1,720,958 research outputs found
Self-Cleaning Mineral Paint for Application in Architectural Heritage
Get PDFA mineral silicate paint has been developed for architectural heritage. To enhance durability, any type of organic additive has been avoided. Potassium silicate was the binder agent intended to give strong adherence and durability to stone and concretes. Incorporation of mainly anatase titanium dioxide was intended to act both as a white, bright pigment and as a photocatalyst. Reflectivity analyses on the paint in the visible-to-near infrared wavelength region show high solar heat reflection. The self-cleaning activity of the mineral paint was evaluated by the degradation of organic dyes under solar light irradiation. Anatase titania was effective in decomposing organic and airborne pollutants with the solar radiation. The optical properties and self-cleaning activity were compared with the organic binder-based paints and commercial paints. Developed paints possess high stability: since they contain only inorganic components that do not fade with exposure to solar radiation, photocatalytic self-cleaning capability further enhances such stability
Easy-to-fill asymmetric polymeric micro-reservoirs
No full textIn this work, we demonstrate the feasibility of micrometric asymmetric reservoirs made of thermoplastic polymers by using the gas foaming method, which has been recently introduced, and consists in forming bubbles in micro- or nano-metric bulk particles as it is done with carbonated drinks. As this simplicity anticipates, this represents a breakthrough in the area of micro and nano-particles as it responds to the needs of: i) breaking the symmetry of commonly available systems, ii) filling the particles with a multitude of host molecules and solutions, iii) having different shapes, iv) having a wide range of particle dimensions, v) having particles made of a wide range of materials. Here we report the achievement of micrometric spherical particles and of micrometric ellipsoidal particles with eccentric holes, filled with crystal violet or with quantum dots as model host molecules. Raman spectroscopy and optical and electron imaging are utilized to verify the effectiveness of the method. This study should open up the use of micro- and nano-metric reservoirs in a multitude of research areas, from the biomedicine and pharmacology, to electronics, energy and optics
Mechanical and tribological properties of injection molded zirconia-alumina for orthopedic implants
Get PDFCeramics have gained great attention for hip and knee arthroplasty surgical procedures due to their ability to guarantee long-life performance in patients and are considered an alternative to existing metal systems.In the present study, zirconia toughened alumina (ZTA) for orthopaedic implants has been developed by Ceramic Injection Molding (CIM) process. Microstructural, mechanical and tribological studies have been carried out to establish whether the material is suitable for the purpose. The new CIM ZTA material obtained density up to 99.4%, toughness 6.1 MPa m1/2, hardness 20 GPa, Young's modulus 320 GPa, and low coefficient of friction ranging between 0.08 and 0.13 under lubricated conditions, and between 0.11 and 0.34 in dry condition. To simulate the performance of the ZTA in vivo, i.e., the influence of material degradation on the ageing properties, accelerated hydrothermal aging was performed in vitro and good mechanical and tribological properties were confirmed for the developed ZTA
Mechanical properties characterisation of AlSi10Mg parts produced by laser powder bed fusion additive manufacturing
No full textAdditive manufacturing refers to a wide class of manufac- turing processes based on the progressive building of func- tional parts through the addition of material layer upon layer. These technologies were first confined to prototyp- ing, but the subsequent development of additive manufac- turing processes for further materials, such as metals, has encouraged their worldwide industrial spread, from the bio- medical field to the automotive and the aerospace indus- tries. Additively manufactured parts are required to meet high and stable performance, at least comparable to that of conventional wrought materials, so as to comply with strict and well-defined international standards. This paper pre- sents an investigation into the mechanical properties of Al- Si10Mg parts produced by laser powder bed fusion techni- que, using different spatial orientations within the build volume. The effects of the part position and orientation on the static (tensile) properties of the produced parts were as- sessed by means of the two-way analysis of variance techni- que. The build angle was found to be the most effective pa- rameter, while the variability ascribable to the effect of part position resulted mainly as physiological. The fatigue resis- tance showed a globally decreasing trend with increasing build angle
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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