Multi-temporal Optimal Power Flow for Assessing the Renewable Generation Hosting Capacity of an Active Distribution System

International audienceThe detailed modeling of distribution grids is expected to be critical to understand the current functionality limits and necessary retrofits to satisfy integration of massive amounts of distributed generation, energy storage devices and the electric consumption demand of the future. Due to the highly dimensional non-convex characteristics of the power flow equations, convex relaxations have been used to ensure an efficient calculation time. However, these relaxations have been proven to be inexact during periods of high RES injection. In this paper additional linear constraints were introduced in the power flow formulation to guaranty an exact relaxation. This convex relaxation is then applied within a multi-temporal algorithm in order to evaluate the benefits of storage grid integration. The case study of a French medium voltage feeder is studied to evaluate the maximum capacity of the grid to host RES sources and the advantages of storage systems in reducing curtailment of RES

On the impact of socio-economic factors on power load forecasting

International audienceIn this paper, we analyze a public dataset of electricity consumption collected over 3,800 households for one year and half. We show that some socioeconomic factors are critical indicators to forecast households' daily peak (and total) load. By using a random forests model, we show that the daily load can be predicted accurately at a fine temporal granularity. Differently from many state-of-the-art techniques based on support vector machines, our model allows to derive a set of heuristic rules that are highly interpretable and easy to fuse with human experts domain knowledge. Lastly, we quantify the different importance of each socioeconomic feature in the prediction task

Synthèse CIRED 2015 Rapport sur le Congrès International des Réseaux Electriques de Distribution

International audienceUne synthèse globale de la conférence CIRED 2015 fait par des doctorants de plusieurs écoles

On a class of 4D Kahler bases and AdS_5 supersymmetric Black Holes

We construct a class of toric Kahler manifolds, M_4, of real dimension four, a subset of which corresponds to the Kahler bases of all known 5D asymptotically AdS_5 supersymmetric black-holes. In a certain limit, these Kahler spaces take the form of cones over Sasaki spaces, which, in turn, are fibrations over toric manifolds of real dimension two. The metric on M_4 is completely determined by a single function H(x), which is the conformal factor of the two dimensional space. We study the solutions of minimal five dimensional gauged supergravity having this class of Kahler spaces as base and show that in order to generate a five dimensional solution H(x) must obey a simple sixth order differential equation. We discuss the solutions in detail, which include all known asymptotically AdS_5 black holes as well as other spacetimes with non-compact horizons. Moreover we find an infinite number of supersymmetric deformations of these spacetimes with less spatial isometries than the base space. These deformations vanish at the horizon, but become relevant asymptotically.Comment: 34 pages, 3 figures. v2: formula (8.35) and other minor typos corrected; references added; accepted for publication in JHE

Using Customer-related Data to Enhance E-grocery Home Delivery

International audiencePurpose: The development of e-grocery allows people to purchase food online and benefit from home delivery service. Nevertheless, a high rate of failed deliveries due to the customer’s absence causes significant loss of logistics efficiency, especially for perishable food. This paper proposes an innovative approach to use customer-related data to optimize e-grocery home delivery. The approach estimates the absence probability of a customer by mining electricity consumption data, in order to improve the success rate of delivery and optimize transportation.Design/methodology/approach: The methodological approach consists of two stages: a data mining stage that estimates absence probabilities, and an optimization stage to optimize transportation.Findings: Computational experiments reveal that the proposed approach could reduce the total travel distance by 3% to 20%, and theoretically increase the success rate of first-round delivery approximately by18%-26%.Research limitations/implications: The proposed approach combines two attractive research streams on data mining and transportation planning to provide a solution for e-commerce logistics.Practical implications: This study gives an insight to e-grocery retailers and carriers on how to use customer-related data to improve home delivery effectiveness and efficiency.Social implications: The proposed approach can be used to reduce environmental footprint generated by freight distribution in a city, and to improve customers’ experience on online shopping.Originality/value: Being an experimental study, this work demonstrates the effectiveness of data-driven innovative solutions to e-grocery home delivery problem. The paper provides also a methodological approach to this line of research

Fracture strength of flared bovine roots restored with different intraradicular posts

OBJECTIVE: The aim of this study was to evaluate the fracture strength and failure mode of flared bovine roots restored with different intraradicular posts. MATERIAL AND METHODS: Fifty bovine incisors with similar dimensions were selected and their roots were flared until 1.0 mm of dentin wall remained. Next, the roots were allocated into five groups (n=10): GI- cast metal post-and-core; GII- fiber posts plus accessory fiber posts; GIII- direct anatomic post; GIV- indirect anatomic post and GV- control (specimens without intraradicular post). A polyether impression material was used to simulate the periodontal ligament. After periodontal ligament simulation, the specimens were subjected to a compressive load at a crosshead speed of 0.5 mm/min in a servo-hydraulic testing machine (MTS 810) applied at 135º to the long axis of the tooth until failure. The data (N) were subjected to ANOVA and Tukey's post-hoc test (α=0.05). RESULTS: GI and GIV presented higher fracture strength (p;0.05) from GI, GII and GIV. Control specimens (GV) produced the lowest fracture strength mean values (

Planeamiento estratégico del sector agropecuario de la Región Ucayali

El presente trabajo consiste en el análisis del sector agropecuario de la región Ucayali. A partir de este, se hace un planeamiento estratégico siguiendo el Modelo Secuencial del Proceso Estratégico (D’Alessio, 2012), lo cual permitirá el desarrollo y crecimiento de la región y su población. Ucayali posee una gran riqueza hidrológica, variedad de cultivos (maíz amarillo duro, café, camu camu, arroz con cáscara, plátanos, cacao, palma aceitera, etc.), una gran cantidad de tierras forestales, crianza de ganado (bovino, cerdos y avícola) y derivados pecuarios; sin embargo, no cuenta con suficiente industrialización en ambos subsectores. Para contrarrestar el bajo desarrollo industrial y tecnológico, existen diversas asociaciones de investigación que contribuyen con el crecimiento del sector y su sostenibilidad. Entre ellas, se encuentran el Consorcio para el Desarrollo Sostenible de Ucayali (CODESU), el Instituto Nacional de Investigación Agraria (INIA) y el Instituto de Investigación de la Amazonía Peruana (IIAP). Además, se cuenta con la presencia de una alianza mundial de investigación, el Group on International Agricultural Research (CGIAR), que reúne a diversas organizaciones. Por medio del presente estudio, se llegó a la conclusión de la necesidad de una mayor inversión en industrialización, tecnología, investigación, infraestructura, mejora de mano de obra y capacitaciones; la presencia de autoridades que velen por el crecimiento y desarrollo de la región; el fortalecimiento de la industria por medio de la mejora en la producción; el valor agregado; la diversificación de productos; la inserción en nuevos mercados; la ejecución de planes de gestión eficiente de conservación de suelos, especies y recursos hidrológicos. Se han considerado estos factores en el planteamiento de objetivos a largo y corto plazo, teniendo como visión aumentar la participación del sector agropecuario a nivel nacional, y ser una de las cinco principales regiones productoras y abastecedoras en el PerúThe present study consists in the analysis of the agricultural and livestock sector in the Ucayali region in order to design a strategic plan according to Sequential Model of Strategic Process (D’Alessio, 2012) that will enable the development and growth of this region and its population. Ucayali has a wide variety of hydrologic sources, as well as crops (hard yellow corn, coffee, camu camu, paddy rice, bananas, rice, cocoa, oil palm, etc.), a vast forest land, cattle raising (bovine, pigs and poultry) and livestock derivatives; but it has not yet been provided with modern industrial technology in both sub sectors. To counteract Ucayali’s industrial and technological low development, there are several research partnerships that contribute to the sector's growth and sustainability, such as the Consortium for Sustainable Development of Ucayali (CODESU), the National Agricultural Research Institute (INIA) and the Research Institute of the Peruvian Amazon (IIAP), it also has the presence of the Consultative Group on International Agricultural Research (CGIAR), a global research partnership that groups a diverse range of organizations. Through this study, it was concluded that it is necessary to have a greater investment in industrialization, technology, research, infrastructure, labor and training improvement, as well as to have the authorities support to ensure the growth and development of the region, strengthening the industry through enhanced production, added value, product diversification, new markets entry and the implementation of efficient management plans related to soil, species and water resources conservation. These factors have been considered for the short and long term objectives, having as vision the increase of Ucayali’s participation in the national agricultural and livestock sector and thus become one of the five main producers and suppliers regions in Peru.Tesi

Fate of drugs during wastewater treatment

This is the post-print version of the final paper published in TrAC Trends in Analytical Chemistry. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.Recent trends in the determination of pharmaceutical drugs in wastewaters focus on the development of rapid multi-residue methods. This review addresses recent analytical trends in drug determination in environmental matrices used to facilitate fate studies. Analytical requirements for further fate evaluation and tertiary process selection and optimization are also discussed.EPSRC, Northumbrian Water, Anglian Water, Severn Trent Water, Yorkshire Water, and United Utilities

Discovery of Samarium, Europium, Gadolinium, and Terbium Isotopes

Currently, thirty-four samarium, thirty-four europium, thirty-one gadolinium, and thirty-one terbium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.Comment: To be published in At. Data Nucl. Data Table