1,721,093 research outputs found
Structure of Non-Crystalline Materials 12 Proceedings of the 12th International Conference on the Structure of Non-Crystalline Materials (NCM12), Riva del Garda-Trento, Italy July 7-13, 2013
No full textProceedings of NCM12
12th International Conference on the Structure of Non-Crystalline Materials (NCM12), Riva del Garda-Trento, Italy July 7-13, 201
Electronic structure effects on B K-edge XANES of minerals
No full textIn order to assess the usability of X-ray absorption near-edge structure (XANES) for studying the structure of BOn-containing materials, the dependence of theoretical XANES at the B K-edge on the way the scattering potential is constructed is investigated. Real-space multiple-scattering calculations are performed for self-consistent and non-self-consistent potentials and for different ways of dealing with the core hole. It is found that in order to reproduce the principal XANES features it is sufficient to use a non-self-consistent potential with a relaxed and screened core hole. Employing theoretical modelling of XANES for studying the structure of boron-containing glasses is thus possible. The core hole affects the spectrum significantly, especially in the pre-edge region. In contrast to minerals, B K-edge XANES of BPO4 can be reproduced only if a self-consistent potential is employed. (C) 2010 International Union of Crystallography Printed in Singapore - all rights reserve
The 12th International Conference on the Structure of Non-Crystalline Materials (NCM12), Riva del Garda-Trento, Italy July 7–13, 2013
No full textIntroduzione al Volume dei Proceedings, con illustrazione del Congresso NCM12 da parte degli Editors
La parametrazione delle quantità fisiche nella definizione dei costi parametrici Il Decreto 50/2016 sulla progettazione delle opere pubbliche
No full textIl presente contributo intende aprire un dibattito alla luce del nuovo codice degli appalti (art. 23 Dlgs 50/2016) sui ruoli del progettista, del pianificatore e del valutatore e sul nuovo progetto di fattibilità tecnica ed economica, con lo scopo di individuare nuovi paradigmi nel campo della progettazione ingegneristica ed architettonica.
Il nuovo codice ha portato un’importante innovazione, ovvero il progetto di fattibilità tecnica ed economica, che ha sostituito il progetto preliminare e lo studio di fattibilità, ulteriormente rafforzato da aspetti qualitativi, tecnici ed economici.
Se in passato vi era la necessità di valutare il costo di realizzazione dell’opera sin dallo studio di fattibilità per fornire l’indispensabile copertura finanziaria all’intervento, oggi risulta altrettanto fondamentale la messa in condizione del committente di poter scegliere la migliore soluzione progettuale sulla base dell’ individuazione e selezione di una serie di alternative.
Oggi più che in passato, la carenza di dati storici e la difficoltà di adeguamento del costo dell’opera alle caratteristiche peculiari dell’oggetto hanno portato ad un’eccessiva semplificazione della stima, spesso trascurando le economie di scala del contesto di riferimento e con conseguenze facilmente immaginabili. Affinché i principi della predetta modifica legislativa non rimangano delle mere enunciazioni, appare necessario ribadire l’importanza della costruzione delle alternative, del processo delle scelte e dei criteri di valutazione delle alternative, per tutti gli interventi, pubblici e privati, per opere a rete e puntuali. Un notevole apporto positivo sarebbe potuto giungere dalla divulgazione dei costi standard, per cui era deputato l’Osservatorio dei lavori pubblici a oggi mai avvenuta.The purpose of the contribution is to open a debate aiming to identify, considering the new Public Procurement Code (Article 23 Legislative Decree n. 50/2016) which introduces the technical and economic feasibility, the role of the designer, of the planner and of the evaluator. An important innovation came with the introduction of art. 23 of the Legislative Decree n. 50/2016 (in this document Dlgs n. 50/2016). Thanks to this new regulation, the technical and economic feasibility project (replacing the preliminary draft and feasibility study) is further strengthened with regard to the technical and economic quality aspects. In order to prevent that the principles of the aforementioned regulation remain mere enunciations, it is necessary to define the construction of alternatives, the process of choices and the criteria for the evaluation of alternatives. Yesterday, starting from the feasibility study even if in an indicative way, the only need was to know the realizing cost of the work to provide the necessary financial coverage of the intervention. Today in addition, the costumer of the work needs to choose the best design solution based on the definition and selection of alternatives. Nowadays, more than in the past, the shortage of historical data and the difficulty of adjusting cost to peculiar features, often neglecting the possibility to consider economies of scale of their context, have led to excessive simplification of estimation with adverse consequences that can easily be imagined. It is worth remembering that the need for parametric estimations, both for public and private, for network works and punctuation ones, is increasingly emphasized, and is also divided into a number of typologies that can be used for the same building and for all intended use. Although influential, the DEI bulletin of the College of Architects and Engineers of Milan, which reports about 60 records of new constructions to be used as reference prices, is poorly adapted to respond to the variety of estimation queries. This shows clearly the need for an up-to-date database with a broad set of benchmark prices that it should be able to use for such diverse interventions. The bulletin is not enough to cover the requirements for the ex-ante cost analysis during technical and economic feasibilit y. A remarkable positive contribution could have come from the publication of standard costs, considered as a measure of what the cost should be. The Public Works Observatory (Osservatorio dei lavori pubblici) had been charged with drafting a proposal but nowadays in Italy any standardization has not been proposed yet. The contribution also contains the first contents of a research that is being carried out with regard to the determination of significant indicators for the economic and qualitative assessment of residential interventions
Monoclonal antibodies in newly diagnosed and smoldering multiple myeloma: an updated review of current clinical evidence
No full textIntroduction: Monoclonal antibodies (MoAbs) are rapidly changing the therapeutic scenario of multiple myeloma. Most of the available data, however, come from studies performed in patients with relapsed or refractory disease. Area covered: Here, the most recent results from clinical trials that have investigated (or are investigating) efficacy and safety of MoAbs as front-line treatments in both transplant-eligible and not-eligible patients with newly diagnosed multiple myeloma, as well as in smoldering myeloma, are reviewed. PubMed reported articles before 28 March 2020, and abstracts presented at the last ASCO, ASH, EHA, and IMW meetings were considered. Among others, pertinent data regarding daratumumab, isatuximab, elotuzumab, and pembrolizumab will be analyzed. Expert opinion: Introduction of MoAbs as first-line therapy will likely provide a significant improvement in the clinical outcome of patients with multiple myeloma. This will also require an appropriate re-positioning of salvage therapies. The role of MoAbs in smoldering myeloma appears to be promising, but adequate follow-up is needed
XRD and EXAFS studies on the structure of Er3+-doped SiO2-HfO2 glass-ceramic waveguides: Er3+-activated HfO2 nanocrystals
No full textX-ray absorption spectroscopy studies of glass structure
No full textIn the last few decades, X-ray Absorption Spectroscopy (XAS) has recorded a remarkable amount of interest in the study of glass structure for its sensitivity to the Short Range Order (SRO) around a selected atomic species. XAS greatest evolution started in the seventies of the last century thanks to an adequate and structurally useful theoretical interpretation of the Extended X-ray Absorption Fine Structure (EXAFS) beyond the absorption edge and to the contemporaneous advent of synchrotron radiation facilities. EXAFS probes the local structure of liquid, vitreous, amorphous, and crystalline materials; it is particularly important for noncrystalline systems since they do not give rise to the Bragg diffraction. EXAFS is also used to determine the local environment of impurities contained in glasses, even if they are very diluted. Today, a reliable theoretical description of glassy system structure through modern modelling techniques should be carried out on the basis of x-ray and/or neutron scattering patterns, along with a careful use of the information derived from SRO techniques like EXAFS, NMR, etc. The use of EXAFS in the case of nanocrystalline glass-ceramic systems is very important, since the obtained information are complemental to the ones determined by the Bragg diffraction. The paper gives a brief description of EXAFS theory and analysis methods in the case of disordered systems. Examples of state-of-the-art studies in different glassy systems will be presented along with a critical assessment of EXAFS potential for such systems
On the origin of the differences in the Cu K-edge XANES of isostructural and isoelectronic compounds
No full textCu K-edge x-ray absorption near-edge structure (XANES) spectra of trigonal (3R) CuScO2 and CuLaO2 and of hexagonal (2H) CuScO2 were investigated experimentally and theoretically, in order to study differences between spectra of isostructural and isoelectronic compounds. Significant differences were found in the Cu K-edge XANES of 3R CuScO2 and 3R CuLaO2; these differences can be understood by considering the calculated polarization dependence of the XANES spectra and the differences between the phaseshifts of Sc and La. Spectra of the 3R and 2H polytypes of CuScO2 differ only weakly and the difference originates from the long-range order. The pre-edge peak around 8980 eV is generated by the same mechanism as the pre-edge peak in Cu2O, i.e. involving scattering by the Cu atoms in the plane which is perpendicular to the O-Cu-O axis
Ordered and disordered models of local structure around Ag cations in silver borate glasses based on x-ray absorption near-edge structure spectroscopy
No full textThe local coordination of Ag cations in silver borate glasses Ag2O.nB(2)O(3) has been studied by comparing the experimental x-ray absorption near edge structure (XANES) at the Ag K edge with results of theoretical simulations. We demonstrate that simple models which describe the local structure around Ag with a single geometric configuration cannot be reconciled with experimental XANES spectra. In order to obtain a satisfactory agreement between theory and experiment, it is necessary to include the disorder also at the short range. Structural information is extracted from XANES data using an empirical approach, which is based on the presence of a multiplicity of atomic structural configurations around photoabsorbing atoms. This approach is particularly suited for describing the local environment of atomic species belonging to glass network modifiers
Zn K edge and O K edge x-ray absorption spectra of ZnO surfaces: implications for nanorods
No full textZn K edge and O K edge x-ray absorption near-edge structure (XANES) spectra of ZnO surfaces are calculated. The difference between theoretical XANES for ZnO surfaces and ZnO bulk is then compared to the earlier observed differences between experimental XANES for ZnO nanostructures and ZnO bulk as taken from the literature. It follows from our calculations that the differences between the experimental XANES of bulk ZnO and nanocrystalline ZnO is not due to the enhanced role of the surfaces in nanostructures. Rather, the difference in XANES has to reflect differences in the local geometry around the photoabsorbing sites. The dependence of XANES of ZnO surfaces on the polarization of the incoming radiation is also investigated theoretically and found to be similar as in the bulk
- …
