198 research outputs found

    On a class of hyperbolic systems with multiple characteristics

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    modeling small scale solar powered orc unit for standalone application

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    When the electricity from the grid is not available, the generation of electricity in remote areas is an essential challenge to satisfy important needs. In many developing countries the power generation from Diesel engines is the applied technical solution. However the cost and supply of fuel make a strong dependency of the communities on the external support. Alternatives to fuel combustion can be found in photovoltaic generators, and, with suitable conditions, small wind turbines or microhydroplants. The aim of the paper is to simulate the power generation of a generating unit using the Rankine Cycle and using refrigerant R245fa as a working fluid. The generation unit has thermal solar panels as heat source and photovoltaic modules for the needs of the auxiliary items (pumps, electronics, etc.). The paper illustrates the modeling of the system using TRNSYS platform, highlighting standard and "ad hoc" developed components as well as the global system efficiency. In the future the results of the simulation will be compared with the data collected from the 3 kW prototype under construction in the Tuscia University in Italy

    A comparison between preference judgments of curvature and sharpness in architectural façades

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    Can curvature drive preference, perceived familiarity, complexity, stability and approachability for architectural façades? In this study, we generated four versions of the same reference building, varying only the amount of curvature introduced in the façade. Participants’ judgments were measured using three experimental methodologies. Multidimensional scaling on forced choices showed that the curved façade was the most preferred. Multidimensional unfolding on ranking task showed that the majority of participants expressed higher preferences for the curved façade compared to the sharp-angled and rectilinear ones. Ratings on different psychological variables provided supporting evidence for curvature significantly influencing liking and approachability judgments. Results from image analyses –using a dynamical model of the visual cortex and a model that characterizes discomfort in terms of adherence to the statistics of natural images – matched behavioural data. We discuss the implications of the findings on our understanding of human preferences, which are intrinsically dynamic and influenced by context and experience.PostprintPeer reviewe

    Chemical Composition and Anti-Candida Activity of Mentha suaveolens Ehrh. Essential Oils Obtained by Different Distillation Processes

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    A comparative study on essential oils extracted from Mentha suaveolens Ehrh. from Italy is reported. Two extraction procedures were investigated: hydrodistillation and steam distillation, carried out as a continuous and fractionated procedure. Fresh and dried plant material from two harvests was used. The hydrodistillation method yielded a higher amount of essential oil. The dried plant was significantly richer in essential oil per kg of starting plant material. Gas chromatography-mass spectrometry analysis of 112 samples showed that the essential oils belong to the piperitenone oxide-rich chemotype. In addition, piperitenone, p-cymen-8-ol, and limonene were among the most abundant compounds in the different samples. A higher amount of piperitenone oxide was obtained by hydrodistillation, while steam distillation gave a higher percentage of piperitenone and limonene. The essential oils were characterized for their anti-Candida albicans activity; higher potency was observed for the samples rich in piperitenone oxide, with MIC values ranging from 0.39 to 0.78 mg·mL−1 (0.039% and 0.078% p/v). The results of this work provide a deep insight into the methodology of essential oil extraction and the associated chemical variability of M. suaveolens Ehrh. Some of the essential oils are potent against C. albicans and could be considered for potential use in therapy

    Quality of life 1 year after hospital discharge in unvaccinated pregnant women with COVID-19 respiratory symptoms: a prospective observational study (ODISSEA-PINK study)

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    IntroductionLittle is known about Quality of Life within the first court of unvaccinated COVID-19 pregnant women exposed to the pandemic stressor. Primary aim of this study was to evaluate 1 year after hospital discharge HRQoL in a cohort of COVID-19 unvaccinated pregnant patients with COVID-19.Methodsin this prospective observational study, all COVID-19 positive pregnant women at any gestational age, admitted to the Obstetric Department at the University Hospital of Udine, Italy, from 1 March 2020 to 1 March 2021, requiring or not oxygen supplementation due to SARS-CoV2 pneumonia were evaluated. Patients with a history of neurological or psychiatric disease, those with a previous abortion, and those who refused to provide written informed consent were excluded from the study. We investigated pregnant positive COVID-19 women Health-related quality of life (HRQoL) with the Short-Form Health Survey-36 (SF-36) and Post-traumatic Stress-Disorder (PTSD) with the Impact of Event Scale-Revised (IES-R).Results62 pregnant women respected the inclusion criteria of the study, and data from 33 patients were analyzed. The mean age was 32 ± 6 years, with a median gestational age of 38 weeks [IQR 34–40]. 15.2% of patients required oxygen therapy through noninvasive respiratory support (with high flow nasal cannula) for a median of 9 days [IQR 6–12]. The median Physical Component Summary (PCS) and Mental Component Summary (MCS) scores were 50.2 [IQR 46.7–53.7] and 56.0 [IQR 46.8–60.6] respectively. Ten patients out of 33 (30%) tested positive for PTSD. Maternal age, gestational age, and history of cardiac-pulmonary-kidney disease significantly affected HRQoL at multivariable analysis.DiscussionIn COVID-19 pregnant unvaccinated women some physical impairments reducing HRQoL are still present 1 year after hospital discharge. Previous medical history such as history of cardiac-pulmonary-kidney disease significantly affected HRQoL. Long and repeated follow-up should be pursued in this category of patients.Clinical trial registration:ClinicalTrials.gov, Identifier NCT04860687

    A PM10 chemically characterised nation-wide dataset for Italy. Geographical influence on urban air pollution and source apportionment

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    : Urban textures of the Italian cities are peculiarly shaped by the local geography generating similarities among cities placed in different regions but comparable topographical districts. This suggested the following scientific question: can such different topographies generate significant differences on the PM10 chemical composition at Italian urban sites that share similar geography despite being in different regions? To investigate whether such communalities can be found and are applicable at Country-scale, we propose here a novel methodological approach. A dataset comprising season-averages of PM10 mass concentration and chemical composition data was built, covering the decade 2005-2016 and referring to urban sites only (21 cities). Statistical analyses, estimation of missing data, identification of latent clusters and source apportionment modelling by Positive Matrix Factorization (PMF) were performed on this unique dataset. The first original result is the demonstration that a dataset with atypical time resolution can be successfully exploited as an input matrix for PMF obtaining Country-scale representative chemical profiles, whose physical consistency has been assessed by different tests of modelling performance. Secondly, this dataset can be considered a reference repository of season averages of chemical species over the Italian territory and the chemical profiles obtained by PMF for urban Italian agglomerations could contribute to emission repositories. These findings indicate that our approach is powerful, and it could be further employed with datasets typically available in the air pollution monitoring networks
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