A novel machine learning‐based methodology for tool wear prediction using acoustic emission signals

There is an increasing trend in the industry of knowing in real-time the condition of their assets. In particular, tool wear is a critical aspect, which requires real-time monitoring to reduce costs and scrap in machining processes. Traditionally, for the purpose of predicting tool wear conditions in machining, mathematical models have been developed to extract the information from the signal of sensors attached to the machines. To reduce the complexity of developing physical models, where an in-depth knowledge of the system being modelled is required, the current trend is to use machine-learning (ML) models based on data from the tool wear. The acoustic emission (AE) technique has been widely used to capture data from and understand the real-time condition of industrial assets such as cutting tools. However, AE signal interpretation and processing is rather complex. One of the most common features extracted from AE signals to predict the tool wear is the counts parameter, defined as the number of times that the amplitude of the signal exceeds a predefined threshold. A recurrent problem of this feature is to define the adequate threshold to obtain consistent wear prediction. Additionally, AE signal bandwidth is rather wide, and the selection of the optimum frequencies band for feature extraction has been pointed out as critical and complex by many authors. To overcome these problems, this paper proposes a methodology that applies multi-threshold count feature extraction at multiresolution level using wavelet packet transform, which extracts a redundant and non-optimal feature map from the AE signal. Next, recursive feature elimination is performed to reduce and optimize the vast number of predicting features generated in the previous step, and random forests regression provides the estimated tool wear. The methodology presented was tested using data captured when turning 19NiMoCr6 steel under pre-established cutting conditions. The results obtained were compared with several ML algorithms such as k-nearest neighbors, support vector machines, artificial neural networks and decision trees. Experimental results show that the proposed method can reduce the predicted root mean squared error by 36.53%

Understanding Switched-Flux Machines: A MMF-Permeance Model and Magnetic Equivalent Circuit Approach

Due to their particular structure, switched-flux permanent magnet machines have become a very interesting alternative for many applications. This is why some recent studies have been focused in the understanding of the operating mechanism of these machines via the MMF-permeance modelling. However, the models that can be found in the literature make some simplifications that reduce their accuracy when predicting the performance of switched-flux machines. For example, the models that can be found in the literature are commonly not precise enough for machines with a wide slot, because the influence of the modulator of the primary side of the machine is neglected. In this article, a precise analytical model is developed for a 6/13 C-Core switched-flux machine via a combination of a magnetic equivalent circuit and a MMF-permeance model. The model is based on the magnetic field modulation principle. The analytical model is used to explain the flux focusing effect and the force generation mechanism of switched-flux machines. A new concept of PM field harmonic efficiency ratio is used to identify the most efficient PM field harmonics of 2 switched-flux machines. The precision of the model is validated via 2D and 3D Finite Element Method simulations, and experimental measurements that were obtained with a linear machine prototype. The results show that the model can predict the performance of switched-flux machines with a high accuracy level

Registro fósil precuaternario de tetrápodos en los Pirineos occidentales

El estudio de los niveles fosilíferos continentales y marinos del Cretácico Superior y del Terciario de la Región Vasco-Cantabrica (Sinclinorio Subcantábrico) y cuencas surpirenaicas adyacentes (Cuenca de Pamplona, Sector Noroccidental de la Depresión del Ebro) ha puesto de manifiesto su potencial paleontológico en restos fósiles de vertebrados. Algunos de estos yacimientos son de gran relevancia en el Cretácico final de Europa, incluyendo nuevas especies de tortugas, escamosos, cocodrilos, dinosaurios y mamíferos. En la misma cantera del yacimiento alavés de Zambrana, compuesta principalmente por reptiles y mamíferos, es de gran interés paleontológico y contribuye a un mejor conocimiento de las faunas del Eoceno superior de la Península Ibérica. En Zambrana se ha reconocido hasta la fecha varias nuevas especies de perisodáctilos ecuoideos. En el Neogeno, se han descubierto nuevas localidades del Mioceno (Rambliense, Aragoniense) en las Bardenas Reales de Navarra y otras áreas colindantes de la Cuenca del Ebro, que han proporcionado restos de anfibios, escamosos, tortugas, cocodrilos, aves y varios grupos de mamíferos. Por otro lado, una notable variedad de icnofacies de aves y mamíferos ha sido hallada en diferentes afloramientos de los potentes depósitos marinos litorales (Eoceno superior) y continentales (Oligoceno-Mioceno inferior) de la Alta Navarra

Dinosauro teropodoen hortzak eta dietan duten islapena

Dinosauro teropodoak nahiko urriak dira erregistro fosilean eta, askotan, aurkitutako fosil bakarrak hortz isolatuak dira. Teropodoen hortzekin, ordea, azterketa paleontologiko anitz egin daitezke, metodologia kualitatibo eta kuan-titatibo mota desberdinak erabiliz. Hortzetatik abiatuz, teropodoen biosistematika burutu eta talde honen erregistro fosila eta paleobiodibertsitatea ezagutu daitezke, baita hainbat diziplina paleobiologikoren azterketa egin ere, hala nola paleoekologia (iraganeko bizidunek beren artean eta ingurunearekin duten erlazioaren azterketa) eta paleobiogeografia (iraganeko bizidu-nen banaketa biogeografikoaren azterketa). Azterketa paleoekologiko bat dinosauro hauen dieta ezagutzea litzateke. Tero-podoen lehendabiziko ordezkariek hortz zifodontoak (laban itxurakoak) zituzten; hortz hauek aproposak dira haragia eba-kitzeko. Hortz pakidontoek (banana gisakoak) zifodontoek baino erresistentzia handiagoa erakusten dute. Kate trofikoaren goialdean dauden teropodo haragijaleetan agertzen dira eta hezurrak txikitzea eta haragian ebakidura zabalak egitea ahalbi-detzen zieten dinosauroei. Hortzeria konidontoa (hortz lateral konikodun hortzeria) zulatzeko eta harrapakinak eusteko da egokia, eta dinosauro iktiofago, herbiboro eta intsektiboro batzuetan garatu zen. Hortzeria folidontodun teropodoei, hau da, hosto itxurako hortzak dituztenei, dieta mota ezberdinak esleitu zaizkie; hala nola haragijalea, intsektiboroa, omniboroa edo herbiboroa. Nahiz eta dinosauro teropodoek hortzeria mota ezberdinak izan, batzuek hortzen galera erakusten dute. Edentu-lismoa (hortzen galera partziala edo osoa) teropodo talde ezberdinetan gertatu zen independenteki. Edentulismoaren zerga-tia jorratzen duten hipotesi asko proposatu diren arren, argi dago hortz gabeko moko batek funtzio asko bete ditzakeela, die-tan besteak beste, eta, beraz, berrikuntza ebolutibo garrantzitsua izan zela dinosauro teropodo ez-hegaztietan eta hegaztietan. Izan ere, gaur egun, hortz gabeko hegaztiak dira bizirik dirauten dinosauro bakarrak.; Isolated theropod teeth are the most common elements of this dinosaur clade found in the fossil record. This has led to the development of different qualitative, quantitative and phylogenetic methodologies in the study of isolated theropod teeth. This research has applications in systematic palaeontology, palaeobiodiversity, palaeoecology, and palaeo-biogeography. Moreover, the theropod teeth can inform us about the diet of these dinosaurs. Ziphodont (blade-like) teeth are suitable for cutting flesh; this dentition type is the ancestral theropod condition. Pachydont (banana-like) teeth show greater strength than ziphodont teeth. Pachydonty is present in carnivorous theropods that are at the top of the food chain and are able to crush bones and make wide incisions in the flesh. Conidont (conical) teeth are suitable for drilling and hold-ing prey. Conidonty developed in theropods with ichthyophagous, herbivorous, and insectivorous diets. Folidonty (leaf-shaped lateral crowns) occurs in theropods consuming distinct types of food, such as carnivores, insectivores, omnivores, or herbivores, including species of different clades. Edentulism has developed independently in several different theropod clades. Many hypotheses have been proposed to address the origin of edentulism in theropods; it is undeniable that a tooth-less beak can perform many functions and has therefore been an important evolutionary innovation in non-avian theropods and birds. In fact, toothless birds are the only theropods left alive today

The evolutionary ecology of the endemic European Eocene Plagiolophus (Mammalia: Perissodactyla)

The climatic cooling that began in the late middle Eocene and culminated in the Eocene-Oligocene transition meant major changes in Palaeotheriidae (Perissodactyla, Mammalia) biodiversity in Europe and could have caused the appearance of new dietary strategies. This work is the first to study the spatiotemporal response of one palaeotheriid genus (Plagiolophus) to the Eocene environmental and ecological changes using three dietary proxies: hypsodonty, mesowear and dental microwear texture analysis (DMTA). DMTA is applied for the first time to palaeotheriids. The high diversity and wide chrono-spatial distribution of Plagiolophus make it possible to evaluate spatiotemporal environmental variations, including palaeodiet. We study five Plagiolophus samples from late middle Eocene to early Oligocene from western Iberia to central Europe in order to (1) infer lifetime palaeodiet; (2) infer short-term palaeodiet; and (3) test temporal and spatial trends. All samples present an exclusion of abrasive foodstuff given low hypsodonty index; dominance of browsing given the low mesowear score; and browsing of tough foliage and exclusion of hard items in their diet given DMTA information. These factors point to Plagiolophus as a highly selective feeder that fed on plants with the same features irrespective of chronology or location: tough foliage (leaves from monocots or dicots) avoiding lignified or hard materials, without seasonal variations.Financial support was provided by the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (projects CGL2017–85038-P and PGC2018–093925-B-C33), the Basque Country Government (research groups of the Gobierno Vasco/Eusko Jaurlaritza IT1004–16 and IT418–19) and the UPV/EHU (PPG17/04). LPG received a pre-doctoral grant from the UPV/EHU (PIF16/190). AGO is supported by a Ramon y Cajal fellowship (RYC-2017-22558). GM is funded by ANR TRIDENT (ANR-13-JSV7–0008-01, PI: GM)

Mechanical and electrical properties of additively manufactured copper

Additive Manufacturing (AM) has become the new paradigm of design and production strategies. While structural and functional materials are the most implemented ones, it is also possible to manufacture parts using precious metals, being copper one of the most interesting. Among AM technologies, the novel Atomic Diffusion Additive Manufacturing (ADAM) hasrecently included this material between available ones. ADAM is free from thermal and energetic issues caused by high reflectivity and conductivity of copper which other AM encounter. Therefore, it could be a great alternative to manufacture pure copper. In this work ADAM was used to fabricate pure copper specimens in order to measure electrical and mechanical properties. The influence of a machining post processes in strength and ductility is also discussed. Results are compared with wrought C1 1000 copper and published results of other AM technologies. Despite the newness of ADAM, significant improvement in surface roughness and comparable results in other properties was observed. However, further research shall be done to optimize the manufacturing parameters in order to increase the relative density value, as it was found to be significantly lower than in other AM technologies

El registro fósil de vertebrados y patrimonio paleontológico más representativo de los pirineos occidentales

Los Pirineos occidentales son un territorio con una notable diversidad geológica y un importante registro fósil, que constituye un gran archivo de paleobiodiversidad. En lo que respecta al registro fósil de vertebrados, los Pirineos occidentales (Región Vasco-Cantábrica, Cuenca de Pamplona y sector noroccidental de la Cuenca del Ebro) son relevantes tanto desde el punto de vista de los yacimientos paleontológicos como de las colecciones de fósiles procedentes de ellos. Varios yacimientos de vertebrados forman parte del Inventario de Lugares de Interés Geológico (LIG) con alto o muy alto interés paleontológico en la Comunidad Autónoma del País Vasco. Destacan los yacimientos de peces cretácicos de Zeanuri en Bizkaia, mamíferos eocenos de Zambrana e icnitas miocenas de Salinas de Añana en Álava/Araba y la asociación de vertebrados pleistocenos de Kiputz cerca de Mutriku, en Gipuzkoa. Otros yacimientos notables en el área de estudio deberían ser objeto de iniciativas de geoconservación: es el caso de la cantera de Laño (Condado de Treviño), con asociaciones fi nicretácicas de vertebrados continentales y marinos, los afloramientos con icnitas de aves y mamíferos del Eoceno al Mioceno inferior de Navarra/Nafarroa y la cueva vizcaína de Santa Isabel de Ranero (Pleistoceno), por citar únicamente los ejemplos más sobresalientes. Asimismo, existen colecciones de fósiles de vertebrados en los Pirineos occidentales que destacan por su elevado interés paleontológico, aunque algunos no provengan de LIG reconocidos. Estas colecciones están depositadas en diversos centros e instituciones de Bilbao, Irún, Leioa, Pamplona-Iruñea, y Vitoria-Gasteiz. La valoración de la paleobiodiversidad y el registro fósil es un paso importante para el conocimiento del patrimonio paleontológico de un territorio y la creación de fi guras de geoconservación (e.g., LIG, geosites). Sin embargo, la mera inclusión de los yacimientos paleontológicos en estas fi guras no garantiza su protección y conservación, ni la adecuada gestión de las colecciones de fósiles procedentes de ellos. Por lo tanto, es necesario diseñar estrategias de conservación transversales teniendo en cuenta las particularidades de cada yacimiento y/o colección. La divulgación científi ca y cultural del patrimonio paleontológico de un territorio, como el aquí estudiado, debe contar con una mayor colaboración entre los paleontólogos que han valorado los bienes paleontológicos y los técnicos que los gestionan. Para ello, es necesaria la disposición de partidas presupuestarias específicas que posibiliten el desarrollo de diferentes acciones encaminadas a la investigación, conservación y difusión social de este patrimonio.The western Pyrenees is a territory with a remarkable geodiversity and an important fossil record, which constitutes a large archive of palaeobiodiversity. With respect to the vertebrate fossil record, the western Pyrenees (Basque-Cantabrian Region, Pamplona Basin and the north-western sector of the Ebro Basin) are relevant both from the point of view of palaeontological sites and fossil collections. Several vertebrate fossil sites are integrated into the Inventory of Geological Interest Sites (LIG) with high to very high palaeontological interest of the Autonomous Community of the Basque Country. It is worth highlighting the Cretaceous fish sites of Zeanuri in Biscay, Eocene mammals of Zambrana and Miocene ichnites of Salinas de Añana in Araba, and the Pleistocene vertebrate fossil assemblage of Kiputz near Mutriku, in Gipuzkoa. Other highly significant sites in the study area should be subject to geoconservation initiatives. This is the case of the Laño quarry in the Condado de Treviño, which has provided continental and marine vertebrate fossil assemblages from the latest Cretaceous, Eocene to Early Miocene sites with bird and mammal tracks in Navarre, and the Pleistocene cave deposits of Santa Isabel de Ranero in Biscay, to mention only the most outstanding examples. There are also vertebrate fossil collections in the western Pyrenees that stand out for their high palaeontological interest, although some do not come from recognized LIG. These collections are deposited in several centres and institutions of Bilbao, Irun, Leioa, Pamplona-Iruñea and Vitoria-Gasteiz. The valuation of the palaeobiodiversity and fossil record is an important step for the study of palaeontological heritage of a territory and the set-up of geoconservation designations (e.g., LIG, geosites). However, the mere inclusion of the palaeontological assents in these geoconservation designations does not guarantee either their protection and conservation or the suitable management of the fossil collection. Therefore, it is necessary to design conservation strategies taking into account the particularities of each palaeontological site and/or fossil collection. The scientific and cultural dissemination of the palaeontological heritage of a territory like one studied here should have greater collaboration between the palaeontologists that have valued the palaeontological assets and the technicians and institutions that manage them. This requires the provision of specific budgetary items that enable the development of the different activities of research, conservation and social dissemination of this heritage.Fil: Badiola, Ainara. Universidad del País Vasco; EspañaFil: Arlegi, Mikel. Universidad del País Vasco; España. Université de Bordeaux; FranciaFil: Astibia, Humberto. Universidad del País Vasco; EspañaFil: Bardet, Nathalie. Centre National de la Recherche Scientifique; Francia. Muséum National d'Histoire Naturelle; Francia. Université Pierre et Marie Curie; FranciaFil: Berreteaga, Ana. Universidad del País Vasco; EspañaFil: Corral, J. Carmelo. Museo de Ciencias Naturales de Álava/; EspañaFil: Díaz Martínez, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; ArgentinaFil: Gómez Olivencia, Asier. Universidad del País Vasco; España. IKERBASQUE. Basque Foundation for Science; España. Universidad Carlos III de Madrid. Instituto de Salud; EspañaFil: Lopez Horgue, Mikel A.. Universidad del País Vasco; EspañaFil: Perales Gogenola, Leire. Universidad del País Vasco; EspañaFil: Pereda Suberbiola, Xabier. Universidad del País Vasco; Españ

New fossils of Sirenia from the Middle Eocene of Navarre (Western Pyrenees) : the oldest West European sea cow record

Postcranial remains of Sirenia from the early Middle Eocene (late Lutetian) Urbasa-Andia Formation of Navarre (Western Pyrenees) are described. The material consists of two partial atlas vertebrae, one humerus and several dorsal ribs (from Arrasate, Urbasa plateau), and partial dorsal ribs (from Lezaun, Andia plateau). The morphology of the fossils is consistent with referral to Dugongidae, the only sirenian clade known so far in the Middle Eocene of Europe. Moreover, the histological study of the ribs shows that the pachyosteosclerosis of extant Sirenia was definitively present by the early Middle Eocene. The oldest sirenian remains reported to date in the Pyrenean Realm were assigned to the Biarritzian, a regional stage that is currently ascribed either to the middle or to the lower-middle Bartonian. Therefore, the sirenian remains of Lezaun, reliably dated as late Lutetian (SBZ16 zone) in age, are definitively the earliest sirenian fossils known in Western Europe and are among the oldest sea cow records of Europe

Bovidae (artiodactyla, mammalia) del mioceno medio de Tarazona de Aragon (depresión del Ebro, provincia de Zaragoza)

18 páginas, 11 figuras, 5 tablas, 3 láminas.[ES] Se describen restos fósiles dentarios, craneales y postcraneales pertenecientes a la familia Bovidae del yacimiento de Tarazona de Aragón. Según las características morfológicas y métricas de la dentición y los núcleos óseos, existen dos formas en este yacimiento del Mioceno medio de la Cuenca del Ebro. Una ha sido atribuida al género Eotragus y clasificada como E, aff. sansaniensis, mostrando características más derivadas que el resto de las formas ibéricas del mismo género. La otra se clasifica, provisionalmente, como aff. Tethytragus, ya que guarda similitudes con la especie ibérica Tethytragus langai y diferencias evidentes con respecto a Eotragus. Los dos taxones se diferencian netamente respecto a la talla, hipsodoncia y morfología de la dentición; sobre todo, las diferencias de desarrollo y prominencia de los estilos/estílidos y costillas mismos son evidentes,[EN] In this paper cranial, dental and postcraneal fossil remains of the Bovidae family from Tarazana de Aragón are described. There are two forms in this Middle Miocene paleontological site of the Ebro Basin according to the metric and morphological characteristics of the dentition and hom cores. One form is referred to Eotragus and classified as E. aff. sansaniensis, showing more developed features than the other Iberian forms of the same genus. The other form is classified provisionally as aff. Tethytragus because it is quite similar to the Iberian Tethytragus langai and differs from Eotragus. The two bovids from Tarazana show differences in size, hypsodoncy and dental morphology, especially the differences of development and prominence of the styles/stylideds and ribs are obvious.Este estudio se ha llevado a cabo en el contexto del desarrollo del Proyecto de Investigación PB92-0066 de la DGICYT del Ministerio de Educación y Ciencia.Peer reviewe