Modelado de la combustión en motores Diésel: revisión del estado del arte

ResumenEl estudio del proceso de combustión en motores Diésel ha sido, durante años, un tema de gran interés debido principalmente a la creciente necesidad de mejorar el rendimiento de los motores, reducir el consumo de combustible y reducir la emisión de contaminantes. Los estudios experimentales presentan la desventaja de requerir grandes recursos económicos y tiempo en su realización, razón por la cual se utilizan modelos computacionales que permiten estudiar el proceso de combustión de una forma más económica y práctica. En este artículo se presenta una revisión de varios de los modelos de combustión en motores Diésel más  relevantes, desarrollados a nivel nacional e  internacional, con el fn de dar al lector una visión de la evolución y el estado actual de este tipo de modelos.Palabras clave: modelado de la combustión, motores diesel, modelos termodinámicos, modelos multidimensionales.  Modelling of combustion in Diesel engines: a review of the state of the artAbstractThe study of the combustion process in Diesel engines has been for years a subject of great interest mainly due to the increasing need to improve engine performance, reduce fuel consumption and reduce the pollutant emissions. Experimental studies have the disadvantage of require enormous efforts, money and time, that is the reason why computer models are used to study the combustion process in a more economical and practical way. This article presents a review of the most relevant Diesel engine combustion models developed nationally and internationally, to give the reader an insight of the evolution and current status of such modelsKeywords: combustion modeling, diesel engines, thermodynamics models, multidimensional models

Analytical and experimental performance study of diesel engines powered with hydrotreated Bio-Oil

Due to the serious problems encountered because of the extensive use of first-generation biofuels, second generation biofuels are presented as one of the best possible alternatives conventional fuels from oil. This paper presents a theoretical study of the performance of diesel engines fueled with hydrotreated bio-oil from lignocellulosic biomass, which is a second generation biofuel. For this, a thermodynamic zero-dimensional combustion model simulation was carried out, which predicts the performance parameters of the engine. This model was validated against experimental data of two diesel engines fueled with diesel-biodiesel  and  diesel/hydrotreated  bio-oil  blends, and  a  good  correlation between simulated and experimental data was observed, with average relative errors in pressure peak values of 0.5 and 1%, respectively. The results show that hydrotreated bio-oil in small proportions could become a partial substitute for conventional diesel fuel.Debido a los graves problemas presentados a causa del amplio uso de biocombustibles de primera generación, los biocombustibles de segunda generación se presentan como una posible mejor alternativa para la sustitución de los combustibles convencionales provenientes del petróleo. En el presente artículo se presenta un estudio del desempeño de motores diésel alimentados con bio-oil hidrotratado proveniente de biomasa lignocelulósica, el cual es un biocombustible de segunda generación; para esto se desarrolló un modelo termodinámico cero-dimensional de la combustión que predice los parámetros de desempeño del motor. Este modelo fue validado contra datos experimentales de presión en cámara de dos motores diésel alimentados con mezclas diésel/biodiésel y diésel/bio-oil hidrotratado, observándose una buena correlación entre los datos simulados y experimentales, con errores relativos promedio en los valores pico de presión de 0,5 y 1 % respectivamente. Los resultados muestran que el bio-oil hidrotratado, al utilizarse en pequeñas proporciones, puede convertirse en un sustituto parcial del combustible diésel convencional. &nbsp

Caracterización estructural, térmica y morfológica de Crescentia cujete (totumo) con potencial uso como polímero biodegradable

Actualmente, se reconoce que los plásticos derivados de productos petroquímicos son uno de los mayores problemas sociales y ambientales, debido al uso excesivo y a la dificultad de su descomposición, lo que ha aumentado la preocupación por encontrar alternativas a estos materiales. De esta forma, este trabajo se centra en la caracterización por medio de DRX, FRX FTIR, DSC, TGA y análisis cualitativo de biodegradabilidad del fruto de Crescentia cujete (totumo), a fin de establecer bases para ser considerado una alternativa de uso, como polímero biodegradable. Los resultados de la caracterización estructural evidenciaron que se trata de un material semicristalino, compuesto, principalmente, de celulosa tipo I, con una cristalinidad del 29 %. Se determinó que la estabilidad térmica de este material alcanza los 175 °C, con la pérdida de humedad, siendo la única observación hasta esta temperatura. Se confirmó la presencia de hemicelulosa y celulosa a temperaturas superiores y su posterior descomposición. El estudio de biodegradabilidad indicó la presencia de un ataque microbiano a las 72 horas de monitoreo, evidenciado por la aparición de un hongo en la superficie del material, lo que causó cambios en la emisión de dióxido de carbono y monóxido de carbono. Después de 200 horas se observó una disminución del volumen del hongo, lo que sugiere que este se propagó al interior del material, dando origen puntos negros de descomposición en la superficie de las muestras. Así, el totumo se podría considerar como una alternativa de material lignocelulósico, para la preparación de materiales poliméricos biodegradables

Analytical and experimental performance study of diesel engines powered with hydrotreated Bio-Oil

Due to the serious problems encountered because of the extensive use of first-generation biofuels, second generation biofuels are presented as one of the best possible alternatives conventional fuels from oil. This paper presents a theoretical study of the performance of diesel engines fueled with hydrotreated bio-oil from lignocellulosic biomass, which is a second generation biofuel. For this, a thermodynamic zero-dimensional combustion model simulation was carried out, which predicts the performance parameters of the engine. This model was validated against experimental data of two diesel engines fueled with diesel-biodiesel  and  diesel/hydrotreated  bio-oil  blends, and  a  good  correlation between simulated and experimental data was observed, with average relative errors in pressure peak values of 0.5 and 1%, respectively. The results show that hydrotreated bio-oil in small proportions could become a partial substitute for conventional diesel fuel.Debido a los graves problemas presentados a causa del amplio uso de biocombustibles de primera generación, los biocombustibles de segunda generación se presentan como una posible mejor alternativa para la sustitución de los combustibles convencionales provenientes del petróleo. En el presente artículo se presenta un estudio del desempeño de motores diésel alimentados con bio-oil hidrotratado proveniente de biomasa lignocelulósica, el cual es un biocombustible de segunda generación; para esto se desarrolló un modelo termodinámico cero-dimensional de la combustión que predice los parámetros de desempeño del motor. Este modelo fue validado contra datos experimentales de presión en cámara de dos motores diésel alimentados con mezclas diésel/biodiésel y diésel/bio-oil hidrotratado, observándose una buena correlación entre los datos simulados y experimentales, con errores relativos promedio en los valores pico de presión de 0,5 y 1 % respectivamente. Los resultados muestran que el bio-oil hidrotratado, al utilizarse en pequeñas proporciones, puede convertirse en un sustituto parcial del combustible diésel convencional. &nbsp

Obras y artistas portugueses en la Tierra de Sevilla entre los siglos XVI al XVIII

La actual comarca de la Sierra de Huelva, territorio limítrofe con el alto Alentejo portugués, fue, desde la Baja Edad Media, un espacio de prolijos intercambios comerciales, de trasvases de población y, en particular en el ámbito de las artes, de permuta de obras y artistas entre los dos países. Las poblaciones a ambos lados de la frontera muestran signos común de identidad, de manifiesto tanto a nivel de arte popular como de arte culto, principalmente en los campos de la arquitectura y la escultura. Este artículo recopila todos los ejemplos, hasta hoy conocidos, de la actividad de artistas portugueses en la comarca, unos publicados desde hace años junto a otros inéditos.The current region of the Huelva Mountains, a territory bordering the Portuguese Alentejo High, was, since the Late Middle Ages, a space of prolific commercial exchanges, population transfers and, in particular in the field of the arts, a swap works and artists between the two countries. Populations on both sides of the border show common signs of identity, manifested both at the level of popular art and cult art, mainly in the fields of architecture and sculpture. This article collects all the examples, until today known, of the activity of Portuguese artists in the region, some published since some years ago with other unpublished ones

Executive summary: Diagnosis and Treatment of Catheter-Related Bloodstream Infection: Clinical Guidelines of the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC) and the Spanish Society of Intensive Care Medicine and Coronary Units (SEMICYUC)

Catheter-related bloodstream infections (CRBSI) constitute an important cause of hospital-acquired infection associated with morbidity, mortality, and cost. The aim of these guidelines is to provide updated recommendations for the diagnosis and management of CRBSI in adults. Prevention of CRBSI is excluded. Experts in the field were designated by the two participating Societies (Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica and the Sociedad Española de Medicina Intensiva, Crítica y Unidades Coronarias). Short-term peripheral venous catheters, non-tunneled and long-term central venous catheters, tunneled catheters and hemodialysis catheters are covered by these guidelines. The panel identified 39 key topics that were formulated in accordance with the PICO format. The strength of the recommendations and quality of the evidence were graded in accordance with ESCMID guidelines. Recommendations are made for the diagnosis of CRBSI with and without catheter removal and of tunnel infection. The document establishes the clinical situations in which a conservative diagnosis of CRBSI (diagnosis without catheter removal) is feasible. Recommendations are also made regarding empirical therapy, pathogen-specific treatment (coagulase-negative staphylococci, Sthaphylococcus aureus, Enterococcus spp, Gram-negative bacilli, and Candida spp), antibiotic lock therapy, diagnosis and management of suppurative thrombophlebitis and local complications

Selection for growth is associated in gilthead sea bream (Sparus aurata) with diet flexibility, changes in growth patterns and higher intestine plasticity

Farmed gilthead sea bream (Sparus aurata) is able to grow efficiently with new feed formulations based on plant ingredients. Here, two experimental diets with standard and high inclusion levels of plant ingredients were formulated to assess the suited use of plant-based diets in fish with different growth genetic backgrounds. To pursue this issue, a long-term feeding trial (12-months) was conducted with fish (17 g initial body weight) of 16 families coming from the broodstock of PROGENSA project, that were grown communally in the IATS-CSIC experimental facilities. All fish in the study (2545) were PIT-tagged, and their pedigree was re-constructed with 96% success by using a SMsa1 multiplex of 11 microsatellites, which revealed the main parents contributions of 5 females and 6 males. Each diet was randomly assigned to replicate 3000 L tanks, gathering each replicate a similar family composition through all the feeding trial. Data on growth performance highlighted a strong ge- netic effect on growth trajectories, associated with enhanced growth during winter in fish selected for faster growth. No main dietary effects were found on growth rates or condition factor, and regression-correlation analyses of growth rates across families on both diets suggest that genome by diet interaction was weak, while genetic variation accounted for most of the growth phenotypic variation. Hepatosomatic index (HSI) and me- senteric fat index (MSI) of five families, covering the growth variability of the population, were regulated nu- tritionally and genetically, but without statistically significant genome by diet interactions. Fish from faster growing families showed shorter intestines after being fed the control diet, but this phenotype was masked by the enriched plant-based diet. Collectively, the results demonstrate that selection for faster growth is associated in gilthead sea bream with different growth trajectories and a high diet flexibility and intestine plasticity.Versión del editor2,04

HESML: A scalable ontology-based semantic similarity measures library with a set of reproducible experiments and a replication dataset

This work is a detailed companion reproducibility paper of the methods and experiments proposed by Lastra-Díaz and García-Serrano in (2015, 2016) [56–58], which introduces the following contributions: (1) a new and efficient representation model for taxonomies, called PosetHERep, which is an adaptation of the half-edge data structure commonly used to represent discrete manifolds and planar graphs; (2) a new Java software library called the Half-Edge Semantic Measures Library (HESML) based on PosetHERep, which implements most ontology-based semantic similarity measures and Information Content (IC) models reported in the literature; (3) a set of reproducible experiments on word similarity based on HESML and ReproZip with the aim of exactly reproducing the experimental surveys in the three aforementioned works; (4) a replication framework and dataset, called WNSimRep v1, whose aim is to assist the exact replication of most methods reported in the literature; and finally, (5) a set of scalability and performance benchmarks for semantic measures libraries. PosetHERep and HESML are motivated by several drawbacks in the current semantic measures libraries, especially the performance and scalability, as well as the evaluation of new methods and the replication of most previous methods. The reproducible experiments introduced herein are encouraged by the lack of a set of large, self-contained and easily reproducible experiments with the aim of replicating and confirming previously reported results. Likewise, the WNSimRep v1 dataset is motivated by the discovery of several contradictory results and difficulties in reproducing previously reported methods and experiments. PosetHERep proposes a memory-efficient representation for taxonomies which linearly scales with the size of the taxonomy and provides an efficient implementation of most taxonomy-based algorithms used by the semantic measures and IC models, whilst HESML provides an open framework to aid research into the area by providing a simpler and more efficient software architecture than the current software libraries. Finally, we prove the outperformance of HESML on the state-of-the-art libraries, as well as the possibility of significantly improving their performance and scalability without caching using PosetHERep

Informe preliminar. Propuesta de protección para la sierra de la mosca. Cáceres - Sierra de Fuentes

Presentamos este INFORME PRELIMINAR con el objetivo de impulsar una figura de protección para LA SIERRA DE LA MOSCA de Cáceres, para su justa valoración como espacio natural bien conservado, como forma de mantener a los ciudadanos cacereños concienciados con la importancia de sus recursos naturales y culturales, complementada con una serie de propuestas de usos y promoción social que la hagan más atractiva y eviten la amenaza del progresivo deterioro ecológico al que se encuentra hoy sometida esta zona periurbana.We present this PRELIMINARY REPORT with the aim of promoting a protection figure for LA SIERRA DE LA MOSCA of Cáceres, for its fair valuation as a well-conserved natural space, as a way of keeping the citizens of Cáceres aware of the importance of its natural and cultural resources, complemented with a series of proposals of uses and social promotion that make it more attractive and avoid the threat of the progressive ecological deterioration to which this periurban area is subjected today

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected