1,720,975 research outputs found
Electrophoretic deposition: An effective technique to obtain functionalized nanocoatings
No full textNowadays, perovskite-structured (e.g., ferrite, cobaltite, and manganite) and other oxide (e.g., titania, zirconia, and yttria) coatings are of great interest in industrial applications such microelectronics, metal corrosion protection, photocatalytic degradation of organic pollutants, and electrochemical energy conversion devices. Different techniques, like pulsed laser deposition, magnetron sputtering, combustion chemical vapor deposition, chemical vapor deposition, are currently used to prepare homogeneous, thin and dense nanofilms. This work aims at exploring the electrophoretic deposition as an effective technique able to obtain functionalized nanocoatings due to its advantages with respect to the aforementioned deposition techniques. Electrophoretic deposition main advantages include simplicity of the method, high versatility, the possibility to control the structure, film thickness size scalability (from few nm up to tens of microns) and the possibility to form multilayer films with low-cost equipment at high deposition rates. In addition, to deposition time, suspension concentration, electrode distance, and applied voltage are crucial to tailor the layer thickness and uniformity
Glass and glass-ceramic matrix composites for advanced applications: Part II: Applications
No full textGlass and glass-ceramic matrix composites (GMCs and GCMCs) have found numerous technical applications in different industrial sectors due to their unique combination of properties. The most popular applications of such composites are presented in this article. In the aerospace sector, for example, glass and glass-ceramic composites are proposed for the manufacturing of complex shape and precision parts with superior mechanical properties and high temperature capability, thanks to the presence of ceramic reinforcements. In the case of solid oxide fuel cells (SOFC), standard compositions of glass and glass-ceramic seals have been reinforced by the inclusion of second phases to improve specific properties of CMCs of interest in SOFC technology. In the field of biomaterials, glass and glass-ceramic matrix composite materials are candidate materials for use in the areas of bone substitution and repair, dental restoration, scaffolds for tissue engineering and drug delivery devices. The use of glass and glass-ceramic matrix composites as substrates for electronic packages is also reported. A detailed description of different usages of GMCs and GCMCs as structural material in a broad range of advanced applications is presented. In most applications, the second phase is considered a mechanical reinforcement with the main goal being the increase of mechanical strength and fracture toughness, without affecting other specific properties relevant for the application considered, such as biocompatibility, electrical properties and translucency of the matrix
Glass and glass-ceramic matrix composites for advanced applications: Part I: Properties and manufacturing technologies
No full textGlass and glass-ceramic matrix composites are a special group of ceramic materials, which are the object of continuous academic and industrial research, due to the wide range of properties and superior performance that these materials can achieve and that allow their use in a wide range of applications. They consist of a glass or semi-crystalline matrix (glass-ceramic, developed from controlled crystallization of a glass) incorporating a “reinforcing” phase. Depending on the morphology of the second phase, composites can be classified as dispersion or particle reinforced, laminated reinforced and fiber-reinforced. Varying the microstructure and chemical composition of the glass/glass-ceramic matrix and the nature and distribution of reinforcements, the properties of the composites can be tuned to meet different requirements. The materials developed may be transparent or opaque and they can exhibit almost zero thermal expansion and high fracture toughness. In addition, they are usually resistant to thermal shock and have a high impact resistance and temperature/oxidation capability. Unlike polycrystalline ceramic matrices, glasses show viscous flow, which enables them to be shaped and densified at lower temperatures than their ceramic matrix counterparts which leads to cost-effective manufacturing. This article will review the field of glass and glass-ceramic matrix composites in terms of systems investigated, fabrication technologies and properties
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Bioactive glass applications: A literature review of human clinical trials
Full text linkThe use of bioactive glasses in dentistry, reconstructive surgery, and in the treatment of infections can be considered broadly beneficial based on the emerging literature about the potential bioactivity and biocompatibility of these materials, particularly with reference to Bioglass® 45S5, BonAlive® and 19-93B3 bioactive glasses. Several investigations have been performed (i) to obtain bioactive glasses in different forms, such as bulk materials, powders, composites, and porous scaffolds and (ii) to investigate their possible applications in the biomedical field. Although in vivo studies in animals provide us with an initial insight into the biological performance of these systems and represent an unavoidable phase to be performed before clinical trials, only clinical studies can demonstrate the behavior of these materials in the complex physiological human environment. This paper aims to carefully review the main published investigations dealing with clinical trials in order to better understand the performance of bioactive glasses, evaluate challenges, and provide an es-sential source of information for the tailoring of their design in future applications. Finally, the paper highlights the need for further research and for specific studies intended to assess the effect of some specific dissolution products from bioactive glasses, focusing on their osteogenic and angio-genic potential
Insight into t->m transition of MW treated 3Y-PSZ ceramics by grazing incidence X-ray diffraction
No full textThe influence of a microwave hybrid heat treatment (MHH) on the surface and in-depth mineralogical transformation of pre-sintered 3Y-PSZ was investigated. 3Y-PSZ samples were prepared by slip casting and sintered by conventional firing (1270 °C). Then, different MHH treatments from 5 to 15 min. at 1200 °C were applied to obtain a fully stabilized 3Y-TZP. The monoclinic fraction depth profiles in the first micrometres (up to 5) of thickness were investigated by means of the grazing incident X-ray diffraction technique (GIXRD). A good sintering degree with practically nil closed porosity and grain growth was achieved after MHH of 15 min. MHH increases the tetragonal phase content both in the surface and in-depth, reducing completely the monoclinic phase shell typically found after conventional sintering. A new parabolic model is proposed for the convoluted monoclinic fraction depth profile, which through the value of its horizontal asymptote allows the determination of the monoclinic shell thickness
Preliminary study on the design of superhydrophobic surface by 3D inkjet printing of a sol-gel solution
No full textIn this study a novel and straightforward 3D printing method based on inkjet printing process for the design of superhydrophobic surfaces was investigated. In particular, a novel sol-gel solution was designed and used with a modified 3D printing approach based on micro-solenoid inkjet printing. The study focuses on the impact of roughness and chemical composition - both crucial factors in achieving superhydrophobic properties - by measuring the contact. In addition, tilt angle of water droplets on different coating were determined. It is believed that the simple new inkjet printing method presented here can expand the application of the superhydrophobic high and low adhesive surface on different substrates for application in many industrial fields. [Figure not available: see fulltext.
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