Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2020 ( 86 )

2019 ( 832 )

2018 ( 1009 )

2017 ( 1015 )

Custom range...

Search Results: 1 - 10 of 546689 matches for " M. L. Dias "
All listed articles are free for downloading (OA Articles)
Page 1 /546689
Display every page Item
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.
The fundamental group of $S^1$-manifolds
L. Godinho,M. E. Sousa-Dias
Mathematics , 2005,
Abstract: We address the problem of computing the fundamental group of a symplectic $S^1$-manifold for non-Hamiltonian actions on compact manifolds, and for Hamiltonian actions on non-compact manifolds with a proper moment map. We generalize known results for compact manifolds equipped with a Hamiltonian $S^1$-action. Several examples are presented to illustrate our main results.
Characterization of ZSM-5 modified with niobium pentoxide: the study of thiophene adsorption
Cavalcanti, Rodrigo M.;Barros, Ivoneide de C. L.;Dias, José A.;Dias, Sílvia C. L.;
Journal of the Brazilian Chemical Society , 2013, DOI: 10.1590/S0103-50532013000100007
Abstract: zsm-5 adsorbents impregnated with nb2o5 were applied in the sulfur removal in the form of thiophene, refractory substance of difficult removal of liquid fuels. for this purpose, a model fuel containing iso-octane contaminated with thiophene in concentrations of 877.5 to 1155 ppmw was prepared. the samples were characterized by x-ray diffractometry (xrd), fourier transform infrared (ftir) and fourier transform-raman (ft-raman) spectroscopies for confirmation of the adsorbents, being prioritized the adsorption study with that containing 5 wt.% of niobium pentoxide, because it showed a greater capacity for removal of thiophene. the best results of adsorption were achieved at 353 k, a longer time to reach equilibrium was observed. under these conditions, the best kinetic fitting was achieved using the equation of pseudo-second order, demonstrating the domain of the phenomenon of chemisorption. while under lower temperatures, the diffusion model presented a better approximation of the experimental results. also, the increasing of temperature did enhance spontaneous processes.
Emiss?es de queimadas em ecossistemas da América do Sul
Freitas, Saulo R.;Longo, Karla M.;Dias, M. A. F. Silva;Dias, P. L. Silva;
Estudos Avan?ados , 2005, DOI: 10.1590/S0103-40142005000100011
Abstract: the vegetation fires in tropical areas of the earth are important sources of pollutants to the atmosphere. in south america, during the winter months, an area, mainly of cerrado and forest ecosystems, of approximately 40 thousand square kilometers is burned annually. the biomass burning occurs primarily in amazon and central of brazil regions, but through atmospheric transport these emissions results in a spatial distribution of smoke over an extent area, of about 4-5 millions of square kilometers, much higher than the area where the fires are concentrated. during the combustion process are emitted to the atmosphere gases pollutants and aerosol particles that interact efficiently with radiation, microphysics process, dynamic of cloud formation and the air quality. the effects of these emissions exceed, therefore, the local scale and affect regionally the composition and physical and chemical properties of the south america atmosphere and neighborhood oceanic areas, with potential impact in a global scale.
Influencia de la interdisciplinaridad en las acciones del enfermero en Hemovigilancia
Dias,M.A.M.; Viana,L.O.;
Enfermería Global , 2012, DOI: 10.4321/S1695-61412012000100011
Abstract: this article comes from part of one of the chapters of analysis in a master's thesis in nursing whose subject is the training and skills of nurses in haemovigilance sentinel hospitals in rio de janeiro. this new perspective in health surveillance highlights nursing as the trigger for actions for specific research since the nurses are theprofessionals who witness most adverse events in their daily practice. the object of the study is the professional relations in haemovigilance and the it analyzes the everyday practice of nurses in the light if interdisciplinarity. the study concludes that the professional scope of the nurse has broadened and demands the respect and recognition of the nurse's actions on the part of other professionals in the new frontiers of health.
Efeito do grau de moenda na determina??o do teor total de mercúrio no solo
Dias,R. M. S.; Duarte,L.; Sempiterno,C. M.;
Revista de Ciências Agrárias , 2007,
Abstract: according to iso standard 11464 (soil quality - pre-treatment of samples for physico-chemical analyses) for test samples below 2 g, the air dried soil sample must be ground to a particle diameter ≤ 0.25 mm, in order to have a homogeneous test sample and, therefore, minimize the variability of results. this is quite a time consuming task. the aim of this study was to compare the influence of two different degrees of grinding (<2 mm and <0.15 mm) on the determination of total mercury, with test samples of 1 g. this element was analysed in 7 different soils from continental portugal, derived from different parent material. five representative samples were taken from each soil and manually crushed to pass a 2mm plastic sieve. each sample was then split in two portions: in one of them, mercury was analysed directly on the fine earth fraction (< 2 mm); on the other portion, mercury analysis was carried out only after grinding the soil sample on a agate mill till it just passed a plastic sieve of <0.15mm. mercury analysis consisted on the combustion of the soil sample and quantification by atomic absortion spectrometry on an advanced mercury analyser ama-254, at 253,65 nm. the influence of grinding was dependent on the type of soil, being significant (p≤0,05) in two of them, but even for those soils the levels of mercury are similar. grinding the soil to 0.15 mm did not increase significantly (p>0.05) the precision of results suggesting that, for the determination of total mercury with a test sample of 1 g, it is not necessary to grind the soil to a fraction less than 2 mm.
Efeito do grau de moenda na determina o do teor total de mercúrio no solo Influence of soil grinding degree on the determination of total mercury concentration
R. M. S. Dias,L. Duarte,C. M. Sempiterno
Revista de Ciências Agrárias , 2007,
Abstract: De acordo com a Norma ISO 11464 (Qualidade do solo - Pré-tratamento de amostras para análises físico-químicas) para tomas inferiores a 2 g, a terra seca deve ser moída até passar num peneiro de malha ≤ 0,25 mm, de modo a permitir que a homogeneidade da amostra seja tal que a variabilidade dos resultados seja minimizada. Esta tarefa é, no entanto, assaz morosa. Com o objectivo de avaliar o efeito da moenda no doseamento do mercúrio (Hg), em tomas de terra de cerca de 1 g, analisou-se este elemento em sete solos de Portugal Continental, derivados de diferentes materiais: (a) arenitos (podzol - Ap); (b) complexo derivado de xistos e “ra as” (solo mediterraneo vermelho - Sr+Vx); (c) dioritos ou gabros (barro preto n o calcário-Bp); (d) granitos (solo litólico húmico-Mng); (e) calcários (solo calcário pardo- -Pc); (f) aluvi es (aluviossolo moderno n o calcário - A) e (g) xistos (solo mediterraneo pardo - Px). De cada solo obtiveram-se cinco amostras representativas de terra seca ao ar, dividindo cada uma destas em duas frac es: numa a análise de Hg fez-se directamente na terra fina (<2 mm) e, na outra, fez-se na terra moída num moinho de ágata até que a amostra passasse completamente num peneiro de 0,15 mm de malha. A determina o do mercúrio foi efectuada por combust o da amostra seguida de quantifica o por espectrofotometria de absor o atómica num analisador de mercúrio AMA 254, a 253,65 nm. Os resultados obtidos revelam que o efeito médio da moenda sobre os valores de Hg dependeu das características do solo, sendo significativo (p≤0,05) apenas em dois deles mas, mesmo para esses solos, os valores de concentra o encontrados s o similares. De notar que a moenda fina (<0,15 mm) n o aumentou significativamente (p>0,05) a precis o dos resultados, sugerindo que na análise do teor total de mercúrio por este método é dispensável o passo da moenda fina das amostras. According to ISO Standard 11464 (Soil quality - Pre-treatment of samples for physico-chemical analyses) for test samples below 2 g, the air dried soil sample must be ground to a particle diameter ≤ 0.25 mm, in order to have a homogeneous test sample and, therefore, minimize the variability of results. This is quite a time consuming task. The aim of this study was to compare the influence of two different degrees of grinding (<2 mm and <0.15 mm) on the determination of total mercury, with test samples of 1 g. This element was analysed in 7 different soils from Continental Portugal, derived from different parent material. Five representative samples were taken from each soil and manually crushed to p
Regularity at infinity of real mappings and a Morse-Sard theorem
L. R. G. Dias,M. A. S. Ruas,M. Tibar
Mathematics , 2011, DOI: 10.1112/jtopol/jts005
Abstract: We prove a new Morse-Sard type theorem for the asymptotic critical values of semi-algebraic mappings and a new fibration theorem at infinity for $C^2$ mappings. We show the equivalence of three different types of regularity conditions which have been used in the literature in order to control the asymptotic behaviour of mappings. The central role of our picture is played by the $t$-regularity and its bridge toward the $\rho$-regularity which implies topological triviality at infinity.
Deafness and the Educational Rights: A Brief Review through a Brazilian Perspective  [PDF]
Lívia Dias, Ruth Mariani, Cristina M. C. Delou, Erika Winagraski, Helder S. Carvalho, Helena C. Castro
Creative Education (CE) , 2014, DOI: 10.4236/ce.2014.57058

In some countries, the human rights involving a proper education are still a privilege for just a few. In some of these regions, the right for a living with dignity and access to the current knowledge is considered a luxury, especially for people with special needs (e.g. deaf children) as the governmental systems still struggle to provide proper conditions to the regular ones. Herein we showed a brief review on deafness, its history on Brazilian education, the Brazilian sign language and the current need of deaf people for teaching resources at the scholar context to. We have also discussed facts that contributed to the Brazilian deaf education and alternative methodologies for the generation of educational resources that can maximize the teaching-learning process by stimulating the interest of deaf students for the science and biotechnological context. The inclusive educational practice with development of proper educational materials and methods may facilitate the teaching and learning process for everyone, including those with hearing loss. This inclusive practice is of great importance for achieving the educational improvement of all people in any society as a whole. Therefore, this article revisited themes that must be considered in the education of people with special hearing needs to guarantee their right of having a proper education and attention.

Silica-Based Nanocoating Doped by Layered Double Hydroxides to Enhance the Paperboard Barrier Properties  [PDF]
Vania M. Dias, Alena Kuznetsova, Jo?o Tedim, Aleksey A. Yaremchenko, Mikhail L. Zheludkevich, Inês Portugal, Dmitry V. Evtuguin
World Journal of Nano Science and Engineering (WJNSE) , 2015, DOI: 10.4236/wjnse.2015.54015
Abstract: Paperboard is an environment-friendly multi-layer material widely used for packaging applications. However, for food packaging paperboard lacks essential barrier properties towards oxygen and water vapor. Conventional solutions to enhance these barrier properties (e.g. paperboard film coating with synthetic polymers) require special manufacturing facilities and difficult the end-of-life disposal and recycling of the paperboard. Paperboard coating with silica-based formulations is an eco-friendly alternative hereby disclosed. Silica-nanocoatings were prepared by sol-gel synthesis, with or without the addition of Zn(2)-Al-NO3 layered double hydroxides (LDHs), and applied on the surface (ca 2 g/m2) of industrial paperboard samples by a roll-to-roll technique. The physicochemical features of silica-nanocoatings were studied by FTIR-ATR, SEM/EDS, XRD analysis and surface energy measurements. The barrier properties of uncoated and silica-coated paperboard were accessed by water vapor transmission rate (WVTR) and oxygen permeability (Jo2) measurements. The best barrier results were obtained for paperboard coated with a mixture of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES), with and without the incorporation of LDHs.
Page 1 /546689
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.