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materials science and Technology 2018, MS and T 2018

作者： Andrade, Malena Aissa De Oliveira, Bráulio Salumão Milanez, Douglas Henrique Leiva, Daniel Rodrigo Zepon, Guilherme Materials Engineering Department Federal University of São Carlos Rodovia Washington Luis km 235 São Carlos. São Paulo State Brazil Center for Technological Information in Materials Federal University of São Carlos Rodovia Washington Luis km 235 São Carlos. São Paulo State Brazil Postgraduate Program in Materials Science and Engineering Federal University of São Carlos Rodovia Washington Luis km 235 São Carlos. São Paulo State Brazil

ISBN: (纸本)0873397681

Low-density steels are studied aiming to increase the specific strength and consequently decrease automobile weight. Scientific and technological indicators can be elaborated based on information contained in articles and patent documents and assists to detect trends in emerging topics. This study evaluated recent developments in low-density steel alloys through bibliometric techniques. The results show Japan, South Korea, China, Germany and USA as the main players. Ductility and corrosion resistance figures as important technological challenges apart from strengthening. Beyond aluminum, manganese and carbon - mainly used for density reduction - silicon and chromium stand out as the main alloying elements studied for stacking fault energy control. The indicators suggest that new technologies and its insights shall be expected and monitored in near future, mainly for supporting material selection and R&D decision makings. Copyright © 2018 MS&T18®

关键词： Corrosion resistance

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Incorporation of Oregano Essential Oil Microcapsules in Starch-Poly (Butylene Adipate Co-Terephthalate) (PBAT) Films

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Macromolecular Symposia 2019年第1期383卷

作者： de Medeiros, João Augusto Salviano Blick, Ana Paula Galindo, Marcella V. Alvim, Izabela D. Yamashita, Fabio Ueno, Cláudio Takeo Shirai, Marianne Ayumi Grosso, Carlos Raimundo Ferreira Corradini, Elisângela Sakanaka, Lyssa Setsuko Federal University of Technology of Paraná − Department of Materials Engineering LondrinaParana Brazil Londrina State University − Department of Food Science and Technology Londrina Parana Brazil Federal University of Technology of Paraná − Department of Food Technology LondrinaParana Brazil Institute of Food Technology − Bakery and Confectionary Technology Center LondrinaParana Brazil Federal University of Technology of Paraná − Postgraduate Program in Food Technology LondrinaParana Brazil Federal University of Technology of Paraná − Postgraduate Program in Materials Science and Engineering LondrinaParana Brazil

Summary Cassava starch and poly(butylene adipate-co-terephthalate) (PBAT) based films containing microencapsulated oregano essential oil (OEO) and free OEO are produced by blow extrusion. Microcapsules produced by ionic gelation were characterized with respect to average size, morphology, and encapsulation efficiency. The microcapsules were spherical and ranged in size from 20 to 1000 μm. Encapsulation efficiency (EE) is 83%. The films are analyzed in terms of their morphology, mechanical properties, water vapor permeability (WVP) and antibacterial properties. The films containing OEO microcapsules exhibited lower ultimate tensile strength, Young's modulus and elongation at break than the control films and the films containing free OEO. The WVP of films containing free OEO is slightly lower, while that of films containing microencapsulated OEO did not differ significantly from the control films. Scanning electron microscopy (SEM) images showed that the surface of films containing microencapsulated OEO are less homogeneous than those of the control and free OEO films. Films containing free or microencapsulated OEO presented inhibitory activity against Staphylococcus aureus, but not against Escherichia coli. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

关键词： Elastic moduli

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Fabrication of organo-silica thin film for water desalination from dual silicate precursor (tetraethylorthosilicate & methyltriethoxysilane)

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AIP Conference Proceedings 2023年第1期2682卷

作者： Dewi Puspita Sari Muthia Elma Mahmud Mahmud Basir Basir Mita Riani Rezki Rahmawati Rahmawati Lilis Septyaningrum Gesit Satriaji Saputro Aulia Rahma 1Natural Resource and Environmental Management Department Pascasarjana Lambung Mangkurat University Jl. A. Yani KM 36 Banjarbaru 70714 Indonesia 2Chemical Engineering Department Faculty of Engineering Lambung Mangkurat University Jl. A. Yani KM 36 Banjarbaru 70714 Indonesia 4Wetland-Based Materials Research Center Lambung Mangkurat University Banjarbaru 70714 Indonesia 5Environmental Science Department Postgraduate Program Lambung Mangkurat University Jl. Brigjen H. Hasan Basri Kayu Tangi Banjarmasin 70123 Indonesia 3Environmental Engineering Department Faculty of Engineering Lambung Mangkurat University Jl. A. Yani KM 36 Banjarbaru 70714 Indonesia

A modification of silica structure is urgently needed to improve silica-based matrices applied for water desalination. It is due to the hydrophilic properties owned by pure silica structures, and it is also caused by the silica pore was collapse during ions water exposed on membrane surfaces. According to that, this study is aimed to fabricate and to observe the innovation of silica membranes modified matrices by mixing the main precursor of tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as sources of silicate as well as carbon applied for water desalination. The mixtures of MTES:TEOS (10:90) was mixed with acid-base catalysts using sol gel method. This process and reaction were held for 3 h nonstop. The modified organo-silica sols were dried by oven for 24 h and grinded into powder that called xerogel. Then it was calcined using furnace for 1 h at 350 and 450 °C using RTP (rapid thermal processing) method which under variation of condition (vacuum and air/atmosphere). Functionalization of modified organo-silica membranes were investigated using FTIR spectra and Fityk software. The results show the modified organo-silica derived from MTES (as a carbon source) exhibited the functionalization of siloxane (Si-O-Si), silanol (Si-OH), and silica-carbon (Si-C) functional groups. The optimum organo-silica MTES:TEOS mixture was obtained from sample calcined at 450 °C under vacuum calcination. The presence of carbon bonds causes the pores formed tend to be small but strong so it is suitable for application in the desalination process.

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Novel carbon templated silica membrane prepared from Nypa fruticans leaf for seawater desalination

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AIP Conference Proceedings 2023年第1期2682卷

作者： Elsa Nadia Pratiwi Muthia Elma Mahmud Mahmud Basir Basir Mita Riani Rezki Era Nandita Radiya Oktaviana Siti Fatimah Gesit Satriaji Saputro Erdina Lulu Atika Rampun Aulia Rahma 1Natural Resource and Environmental Management Department Pascasarjana Lambung Mangkurat University Jl. A. Yani KM 36 Banjarbaru 70714 Indonesia 2Chemical Engineering Department Faculty of Engineering Lambung Mangkurat University Jl. A. Yani KM 36 Banjarbaru 70714 Indonesia 4Wetland-Based Materials Research Center Lambung Mangkurat University Banjarbaru 70714 Indonesia 5Environmental Science Department Postgraduate Program Lambung Mangkurat University Jl. Brigjen H. Hasan Basri Kayu Tangi Banjarmasin 70123 Indonesia 3Environmental Engineering Department Faculty of Engineering Lambung Mangkurat University Jl. A. Yani KM 36 Banjarbaru 70714 Indonesia

Inorganic material applied for membrane technology such as silica is well employed for water desalination nowadays. Silica membrane is favorable to use to offer high selectivity and robust materials. However, it also has a debility due to unstable matrices when contact to water. Nypa fruticans leaf was fundamentally containing carbon which is potential as templating agent to enhanced the hydro-stability. The objective of this work is to investigate performance of nypa-silica membrane for desalination of seawater. Nypa-silica membrane prepared by mixing silica sol and carbon from nypa (0.1, 0.5 and 2.5 %) for 90 min at cold temperature. Then membrane support was immersed into nypa-silica sol by dipcoater and calcined at 350 and 450°C under inert atmosphere condition via rapid thermal processing (RTP) technique. Silica-nypa membranes were tested by seawater desalination (3.5 wt% NaCl) by pervaporation. Carbon from nypa gave a good impact to silica base membrane performance depends on template loading. Increasing concentration of nypa may reduce water flux of permeate. The result of membrane in this work rather low water flux. However, all of membranes show great salt rejection >99.9%. Interestingly, the permeate salt concentration of all silica-nypa membranes performed less than 600 ppm of limited total dissolved salt on drinking water according to standards given by the World Health Organization (WHO).

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Parameter processes and their impact on Tinospora cordifolia stem extracts for antibacterial and antioxidant materials

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materials Today: Proceedings 2023年

作者： Ahmad Royani Muhammad Hanafi Puspa Dewi N. Lotulung Muhammad Eka Prastya Chandrabhan Verma Akram Alfantazi Azwar Manaf Postgraduate Program of Materials Science Study Department of Physics Faculty of Mathematics and Natural Sciences Universitas Indonesia Depok 16424 Indonesia Research Center for Metallurgy National Research and Innovation Agency (BRIN) Tangerang Selatan Banten 15314 Indonesia Research Center for Pharmaceutical Ingredients and Traditional Medicine National Research and Innovation Agency (BRIN) Tangerang Selatan Banten 15314 Indonesia Research Center for Chemistry National Research and Innovation Agency (BRIN) Tangerang Selatan Banten 15314 Indonesia Department of Chemical Engineering Khalifa University of Science and Technology P. O. Box 127788 Abu Dhabi United Arab Emirates

This work extracted the Tinospora cordifolia stem for antibacterial and antioxidant materials. The stems of T. cordifolia were extracted by using a simple maceration method. The effect of three independent variables (solvent ratios, temperature, and extraction time) was investigated to obtain optimal conditions. Ten grams of T. cordifolia were extracted using a mixture of methanol–water ratios 00:100, 15:85, 30:70, and 45:55 (% v/v) at 50–95 °C for 0.5 to 3 h. The total phenolic and flavonoid content in the T. cordifolia extracts was analyzed by Folin-Ciocalteu and Colorimetric-AlCl 3 methods. The antibacterial activities against Pseudomonas aeruginosa were assessed by serial dilution methods, and antioxidant properties were performed by DPPH methods. The optimum condition was achieved at methanol–water ratios of 00:100 % (v/v) at 95 °C for 2 h. The yield extraction for this condition is around 13.97%. The total phenolic and flavonoid contents for these conditions are about 6.85% and 7.07%, respectively. The minimum inhibitory concentration value against P. aeruginosa is 1024 µg/mL, and the minimum bacterial concentration is above 2048 µg/mL. Meanwhile, the antioxidant obtained is 217.55 µg/mL at a ratio of 00:100 methanol–water. The extraction process parameters significantly influenced the phytochemical (TPC and TFC), antibacterial activity, and antioxidant properties of T. cordifolia stem extracts. This work clearly shows the antibacterial potential of T. cordifolia stem extracts, suggesting that more investigation is required to isolate the bioactive compounds in this extract.

关键词： Antibacterial Antioxidant Maceration Parameter effect P. aeruginosa T. cordifolia

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Antioxidant Effects of Vitamin C on Biomedical UHMWPE Compounds

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Macromolecular Symposia 2019年第1期383卷

作者： Souza, Vanessa C. Fim, Fabiana C. Lima, Maria Edvania A. Silva, Lucineide B. Postgraduate Program in Materials Science and Engineering – CT/ UFPB Cidade Universitária s/n João Pessoa/PBCEP: 58051-900 Brazil Cidade Universitária s/n João Pessoa/PBCEP: 58051-900 Brazil

The aim of the present study is to evaluate the antioxidant activity of ascorbic acid (Vitamin C) at concentrations of 0.5, 1.0, and 2.0% wt on Biomedical Ultra High Molecular Weight Polyethylene (B-UHMWPE), using a stable free radical 2,2-diphenyl-1-picryl-hydrazyl (DPPH). The compounds are prepared by compression molding at 160 °C for 6 min, and pressure of 10 MPa. Infrared spectroscopy indicated a weak interaction between the compound constituents, at 3600, 1800, and 1500 cm−1 bands attributed to Vitamin C. Atomic force microscopy (AFM) revealed that the addition of 2.0% wt. of Vitamin C promoted B-UHMWPE crystalline particle size decreases and molecular disorder. In the presence of the vitamin, Raman spectroscopy suggested a decrease in the degree of polymer crystallinity which may be attributable to modifications in morphological aspects of the polymer. Vitamin C acted as an antioxidant agent, an important result;an increasing amount of radical is scavenged with the addition of the vitamin to the compounds. Thus, Vitamin C presents potential as an antioxidant for B-UHMWPE compounds. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

关键词： Infrared spectroscopy

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Synergetic Phenomenon between Structural Distortion and Cobalt Valence State and its Effect on the Oxygen Evolution Reaction in Cobalt Ferrites

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Ceramics International 2025年

作者： Fabiano R. Praxedes Thayse R. Silva Maria C.M. Ferreira Marcos A.L. Nobre Daniel A. Macedo Silvania Lanfredi Department of Chemistry and Biochemistry São Paulo State University (Unesp) School of Technology and Sciences R. Roberto Simonsen – 305 CEP: 19060-900 Presidente Prudente - SP Brazil São Paulo State University (Unesp) Institute of Biosciences Humanities and Exact Sciences São José do Rio Preto SP 15054-000 Brazil Materials Science and Engineering Postgraduate Program Federal University of Paraíba (UFPB) 58051-900 João Pessoa - PB Brazil Department of Physics São Paulo State University (Unesp) School of Technology and Sciences R. Roberto Simonsen – 305 CEP: 19060-900 Presidente Prudente - SP Brazil

Nanopowders of cobalt ferrite with the stoichiometry Co x Fe 3-x O 4 (0.4 ≤ x ≤ 1.2) were synthesized at 80 °C using a co-precipitation method. The resulting crystalline, single-phase powders were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Morphological analysis of the cobalt ferrite nanoparticles revealed the formation of spherical particle agglomerates at the nanoscale. Chemical bond analysis by infrared spectroscopy, based on the deconvolution of absorption bands, together with structural characterization by XRD and Rietveld refinement, confirmed the formation of a spinel-type phase with cubic symmetry and space group Fd-3m. The improved electrocatalytic performance was observed for the sample with the highest Co content (Co 1.2 Fe 1.8 O 4 , requiring 320 mV to achieve 10 mA cm -2 ). The structure-activity relationships indicate the OER mechanism in our cobalt ferrites is governed by three interconnected factors: octahedral Co 3+ dominance, bond-angle flexibility, and increased Co content, synergistically enhancing catalytic efficiency.

关键词： Electrocatalysis Nano ferrites Oxygen evolution reaction Spinel structure

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Devulcanization of natural rubber in composites with distinct crosslink densities by twin-screw extruder

Devulcanization of natural rubber in composites with distinc...

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作者： Barbosa, Rafael Nunes, Anderson Thadeu Ambrósio, José Donato Materials Science and Engineering Postgraduate Program - PPGCEM Federal University of São Carlos - UFSCar São Carlos SP Brazil Center of Characterization and Materials Development - CCDM Federal University of São Carlos - UFSCar São Carlos SP Brazil

In this study, the effects of the devulcanization process realized by an intermeshing co-rotating twin-screw extruder (ICTSE) on three vulcanized Natural Rubber (NR) composites with different crosslink densities (CD) have been investigated. The extrusion parameters were fixed, as well as the initial material granulometry and auxiliary thermoplastic added to the process. After composites vulcanization, they were characterized accordingly their soluble fraction (SF), crosslink density (CD), mechanical properties and thermogravimetry (TGA). The extrusion was performed on the vulcanized elastomers pursuing selectively crosslink rupture and the same characterization previously cited was conducted on the devulcanized material, except the mechanical properties analysis. The extrusion demonstrate effective devulcanization, evidenced in the increasing of soluble fractions, reduction in crosslink density and thermal stability gain. These results are directly affected by preliminary differences on materials structure and presence of ethylene vinyl-acetate (EVA) on extrusion. © 2017 Universidade Federal de Sao Carlos. All rights reserved.

关键词： Rubber

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Characterization of ZnAl2O4 spinel obtained by hydrothermal and microwave assisted combustion method: A comparative study

Characterization of ZnAl2O4 spinel obtained by hydrothermal ...

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作者： De Macedo, Heloísa Pimenta De Araújo Medeiros, Rodolfo Luíz Bezerra De Medeiros, Amanda Lucena De Oliveira, Ângelo Anderson Silva De Figueredo, Gilvan Pereira De Freitas Melo, Marcus Antônio De Araújo Melo, Dulce Maria Postgraduate Program in Science and Engineering of Materials Federal University of Rio Grande do Norte - UFRN Natal RNCEP 59078-970 Brazil Postgraduate Program in Science and Engineering of Petroleum Federal University of Rio Grande do Norte - UFRN Natal RNCEP 59078-970 Brazil Postgraduate Program in Chemistry Chemistry Institute Federal University of Rio Grande do Norte - UFRN Natal RNCEP 59078-970 Brazil Chemistry Department Federal Institute of Education Science and Technology of Maranhão - IFMA São LuísMACEP 65076-091 Brazil Department of Chemical Engineering Federal University of Rio Grande do Norte - UFRN Natal RNCEP 59078-970 Brazil

In this work, zinc aluminate spinel was prepared by two methods of directly synthesis (without calcination): microwave assisted combustion and hydrothermal method. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2-adsorption/ desorption isotherms. The XRD patterns confirmed the formation of cubic ZnAl2O4 spinel structure with no secondary phases for both synthesis routes, whereas the hydrothermal method yielded powders with crystallite size 3 times smaller (6.9 nm), as compared to the powders produced by microwave assisted combustion method (25.6 nm). The micrographs revealed agglomerated powders with plate-like morphologies for both routes. Nitrogen adsorption/desorption isotherms (BET) revealed higher surface area (183 m2.g-1) and greater pore volume (0.173 cm3.g-1) for ZnAl2O4 powders prepared by the hydrothermal method. © 2017 Universidade Federal de Sao Carlos. All rights reserved.

关键词： Zinc compounds

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High-Temperature Oxidation Behavior of Fe-18Al Alloy Added with 2 %ZrO2 Nanoparticles

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IOP Conference Series: materials science and engineering 2019年第1期515卷

作者： P Pawawoi D H Prajitno A A Dewi A Manaf Postgraduate Program of Materials Science Study Department of Physics Faculty of Mathematics and Natural Sciences Universitas Indonesia Depok 16514 PTNBR- BATAN Jln. Tamansari 71 Bandung 40317 Bandung Metallurgical Engineering of Jenderal Achmad Yani University Jln. Gatot Subroto PO. Box 807 Bandung 40285

The oxidation behaviour of ZrO2 nanoparticles added to Fe-18Al alloy has been studied. Isothermal oxidation behaviour with various temperatures and times was investigated and the results of microstructure showed the presence of Fe3Al intermetallic phases in grey color, Al2O3 oxide in white color, and the porosity indicated by dark color. The results of XRD and SEM-EDS analysis also confirmed the presence of the ZrO2 nanoparticles in addition to Fe3Al intermetallic phases and Al2O3 oxide phases. The addition of ZrO2 nanoparticles tended to decrease oxidation rate by promoting Al2O3 layers.

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