779 research outputs found

    ReLambro. Il fiume nuova infrastruttura ecologica della metropoli milanese

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    Lo studio raccoglie gli esiti di tre anni di progetto per la rete ecologica del Lambro Milanese cofinanziato da Fondazione Cariplo, con partner Politecnico di Milano, Ersaf (capofila), Legambiente Lombardia, PLIS Media Valle Lambro. Sviluppato in forma multidisciplinare come un documento di ricerca e azione, si propone con un vero e proprio documento di riferimento per tutti i soggetti che vogliono operare sul Lambro, o più in generale in ambiti fluviali in contesti urbani, fornendo uno strumento pratico da utilizzare per le azioni di riqualificazione fluviale e ambientale, nell’ottica di migliorare la funzionalità eco-sistemica del territorio e costruire e rafforzare la connessione ecologica a tutela della biodiversità

    Spatial and temporal variability of the dimethylsulfide to chlorophyll ratio in the surface ocean: an assessment based on phytoplankton group dominance determined from space

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    Dimethylsulfoniopropionate (DMSP) is produced in surface seawater by phytoplankton. Phytoplankton culture experiments have shown that nanoeucaryotes (NANO) display much higher mean DMSP-to-Carbon or DMSP-to-Chlorophyll (Chl) ratios than Prochlorococcus (PRO), Synechococcus (SYN) or diatoms (DIAT). Moreover, the DMSP-lyase activity of algae which cleaves DMSP into dimethylsulfide (DMS) is even more group specific than DMSP itself. Ship-based observations have shown at limited spatial scales, that sea surface DMS-to-Chl ratios (DMS:Chl) are dependent on the composition of phytoplankton groups. Here we use satellite remote sensing of Chl (from SeaWiFS) and of Phytoplankton Group Dominance (PGD from PHYSAT) with ship-based sea surface DMS concentrations (8 cruises in total) to assess this dependence on an unprecedented spatial scale. PHYSAT provides PGD (either NANO, PRO, SYN, DIAT, Phaeocystis (PHAEO) or coccolithophores (COC)) in each satellite pixel (1/4° horizontal resolution). While there are identification errors in the PHYSAT method, it is important to note that these errors are lowest for NANO PGD which we typify by high DMSP:Chl. In summer, in the Indian sector of the Southern Ocean, we find that mean DMS:Chl associated with NANO + PHAEO and PRO + SYN + DIAT are 13.6±8.4 mmol g−1 (n=34) and 7.3±4.8 mmol g−1 (n=24), respectively. That is a statistically significant difference (P<0.001) that is consistent with NANO and PHAEO being relatively high DMSP producers. However, in the western North Atlantic between 40° N and 60° N, we find no significant difference between the same PGD. This is most likely because coccolithophores account for the non-dominant part of the summer phytoplankton assemblages. Meridional distributions at 22° W in the Atlantic, and 95° W and 110° W in the Pacific, both show a marked drop in DMS:Chl near the equator, down to few mmol g−1, yet the basins exhibit different PGD (NANO in the Atlantic, PRO and SYN in the Pacific). In tropical and subtropical Atlantic and Pacific waters away from the equatorial and coastal upwelling, mean DMS:Chl associated with high and low DMSP producers are statistically significantly different, but the difference is opposite of that expected from culture experiments. Hence, in a majority of cases PGD is not of primary importance in controlling DMS:Chl variations. We therefore conclude that water-leaving radiance spectra obtained simultaneously from ocean color sensor measurements of Chl concentrations and dominant phytoplankton groups can not be used to predict global fields of DMS

    The calculation of the cardiac troponin T 99th percentile of the reference population is affected by age, gender, and population selection: A multicenter study in Italy.

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    Background: The aim of this study is to determine the 99th upper-reference limit (URL) for cardiac troponin T (cTnT) in Italian apparently healthy subjects. Methods: The reference population was selected from 5 cities: Bolzano (n = 290), Milano (CAMELIA-Study, n = 287), Montignoso (MEHLP-Study, n = 306), Pisa (n = 182), and Reggio Calabria (MAREA-Study, n = 535). Subjects having cardiac/systemic acute/chronic diseases were excluded. Participants to MEHLP project underwent cardiac imaging investigation. High-sensitive cTnT was measured with Cobas-e411 (Roche Diagnostics). Results: We enrolled 1600 healthy subjects [54.6%males; age range 10–90 years; mean (SD): 36.4 (21.2) years], including 34.6% aged b20 years, 54.5% between 20 and 64 years, and 10.9% over 65 years. In the youngest the 99th URL was 10.9 ng/L in males and 6.8 ng/L in females; in adults 23.2 ng/L and 10.2 ng/L; and in elderly 36.8 ng/L and 28.6 ng/L. After the exclusion of outliers the 99th URL values were significantly decreased (P b 0.05) in particular those of the oldest (13.8 ng/L and 14 ng/L). MEHLP participants were divided in healthy and asymptomatic, according to known cardiovascular risk factors (HDL, LDL, glucose, C-reactive protein): the 99th URL of cTnT values of these subgroups was significantly different (19.5 vs. 22.7, P b 0.05). Conclusions: 99th URL of cTnT valueswas strongly affected by age, gender, selection of subjects and the statistical evaluation of outliers

    Innovative 3-D Printing Processing Techniques for Flexible and Wearable Planar Rectennas

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    This work demonstrates the use of a low-cost, lossy, flexible substrate processed by novel 3-D printing techniques which significantly mitigate its intrinsic losses, thus providing performance comparable to those of traditional substrates. These processing techniques are applied to both microstrip and coplanar waveguide structures; they are first derived theoretically, starting from the electromagnetic theory of modes propagation, then numerically validated by full-wave analysis, and finally experimentally verified. The design of a miniaturized 868 MHz rectenna, adopting a coplanar-fed patch antenna based on the proposed fabrication approach, is presented. By means of nonlinear/electromagnetic co-design, the antenna is directly matched to the rectifier. A 30-dB power range starting from -20 dBm is considered. Direct matching allows to get rid of a dedicated matching network and its associated losses, resulting in a slight efficiency increase and a significant reduction of the overall dimensions. Finally, the 3-Dprinted prototype is presented: the overall rectenna performance proves that design freedom enabled by 3-D printing paves the way to the use of low-cost flexible dielectric materials, even with poor electromagnetic properties, to realize wearable battery-free wireless nodes

    A Novel 3-D Printed Dual-Port Rectenna for Simultaneous Energy Harvesting and Backscattering of a Passively Generated UWB Pulse

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    This work presents the design and characterization of a new compact rectenna system, fully three-dimensional (3-D) printed on a low-cost material, the polylactic acid (PLA). The rectenna consists of a patch-like antenna, with two orthogonal excitation ports, suitably designed to achieve both ultra-high-frequency (UHF) and ultra-wideband (UWB) cross-polarized radiation performance. The first port harvests multi-tone RF power at UHF, around 2.47 GHz (for the present case 8 equally spaced non-synchronized tones are used); the second port backscatters the intermodulation (IM) products generated by the rectifier, realizing a quasi-UWB pulse. The rectifier consists of a single-diode embedded into two linear subnetworks: one, connecting the UHF port and the diode, is co-designed to ensure dc-block and rectifier-antenna matching in the UHF band; the second one combines a high-pass filter, connecting the diode and the UWB port, to backscatter the passive pulse, and a dc path to collect the converted dc power. The 3-D etching of the low-cost substrate is optimized to obtain antenna performance comparable to those achieved with specialized RF materials. The system design is carried out by integrating full-wave and nonlinear simulations with the manifold goal of minimizing the overall footprint, ensuring UWB-mask-compatible radiated spectra and RF-to-dc conversion efficiency. A 3-D printed prototype has been realized and experimentally characterized. With a total received power of -15 dBm, equally distributed over eight tones spaced by 1 MHz, a quasi-UWB pulse power peak of about 80 nW has been demonstrated

    Focusing RF-on demand by logarithmic frequency-diverse arrays

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    The radiating systems exploiting the frequency diversity of the antennas are powerful architectures, that can have a big impact on wireless power transmission applications, but their characterization is merely theoretical. This paper offers a deep and critical numerical analysis of frequency- diverse arrays and shows the advantages of the family with logarithmic distribution of the frequency for radio-frequency energy focusing goals. For the first time, these systems are analyzed through a Harmonic Balance-based simulation combined with the full-wave description of the array made of eight planar monopoles: the rigorous results confirm the potentialities of these complex radiating systems, in particular show how the time-dependency of the radiating mechanism can be favorably deployed

    Methodology for integrated socio-economic assessment of offshore platforms : towards facilitation of the implementation of the marine strategy framework directive

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    In this paper a Methodology for Integrated Socio-Economic Assessment (MISEA) of the viability and sustainability of different designs of Multi-Use Offshore Platforms (MUOPs) is presented. MUOPs are designed for multi-use of ocean space for energy extraction (wind power production and wave energy), aquaculture and transport maritime services. The developed methodology allows identification, valuation and assessment of: the potential range of impacts of a number of feasible designs of MUOP investments, and the likely responses of those impacted by the investment project. This methodology provides decision-makers with a valuable decision tool to assess whether a MUOP project increases the overall social welfare and hence should be undertaken, under alternative specifications regarding its design, the discount rate and the stream of net benefits, if a Cost-Benefit Analysis (CBA) is to be followed or sensitivity analysis of selected criteria in a Multi-Criteria Decision Analysis (MCDA) framework. Such a methodology is also crucial for facilitating of the implementation of the Marine Strategy Framework Directive (MSFD adopted in June 2008) that aims to achieve good environmental status of the EU's marine waters by 2020 and to protect the resource base upon which marine-related economic and social activities depend. According to the MSFD each member state must draw up a program of cost-effective measures, while prior to any new measure an impact assessment which contains a detailed cost-benefit analysis of the proposed measures is required

    An all-in-one dual band blade antenna for ads-b and 5g communications in uav assisted wireless networks

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    This paper is aimed at the characterization and manufacturing of an SMA coaxial fed com-pact blade antenna with dual frequency characteristics for broadband applications on board of Unmanned Air Vehicles (UAVs). This antenna is linearly polarized, and it combines the benefits of Automatic Dependent Surveillance-Broadcast (ADS-B) and 5th Generation (5G) communications in one single element, covering both the 1.030–1.090 GHz and the 3.4–3.8 GHz bands thanks to a bent side and a ‘C’ shaped slot within the radiation element. Starting from the simulation outcomes on an ideal ground plane, the results are here extended to a bent ground plane and on two UAV com-mercial CAD models. Details of manufacturing of the antenna in both aluminium and FR-4 substrate materials are presented. The comparison between measurements and simulations is discussed in terms of return loss, bandwidth, gain, and radiation pattern. Results show an antenna with a low profile and a simple structure that can be employed in various wideband communication systems, suiting future UAV assisted 5G networks while being perfectly compliant with forthcoming ADS-B based Detect-And-Avoid (DAA) technologies in Unmanned Aerial Traffic Management (UTM)

    Microwave Devices for Wearable Sensors and IoT

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    The Internet of Things (IoT) paradigm is currently highly demanded in multiple scenarios and in particular plays an important role in solving medical-related challenges. RF and microwave technologies, coupled with wireless energy transfer, are interesting candidates because of their inherent contactless spectrometric capabilities and for the wireless transmission of sensing data. This article reviews some recent achievements in the field of wearable sensors, highlighting the benefits that these solutions introduce in operative contexts, such as indoor localization and microwave sensing. Wireless power transfer is an essential requirement to be fulfilled to allow these sensors to be not only wearable but also compact and lightweight while avoiding bulky batteries. Flexible materials and 3D printing polymers, as well as daily garments, are widely exploited within the presented solutions, allowing comfort and wearability without renouncing the robustness and reliability of the built-in wearable sensor
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