Diffusion de l'oxygene et dynamique de spin dans les phtalocyanines radicalaires

SIGLEINIST T 77508 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Solar based large scale power plants : what is the best option

There are very few published data comparing performance and cost of thermal and photovoltaic (PV) based solar power generations. With recent intense technology and business developments there is a need to establish a comparison between these two solar energy options. We have developed a simple model to compare electricity cost using these two options without any additional fuel source of hybridization. Capital along with operation and maintenance (O&M) costs and other parameters from existing large scale solar farms are used to reflect actual project costs. To compete with traditional sources of power generation, solar technologies need to provide dispatchable electric power to respond to demand during peak hours. Different solutions for energy storage are available. In spite of their high capital cost, adding energy storage is considered a better long term solution than hybrid solar systems for large scale power plants. For this reason, a comparison between the two solar options is also provided that include energy storage. Although electricity storage is more expensive than thermal storage, PV power remains a competitive option. Expenses related to O&M in solar thermal plant are about ten times higher than PV, an important factor resulting in higher energy cost. Based on data from proven commercial technologies, this study showed that PV holds a slight advantage even when energy storage is included.Il existe tr\ue8s peu de donn\ue9es comparant le rendement et le co\ufbt de la production d\u2019\ue9lectricit\ue9 solaire par des syst\ue8mes thermiques et photovolta\uefques (PV). Vu les progr\ue8s majeurs qu\u2019ont connus la technologie et le commerce, il est n\ue9cessaire d\u2019\ue9tablir une comparaison entre ces deux options d\u2019\ue9nergie solaire. Nous avons \ue9labor\ue9 un mod\ue8le simple pour comparer les co\ufbts de l\u2019\ue9lectricit\ue9 que repr\ue9sentent ces choix sans ajout d\u2019une source de carburant pour constituer des syst\ue8mes hybrides. Les co\ufbts en immobilisations ainsi que les co\ufbts de fonctionnement et d\u2019entretien (O&M) et d\u2019autres param\ue8tres provenant de grands parcs solaires existants sont utilis\ue9s pour \ue9tablir les co\ufbts r\ue9els de projets. Pour concurrencer les sources de production d\u2019\ue9lectricit\ue9 classiques, les technologies solaires doivent produire de l\u2019\ue9nergie \ue9lectrique de fa\ue7on distribuable afin de r\ue9pondre \ue0 la demande pendant les heures de pointe. Il existe diverses solutions de stockage d\u2019\ue9nergie. Malgr\ue9 son co\ufbt en immobilisations \ue9lev\ue9, l\u2019ajout de dispositifs de stockage de l\u2019\ue9nergie est consid\ue9r\ue9 comme \ue9tant une meilleure solution \ue0 long terme que les syst\ue8mes solaires hybrides dans les grandes centrales \ue9lectriques. C\u2019est pour cette raison que nous avons aussi inclus une comparaison des deux choix solaires qui comprend le stockage de l\u2019\ue9nergie. Bien que le stockage de l\u2019\ue9lectricit\ue9 soit plus dispendieux que le stockage thermique, l\u2019alimentation PV demeure une option concurrentielle. Les d\ue9penses de fonctionnement et d\u2019entretien li\ue9es aux centrales solaires thermiques sont pr\ue8s de dix fois plus \ue9lev\ue9es que celles du PV, ce qui en fait un facteur important entra\ueenant des co\ufbts plus \ue9lev\ue9s de l\u2019\ue9nergie. Bas\ue9e sur des technologies commerciales \ue9prouv\ue9es, cette \ue9tude prouve que le PV d\ue9tient un l\ue9ger avantage m\ueame si nous int\ue9grons le stockage de l\u2019\ue9nergie.Peer reviewed: YesNRC publication: Ye

Failure analysis in energy related materials and coatings - role of nanostructured materials for sustainable solutions

Improving performance and lifetime cost of current base materials and coating solutions requires detailed failure analysis. Materials corrosion has significant financial, environmental and safety impacts in the petrochemical and transportation sectors. Alternative materials have been recently developed to improve performance over cost ratio. Nanomaterials are introduced at even increased pace within components in numerous industrial sectors. In few cases, nanostructured materials and films improve the performance over cost ratio while reducing utilization of raw materials and environmental impact. In most cases, detailed failure analysis is important to quantify advantages and shortcomings of nanomaterials. In particular, detailed and complementary materials science and materials engineering investigation is recommended. This will allow better understanding of the relationship between the composition and structure in one hand and functional properties on the other hand.Peer reviewed: YesNRC publication: Ye

Nanoparticle technologies : from lab to market /

This book is a good introductory work to nanoparticle technology. It consists of nine complementary chapters that can be read independently. This book covers promising nanoparticles fabrication technologies with a focus on scalable processes. Integration of nanoparticles into 2D and 3D structures are covered in detail. The most promising applications of nanoparticles in the energy, optoelectronic and biomedical sectors are summarized and discussed. Current issues and challenges related to nanoparticles production and utilisation are also discussed in the book. Complete and simple overview of the fieldContains practical examples that makes the book also accessible for industrialists, engineers and managersChapters can be read relatively independently so experienced researchers can go directly to the them of interestAdvantages, drawbacks and challenges are described with practical examples.Descripció del recurs: el 26 de setembre de 2013.This book is a good introductory work to nanoparticle technology. It consists of nine complementary chapters that can be read independently. This book covers promising nanoparticles fabrication technologies with a focus on scalable processes. Integration of nanoparticles into 2D and 3D structures are covered in detail. The most promising applications of nanoparticles in the energy, optoelectronic and biomedical sectors are summarized and discussed. Current issues and challenges related to nanoparticles production and utilisation are also discussed in the book. Complete and simple overview of the fieldContains practical examples that makes the book also accessible for industrialists, engineers and managersChapters can be read relatively independently so experienced researchers can go directly to the them of interestAdvantages, drawbacks and challenges are described with practical examples.Includes bibliographical references and index.Dedication; Preface; 1. Nanoparticle fundamentals; 2. Wet production methods; 3. Dry production methods; 4. Nanoparticle assembling and system integration; 5. Clean energy; 6. Biomedical; 7. Optoelectronics; 8. Environmental and societal applications and implications; 9. Challenges and perspectives; IndexElsevie

Analysis and Multiobjective Optimization of a Machine Learning Algorithm for Wireless Telecommunication

There has been a fast deployment of wireless networks in recent years, which has been accompanied by significant impacts on the environment. Among the solutions that have been proven to be effective in reducing the energy consumption of wireless networks is the use of machine learning algorithms in cell traffic management. However, despite promising results, it should be noted that the computations required by machine learning algorithms have increased at an exponential rate. Massive computing has a surprisingly large carbon footprint, which could affect its real-world deployment. Thus, additional attention needs to be paid to the design and parameterization of these algorithms applied in order to reduce the energy consumption of wireless networks. In this article, we analyze the impact of hyperparameters on the energy consumption and performance of machine learning algorithms used for cell traffic prediction. For each hyperparameter (number of layers, number of neurons per layer, optimizer algorithm, batch size, and dropout) we identified a set of feasible values. Then, for each combination of hyperparameters, we trained our model and analyzed energy consumption and the resulting performance. The results from this study reveal a great correlation between hyperparameters and energy consumption, confirming the paramount importance of selecting optimal hyperparameters. A tradeoff between the minimization of energy consumption and the maximization of machine learning performance is suggested

Step-scan photoacoustic fourier transform and X-rays photoelectron spectroscopy of oil sands fine tailings : New structural insights

The chemical and physical properties of clay suspensions from oil sands have profound effect not only on the bitumen extraction process but also on the tailing treatment and reclamation. Step-scan Photoacoustic Fourier Transform Infrared (S\ub2PAS-FTIR) has been used to characterize the properties of clay suspensions. The photoacoustic spectral features of the fine solids (FS) fraction were found to vary drastically with the modulation frequency. This is attributed to the increase in the relative amount of bitumen-like matter in the bulk. A similar behavior was observed on the bi-wetted solid (BWS) fraction, in spite of the fact that the variation as a function of the modulation frequency is less significant. No such change is observed on hydrophobic solid (HPS) sample. These observations allow us to refine our pictorial image of the bitumen fraction materials structure. \ua9 2001 Published by Elsevier Science B.V.Peer reviewed: YesNRC publication: Ye

Development of a Reverse Logistics Modeling for End-of-Life Lithium-Ion Batteries and Its Impact on Recycling Viability—A Case Study to Support End-of-Life Electric Vehicle Battery Strategy in Canada

The deployment of a sustainable recycling network for electric vehicle batteries requires the development of an infrastructure to collect and deliver batteries to several locations from which they can be transported to companies for repurposing or recycling. This infrastructure is still not yet developed in North America, and consequently, spent electric vehicle batteries in Canada are dispersed throughout the country. The purpose of this reverse logistics study is to develop a spatial modeling framework to identify the optimal locations of battery pack dismantling hubs and recycling processing facilities in Canada and quantify the environmental and economic impacts of the supporting infrastructure network for electric vehicle lithium-ion battery end-of-life management. The model integrates the geographic information system, material flow analysis for estimating the availability of spent battery stocks, and the life cycle assessment approach to assess the environmental impact. To minimize the costs and greenhouse gas emission intensity, three regional recycling clusters, including dismantling hubs, recycling processing, and scrap metal smelting facilities, were identified. These three clusters will have the capacity to satisfy the annual flow of disposed batteries. The Quebec–Maritimes cluster presents the lowest payload distance, life-cycle carbon footprint, and truck transportation costs than the Ontario and British Columbia–Prairies clusters. Access to end-of-life batteries not only makes the battery supply chain circular, but also provides incentives for establishing recycling facilities. The average costs and carbon intensity of recycled cathode raw materials are CAD 1.29/kg of the spent battery pack and 0.7 kg CO2e/kg of the spent battery pack, respectively, which were estimated based on the optimization of the transportation distances

A game theoretic approach to contract-based enviro-economic coordination of wood pellet supply chains for bioenergy production

Abstract Wood pellets have gained global attention due to their economic availability and increasing demand for bioenergy as part of sustainable energy solutions. Management of the wood pellet supply chains, from feedstock harvesting to bioenergy conversion, is critical to ensure competitiveness in the energy markets. In this regard, wood pellets supply chain coordination can play a strategic role in enhancing the efficiency and reliability of bioenergy generation. This study proposes a contract-based coordination mechanism for wood pellet supply chains and compares its performance in alternative centralized and decentralized decision-making structures. A bi-level nonlinear game-theoretic approach with two economic and environmental objective functions is developed. It utilizes the concept of life cycle assessment in a Stackelberg leader–follower game to obtain the bioenergy equilibrium solutions. Further, this study examines the case of wood pellet supply chains in three remote Canadian communities. The aim is to showcase the practicality and significance of the proposed approach and interpret the findings. By focusing on these communities, the crucial role of supply chain coordination in fostering sustainable development, particularly, in the context of bioenergy generation is emphasized. The study colludes by advocating a number of avenues for future research

Observation of surface enhanced IR absorption coefficient in alkanethiol based self-assembled monolayers on GaAs(001)

Alkanethiol self-assembled monolayers (SAMs) of various methylene group chain lengths [HS\u2013(CH\u2082)n\u2013CH\u2083] (n=9,11,13,15,17) were fabricated on the GaAs(001) surface followed by characterization using Fourier transform infrared spectroscopy. Modal analysis of the CH\u2082 stretching mode region (2800\u20133000 cm\u207b\ub9) showed that linear scaling of the n-dependent factors accurately reproduced the spectral data, supporting a chain-length consistent physical model upon which a measurement of the absorption coefficient was based. Evaluated from the linearity of the absorbance data, a peak coefficient of 3.5 x 10\u2074 cm\u207b\ub9 was obtained and a domain for ordered self-assembly was assigned for values n>9. Compared with measurements of the absorption coefficient made in the liquid phase, the SAM phase coefficient was determined to be about six times greater. This enhancement effect is discussed in terms of contributions relating to the locally ordered environment and is largely attributed to the chemical properties of the interface. We believe this to be the first demonstration of IR spectral enhancement of a molecular species chemisorbed on the semiconductor surface.Peer reviewed: YesNRC publication: Ye

Interfacial Analysis of n-Alkanethiol Self-assembled Monolayers on GaAs(001) by Angle-Resolved X-ray Photoelectron Spectroscopy

The compositional schoichiometry and structural morphology of n-alkanethiol self-assembled monolayers (SAMs) formed on the GaAs(001) surface was investigated by Angle-Resolved X-ray Photoelectron Spectroscopy (ARXPS). In order to decompose high resolution ARXPS spectra, synthetic lineshape calibration was first referred to Ar-ion beam sputtered GaAs using low-asymmetry Doniach-Sunjic lineshape profiles. Following SAM formation, the As-S chemical state was located at +1.8 eV from GaAs in the As 3d region in agreement with data following GaAs passivation with inorganic sulphides, and was estimated to represent a bond fraction of 30-50% relative to the total number of S-GaAs bonds. The surface was observed to be Ga-rich, but no Ga-S interface component could be resolved. The surface density of elemental As was quantified using fractional overlayer modeling. A value of 2.9-4.2x1o(14) cm(-2) was obtained, which represents a monolayer fraction of 35-50%. Similarly, fractional overlayer modeling was used to estimate the SAM uniformity, and a value of 92% was achieved.NRC publication: Ye