282 research outputs found

    Stiffening effects-controlling sizing procedure of ADAS dampers in seismic retrofit of frame structures

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    Added Damping and Stiffness (ADAS) steel dissipators are among the most classical devices installed in dissipative bracing systems for the advanced seismic retrofit of frame buildings. An energy-based sizing procedure is formulated in this study for this class of dampers, where the total number of constituting plates is directly related, without iterative steps, to the supplementary damping energy required to jointly reduce stress states in structural members and storey drifts. The stiffening effects of the dissipative braces are expressly controlled, so as to compensate for the increase in storey shears induced by their incorporation in the frame skeleton. The sizing procedure is demonstratively applied to the retrofit design of a 6-storey reinforced concrete building, to explicate and discuss the use of its analytical relations and relevant limitations in practice. The evaluation of the seismic performance of the structure in retrofitted conditions allows comparing the response of the dissipative bracing system with the hypotheses formulated at the sizing stage

    A case study of modern heritage building: Base isolation seismic retrofit for preservation of its architectural distinguishing features

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    Several Italian buildings designed by eminent architects and structural engineers in the second half of the 20th century are now included in modern heritage listings. At the same time, as they were designed before the issue of coordinate national Technical Standards, often require important structural rehabilitation interventions. One of the most representative case studies of that period in Florence, i.e. the building now housing the Automobile Club Headquarter and a B&B Hotel, is examined in this paper. A seismic assessment analysis carried out on the structure highlighted strength deficiencies in several members and potentially severe pounding conditions between the two constituting wings of the building, separated by a narrow technical gap. In order to improve the seismic performance without altering the architectural appearance of the building, characterized by large windows in the fa\ue7ades, free internal spaces and elegant proportions of the main structural members, a base isolation retrofit hypothesis is proposed. A substantial seismic improvement is obtained in rehabilitated conditions, as assessed by the achievement of safe stress states for all members up to the basic design normative earthquake level, as well as of maximum relative lateral displacements of the two wings constrained below the technical gap width

    Repeatability of the ISAAC video questionnaire and its accuracy against a clinical diagnosis of asthma

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    AbstractThe objective of the study was to evaluate the performance of the International Study of Asthma and Allergies in Childhood (ISAAC) video questionnaire in terms of repeatability and accuracy against a clinical diagnosis of asthma achieved according to the National Heart, Lung and Blood Institute (NHLBI) algorithm.Two hundred and forty-one subjects, aged 13–14 years from two secondary schools in Rome, Italy, were enrolled. Video and written ISAAC questionnaires were completed twice, 3 months apart, by 194 and 190 adolescents, respectively. Two months later, 106 subjects were visited by two physicians blinded to the results of questionnaires.Sixteen subjects were classified as having clinical asthma (CA) at the clinical visit, and eight of them as having clinical active asthma (CAA) on the basis of at least one positive outcome of the NHLBI algorithm. The repeatability of video questionnaire was similar to that of the written questionnaire for items on exercise wheeze and nocturnal cough and, to a lesser degree, for items concerning any wheeze in the past. The video questionnaire showed a worse performance than the written questionnaire for items on asthma attack: K-value (95% CL)=0·59 (0·37–0·80) for video scene no. 5 and K-value (95% CL)=0·86 (0·74–0·98) for written question no. 6. The overall accuracy of the video questionnaire, estimated as a positive answer to any video scene, was lower in terms of sensitivity than that of any written question when CA was used as a gold standard (0·50 vs. 0·81, P=0·025) and increased with respect to CAA (0·75vs. 0·87, P=0·317). The specificity of any video scene was better than that of any written question, independently from the gold standard used.In conclusion, the video questionnaire showed a fairly good accuracy, although slightly lower than that of the written questionnaire and provided sufficiently reliable results. However, samples of subjects from different geographic areas and cultures should be studied in order to conclusively define the performance of the ISAAC video questionnaire

    Assessing whether artificial intelligence is an enabler or an inhibitor of sustainability at indicator level

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    "Since the early phase of the artificial-intelligence (AI) era expectations towards AI are high, with experts believing that AI paves the way for managing and handling various global challenges. However, the significant enabling and inhibiting influence of AI for sustainable development needs to be assessed carefully, given that the technology diffuses rapidly and affects millions of people worldwide on a day-to-day basis. To address this challenge, a panel discussion was organized by the KTH Royal Institute of Technology, the AI Sustainability Center and MIT Massachusetts Institute of Technology, gathering a wide range of AI experts. This paper summarizes the insights from the panel discussion around the following themes: The role of AI in achieving the Sustainable Development Goals (SDGs) AI for a prosperous 21st century Transparency, automated decision-making processes, and personal profiling and Measuring the relevance of Digitalization and Artificial Intelligence (D&AI) at the indicator level of SDGs. The research-backed panel discussion was dedicated to recognize and prioritize the agenda for addressing the pressing research gaps for academic research, funding bodies, professionals, as well as industry with an emphasis on the transportation sector. A common conclusion across these themes was the need to go beyond the development of AI in sectorial silos, so as to understand the impacts AI might have across societal, environmental, and economic outcomes. The recordings of the panel discussion can be found at: https://www.kth.se/en/2.18487/evenemang/the-role-of-ai-in-achieving-the-sdgs-enabler-or-inhibitor-1.1001364?date=2020â 08â 20&length=1&orglength=185&orgdate=2020â 06â 30 Short link: https://bit.ly/2Kap1tE © 2021"The authors acknowledge the KTH Sustainability Office and the KTH Digitalization Platform for their provided funding, which enabled the organization of this panel discussion. SG acknowledges the funding provided by the German Federal Ministry for Education and Research (BMBF) for the project “digitainable”. SDL acknowledges support through the Spanish Governmen

    Quantitative evaluation of CFTR pre-mRNA splicing dependent on the (TG)mTn poly-variant tract

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    Genetic analysis in cystic fibrosis (CF) is a difficult task. Within the many causes of variability and uncertainty, a major determinant is poor knowledge of the functional effect of most DNA variants of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. In turn, knowledge of the effect of a CFTR variant has dramatic diagnostic, prognostic and, in the era of CF precision medicine, also therapeutic consequences. One of the most challenging CFTR variants is the (TG)mTn haplotype, which has variable functional effect and controversial clinical consequences. The exact quantification of the anomalous splicing of CFTR exon 10 (in the HGVS name; exon 9 in the legacy name) and, consequently, of the residual wild-type functional CFTR mRNA, should be mandatory in clinical assessment of patients with potentially pathological haplotype of this tract. Here, we present a real time-based assay for the quantification of the proportion of exon 10+/exon 10- CFTR mRNA, starting from nasal brushing. Our assay proved rapid, economic and easy to perform. Specific primers used for this assay are either disclosed or commercially available, allowing any laboratory to easily perform it. A simplified analysis of the data is provided, facilitating the interpretation of the results. This method helps to enhance the comprehension of the genotype- phenotype relationship in CF and CFTR-related disorders (CFTR-RD), crucial for the diagnosis, prognosis and personalized therapy of CF

    Effect of the rearing substrate on total protein and amino acid composition in black soldier fly

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    Insects are becoming increasingly relevant as protein sources in food and feed. The Black Soldier Fly (BSF) is one of the most utilized, thanks to its ability to live on many leftovers. Vegetable processing industries produce huge amounts of by-products, and it is important to efficiently rear BSF on different substrates to assure an economical advantage in bioconversion and to overcome the seasonality of some leftovers. This work evaluated how different substrates affect the protein and amino acid content of BSF. BSF prepupae reared on different substrates showed total protein content varying between 35% and 49% on dry matter. Significant lower protein contents were detected in BSF grown on fruit by-products, while higher contents were observed when autumnal leftovers were employed. BSF protein content was mainly correlated to fibre and protein content in the diet. Among amino acids, lysine, valine and leucine were most affected by the diet. Essential amino acids satisfied the Food and Agricultural Organization (FAO) requirements for human nutrition, except for lysine in few cases. BSF could be a flexible tool to bio-convert a wide range of vegetable by-products of different seasonality in a high-quality protein-rich biomass, even if significant differences in the protein fraction were observed according to the rearing substrate

    Photoionization of ultracold and Bose-Einstein condensed Rb atoms

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    Photoionization of a cold atomic sample offers intriguing possibilities to observe collective effects at extremely low temperatures. Irradiation of a rubidium condensate and of cold rubidium atoms within a magneto-optical trap with laser pulses ionizing through 1-photon and 2-photon absorption processes has been performed. Losses and modifications in the density profile of the remaining trapped cold cloud or the remaining condensate sample have been examined as function of the ionizing laser parameters. Ionization cross-sections were measured for atoms in a MOT, while in magnetic traps losses larger than those expected for ionization process were measured.Comment: 9 pages, 7 figure

    Local mechanical properties of electrospun fibers correlate to their internal nanostructure.

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    This is the final version of the article. Available from the publisher via the DOI in this record.The properties of polymeric nanofibers can be tailored and enhanced by properly managing the structure of the polymer molecules at the nanoscale. Although electrospun polymer fibers are increasingly exploited in many technological applications, their internal nanostructure, determining their improved physical properties, is still poorly investigated and understood. Here, we unravel the internal structure of electrospun functional nanofibers made by prototype conjugated polymers. The unique features of near-field optical measurements are exploited to investigate the nanoscale spatial variation of the polymer density, evidencing the presence of a dense internal core embedded in a less dense polymeric shell. Interestingly, nanoscale mapping the fiber Young's modulus demonstrates that the dense core is stiffer than the polymeric, less dense shell. These findings are rationalized by developing a theoretical model and simulations of the polymer molecular structural evolution during the electrospinning process. This model predicts that the stretching of the polymer network induces a contraction of the network toward the jet center with a local increase of the polymer density, as observed in the solid structure. The found complex internal structure opens an interesting perspective for improving and tailoring the molecular morphology and multifunctional electronic and optical properties of polymer fibers.V. Fasano and G. Potente are acknowledged for confocal and SEM images, respectively. The authors also gratefully thank S. Girardo for high-speed imaging of the polymer jet and E. Caldi for assistance in the SNOM measurements. We gratefully acknowledge the financial support of the United States-Israel Binational Science Foundation (BSF Grant 2006061), the RBNI-Russell Berrie Nanotechnology Institute, and the Israel Science Foundation (ISF Grant 770/11). The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306357 (ERC Starting Grant “NANO-JETS”)
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