1,720,961 research outputs found
Sistema di afferraggio autoallineante e antibuckling per prove statiche e di fatica su provini snelli, di geometria regolare e di qualsiasi materiale
No full textIl brevetto propone un sistema di afferraggio a morsetti autoallineati per prove statiche e di fatica su provini, normalizati e non, di geometria regolare e di qualsiasi materiale.
Esso consiste in due capsule recanti, ciascuna, una cavità coassiale che ospita due morsetti a cuneo per afferrare un’estremità del provino. Morsetti e provino sono attraversati, nella zona centrale dalla superficie di contatto reciproco, da una spina che li rende solidali, gli uni all’altro. L’estremità delle capsule non impegnata dal provino ha una geometria idonea ad un accoppiamento prismatico con uno stelo di prolunga, all’interno del quale scorre un’asta, che, spingendo sui cunei, blocca il provino nella capsula
APPLICATION OF SOFTWARE FOR THE SURFACE SHAPE OF THE CHESTNUTS HARVEST NETS
No full textIn this research conveyance nets for the chestnuts harvest have been considered and the optimization of the surface shape of the chestnuts harvest nets has been performed. Indeed, a steep zone with chestnut trees has been considered, with maximum length of 90 m and maximum width of 60 m and the geometric model of the considered zone has been obtained, by mean GIS system and “Archicad 14” program code, obtaining also the soil local slope distribution. The chestnuts fallen have been simulated by mean a “rain device” available in “Sitetopo” program code. This program has allowed to evaluate the rain draining in function of the considered surface slope. Further, the zone with lower quote, for the considered surface, is the zone in that the chestnuts have to be convoyed, “basin zone”. Indeed, by mean “Sitetopo” program code, it has been possible to evaluate the rain draining contour-plot, and the conveyance effect, that is, where the rain flow is convoyed. This has been obtained by changing of the net surface slope on that, the rain (simulating the chestnuts) fallen. Indeed the nets have been located following the determined optimal surface. In such way all the fallen chestnuts have been convoyed and picked in a determined zone, “basin zone”, and subsequently they have been loaded on the truck for the following workmanships. The evaluated losses have been of around 6-8 % due to chestnuts entangle or little branches obstacle
Supercritical Fluid Extraction of alfa- and beta-acids from Hops Compared to Cyclically Pressurized Solid-liquid Extraction
No full textIn this paper, two solid–liquid extraction techniques, supercritical fluid extraction (SFE) with and without
modifiers and cyclically pressurized solid–liquid extraction with a Naviglio Extractor, were compared on
the basis of extraction of acidic compounds contained in hops flowers. The hops extracts were analyzed
by electro-kinetic capillary chromatography (MECK). The results showed that the technique using supercritical
carbon dioxide was more effective for the isolation of acids; the use of ethanol as a co-solvent,
as reported in the literature, produced a heterogeneous extract, while cyclically pressurized solid–liquid
extraction showed a greater extraction capacity for acids. Consequently, both techniques are valid for
the extraction of and acids from hops. By suitably varying the parameters of the two extractive procedures,
it will be possible to obtain extracts for use in the production of beer and dietary supplements
and drugs. Furthermore, based on the SFE CO2 extraction process, a mathematical model was applied
to the examined process, and a numerical simulation was performed, leading to a model that provides
direction for the optimization of further experiments
DESIGN OPTIMIZATION OF THE PLOUGH WORKING SURFACE BY COMPUTERIZED MATHEMATICAL MODEL
No full textIn this paper, a procedure for the optimization of the working surface of a plough for a soil type considered and to analyze the efficiency, is performed. It fits in the set of numerical – experimental techniques used for the improvement of the energy performance related to ploughing of agricultural soil. In the first part of this paper, it describes how to generate a family of working surfaces for assigned geometrical and process parameters; latter, by mean the use of a physical-mathematical model which describes the soil - plough interaction, it is examined the draught resistance changing in function of the geometric and process parameters for a soil considered, aimed to optimize the shape. A commercially available plough, subsequently, was examined and, applying such methods, its parametric representation and the optimized surface were obtained for the examined soil
Supercritical fluid extraction of pyrethrins from pyrethrum flowers (Chrysanthemum cinerariifolium) compared to traditional maceration and cyclic pressurization extraction
No full textIn this work, a comparison between three extraction processes, including traditional maceration in n-hexane and ethyl alcohol, supercritical fluid extraction (SFE) and cyclically pressurized extraction known as rapid solid-liquid dynamic extraction (RSLDE), has been carried out for the extraction of pyrethrins, predominantly nonpolar natural compounds with insecticidal properties found in pyrethrum, an extract of certain species of chrysanthemums. Pyrethrins are often used in household insecticides and for the control of parasites on pets or livestock. Maceration is the cheapest method, but the values of the percent of extracted material compared to the weight of the dried flowers are lower. The extraction with supercritical CO2 is less efficient than the Naviglio extractor, but it has the advantage of not requiring the use of solvents. Consequently, all three techniques are valid for the extraction of compounds from pyrethrum flowers. The results obtained show that by suitably varying the parameters of the three extraction procedures, it is possible to obtain pyrethrin extracts for use in the production of low toxicity insecticides for warm-blooded animals and low pollution. In particular, extraction with supercritical CO2 presents an additional advantage; although oleoresin is a natural product, its extraction involves the use of solvents, while SFE is a highly efficient extraction process due to the use of CO2 in the supercritical phase without the use of solvents. On the other hand, the Naviglio extractor is an inexpensive technique and requires a minimum energy loss when compared to the extraction with supercritical fluids. Thus, the latter is more convenient on an industrial level but is not universally applicable. Nevertheless, the supercritical extraction can be used as a medium detergent of the oleoresin produced to avoid residues of the solvents left during the extraction process. Therefore, for demonstration purposes, for the SFE CO2 extraction process, numerical simulations have been performed, allowing for helpful results to optimize the process for further tests
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
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