Ceramics with eutectic microstructure in the ZrO2–PrOx system

Praseodymium oxides present redox properties analogous to those of Ce‐based systems and have been proposed for catalytic applications in combination with CeO2, ZrO2, or both. However, uncertainties remain concerning the nature and redox behavior of Pr‐rich mixtures, especially with ZrO2. Here we study the eutectic composites of the ZrO2–PrOx system, focusing on the sensitivity of their microstructure, phase symmetry, and composition to variations of the processing atmosphere from oxidizing to reducing. Mixed oxides have been produced by a laser‐assisted directional solidification technique in O2, air, N2, or 5%H2(Ar) environment, and the resulting materials have been analyzed by scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, Raman spectroscopy, and magnetic susceptibility. In air, N2, or 5%H2(Ar) atmosphere, a lamellar, eutectic‐like microstructure forms, the major phase being the one with less Pr content. Both the Pr concentration in each phase as the PrOx molar percentage of the eutectic composites decrease as the atmosphere becomes more reducing. Both eutectic phases are fluorite‐like when processing in air, whereas in N2 or 5%H2(Ar), the phase with high Pr content is of the A‐R2O3 type, and the phase with low Pr content can be described as a fluorite phase containing C‐R2O3‐like short‐range‐ordered regions. The results obtained for samples processed in O2 suggest that for high enough pO2 no eutectic forms, in analogy with the ZrO2–CeO2 system. The evolution of the phase composition and symmetry is discussed in terms of the limited stability of the phases found in the ZrO2–Pr2O3 system, namely, A‐ or C‐R2O3‐like, beyond a certain Pr oxidation degree and oxygen content

The use of crossbreeding with beef bulls in dairy herds: effects on calving difficulty and gestation length

This study was designed to analyse the evolution in the use of beef bull semen for dairy cattle insemination and, mainly, to assess calving difficulty, gestation length and proportion of stillbirths after breeding pure Holsteins or crossbreeding. Data were collected during 2004 to 2011 for 552 571 Holstein calvings (457 070 Holstein × Holstein, 43 384 Holstein × Limousine, 32 174 Holstein × Belgian Blue and 19 943 Holstein × Galician Blonde). The highest calving difficulty, compared with pure Holsteins was for crosses with Belgian Blue followed by Limousine and Galician Blonde. The Holstein × Limousine and Holstein × Galician Blonde crossbred calves had significantly longer gestation lengths than Holstein × Holstein and Holstein × Belgian Blue calves. Between the latter two, pure Holstein had the shortest gestation length. Calving difficulty and gestation length decreased as the age of the dam advanced. The most difficult calvings were observed in twin calvings, followed by the calvings of male calves and female calves. The gestations leading to the birth of male calves were longer than those leading to female calves and twin calves. Stillbirths were not related to the breed used for mating. Through examining these parameters, sire breed should be considered when selecting a beef breed for the insemination of milk-producing damsS

Spectral BRDF-based determination of proper measurement geometries to characterize color shift of special effect coatings

A reduced set of measurement geometries allows the spectral reflectance of special effect coatings to be predicted for any other geometry. A physical model based on flake-related parameters has been used to determine nonredundant measurement geometries for the complete description of the spectral bidirectional reflectance distribution function (BRDF). The analysis of experimental spectral BRDF was carried out by means of principal component analysis. From this analysis, a set of nine measurement geometries was proposed to characterize special effect coatings. It was shown that, for two different special effect coatings, these geometries provide a good prediction of their complete color shift.The authors are grateful to “Plan Nacional de Física” for funding this work (FIS2010-19756-E), to CSIC’s JAE Program, and the “European Social Fund” for awarding us a research trainee. This study was also supported by the Spanish Ministry of Economy and Competitiveness under the grant DPI2011-30090-C02-02 and the European Union

Calibración de la potencia de un microondas mediante un balance de energía en régimen estacionario

Mediante este objeto de aprendizaje se podrá obtener la potencia estimada de un microondas para cada posición de su dial. Para ello, se recurrirá a la aplicación de un balance de energía en estado estacionario que dará lugar al test de los 2LCastelló Gómez, ML.; Cárcel Carrión, JA.; Fito Suñer, PJ.; Tarrazo Morell, J.; Sanjuán Pellicer, MN. (2019). Calibración de la potencia de un microondas mediante un balance de energía en régimen estacionario. http://hdl.handle.net/10251/121661DE

Predicción del tiempo de calentamiento por microondas de un alimento

Con este objeto de aprendizaje se explican las herramientas de cálculo para poder predecir el tiempo de calentamiento de un alimento obtenidas a partir de un balance de energía calorífica. En concreto, se pone como ejemplo la estimación del tiempo de calentamiento de la leche en función de la temperatura que se desea que alcanceCastelló Gómez, ML.; Cárcel Carrión, JA.; Sanjuán Pellicer, MN.; Fito Suñer, PJ.; Tarrazo Morell, J. (2019). Predicción del tiempo de calentamiento por microondas de un alimento. http://hdl.handle.net/10251/121943DE

Balance de Materia de un componente en Régimen Transitorio

En este artículo se explica la metodología para abordar un caso de transporte de materia de un componente (la sal) en una operación básica en la que la variable tiempo está afectando a la concentración de dicho componenteCastelló Gómez, ML.; Tarrazo Morell, J.; Fito Suñer, PJ.; Heredia Gutiérrez, AB.; Cárcel Carrión, JA.; Sanjuán Pellicer, MN. (2020). Balance de Materia de un componente en Régimen Transitorio. Universitat Politècnica de València. http://hdl.handle.net/10251/144728DE

Measuring membrane permeation rates through the optical visualization of a single pore

Membranes are a critical technology for energy-efficient separation processes. The routine method of evaluating membrane performance is a permeation measurement. However, such measurements can be limited in terms of their utility: membrane microstructure is often poorly characterized; membranes or sealants leak; and conditions in the gas phase are poorly controlled and frequently far-removed from the conditions employed in the majority of real processes. Here, we demonstrate a new integrated approach to determine permeation rates, using two novel supported molten-salt membrane geometries. In both cases, the membranes comprise a solid support with laser-drilled pores, which are infiltrated with a highly CO2-selective molten carbonate salt. First, we fabricate an optically transparent single-crystal, single-pore model membrane by local laser drilling. By infiltrating the single pore with molten carbonate, monitoring the gas-liquid interface optically, and using image analysis on gas bubbles within the molten carbonate (because they change volume upon controlled changes in gas composition), we extract CO2 permeation rates with exceptional speed and precision. Additionally, in this arrangement, microstructural characterization is more straightforward and a sealant is not required, eliminating a major source of leakage. Furthermore, we demonstrate that the technique can be used to probe a previously unexplored driving force region, too low to access with conventional methods. Subsequently, we fabricate a leak-free tubular-supported molten-salt membrane with 1000 laser-drilled pores (infiltrated with molten carbonate) and employ a CO2-containing sweep gas to obtain permeation rates in a system that can be described with unprecedented precision. Together, the two approaches provide new ways to measure permeation rates with increased speed and at previously inaccesible conditions

Is Routine Prophylaxis Against Pneumocystis jirovecii Needed in Liver Transplantation? A Retrospective Single-Centre Experience and Current Prophylaxis Strategies in Spain

In liver transplant (LT) recipients, Pneumocystis jirovecii pneumonia (PJP) is most frequently reported before 1992 when immunosuppressive regimens were more intense. It is uncertain whether universal PJP prophylaxis is still applicable in the contemporary LT setting. We aimed to examine the incidence of PJP in LT recipients followed at our institution where routine prophylaxis has never been practiced and to define the prophylaxis strategies currently employed among LT units in Spain. All LT performed from 1990 to October 2019 were retrospectively reviewed and Spanish LT units were queried via email to specify their current prophylaxis strategy. During the study period, 662 LT procedures were carried out on 610 patients. Five cases of PJP were identified, with only one occurring within the first 6 months. The cumulative incidence and incidence rate were 0.82% and 0.99 cases per 1000 person transplant years. All LT units responded, the majority of which provide prophylaxis (80%). Duration of prophylaxis, however, varied significantly. The low incidence of PJP in our unprophylaxed cohort, with most cases occurring beyond the usual recommended period of prophylaxis, questions a one-size-fits-all approach to PJP prophylaxis. A significant heterogeneity in prophylaxis strategies exists among Spanish LT centres.Funding: This study was supported by the Health Research Institute Marqués de Valdecilla. IDIVAL. Santander. NEXT VAL17/07 grant to José Ignacio Fortea Ormaechea

Aprendizaje personalizado para facilitar la inserción en el mercado laboral, mediante la gamificación, a través del uso integrado de mundos y sistemas virtuales de respuesta en el aula para dispositivos móviles con acceso a internet

Integración de una aplicación informática propia como sistema de respuesta (clicker) y una aplicación de entorno simulado para facilitar la evaluación continúa de forma personalizada, aumentar la motivación y rendimiento a bajo coste