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Search Results: 1 - 10 of 386130 matches for " L. C. Mendes "
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In Situ Hydroxyapatite Synthesis: Influence of Collagen on Its Structural and Morphological Characteristic  [PDF]
Luis C. Mendes, Geysy L. Ribeiro, Raphaella C. Marques
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.38083
Abstract: Hydroxyapatite (HA) was synthesized in situ by the precipitation method, with and without the presence of collagen (COLL), to study its influence on HA’s structural and morphological characteristics. The material was characterized by energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The Ca/P molar ratio was influenced by collagen addition—1.89 and 2.38 for samples without and with collagen, respectively. The WAXD pattern revealed better resolution and intensity besides higher crystallinity degree of the HA in the presence of collagen. The photomicrographs showed a strong influence of collagen on the HA morphology.
PET Oligomer Waste to Modify CAP Characteristics  [PDF]
L. C. Mendes, M. L. Dias, P. S. C. Pereira, L. M. R. Albuquerque
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.38082
Abstract: To develop an improved method of reusing poly(ethylene terephthalate) (PET) waste in the production chain, it was chemically modified with pentaerythritol (PENTE), resulting in PET/PENTE (60/40) oligomer. This was added to petroleum asphalt cement (CAP) in different proportions—5, 10 and 20 wt%—as a modifier of bitumen characteristics. The mixture was evaluated by thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), optical microscopy (OM) and the adhesion-peel test. The oligomer enhanced substantially the asphalt thermal stability-Tonset. OM images showed strong compatibility between components and PET’s amorphization. PET oligomer increased CAP’s wettability and the mixture presented cohesive fracture through the peel test. The mixture has excellent potential as paving material.
Conjecture on a classification criterion for holonomies for the U(1) group
Daniel de C. L. Mendes
Mathematics , 2005,
Abstract: Our main goal is to find a criterion to classify if a given group have a structure similar to a U(1) Lie group.
Regularities in football goal distributions
L. C. Malacarne,R. S. Mendes
Physics , 2000, DOI: 10.1016/S0378-4371(00)00363-0
Abstract: Besides of complexities concerning to football championships, it is identified some regularities in them. These regularities refer to goal distributions by goal-players and by games. In particular, the goal distribution by goal-players it well adjusted by the Zipf-Mandelbrot law, suggesting a conection with an anomalous decay.
Quantum Corrections for Generalized Partition Functions
L. R. Evangelista,L. C. Malacarne,R. S. Mendes
Physics , 1998, DOI: 10.1016/S0378-4371(97)00617-1
Abstract: The classical limit for generalized partition functions is obtained using coherent states. In this framework it is presented a general procedure to obtain all the corrections to the classical limit. In particular, the first and second order quantum corrections are worked out explicitly, and the classical limit for the Tsallis thermostatistics is determined. The results of this work generalize the ones obtained by E. Wigner (Phys. Rev. 40 (1932) 749) for usual statistical mechanics.
Two additions to the portuguese and iberian spider (Arachnida, Araneae) fauna
Crespo, L. C.,Mendes, S.,Prado e Castro, C.
Graellsia , 2010,
Abstract: Not available No disponible
Statistics of football dynamics
R. S. Mendes,L. C. Malacarne,C. Anteneodo
Physics , 2007, DOI: 10.1140/epjb/e2007-00177-4
Abstract: We investigate the dynamics of football matches. Our goal is to characterize statistically the temporal sequence of ball movements in this collective sport game, searching for traits of complex behavior. Data were collected over a variety of matches in South American, European and World championships throughout 2005 and 2006. We show that the statistics of ball touches presents power-law tails and can be described by $q$-gamma distributions. To explain such behavior we propose a model that provides information on the characteristics of football dynamics. Furthermore, we discuss the statistics of duration of out-of-play intervals, not directly related to the previous scenario.
Perturbation and Variational Methods in Nonextensive Tsallis Statistics
E. K. Lenzi,L. C. Malacarne,R. S. Mendes
Physics , 1998, DOI: 10.1103/PhysRevLett.80.218
Abstract: A unified presentation of the perturbation and variational methods for the generalized statistical mechanics based on Tsallis entropy is given here. In the case of the variational method, the Bogoliubov inequality is generalized in a very natural way following the Feynman proof for the usual statistical mechanics. The inequality turns out to be form-invariant with respect to the entropic index $q$. The method is illustrated with a simple example in classical mechanics. The formalisms developed here are expected to be useful in the discussion of nonextensive systems.
Average Entropy of a Subsystem from its Average Tsallis Entropy
L. C. Malacarne,R. S. Mendes,E. K. Lenzi
Physics , 2002, DOI: 10.1103/PhysRevE.65.046131
Abstract: In the nonextensive Tsallis scenario, Page's conjecture for the average entropy of a subsystem[Phys. Rev. Lett. {\bf 71}, 1291(1993)] as well as its demonstration are generalized, i.e., when a pure quantum system, whose Hilbert space dimension is $mn$, is considered, the average Tsallis entropy of an $m$-dimensional subsystem is obtained. This demonstration is expected to be useful to study systems where the usual entropy does not give satisfactory results.
q-exponential, Weibull, and q-Weibull distributions: an empirical analysis
S. Picoli Jr.,R. S. Mendes,L. C. Malacarne
Physics , 2003, DOI: 10.1016/S0378-4371(03)00071-2
Abstract: In a comparative study, the q-exponential and Weibull distributions are employed to investigate frequency distributions of basketball baskets, cyclone victims, brand-name drugs by retail sales, and highway length. In order to analyze the intermediate cases, a distribution, the q-Weibull one, which interpolates the q-exponential and Weibull ones, is introduced. It is verified that the basketball baskets distribution is well described by a q-exponential, whereas the cyclone victims and brand-name drugs by retail sales ones are better adjusted by a Weibull distribution. On the other hand, for highway length the q-exponential and Weibull distributions do not give satisfactory adjustment, being necessary to employ the q-Weibull distribution. Furthermore, the introduction of this interpolating distribution gives an illumination from the point of view of the stretched exponential against inverse power law (q-exponential with q > 1) controversy.
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