Search results for "Generation"

Effects of Weak Links in the Nonlinear Microwave Response of MgB2 Superconductor

2006

We report experimental results of second-harmonic (SH) response at microwave frequency in several ceramic MgB2 samples, prepared by different methods. The SH signal has been investigated as a function of the temperature and DC magnetic field. The investigation has been carried out at low magnetic fields, where nonlinear processes arising from motion of Abrikosov fluxons are ineffective. We show that the low-temperature SH emission is ascribable to processes involving weak links. Comparison among the peculiarities of the SH signal radiated by the different samples shows that the presence of weak links strongly depends on the sample preparation method, as well as the purity and morphology of …

Second-harmonic generation in surface periodically poled lithium niobate waveguides:On the role of multiphoton absorption

2008

Second harmonic generation is investigated in lithium niobate channels realized by proton exchange and quasi-phase-matched by surface periodic-poling. The reduction in conversion efficiency at high powers is interpreted in terms of multi-photon absorption via two-color terms, yielding an estimate of the dominating three-photon process.

Frequency doubling in surface periodically poled lithium niobate waveguides: Competing effects

2007

We fabricated α-phase pro ton-exchanged (PE) lithium niobate (LN) channel waveguides quasi phase-matched (QPM) via surface periodic poling (SPP) and carried out the first experimental demonstration of second harmonic generation (SHG) in such devices.[1] Experiments were performed by employing an optical parametric amplifier/oscillator producing 25 ps pulses in the range 1.1-1.6 μm with a line-width less than 2cm−1 and a repetition rate of 10Hz. SHG measurements were performed either at a fixed wavelength by varying the fundamental frequency (FF) input power or by scanning the FF wavelength, ratioing the second harmonic (SH) output to the FF input to obtain the conversion efficiency. By repe…

Boolean operations with implicit and parametric representation of primitives using R-functions

2005

We present a new and efficient algorithm to accurately polygonize an implicit surface generated by multiple Boolean operations with globally deformed primitives. Our algorithm is special in the sense that it can be applied to objects with both an implicit and a parametric representation, such as superquadrics, supershapes, and Dupin cyclides. The input is a constructive solid geometry tree (CSG tree) that contains the Boolean operations, the parameters of the primitives, and the global deformations. At each node of the CSG tree, the implicit formulations of the subtrees are used to quickly determine the parts to be transmitted to the parent node, while the primitives' parametric definition …

A modified surgical approach for hard and soft tissue reconstruction of severe periimplantitis defects – Laser‐assisted periimplant defect regenerati…

2019

Cerebral expression of neuroglobin and cytoglobin after deep hypothermic circulatory arrest in neonatal piglets

2010

Deep hypothermic circulatory arrest (DHCA) is used in corrective cardiac surgery for complex congenital heart disease. Endogenous protective mechanisms may be responsible for the prevention of brain damage after hypothermic ischemia. Neuroglobin and cytoglobin are expressed in brain cells and appear to modulate hypoxic-ischemic brain injury. However, their neuroprotective potency is still not understood. Thus the aim of this study was to detect the influence exerted by DHCA on their expression.The effects of DHCA were analyzed in a neonatal piglet model with cardiopulmonary bypass, DHCA of 60 and 120 min and subsequent reperfusion of 6h. Complete histological analysis and changes in the mRN…

New frontiers in sustainable energy production and storage

2015

Evidently, one of the most effective ways to reduce CO2 emissions consists in the deployment of renewable energies, with the advantage of securing and expanding the energy supplies of a given country. The main problem that arises is due to the intermittent temporary character of many renewable resources like solar and wind. For this reason, it has been recently concluded that in case of high integration of renewables into the distribution grid (more than about 30% of the electricity mix), the implementation of energy storage systems together with smart grids is necessary. Therefore, renewable energies for large scale power production in country would usually require the availability of a su…

Feed-in Tariffs for Grid-connected PV Systems: The Situation in the European Community

2007

Distributed generation demonstrates to be able to significantly influence the electric power system bringing considerable benefits to the quality of service and improving the energetic efficiency of the distribution network. In particular, in the last few years, distributed generation from renewable sources is considerably increased thanks to the many support policies promoted worldwide with the aim of facing the environmental issue and the problem of the permanent rise of prices of the fossil energy. In this contest the paper presents a study of the "feed-in tariffs" financing measure carried out, at present, in many European countries and responsible of the increase in these last years of…

How social, environmental, and economic CSR affects consumer-perceived value: Does perceived consumer effectiveness make a difference?

2018

This study analyzes the influence of consumer‐perceived dimensions of corporate social responsibility (CSR) from a sustainable development approach (i.e. economic, social, and environmental) on the dimensions of perceived value (i.e. utilitarian, emotional, and social value). The study also analyzes the moderating effect of perceived consumer effectiveness (PCE) in the value generation process around CSR. A theoretical model is estimated with data from 661 consumers of Inditex or Danone products, leading firms in the textile and dairy sectors, respectively. Results indicate that functional value is determined by economic and social dimensions of CSR. Emotional value can be enhanced through …

Sustainable and cost-efficient energy supply and utilisation through innovative concepts and technologies at regional, urban and single-user scales

2019

Abstract The environmental impact of the energy sector and the security and economics of energy supply and utilisation have been raising increasing concerns, stimulating the search for innovative solutions for a sustainable use of resources. This article provides an overview of published research in this area, with a focus on papers contributed in special issues of leading journals dedicated to the series of Conferences on Sustainable Development of Energy, Water and Environment Systems (SDEWES), including the articles in the current special issue. Based on this review, research trends are identified and achievements supporting the energy transition are highlighted. The studies that focused…