs found

    A Remarkable Example of Bubble Nucleation Suppression

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    Suppression of cavitation is a relatively common goal of fluid engineers and therefore examples of bubble nucleation suppression in other technological contexts are useful in suggesting ways in which such suppression might be achieved. In this paper we describe a remarkable example of bubble nucleation suppression achieved by a combination of the elimination of nucleation sites and the reduction of bubble growth time. The context is the invention of a device that allows the injection of aqueous solutions highly supersaturated with oxygen into the bloodstream without the formation of significant gaseous oxygen bubbles

    Injection of Highly Supersaturated Oxygen Solutions without Nucleation

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    It is possible to inject highly supersaturated aqueous solutions of gas through a small capillary into an aqueous environment without the formation of significant gas bubbles. Such a technique has considerable potential therapeutic value in the treatment, for example, of heart attacks and strokes. The present paper is the second in a series (see Brereton et al. [1]) investigating the basic phenomenon behind this surprising effect. Recent experiments clearly demonstrate that the nucleation, when it does occur, results from heterogeneous nucleation on the interior surface of the distal end of the capillary. This paper describes the effects of the treatment of this interior surface on the nucleation processes and the results of high speed video observations of the phenomena. A heterogeneous nucleation model is presented which is in accord with the experimental observations

    Enxertia de maracujazeiro-amarelo (Passiflora edulis f. flavicarpa) em porta-enxertos oriundos de sementes de espécies de passifloras nativas.

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    Este trabalho teve como objetivo avaliar o desenvolvimento e a sobrevivência de copas de maracujazeiro-amarelo (Passiflora edulis f. flavicarpa Degener) enxertadas sobre dois porta-enxertos, oriundos de sementes de espécies de passifloras nativas. O experimento foi desenvolvido em casa de vegetal da Embrapa Mandioca e Fruticultura, no período de maio de 2012 a abril de 2013

    Caracterização morfoagronômica de diferentes copas de maracujazeiro enxertadas em porta-enxerto de Passiflora gibertii.

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    Este trabalho teve como objetivo caracterizar morfoagronomicamente diferentes copas de maracujazeiro enxertadas em porta-enxertos de Passiflora gibertii, com vistas à seleção de copas superiores. Foi utilizado um porta-enxerto com 25 copas diferentes, previamente obtidos do trabalho de pesquisa desenvolvido pela equipe de Recursos Genéticos da Embrapa Mandioca e Fruticultura

    Reconsiderando o efeito Fisher: uma análise de cointegração entre taxas de juros e inflação [Rethinking the Fisher Effect: a co-integration analysis between interest rates and inflation]

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    This paper investigates the validity of the Fisher effect hypothesis that it is the interest rate which moves to adjust to the anticipated changes in the rate of inflation. The analysis is carried out with monthly data for the period 1980-97 for three countries with recent histories of chronic high inflation: Argentina, Brazil, and Mexico. A co-integration analysis has provided evidence of a stable long-run equilibrium relationship between nominal interest rates and the inflation rate for the cases of Argentina and Brazil only.inflation, interest rate, monetary policy

    Analisador granulométrico automatizado aplicado na caracterização de pós de vidro processados por moagem.

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    O objetivo deste trabalho é a validação do analisador granulométrico na caracterização da evolução, em função do tempo, do tamanho de partículas de vidro obtidas por moagem.bitstream/CNPDIA/9713/1/CT27_98.pd

    Determinação da compatibilidade genética entre espécies de passifloras visando à obtenção de híbridos.

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    O presente trabalho teve como objetivo determinar os horários de antese e obter híbridos interespecíficos utilizando algumas espécies silvestres de maracujazeiro, visando à introdução de genes de resistência a doenças em germoplasma de maracujá. Para esta finalidade, dois genótipos de Passiflora edulis e dez espécies silvestres foram avaliados. O experimento foi realizado em casa de vegetação e em campo experimental da Embrapa Mandioca e Fruticultura, no período de agosto de 2012 a junho de 2013

    Infections in secondary immunodeficiency patients treated with Privigen® or Hizentra®: a retrospective US administrative claims study in patients with hematological malignancies

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    B cell-derived lymphoproliferative disorders are associated with secondary immunodeficiency (SID); some patients require immunoglobulin replacement therapy (IgRT) to mitigate infections. Using IQVIA’s PharMetrics® Plus database, patients with SID who received IgPro10/IgPro20 in the 12 months post-diagnosis (IgRT users) were matched to patients with SID not receiving IgRT (non-IgRT users). The risk of severe infection was compared using within-patient change from baseline to follow-up as well as between cohorts. Overall, 277 IgRT users were matched to 1019 non-IgRT users. Before IgRT, more IgRT users experienced any bacterial infection (88.4% vs. 72.9%; p<.0001) or ≥1 severe bacterial infection (SBI) (42.2% vs. 31.8%; p=.0011) vs. non-IgRT users. During follow-up, risk of SBI among IgRT users (21.7%) reached parity with non-IgRT users (21.2%). IgRT was associated with a reduction in SBIs to levels comparable with the lower ‘baseline infection risk’ of non-IgRT users. These criteria help define SID patients who may benefit from IgRT

    Lignocellulosic composites from brazilian giant bamboo (Guadua magna) Part 1: Properties of resin bonded particleboards

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    This experiment evaluated the utilization of the recently identified Brazilian giant bamboo, Guadua magna (Londoño &amp; Filg.) to manufacture medium density particleboard. Four board types were tested: two of them exclusively with particles of bamboo and two in a mixture of bamboo with Pinus taeda wood particles. The target density of the panels was 0.65 g/cm3 for all treatments. The particleboards were bonded using 8% content of urea-formaldehyde (UF) and phenol-formaldehyde (PF) resins, based on dry weight mat. Mechanical, physical and nondestructive properties of the panels were assessed. The particleboards produced with PF showed better dimensional stability than UF particleboards. The addition of wood particles improved the mechanical properties of EM, fM and IB. The flexural properties of the panels (EM, fM) could be modeled using either EMd or density and the models fitted presented high predictability (&gt;66%)

    Lignocellulosic composites from brazilian giant bamboo (Guadua magna). Part 2: Properties of cement and gypsum bonded particleboards

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    In the first part of this study, the feasibility of manufacturing resin-bonded particleboard from the recently identified Brazilian giant bamboo (Guadua magna) was evaluated. In this second part, the main goal was to study the material properties of the cement and gypsum-composites made from that bamboo species. The effect of CaCl2 addition in the physical and mechanical properties was also evaluated. Initially, the hydration test was performed to determine the inhibition index of the bamboo particles in the cement and gypsum setting. Three concentrations of CaCl2 were used to produce bamboo cementbonded particleboards (BCBP): 0%, 2% and 4%. CaCl2 was not added into bamboo gypsum-bonded particle boards (BGBP). Mechanical and physical properties were evaluated and nondestructive testing was performed as well. The inhibition index of Guadua magna in the cement or gypsum setting was classified as “low inhibition”. The addition of CaCl2 at bamboo-cement boards increased the internal &gt;bonding and reduced the water absorption. Other properties were not significantly affected. The bamboocement boards presented higher bending strength and lower moisture content than bamboo-gypsum boards
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