Search results for "Fig"
showing 10 items of 1359 documents
Ab Initio Methods for Excited States
2005
This chapter focuses mainly on the performance of ab initio methods for the description of spectroscopic molecular properties of compounds. Most of the quantum-chemical methods developed up to date are based on the concept of the one-electron wave function. The electronic states of a system with N electrons are described by a double expansion. Molecular orbitals (MOs) are one-electron wave functions expressed as linear combinations of a known one-electron basis set (K) and the N electron wave function is formulated in a many-electron basis set formed by determinants (or linear combination of them to form spin-adapted wave functions), built as normalized antisymmetric products of MOs. Accord…
A comparison among different kinds of stator lamination in tubular linear machines
2016
In this paper the authors perform a comparison among three different stator structures for a Tubular Permanent Magnet Linear Machine. Each structure is characterized by its own lamination which is expected to contribute to the overall performance of the machine. A detailed analysis of the main figures of merit of the three configurations has been carried out in order to identify the configuration with the best characteristics. Significant data such as flux distribution, rated voltage and current, force on the moved and power losses have been compared. The results show that the choice of a mixed stator lamination allows to improve the performance of these machines.
Embodiment e percezione dello spazio alle origini della cultura indoeuropea
2018
La costruzione dell’identità scaturisce dall’esperienza corporea e dalla sua concreta rappresentazione nello spazio. Lo studio degli universali del linguaggio in relazione ai sistemi di coordinate spaziali utilizzati nelle lingue del mondo ha recentemente attirato l'attenzione della ricerca nell’ambito non solo linguistico, ma anche delle neuroscienze (Diessel 2013: 687; Kemmerer 2010). In particolare, la letteratura esistente sulla tipologia delle espressioni spaziali è tradizionalmente basata sull’assunto che il sistema di riferimento deittico o egocentrico in uso nelle lingue europee moderne costituisca un universale linguistico e culturale. Anche la tradizione filosofica, da Kant (1768)…
Enantioselective synthesis and absolute configurations of aculeatins A, B, D, and 6-epi-aculeatin D
2006
The three naturally occurring, bioactive spiroacetals aculeatins A, B, and D, as well as the non-natural 6-epi-aculeatin D have been synthesized for the first time in enantiopure form using an asymmetric allylation as the only chirality source. A further key step was a stereoselective aldol reaction with remote induction. The absolute configurations of the natural products have been established and an erroneous structural assignment has been corrected.
La transición española : ¿qué sabe el alumnado de 1º de bachillerato?
2020
El presente artículo es el resultado del análisis de una encuesta realizada a 79 estudiantes de 1º de Bachillerato sobre la transición española. Mediante esta investigación se quiere acreditar, con metodología cuantitativa, los conocimientos e ideas que el alumnado encuestado tiene acerca de ese periodo histórico tras la realización de la Educación Secundaria. Para ello se ha realizado una encuesta con variedad de preguntas entre las cuales se han incluido algunas relacionadas entre sí para comprobar posibles contradicciones en las respuestas. La encuesta abarca diferentes cuestiones: desde personajes históricos hasta actores más globales como diferentes organizaciones o movilizaciones soci…
Reconfiguration strategies to reduce mismatch effects on PV array: An Arduino-based prototype
2014
Today, solar energy represents a widespread source of electricity among all the renewable energies. One of the major problems concerning the photovoltaic (PV) arrays is the partial shading, that is the non-uniform irradiance on its parts. The partial shading leads to several undesired effects, such as mismatch between modules and a reduction of the production of electric energy. In order to alleviate the partial shading effects, different methods can be employed. Among them, the reconfiguration of the electrical connections between modules represents an alternative solution. In this paper, an algorithm of reconfiguration for a small-scale PV plant is proposed and experimental results showin…
A set of indices to assess the real performance of daylight-linked control systems
2017
Abstract The installation of Building Automation Control Systems (BACs) in general is an effective action to achieve relevant energy savings. Commercial BACs, installed in residential or small offices, often include functions of lighting control, acting as Daylight-Linked Control Systems (DLCSs). Nevertheless, because system performance is strictly dependent on different parameters, BAC’s hardware and software configuration and as well as an inaccurate commissioning do not always allow a perfect execution of the desired tasks; therefore, the system could not work as expected. Moreover, it is well known that energy saving potential is specifically related to the variability of the light envi…
Quality Assurance and Support Measures for Solar Cooling on System Level
2016
Abstract Within the IEA SHC Task 48 “Quality assurance and support measures for Solar Cooling” the analysis and evaluation of the systems has been one of the four main focuses. Here the activities are including the lab- and field-based characterization of the systems, the definition and application of performance figures, a guideline for a reliable monitoring procedure including methods for automated error detection and an updated overview on worldwide installed DEC systems including hints and good practice examples. They are furthermore leading to three different easy-to-use tools for solar cooling systems: The LCA tool considers environmental and energetic values for the evaluation, the P…
Minimum Losses Reconfiguration of MV Distribution Networks through Local Control of Tie Switches
2002
This paper deals with the problem of optimal reconfiguration of radial distribution networks for minimum loss operation. The proposed control strategy of the open-closed status of the tie-switches is distributed, since every MV/LV node is provided with local controllers having some measured entities as input. It also does not prevent the system from the future implementation of centralized control; instead it may represent the first step toward a complete automation of the distribution system. The proposed strategy is indeed organized in hierarchic levels, the highest of which may be in the future a central control. After introducing the general problem of networks reconfiguration, a review…
Economic evaluation on the use of reconfiguration systems for increase of energy production in PV plants
2016
This paper presents an economic analysis of the effectiveness of Dynamic Reconfiguration Systems (DRS) for PV plants in dependence of the incentive policies offered by several countries of the European Community. This evaluation has been achieved by means of the NPV (Net Present Value) and through the comparison between Bulgaria, Romania, Greece and Croatia. From the obtained results, it can be stated that the adoption of reconfiguration systems, in certain cases, can be a convenient solution.