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Search Results: 1 - 10 of 156062 matches for " Ginetton F.;Albuquerque Jr "
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Prepara??o e caracteriza??o elétrica de sensores de metanol à base de nanocompósitos híbridos de polipirrol/nanopartículas metálicas
Oliveira, Helinando P. de;Oliveira, Ariadne H. P. de;Tavares, Ginetton F.;Albuquerque Jr, José J. F.;Andrade, César A. S.;
Polímeros , 2010, DOI: 10.1590/S0104-14282010005000042
Abstract: in this study, hybrid composites of gold nanoparticles and polypyrrole (aunps-ppy) were manufactured by chemical polymerization of the pyrrole monomer on the surface of metal nanoparticles, which were then incorporated in a poly(vinyl alcohol) (pva) matrix to be exploited in sensing technologies for detecting methanol. the preparation conditions were optimized to maximize sensitivity, allowing for the determination of relative concentrations of methanol molecules in binary mixtures of methanol/ethanol. this was carried out using the electrical response of the sensor, which depends on the dielectric constant of the volatile organic compounds.
Effects of the Energy Error Distribution of Fluorescence Telescopes on the UHECR energy spectrum
Carvalho Jr., Washington;Albuquerque, Ivone F. M.;de Souza, Vitor
High Energy Physics - Phenomenology , 2007, DOI: 10.1016/j.astropartphys.2007.04.010
Abstract: The measurement of the ultra high energy cosmic ray (UHECR) spectrum is strongly affected by uncertainties on the reconstructed energy. The determination of the presence or absence of the GZK cutoff and its position in the energy spectrum depends not only on high statistics but also on the shape of the energy error distribution. Here we determine the energy error distribution for fluorescence telescopes, based on a Monte Carlo simulation. The HiRes and Auger fluorescence telescopes are simulated in detail. We analyze the UHECR spectrum convolved with this energy error distribution. We compare this spectrum with one convolved with a lognormal error distribution as well as with a Gaussian error distribution. We show that the energy error distribution for fluorescence detectors can not be represented by these known distributions. We conclude that the convolved energy spectrum will be smeared but not enough to affect the GZK cutoff detection. This conclusion stands for both HiRes and Auger fluorescence telescopes. This result differs from the effect of the energy error distribution obtained with ground detectors and reinforces the importance of the fluorescence energy measurement. We also investigate the effect of possible fluorescence yield measurement errors in the energy spectrum.
Detection of Exotic Massive Hadrons in Ultra High Energy Cosmic Ray Telescopes
Ivone F. M. Albuquerque,Washington R. Carvalho Jr
Physics , 2009, DOI: 10.1103/PhysRevD.80.023006
Abstract: We investigate the detection of exotic massive strongly interacting hadrons (uhecrons) in ultra high energy cosmic ray telescopes. The conclusion is that experiments such as the Pierre Auger Observatory have the potential to detect these particles. It is shown that uhecron showers have clear distinctive features when compared to proton and nuclear showers. The simulation of uhecron air showers, and its detection and reconstruction by fluorescence telescopes is described. We determine basic cuts in observables that will separate uhecrons from the cosmic ray bulk, assuming this is composed by protons. If these are composed by heavier nucleus the separation will be much improved. We also discuss photon induced showers. The complementarity between uhecron detection in accelerator experiments is discussed.
Fragmenta??o mecanica de amêndoas de cupua?u (Theobroma grandiflorum)
Vilalba, Fábio de Albuquerque;Marsaioli Jr, Antonio;Pezoa Garcia, Nelson Horacio;
Ciência e Tecnologia de Alimentos , 2004, DOI: 10.1590/S0101-20612004000300021
Abstract: cupuassu (theobroma grandiflorum) is a native fruit from the brazilian amazon region whose seeds suitably fermented, dried and roasted can be used to manufacture a product similar to chocolate. this work aimed at devising an alternative way of cracking the dried but not roasted kernels by using a roller crusher, followed by using a set of sieves for separating the fractions. the variables studied for determining the nibs (scrapped cotyledons) acquisition yield as well the purity of such material (expressed as percent of shell and embryo fragments) were the moisture of the whole kernel and the differential speed of the double rollers of the crusher. the results confirmed that the moisture of the whole kernel was the variable that most influenced the cracking of kernels. the greater yield obtainment of nibs was reached at the 5% moisture level of the whole kernels. the variation of the double rollers differential speed did not present any significant difference as regards the nibs acquisition yield. as to the percent values of shell and embryo fragments, no studied variables have shown any significant difference on such a response values, even so the results were very well satisfactory, presenting values below the 1.75%. the yield of this alternative process is 90% of the cotyledons acquisition from certain kernels mass. as a conclusion, the process proposed herewith set oneself up as a mechanized alternative, showing good nibs acquirement yield, and percent of shells and embryo below the tolerated value.
Quantum percolation of one-electron states in power-law diluted chains
Silva Jr., M. P. da;Albuquerque, S. S.;Moura, F. A. B. F. de;Lyra, M. L.;
Brazilian Journal of Physics , 2008, DOI: 10.1590/S0103-97332008000100008
Abstract: we investigate the nature of one-electron eigenstates in power-law diluted chains for which the probability of occurrence of a bond between sites separated by a distance r decays as p(r) = 1/r1+s. using an exact diagonalization scheme on finite chains, we compute the spreading of an initially localized wave-packet, the time dependent participation number as well as the return probability. our results show the existence of a phase of extended states. by considering the scale invariance of the fluctuations of the participation number at the anderson transition, we obtained that extended states emerges for s < 0.68. this limiting value is larger than the one reported in the literature for the emergence of extended states in one-dimensional anderson models with power-law decaying couplings.
Desempenho e qualidade dos ovos de diferentes linhagens de poedeiras comerciais pós-muda for?ada recebendo ra??es com níveis variáveis de cálcio
ALBANO Jr., Milton;ALBUQUERQUE, Ricardo;LIMA, César Gon?alvez;GHION, Esleibe;LIMA, Félix Ribeiro;MORAIS, Cintra Suzane Dias;
Brazilian Journal of Veterinary Research and Animal Science , 2000, DOI: 10.1590/S1413-95962000000400015
Abstract: one experiment was conducted to study performance of laying hens of four strains after forced molt: lohmann white, babcok, embrapa-011 (light weight) and lohmann brown (semi-heavy weight). different levels of calcium were applied during the production period (2, 3, 4, 5 and 6%), the experimental design was a random block design with whole 400 birds. hens were 74 week old at the beginning of the molt phase. the birds fed 2% of calcium showed lower feed consumption and lower egg production. the highest levels of calcium increased the egg shell quality. the color of egg yolk was lower for levels 2 and 6% of calcium. egg weight, haugh unit and egg yolk color were related to strain, and the embrapa-011 showed the lower performance among strains.
Anterior hepatic transection for caudate lobectomy
Chaib, Eleazar;Ribeiro Jr, Marcelo A F;Souza, Yngrid Ellyn Dias Maciel de;D'Albuquerque, Luiz Augusto C;
Clinics , 2009, DOI: 10.1590/S1807-59322009001100013
Abstract: resection of the caudate lobe (segment i- dorsal sector, segment ix- right paracaval region, or both) is often technically difficult due to the lobe's location deep in the hepatic parenchyma and because it is adjacent to the major hepatic vessels (e.g., the left and middle hepatic veins). a literature search was conducted using ovid medline for the terms "caudate lobectomy" and "anterior hepatic transection" (aht) covering 1992 to 2007. aht was used in 110 caudate lobectomies that are discussed in this review. isolated caudate lobectomy was performed on 28 (25.4%) patients, with 11 case (11%) associated with hepatectomy, while 1 (0.9%) was associated with anterior segmentectomy. complete caudate lobectomy was performed on 82 (74.5%) patients. hepatocellular carcinoma was observed in 106 (96.3%) patients, while 1 (0.9%) had hemangioma and 3 (2.7%) had metastatic caudate tumors. aht was used in 108 (98.1%) caudate resections, while aht associated with a right-sided approach was performed in 2 (1.8%) cases. aht is recommended for tumors located in the paracaval portion of the caudate lobe (segment ix). aht is usually a safe and potentially curative surgical option.
Preparation, characterisation and evaluation of brazilian clay-based catalysts for use in esterification reactions
Rezende, Michelle J. C.;Pereira, Mírian S. C.;Santos, Gabriel F. N.;Aroeira, Gabriel O. P.;Albuquerque Jr., Tiago C.;Suarez, Paulo A. Z.;Pinto, Angelo C.;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012000700003
Abstract: natural brazilian clay-based catalysts were prepared, characterised, and their catalytic activity was assessed in esterification reactions. the natural clays were acid activated as received, without any previous treatment. both natural and acid-activated clays were characterised by xrd, nh3-tpd, thermodesorption of n-butylamine, n2 adsorption analysis, ft-ir, tga and dta. the catalytic performance was investigated in the esterification of several carboxylic acids with different alcohols. the reactions were carried out in a 1:3 carboxylic acid/alcohol molar ratio at 100 oc and atmospheric pressure for 3 h. the acid-activated clays provided good yields and better performance than commercial clay k10.
Potential application in biocatalysis of mycelium-bound lipases from Amazonian fungi
Zanotto, Sandra P.;Romano, Israel P.;Lisboa, Líliam U. S.;Duvoisin Jr., Sergio;Martins, Mayra K.;Lima, Fabiana A.;Silva, Soraya F.;Albuquerque, Patrícia M.;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000600008
Abstract: in this study, 212 fungi were isolated from amazon region plants, aiming to obtain mycelium bound-lipase-producing biocatalysts. these isolates were submitted to hydrolytic and synthetic activity assays. when submitted to the tributyrine substrate test, 87% of the isolates showed hydrolytic activity. of these, 30% showed good growth in lipase inducing liquid media and were submitted to evaluation of synthetic activity in esterification and transesterification reactions in organic solvents. the nine fungi which had the best synthetic activity were evaluated in the (r, s)-2-octanol resolution reaction, in order to verify the enantioselectivity of mycelium-bound lipases. the isolate uea_115 was the most versatile biocatalyst, showing good performance in esterification reactions (conversion > 90%) and good ability for the resolution of (r, s)-2-octanol (ees 29%; eep 99%; c 22%; e > 200). thus, this study has demonstrated the great potential of the amazonian fungi as lipase suppliers for biocatalysts.
F??bio Albuquerque
Problemata : International Journal of Philosophy , 2011, DOI: 10.7443/problemata.v2i2.11055
Abstract: This article consists of an approach about the existent relationship among two important themes in the heideggerian philosophy: the technique and the existential analytic of Dasein. The theme of the technique is focused in the concept of production, presented as the connection point among the two moments of the history of the technique: the te/xnh thematized for the Greeks and the modern technique. The theme of the existential analytic of Dasein, for your time, it is addressed for the temporality while ontological base of your existentiality. The two themes are approached starting from the subject concerning the implications that the structure of the process of production of the modern technique cause on the temporality of Dasein, influencing in the forms of manifestation of your ecstatical horizons. Este artigo consiste em uma abordagem sobre a rela o existente entre dois temas relevantes na filosofia heideggeriana: a técnica e a analítica existencial do Dasein. O tema da técnica é focado no conceito de produ o, apresentado como o ponto de liga o entre os dois momentos historiais da técnica: a τ -χνη tematizada pelos gregos e a técnica moderna. O tema da analítica existencial do Dasein, por sua vez, está direcionado para a temporalidade enquanto fundamento ontológico de sua existencialidade. Os dois temas s o abordados a partir da quest o das implica es que a estrutura do processo de produ o da técnica moderna causa sobre a temporalidade do Dasein, influenciando nas formas de manifesta o de seus horizontes ekstáticos.
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