1,721,203 research outputs found
A model for color screening in a QCD plasma: the roles of thermal gluons and of confinement
No full textOrientamento e bilancio di competenze in gruppo
No full textIn questo articolo viene presentata un’esperienza di orientamento e bilancio di competenze finanziata dalla Regione del Veneto e realizzata presso Casa di Carità Arti e Mestieri di Bassano del Grappa. Vengono descritti il gruppo di partecipanti, l’organizzazione delle attività (approcci, fasi e metodi utilizzati) e le competenze messe in atto dai consulenti non solo per la progettazione e la gestione dell’intervento, ma anche per la sua valutazione, di cui si riportano i principali risultati emersi
CRONIN EFFECT AND ENERGY CONSERVATION CONSTRAINTS IN HIGH-ENERGY PROTON NUCLEUS COLLISIONS
No full textAbstract: We estimate the Cronin effect in pA collisions at the CERN LHC and at the BNL RHIC, using a Glauber-eikonal model of initial state multiparton interactions. For a correct determination of the initial parton flux, we upgrade the model cross section, taking carefully into account all kinematical constraints of each multiparton interaction process. As compared with previous results, derived with approximate kinematics, we obtain a softer spectrum of produced partons, while improving the agreement of the model with the recent measurements of pi(0) production in d+Au collisions at roots=200A GeV
XPS/ESCA on glass surfaces: A useful tool for ancient and modern materials
No full textIn the field of glass science and technology, as well as for historical glasses, a remarkable importance is devoted to the understanding of the interaction between the glass surfaces and the surrounding environment. Glass fabrication and preservation are very important issues in several research fields, involving both industrial and scientific problems. In general, a multi-technique approach should be used in order to achieve a better understanding of the complex phenomena involving reactions among glass surface atoms and environmental ones. In this frame, one of the most promising investigation technique is the X-ray photoelectron spectroscopy, XPS (also known as electron spectroscopy for chemical analysis, ESCA) mainly because of its ability to give information about the chemical bonds of the investigated atoms. In this paper the first part is devoted to the description of the basics of the technique, while in the second part several applications to the analysis of oxide glass surfaces are reported and discussed. The aim of this paper is to provide valuable help to all those who want to start or deepen the study of glass surfaces by this technique
Sociomateriality as a partner in the polyphony of students positioning
No full textIn this article, an innovative academic course, inspired by the Bakhtinian perspective and positioning theory, is presented and discussed. Within this dialogic framework, we argue that the sociomateriality of the setting cannot be considered as a separate voice because it influences the polyphony of the students' intricate positioning processes. The research context was a semester-long course on “Materiality in contexts” attended by 26 university students (6 male and 20 female), which introduced sociomaterial perspectives in education. During the course, hands-on activities were organized jointly by teachers and students, including two workshops addressed to children (aged 4–11 years) and their parents, in which the participants were involved in creating musical instruments and inventing figurines' means of transportation. The data presented in this article concern the transcriptions and analyses of three focus groups conducted at the end of the course to allow the university students to reflect about their lived experience. Through a qualitative analysis, we discuss several excerpts extracted from the focus groups to show how sociomateriality enters the polyphonic orchestration of voices concurring to define students positioning
Implanted dielectrics: synchrotron radiation studies by absorption and diffraction techniques
No full textSequential ion implantation of two elements in dielectrics, followed by thermal annealing in controlled atmosphere, gives rise to a variety of different composite materials. The formation of either metal or semiconductor binary nanoclusters is studied by synchrotron radiation-based techniques. In particular, extended X-ray absorption fine structure spectroscopy and grazing incidence X-ray diffraction give information on the role of different driving forces in determining the final composite structure. Some case studies are presented in detail, in particular, the AuCu and AuAg systems, while for the semiconductor composites some results are presented on GaN and GaAs systems. All samples are obtained by sequential implantation and thermal annealing in either reducing or oxidizing atmosphere
Fractional momentum correlations in multiparton collisions at LHC
No full textMultiple parton collisions will represent a rather common feature in pp collisions at the LHC, where regimes with very large momentum transfer may be studied and events rare in lower energy accelerators might occur with a significant rate. A reason of interest in large pt regimes is that, differently from low pt, evolution will induce correlations in x in the multiparton structure functions. We have estimated the cross section of multiple production of W bosons with equal sign, where the correlations in x induced by evolution are particularly relevant, and the cross section of View the MathML source production, where the effects of evolution are much smaller
Insights on surface analysis techniques to study glass primary packaging
Full text linkDuring the forming process of a vial by tubing glass, temperatures of up to 1200◦C are applied to adjust the glass viscosity. This process causes the release of volatile components such as alkali borates. Consequently, the percentage of sodium and boron measured on the inner surface of the vial can be higher than that measured on the corresponding glass tube. This study aimed to characterize the inner surface of two different borosilicate glass tubes of type I before and after the vial forming process at the nanoscale level. Quantitative elemental analysis of the surface along the vertical axis of glass tubes and vials was performed by X-ray photoelectron spectroscopy, whereas the topographical investigation was carried out by scanning electron microscopy (SEM). In the near-bottom region of a vial, which is usually the area most prone to corrosion, the SEM micrographs showed the appearance of bulges on the surface. The latter were then analyzed by time-of-flight secondary ion mass spectrometry to characterize their molecular composition. The purpose of this work is to identify possible new strategies for faster identification of factors that eventually influence chemical resistance of pharmaceutical glasses and to provide useful information needed to improve industrial processes
Consolidation and coating treatments for glass in the cultural heritage field: A review
Full text linkConsolidation and coating treatments are two types of interventions that form part of the active con- servation actions developed for historical and archaeological glass over the years. While thermoplastic and thermosetting resins are widely adopted by conservators worldwide, issues related to the toxicity and the material compatibility of these products remains unsolved. To address these issues, effort s have been made to develop new formulations that can functionally replace or exhibit performance advantages with respect to these canonical polymeric materials. In this review, we discuss the main classes of ma- terials applied thus far for protection and consolidation aims in the cultural heritage glass field, starting from the beginning of the 19th century and continuing until present days. We also assess the potential of hybrid organic-inorganic materials and full inorganic materials as alternative solutions to the limita- tions of organic materials in application. Finally, we provide our perspectives on future directions for the development of consolidation products that meet the specific requirements of the cultural heritage field
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