104,375 research outputs found
Disposizioni sulla genitorialità: congedo di paternità e vouchers
No full textDisposizioni sulla genitorialità contenute nella riforma Fornero: 1. La debolezza del disegno. – 2. Il congedo di paternità. – 3. I Voucher
UHF rectenna using a bowtie antenna
No full textAbstract—In this paper, a rectifying antenna (rectenna) for energy scavenging applications is presented. The proposed device uses a modified bowtie antenna to collect the electromagnetic energy coming from UHF RFID systems, and RF Schottky diodes to convert it into DC power. Experimental results at 866MHz demonstrating an RF-to-DC conversion efficiency of about 65 % with an input power density of 60µW/cm2 will be presented and discussed. 1
Functional capacity after traditional Chinese Medicine (Qi Gong) training in patients with chronic atrial fibrillation: a randomized pilot study.
No full text
Multi-fidelity surrogate-based optimization of transonic and supersonic axial turbine profiles
No full textAutomated Fluid-dynamic Shape Optimization plays a key role in the design of turbomachinery and typically combines Computational Fluid Dynamics (CFD) solvers, parametrization techniques and numerical optimization methods, generally categorized as either direct or surrogate-based (SBO) ones. Here, a particular focus is given to SBO exploiting surrogate models constructed from low-fidelity models, often referred to as variable or multi-fidelity optimization. This study presents a multi-fidelity SBO approach for the optimization of a supersonic turbine cascade operating with an organic fluid and of the transonic LS89 high-pressure turbine vane. A cokriging method is used to simultaneously take into account quantities of interest (QoI) coming from models of different fidelities providing a global surrogate model. A classic Bayesian global optimization method permits to iteratively select promising designs. It relies on the maximization of the so-called Expected Improvement criterion. A geometrical parametrization technique based on B-splines is considered to describe the profile geometry. The total pressure loss coefficient is minimized while the mass flow rate is constrained. For both the application cases, the optimization study reveals a speed-up of 3 to 5 times in the convergence process with respect to classic optimization frameworks based on a single fidelity, while providing similar improvements in terms of fitness functions
A new device hypothesis for water extraction from air and basic air condition system in developing countries
No full textThis work proposes a new device for air treatment with dehumidification and water recovery/storage, with possible mitigation of indoor environmental conditions. The system is based on Peltier cells coupled with a horizontal earth‐to‐air heat exchanger, it is proposed as an easy‐to-implement alternative to the heat pumps and air handling units currently used on the market, in terms of cost, ease of installation, and maintenance. The process provides the water collection from the cooling of warm‐humid air through a process that leads to condensation and water vapor separation. The airflow generated by a fan splits into two dual flows that lap the two surfaces of the Peltier cells, one flow laps the cold surfaces undergoing sensible, latent cooling with dehumidification; the other flow laps the hot surfaces and heats up. The airflow undergoes thermal pre‐treatment through the underground horizontal geothermal pipe that precedes the Peltier cells. In the water storage tank, which also works as a mixing chamber, the two air streams are mixed to regulate the outlet temperature. The system can be stand‐alone if equipped with a photovoltaic panel and a micro wind turbine, able to be used in places where electricity is absent. The system, with different configurations, is modeled in the African city Kigali, in Rwanda
Walls comparative evaluation for the thermal performance improvement of low-rise residential buildings in warm Mediterranean climate
No full textBuildings built in warm climates are affected by severe overheating problems in summer, which negatively affects people's comfort and health. For these reasons, many users are forced to install cooling systems, leading to an increase in costs, consumption and a meaning impact on the environment. This study gives a valid method to monitor the overheating problems in buildings located in Mediterranean climates, without the use of cooling systems, but just with an accurate design of the envelope. The main challenge is to demonstrate that the hourly monitoring of the internal operative temperature (TOP), in accordance with the UNI EN ISO 52016, is able of defining univocally the performances of the building, taking into consideration the characteristics of the envelope. The optimization of this parameter permits to reach high level of internal comfort in a building, ensuring the designer to identify the best choice of building materials that compose the envelope. The TOP trends, for a whole year, are tested on a single-residential building model located in a warm Mediterranean climate, considering different configurations of the external walls. The results put in evidence that the best solutions are characterized by the presence of the double layer of tuff, with a very massive layer in the internal side and resistive layer outside. At the end, this study demonstrates that once optimized the envelope, it is easier to reach good values of internal operative temperature with the only use of a mechanical ventilation system
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