Vacuum tribological behaviour of self lubricant quasicrystalline composite coatings

High temperature resistant self-lubricant coatings are needed in space vehicles for components that operate at high temperatures and/or under vacuum. Thick composite lubricant coatings containing quasicrystalline alloys (QC) as the hard phase for wear resistance, have been deposited by thermal spray. The coatings also comprise lubricating materials (silver and BaF2-CaF2 eutectic) and NiCr as the tough component. This paper describes the vacuum tribological properties of TH103, a coating belonging to this family, with excellent microstructural quality. The coating was deposited by HVOF and tested under vacuum on a pin-on-disc tribometer. Different loads, linear speeds and pin materials were studied. The pin scars and disc wear tracks were characterized by EDS-SEM. A minimum mean steady friction coefficient of 0.32 was obtained employing a X-750 Ni superalloy pin in vacuum conditions under 10 N load and 15 cm/s linear speed, showing moderate wear of the disc and low wear of the pin

Vacuum Tribological Behaviour of Self-Lubricating Quasicrystalline Composite Coatings

High-temperature-resistant self-lubricating coatings are needed in space vehicles for components that operate at high temperatures and/or under vacuum. Thick composite lubricant coatings containing quasicrystalline alloys as the hard phase for wear resistance can be deposited by a thermal spray technique. The coatings also contain lubricating materials (silver and BaF2CaF2 eutectic) and NiCr as the tough component. This paper describes the vacuum tribological properties of TH103, a coating of this type, with a very good microstructural quality. The coating was deposited by high-velocity oxygen fuel spraying and tested under vacuum using a pin-on-disc tribometer. Different loads, linear speeds, and pin materials were studied. The pin scars and disc wear tracks were characterised using a combination of scanning electron microscopy and energy dispersive spectrometry. A minimum mean steady friction coefficient of 0.32 was obtained when employing an X750 Ni superalloy pin in vacuum conditions under 10 N load and 15 cm/s linear speed, showing moderate wear of the disc and low wear of the pi

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Copia del S. XVII.Copia digital. España : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 2023ReclamosFoliadoCaja de escritura: 16 x 11 cmPortada de mano de Palomare

GPU-accelerated iterative reconstruction for limited-data tomography in CBCT systems

Standard cone-beam computed tomography (CBCT) involves the acquisition of at least 360 projections rotating through 360 degrees. Nevertheless, there are cases in which only a few projections can be taken in a limited angular span, such as during surgery, where rotation of the source-detector pair is limited to less than 180 degrees. Reconstruction of limited data with the conventional method proposed by Feldkamp, Davis and Kress (FDK) results in severe artifacts. Iterative methods may compensate for the lack of data by including additional prior information, although they imply a high computational burden and memory consumption. Results: We present an accelerated implementation of an iterative method for CBCT following the Split Bregman formulation, which reduces computational time through GPU-accelerated kernels. The implementation enables the reconstruction of large volumes (> 1024 3 pixels) using partitioning strategies in forward- and back-projection operations. We evaluated the algorithm on small-animal data for different scenarios with different numbers of projections, angular span, and projection size. Reconstruction time varied linearly with the number of projections and quadratically with projection size but remained almost unchanged with angular span. Forward- and back-projection operations represent 60% of the total computational burden. Conclusion: Efficient implementation using parallel processing and large-memory management strategies together with GPU kernels enables the use of advanced reconstruction approaches which are needed in limited-data scenarios. Our GPU implementation showed a significant time reduction (up to 48x) compared to a CPU-only implementation, resulting in a total reconstruction time from several hours to few minutes.This work has been supported by TEC2013-47270-R, RTC-2014-3028-1, TIN2016-79637-P (Spanish Ministerio de Economia y Competitividad), DPI2016-79075-R (Spanish Ministerio de Economia, Industria y Competitividad), CIBER CB07/09/0031 (Spanish Ministerio de Sanidad y Consumo), RePhrase 644235 (European Commission) and grant FPU14/03875 (Spanish Ministerio de Educacion, Cultura y Deporte)

FUX-Sim: implementation of a fast universal simulation/reconstruction framework for X-ray systems

The availability of digital X-ray detectors, together with advances in reconstruction algorithms, creates an opportunity for bringing 3D capabilities to conventional radiology systems. The downside is that reconstruction algorithms for non-standard acquisition protocols are generally based on iterative approaches that involve a high computational burden. The development of new flexible X-ray systems could benefit from computer simulations, which may enable performance to be checked before expensive real systems are implemented. The development of simulation/reconstruction algorithms in this context poses three main difficulties. First, the algorithms deal with large data volumes and are computationally expensive, thus leading to the need for hardware and software optimizations. Second, these optimizations are limited by the high flexibility required to explore new scanning geometries, including fully configurable positioning of source and detector elements.This work was funded by the projects TEC2013-47270-R, RTC-2014-3028-1, TIN2016-79637-P, DPI2016-79075-R, and the Cardiovascular Research Network (RIC, RD12/0042/0057) from the Spanish Ministerio de Economía y Competitividad (www.mineco.gob.es/) and, FPU14/03875 grant from the Spanish Ministerio de Educación, Cultura y Deporte (http://www.mecd.gob.es). We also thank NVidia for providing the Tesla K40 device used to perform the experiments

Development and validation of a field inoculation technique of Sclerotinia minor in peanut

Sclerotinia minor causa el tizón del maní, enfermedad que ocasiona pérdidas en el cultivo. Este patógeno produce esclerocios como estructura de resistencia y se encuentra en forma agregada en el campo, lo que dificulta la evaluación de herramientas de control de la enfermedad. Es necesario el desarrollo de una técnica de inoculación que permita la homogeneidad de inóculo en cada unidad experimental. Los objetivos fueron: desarrollar y validar una metodología de inoculación a campo de S. minor en maní, y evaluar el comportamiento de diferentes genotipos del cultivo. Se aislaron y cuantificaron esclerocios de S. minor de muestras de suelo, se seleccionaron subpoblaciones y se produjo inóculo en dos medios de cultivo líquido. El inóculo generado se aplicó a campo sobre diez genotipos y se evaluó la intensidad de la enfermedad y la homogeneidad en la respuesta. El número de esclerocios en suelo fue de 0,81/100 gr antes y 2,07/100 gr después de la inoculación. S. minor creció en ambos medios de cultivo, pero el caldo papa presentó mayores ventajas. La técnica de inoculación fue exitosa, logrando que los valores de incidencia fueran homogéneos entre repeticiones. Se observaron diferencias estadísticamente significativas en el comportamiento de los genotipos frente a la enfermedad.Sclerotinia minor causes peanut blight, a disease that generates losses to the crop. S. minor produces sclerotia as a resistance structure and is found in aggregate form in the field, making it difficult to evaluate disease control tools. It is necessary to develop an inoculation technique that allows homogenizing the inoculum in each experimental unit. The objectives of this work were: to develop and validate a field inoculation methodology for S. minor in peanuts, and to evaluate the behavior of different genotypes of the crop. Sclerotia of S. minor were isolated and quantified from soil samples, subpopulations were selected and the inoculum was produced in two liquid culture media. The inoculum generated was applied in the field on ten peanut genotypes, the intensity of the disease and the homogeneity of response were evaluated. The number of sclerotia in soil was 0.81/100 g before and 2.07/100 g after inoculation. S. minor grew in both culture media, but potato dextrose agar broth presented greater advantages. The inoculation technique was successful at achieving homogenous incidence values among repetitions. Significant statistical differences were observed in the behavior of the genotypes towards the disease.Fil: Rosso, Melina. El Carmen S.A.; ArgentinaFil: Bressano, Marina. Universidad Nacional de Córdoba; ArgentinaFil: de Blas, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Soave, Juan. El Carmen S.A.; ArgentinaFil: Soave, Sara Josefina. El Carmen S.A.; ArgentinaFil: Giordano, Damian Francisco. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria. Departamento de Biología Agrícola; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina. El Carmen S.A.; ArgentinaFil: Oddino, Claudio Marcelo. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria. Departamento de Biología Agrícola; Argentina. El Carmen S.A.; Argentin

Obtención de genotipos de maní resistentes/ tolerantes a factores bióticos y abióticos

Argentina, en la última década, se ha consolidado como el primer exportador mundial de maní (Arachis hypogaea L.) para consumo directo o “maní confitería”. Córdoba es la primera provincia productora con un aporte de más del 96% al total nacional. Entre los problemas comerciales más importantes que el maní de origen argentino enfrenta en el mercado internacional se destaca la amplia variación en los volúmenes ofertados anualmente, debido a las oscilaciones en la producción, lo cual dificulta satisfacer plenamente la creciente demanda internacional. Una de las causas relevantes son los cambios en la superficie que se destina al cultivo los que están fuertemente influenciados por los precios del mercado internacional. Además deben tenerse en cuenta las oscilaciones en los rendimientos obtenidos localmente debido a factores abióticos como la calidad de los suelos y el estrés hídrico, y bióticos como las enfermedades fúngicas, foliares y de suelo. Por lo tanto se propone como solución al tema-problema el desarrollo de nuevos genotipos resistentes/tolerantes a estos factores causantes de las limitaciones en la oferta argentina de maní confitería, innovando en el área de la Biotecnología. Se plantea como objetivo general para este proyecto “Caracterizar y evaluar fuentes de resistencia/tolerancia a factores bióticos y abióticos, particularmente de enfermedades fúngicas con énfasis en carbón y viruelas, y sequía, en genotipos cultivados y silvestres, para desarrollar un sistema de marcadores moleculares que asistan a la selección y transferencia de genes de interés mediante técnicas de mejoramiento convencional; y ajustar las condiciones para la regeneración in vitro de variedades elite de maní cultivadas en Argentina”.Fil: Badariotti, Esteban Hernán. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; ArgentinaFil: Faustinelli, Paola Carmen. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; ArgentinaFil: Bettolli, Fernando Agustín. Universidad Católica de Córdoba. Facultad de Ciencias Químicas; Argentin

ABLE: Automated Brain Lines Extraction Based on Laplacian Surface Collapse.

The archetypical folded shape of the human cortex has been a long-standing topic for neuroscientific research. Nevertheless, the accurate neuroanatomical segmentation of sulci remains a challenge. Part of the problem is the uncertainty of where a sulcus transitions into a gyrus and vice versa. This problem can be avoided by focusing on sulcal fundi and gyral crowns, which represent the topological opposites of cortical folding. We present Automated Brain Lines Extraction (ABLE), a method based on Laplacian surface collapse to reliably segment sulcal fundi and gyral crown lines. ABLE is built to work on standard FreeSurfer outputs and eludes the delineation of anastomotic sulci while maintaining sulcal fundi lines that traverse the regions with the highest depth and curvature. First, it segments the cortex into gyral and sulcal surfaces; then, each surface is spatially filtered. A Laplacian-collapse-based algorithm is applied to obtain a thinned representation of the surfaces. This surface is then used for careful detection of the endpoints of the lines. Finally, sulcal fundi and gyral crown lines are obtained by eroding the surfaces while preserving the connectivity between the endpoints. The method is validated by comparing ABLE with three other sulcal extraction methods using the Human Connectome Project (HCP) test-retest database to assess the reproducibility of the different tools. The results confirm ABLE as a reliable method for obtaining sulcal lines with an accurate representation of the sulcal topology while ignoring anastomotic branches and the overestimation of the sulcal fundi lines. ABLE is publicly available via https://github.com/HGGM-LIM/ABLE .This work was supported by the project exAScale ProgramIng models for extreme Data procEssing (ASPIDE), that has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 801091. This work has received funding from “la Caixa” Foundation under the project code LCF/PR/HR19/52160001. Susanna Carmona funded by Instituto de Salud Carlos III, co-funded by European Social Fund “Investing in your future” (Miguel Servet Type I research contract CP16/00096). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia e Innovación (MCIN) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). Yasser Alemán-Gómez is supported by the Swiss National Science Foundation (185897) and the National Center of Competence in Research (NCCR) SYNAPSY - The Synaptic Bases of Mental Diseases, funded as well by the Swiss National Science Foundation (51AU40-1257).S

Mathematical modelling of the waning of anti-RBD IgG SARS-CoV-2 antibody titers after a two-dose BNT162b2 mRNA vaccination

BackgroundAfter exposure to SARS-CoV-2 and/or vaccination there is an increase in serum antibody titers followed by a non-linear waning. Our aim was to find out if this waning of antibody titers would fit to a mathematical model.MethodsWe analyzed anti-RBD (receptor binding domain) IgG antibody titers and the breakthrough infections over a ten-month period following the second dose of the mRNA BNT162b2 (Pfizer-BioNtech.) vaccine, in a cohort of 54 health-care workers (HCWs) who were either never infected with SARS-CoV-2 (naïve, nHCW group, n=27) or previously infected with the virus (experienced, eHCW group, n=27). Two mathematical models, exponential and power law, were used to quantify antibody waning kinetics, and we compared the relative quality of the goodness of fit to the data between both models was compared using the Akaik Information Criterion.ResultsWe found that the waning slopes were significantly more pronounced for the naïve when compared to the experienced HCWs in exponential (p-value: 1.801E-9) and power law (p-value: 9.399E-13) models. The waning of anti-RBD IgG antibody levels fitted significantly to both exponential (average-R2: 0.957 for nHCW and 0.954 for eHCW) and power law (average-R2: 0.991 for nHCW and 0.988 for eHCW) models, with a better fit to the power law model. In the nHCW group, titers would descend below an arbitrary 1000-units threshold at a median of 210.6 days (IQ range: 74.2). For the eHCW group, the same risk threshold would be reached at 440.0 days (IQ range: 135.2) post-vaccination.ConclusionTwo parsimonious models can explain the anti-RBD IgG antibody titer waning after vaccination. Regardless of the model used, eHCWs have lower waning slopes and longer persistence of antibody titers than nHCWs. Consequently, personalized vaccination booster schedules should be implemented according to the individual persistence of antibody levels

Hypermedia : taller de configuración arquitectónica

El Grupo "Hypermedia. Taller de configuración arquitectónica" lo formamos un colectivo de profesores (doctores y asociados), doctorandos y becarios agrupados en la enseñanza del dibujo y el dibujar como herramienta para la elaboración profesional de proyectos de arquitectura en los primeros (1º y 2º año) semestres de la carrera de Arquitecto Superior. Algunos de nosotros empezamos hace más de 35 años alrededor de los ordenadores, estudiando y simulando procesos de generación de propuestas arquitectónicas. Trabajábamos en el Centro de Cálculo de la Universidad Complutense de Madrid (desde el año 1968, en un seminario denominado: "Análisis y generación de formas arquitectónicas"). Después, desde el 1974, en la Cátedra de Análisis de Formas Arquitectónicas, hemos participado y contribuido a la definición del Área de conocimiento denominada "Expresión Gráfica Arquitectónica" y hemos constituido la asociación de Departamentos del Área de todas las Escuelas de Arquitectura del Estado Español, que, en paralelo, ha creado una Revista especializada (EGA lleva editados 10 números anuales) y sostiene la convocatoria bianual de un Congreso Internacional sobre los temas propios de nuestra especialización. Hoy el Grupo, amplio por razón de la situación estratégica del dibujar (inespecífico, geométrico y arquitectónico) como medio indispensable en el trabajo de proyectar arquitectura, se organiza en varios subgrupos que se reparten puntualmente las preocupaciones y temáticas globales (colectivas) que sistemáticamente aparecen, produciendo gran cantidad de trabajos que, en forma de encargos subvencionados, tesis doctorales, monografías, ponencias y artículos aparecen año tras año en diversos medios de difusión (u edición). Nuestros trabajos no son todos estratégicos, pero son todos (sean o no aplicaciones) centrales en la formación arquitectónica, concernidos con la fundamentación teórica, social, científica y técnica de lo medio ambiental (lo arquitectónico entendido como lo envolvente adecuado al albergue de actividades humanas socializadas)