STUDY OF SENSITIVITY OF THE PARAMETERS OF A GENETIC ALGORITHM FOR DESIGN OF WATER DISTRIBUTION NETWORKS

The Genetic Algorithms (GAs) are a technique of optimization used for water distribution networks design. This work has been made with a modified pseudo genetic algorithm (PGA), whose main variation with a classical GA is a change in the codification of the chromosomes, which is made of numerical form instead of the binary codification. This variation entails a series of special characteristics in the codification and in the definition of the operations of mutation and crossover. Initially, the work displays the results of the PGA on a water network studied in the literature. The results show the kindness of the method. Also is made a statistical analysis of the obtained solutions. This analysis allows verifying the values of mutation and crossing probability more suitable for the proposed method. Finally, in the study of the analyzed water supply networks the concept of reliability in introduced. This concept is essential to understand the validity of the obtained results. The second part, starting with values optimized for the probability of crossing and mutation, the influence of the population size is analyzed in the final solutions on the network of Hanoi, widely studied in the bibliography. The aim is to find the most suitable configuration of the problem, so that good solutions are obtained in the less time

Determinación del eje de la carretera y la distancia de visibilidad utilizando datos GPS y herramientas SIG

Hoy en día, tanto en el proceso de diseño de las carreteras como en el análisis del funcionamiento de las ya construidas, se está dando cada vez más importancia a la seguridad vial. Entre los distintos aspectos que se consideran se encuentra la distancia de visibilidad. Por otra parte, uno de los problemas que aparecen en la práctica al tratar de analizar carreteras en servicio es la falta de datos de la geometría del eje que estén actualizados y tengan la precisión requerida. En esta comunicación se presenta un procedimiento para determinar el eje de la carretera mediante información GPS y calcular la distancia de visibilidad aplicando herramientas SIG. El procedimiento se ha aplicado a un tramo de carretera convencional de doble sentido de circulación. El método propuesto puede ser especialmente útil en aquellas carreteras en servicio y de las que, por no contar con la información sobre su trazado (original o posteriores modificaciones), no es posible utilizar los programas de diseño de carreteras para el cálculo de la distancia de visibilidad.Nowadays road safety aspects are very important, both for the designing process and for the analysis of already built roads. Sight distance is one of the most important road safety aspects to consider. On the other hand, the geometric definition of already built roads is one of the most difficult issues that arise in practice. This road geometry must be accurate and up to date. In this paper, a procedure to determine the alignment of a road using a GPS and to calculate sight distances using GIS tools is presented. Also, the use of this procedure in a two-lane rural road is described. The proposed method can be especially useful for those roads whose design data are not available because, on them, road design software could not be used for sight distance calculation

Critical radius for hot-jet ignition of hydrogen-air mixtures

This study addresses deflagration initiation of lean and stoichiometric hydrogen–air mixtures by the sudden discharge of a hot jet of their adiabatic combustion products. The objective is to compute the minimum jet radius required for ignition, a relevant quantity of interest for safety and technological applications. For sufficiently small discharge velocities, the numerical solution of the problem requires integration of the axisymmetric Navier–Stokes equations for chemically reacting ideal-gas mixtures, supplemented by standard descriptions of the molecular transport terms and a suitably reduced chemical-kinetic mechanism for the chemistry description. The computations provide the variation of the critical radius for hot-jet ignition with both the jet velocity and the equivalence ratio of the mixture, giving values that vary between a few tens microns to a few hundred microns in the range of conditions explored. For a given equivalence ratio, the critical radius is found to increase with increasing injection velocities, although the increase is only moderately large. On the other hand, for a given injection velocity, the smallest critical radius is found at stoichiometric conditions

New energy sources: Blue energy study in Central America

The following article has been submitted to/accepted by Journal of Renewable and Sustainable Energy. After it is published, it will be found at http://dx.doi.org/10.1063/1.4976326.Blue energy or salinity difference energy takes advantage of the free energy released in the mixture of two solutions with different salinity concentrations as it happens continuously in river mouths. Among the large number of available techniques that aim to harness blue energy, capmix (or capacitive mixing) methods allow to directly extract electrical energy without the need of any electromechanical converter such as turbines or heat engines. The main goal of this article is to analyze the potential of blue energy by capmix methods in Central America. So far, blue energy studies have been principally carried out in countries from the global North. Therefore, we describe experimental results with real sea and river waters from the Gulf of Fonseca, an area of special interest due to its hydrographic richness, which is situated among Honduras, El Salvador and Nicaragua. An electrochemical cell, which consists of a pair of activated carbon electrodes coated with cationic and anionic polyelectrolyte layers respectively, is used in the experiments. The cell voltage in open circuit (OCV) is used as a measure of the performance of the capmix process. It is found that the OCV is larger when natural river water is used instead of low salinity NaCl solutions. The rainy season in which the experiments were performed reduced the ionic content of the river, increasing the salinity difference with ocean waters. The feasibility of capmix as a means of clean energy production is discussed.Eureka SD Project (agreement number 2013-2591), Erasmus Mundus programme of the European Union.Ministerio de Economía y Competitividad of Spain (Project FIS2013-47666-C3- 1-R)Junta de Andalucía (Spain) project PE-2012- FQM0694EU FEDER FUND

High-temperature anti-Invar behavior of gamma-Fe precipitates in Fe_xCu_(100-x) solid solutions: Ferromagnetic phases

High-temperature magnetization and neutron diffraction measurements on metastable Fe_xCu_(100-x) solid solutions have recently shown to imply that γ-Fe precipitates present ferromagnetic anti-Invar behavior. For this reason, we have studied the ferromagnetic phases of γ-Fe in moment-volume parameter space, using the general potential linearized-augmented plane-wave method and the fixed spin moment procedure in order to calculate the corresponding total energy. We find that only two ferromagnetic phases (one related to a low- spin state and the other to a high-spin state) can exist and even coexist in limited volume ranges (3.55-3.59 Å). Hence, our results provide a "revisited" version of the local spin density calculations used in the early article by Moruzzi [Phys. Rev. B 34, 1784 (1986)]. In addition, the fixed spin moment method-using an energy-moment-volume space representation-allows us to conclude that the high-spin state is the ground state of the gamma-Fe precipitates, as the anti-Invar behavior is an intrinsic property of these states. This simple scenario seems to adequately describe the perplexing phenomenology recently observed on Fe_xCu_(100-x) solid solutions

SEOM clinical guidelines for the treatment of head and neck cancer (2020)

Head and neck cancers (HNC) are defined as malignant tumours located in the upper aerodigestive tract and represents 5% of oncologic cases in adults in Spain. More than 90% of these tumours have squamous histology. In an effort to incorporate evidence obtained since 2017 publication, the Spanish Society of Medical Oncology (SEOM) presents an update of the squamous cell HNC diagnosis and treatment guideline. Most relevant diagnostic and therapeutic changes from the last guideline have been updated: introduction of sentinel node biopsy in early oral/oropharyngeal cancer treated with surgery, concomitant radiotherapy with weekly cisplatin 40 mg/m2 in the adjuvant setting, new approaches for HPV-related oropharyngeal cancer and new treatments with immune-checkpoint inhibitors in recurrent/metastatic disease

Malformaciones venosas orofaciales de bajo flujo: esclerosis endoluminal con láser de diodo

ResumenIntroducciónLas anomalías vasculares son procesos frecuentes que se localizan en más del 50% de los casos en la región de la cabeza y el cuello. Las técnicas clásicas de tratamiento, tales como la cirugía y la esclerosis química, han dado paso a modernas técnicas menos invasivas, tales como el láser Nd:YAG. Por otra parte, se ha utilizado con éxito el láser de diodo (980 nm) para el tratamiento de varices mediante esclerosis endoluminal. Nuestra propuesta es la utilización del láser de diodo (λ 980 nm) para provocar una esclerosis por fotocoagulación intralesional de las malformaciones venosas de bajo flujo dada la capacidad de este láser de ser transmitido por fibra óptica.ObjetivoExponer nuestros resultados en el tratamiento de malformaciones venosas de bajo flujo (MVBF) orofaciales mediante la terapéutica de esclerosis endoluminal con láser de diodo.Material y métodosRevisamos 84 pacientes que presentaban MVBF orofaciales tratados con láser de diodo. Describimos la técnica de realización y se muestran los resultados postoperatorios a corto plazo.ResultadosTras un periodo de seguimiento no inferior a 12 meses se constató curación en el 95,24% aplicando una o dos sesiones y solamente en 4 casos se objetivó recidiva. Concluimos que la técnica de esclerosis endoluminal con láser de diodo de MVBF en el área orofacial se constituye como una nueva técnica de tratamiento, mínimamente invasiva, ambulatoria, y que permite la resolución de los casos sin tener que recurrir a cirugías más agresivas y con excelentes resultados funcionales y estéticos.AbstractBackgroundVascular anomalies are common processes that involve the head and neck region in more than 50% of the cases. Traditional treatment options such as surgery and chemical sclerosis have given way to modern less-invasive techniques, including Nd:YAG laser treatment. On the other hand, 980 nm laser diode has been successfully used for the endovenous sclerosis of varicose veins. Our proposal is the usage of diode laser (λ = 980 nm) to induce the sclerosis of low-flow venous malformations by intralesional photocoagulation, given this laser's ability to deliver the beam via a fiber optic cable.ObjectiveTo report our results in the treatment of orofacial low-flow venous malformations (LFVM) with diode laser endovenous sclerosis (DLES).Material and methods: The clinical records from 84 patients presenting with orofacial LFVM treated with DLES were collected. The technique used and short-term postoperative results were revised.ResultsAfter a follow-up period of at least 12 months after one or two DLES sessions, healing was observed in 95.24% of the cases. Only 4 cases showed relapse.ConclusionsThe DLES technique is a new therapeutic option for the treatment of orofacial LFVM, is minimally-invasive, allows an outpatient setting and achieves excellent functional and esthetic results avoiding more aggressive procedures

Caracterización de válvulas de admisión y expulsión de aire comerciales

El objetivo del trabajo es estudiar en detalle el comportamiento real de diferentes ventosas (válvulas de admisión y expulsión de aire). La primera parte del trabajo describe las diferentes técnicas experimentales de caracterización de ventosas. En la segunda parte se utiliza el banco de pruebas de válvulas de aire construido por Bermad CS en su fábrica de Evron, Israel, para realizar los ensayos de caracterización estática a diferentes ventosas comerciales. Finalmente se realiza un estudio comparativo del comportamiento de los diferentes modelos analizados, analizando los coeficientes más adecuados para la caracterización matemática de estos elementos