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Lopes V.S.,Energy Research Company | Borges C.L.T.,Federal University of Rio de Janeiro
IEEE Transactions on Sustainable Energy | Year: 2015

The purpose of this paper is to assess the impact of the integration of wind generation, together with small hydropower plants (SHPs), in the reliability of the power system. In order to preserve the characteristics of the time series of the variable energy sources (wind and river inflows) and the variable load, the analyses are based on the sequential Monte Carlo simulation. By calculating the reliability indices, we intend to evaluate how the uncertainty of wind energy production impacts on system planning, especially with the reduction of capacity of reservoirs associated with SHPs. We also intend to evaluate the existence of complementarity between wind and hydro-generation, or even between different wind generation and/or the load. Finally, we intend to analyze how the correlation between these energy sources can benefit the supply of the future foreseen demand. © 2010-2012 IEEE. Source

Borges C.L.T.,Federal University of Rio de Janeiro | Martins V.F.,Energy Research Company
International Journal of Electrical Power and Energy Systems | Year: 2012

This paper presents a methodology for active distribution networks dynamic expansion planning based on Genetic Algorithms, where Distributed Generation integration is considered together with conventional alternatives for expansion, such as, rewiring, network reconfiguration, installation of new protection devices, etc. All aspects related to the expansion planning problem, such as multiple objective analysis, reliability constraints, modeling under uncertainties of demand and power supplied by Distributed Generation units and multistage planning, which are usually dealt with separately, are considered in an integrated model. Uncertainties are represented through the use of multiple scenario analysis. Multiple stages are incorporated by an algorithm based on the pseudo-dynamic programming theory. Results obtained with a test system and with an actual large scale system are presented and demonstrate the flexibility of applying the model for different purposes active network planning. © 2011 Elsevier Ltd. All rights reserved. Source

Wolf T.,University of Stuttgart | Neumann P.,University of Stuttgart | Nakamura K.,Energy Research Company | Sumiya H.,Sumitomo Electric Industries | And 3 more authors.
Physical Review X | Year: 2015

Nitrogen-vacancy (NV) defect centers in diamond are promising solid-state magnetometers. Single centers allow for high-spatial-resolution field imaging but are limited in their magnetic field sensitivity. Using defect-center ensembles, sensitivity can be scaled with √N p when N is the number of defects. In the present work, we use an ensemble of N ~ 1011 defect centers within an effective sensor volume of 8.5 × 10-4 mm3 for sensing at room temperature. By carefully eliminating noise sources and using highquality diamonds with large NV concentrations, we demonstrate, for such sensors, a sensitivity scaling as 1= √t p, where t is the total measurement time. The associated photon-shot-noise-limited magnetic-field sensitivity for ac signals of f = 20 kHz is 0.9 pT= √Hz. For a total measurement time of 100 s, we reach a standard deviation of about 100 fT. Further improvements using decoupling sequences and material optimization could lead to fT= √Hz p sensitivity. Source

Wang B.,Energy Research Company | Lu X.-Y.,The Hong Kong Institute of Education | Tang Y.,South University of Science and Technology of China
Journal of Materials Chemistry A | Year: 2015

In this study, snowflake-shaped Co3O4 nanosheets (Co3O4-SF) are successfully fabricated by a facile ammonia-assisted hydrothermal route followed by calcination at 450 °C. Material characterizations indicate that the as-prepared Co3O4-SF shows an ultrathin structure with 10 μm width and 100 nm thickness, suggesting micro-/nanostructures and a high aspect ratio of 100. Reactant concentration and reaction duration are considered as important synthesis parameters for snowflake-shaped Co3O4 fabrication. It is also found that ammonia plays critical roles in the formation of the snowflake structure. By simply manipulating the ammonia amount, the material structure can be easily changed to hexagonal nanosheets (Co3O4-HX). More importantly, when Co3O4 anodes with these two interesting structures are evaluated in a coin cell, the snowflake-shaped Co3O4 electrode delivers remarkable capacities (1044 mA h g-1 at 500 mA g-1) with better retention (86-98% at 500-1000 mA g-1) after 100 cycles and excellent rate performance (977 mA h g-1 at 3000 mA g-1) at various current densities. Due to the unique structure and properties, snowflake-shaped Co3O4 anodes with superior battery performance demonstrate great potential in lithium ion batteries. © The Royal Society of Chemistry.2015. Source

Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2011

Energy Research Company (ERCo) proposes the development of an instrument to improve laser-decoating processes through novel real-time control technology. The technology allows for precise and selective removal of the desired coating layer while preserving any underlying coatings and the base material. Because of the real-time nature of the proposed device, using the instrument will not result in a reduction in the decoating rate. The quality of the decoating process will thereby be greatly improved while throughput of the laser decoating system will be unaffected. ERCo has demonstrated the technique in its laboratory and has shown that very accurate coating removal can be obtained. In Phase I, ERCo will demonstrate the device"s ability to automatically and accurately control the removal of topcoat and/or primer layers while preserving underlying layers and the substrate material. BENEFIT: The benefits are the accurate removal of coatings while preserving underlying layers and substrate materials with an instrument that is inexpensive and self contained. This will result in reduced maintenance costs for decoating operations. The federal and civilian markets are large. The federal market includes paint and coating removal from ships, aircraft, and related equipment. The civilian market includes paint removal from commercial jetliners, ships, and bridge maintenance.

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