1,721,068 research outputs found
Evaluations of the reuse of municipal solid waste incinerator bottom ashes as aggregated materials in civil applications
No full textDehydration mechanism of AlPO4-5: A high-resolution synchrotron X-ray powder diffraction study
Full text linkWe present the results of a study on the thermal stability and dehydration dynamics of the porous alumino-
phosphate AlPO4-5, from room temperature to 850 °C, carried out by in situ synchrotron X-ray powder dif-
fraction experiments. No phase transitions were observed in the investigated T range. Due to the very low
interactions among framework and water molecules, dehydration is already complete at 152 °C. It occurs in two
main T ranges, one between 60 and 80 °C and the second one between 90 and 120 °C. During these two stages,
the cell volume tends to increase to facilitate the water release. Overall, across the full explored T range, the cell
volume increase is only 0.84%, indicating that AlPO4-5 is one of the most rigid zeolite frameworks studied to
date. Specifically, after complete dehydration at 200 °C, AlPO4-5 undergoes a negative thermal expansion as a
consequence of the decrease in both a and c cell parameters. The expansion coefficients for V, a and c cell
parameters, in the 152–850 °C range, are αV = −7.12 (10−6/K), αa = −2.5 (10−6/K), αc = −2.2 (10−6/K),
respectively
Effects of particle size on properties and thermal inertization of bottom ashes (MSW of Turin’s incinerator)
Full text linkThe aim of this study is twofold: (i) characterization of the bottom ashes from the Incinerator plant of the city of Turin (northern Italy), in terms of their chemical/phase compositions and capacity to release heavy metals in leachates, as a function of particle size; (ii) investigation of thermal treatments’ efficacy to promote inertization of the same bottom ashes, exploring time-temperature ranges with t ≤ 6 h and T ≤ 1000 °C. Special attention is paid to macro-sampling techniques in order to have samples that are representative of the average bottom ashes production. Micro-XRF, ICP-OES, SEM-EDS, Ion Chromatography and X-ray powder diffraction were used to investigate bottom ashes and leachates. Bottom ashes are mainly constituted by an amorphous phase, ∼66–97 wt%, regardless of particle size; the remaining phases are quartz, calcite, Fe-oxides, melilite and other minor crystalline materials. The amorphous phase exhibits a relevant dependence on particle size, and undergoes dissolution in water up to 20 wt%, thus being the most important component in affecting chemical species release. The smaller the bottom ashes’ particle size, the more the heavy metals (major species: Zn, Cu, Ti, Pb) and calcium contents increase, whereas silicon’s decreases. Electrolytic current observations in combination with phase/chemical composition and metals release as a function of particle size, suggest that bottom ashes partition into two classes, i.e. ≥1 and <1 mm, for inertization purposes. Thermal treatments exhibit partial efficacy to curb heavy metals mobility: whilst they reduce Cu release, they lead to a inverse effect in the case of Cr
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
Zeolite/dye hybrid composites: Organization of photoactive azobenzene molecules inside AlPO4-5
Full text linkOrganic/inorganic hybrid materials - like zeolites +dyes - are currently used in strategic areas, from sustainable
energy technologies to biomedical sciences. In these systems, photoactive molecules are organized in one-dimensional
nanostructures inside the zeolite channels. In this paper we present the results of a study aimed to the
synthesis and the structural and spectroscopic characterization of azobenzene/AlPO4-5 hybrid composites,
performed by a multi-technique approach based on material synthesis, thermal gravimetric analysis, synchrotron
X-ray powder diffraction, UV-VIS and IR spectroscopies. The results indicate that azobenzene molecules are
hosted in the 12-membered ring channel of AFI framework and the maximum loading is 0.9 molecules per unit
cell. The combination of spectroscopic and diffractometric methods point out that, being AlPO4-5 starting material
affected by Brönsted acidity, a consistent portion of the azobenzene molecules is protonated and interact
with the framework oxygen atoms
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
Computational approach to the study of epitaxy: Natural occurrence in diamond/forsterite and aragonite/zabuyelite
Full text linkIn
this contribution the theoretical and computational aspects
related to the determinations of the (i) interface structure, (ii)
adhesion energy, and (iii) interfacial energy of a system composed
by two crystalline phases in epitaxial relationship are discussed.
Specifically, we describe the possible 2D lattice coincidences between
two phases in epitaxial relationship, as well as all of the possible
initial interface configurations which generate when different surface
terminations of the phases put in contact are taken into account.
Then, in order to elucidate these theoretical aspects, we have studied
the following epitaxies in natural systems: {110}-diamond (C)/{101}-forsterite
(Mg<sub>2</sub>SiO<sub>4</sub>) and {001}-aragonite (CaCO<sub>3</sub>)/{1̅01}-zabuyelite (Li<sub>2</sub>CO<sub>3</sub>); the optimized
interface structures and their adhesion energies were determined at
the ab initio level. For the diamond/forsterite system, a very low
value of the adhesion energy was estimated, β<sub>(110)/(101)</sub><sup>D/Fo</sup> = 0.367 J/m<sup>2</sup>, suggesting a low probability to have epitaxy between {110}-diamond
and {101}-forsterite. A higher adhesion energy was instead found for
the aragonite/zabuyelite system, β<sub>(1̅01)/(001)</sub><sup>Za/Ar</sup> = 0.595 J/m<sup>2</sup>, which reveals
a strong affinity between the {1̅01}-zabuyelite and {001}-aragonite
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