36 research outputs found

    Polar Wax as Adhesion Promoter in Polymeric Blend Films for Durable Photovoltaic Encapsulants

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    Technological developments in the solar photovoltaic field must guarantee the high performance and low deterioration of solar cells in order for solar power plants to be more efficient and competitive. The solar cell needs comprehensive protection offered by a polymeric encapsulant, which improves UV stability, reduces water and moisture absorption, reduces oxygen and vapor permeability and enhances mechanical resistance. Moreover, high transparency and adhesion yields improved the solar panel performance. The current work analyzes polymeric films based on poly(ethylene-co-vinyl acetate) (EVA) and polyolefin (PO) for photovoltaic encapsulant use (the high temperature resistance is improved by adding PO to EVA, as investigated and documented before). To enhance the mechanical resistance and optical properties of the investigated matrices, a crosslinking agent, an adhesion promoter and stabilizing agents have been incorporated in both EVA and EVA/PO systems. The adhesion promoter is a polar wax–silane-free agent; the absence of the silane function allows the integrity of the module to be maintained over time. All samples were characterized through mechanical and rheological analysis, and their long-term UV stability was investigated by accelerated ageing and by FTIR and UV–vis spectroscopy. The obtained results suggest that the presence of a crosslinking agent, an adhesion promoter and stabilizers in EVA/PO-based films allows for the achievement of the required features for the encapsulants, showing mechanical and rheological behavior similar to those of EVA containing the same additives

    Modelling the Frequency of Interarrival Times and Rainfall Depths with the Poisson Hurwitz-Lerch Zeta Distribution

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    The Poisson-stopped sum of the Hurwitz-Lerch zeta distribution is proposed as a model for interarrival times and rainfall depths. Theoretical properties and characterizations are investigated in comparison with other two models implemented to perform the same task: the Hurwitz-Lerch zeta distribution and the one inflated Hurwitz-Lerch zeta distribution. Within this framework, the capability of these three distributions to fit the main statistical features of rainfall time series was tested on a dataset never previously considered in the literature and chosen in order to represent very different climates from the rainfall characteristics point of view. The results address the Hurwitz-Lerch zeta distribution as a natural framework in rainfall modelling using the additional random convolution induced by the Poisson-stopped model as a further refinement. Indeed the Poisson contribution allows more flexibility and depiction in reproducing statistical features, even in the presence of very different climates

    Plant communities and landscape diversity in NW Sicily: The MEMOLA EU FP7 Project case study

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    The MEMOLA EU FP7 Project case study\u201d was presented at IV International Plant Science Conference (IPSC) held in Parma (Italy) on September 20-22, 2017. The poster focuses on the contribution of botany in the interdisciplinary debate of Memola Project and underline the role plant communities play in understanding the formative processes of the Mediterranean Landscapes

    PEER Testbed Study on a Laboratory Building: Exercising Seismic Performance Assessment

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    From 2002 to 2004 (years five and six of a ten-year funding cycle), the PEER Center organized the majority of its research around six testbeds. Two buildings and two bridges, a campus, and a transportation network were selected as case studies to “exercise” the PEER performance-based earthquake engineering methodology. All projects involved interdisciplinary teams of researchers, each producing data to be used by other colleagues in their research. The testbeds demonstrated that it is possible to create the data necessary to populate the PEER performancebased framing equation, linking the hazard analysis, the structural analysis, the development of damage measures, loss analysis, and decision variables. This report describes one of the building testbeds—the UC Science Building. The project was chosen to focus attention on the consequences of losses of laboratory contents, particularly downtime. The UC Science testbed evaluated the earthquake hazard and the structural performance of a well-designed recently built reinforced concrete laboratory building using the OpenSees platform. Researchers conducted shake table tests on samples of critical laboratory contents in order to develop fragility curves used to analyze the probability of losses based on equipment failure. The UC Science testbed undertook an extreme case in performance assessment—linking performance of contents to operational failure. The research shows the interdependence of building structure, systems, and contents in performance assessment, and highlights where further research is needed. The Executive Summary provides a short description of the overall testbed research program, while the main body of the report includes summary chapters from individual researchers. More extensive research reports are cited in the reference section of each chapter

    Moving Toward a Strategy for Addressing Climate Displacement of Marine Resources: A Proof-of-Concept

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    Realistic predictions of climate change effects on natural resources are central to adaptation policies that try to reduce these impacts. However, most current forecasting approaches do not incorporate species-specific, process-based biological information, which limits their ability to inform actionable strategies. Mechanistic approaches, incorporating quantitative information on functional traits, can potentially predict species- and population-specific responses that result from the cumulative impacts of small-scale processes acting at the organismal level, and can be used to infer population-level dynamics and inform natural resources management. Here we present a proof-of-concept study using the European anchovy as a model species that shows how a trait-based, mechanistic species distribution model can be used to explore the vulnerability of marine species to environmental changes, producing quantitative outputs useful for informing fisheries management. We crossed scenarios of temperature and food to generate quantitative maps of selected mechanistic model outcomes (e.g., Maximum Length and Total Reproductive Output). These results highlight changing patterns of source and sink spawning areas as well as the incidence of reproductive failure. This study demonstrates that model predictions based on functional traits can reduce the degree of uncertainty when forecasting future trends of fish stocks. However, to be effective they must be based on high spatial- and temporal resolution environmental data. Such a sensitive and spatially explicit predictive approach may be used to inform more effective adaptive management strategies of resources in novel climatic conditions

    Moving Toward a Strategy for Addressing Climate Displacement of Marine Resources: A Proof-of-Concept

    Get PDF
    Realistic predictions of climate change effects on natural resources are central to adaptation policies that try to reduce these impacts. However, most current forecasting approaches do not incorporate species-specific, process-based biological information, which limits their ability to inform actionable strategies. Mechanistic approaches, incorporating quantitative information on functional traits, can potentially predict species- and population-specific responses that result from the cumulative impacts of small-scale processes acting at the organismal level, and can be used to infer population-level dynamics and inform natural resources management. Here we present a proof-of-concept study using the European anchovy as a model species that shows how a trait-based, mechanistic species distribution model can be used to explore the vulnerability of marine species to environmental changes, producing quantitative outputs useful for informing fisheries management. We crossed scenarios of temperature and food to generate quantitative maps of selected mechanistic model outcomes (e.g., Maximum Length and Total Reproductive Output). These results highlight changing patterns of source and sink spawning areas as well as the incidence of reproductive failure. This study demonstrates that model predictions based on functional traits can reduce the degree of uncertainty when forecasting future trends of fish stocks. However, to be effective they must be based on high spatial- and temporal resolution environmental data. Such a sensitive and spatially explicit predictive approach may be used to inform more effective adaptive management strategies of resources in novel climatic conditions

    Outcomes of minimally invasive partial nephrectomy among very elderly patients: Report from the resurge collaborative international database

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    The aim of the study was to perform a comprehensive investigation of clinical outcomes of robot-assisted partial nephrectomy (RAPN) or laparoscopic partial nephrectomy (LPN) in elderly patients presenting with a renal mass.The REnal SURGery in Elderly (RESURGE) collaborative database was queried to identify patients aged 75 or older diagnosed with cT1-2 renal mass and treated with RAPN or LPN. Study outcomes were: overall complications (OC); warm ischemia time (WIT) and 6-month estimated glomerular filtration rate (eGFR); positive surgical margins (PSM), disease recurrence (REC), cancer-specific mortality (CSM) and other-cause mortality (OCM). Descriptive statistics, Kaplan-Meier, smoothed Poisson plots and logistic and linear regression models (MVA) were used.Overall, 216 patients were included in this analysis. OC rate was 34%, most of them being of low Clavien grade. Median WIT was 17 minutes and median 6-month eGFR was 54 ml/min/1.73 m(2). PSM rate was 5%. After a median follow-up of 20 months, the 5-year rates of REC, CSM and OCM were 4, 4 and 5%, respectively. At MVA predicting perioperative morbidity, RAPN relative to LPN (odds ratio [OR] 0.33; p <0.0001) was associated with lower OC rate. At MVA predicting functional outcomes, RAPN relative to LPN was associated with shorter WIT (estimate [EST]-4.09; p <0.0001), and with higher 6-month eGFR (EST 6.03; p = 0.01).In appropriately selected patients with small renal masses, minimally-invasive PN is associated with acceptable perioperative outcomes. The use of a robotic approach over a standard laparoscopic approach can be advantageous with respect to clinically relevant outcomes, and it should be preferred when available

    Turbulence in Rivers

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    The study of turbulence has always been a challenge for scientists working on geophysical flows. Turbulent flows are common in nature and have an important role in geophysical disciplines such as river morphology, landscape modeling, atmospheric dynamics and ocean currents. At present, new measurement and observation techniques suitable for fieldwork can be combined with laboratory and theoretical work to advance the understanding of river processes. Nevertheless, despite more than a century of attempts to correctly formalize turbulent flows, much still remains to be done by researchers and engineers working in hydraulics and fluid mechanics. In this contribution we introduce a general framework for the analysis of river turbulence. We revisit some findings and theoretical frameworks and provide a critical analysis of where the study of turbulence is important and how to include detailed information of this in the analysis of fluvial processes. We also provide a perspective of some general aspects that are essential for researchers/ practitioners addressing the subject for the first time. Furthermore, we show some results of interest to scientists and engineers working on river flows

    Natural phenolic compounds: Anti-oxidants or pro-oxidants for biopolyesters?

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    In this work, different naturally occurring phenolic compounds, such as Thymol (Th), Vanillic acid (VA) and Ferulic Acid (FA), have been considered as UV stabilizers against the photo-oxidative degradation of polylactic acid (PLA). Particularly, in order to explore the effectiveness of the naturally occurring stabilizers, thin PLA-based films, containing different amount of the stabilizers, have been formulated and subjected to accelerate UVB exposure. The preliminary characterizations suggest that the all considered stabilizers exert a plasticizing action and the overall crystallinity of the samples is slightly reduced. If the considered stabilizers are added at low concentration, they exert a protection action, but if their content overcome a specific threshold, are able to exert a pronounced pro-degradation action. Overall, in this work, the concentration-dependent anti-/pro- oxidant activity of used naturally occurring phenolic compounds has been accurately investigated and reported
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