Search results for "solar"

A Precise Photometric Ratio via Laser Excitation of the Sodium Layer II: Two-photon Excitation Using Lasers Detuned from 589.16 nm and 819.71 nm Reso…

2020

This article is the second in a pair of articles on the topic of the generation of a two-color artificial star (which we term a "laser photometric ratio star," or LPRS) of de-excitation light from neutral sodium atoms in the mesosphere, for use in precision telescopic measurements in astronomy and atmospheric physics, and more specifically for the calibration of measurements of dark energy using type Ia supernovae. The two techniques respectively described in both this and the previous article would each generate an LPRS with a precisely 1:1 ratio of yellow (589/590 nm) photons to near-infrared (819/820 nm) photons produced in the mesosphere. Both techniques would provide novel mechanisms f…

A theoretical investigation on the Cd doping of Cu-depleted CuInSe<inf>2</inf> materials

2011

Because of their outstanding characteristics and affordable price, polycrystalline thin film solar cells based on CuIn 1−x Ga x Se 2 (CIGS) absorber layer have emerged to be one of the most promising materials for photovoltaic applications [1–2]. To further enhance the efficiency of these solar cells much effort is spent on the in-depth investigation of the production methods. However, the effect of structural defects and dopants upon the macroscopic properties and morphology of epitaxially grown CIGS films is not yet fully understood [3]. More importantly, it is well established that the best cells can be prepared by growing the CIGS absorber layer under Cu-poor conditions [4]. Thus, it is…

Automorphism Groups of Certain Rational Hypersurfaces in Complex Four-Space

2014

The Russell cubic is a smooth contractible affine complex threefold which is not isomorphic to affine three-space. In previous articles, we discussed the structure of the automorphism group of this variety. Here we review some consequences of this structure and generalize some results to other hypersurfaces which arise as deformations of Koras–Russell threefolds.

Building integrated solar thermal design: assessment of performances of a low cost solar wall in a typical Italian building

2016

Abstract Present work deals with the topic of building integration of solar thermal collector (BIST) as a refurbishment measure. Such equipment, more than its main function as heating generator, plays a specific role as a building component (envelope finishes, thermal insulation layer, roof cover etc). Consequently, from a heat transfer point of view, an integrated component affects twice the global building balance: supporting the thermal plant (i.e. providing heat for final uses) and modifying the wall heat-transfer pattern (i.e. reducing thermal losses). In turn, the collector performance itself is influenced by the wall structure (back losses reduction). Present work proposes a method f…

BUILDING INTEGRATED SOLAR THERMAL DESIGN: CHARACTERISATION AND ASSESSMENT OF PERFORMANCES OF A LOW COST SOLAR WALL.

Solar PAR and UVR modify the community composition and photosynthetic activity of sea ice algae

2015

The effects of increased photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) on species diversity, biomass and photosynthetic activity were studied in fast ice algal communities. The experimental set-up consisted of nine 1.44 m(2) squares with three treatments: untreated with natural snow cover (UNT), snow-free (PAR + UVR) and snow-free ice covered with a UV screen (PAR). The total algal biomass, dominated by diatoms and dinoflagellates, increased in all treatments during the experiment. However, the smaller biomass growth in the top 10-cm layer of the PAR + UVR treatment compared with the PAR treatment indicated the negative effect of UVR. Scrippsiella complex (mainly…

La asimilación de Barba Azul con la figura del tirano en las obras de Perrault y Bartók

2011

De acuerdo con Paul Ricoeur, se puede acceder a toda relación simbólica desde tres diferentes niveles de comprensión; a saber, uno cósmico, uno onírico y uno poético. El estudio de cada uno de ellos aportará una serie de directrices que, puestas en común con las restantes, permitirán la observación de rasgos análogos y sintomáticos en el texto trabajado, lo que posibilitará comprender, más allá de cuanto en la narración resulta explícito, aquello que permanece en la oscuridad del proceso formativo. Aplicaremos estas propuestas sobre el Barba Azul de Perrault para confrontarlas con la obra homónima de Bartók y desvelar, de este modo, las sorprendentes asimilaciones encontradas entre el señor…

Solar Inexhaustible Power Source for Wireless Sensor Node

2008

Currently the appearance of really low power wireless transceivers is motivating the use of renewable energies to power embedded wireless sensor nodes in many applications. Nevertheless, energy storage and its degradation still keep on being the main issues in the design of any battery powered device. We present an autonomous power source based on a new system architecture, which uses the energy scavenging to replenish two different rechargeable energy buffers instead of the conventional single one. Combining appropriately a degradable large backup battery (Lithium-Ion) and a shorter but non degradable storage element (Supercapacitor), the lifetime of the group can be widely extended to wha…

Performance Assessment of Building Integrated Photovoltaic and Battery Energy System: A Case Study of TERI-Retreat Facilty in India

2019

Building integrated photovoltaic (BIPV) with energy storage can play an important role not only in demand side management but also in a micro-grid system in coordination with other distributed generators. The operational analysis of BIPV system and energy storage with contribution to local load profile is needed for its grid connected operation, as well as for integrating it in the micro-grid system. In this work, a typical institution has been selected, where the PV system and energy storage are operated for supplying local load in coordination with the grid. The institutional load profile has been analyzed with essential and non-essential loads for understanding the operation and contribu…

Long-term optical variability of high-mass X-ray binaries. II. Spectroscopy

2016

We present the results of our monitoring program to study the long-term variability of the Halpha line in high-mass X-ray binaries. We have carried out the most complete optical spectroscopic study of the global properties of high-mass X-ray binaries so far with the analysis of more than 1100 spectra of 20 sources. Our aim is to characterise the optical variability timescales and study the interaction between the neutron star and the accreting material. Our results can be summarised as follows: i) we find that Be/X-ray binaries with narrow orbits are more variable than systems with long orbital periods, ii) we show that a Keplerian distribution of the gas particles provides a good descripti…