Efecto de la orientación de los rodillos en la resistencia mecánica de estructuras 3D porosas de SiC fabricadas mediante impresión de filamento

[EN] The present work explores the strength enhancement via minor modifications of the pat-tern design in pure light SiC woodpile structures created by filament printing. In particular,the effect of the filament stacking angle on both the compression resistance and the elasticmodulus of these structures are evaluated. Different patterns were designed while main-taining the bulk structure density, therefore the differences in the mechanical data (strengthand elastic modulus) are not attributable to density variations. All of these materials werepartially sintered at intermediate temperature for additional porosity enhancement. More-over, SiC specimens made by full filament overlapping were produced to serve as referencemassive material. Remarkably, the massive SiC printed material displays ordered sphericalporosity and a closed-pore foam appearance, thus revealing a novel route for producingthese type of porosity. Results evidence that the structure robustness can be tuned throughslight design modification, which thus offers the possibility of further structure lighteningwithout reducing the target strength.[ES] El presente trabajo explora la mejora de la resistencia mecánica de estructuras ligeras for-madas por apilamiento de rodillos de SiC puro, procesadas por impresión directa de tinta, através de modificaciones menores del patrón de dise ̃no. En particular, se evalúa el efecto del ángulo de apilamiento de los filamentos sobre la resistencia a la compresión y el móduloelástico de estas estructuras. Los diferentes patrones fueron dise ̃nados manteniendo sim-ilares densidades aparentes de las estructuras, por lo tanto, las diferencias observadas enlos resultados mecánicos (resistencia y módulo elástico) no son atribuibles a variaciones dedensidad. Todas las estructuras se sinterizaron parcialmente para mantener una elevadaporosidad. Además, se produjeron muestras de SiC macizas creadas por la superposiciónde filamentos utilizadas como material masivo de referencia. Curiosamente, este materialmuestra una porosidad esférica y ordenada, y presenta la apariencia típica de esponjas conporosidad cerrada, mostrando en consecuencia una ruta alternativa para la fabricación deeste tipo de materiales celulares. Dado que la robustez de estructuras 3D se puede maximizara través de una ligera modificación del dise ̃no, esto permitiría alternativamente aligerar aúnmás las estructuras sin perjudicar su resistencia.This work was supported by projects MAT2015-67437-R and RTI2018-095052-B-I00 financed by the Ministerio de Ciencia, Innovación y Universidades MCIU (previously MINECO),Spain/FEDER (UE). J.J. Moyano acknowledges the financialsupport of MCIU/FEDER through the FPI contract ref: BES-2016-077759Peer reviewe

Actas XVIII Reunión Argentina de Sedimentología y IX Congreso Latinoamericano de Sedimentología

El Libro de Actas de la XVIII Reunión Argentina de Sedimentología (RAS) y IX Congreso Latinoamericano de Sedimentología (CLS) contiene los resúmenes de las conferencias invitadas y de todas aquellas presentaciones expuestas tanto en formato póster como oral durante los días 19 al 22 de septiembre de 2023 en la ciudad de La Plata.Centro de Investigaciones GeológicasFacultad de Ciencias Naturales y Muse

Application of a robust QFT linear control method to the course changing manoeuvring of a ship

This paper describes in detail the design methodology of a robust QFT (Quantitative Feedback Theory) controller for the control of the course changing of a ship. A linear model is used with uncertainty in the parameters. The system is designed to fulfil the specifications of robust stability and robust tracking of a reference system

Use of Nanomaterials in the Stabilization of Expansive Soils into a Road Real-Scale Application

Stabilization is a traditional strategy used to improve soils with the main objective of ensuring that this base is compliant with the technical specifications required for the subsequent development of different infrastructures. This study proposes the use of commercial nanomaterials, based on a solution of silicates, to improve the technical characteristics and bearing capacity of the expansive soil. A physical–chemical property study was carried out on the additive nanomaterial. Subsequently, different mixtures of expansive soil, selected soil and artificial gravel with quicklime and commercial nanomaterials were developed to evaluate the improvement obtained by the use of nanomaterials in the technical characteristics of the soil. Compressive strength and the Californian Bearing Ratio index were considerably increased. A full-scale study was carried out in which the nanomaterial product was applied to two different sections of stabilized road compared to a control section. The results obtained showed that the use of nanomaterial led to the possibility of reducing the control section by 30 cm, thus achieving less use of quicklime and a mechanical means for preparing the road section. The use of commercial nanomaterial improved the behavior of the stabilized sub-base layer. Through life cycle assessment, this study has shown that the use of nanomaterials reduces the environmental impact associated with soil stabilization.FEDER/Ministerio de Ciencia, Innovacion y Universidades-Agencia Estatal de Investigacion/Ecaryse RCT-2017-6202-

Validacion de un instrumento de medicion de satisfaccion de usuarios de productos y servicios informaticos

160 p.La investigación presente esta basada en un estudio realizado en Norteamerica por dos investigadores. El estudio efectuado aporta con un instrumento que sirve p medir la satisfacción de los usuarios de productos y servicios informáticos, empresas norteamericanas. Este instrumento de medición contiene 39 factores influencian la satisfacción de los usuarios, y estos últimos, al evaluar los factores ha( que se llegue a determinar una medida cuantitativa de satisfacción. En el caso de Chile, y mas específicamente, de la Región del Maule, los facto se obtuvieron a través de consultores y/o expertos informáticos, quienes indicaron factores a incluir en el instrumento de medición. Se realizo un censo en gran( empresas (con mas de 150 empleados) de tipo industrial con la condición que el tuvieran un departamento de informática. El censo se realizo a las 32 empresas c cumplían con la condición, obteniendo respuesta de solo 30 de ellas. El análisis de datos, obtenidos a través de una encuesta fue realizado con apoyo de técnicas y SW estadísticos. Los resultados revelaron que los factores difieren, aunque no en gran medida, los factores que influencian la satisfacción de los usuarios norteamericanos. Además se observo que el nivel de satisfacción de los usuarios de los productos y servicios. informáticos, en la Región del Maule, es moderado, no encontrándose extrenadamente insatisfechos ni extremadamente satisfechos

Force–velocity profiles in CrossFit athletes: A cross-sectional study considering sex, age, and training frequency

Introduction: The force–velocity profile has been analysed previously in different sports modalities; nevertheless, it has not been analysed in CrossFit. Objective: The aim of this study was to report neuromuscular characteristics of CrossFit athletes using their individual force-velocity profile, investigating differences according to sex, age, and training frequency. Materials and Meth-ods: 72 males (33.17 ± 6.86 years; BMI: 25.93 ± 3.64 kg/m2) and 18 females (30.11 ± 6.92 years; BMI: 23.53 ± 3.98 kg/m2) participated in this study. The force-velocity profile was calculated using Samo-zino’s method. Furthermore, neuromuscular characterization was completed with a squat jump and three drop jumps (20, 30, and 40 cm). Results: Regarding sex, significant differences in all analysed mechanical variables (p < 0.001) were found except for the theoretical maximal force (p = 0.944). No significant differences were found between age groups. Considering training frequency, athletes who train more than 5 days per week showed higher performance in all analysed mechanical variables (p < 0.05). Conclusion: CrossFit athletes have a force-velocity profile more oriented towards velocity than force. Males and females have different neuromuscular characteristics, also neuromus-cular improvements can be achieved at any age. Moreover, higher neuromuscular performance is developed with a training frequency of 5 days or more per week

Abordaje de la insuficiencia cardiaca amiloidótica desde la pluripatología

A 88-year-old patient with personal clinical record of heart failure with left ventricular hypertrophy preserved ejection fraction and paroxysmal atrial flutter, is admitted due to a right heart failure, being diagnosed of natural transthyretin cardial amyloidosis. We approach the diagnostic process and its implications under the view of pluripathology which allows us to maintain the balance between nihilism and obstinacy upon the advances of the disease.  Paciente de 88 años con antecedentes de insuficiencia cardíaca, hipertrofia ventricular izquierda con fracción de eyección preservada y flutter auricular paroxístico. Ingresó por insuficiencia cardíaca de predominio derecho, siendo diagnosticada finalmente de amiloidosis cardíaca por transtiretina natural. Abordamos el proceso diagnóstico y las implicaciones del mismo desde una visión global e integradora que nos permite mantener el equilibrio entre el nihilismo y la obstinación ante los avances que se están produciendo en esta enfermedad

Effects of pH and ionic strength on the protease activity of gastric extracts from the Coho salmon Oncorhynchus kisutch

The activity of fish acid proteases is strongly dependent on the pH, and many basic and applied works had focused on researching the pH-profile of digestive proteases using different buffered media. Nevertheless, enzymatic activity is also known to be affected by the ionic strength (IS) of the medium. The present work is aimed at researching the combined effects of pH (2.5, 3.0, 3.5, 3.75 and 4.0) and IS (50, 100 and 200 mM) on the protease activity of gastric extracts of juvenile Coho salmon Oncorhynchus kisutch. It is concluded that the activity of Coho salmon gastric proteases is maximal at pH 2.5-3.0, drops towards pH 4.0 irrespective of ionic strength, and they showed a lower activity at IS 50 mM in comparison to IS 100 or 200 mM. The present results point out to the convenience of considering the effect of ionic strength when measuring the activity of fish gastric proteases

Carbon-Coated Superparamagnetic Nanoflowers for Biosensors Based on Lateral Flow Immunoassays

Superparamagnetic iron oxide nanoflowers coated by a black carbon layer (Fe3O4@C) were studied as labels in lateral flow immunoassays. They were synthesized by a one-pot solvothermal route, and they were characterized (size, morphology, chemical composition, and magnetic properties). They consist of several superparamagnetic cores embedded in a carbon coating holding carboxylic groups adequate for bioconjugation. Their multi-core structure is especially efficient for magnetic separation while keeping suitable magnetic properties and appropriate size for immunoassay reporters. Their functionality was tested with a model system based on the biotin–neutravidin interaction. For this, the nanoparticles were conjugated to neutravidin using the carbodiimide chemistry, and the lateral flow immunoassay was carried out with a biotin test line. Quantification was achieved with both an inductive magnetic sensor and a reflectance reader. In order to further investigate the quantifying capacity of the Fe3O4@C nanoflowers, the magnetic lateral flow immunoassay was tested as a detection system for extracellular vesicles (EVs), a novel source of biomarkers with interest for liquid biopsy. A clear correlation between the extracellular vesicle concentration and the signal proved the potential of the nanoflowers as quantifying labels. The limit of detection in a rapid test for EVs was lower than the values reported before for other magnetic nanoparticle labels in the working range 0–3 × 107 EVs/μL. The method showed a reproducibility (RSD) of 3% (n = 3). The lateral flow immunoassay (LFIA) rapid test developed in this work yielded to satisfactory results for EVs quantification by using a precipitation kit and also directly in plasma samples. Besides, these Fe3O4@C nanoparticles are easy to concentrate by means of a magnet, and this feature makes them promising candidates to further reduce the limit of detectionThis work was supported in part by Spanish Ministry of Economy and Competitiveness under projects MAT2017-84959-C2-1-R and the Principality of Asturias (Spain) under project IDI/2018/000185 and the Consellería de Educación Program for Development of a Strategic Grouping in Materials (AEMAT) at the University of Santiago de Compostela under Grant No. ED431E208/08, Xunta de Galicia. Amanda Moyano was supported by a “Severo Ochoa” fellowship (Consejería de Educación y Cultura del Gobierno del Principado de Asturias, grant BP17-152)S

Metodología cartográfica submarina orientada a la gestión y conservación del medio litoral: mapa de las comunidades bentónicas del frente litoral norte del estrecho de Gibraltar

La cartografía de las comunidades bentónicas es esencial, actualmente, para promover actuaciones eficientes de uso, gestión y conservación de las zonas litorales, especialmente en el ámbito de grandes espacios litorales protegidos. En cada uno de éstos, la cartografía resulta determinante para la elaboración de un mapa de zonificación de usos, condicionado, en gran medida, por los distintos valores ecológicos que puedan asignarse a las diferentes comunidades bentónicas establecidas y a sus distribuciones geográficas locales. La metodología utilizada en la elaboración del mapa de las comunidades bentónicas del estrecho de Gibraltar (en el intervalo batimétrico 0-30 m y de 40 km de extensión litoral aproximada), dada la complejidad que reviste este tipo de objetivos, supone una aproximación a la cartografía de la biota sésil sumergida, en tramos litorales amplios contenidos en áreas protegidas. Se han combinado, mediante superposición de información, datos físicos de batimetría y tipos de fondo, obtenidos mediante técnicas acústicas y convenientemente cartografiados, con datos biológicos de las comunidades bentónicas, obtenidos en campaña intensiva de buceo científico (con la toma de imágenes en sustrato duro, para su ulterior análisis) y mediante dragado (con registros de granulometría y fauna endobentónica en sustrato blando). La información ha sido georreferenciada adecuadamente para su introducción, como capas independientes, en un sistema de información geográfica (SIG).The cartography of benthic communities is, today, essential to promoting adequate strategies for the use, management and conservation of littoral areas, especially if they are large protected zones. In each zone, cartography is necessary to elaborate a management zoning map, depending on the ecological value of the different benthic communities established and on the local geographical distribution. The methodology used in the elaboration of a map including the benthic communities of the Straits of Gibraltar (0-30 m depth; 40 km of littoral extension), in spite of the complexity of these kinds of objectives, represents an approach to the cartography of the submarine sessile biota of large littoral zones of protected ar- eas. The present study combines physical data (bathymetry and type of substrate), collected using acoustic techniques, and biological data (benthic communities), collected during an intensive sampling programme using scuba (hard bottom: image analysis) and dredging (soft bottom: granulometry and benthic fauna). The information has been geoindexed to be inserted, as different layers, into a Geographic Information System (GIS)