1,721,036 research outputs found
Effetto del diverso regime idrico sulla fisiologia della pianta e sulla composizione degli acini del vitigno aleatico
No full textA non-invasive optical method for quality control of maturing wine grapes
No full textAccumulation of anthocyanins (Anth) in whole winegrape (Vitis vinifera L.) bunches still attached to vine plants was followed non-destructively using a fluorescence-based sensor. The method is based on the screening of fruit chlorophyll fluorescence and allows the Anth contents of intact berry skin to be measured. With increasing Anth content, less excitation light is transmitted to the deeper chlorophyll layers, and thus the chlorophyll fluorescence signal decreases proportionally. Tests were carried out in 2009-2010 in vineyards of Central Italy. Measurements were performed weekly from véraison to harvest on Sangiovese, Cabernet Sauvignon, Merlot, Shiraz and Petit Verdot cultivars. The ANTHRG index showed a different time evolution and Anth accumulation for the cultivars. The data obtained from the sensor were compared with the spectrophotometric analyses in order to assess the anthocyanoside content. The fluorescence-based sensor used in the present study represents a rapid and non-invasive tool for assessing grape phenolic maturity and quality, and may represent in perspective an alternative to destructive laboratory analyses, which are time-consuming and require an accurate sampling approach
DNS of an oblique jet in a particle-laden crossflow: study of solid phase preferential concentration and particle-wall interaction
No full textA DNS study of the interaction between an oblique laminar jet and a particle-laden crossflow is presented. The delivery tube is included in the simulation and jet in crossflow blowing ratio is set equal to 0.5, typical for gas turbine film cooling applications. The solid phase is polydisperse and it is simulated by adopting a Lagrangian two-way coupling point-particle approach. Wall-particle interaction is also taken into account. The fluid flow in the jet outflow region was found to be dominated by a strong vorticity field and by hairpin shaped vortices that are shed periodically in the crossflow. Hairpin legs are associated to a counter-rotating vortex pair that persist in the far-field of the jet. The spatial distribution of the dispersed phase is strongly influenced by these large-scale coherent structures. A three-dimensional Voronoi analysis demonstrated a particle preferential concentration induced by hairpin vortices downstream from the jet exit. Volume fractions curves are presented as a function of the spanwise direction for different transversal sections of the crossflow region. A void particle region is induced by vortices in the central near-wall zone downstream of the jet exit. Particles tend to accumulate along two symmetric regions placed on the lateral side of the structures generated by the jet injection. By an analysis of particle impacts on the wall it was observed that particles characterized by lower values of the St number, whose response time is comparable with the characteristic time of the hairpin vortices, tend to impact on the wall on two symmetric side of the jet exit in the proximity of hairpin legs. This demonstrated that the generated large-scale coherent structures play a major role in the not homogeneous dispersion of the solid phase
Effects of water-to-air mass ratio on long-term washing efficiency and erosion risk in an axial compressor under online washing conditions
No full textOne of the main reasons for gas turbines’ performance losses is the deposition of dirt on the compressor blades. Dirt deposit has to be periodically removed to keep the engine performance as high as possible. This is the reason motivating the presence of online water washing systems in most compressor gas turbines. Such systems aim at cleaning the compressor blades to recover efficiency; thus, the larger the water flow, the better it is assumed the compressor is cleaned (fixing all the other conditions). In the present work, we simulate the long-term behavior of a real axial compressor, from the inlet to the first-stage rotor, subject to online water washing with different water flowrates. The frozen rotor approach is adopted to solve the flow field in the rotor region. Simulations are performed by using the unsteady k-ε realizable model coupled with a Lagrangian tracking of the injected liquid phase. Water droplet erosion is handled by using a semi-empirical model developed by the authors. In each simulation, 504,000 parcels have been tracked, providing statistically reliable predictions. To simulate the long-term evolution of the washing process, a discrete mesh morphing technique coupled with the use of specific scale factors is adopted. Each of the tested configurations is composed of three successive erosive steps up to the blade compressor end-of-life. By varying the water-to-air mass fraction (WAMF*), six different injection configurations are assessed in terms of long-time average washing efficiency and erosion risk. The results predicted show the dependence of the considered washing indices on water mass flowrate and set the stage for the development of a washing optimization tool, which can help the design and management processes. In scenarios where washing indices are given minimal importance and the objective is to reduce the risk of erosion, the optimal injection configuration was shown to correspond to a WAMF* value of 0.250. Conversely, when washing efficiency is prioritized, the optimal injection configuration has been shown to correspond to the case where WAMF* = 0.750
Effects of different water regimes on berry metabolism and composition of ‘Aleatico’ grapevine
No full textThis work reports the results of a trial carried out on 'Aleatico' grapevine, a cultivar cultivated along Tuscany coasts and in Elba Island, from which a typical dessert wine is produced after partial postharvest dehydration of berries. Two different water regimes were applied in the vineyard: not irrigated (water stress, WS) and partially irrigated (moderate water deficit, MWD). WS conditions determined a decrease of stem water potential (SWP) that reached values lower than - 1.4 Mpa, whereas in MWD these SWP levels were registered only for short periods. Significant differences in stomata conductance and net photosynthetic rate values were observed between the two treatments. At harvest, berry weight was reduced of about 20% in WS plants. An effect of similar magnitude was detected for skin weight, while seed weight was not affected. The sugar accumulation process was more pronounced in WS berries and this was paralleled by higher titratable acidity values both at veraison and harvest. Skin anthocyanin content was determined in laboratory and by a fluorimetric method, using the optical sensor Multiplex (R) 2, an innovative portable instrument based on chlorophyll fluorescence, that non-destructively analyzes the berries in the field, under natural light. WS induced a significant increase of anthocyanin biosynthesis as their content resulted to be higher than that of MWD samples. The cultivar 'Aleatico' appeared to be quite tolerant to water stress conditions and this information could be useful also for setting up targeted postharvest dehydration strategies to produce dessert wines. An additional interesting result is represented by the validation of the use of a portable non-destructive instrument to measure skin anthocyanin content directly in the vineyard
Physiological responses and grape quality on ‘Aleatico’ grapevine subjected to different water regimes
No full text
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
- …
