A comparative study of charging assumptions in electric vehicle routing problems

International audienceElectric vehicle routing problems (eVRPs) extend classical routing problems to consider the limited driving range of electric vehicles. In general, this limitation is overcome by introducing planned detours to battery charging stations. Most existing eVRP models rely on one (or both) of the following assumptions: (i) the vehicles fully charge their batteries every time they reach a charging station, and (ii) the battery charge level is a linear function of the charging time. In practical situations, however, the amount of charge is a decision variable, and the battery charge level is a concave function of the charging time. In this research we extend current eVRP models to consider partial charging and nonlinear charging functions. We present a computational study comparing our assumptions with those commonly made in the literature. Our results suggest that neglecting partial and nonlinear charging may lead to infeasible or overly expensive solutions

Assessment of the methane emission for different typologies of fattening swine facilities in the department of Antioquia – Colombia

The explosive growth of swine production at high stocking densities in confinement farming worldwide, has raised concerns the environmental impact, health and livestock productivity and the production of associated gases in this type of large-scale farms. The aim of this paper was to study the methane gas concentration and emissions of ten different typologies of swine production installations. The facilities were in the department of Antioquia - Colombia, they were located between 800–2,300 meters above sea level (m.a.s.l.) of heights, they mainly employed natural ventilation as refrigeration strategy and they were used for pigs in fattening stage. Methane measurements were taken at animal height. Sensors were located at intermediate points of the ventilation inlet and outlet areas. The behaviour of methane concentration and emission of the facilities were analysed along with the correlation and temporal evolution of climatic variables, comfort indices and construction typologies. The information was analysed using descriptive statistics, analysis of variance (ANOVA) and principal component analysis (PCA). Were found an average of CH4 Emission Rate (ER) per facility (kg year-1 ) of 607.9, Global Warming Potential (GWP) per facility (kg year-1 ) of 15,197.42 and significant correlations between ER and cleaning frequency (CF), animal unit (AU), air flow (Q), animal density(AD) and relative humidity (RH) were evidenced. This is the first research reported in Colombia, that will be important to create some governmental policies

Specific increase of a mitochondrial RNA transcript in chronic ethanol-fed rats

AbstractAn in vitro transcription system utilizing isolated mitochondria has been used to study the effect of chronic ethanol consumption on liver mitochondrial DNA transcription. The results obtained showed an overall increase of RNA synthesis and a dramatic accumulation of a discrete polyadenylated RNA species. This effect is a consequence of the chronic ethanol consumption since these changes do not occur when isolated control mitochondria are incubated in the presence of ethanol

Techno-economic Feasibility of A Trust and Grid-aware Coordination Scheme

The massive penetration of active customers throughout Home Energy Management Systems (HEMS) may cause adverse effects on the power grid, including rebound peaks, instabilities, and power congestion. The concept of coordination has arisen in literature to mitigate these effects and relieve power grid stress. Their advantages have been discussed for different market types as well as at different grid scales. However, it is imperative to develop proofs-of-concept and test not only the economic feasibility of such programs but also the technical one. This paper presents a cosimulation-based framework that facilitates economic and technical studies for coordination programs. A case study is presented, with eighteen residential users and a local coordinator within a Stackelberg game. At the customer level, flexibility is achieved through electric thermal storage (ETS). The program exploits salient features of blockchain algorithms to increase security at the demand aggregation level. The technical feasibility was evaluated through the Peak-to-average (PAR) ratio, active power losses, and the voltage profile using power flow methods over the IEEE 33-node feeder. This study’s findings demonstrate the coordination programs’ ability to bring economic benefits and reduce the PAR. Furthermore, they suggest that although coordination programs can assist in flattening the power profile, they could create adverse effects on the power grid in critical scenarios

Ecofisiología de los plátanos en zona de altitud de Colombia en relación con su susceptibilidad a las cercosporiasis: informe final.

El cultivo del plátano en Colombia se constituye en un renglón de importancia desde el punto de vista alimentario y social. Una de las enfermedades de importancia en este cultivo es la sigatoka negra; en este estudio se analiza la susceptibilidad del cultivo de plátano a esta enfermedad, se analizó igualmente su conocimiento epidemiológico y el manejo de esta enfermedad para la zona cafetera de Colombia.Plátano-Musa sapientu

Casuística del Centro de Diagnóstico Veterinario Tulenapa (Carepa) 1976-1988.

Se recopilas las actividades realizadas en el Centro de Diagnóstico del ICA, en Tulenapa, entre agosto de 1976 a diciembre de 1988, incluyendo la patología animal diagnosticada en las distintas especies de la región de Urabá (Urabá Chocoano y Antioqueño), con el propósito de dar a conocer la situación sanitaria a las directivas del ICA y a los usuarios. Según lo analizado, se destacan las serologías para diagnóstico de brucelosis en la especie bovina (51.186 casos). El mayor número de predios atendidos/especie correspondió a la bovina (72.4 por ciento) del total de fincas. De las enfermedades/especie según su naturaleza etiopatológica, las parasitarias fueron de mayor prevalencia, expresada en porcentajes así: bovinos (70.7), equinos (33.8), porcinos (41.0), ovinos y caprinos (70.5), aves de corral (30.9) y caninos (35.0). De las campañas sanitarias efectuadas/especie, se encontraron focos de las siguientes enfermedades: bovinos (fiebre aftosa 30) y rabia paralítica (31), equinos (encefalitis equina venezolana 8), porcinos (cólera porcino 8) y en aves (new-castle 8). En brucelosis se observaron varios aspectos, entre ellos: de los 51.186 bovinos estudiados, 1.699 resultaron reactores al antigeno de Bang (prevalencia ponderada 3.3 por ciento), de 3.046 fincas examinadas, 412 fueron positivas (13.5 por ciento), en equinos (prevalencia de 27.9 por ciento), porcinos (9.5 por ciento), ovinos y captrinos (4.1 por ciento) y en la especie humana (6.3 por ciento). Referente al hato libre, iniciado en 1986 en la zona de Urabá, se logró un total de 166 predios involucrados en el programa a diciembre de 1988, de los cuales 69 poseen certificado, siendo Frontino el sector con mayor número de fincas (26) dentro del programa y Dabeiba con el mayor número de predios (11) con certificadoOvinos-Ganado ovino - Ovis arie

Optimal Power Flow in Direct Current Networks Using the Antlion Optimizer

This document presents a solution method for optimal power flow (OPF) problem in direct current (DC) networks by implementing a master-slave optimization methodology that combines an antlion optimizer (ALO) and a power flow approach based on successive approximation (SA ). In the master stage, the ALO determines the optimal amount of power to be delivered by all the distributed generators (DGs) in order to minimize the total power losses in the distribution lines of the DC network. In slave stage, the power flow problem is solved considering constant power loads and power outputs of DGs as constants. To validate the effectiveness and robustness of the proposed model, two additional comparative methods were implemented: particle swarm optimization (PSO) and black hole optimization (BHO). Two distribution test feeders (21 and 69 nodes) were simulated under different scenarios of distributed power generation. The simulations, conducted in MATLAB 2018$b$, show that the proposed method (ALO) presents a better balance between power loss minimization and computational time required to find the optimal solution regardless of the size of the DC network

Villafranchian large mammals from the Iberian Peninsula: paleobiogeography, paleoecology and dispersal events

The Pleistocene of the Iberian Peninsula is currently a focus of intense paleontological, archaeological and geological research. To a large extent, these inquiries are intended to decipher the ecological factors that might have conditioned early Homo dispersals into the European continent during the late Early Pleistocene. In this respect, the research carried out during the last twenty years in several areas of the Iberian Peninsula (the Guadix-Baza Basin, the Sierra de Atapuerca, the Vallparadís Section and the Banyoles-Besalú Basin) have yielded a large amount of new significant data. Here we review such data and provide for the first time a comprehensive synthesis from a faunal, geologi­cal and paleoecological perspectives, by focusing on the relationship between paleoenvironmental conditions and early human dispersals during the late Early Pleistocene in the Iberian Peninsula. In particular, the Iberian fossil record of Early to Late Villafranchian large mam­mals is synthesized, on the basis of recent publications and unpublished data collected by the authors during the last five years, in order to provide the adequate faunal and paleocological framework for understanding the factors that limited or conditioned human dispersal events.El Pleistoceno de la Península Ibérica es actualmente foco de intensa investigación paleontológica, arqueológica y geológica. En gran medida, estos trabajos están encaminados a descifrar los factores ecológicos que podrían haber condicionado las dispersiones de los Homo iniciales hacia Europa durante el Pleistoceno inferior. En este sentido, la investigación realizada durante los últimos veinte años en diversas zonas de la Península Ibérica (la Cuenca de Guadix-Baza, la Sierra de Atapuerca, la Sección de Vallparadís y la Cuenca de Banyoles- Besalú) ha proporcionado una gran cantidad de nuevos datos significativos. Aquí revisamos estos datos y se proporciona por primera vez una síntesis exhaustiva desde una perspectiva paleontológica, paleoecológica y geológica, centrándonos en las relaciones entre las condi­ciones paleoambientales y las dispersiones de los primeros humanos en el Pleistoceno inferior de la Península Ibérica. Concretamente, se sintetiza el registro fósil ibérico de grandes mamíferos villafranquienses en base a publicaciones recientes y datos inéditos recopilados por los autores en los últimos cinco años, para así proporcionar el marco faunístico y paleoecológico adecuado para comprender los factores que limitaron o condicionaron los eventos de dispersión humana

Optimal Power Dispatch in Direct Current Networks to Reduce Energy Production Costs and CO 2 Emissions Using the Antlion Optimization Algorithm

In this study, we present a master–slave methodology to solve the problem of optimal power dispatch in a direct current (DC) microgrid. In the master stage, the Antlion Optimization (ALO) method solves the problem of power dispatch by the Distributed Generators (DGs); in the slave stage, a numerical method based on successive approximations (SA) evaluates the load flows required by the potential solutions proposed by the ALO technique. The objective functions in this paper are the minimization of energy production costs and the reduction of CO 2 emissions produced by the diesel generators in the microgrid. To favor energy efficiency and have a lower negative impact on the environment, the DC microgrids under study here include three DGs (one diesel generator and two generators based on renewable energy sources, i.e., solar energy and wind power) and a slack bus connected to a public electrical grid. The effectiveness of the proposed ALO–SA methodology was tested in the 21- and 69-bus test systems. We used three other optimization techniques to compare methods in the master stage: particle swarm optimization, continuous genetic algorithm, and black hole optimization. Additionally, we combined SA with every method to solve the load flow problem in the slave stage. The results show that, among the methods analyzed in this study, the proposed ALO–AS methodology achieves the best performance in terms of lower energy production costs, less CO 2 emissions, and shorter computational processing times. All the simulations were performed in MATLAB. © 2021, King Fahd University of Petroleum & Minerals.Ocampo-Toro, J. A., Garzon-Rivera, O. D., Grisales-Noreña, L. F., Montoya-Giraldo, O. D., & Gil-González, W. (2021). Optimal Power Dispatch in Direct Current Networks to Reduce Energy Production Costs and CO 2 Emissions Using the Antlion Optimization Algorithm. Arabian Journal for Science and Engineering, 46(10), 9995-10006