Impact properties and water uptake behavior of old newspaper recycled fibers-reinforced polypropylene composites

Natural fiber-reinforced thermoplastic composites can be an alternative to mineral fiber-based composites, especially when economic and environment concerns are included under the material selection criteria. In recent years, the literature has shown how lignocellulosic fiber-reinforced composites can be used for a variety of applications. Nonetheless, the impact strength and the water uptake behavior of such materials have been seen as drawbacks. In this work, the impact strength and the water uptake of composites made of polypropylene reinforced with fibers from recycled newspaper have been researched. The results show how the impact strength decreases with the percentage of reinforcement in a similar manner to that of glass fiber-reinforced polypropylene composites as a result of adding a fragile phase to the material. It was found that the water uptake increased with the increasing percentages of lignocellulosic fibers due to the hydrophilic nature of such reinforcements. The diffusion behavior was found to be Fickian. A maleic anhydride was added as a coupling agent in order to increase the strength of the interface between the matrix and the reinforcements. It was found that the presence of such a coupling agent increased the impact strength of the composites and decreased the water uptake. Impact strengths of 21.3 kJ/m3 were obtained for a coupled composite with 30 wt % reinforcement contents, which is a value higher than that obtained for glass fiber-based materials. The obtained composites reinforced with recycled fibers showed competitive impact strength and water uptake behaviors in comparison with materials reinforced with raw lignocellulosic fibers. The article increases the knowledge on newspaper fiber-reinforced polyolefin composite properties, showing the competitiveness of waste-based materialsPostprint (published version

Habitat and development. Exploring paths of educational innovation in architecture and urbanism

Han pasado dos décadas desde que aparecieron las primeras asignaturas que incorporaban la habitabilidad básica o la cooperación al desarrollo en la formación del arquitecto en España. Desde entonces, las escuelas de arquitectura han ido incorporando contenidos que son cada vez más demandados, tanto por la sociedad como por los propios alumnos. La crisis económica iniciada en 2008, o los Objetivos de Desarrollo Sostenible aprobados en 2015 por Naciones Unidas, nos deben hacer reflexionar sobre la centralidad de estos temas en la formación de la arquitectura y el urbanismo. Desde el año de su creación, en 2001, la asignatura optativa Hábitat y desarrollo se ha propuesto visibilizar la arquitectura social como una parte importante en la formación del arquitecto, en la que se prioriza el proceso arquitectónico, íntimamente relacionado con el habitar (el habitante, los hábitos y su relación con el lugar), frente al producto (el objeto, el edificio, como una síntesis formal de esa arquitectura). En la asignatura se hace una lectura del papel que la cooperación al desarrollo puede jugar en la formación del arquitecto. La participación ciudadana es otro de los temas transversales que se incorporan en la asignatura, formando a los estudiantes en técnicas específicamente aplicables al campo de la arquitectura y del urbanismo. Hábitat y desarrollo se imparte en el primer semestre de quinto curso del grado en arquitectura de la Universidad de Las Palmas de Gran Canaria.Habitat and development. Exploring paths of educational innovation in architecture and urbanism. It has been two decades since the first subjects that incorporated basic habitability or development cooperation appeared in the training of the architect in Spain. Since then the schools of architecture have been incorporating content that is increasingly demanded by both society and students themselves. The economic crisis initiated in 2008 or the Sustainable Development Objectives approved in 2015 by the United Nations should make us reflect on the centrality of these issues in the formation of architecture and urbanism. Since the year of its creation, in 2001, the optional Habitat and Development has been proposed to make visible the social architecture as an important part in the architect’s training, in which the architectural process is prioritized, closely related to the habitat (the inhabitant, the habits and their relation to the place), in front of the product (the object, the building, as a formal synthesis of that architecture). The subject makes a reading of the role that development cooperation can play in the training of the architect. Citizen participation is another of the cross-cutting themes that are incorporated into the subject by training students in techniques specifically applicable to the field of architecture and urbanism. Habitat and development is taught in the first semester of fifth year of the degree in architecture of the University of Las Palmas de Gran Canaria

The Balanced Cross-Layer Design Routing Algorithm in Wireless Sensor Networks Using Fuzzy Logic

Recently, the cross-layer design for the wireless sensor network communication protocol has become more and more important and popular. Considering the disadvantages of the traditional cross-layer routing algorithms, in this paper we propose a new fuzzy logic-based routing algorithm, named the Balanced Cross-layer Fuzzy Logic (BCFL) routing algorithm. In BCFL, we use the cross-layer parameters’ dispersion as the fuzzy logic inference system inputs. Moreover, we give each cross-layer parameter a dynamic weight according the value of the dispersion. For getting a balanced solution, the parameter whose dispersion is large will have small weight, and vice versa. In order to compare it with the traditional cross-layer routing algorithms, BCFL is evaluated through extensive simulations. The simulation results show that the new routing algorithm can handle the multiple constraints without increasing the complexity of the algorithm and can achieve the most balanced performance on selecting the next hop relay node. Moreover, the Balanced Cross-layer Fuzzy Logic routing algorithm can adapt to the dynamic changing of the network conditions and topology effectively

Structural properties of various sodium thiogermanate glasses through DFT-based molecular dynamics simulations

We present a study of the structural properties of (x)Na$_2$S-(1-x)GeS$_2$ glasses through DFT-based molecular dynamics simulations, at different sodium concentrations ($0<x<0.5$). We computed the radial pair correlation functions as well as the total and partial structure factors. We also analyzed the evolution of the corner- and edge-sharing intertetrahedral links with the sodium concentration and show that the sodium ions exclusively destroy the former. With the increase of the sodium concentration the ``standard'' FSDP disappears and a new pre-peak appears in the structure factor which can be traced back in the Na-Na partial structure factor. This self organization of the sodium ions is coherent with Na-rich zones that we find at high modifier concentration.Comment: 9 pages, 7 figures; to be published in Phys. Rev.

Computer-aided sketching: incorporating the locus to improve the three-dimensional geometric design

This article presents evidence of the convenience of implementing the geometric places of the plane into commercial computer-aided design (CAD) software as auxiliary tools in the computer-aided sketching process. Additionally, the research considers the possibility of adding several intuitive spatial geometric places to improve the efficiency of the three-dimensional geometric design. For demonstrative purposes, four examples are presented. A two-dimensional figure positioned on the flat face of an object shows the significant improvement over tools currently available in commercial CAD software, both vector and parametric: it is more intuitive and does not require the designer to execute as many operations. Two more complex three-dimensional examples are presented to show how the use of spatial geometric places, implemented as CAD software functions, would be an effective and highly intuitive tool. Using these functions produces auxiliary curved surfaces with points whose notable features are a significant innovation. A final example provided solves a geometric place problem using own software designed for this purpose. The proposal to incorporate geometric places into CAD software would lead to a significant improvement in the field of computational geometry. Consequently, the incorporation of geometric places into CAD software could increase technical-design productivity by eliminating some intermediate operations, such as symmetry, among others, and improving the geometry training of less skilled usersPostprint (published version

Complejidad y construcción de conocimiento

La reflexión que aquí se reporta se propone develar una complejidad emergente en la construcción de saber del estudiantado, centrando la atención en la colaboración y convivencia de quienes aprenden. Un saber que va más allá de la comprensión puramente racional de la realidad, se enfrenta al desafío de abordar cada fenómeno como un todo integrado. En este caso las reducciones o constantificaciones de variables, quedan abiertas a permanente revisión y sujetas a mostrarse insuficientes, en tanto que conocemos cada vez más. Mirar desde la perspectiva de sistemas complejos propicia el estudio y descripción de propiedades emergentes que inician con interacciones entre componentes en donde la no-linealidad puede dar lugar a fenómenos en una escala de organización superior. Se constata la relevancia central de una configuración compleja en una propuesta formativo-evaluativa para los aprendizajes matemáticos

HABYTED y ACOES. Dos caminos, dos velocidades. Procesos de participación en arquitectura y urbanismo

El 29 de octubre de 1998, el huracán Mitch, de categoría 5, entró a Centroamérica por la costa de Honduras y, durante los siguientes tres días se desplazó lentamente por el país provocando devastación y muerte. En los meses posteriores, una oleada de solidaridad convirtió a Honduras y a otros países de la región en el centro de atención de la comunidad internacional. Se presenta en este texto una nueva mirada sobre esa experiencia vivida en Honduras, hace más de 20 años, en relación con dos dimensiones: la primera tiene que ver con el subprograma XIV del Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (denominado HABYTED) y la segunda con el proyecto de la Asociación Colaboración y Esfuerzo (ACOES) de Honduras, que en 2020 recibió el premio Derechos Humanos Rey de España. Si el primero fue punto de encuentro para la “Vivienda de interés social” en América Latina, que en 1999 promovió el desplazamiento a Honduras de una misión de HABYTED para realizar una evaluación de las consecuencias del impacto del huracán sobre la habitabilidad básica del país —incluido algún proyecto de transferencia tecnológica en materia de vivienda—, el segundo momento relacionado con esta investigación lo encontramos en la ACOES, fundada en 1993, que aún realiza una ingente labor pedagógica y educativa, e incluye la construcción de centros educativos y viviendas, entre otras iniciativas

A proposal for an Internet of Things-based monitoring system composed by low capability, open source and open hardware devices

The Internet of Things makes use of a huge disparity of technologies at very different levels that help one to the other to accomplish goals that were previously regarded as unthinkable in terms of ubiquity or scalability. If the Internet of Things is expected to interconnect every day devices or appliances and enable communications between them, a broad range of new services, applications and products can be foreseen. For example, monitoring is a process where sensors have widespread use for measuring environmental parameters (temperature, light, chemical agents, etc.) but obtaining readings at the exact physical point they want to be obtained from, or about the exact wanted parameter can be a clumsy, time-consuming task that is not easily adaptable to new requirements. In order to tackle this challenge, a proposal on a system used to monitor any conceivable environment, which additionally is able to monitor the status of its own components and heal some of the most usual issues of a Wireless Sensor Network, is presented here in detail, covering all the layers that give it shape in terms of devices, communications or services

Nitrate- and nitric oxide-induced plant growth in pea seedlings is linked to antioxidative metabolism and the ABA/GA balance

This study looks at the effects of potassium nitrate (KNO3) and sodium nitroprusside (SNP), a nitric oxide (NO)-donor, on the development, antioxidant defences and on the abscisic acid (ABA) and gibberellin (GA) levels inpea seedlings. Results show that 10 mM KNO3and 50μM SNP stimulate seedling fresh weight (FW), althoughthis effect is not reverted by the action of 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide(cPTIO), a NO-scavenger.The KNO3treatment increased peroxidase (POX) and ascorbate oxidase (AOX) activities. SNP, on the otherhand, reduced monodehydroascorbate reductase (MDHAR) activity and produced a significant increase in su-peroxide dismutase (SOD), POX and AOX activities. The“KNO3plus cPTIO”treatment increased ascorbateperoxidase (APX), MDHAR, glutathione reductase (GR) and SOD activities, but POX activity decreased in re-lation to the KNO3treatment. The“SNP plus cPTIO”treatment increased APX and MDHAR activities, whereas ahuge decrease in POX activity occurred. Both the KNO3and the SNP treatments increased reduced ascorbate(ASC) concentrations, which reached control values in the presence of cPTIO. All treatments increased thedehydroascorbate (DHA) level in pea seedlings, leading to a decrease in the redox state of ascorbate. In the“KNO3plus cPTIO”treatment, an increase in the redox state of ascorbate was observed. Glutathione contents,however, were higher in the presence of SNP than in the presence of KNO3. In addition, KNO3produced anaccumulation of oxidised glutathione (GSSG), especially in the presence of cPTIO, leading to a decrease in theredox state of glutathione. The effect of SNP on reduced glutathione (GSH) levels was reverted by cPTIO, sug-gesting that NO has a direct effect on GSH biosynthesis or turnover.Both the KNO3and SNP treatments produced an increase in GA4 and a decrease in ABA concentrations, andthis effect was reverted in the presence of the NO-scavenger. Globally, the results suggest a relationship betweenantioxidant metabolism and the ABA/GA balance during early seedling growth in pea. The results also suggest arole for KNO3and NO in the modulation of GA4 and ABA levels and antioxidant metabolism in pea seedlings.Furthermore, this effect correlated with an increase in the biomass of the pea seedlingsinfo:eu-repo/semantics/acceptedVersio

The effects of native shrub, fencing, and acorn size on the emergence of contrasting co-occurring oak in Mediterranean grazed areas

Producción CientíficaResearch Highlights: The regeneration of Quercus species is usually very difficult in many oak woodlands transformed by livestock farming. Some studies have reported that shrubs can facilitate regeneration. However, the strength of interaction may vary depending on, among other factors, the shrub species and the stress tolerance of the oak species. Moreover, further studies are necessary to clarify the relative importance of the two facilitation mechanisms in the same community. Background and Objectives: Cytisus multiflorus (L’Her.) Sweet is a predominant shrub species in the Mediterranean grazed open-oak-woodlands found in the central west of the Iberian Peninsula (bioclimatic limit) and is present with Quercus pyrenaicaWilld and Quercus ilex subsp. ballota Samp trees. Thus, we assessed the effect of these native shrubs and acorn size, and the effect of excluding large herbivores, on the seedling emergence of two contrasting co-occurring Quercus species under a bioclimatic limit. Materials and Methods: A manipulative field experiment was carried out considering four treatments as a combination of shrubs (shrub/no-shrub) and fence (fenced/open) factors. A total of twenty plots, five replicates for each treatment were available. In each plot, 20 acorns were sown: 10 acorns (5 small and 5 large) for each Quercus species. Acorn emergence was recorded during the first four years following the sowing. Results: Seedling emergence took place mostly in the spring of the first year after sowing. The presence of shrub was the main significant factor and incremented the emergence of both Q. ilex and Q. pyrenaica. The effect of the fence depended on the Quercus species considered, improving only the emergence of Q. pyrenaica. A negative effect with the small acorns was detected but only for Q. pyrenaica. In all treatments, Q. ilex emerged more than Q. pyrenaica. Conclusions: C. multiflorus had a clear facilitative effect on the seedling emergence of Q. ilex and Q. pyrenaica, which was much greater than the physical effect that acorn size and excluding large herbivores had. As such, this native shrub may have a key role in oak regeneration in Mediterranean grazed areas. Furthermore, in these areas of contact between marcescent and sclerophyllous Quercus species, Q. ilex currently emerges more than Q. pyrenaica. This could be indicative of a shift towards more xeric climatic conditions, which could lead to a change in the dominant tree species in the future. However, this change could be modulated by the effects of native shrub and large herbivores.Junta de Castilla y León - (Project SA013G19)Universidad de Salamanca - (Programa de financiación de grupos de investigación (2014/00165/001)