Enriching the Human Phenotype Ontology with inferred axioms from textual descriptions

The Human Phenotype Ontology (HP) is a reference vocabulary of human phenotypic abnormalities. HP, apart from the textual information (general definitions, descriptions, synonyms, etc.) of each ontology concept, also provides computer-readable logical definitions (axioms) of terms that will allow human phenotypic abnormalities to be related to entities from anatomy, pathology, biochemistry and other areas. In this paper we present a prototype to generate new axiomatic knowledge from the textual descriptions of each HP term. The prototype (i) detects terms in the textual descriptions and not found in the given logical expressions, (ii) generates pair combinations of those terms, (iii) builds triples after detecting the most probable relation between the pair of terms using a statistical model and, finally, (iv) suggests the most probable triples to the user so she can decide which ones can be added to the original axioms

Performance of NiCrAlY Coatings Deposited by Oxyfuel Thermal Spraying in High Temperature Chlorine Environment

A microcrystalline Ni-22Cr-10Al-1Y (wt.%) coating was deposited on AISI 304 stainless steel by the oxyfuel thermal spray technique. The deposited coating was subjected to heat treatment to improve the microstructure characteristics and its corresponding high-temperature properties. The isothermal high-temperature corrosion behavior at 650 and 700 °C in synthetic air and in the presence of 1% Cl2 was investigated using thermogravimetric analysis, x-ray diffraction, and scanning electron microscopy with energy-dispersive x-ray spectroscopy. The results indicated that the deposited NiCrAlY coating possessed acceptable oxidation-corrosion resistance at 650 °C owing to the formation of extensive amounts of the protective oxide of Cr2O3; NiO and a lesser amount of a Cr1.12 Ni2,88 metallic phase are also formed. At 700 °C, the coating lost its protective characteristic because of the excessive consumption of thermodynamically stable phases by oxidation-chlorination process. In this case, the steel base and the coating were attacked by chlorine during the exposure time; the mass gain of the NiCrAlY coating was slightly higher and provided only a limited protection up to 11 h; thereafter, breakdown of the layer of oxides occurred and this is attributed to the formation of non-protective oxides mainly β-Fe2O3 and Fe21.33O32 and the depletion of chromium

Oxidación a 1123 K de sistemas multicapa AISI 304-Ni/Al-Al2O3/TiO2 depositados mediante proyección por llama

The oxidation behaviour of alumina/titania (97/3, 87/13 and 60/40) ceramic coatings using a Ni-Al coupling layer was studied in a thermobalance. Both layers were deposited on an AISI 304 stainless steel base metal by the flame spray technique. The coated steel was heated from room temperature to 1,123 K at 40 K min–1, oxidized in air for 50 h, and then cooled to room temperature at 40 K min–1. The mass gain was mainly attributed to the oxidation of Ni-Al coupling layer. Kinetic laws, DW·S–1 (mg.mm–2) vs. time (hours) were close to a parabolic plot for each sample. Surface composition of ceramic top layer and the cross section of multilayer system were analysed using a wide range of experimental techniques including Scanning Electron Microscopy (SEM), equipped with a link energy dispersive X-Ray spectroscopy (EDX) and X-Ray diffraction (XRD) before and after the oxidation process. Coatings 97/3 and 87/13 presented a stable structure after flame spray deposition and they did not evolve with the oxidation process, while most of the 60/40 coating changed to a metastable structure after deposition and to a more stable structure after oxidation with high micro-cracks content. SEM and EDX microanalysis of the cross-sections showed that significant oxidation and a weak intergranular precipitation had been produced in the coupling layer and on the stainless steel base metal, respectively.El comportamiento a oxidación de recubrimientos cerámicos alúmina/titania (97/3, 87/13, 60/40) usando una capa de anclaje Ni-Al se ha estudiado mediante una termobalanza. Ambas capas se han depositado sobre un acero inoxidable AISI 304 utilizando la técnica de proyección llama (FS). El acero recubierto se ha calentado desde la temperatura ambiente hasta 1.123 K a 40 K min–1, se ha oxidado al aire durante 50 h, y luego se ha enfriado hasta la temperatura ambiente a 40 K min–1. La ganancia en masa se atribuye a la oxidación de la capa de enganche Ni-Al. La cinética DW·S–1 (mg.mm–2) vs. tiempo (horas) se ha ajustado a una ley parabólica para todas las muestras. La composición super- ficial de la capa cerámica y la sección transversal del sistema multicapa se han analizado mediante las técnicas de Microscopía Electrónica de Barrido (SEM), Espectroscopia de Energías Dispersivas de Rayos X (EDX), Difracción de Rayos X (XRD) antes y después del proceso de oxidación. Los recubrimientos 97/3 y 87/13 han presentado una estruc- tura estable tras el proceso de deposición por proyección por llama y esta estructura tampoco ha evolucionado después de la oxidación, mientras la mayor parte del recubrimiento 60/40 ha cambiado a una estructura metaestable después la deposición y finalmente ha evolucionado a una estructura más estable después de la oxidación con alto contenido de microagrietamiento. El microanálisis mediante SEM y EDX de las secciones transversales han mostrado una oxidación significativa en la capa de enganche y una débil precipitación intergranular en el material base AISI 30

Mechanical and tribological properties of alumina/titania coatings deposited by Ooxifuel

En este trabajo se ha estudiado, las fases, las propiedades mecánicas y la resistencia al desgaste abrasivo de recubrimientos cerámicos alumina/titania proyectados por el proceso de oxifuel (spray llama). La proporción de titania tiene una fuerte influencia sobre la porosidad de los recubrimientos, habiéndose observado una disminución casi-lineal de la porosidad con el incremento de titania. Las fases cristalinas que resultan después de la proyección han variado según la naturaleza del polvo y el proceso térmico experimentado. Mientras la dureza obtenida depende sólo del porcentaje en peso de titania, la tenacidad es una función inversa de la dureza, y, la resistencia al desgaste por abrasión es una función creciente con la dureza de los recubrimientosIn this paper the porosity, phases, mechanical properties and abrasive wear resistance of ceramic layers of Al2O3/TiO2 deposited using the flame spray process are evaluated. The proportion of titania has a strong influence on the porosity of the coating, having observed an approximately linear plot decrease with the increasing of titania´s content. Crystalline phases of the deposited layers changed according to the characteristics of the powder and the thermal process employed. It has been observed that hardness depends only on the titania percentage, also toughness decreases with coatings hardness but resistance to abrasive wear traces an increasing lineal plot with this propert

Effects of thermal spraying technique on the remelting behavior of NiCrBSi coatings

This study aims to understand and quantify the influence of the deposition technique on the remelting parameters, microstructure, microhardness, and abrasive behavior of NiCrBSi coatings. An experimental study was conducted on the microstructure and mechanical properties of Ni-based alloys sprayed onto an AISI 304 substrate using two different techniques, namely the flame spraying oxygen–fuel and high-velocity oxygen–fuel techniques, followed by surface flame melting. The microstructures of the resulting coatings were analyzed using optical microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, and X-ray diffraction. The spraying technique is critical for the remelting temperature and time. The microstructures of the deposited coatings in the as-sprayed and remelted samples exhibited similar phases; however, their morphology, size, and distribution were dependent on the deposition technique and remelting parameters, namely temperature and time. Abrasive wear and Vickers microhardness tests were performed. The remelted coatings exhibited higher microhardness, enhanced cohesion of the coating splats, and decreased coating porosity, which decreased wear loss. Although the oxygen–fuel technology after remelting exhibited a relatively larger phase size and lower microhardness than those obtained by high-velocity oxygen–fuel after remelting, a lower wear loss was obtained for the oxygen–fuel. Therefore, this study focused on understanding the effects of as-sprayed and remelted microstructures on wear and microhardness. These findings provide a new understanding of the combination of thermal spraying and remelting techniques for controlling the microstructure and mechanical properties of NiCrBSi coatings