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281.
Cleiton C. Silva Victor H.C. de Albuquerque Cícero R.O. Moura Willys M. Aguiar Jesualdo P. Farias 《Journal of Materials Engineering and Performance》2009,18(3):324-331
The present work evaluates the two-layer technique on the heat affected zone (HAZ) of AISI 4140 steel welded with different
heat input levels between the first and second layer. The weld heat input levels selected by the Higuchi test were 5/5, 5/10,
and 15/5 kJ/cm. The evaluation of the refining and/or tempering of the coarsened grain HAZ of the first layer was carried
out using metallographic tests, microhardness measurements, and the Charpy-V impact test. The tempering of the first layer
was only reached when the weld heat input ratio was 5/5 kJ/cm. The results of the Charpy-V impact test showed that the two-layer
technique was efficient, from the point of view of toughness, since the toughness values reached were greater than the base
metal for all weld heat input ratios applied. The results obtained indicate that the best performance of the two-layer deposition
technique was for the weld heat input ratio 5/5 kJ/cm employing low heat input. 相似文献
282.
Roberto Schaeffer Claude Cohen Anna Cecília J. de Aguiar Glaucio V. R. Faria 《Energy Efficiency》2009,2(2):165-178
Pressure is mounting in large Non-Annex 1 countries like Brazil, China, and India to accept binding commitments to reduce
their greenhouse gas emissions in the second, post-2012, commitment period. In the case of Brazil, pressure is higher for
the country to commit itself to reduce its emissions from land use changes but, because of the country’s recent high economic
growth rates, very soon, this pressure will also turn to reducing its greenhouse gas emissions from electricity production
and use in the various sectors of the economy. This paper summarizes the methodological approach, and the results, of a study
aimed at assessing the potential for electricity conservation and carbon dioxide emissions reductions in the Brazilian household
sector. The study splits the household sector into 20 subsectors, considering five different geographical regions and four
household electricity consumption levels (a proxy for different household income levels). Technical, economic, and market
potentials are determined for electricity conservation in these 20 subsectors for the period 2005–2030, and results are also
translated into carbon dioxide emission reductions using the Clean Development Mechanism (CDM) combined margin (build margin
plus operating margin) approach for determining the emission’s factor for the power grids. Results show significant electricity
and carbon dioxide reduction potentials at negative costs for both household final consumers (market potential) and the economy
as a whole (economic potential) in the residential sector of Brazil.
相似文献
Glaucio V. R. FariaEmail: |
283.
Ana Gomes Luísa Aguiar Ricardo Ferraz Ctia Teixeira Paula Gomes 《International journal of molecular sciences》2021,22(21)
Topical and transdermal delivery systems are of undeniable significance and ubiquity in healthcare, to facilitate the delivery of active pharmaceutical ingredients, respectively, onto or across the skin to enter systemic circulation. From ancient ointments and potions to modern micro/nanotechnological devices, a variety of approaches has been explored over the ages to improve the skin permeation of diverse medicines and cosmetics. Amongst the latest investigational dermal permeation enhancers, ionic liquids have been gaining momentum, and recent years have been prolific in this regard. As such, this review offers an outline of current methods for enhancing percutaneous permeation, highlighting selected reports where ionic liquid-based approaches have been investigated for this purpose. Future perspectives on use of ionic liquids for topical delivery of bioactive peptides are also presented. 相似文献
284.
Neusa L. Figueiredo Sara Raquel M.M. de Aguiar Pedro Luis Falé Lia Ascensão Maria Luisa M. Serralheiro Ana Rosa L. Lino 《Food chemistry》2010
Aqueous extracts of Plectranthus barbatus and Plectranthus ecklonii are traditionally used as anti-inflammatory and anti-fungal agents. The effect of these extracts and of its main component, rosmarinic acid, on the viability of the cariogenic bacteria, Streptococcus sobrinus and Streptococcus mutans, was determined by MIC and MBC. The influence of these extracts on the biofilm formation as well as on the inhibition of glucosyltransferase enzyme, produced by these species, was also analysed. Aqueous extracts of P. barbatus and P. ecklonii were stronger inhibitors than rosmarinic acid. MIC values of 3.8 and 4.7 mg/ml for S. sobrinus and 2.9 and 5.0 for S. mutans were obtained, while rosmarinic acid presented MIC values of 8.4 and 7.3 mg/ml. P. barbartus, P. ecklonii and rosmarinic acid presented MBC values of 9.5, 9.0 and 12.0 mg/ml for S. sobrinus, and 9.5, 10.0 and 12.5 mg/ml for S. mutans. The inhibition of biofilm formation by P. barbatus, P. ecklonii and rosmarinic acid presented IC50 values of, respectively, 0.6, 1.0 and 3.1 mg/ml for S. sobrinus and 1.4 and 2.7 and 1.3 mg/ml for S. mutans. The glucosyltransferase inhibition activity by theses extracts and rosmarinic acid was calculated and IC50 values presented were, respectively, 1.1, ca 1.2 and 2.1 mg/ml for S. sobrinus and 3.1, 1.6 and 3.9 mg/ml for S. mutans were obtained. These extracts may be useful in the prevention of dental carie. 相似文献
285.
Anna Lecticia Martinez Martinez Toledo Elton Jorge da Rocha Rodrigues José Carlos Dutra Filho Domethila Mariano de Souza Aguiar dos Santos Suelen Adriani Marques Maria Inês Bruno Tavares 《Polymer Engineering and Science》2020,60(4):673-681
Sol–gel-based zirconia (ZrO2) and silica (SiO2) were obtained in situ via hydrolysis–polycondensation of metal alkoxide precursors in membranes of poly(3-hydroxybutyrate) (PHB). What followed was an assessment of thermal and spectroscopic effects from the insertion of the inorganic network in the PHB matrix. The findings exhibited a dependence of both the concentration and the chemical nature of the precursor on the properties of the as-formed inorganic–organic hybrids. The results also indicated that positive nucleating effects, a reduction of the crystallite size and a variation in thermal transitions correlate with spectroscopic data from the alpha and beta crystal forms of the PHB matrix, as well as the crystallization data obtained through polarized light microscopy. POLYM. ENG. SCI., 60:673–681, 2020. © 2020 Society of Plastics Engineers 相似文献
286.
This paper presents the surface-based factorization method to recover three-dimensional (3-D) structure, i.e., the 3-D shape and 3-D motion, of a rigid object from a two-dimensional (2-D) video sequence. The main ingredients of our approach are as follows: 1) we describe the unknown shape of the 3-D rigid object by polynomial patches; 2) projections of these patches in the image plane move according to parametric 2-D motion models; 3) we recover the parameters describing the 3-D shape and 3-D motion from the 2-D motion parameters by factorizing a matrix that is rank 1 in a noiseless situation. Our method is simultaneously an extension and a simplification of the original factorization method of Tomasi and Kanade (1992). We track regions where the 2-D motion in the image plane is described by a single set of parameters, avoiding the need to track a large number of pointwise features, in general, a difficult task. Then our method estimates the parameters describing the 3-D structure by factoring a rank 1 matrix, not rank 3 as in Tomasi and Kanade. This allows the use of fast iterative algorithms to compute the 3-D structure that best fits the data. Experimental results with real-life video sequences illustrate the good performance of our approach 相似文献
287.
288.
This paper addresses the stabilization of a class of nonlinear systems in the presence of disturbances, using switching controllers. To this effect we introduce two new classes of switched systems and provide conditions under which they are input-to-state practically stable (ISpS). By exploiting these results, a methodology for control systems design—called switched seesaw control—is obtained that allows for the development of nonlinear control laws yielding input-to-state stability. The range of applicability and the efficacy of the methodology proposed are illustrated via two nontrivial design examples. Namely, stabilization of the extended nonholonomic double integrator (ENDI) and stabilization of an underactuated autonomous underwater vehicle (AUV) in the presence of input disturbances and measurement noise. 相似文献
289.
290.
Graziele G. Bovi Oluwafemi J. Caleb Cornelia Rauh Pramod V. Mahajan 《Packaging Technology and Science》2019,32(11):545-554
Disruption in cold chain during distribution and retail could have a significant impact on in‐package condensation of optimally designed packaged fresh produce. The aim of this work was to regulate in‐package condensation and evaluate the performance of different packaging design systems for strawberries under fluctuating temperatures (between 10°C and 20°C) for 5 days. The design included the use of condensation control strategies, namely, enhanced permeable films (NatureFlex and Xtend) and FruitPad of different fructose content (0%, 20%, 30%, 35%, and 40%). Package performance was evaluated in terms of headspace gas composition, mass loss, condensation, physico‐chemical changes, and visual and ortho‐nasal quality evaluation. Percentage mass loss of packaged strawberries ranged from 0.6% to 4% and was 33% for unpackaged. Results also showed that compared with the control sample, both strategies (enhanced permeable films and FruitPads) were effective in reducing condensation. In addition, transpirational water loss, results of the water absorbed by the FruitPads and transferred through the films were used to understand the packaging design needs under fluctuating temperature. 相似文献