Search results for "efficient"

High-pressure optical absorption in InN: Electron density dependence in the wurtzite phase and reevaluation of the indirect band gap of rocksalt InN

2012

We report on high-pressure optical absorption measurements on InN epilayers with a range of free-electron concentrations (5×1017–1.6×1019 cm−3) to investigate the effect of free carriers on the pressure coefficient of the optical band gap of wurtzite InN. With increasing carrier concentration, we observe a decrease of the absolute value of the optical band gap pressure coefficient of wurtzite InN. An analysis of our data based on the k·p model allows us to obtain a pressure coefficient of 32 meV/GPa for the fundamental band gap of intrinsic wurtzite InN. Optical absorption measurements on a 5.7-μm-thick InN epilayer at pressures above the wurtzite-to-rocksalt transition have allowed us to o…

The resistivity and thermopower of amorphous Mg-Zn alloys

1983

The resistivity and thermopower of amorphous Mg-Zn alloys have been computed as a function of temperature and composition. The diffraction model incorporating the dynamical partial structure factors is applied. The effect of the electron mean free path is investigated. The authors find that the resistivity is well described by the model, and that the inclusion of the mean free path does not change the results considerably. In the case of thermopower the diffraction model turns out to be inadequate: it gives a composition dependence which is against the experimental evidence. This suggests that there exists another scattering mechanism, which is not accounted for by the diffraction model. Th…

Temperature Dependent Quantum Efficiencies in Multicrystalline Silicon Solar Cells

2015

Abstract Several field studies comparing modules based on Elkem Solar Silicon ® (ESS ® ) cells with reference modules based on non-compensated virgin polysilicon show that the compensated ESS ® modules outperform the reference modules with comparable installed capacity under certain operating conditions. At high temperatures and high irradiation conditions the modules based on compensated silicon produce more energy than the reference modules. In order to increase the understanding of the observed effect cells are studied at different temperatures by the means of IV-characteristics as well as quantum efficiencies. Quantum efficiency measurements show that the main difference between ESS ® c…

Lp-uniqueness for elliptic operators with unbounded coefficients in RN

AbstractLet A be an elliptic operator with unbounded and sufficiently smooth coefficients and let μ be a (sub)-invariant measure of the operator A. In this paper we give sufficient conditions guaranteeing that the closure of the operator (A,Cc∞(RN)) generates a sub-Markovian strongly continuous semigroup of contractions in Lp(RN,μ). Applications are given in the case when A is a generalized Schrödinger operator.

Sviluppo di un convertitore di energia solare (S.E.C. - Solar Energy Converter) per applicazioni di efficientamento energetico in agricoltura attrave…

2014

Implementation of walk-through audits for designing energy management system: A first step towards an efficient campus

2020

Abstract The purpose of this study is to design a concept of energy management control system (EMCS) at the UNSADA campus, Jakarta, Indonesia by utilizing the results of the previous walkthrough audit. EMCS is an important first step by involving all parties on campus to be concerned the sustainable energy savings. The energy efficiency program utilizes the campus as an energy laboratory to identify, recommend, implement and evaluate the energy consumption, so that the expected energy efficiency targeted by the top managements can be achieved. This program is motivated by several reasons, such as; to support government policies in reducing dependence on fossil energy by implementing energy …

Optimization on ports activation towards energy efficient data center networks

2018

Nowadays, Internet of thing including network support (i.e. checking social media, sending emails, video conferencing) requires smart and efficient data centers to support these services. Hence, data centers become more important and must be able to respond to ever changing service requirements and application demands. However, data centers are classified as one of the largest consumers of energy in the world. Existing topologies such as ScalNet improves the data center scalability while leading to enormous amounts of energy consumption. In this paper, we present a new energy efficient algorithm for ScalNet called Green ScalNet. The proposed topology strikes a compromise between maximizing …

ERCP : Energy-Efficient and Reliable-Aware Clustering Protocol for Wireless Sensor Networks

2022

Wireless Sensor Networks (WSNs) have been around for over a decade and have been used in many important applications. Energy and reliability are two of the major problems with these kinds of applications. Reliable data delivery is an important issue in WSNs because it is a key part of how well data are sent. At the same time, energy consumption in battery-based sensors is another challenge. Therefore, efficient clustering and routing are techniques that can be used to save sensors energy and guarantee reliable message delivery. With this in mind, this paper develops an energy-efficient and reliable clustering protocol (ERCP) for WSNs. First, an efficient clustering technique is proposed for…

GLOBAL SAVING EVALUATION THROUGH A RETROFITTING ACTION

2014

The paper shows a work that was carried out by the authors as members of the PADesign Company, academic spin off of University of Palermo. Currently, energy retrofit of existing building has become an important goal, because it is now widely recognized that the buildings are one of the main causes of CO2 production and of non-renewable energy consumptions. To act on the energy performance of existing buildings (adapting their performances to those required by regulations) is an important strategy to reduce energy consumptions since they are much more than new buildings. Through the application of innovative technologies and methodologies and the choice of appropriate investments, the retrof…

A computational approach to evaluate temperature and heat partition in machining with multilayer coated tools

2003

Abstract In this paper, analytical models for estimating the interface temperature and heat partition to the chip in continuous dry machining of steels with flat-faced tools treated with multilayer coatings are presented. The database for modeling includes changes in the thermal properties of both workpiece and substrate/coating materials and the Peclet and Fourier numbers occurring at actual interface temperatures. Process outputs involve the average tool–chip interface temperature, the tool–chip contact length, the friction energy and the heat balance between the moving chip and stationary tool. It was found that the heat partition coefficient varies significantly from 0.65 to 0.8 when us…