This paper provides an overview of the macroscopic properties of porcelain tableware fired in a microwave furnace with six magnetrons (each with a nominal power of 900 W) operating at the frequency of 2.45 GHz. The dependence of firing temperature on physical properties such as shrinkage, water absorption, apparent porosity, bulk density, and impact resistance was analyzed. Emphasis is on the differences in the macroscopic properties of microwave and conventionally (gas and electric) fired porcelain. Batches were fired from room temperature up to above the optimum firing temperature (1380°C). Results show similar macroscopic properties for both firing methods, microwave heating required lower firing temperatures (between 1300°C and 1350°C), and shorter processing times (about 70 minutes). The main differences between microwave and electric firing methods occur in a temperature band of 300°C above the porcelain eutectic temperature (close to 1000°C).

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We have investigated the electrical properties of carbon black (CB) loaded in ethylene butylacrylate copolymer composite (EBA) in the frequency range between 10² and 10⁴ Hz and temperature range between 153 and 353 K. The frequency dependence of electrical data that have been analyzed in two frameworks: the electrical modulus formalism with the Kohlrausch-Williams-Watts stretched exponential function (KWW) and the electrical conductivity by using the Jonscher’s power law in the frequency domain. The stretching exponent β_KWW and n are found to be temperature independent for all CB fractions and to be decreased when the CB volume concentrations loaded in copolymer matrix increases. It is found that the activation energy obtained by the modulus method is in good agreement with that obtained by the DC conductivity in the power law which is independent on the CB contents that exist in the copolymer matrix, suggesting that these particles do not interact significantly with the chain segments of the macromolecules in the EBA copolymer

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The optical and the dielectric properties of an original nanocomposite based on the incorporation of carbon dots (C‐dots) in poly(methyl methacrylate) (PMMA) at several filler loading were studied. The optical characterization demonstrated the preservation of the excitation dependent intense emission of the C‐dots in the polymer, ascribed to the presence of organic fluorophores formed during the nanoparticle synthesis. The composite PMMA/C‐dots dielectric properties were investigated in the frequency range from 40 Hz to 1 MHz and over the temperature range from 200 to 400 K. The dielectric response was obtained using the complex permittivity or the modulus formalisms, depending on the concentration of filler in the polymer matrix. A relaxation phenomenon was induced by the incorporation of the C‐dots in the PMMA matrix. In addition, both the real and imaginary parts of the dielectric permittivity and electric modulus changed with the volume fraction of the C‐dots, suggesting that the presence of the fillers greatly affect the dielectric properties of the polymer matrix because of polarization phenomenon induced by the nanoparticles. POLYM. COMPOS., 40:E1312–E1319, 2019. © 2018 Society of Plastics Engineers

In this paper we describe SUPeRB, a digital librarian helper, which has two specific goals: update and maintain specific publication repositories; and assist in the publishing of publication records, for institutions and individual actors. It does this by gathering bibliographic data from web pages and documents in order to build a local repository of bibliographic data on a specific subject. Also, by collecting information from these resources, SUPeRB assists in building a bibliographic database with specific domain intervenients such as authors, conferences and scientific journals. ResumoEste artigo descreve o SUPeRB, um sistema para procurar e tratar referências bibliográficas na Web, que possui dois objectivos: actualizar e manter repositórios de publicações numaárea específica; e assistir na publicação de dados bibliográficos de instituições ou de investigadores individuais. Para tal, o SUPeRB recolhe informação de páginas e documentos electrónicos, construindo um repositório local de referências bibliográficas daárea. Ao construir estes recursos, o SUPeRB cria ainda uma base de conhecimento num determinado domínio, contendo autores, conferências e revistas científicas. Categories and Subject Descriptors General TermsExtracção de informação, Gestão de informação, Referências Bibliográficas INTRODUÇÃODesde 1999 que a Linguateca disponibiliza um portal dedicado ao processamento computacional do português com o objectivo de fornecer uma boa panorâmica a todos os interessados nestaárea. O nosso objectivo foi desde o início garantir a existência de um local que permita aos investigadores e programadores seguirem o trabalho feito nestaárea, de forma a evitar repetição de esforços e potenciando, ao invés, colaborações entre diferentes instituições realizando esforços complementares. Um dos recursos que mantemosé um catálogo de publicações relacionadas com o processamento computacional do português. Entre 1999 e 2003, recolhemos manualmente cerca de 750 entradas, incluindo, quando disponíveis, as suas versões electrónicas. Embora a nossa equipa acompanhe as listas de discussão e de artigos aceites em conferências relevantes para aárea, chegá-mosà conclusão que não era fácil manter este recurso actualizado.É particularmente difícil encontrar a informação completa sobre artigos e outras publicações científicas, dado que muitos investigadores não actualizam as suas páginas de publicações frequentemente. Para além disto,é comum encontrarmos outras dificuldades para obter e processar esta informação, tais como:• Referências incompletas, onde se omitem por exemplo os nomes completos das conferências, os editores dos volumes, as edições das conferências ou a sua localizacão;• Vários estilos bibliográficos usam as iniciais dos autores, o que complica a tarefa de os identificar automaticamente;• As versões electrónicas não são exactamente iguaisàs versões publicadas (pelo menos no que diz respeitoà formatação).E também de referir que quase nenhum dos autores com trabalhos no nosso catálogo usa meta-informação ou qu...

Nowadays, the development of sustainable high-performance functional nanomaterials is in the spotlight. In this work, we report the preparation of a new generation of flexible and high electroconductive nanopapers based on nanofibrillated cellulose (NFC) and copper nanowires (CuNWs). Homogeneous red brick color nanopapers (thickness 30.2−36.4 μm) were obtained by mixing different amounts of NFC aqueous suspensions and CuNWs (1, 5, 10, 20, and 50 wt %), followed by vacuum filtration and drying. scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis confirmed the incorporation of the different amounts of CuNWs, and their uniform and random distribution. All of the nanomaterials displayed good mechanical properties, viz., Young's modulus = 2.62−4.72 GPa, tensile strength = 30.2−70.6 MPa, and elongation at break = 2.3−4.1% for the nanopapers with 50 and 1 wt % of CuNWs mass fraction, respectively. The electrical conductivity of these materials strongly depends on the CuNW content, attaining a value of 5.43 × 10 4 S•m −1 for the nanopaper with a higher mass fraction. This is one of the highest values reported so far for nanocellulose-based conductive materials. Therefore, these nanopapers can be seen as an excellent inexpensive and green alternative to the current electroconductive materials for applications in electronic devices, energy storage, or sensors.

Binary and ternary composites were synthesized using a polyester matrix reinforced by two types of carbon inclusions, namely, carbon nanotubes (CNT) and graphite (Gt) (CNT/Gt/Polyester). Thermal analyses were performed, using thermogravimetry and differential scanning calorimetry, which allowed us to observe significant changes in glass transition temperatures and degradation temperatures of the composites. Dielectric measurements were performed in a frequency range from 100 Hz to 1 MHz and temperature from –33 to 107°C. The dielectric permittivity values of the CNT/Gt/Polyester ternary composites, compared to the Gt/Polyester binary composites, indicate that the addition of CNT particles to the Gt/Polyester binary system significantly improved the dielectric permittivity, due to the enhanced interfacial polarization of the host matrix, while the frequency dependence of the electrical modulus spectra revealed a Maxwell–Wagner–Sillars dielectric relaxation process that was found to follow the Cole–Davidson approach.