Search results for " EFFICIENCY"
showing 10 items of 1091 documents
Evaluation of Load transfer in rigid pavements by Rolling wheel deflectometer and Falling weight deflectometer
2020
Abstract Rigid pavements have widespread use, e.g, in motorways and airports, due to their excellent properties such as high bearing capacity and long lifetime. However, when rigid pavements fail it is often due to bad load transfer efficiency (LTE) at its joints. Traditional methods of measuring LTE can be time consuming. Here, we study the possibility of measuring LTE using a moving load with the aim of achieving higher productivity. An experiment simulating Rolling Weight Deflectometer (RWD) measurements on a joint was carried out to gain understanding and confidence that can guide the analysis of real RWD data. Continuous data from measurements across a joint allows for determination of…
A wireless battery charger architecture for consumer electronics
2012
In this paper, an innovative design of a wireless battery charger for portable electronic devices is proposed. The wireless power transfer is implemented through the magnetic coupling between a power transmitter, which is connected to the grid, and a power receiver, which is integrated inside the load device. An innovative receiver architecture which heavily improves the power conversion efficiency is presented. The proposed solution is standard compliant and suitable for IC implementation. A comparison between a conventional and the proposed receiver architectures is carried out by SPICE simulations. As shown by simulation results, a power efficiency increase by 40% is provided by the prop…
1 Hop or 2 hops: Topology analysis in Body Area Network
2014
Wireless Body Area Networks (WBANs) have recently received much attention due to the possibility to be used in healthcare applications. For these applications, link reliability and energy efficiency are critical issues, as in many cases, information carried can be vital for the patient and batteries cannot be easily replaced. The wireless on-body channel experiences significant temporal variation due to body movements and the use of relays is sometimes necessary in order to guarantee reliability or improve lifetime. In this paper, an experimental evaluation is used to give a better understanding about reliability, energy consumption and lifetime in a single hop or a two hops communication. …
Artificial dielectric optical structures: A challenge for nanofabrication
1998
Diffractive optical components can be made using multiple level kinoforms or single level artificial dielectric structures. The latter require the fabrication of pillars of equal depth but differing width and spacing. As a demonstration device, the diffractive optic equivalent of a wedge has been made in GaAs for use at 1.15 μm. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. © 1998 American Vacuum Society.
The use of energy in the Mediterranean fishing catching sector. A Sicilian perspective
2010
This article address an issue of paramount importance in the Mediterranean area, that is the efficient use of energy and sustainability of fishing sector. A recent study concerning the situation of Fishery and Aquaculture in Sicily highlighted that the Sicilian fishing system requires a bigger amount of energy than the typical Italian or European situation, in order of getting the product available to the market. On the other hand this involves an higher level of environmental pollution, for a given quantity of catch. One of the main findings is that there is a need for a clear, scientifically-founded panorama of the situation and that further studies should be undertaken to provide fishing…
Sistema di irrigazione a perno centrale
2021
L’invenzione consiste nell’impiego, nell’irrigazione pivot, dei comuni irrigatori rotanti che si utilizzano nei sistemi di irrigazione a pioggia (o per aspersione), che hanno il vantaggio, rispetto agli spruzzatori ed ai gocciolatori, di essere dotati di un ugello terminale di elevato diametro (4-30 mm). L’idea nasce quindi dalla ricerca di un sistema irriguo che conservi i benefici dell’irrigazione pivot (completa automatizzazione, manodopera limitata alla manutenzione degli apparecchi erogatori, elevata efficienza) e che al contempo rimuova del tutto il problema dell’occlusione degli apparecchi erogatori. Vengono così azzerati i costi di manodopera e, soprattutto, viene consentito l’impie…
Performance of dye-sensitized solar cells based on novel sensitizers bearing asymmetric double D−π−A chains with arylamines as donors
2012
Abstract Three novel, metal-free organic sensitizers bearing two asymmetric double donor-π-acceptor (D-π-A) chains ( DC1 - 3 ), each, and a reference dye containing single D-π-A chain ( SC ) with cyanoacrylic acid as electron acceptor are synthesized. Their photophysical, electrochemical properties and the performances of the corresponding dye-sensitized solar cells (DSSCs) are further investigated. The dyes, DC1, DC2 and DC3 contain one chain with diphenylamine and another chain with carbazole or phenothiazine as electron donor, while diphenylamine is only employed as electron donor in SC . Compared to the inferior solar energy to electricity conversion efficiency ( η ) of 2.82%, 4.66% and…
The Role of Emission Layer Morphology on the Enhanced Performance of Light-Emitting Diodes Based on Quantum Dot-Semiconducting Polymer Hybrids
2016
The influence of the morphology of quantum dot (QD)-semiconducting polymer hybrid emission layers on the performance of quantum dot-based light emitting diodes (QLEDs) is systematically investigated. Chemically grafted QD-semiconducting polymer hybrids are fabricated by the ligand exchange procedure between CdSe/CdxZn1−xS QDs and a new block copolymer consisting of a carbazole-based electroactive block with a low highest occupied molecular orbital level and a disulfide-based anchor block. The performance of QLEDs with hybrid emission layers is compared with QLEDs utilizing QD-only and physically mixed QD/polymer emission layers. It is shown that only in the emission layers formed by chemica…
Thermal, glass-forming, nonlinear optical and holographic properties of "push-pull" type azochromophores with triphenyl moieties containing isophoren…
2013
Molecular organic compounds with electron donating fragment bounded through π-conjugated system with electron acceptor fragment, as well as with incorporated triphenyl groups in their molecules show potential for creating cheap and simple solution processable materials with nonlinear optical properties. Additional insertion of azobenzene fragment in their structures makes them also possible to form holographic volume and surface relief gratings (SRG) after exposure to laser radiation, which could be useful for holographic data storage. For these purposes polymers are generally used. However, their application is complicated and challenging task as in every attempt to obtain the same polymer…
Perovskite solar cells prepared by flash evaporation
2015
A simple vacuum deposition method for the preparation of high quality hybrid organic-inorganic methylammonium lead iodide perovskite thin films is reported. When sandwiched in between organic charge transporting layers, such films lead to solar cells with a power conversion efficiency of 12.2%.