1,721,012 research outputs found
Multi-wavelengths 3D laser scanner for investigation and reconstruction of 19th century charcoal inscriptions
No full textDigital reconstruction is nowadays a widespread practise and, at the same time, a useful tool in CH field, starting from the study of works of art up to the delineation of conservation actions. The present work describes the use of the ENEA 3D laser scanner prototype, called RGB-ITR, for a deepen investigation of 19th century charcoal inscriptions on wall drawings, placed in the Saint Sebastian Door of the monumental Aurelian Walls (Rome), with the aim of understanding the historical value. The results of post-processing analysis of the high detailed 3D models with properly-developed algorithms allowed the preliminary reconstruction of the contents, demonstrating the value of the adopted technique for 3D digitalization of the room thanks to its features, such as independence from variable lighting conditions, acquisitions at great distances and no need of area interdiction or scaffolds
Laser-Induced Breakdown Spectroscopy Applied on Liquid Films: Effects of the Sample Thickness and the Laser Energy on the Signal Intensity and Stability
Full text linkDroplets of organic liquids on aluminum substrate were probed by an Nd:YAG laser, both in a steady state and during rotation at speeds 18–150 rpm. Rotation transforms the droplet into film, which estimated thickness at high speeds was below 3 μm and 20 μm for diesel and peanut oil, respectively. Line intensities from the liquid (C I) and the support (Al I) material were tracked as a function of the film thickness and the laser energy. By film thinning, the line intensities from liquid sample were enhanced up to a factor 100x; simultaneously, the LIBS signal fluctuations were reduced 5–10 times with respect to the steady droplet. In certain experimental conditions, the line intensities from the support material become very weak with respect to the C I line, indicating an efficient screening of the substrate by highly excited plasma from the liquid layer. At a fixed rotation speed, there is a laser energy threshold, dependent on the liquid thickness, above which the LIBS signal becomes stable. Here, we discuss the relative processes and optimization of the experimental conditions for the LIBS measurements frome one laser shot to another
Caratterizzazione dei meccanismi di assorbimento e assimilazione dello S in piante di frumento Fe-carenti
No full textChanges in S assimilation pathway in response to S and Fe deficiency stress in wheat seedlings
No full textThe Importance of Artworks 3D Digitalization at the Time of COVID Epidemy: Case Studies by the Use of a Multi-wavelengths Technique
Full text linkAt the moment when this article is written, a pandemic disease is attacking our lives, our style of living and our economy. The present work uses this occasion for focusing the attention on the importance to make available a digital copy of our knowledge, history and habits. The slower passing of time inside own residence let the individual to rediscover natural indoor activities, like reading a book or watching a documentary, and try to mentally escape by a virtual visit in a museum or a city. The first evidence coming out from these sites is mainly the limits of this technology for appreciating the artworks, even inside 3D environments, and, probably the most important, the lack of standardization in terms of accessibility and quality of the products. The present work focuses the attention only on one of the aspects of the processes for studying and documenting an artwork: the data acquisition and preprocessing data fusion. For approaching these steps, an out-of-the-market 3D technology based on the combination of several laser sources will be described: the description of this kind of systems is the pretext for analyzing the main differences with the available devices and techniques today largely used in Cultural Heritage environment, but especially for highlighting how the research can try to unify the gamification with diagnostic and restoration support in this sector
Sample Preparation for Repeated Measurements on a Single Liquid Droplet Using Laser-Induced Breakdown Spectroscopy
No full textWe studied changes in laser-induced breakdown spectroscopy (LIBS) signal intensity with the thickness of a liquid layer placed on a solid substrate, where an easily evaporating methanol sample was used. For a certain optimal liquid film thickness we obtained a manifold increase of the LIBS signal from methanol. Progressive liquid film thinning leads to a reduction and a successive disappearance of laser-induced splashes; the latter condition drastically reduces the sample consumption and allows measurements to be repeated many times on a single liquid droplet. In following, we developed two methods for actively controlled deformation, i.e., thinning of a liquid droplet (volume -1/410 μl) prior to its sampling by LIBS. Control of the droplet's height was achieved on a Si-SiO2 wafer substrate by electro-wetting in the case of water solutions or by target rotation in the case of viscous liquids. The chosen substrate also has the advantages of low cost, easy manipulation, and very high purity, thus minimizing interference with analytes. Through the droplet deformation, in a single-pulse excitation at moderate laser energy (70 mJ), we clearly detected Fe and Mn in peanut oil, which represent trace elements in edible oils (-1/4 1 part per billion), according to results published in the literature. © Society for Applied Spectroscopy
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
Iron deprivation results in a rapid but not sustained increase of the expression of genes involved in iron metabolism and sulfate uptake in tomato (Solanum lycopersicum L.) seedlings
No full textCharacterization of the relationship between sulfur and iron in both Strategy I and Strategy II plants, has proven that low sulfur availability often limits plant capability to cope with iron shortage. Here it was investigated whether the adaptation to iron deficiency in tomato (Solanum lycopersicum L.) plants was associated with an increased root sulfate uptake and translocation capacity, and modified dynamics of total sulfur and thiols accumulation between roots and shoots. Most of the tomato sulfate transporter genes belonging to Groups 1, 2, and 4 were significantly upregulated in iron-deficient roots, as it commonly occurs under S-deficient conditions. The upregulation of the two high affinity sulfate transporter genes, SlST1.1 and SlST1.2, by iron deprivation clearly suggests an increased root capability to take up sulfate. Furthermore, the upregulation of the two low affinity sulfate transporter genes SlST2.1 and SlST4.1 in iron-deficient roots, accompanied by a substantial accumulation of total sulfur and thiols in shoots of iron-starved plants, likely supports an increased root-to-shoot translocation of sulfate. Results suggest that tomato plants exposed to iron-deficiency are able to change sulfur metabolic balance mimicking sulfur starvation responses to meet the increased demand for methionine and its derivatives, allowing them to cope with this stress. © 2013 Institute of Botany, Chinese Academy of Sciences
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
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