Métodos machine learning para la predicción de inclusiones no metálicas en alambres de acero para refuerzo de neumáticos

ABSTRACT: Non-metallic inclusions are unavoidably produced during steel casting resulting in lower mechanical strength and other detrimental effects. This study was aimed at developing a reliable Machine Learning algorithm to classify castings of steel for tire reinforcement depending on the number and properties of inclusions, experimentally determined. 855 observations were available for training, validation and testing the algorithms, obtained from the quality control of the steel. 140 parameters are monitored during fabrication, which are the features of the analysis; the output is 1 or 0 depending on whether the casting is rejected or not. The following algorithms have been employed: Logistic Regression, K-Nearest Neighbors, Support Vector Classifier (linear and RBF kernels), Random Forests, AdaBoost, Gradient Boosting and Artificial Neural Networks. The reduced value of the rejection rate implies that classification must be carried out on an imbalanced dataset. Resampling methods and specific scores for imbalanced datasets (Recall, Precision and AUC rather than Accuracy) were used. Random Forest was the most successful method providing an AUC in the test set of 0.85. No significant improvements were detected after resampling. The improvement derived from implementing this algorithm in the sampling procedure for quality control during steelmaking has been quantified. In this sense, it has been proved that this tool allows the samples with a higher probability of being rejected to be selected, thus improving the effectiveness of the quality control. In addition, the optimized Random Forest has enabled to identify the most important features, which have been satisfactorily interpreted on a metallurgical basis.RESUMEN: Las inclusiones no metálicas se producen inevitablemente durante la fabricación del acero, lo que resulta en una menor resistencia mecánica y otros efectos perjudiciales. El objetivo de este estudio fue desarrollar un algoritmo fiable para clasificar las coladas de acero de refuerzo de neumáticos en función del número y el tipo de las inclusiones, determinadas experimentalmente. Se dispuso de 855 observaciones para el entrenamiento, validación y test de los algoritmos, obtenidos a partir del control de calidad del acero. Durante la fabricación se controlan 140 parámetros, que son las características del análisis; el resultado es 1 ó 0 dependiendo de si la colada es rechazada o no. Se han empleado los siguientes algoritmos: Regresión Logística, Vecinos K-Cercanos, Clasificador de Vectores Soporte (kernels lineales y RBF), Bosques Aleatorios, AdaBoost, Gradient Boosting y Redes Neurales Artificiales. El bajo índice de rechazo implica que la clasificación debe llevarse a cabo en un set de datos desequilibrado. Se utilizaron métodos de remuestreo y métricas específicas para conjuntos de datos desequilibrados (Recall, Precision y AUC en lugar de Accuracy). Random Forest fue el algoritmo más exitoso que proporcionó un AUC en los datos de test de 0.83. No se detectaron mejoras significativas después del remuestreo. Se ha cuantificado la mejora derivada de la implementación de este algoritmo en el procedimiento de muestreo para el control de calidad durante la fabricación de acero. En este sentido, se ha comprobado que esta herramienta permite seleccionar las muestras con mayor probabilidad de ser rechazadas, mejorando así la eficacia del control de calidad. Además, el Random Forest optimizado ha permitido identificar las variables más importantes, que han sido interpretadas satisfactoriamente sobre una base metalúrgica.Máster en Ciencia de Dato

Analysis of notch effect in load bearing capacity, apparent fracture toughness and fracture micromechanisms of ferritic–pearlitic steels

This paper presents the analysis of the notch effect in two ferritc–pearlitic steels: S275JR and S355J2. The research is based on the development and analysis of an experimental programme composed of 336 CT specimens, combining 6 different notch radii, and testing temperatures from the lower shelf up to the upper shelf of the two materials. The notch effect is analysed through the evolution of both the load bearing capacity and the apparent fracture toughness, and also through the relation between these two variables and the failure micromechanisms. The results reveal a clear notch effect in both materials. In the case of the load bearing capacity, this notch effect has its maximum at lower shelf temperatures. The notch effect in the apparent fracture presents a maximum at the lower temperatures of the ductileto-brittle transition zone. Finally, the Scanning Electron Microscopy fractographies have justified the previous observations

Análisis del efecto entalla en la tenacidad aparente y en los micromecanismos de rotura del acero S275JR en condiciones de lower shelf

La resistencia a fractura de los materiales es generalmente mayor en condiciones entalladas que en condiciones fisuradas. En otras palabras, cuando el radio de entalla crece se produce igualmente un aumento de la tenacidad aparente a fractura, que es aquella observada en condiciones entalladas. Este artículo presenta un análisis del efecto entalla en el acero S275JR cuando opera a temperaturas pertenecientes al Lower Shelf del material, es decir, aquellas temperaturas en las cuales la fractura del material en condiciones fisuradas se produce por clivajes. Para ello se desarrolla un programa experimental en el cual se ensayan probetas CT a dos temperaturas diferentes pertenecientes al Lower Shelf del material (-90ºC y -120ºC), con radios de entalla que varían de 0 mm (fisuras) hasta 2.0 mm. Además se realiza un análisis por elementos finitos con el objetivo de validar las predicciones de tenacidad aparente proporcionadas por la Teoría de las Distancias Críticas. Los resultados muestran que dicha teoría proporciona predicciones ajustadas de la tenacidad aparente del material bajo las condiciones de ensayo contempladas en este trabajo. El trabajo se completa con el análisis de la evolución de los micromecanismos de fractura con el radio de entalla, observándose una relación directa entre tal evolución y las observaciones de tenacidad aparente a fractura

Structural integrity assessment of a nuclear vessel through ASME and master curve approaches using irradiation embrittlement predictions

ABSTRACT: The assessment of the structural integrity of nuclear vessels is based on a series of procedures developed in the 1970s and 1980s. On one hand, curves that, according to the American Society of Mechanical Engineers code, describe the relationship between steel toughness and temperature in the ductile-to-brittle transition region, based on the reference temperature concept RTNDT, were adopted in 1972. On the other hand, the material embrittlement derived from the exposure of steel to neutron irradiation is determined through the model included in “Regulatory Guide 1.99 Rev. 2,” published in 1988. Since then, there have been enormous advances in this field. For example, the Master Curve, based on the reference temperature T0, describes the relationship between toughness and temperature in the transition zone more realistically and with much more robust microstructural and mechanical foundations and uses the elastic-plastic fracture toughness KJc. Moreover, improved models have been developed to estimate the embrittlement of steel subjected to neutron irradiation, such as ASTM E900, Standard Guide for Predicting Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials. This study is aimed at comparing the results obtained using traditional procedures to the improved alternatives developed later. For this purpose, the behavior of the steel of a nuclear vessel that is currently under construction has been experimentally characterized through RTNDT and T0 parameters. In addition, the material embrittlement has been quantified using “Regulatory Guide 1.99 Rev. 2” and ASTM E900. These experimental results have been transferred to the assessment of the structural integrity of the vessel to determine the pressure-temperature limit curves and size of the maximum admissible defect as a function of the operation time of the plant. The results have allowed the implicit overconservatism present in the traditional procedures to be quantified.This project was carried out with the financial support of Sociedad para el Desarrollo Regional de Cantabria (SODERCAN) and Equipos Nucleares S.A. (ENSA), to whom the authors would like to express their gratitude

Shell Technology, Rock Art, and the Role of Marine Resources during the Upper Paleolithic

During the Upper Paleolithic, marine resources have traditionally been considered to be low-efficiency resources. However, in recent years, new data have emerged to demonstrate that their importance for human utilization was probably greater than previously thought. The assessment of their value has generally been from the perspective of their nutritional or ornamental value, not from the technological potential that these resources might have. A use-wear analysis of shells from the Gravettian levels of Fuente del Salín, a cave in northern Spain, has documented their use for a diverse range of production activities, most notably the processing of the red pigments used in artistic representations on the cave walls, as well as for tanning hide. This technological use of shells demonstrates that marine resources were of greater importance to the hunters and gatherers of the Upper Paleolithic and that their utility was more diverse than previously understood.This research was funded by the University of Cantabria through pre- and postdoctoral contract to David Cuenca-Solana and Alejandro Garcı´a-Moreno. Igor Gutierrez-Zugasti is currently funded by the Newton International Fellowships scheme. Parts of the analyses that support this research have been carried out as part of the project Human Response to Global Climate Change in a Littoral Zone: the Case of the Transition to the Holocene on the Cantabrian Coast (10,000–5,000 cal B.C.) (HAR2010-22115-C02-01), funded by the Spanish Ministry of Science and Innovation

Linking land cover changes in the subalpine and montane belts to changes in a torrential river.

Channel cbanges are the consequence of cbanges in sediment yield from the slopes and in the connectivity between slopes and channels bccause of distinct land use and climate inJpacts. In Ibis study, we investigated the characteristics and evolution of a short reach in the headwater of the !juez River, central-soutbem Pyrenees. Assessment of a series of sedimentar)' and geomorphic structures confirtned major cbanges to the valley boUom, mainly related to changes in the intensity of human activity. 'The oldest sedimentar)' structure is a terrace leve! located 3 10 4 m above the current alluvial plain. General deforestation, overgrazing and recwring tires in the montane belt ( 1100-1600 m a.sJ.) have led 10 increased soil erosioo and connectivity, and to tbe triggering of debris llows thal have been deposited on the fluvial tmace. Woody fragments from within the debris llows were dated using acceleraror mass spectrOmetry '"e radiocaroon tcchniques (AMS), yielding ages between 1 00 and 115 cal years BP, whicb coincides with tbe period of maximum deforestalion and human density in the Pyrenees. Depopulation and fannland abaodonment since tbe beginning of tbe 2001 oenrury has resulled in generalliJcod natural and artificial reforestation, a shrinkage of the eroded arcas aod a decline in connectivi¡y bdween slopes and the channel. 1be rnost impor1an1 consequence has been cbannel incision and oarrowing, and the development of a sedimed annour !ayer. Active sedimenl b8llSpOI1 is continui.Qg, although there has been a decrease in sed.iment yield from the slopes. Copyright O 2014 John Wiley & Soos, Ltd

INTERNET DE LAS COSAS (IoT), UNA ALTERNATIVA PARA EL CUIDADO DEL AGUA (INTERNET OF THINGS (IoT), AN ALTERNATIVE FOR THE CARE OF WATER)

ResumenDesde que Arquímedes inventó su tornillo para trasladar el agua cuesta arriba y los romanos construyeron sus acueductos, el ser humano ha intentado manipular el recurso más apreciado de la tierra mediante el uso de la tecnología. Muchos han soñado con hacer que los desiertos florezcan. Ahora, con la población mundial superando los siete mil millones y la demanda de agua en niveles sin precedentes, las nuevas tecnologías están ayudando a hacer uso más inteligente de este recurso natural esencial para la vida. En la producción agrícola, el riego es fundamental para una cosecha exitosa, pues la aplicación de agua durante el desarrollo del cultivo influye en su rendimiento y calidad de los frutos. Los vegetales están compuestos entre un 80 y 95% de agua. Por eso son tan susceptibles a retrasar su madurez y reducir su rendimiento cuando el daño por falta de agua ocurre al principio de su desarrollo o afectar su calidad cuando padecen estrés hídrico en las últimas etapas de desarrollo. Los métodos tradicionales empleados en la agricultura de precisión, generan grandes pérdidas para los agricultores. En el presente artículo se describe el diseño, elaboración e implementación de un sistema de riego empleando hardware y software libre, sensores, actuadores, telefonía móvil y servidores web, con el fin de crear un ambiente apropiado para que el Internet de las Cosas (IoT) y la Agricultura de Precisión ofrezcan al usuario una plataforma amigable para el monitoreo y control del riego en un invernadero inteligente.Palabra(s) Clave: Arduino, Agricultura de precisión, Internet de las cosas, Sensores. AbstractSince Archimedes invented his screw to move the water uphill and the Romans built their aqueducts, the human being has tried to manipulate the most appreciated resource on earth through the use of technology. Many have dreamed of making deserts flourish. Now, with the world population exceeding seven billion and the demand for water at unprecedented levels, new technologies are helping to make smarter use of this essential natural resource for life. In the agricultural production, the irrigation is fundamental for a successful harvest, because the application of water during the development of the crop influences in his performance and quality of the fruit. The vegetables are composed between 80 and 95% of water. That is why they are so susceptible to delaying their maturity and reducing their yield when damage due to lack of water occurs at the beginning of their development or affect their quality when they suffer water stress in the later stages of development. The traditional methods used in precision agriculture generate large losses for farmers. This article describes the design, development and implementation of an irrigation system using hardware and free software, sensors, actuators, mobile telephony and web servers, in order to create an appropriate environment for the Internet of Things (IoT) and Precision Agriculture offer the user a friendly platform for the monitoring and control of irrigation in a smart greenhouse.Keywords: Arduino, Internet of Things, Precision Farming, Sensors

SISTEMA PARA EL MONITOREO REMOTO DE COLONIAS DE ABEJAS MELÍFERAS

ResumenLas abejas son muy importantes para el equilibrio del ecosistema y sobre todo, para la subsistencia de muchos cultivos, debido a su capacidad para polinizar las flores. Actualmente, las poblaciones de abejas melíferas están disminuyendo debido al desorden del colapso de la colonia, las razones no se conocen completamente, el monitoreo remoto de la colmena es esencial para obtener toda la información posible sobre las condiciones ambientales que la rodean. Por otra parte, es importante llevar a cabo la recolección de información utilizando las nuevas tecnologías para no perturbar las condiciones de trabajo de las abejas y obtener datos más confiables. Se ha instalado una red de sensores que cumplen con este requisito, a través de un sistema de monitoreo remoto, basado en un modelo jerárquico de dos niveles formado por el nodo inalámbrico y un servidor local. El sistema para el monitoreo de variables físicas dentro y fuera de una colmena es completamente escalable, en cuanto a sensores y colmenas, logrando con ello monitorear diferentes puntos dentro y fuera de ella, almacenando datos de temperatura y humedad relativa. De manera que los investigadores y apicultores pueden acceder al servidor de datos para averiguar la condición de sus colmenas en tiempo real.Palabra(s) Clave: Apicultura de precisión; Monitoreo de colonias de abejas; Sensor inalámbrico. SYSTEM FOR REMOTE MONITORING OF HONEY BEE COLONIESAbstractBees are very important for the balance of the ecosystem and especially for the subsistence of many crops, due to their ability to pollinate flowers. At present, honey bee populations are declining due to collapse disorder of the colony, reasons are not fully understood, remote monitoring of the hive is essential to obtain all possible information about the surrounding environmental conditions. On the other hand, it is important to carry out the collection of information using the new technologies so as not to disturb the working conditions of the bees and obtain more reliable data. We have installed a network of sensors that meet this requirement, through a remote monitoring system, based on a hierarchical two-level model formed by the wireless node and a local server. The monitoring system is a low-cost, fully scalable, number and types of sensors, number of hives and their geographical distribution. Unlike other systems monitoring at a single point in a hive, the system we present monitors and stores the temperature and relative humidity of the hive at three different points. Researchers and beekeepers can access the data server to find out the condition of their hives in real time.Keywords: Monitoring of bee colonies, Precision beekeeping, Wireless sensor

SISTEMA PARA EL MONITOREO DE VARIABLES FISICAS DENTRO DE UNA COLMENA

ResumenEste documento presenta el desarrollo de un sistema para el monitoreo de variables físicas al interior de una colmena artificial, cuya finalidad es obtener información sobre el estado general la misma, enviarla a un servidor web donde será almacenada. Existen ciertas variables físicas dentro de la colmena y eventos sobre ésta que afectan la salud y productividad de las abejas. En este documento se muestra, la forma de obtener y procesar de forma automática las variables dentro y fuera de la colmena para ser presentada al usuario final, sobre una pantalla de cristal líquido y un entorno gráfico adecuado para su interpretación. El sistema de monitoreo fue ensamblado y montado sobre una colmena apícola artificial en laboratorio, para realizar las pruebas necesarias, fueron establecidas ciertas condiciones controladas con el fin de evaluar la efectividad del sistema. Las condiciones de temperatura y humedad cerca de los sensores fueron modificadas. También fue simulado el ingreso y partida de abejas a través de los orificios dispuestos en la estructura. Los sistemas desarrollados para la apicultura bajo plataformas tecnológicas embebidas son herramientas eficaces y altamente robustas para realizar tareas específicas de medición de variables físicas y eventos que afectan las colmenas, manejo de información y comunicación para sistemas de monitoreo en campo y remoto a un bajo costo. El Sistema para el monitoreo de variables físicas dentro de la colmena tiene una interfaz fácil de entender y manejar por los productores en campo.Palabra(s) Clave: Arduino, Colmena, Dispositivo de almacenamiento, Sensor, Software. SYSTEM FOR THE MONITORING OF PHYSICAL VARIABLES WITHIN A HIVEAbstractThis document presents the development of a system for the monitoring of physical variables inside an artificial hive, whose purpose is to obtain information about the general state of the hive, send it to a web server where it will be stored in a database. There are certain physical variables within the hive and events on it that affect the health and productivity of bees; the ranges that guarantee the health and stability of the hive for these physical variables were identified. This document shows how this information is obtained and processed to be presented to the end user, on a liquid crystal display and a graphical environment suitable for interpretation.Keywords: Arduino, Hive, Sensor, Software, Storage device

Mid and late Holocene forest fires and deforestation in the subalpine belt of the Iberian range, northern Spain

26 Pags.- 6 Figs.- 2 Tabls. The definitive version is available at: http://link.springer.com/journal/11629The conversion of subalpine forests into grasslands for pastoral use is a well-known phenomenon, although for most mountain areas the timing of deforestation has not been determined. The presence of charcoal fragments in soil profiles affected by shallow landsliding enabled us to date the occurrence of fires and the periods of conversion of subalpine forest into grasslands in the Urbión Mountains, Iberian Range, Spain. We found that the treeline in the highest parts of the northwestern massifs of the Iberian Range (the Urbión, Demanda, Neila, and Cebollera massifs) is currently between 1500 and 1600 m a.s.l., probably because of pastoral use of the subalpine belt, whereas in the past it would have reached almost the highest divides (at approximately 2100–2200 m a.s.l.). The radiocarbon dates obtained indicate that the transformation of the subalpine belt occurred during the Late Neolithic, Chalcolithic, Bronze Age, Iron Age, and Middle Ages. Forest clearing was probably moderate during fires prior to the Middle Ages, as the small size of the sheep herds and the local character of the markets only required small clearings, and therefore more limited fires. Thus, it is likely that the forest recovered burnt areas in a few decades; this suggests the management of the forest and grasslands following a slash-and-burn system. During the Middle and Modern Ages deforestation and grassland expansion affected most of the subalpine belt and coincided with the increasing prevalence of transhumance, as occurred in other mountains in the Iberian Peninsula (particularly the Pyrenees). Although the occurrence of shallow landslides following deforestation between the Neolithic and the Roman Period cannot be ruled out, the most extensive shallow landsliding processes would have occurred from the Middle Ages until recent times.Support for this research was provided by the projects INDICA (CGL2011- 27753-C02-01 and -02) and DINAMO2 (CGL2012-33063), funded by the Spanish Ministry of Economy and Competitiveness.Peer reviewe