Selective Surface
Mostrando 13-24 de 800 artigos, teses e dissertações.
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13. Cationic flotation of smithsonite and dolomite from Brazilian Ambrósia Norte Deposit
Abstract The flotation of low-grade oxidized zinc ores has been commonly used to produce marketable concentrates for many years. Several flotation routes are being successfully used: cationic, anionic and a mixture of anionic and cationic. The choice of the route taken is dependent on the major zinc-bearing minerals in the deposit of interest and its associa
REM, Int. Eng. J.. Publicado em: 16/09/2019
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14. Double Layer Frequency Selective Surface for Ultra Wide Band Applications with Angular Stability and Polarization Independence
Abstract In this paper, a double layer stopband Frequency Selective Surface (FSS) for Ultra-Wide Band (UWB) applications is presented. The proposed FSS consists of two cascaded conventional FSS, one with double square loops and other with square loops. The − 10dB frequency band from 3.00 GHz to 11.64 GHz is achieved, with a fractional bandwidth of 149 %. E
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 12/09/2019
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15. Synthesis of Highly Ordered Mesoporous MCM-41: Selective External Functionalization by Time Control
Sol-gel synthesis is commonly used to modify the surface of mesoporous silica nanoparticles (MSN) with organic groups through the co-condensation method. The template removal, and the site-controlled addition of organic groups and their partial occlusion inside the framework walls are still a challenge in the one-pot synthesis. Here, we optimize the synthesi
J. Braz. Chem. Soc.. Publicado em: 12/08/2019
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16. Effects of Gas Nitriding on Fatigue and Crack Initiation of Ti6Al4V produced by Selective Laser Melting
Selective laser melting (SLM) is an additive manufacturing technique which permits fabrication of three dimensional parts by selectively melting consecutive layers of metallic powder. This allows the production of parts with high geometrical complexity. Titanium alloy Ti-6Al-4V (Ti64) is widely used in industry due to its high strength-to-mass ratio, corrosi
Mat. Res.. Publicado em: 15/07/2019
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17. A Novel Fractal Multi-band Frequency Selective Surface
Abstract In this paper, a new multiband fractal frequency selective surface (MF-FSS) is proposed. The work presents a new fractal design methodology for FSSs with Swastika fractal patch elements. The proposed MF-FSS includes periodic arrays of metallic patches, printed on a single layer substrate. The structure parametric analysis is carried out in terms of
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 19/06/2019
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18. Synthesis of New Reconfigurable Limited Size FSS Structures Using an Improved Hybrid Particle Swarm Optimization
Abstract This paper describes a new design methodology for reconfigurable printed circuits with limited size, using an improved hybrid particle swarm optimization (HPSO) algorithm, reducing the search space by the definition of negative zones (NZ), regions where the swarm of particles should not travel. The proposed design methodology (HPSO-NZ) is used in th
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 19/06/2019
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19. Characterization of new selective coatings, made of granite and chrome, for solar collectors
ABSTRACT The depletion of fossil fuel reserves and climate change caused by atmospheric pollution has led the human being to seek alternatives that are less damaging to the environment. The concern and the awareness of the population open space for the study of renewable energies to be deepened, among them the best use of solar energy. The use of alternative
Matéria (Rio J.). Publicado em: 10/06/2019
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20. Selecting chemicals for separation of ABS and HIPS in WEEE by froth flotation
Abstract The feasibility of using common chemicals to separate plastics from waste electrical and electronic equipment (WEEE) by froth flotation is investigated. Plastic waste is one of the WEEE polluters and a separation is necessary to recycle it. The most common plastics in electronic industries are acrylonitrile-butadiene-styrene (ABS) and high impact po
Polímeros. Publicado em: 10/06/2019
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21. Evaluation of Potential Residual Silica as Antireflective Layer for Selective Solar Surface of Black Chromium
Selective surfaces have the function of absorbing strongly the sunlight, while ideally losing little heat to the environment via convection and radiation. The present study sought to obtain a selective surface of black chromium coated with an antireflective (AR) layer based on sugarcane bagasse ash using copper as a substrate. From this selective surface the
Mat. Res.. Publicado em: 03/06/2019
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22. An eco-friendly method for extraction and quantification of flavonoids in Dysphania ambrosioides
ABSTRACT Dysphania ambrosioides (L.) Mosyakin and Clemants (Syn: Chenopodium ambrosioides L.), Amaranthaceae, is a plant with antibacterial, antifungal, antioxidant, antiparasitic and antitumor properties that is commonly used in Brazilian folk medicine. In this work we performed the optimization of ultrasound-assisted extraction of flavonoids in the aerial
Rev. bras. farmacogn.. Publicado em: 27/05/2019
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23. HPLC-PDA method validated for the determination of hibalactone in Hydrocotyle umbellata subterraneous parts and its ultrasound-assisted extraction optimization
ABSTRACT In this work, we developed and validated a HPLC-PDA method for the quantification of hibalactone in Hydrocotyle umbellata L., Araliaceae, subterraneous parts extracts and optimized its ultrasound-assisted extraction. Chromatographic separations were carried out with an isocratic mobile phase of acetonitrile/methanol/water (10:65:25), a flow of 0.8 m
Rev. bras. farmacogn.. Publicado em: 27/05/2019
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24. Gold Supported on Strontium Surface-Enriched CoFe2O4 Nanoparticles: a Strategy for the Selective Oxidation of Benzyl Alcohol
The synthesis of efficient and reusable gold-based catalysts for the selective oxidation of alcohols is a strategy for the development of green processes. Pre-formed nanoparticles syntheses are an easy way to produce controlled-nanosized gold materials; however, the selection of a support is not trivial. Herein, we proposed a CoFe2O4 support enriched with Sr
J. Braz. Chem. Soc.. Publicado em: 23/05/2019