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La innovación debe ser un mecanismo prioritario para un gobierno que desea un desarrollo económico. Las pequeñas y medianas empresas requieren de modelos innovadores que les permitan modernizarse y ofrecer productos y servicios acordes a la evolución de los mercados de consumo. Así­ mismo se hace necesario desarrollar procesos que permitan gestionar el que se puede considerar uno delos activos mas grandes de cualquier organización: el conocimiento. Como cada empresa pose un conocimiento tácito proveniente de cada elemento que la conforman, se hace imperativo el lograr la gestión del mismo a lo largo de toda la organización lo que garantizara el aprendizaje oportuno a través de la creación y trasferencia del mismo lo que significara ventajas competitivas en términos de productos y procesos. Como resultado, se realizo la propuesta de un modelo de gestión del conocimiento para la pequeña y mediana empresa que inicia desde la Alta dirección y permea a toda la organización. Este permitirá a los gestores-propietarios contar con elconocimiento en la generación y sostenimiento de ventajas competitivas en el mercado global. Incluye referencias bibliográficas.

En el presente artí­culo se realizó un análisis estadí­stico aplicando la metodologí­a Hold winters y análisis de varianza sobre una base de datos de preparación de medicamentos oncológicos de una clí­nica de mediana complejidad. Los datos fueron obtenidos organizando la información en tablas dinámicas relacionando el nombre de medicamentos, mes, año y numero de unidades de medicamentos adecuados, de estos datos fueron seleccionados seis medicamentos teniendo en cuenta los diagnósticos y el numero de unidades de medicamentos mas prevalentes durante el periodo de estudio. Posteriormente los datos fueron desglosados en series de tiempo, a las que fue aplicada la metodologí­a Hold winters, que arrojo como resultados la predicción de la cantidad probable de medicamentos adecuar durante los dos años posteriores. Luego estos datos pronosticados fueron comparados con los datos reales de adecuación de los medicamentos seleccionados. Los resultados del análisis de varianza fueron diferencias muy significativas lo cual quiere decir que no hay coincidencias entre los datos pronosticados y los datos reales. Estos resultados podrí­an mejorar si toman en consideración algunas variables como los cumplimientos de esquemas terapéuticos, ciclos de quimioterapia, estadio de la enfermedad, número de pacientes crónicos entre otros. Incluye referencias bibliográficas (páginas 14-15).

Este artí­culo es de carácter exploratorio e indaga sobre la pregunta ¿Cuáles son las relaciones entre responsabilidad social empresarial e innovación social? Con el propósito de identificarlos ejes relacionales que pueden dar soporte a los modos de relacionamiento entre las universidades y las empresas más allá del filantropismo. El artí­culo se estructura a partir dela revisión de los artí­culos publicados durante el perí­odo 2010- 2020 en las bases de datos. Como resultado se identifican dos perspectivas. La primera, anclada en la perspectiva de la responsabilidad social empresarial en la dinámica de creación de valor. La segunda, relacionada con la perspectiva de la innovación social basada en la solidaridad Icluye referencias bibliográficas (páginas 7-8).

Las nuevas estrategias educativas centradas en el funcionamiento de cerebro pueden lograr desarrollar las capacidades de aprendizaje de una forma significativa para que su memoria no lo olvide con facilidad como se plantea desde la neurociencia; por consiguiente la educación en la primera infancia debe construir estructuras mentales permanentes donde el docente tiene que liderar este desarrollo cognitivo en los niños, para esto es necesario que ellos conozcan cómo se realizan los procesos mentales durante la enseñanza; en consecuencia el docente debe utilizar estrategias significativas para lograr un aprendizaje duradero, la planificación y adecuación de los ambientes escolares adecuados permitirán el desarrollo de estructuras mentales. En este sentido el docente debe estar en continua formación utilizando herramientas planteadas porla neurociencia donde se aprovecha de una forma efectiva la plasticidad del cerebro, el trabajo en equipo, la creatividad, la motivación y las emociones de cada estudiante permitiendo así­ la construcción de estructuras mentales desde la primera infancia. De esta manera la neurociencia esuna herramienta que puede potenciar a todas las ramas de la educación en miras de mejorar los procesos de aprendizaje. Incluye referencias bibliográficas.

La forma como los usuarios de automóviles en la ciudad de Cartagena compran partes y repuestos de automóviles no es la mejor, la información de proveedores esta descentralizada, en caso de encontrar un proveedor no se tiene certeza de la calidad delos productos ofrecidos. Hay otros proveedores que ofrecen productos de buena calidad que no figuran en los medios actuales de publicidad, así­ como también algunos otros dicen ofrecer productos nuevos cuando en realidad son productos usados en buenas condiciones como productos remanufacturados. En el presente artí­culo estaremos analizando la problemática, así­ como también consultando propietarios de vehí­culos y otros compradores de autopartes y mirar como una herramienta tecnológica que este a la mano de todos, una aplicación móvil con presencia en la web también podrí­a ayudar la problemática. Para llegar a ser lo más empáticos posible con los usuarios finales se utiliza el método Design Thinking para mediante su método llegar al prototipo que mejor cubra lo que los usuarios están esperando. Incluye referencias bibliográficas (página 9).

El presente artí­culo consiste en la propuesta de un modelo de gestión comercial para el mejoramiento del desempeño de los negocios dedicados al agenciamiento comercial en el sector de las telecomunicaciones en Cartagena; este le permita abarcar los procesos comerciales y el mejoramiento de estos en las organizaciones de este tipo, dándole una mirada 360, que conlleve a la mejora continua y a la estabilidad contractual del personal de ventas. La postura de este modelo de gestión busca diagnosticar los factores crí­ticos y detonantes del negocio, integrará mejoras en los procesos como, reclutamiento, inducción, capacitación, acompañamiento, asesorí­a y seguimiento dela ejecución comercial desde la oportunidad del negocio hasta cierre de este; lo que le dará una visión amplia y estable para la continuidad financiera y comercial de los negocios dedicados a esta actividad comercial. Incluye referencias bibliográficas.

Many studies performed on multifunctional properties of epoxy based nanocomposites reinforced with carbon nanotubes (CNTs) and nanoclay (NC) whereas their synergetic effects on piezoresistive behaviour of ternary state nanocomposites still remains unaddressed. Therefore, the hybrid effects of double-walled CNTs (DWCNTs) and NC on the mechanical, electrical and piezoresistive performances of the epoxy were addressed in this study. Nanocomposites were prepared in two different states, i.e. the binary state (DWCNTs/epoxy) and the ternary states (DWCNTs-NC/epoxy). SEM, FESEM, and XRD were used for the microstructural analysis of the materials while tensile and mode I fracture tests were performed for mechanical and piezoresistive characterizations. The addition of NC to CNTs doped epoxy resulted in a better CNT dispersion, hindering CNT re-agglomeration. A significant increase in KIC (94%) and GIC (254%) compared to the neat epoxy was obtained for the hybrid nanocomposites loaded at 1 wt% NC due to crack bridging and crack deflection. The electrical conductivity of the ternary state materials increased by 700% and 400% with respect to the binary nanocomposite, for 0.5 wt% and 1 wt% NC loadings, respectively. The hybrid nanocomposites also manifested higher piezoresistivity and a more robust signal in tensile and fracture tests, respectively.

El presente artí­culo pretende analizar el impacto que tienen las habilidades blandas enfocadas a la innovación derivadas de los diferentes retos profesionales y personales qué como individuo vivimos a lo largo de nuestra vida. Se ha realizado una revisión de información literaria y unas entrevistas con el objetivo de identificar si las personas a través de los retos afrontados han desarrollado o no habilidades blandas valoradas en el ámbito laboral, además de todas aquellas cualidades, competencias, actitudes cerebrales asociadas con el estado de flujo para logran tener una vida potencialmente en plenitud. Incluye referencias bibliográficas (página 11) y anexo.

La complejidad organizacional, los cambios vertiginosos del entorno y el ambiente de incertidumbre, en el cual gravitan las organizaciones del siglo XXI, demanda gerentes con una arquitectura intelectiva y estratégica para orientar su futuro, siendo necesaria una visión compartida de la gestión de la innovación, esquema obligado para la competitividad después de la pandemia del COVID-19, Este articulo tiene como objetivo socializar parte delos resultados de la experiencia investigativa en los establecimientos hoteleros del Distrito Especial Turí­stico y Cultural de Riohacha, la cual tení­a como objetivo indagar sobre la cultura de la innovación en este tipo de organizaciones. La investigación se enmarco en el enfoque cuantitativo, de tipo transeccional descriptiva, con diseño no experimental y decampo. Se utilizó la encuesta estructurada, con respuestas múltiple en escala de liker, aplicada a una población de 46 gerentes de hoteles; cuyo instrumento fue validado y medida su confiabilidad mediante el coeficiente de Alpha de Crombac, para el tratamiento e interpretación de los datos se utilizó la estadí­stica descriptiva e inferencial. En cuanto a las conclusiones, se pudo establecer que no se percibe un proceso sistemático, que propicie la cultura de la innovación en los hoteles, no obstante, se evidencian algunas áreas como reservas, marketing y concepto de negocios que presentan innovaciones y se considera quelas personas son claves para la innovación. Incluye referencias bibliográficas.

En los últimos tiempos, las operaciones de las tiendas minoristas enfrentan una variedad de desafí­os y complejidades novedosas. El concepto de tienda retail cada dí­a se ve más notorio entre las tiendas que cada usuario utiliza para comprar sus productos, ya que este tipo de tiendas venden grandes cantidades de productos, pero a muchos clientes diferentes. Normalmente estas tiendas utilizan una alta mano de obra para así­ poder satisfacer los productos demandados. El comercio minorista comprende una gran parte de la economí­a, representando directamente cerca del 6%del PIB de los Estados Unidos en 2016, y alrededor del 4% del PIB de la UE-28 en 2014 (según la Oficina de Análisis Económico de EE. UU. y Eurostat, respectivamente). Dado su impacto en la economí­a, no es sorprendente que el comercio minorista tenga ganado mucha atención de académicos. La empresa escogida para esta investigación en su dinámica de evolución con la apertura de los nuevos puntos de venta ha venido incrementando su personal de forma muy repentina y rápida, lo que ha generado un aumento en el gasto de la nómina provocado por la complejidad de la programación de los turnos de trabajo, Por lo tanto, muchas veces toca tener la cantidad de trabajadores necesarios para cumplir la demanda y no crear cuellos de botella y al mismo tiempo a unas horas después estos mismos trabajadores son subutilizados porque la demanda cambia drásticamente, esto es algo que preocupa al personal administrativo y operativo, ya que para Febrero de 2020 la tienda presenta una nómina de 743 empleados y se espera para finales de2020 con la apertura de nuevos negocios superar los 1000 empleados. Lo que se espera que asi mismo como crece el negocio crecerá el problema para programar el personal y al mismo tiempo lograr aumentara el gasto que genera la nomina de dicha tienda en este tiempo. Al mismo tiempo se crean otros problemas intangibles como lo son los descansos del personal, los dobles turnos, los accidentes laborales por excesivo trabajo, etc. Por lo tanto, con esta investigación se desea desarrollar un modelo matemático capaz de programar el personal de una tienda Retail por lo menos con un mes de anticipación, para así­ lograr disminuir gastos y aumentar productividad, es decir optimizar el proceso de asignación de turnos. Incluye referencias bibliográficas

La cultura de la innovación se posiciona en la actualidad como la meta de las organizaciones para lograr una ventaja organizacional única, la cual llega a ser un beneficio competitivo. Por consideración a esto se enuncia dentro del presente documento las razones principales de la importancia que tiene la innovación como cultura dentro de una empresa, alcanzando entonces la creación de la idea que valide por qué se convierte en la clave adecuada para que las organizaciones destaquen, se sostengan y avancen progresivamente en su ciclo de vida, por ello en el siguiente artí­culo se realiza una investigación dentro de la literatura y la interpretación de la misma, resaltando en el proceso los conceptos claves dentro del conjunto temático. El propósito de este documento es múltiple. Inicialmente, se expone la necesidad de la cultura dela innovación dentro de las organizaciones. Seguidamente se esclarece mediante una revisión bibliográfica los conceptos unilaterales de innovación, cultura, investigación, desarrollo y valor es que forman el conjunto de la temática. Por último, se deja en evidencia la disposición de las organizaciones a incluir la innovación como parte de su cultura. Incluye referencias bibliográficas (página 11).

La investigación pretende identificar las competencias en innovación que son apropiadas por los estudiantes de ingenierí­a industrial de la universidad Minuto de Dios, jornada nocturna, para lo cual se realizo un análisis a los micro currí­culos del programa, con la participación activa del comité curricular, director, coordinador académico, estudiantes egresados, docentes del programa, con el acompañamiento de la comunidad de empresarios de la localidad, para lo cual se aplicó una encuesta individual, cuyos resultados se analizan en un apartado de este documento; sin embargo a continuación de se resaltan algunas de las competencias o habilidades para innovar propias de la Ingeniero Industrial (capacidad de involucrarse en la resolución de problemas, espí­ritu innovador, carácter de negociador, creativo en enfoques nuevos, dominio de idioma inglés, aseguramiento de calidad, entre otros). A partir de ahí­, los resultados permiten contar con una visión clara sobre las competencias que hacen parte integral del profesional en ingenierí­a, utilizando una metodologí­a mixta con corte transversal. Incluye referencias bibliográficas.

Mediante el siguiente artí­culo se hace énfasis en el Servicios del Servicio Nacional de Aprendizaje – SENA de la Regional San Andrés directamente sobre el caso SENNOVA en el área de innovación direccionado hacia su personal administrativo, teniendo en cuenta sus direccionamientos estratégicos, con la finalidad de poder ayudara contribuir con la generación de cultura de la innovación surgiendo la pregunta de investigación de ¿Cómo podrí­amos diseñar un modelo para generar cultura de innovación en personal administrativo SENA regional San Andrés?, a lo que se propuso un modelo basado en dos pasos, inicialmente en el relacionamiento de los focos de las redes de conocimiento con las que se cuentan para luego realizar un proceso de innovador que consta de cuatro (4) pasos como son, ideación, vigilancia tecnológica, definición de la idea y apalancamiento. Mediante una metodologí­a cualitativa descriptiva basado en los aspectos de la comunidad o población beneficiaria y la revisión de la información recolectada de modelos de innovación propuestos; cabe resaltar que las etapas del modelo podrán aplicarse de forma individual y no necesariamente deberá cumplir un proceso lineal. Incluye referencias bibliográficas .

Functionalized graphene nanoplatelets networks created through glass fiber fabrics were used to detect and locate damage in multiscale composite materials. The electrical behavior of multiscale composite materials was strongly influenced by microstructural features. Coated fabrics presented high sensitivity to breakage of fibers due to the preferential orientation of f-GNPs through fibers. This sensitivity was higher when damage was induced perpendicular to the fiber direction and the region where damage could be detected was bigger in the case of locating the measuring electrical channels perpendicular to fiber direction. These phenomena are related again to the morphology of the electrical network through the coating. Due to the insulating character through thickness of composites, detection and location was limited to layers of fabric of the composite. Nevertheless, self-sensors had the capacity of detecting and locating damage with high sensitivity by means of abrupt increases in electrical resistance induced by breakage.

Chromatin remodeling plays a key role in the establishment and maintenance of gene expression patterns essential for plant development and responses to environmental factors. Post-translational modification of histones, including acetylation, is one of the most relevant chromatin remodeling mechanisms that operate in eukaryotic cells. Histone acetylation is an evolutionarily conserved chromatin signature commonly associated with transcriptional activation. Histone acetylation levels are tightly regulated through the antagonistic activity of histone acetyltransferases (HATs) and histone deacetylases (HDACs). In plants, different families of HATs are present, including the MYST family, which comprises homologs of the catalytic subunit of the Nucleosome Acetyltransferase of H4 (NuA4) complex in yeast. This complex mediates acetylation of histones H4, H2A, and H2A.Z, and is involved in transcriptional regulation, heterochromatin silencing, cell cycle progression, and DNA repair in yeast. In Arabidopsis and, other plant species, homologs for most of the yeast NuA4 subunits are present and although the existence of this complex has not been demonstrated yet, compelling evidence supports the notion that this type of HAT complex functions from mosses to angiosperms. Recent proteomic studies show that several Arabidopsis homologs of NuA4 components, including the assembly platform proteins and the catalytic subunit, are associated in vivo with additional members of this complex suggesting that a NuA4-like HAT complex is present in plants. Furthermore, the functional characterization of some Arabidopsis NuA4 subunits has uncovered the involvement of these proteins in the regulation of different plant biological processes. Interestingly, for most of the mutant plants deficient in subunits of this complex characterized so far, conspicuous defects in flowering time are observed, suggesting a role for NuA4 in the control of this plant developmental program. Moreover, the participation of Arabidopsis NuA4 homologs in other developmental processes, such as gametophyte development, as well as in cell proliferation and stress and hormone responses, has also been reported. In this review, we summarize the current state of knowledge on plant putative NuA4 subunits and discuss the latest progress concerning the function of this chromatin modifying complex.

This work aims to investigate the crack propagation monitoring capacity of carbon nanotube (CNT) reinforced adhesive films in joints with dissimilar materials. To achieve this purpose, Mode-II standard tests have been carried out while the electrical response has been determined in terms on electrical resistance measurements. It has been observed that electrical and mechanical response show a good agreement, with an increase of the electrical resistance with crack length due to the breakage of electrical pathways. Brushed and grit-blasted metallic substrates were tested and some significant differences between electrical response have been observed. Samples with poorer surface treatment showed a more unstable response due to a continuous creation and breakage of electrical pathways while grit-blasted specimens present a uniform electrical resistance increase. These results were also stated by microstructural analysis, showing the presence of weak areas in case of brushed substrates. In addition to that, skin-stringer elements were also tested at static conditions, showing a good electrical continuity. Therefore, the potential and applicability of the proposed technique for SHM of bonded joints have been demonstrated

The addition of functionalized graphene nanoplatelets (f-GNPs) into the epoxy resin of glass fiber multiscale composite materials creates an electrically conductive network. This electrical network is highly sensitive to strain induced in the material. For this reason, it is a competitive material to be used in structural health monitoring (SHM). Sensitivity of multiscale composite materials is ∼50 under tensile loads and the behavior under compression loads differs, making possible the detection of different load conditions. Independency of the strain rate is related to the enhanced interface between f-GNPs and the epoxy matrix due to functionalization. Additionally, the electrical behavior is reversible without the loss of efficiency in sensorial properties.

The aim of this study was to explore whether children with and without learning difficulties use orthographic rules to write words. To study this, two types of tasks from the Early Grade Writing As...

En el presente artículo encontraremos algunas de las acciones realizadas por las mujeres colombianas para acceder a la educación superior y cómo estas enmarcan la necesidad de visibilizar y reflexionar acerca de la construcción de una sociedad donde se supere el discurso de la igualdad y se inicie la lucha por la equidad, como característica fundamental del reconocimiento de la mujer. Para ello, abordaremos históricamente el acceso de las mujeres a la educación superior y posteriormente validaremos dos escenarios específicos para realizar un análisis que permita develar el ingreso de las mujeres a las instituciones de educación superior y el compromiso de estas últimas al respecto. Finalmente, será necesario recrear dos historias que trascienden a la acción este derecho ganado por muchas, reconfigurando el papel de la mujer en la sociedad y en la construcción de un país en el que la apuesta fundamental es la educación como una vía posible de cualquier transformación social.

Hybrid multi-material joints of titanium alloy (Ti6Al4V) bonded to carbon fibre reinforced polymer (CFRP) are really interesting for lightweight high-performance structures, i.e., aeronautical and marine applications. Co-bonding technique, in which the joining takes place at the same time as the manufacturing of the CFRP, could be a great solution for easy manufacturing fibre metal laminate (FML) and complex structures, or a time saving process. One of the biggest challenges in this type of multi-material structures is to be able to confirm the structural health in service. The present work deals with the use, as matrix, of an epoxy resin reinforced with multiwalled carbon nanotubes (MWCNT) for manufacturing of Ti-CFRP joints by co-bonding. The aim is the structural health monitoring (SHM) of these hybrid structures, enhancing their mechanical properties. The obtained results show an improvement of more than 140% in fracture resistance of the multi-material joints with optimal surface preparation, by incorporating CNT. Furthermore, electrical monitoring makes it possible to discern the quality of the manufactured joints, increasing their reliability and performance. Besides, the ability to localize crack propagation and stresses prior to joint failure has been confirmed, so CNT addition results in a powerful tool for SHM multi-material joints.

Sensing capabilities of carbon nanotube (CNT) epoxy materials have been studied in order to develop multifunctional coatings for damage detection. For that purposes CNT doped epoxy nmixtures have been manufacturing using toroidal stirring. The microstructural characterization of CNT dispersion has been carried out by optical microscopy, showing the good homogenization effect induced by toroidal stirring. Then, electromechanical tests have been carried out on bulk nanocomposites and strain gauges. From tensile tests, it has been noticed that the Gauge Factor (GF) of strain gauges is much higher than those of bulk nanocomposites and conventional metallic gauges. Bending tests, which gauges made over tensile or compressive faces of the samples show that strain gauges have different behaviors while bulk materials show similar ones due to electrical volume interactions, proving the potential of strain gauges for monitoring complex load states. Damage sensing of CNT/epoxy materials has been also proved by inducing artificial defects on a monitored coating as changes in electrical resistance related to damage size. Thus damage detection, location and quantification have been achieved.

Subunit II of cytochrome c oxidase (Cox2) is usually encoded in the mitochondrial genome, synthesized in the organelle, inserted co-translationally into the inner mitochondrial membrane, and assembled into the respiratory complex. In chlorophycean algae however, the cox2 gene was split into the cox2a and cox2b genes, and in some algal species like Chlamydomonas reinhardtii and Polytomella sp. both fragmented genes migrated to the nucleus. The corresponding Cox2A and Cox2B subunits are imported into mitochondria forming a heterodimeric Cox2 subunit. When comparing the sequences of chlorophycean Cox2A and Cox2B proteins with orthodox Cox2 subunits, a C-terminal extension in Cox2A and an N-terminal extension in Cox2B were identified. It was proposed that these extensions favor the Cox2A/Cox2B interaction. In vitro studies carried out in this work suggest that the removal of the Cox2B extension only partially affects binding of Cox2B to Cox2A. We conclude that this extension is dispensable, but when present it weakly reinforces the Cox2A/Cox2B interaction.

Electromechanical sensing devices, based on resins doped with carbon nanotubes, were developed by digital light processing (DLP) 3D printing technology in order to increase design freedom and identify new future and innovative applications. The analysis of electromechanical properties was carried out on specific sensors manufactured by DLP 3D printing technology with complex geometries: a spring, a three-column device and a footstep-sensing platform based on the three-column device. All of them show a great sensitivity of the measured electrical resistance to the applied load and high cyclic reproducibility, demonstrating their versatility and applicability to be implemented in numerous items in our daily lives or in industrial devices. Different types of carbon nanotubes—single-walled, double-walled and multi-walled CNTs (SWCNTs, DWCNTs, MWCNTs)—were used to evaluate the effect of their morphology on electrical and electromechanical performance. SWCNT- and DWCNT-doped nanocomposites presented a higher Tg compared with MWCNT-doped nanocomposites due to a lower UV light shielding effect. This phenomenon also justifies the decrease of nanocomposite Tg with the increase of CNT content in every case. The electromechanical analysis reveals that SWCNT- and DWCNT-doped nanocomposites show a higher electromechanical performance than nanocomposites doped with MWCNTs, with a slight increment of strain sensitivity in tensile conditions, but also a significant strain sensitivity gain at bending conditions.

The incorporation of graphene nanoplatelets (GNPs) as a coating on glass fibre fabrics for strain monitoring applications was analysed. Non-functionalized and functionalized GNPs were used in order to study the effect of the functionalization in the morphology of the coating and the electrical behaviour of the material. In contrast with non-functionalized GNPs, when NH 2 -functionalized GNPs were used, the nanoparticles adapted to the surface of the fibres causing a major effectiveness of the electrical network created along the fibres, achieving an electrical conductivity in the order of 10 −2 S/m. The sensitivity values, obtained under tensile loads, reached values in the order of 840 up to 16400.

La presente investigación tiene por objetivo demostrar, que la investigación policial en el delito de lavado de activos puede vulnerar los derechos fundamentales de los investigados si no se lleva a cabo con la observancia de los estándares internacionales mínimos del proceso penal garantista. Esto supone la comparación entre la labor policial realizada en el marco del proceso penal de naturaleza inquisitiva, donde la Policía Nacional del Perú dirigía la investigación y el Fiscal hacía suyo el atestado policial, y la investigación policial llevada a cabo dentro del proceso penal de corte acusatorio, propio del Nuevo Código Procesal Penal, donde la Policía Nacional del Perú es una entidad auxiliar del Ministerio Público, quien es el que dirige la investigación.

The mechanical and crack sensing capabilities of CFRP-metal Mode-II coupons and skin-stringer T-joints under bending conditions with carbon nanotube (CNT) doped adhesive films are explored. Different surface treatments of the aluminium substrate are tested (grit blasting and sandpaper brushing). Mode-II energy fracture slightly increases with CNT addition due to the nanoparticle toughening effect when the surface treatment is adequate. However, in the case of brushed specimens, the enhanced lubricant properties of CNTs leads to the promotion of weak interfaces between adhesive and metal substrate. The electrical resistance increases with the load nose displacement with a good correspondence to the crack length. A crack opening effect is herein noticed in the last stages of the Mode-II tests due to the difference between the stiffness of metal and CFRP adherents, which is reflected in a sudden increase of the electrical resistance. These results have been also validated by theoretical analysis. Electromechanical response of T-joints shows a similar behaviour with an increasing sensitivity when placing a CFRP stringer, due to a more prevalent crack opening observed in this type of specimens. Therefore, crack sensing capabilities are demonstrated at both coupon and sub-element level.

The strain-sensing, self-curing and self-heating capabilities of a 3D printed circuit made of a graphene nanoplatelet and carbon nanotube reinforced resin, have been widely explored. These materials exhibit high Joule’s heating effect capabilities that can be used for post-curing processes. More specifically, the values of glass transition temperature reached by Joule’s heating post-curing were very similar to those obtained by conventional oven heating. The temperature profile along each individual ribbon was relatively homogeneous, being an indicative of a good nanoparticle dispersion, confirmed by field emission gun scanning electron microscope analysis. Furthermore, the proposed printed circuits showed excellent strain-sensing capabilities with a much higher strain sensitivity, with a gauge factor of 6–8, in comparison to conventional metallic gauges or bulk nanocomposites, with a gauge factor of around 2, showing also good linearity. In addition, the breakage of individual ribbons can be easily detected by the strain-sensing system as a sharp increase of the electrical resistance. Finally, temperature compensation tests showed that, in case of printed ribbon breakage, it is possible to keep constant the average temperature of the circuit by raising the applied voltage to avoid ice accretion. Thus, with none to two broken ribbons, the 3D printed circuit can act as an efficient anti-icing and de-icing system.

A performance mapping of GNP/epoxy composites was developed according to their electromechanical and electrothermal properties for applications as strain sensors and Joule heaters. To achieve this purpose, a deep theoretical and experimental study of the thermal and electrical conductivity of nanocomposites has been carried out, determining the influence of both nanofiller content and sonication time. Concerning dispersion procedure, at lower contents, higher sonication times induce a decrease of thermal and electrical conductivity due to a more prevalent GNP breakage effect. However, at higher GNP contents, sonication time implies an enhancement of both electrical and thermal properties due to a prevalence of exfoliating mechanisms. Strain monitoring tests indicate that electrical sensitivity increases in an opposite way than electrical conductivity, due to a higher prevalence of tunneling mechanisms, with the 5 wt.% specimens being those with the best results. Moreover, Joule heating tests showed the dominant role of electrical mechanisms on the effectiveness of resistive heating, with the 8 wt.% GNP samples being those with the best capabilities. By taking the different functionalities into account, it can be concluded that 5 wt.% samples with 1 h sonication time are the most balanced for electrothermal applications, as shown in a radar chart.

This paper studies the development and characterization of 3D printed conductive circuits based on epoxy inks doped with carbon nanotubes (CNTs) and/or graphene nanoplatelets (GNPs), which could be used in applications such as electronic circuits, heated seats, Anti-icing and De-Icing Systems (ADIS) or Structural Health Monitoring (SHM) systems, among others. A design of experiments (DOE) has been carried out by the Taguchi method to develop and optimize an ADIS based on a 3D printed circuit, using a conductive ink doped with CNTs/GNPs to achieve Joules heating. The target of the DOE is based on reaching the highest average temperature, which was measured by infrared thermographic analysis, taking also into account the quality of the 3D printed circuits. The DOE factors were the CNT and GNP content, the voltage applied to the circuit and its geometry, proposing two alternative designs. Finally, a de-icing test was carried out with the optimal parameters obtained from the DOE. Results evince the viability of the system developed, being able to melt an ice layer of 2.5 mm thick in 3 min and 30 s.

Many studies were performed to improve CNT dispersion into epoxy using different mechanical dispersion methods as well as CNT functionalization. In this study, a novel method is introduced to enhance CNT dispersion using 2D nanoclay as a secondary filler. Hence, this study was aimed to investigate the effect of nanoclay platelets on electrical, mechanical, and piezoresistive characteristics of the SWCNTs doped epoxy nanocomposites. Two different types of nanocomposites were prepared for comparison including binary (SWCNT/epoxy) and hybrid (SWCNT-nanoclay/epoxy) states. CNT content of 0.1 wt% was used for the binary and hybrid states while two different nanoclay loadings (0.5 wt% and 1.0 wt%) were employed in the hybrid nanocomposites. Tensile and mode I fracture tests were performed for the mechanical and electromechanical characterization using two probe techniques while electron microscopy and X-ray diffraction were used for microstructural analysis. Results showed severe CNT agglomeration in the binary state whilst a homogenous CNT dispersion was achieved in the ternary states. The binary nanocomposite showed weak performance in terms of electrical, mechanical and piezoresistive properties caused by severe CNT aggregates. On the other hand, addition of nanoclay into CNTs doped epoxy manifested a significant increase in the electrical, mechanical and piezoresistive-sensitivity performance of the hybrid nanocomposites compared to the binary one. The best performance was achieved at 0.5 wt% nanoclay loading where electrical conductivity increased by six orders of magnitude, UTS increased by 37%, KIC and GIC increased by 34% and 64%, respectively, with respect to the binary nanocomposite. Crack-pinning and crack deflection were accounted for the fracture toughness increase in ternary composites. Nonlinear piezoresistivity resulting from the predominate effect of tunneling resistance ruled piezoresistivity in the hybrid nanocomposites. A sensitivity of 2.1 and 2.0 at strain of 0.01 were obtained for 0.5 wt% and 1.0 wt% nanoclay contents, respectively, whereas no sensitivity was achieved for the binary composite.

The present study investigates, through experimental and numerical approaches, the incorporation effect of different weight concentrations of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties of epoxy. Tensile and mode I fracture tests were performed to investigate the effect of the addition of MWCNTs on Young’s modulus, Ultimate Tensile Strength (UTS), critical stress intensity factor (KIC) and critical strain energy release rate (GIC). Different carbon nanotubes (CNTs) contents were employed to compare the effect of the resulting microstructures (well-dispersed and agglomerated CNTs) on the mechanical properties. Field Emission Scanning Electron Microscopy (FESEM) and Scanning Electron Microscopy (SEM) were used for microstructural analysis and fractography. Experimental results showed that UTS was improved (28%) by incorporation of MWCNTs while the KIC and GIC were substantially increased by 192% and 614%, respectively. CNT pullout and crack bridging were the main contributing mechanisms in toughening the epoxy at low CNT contents (0.1 and 0.25 wt%). In contrast, a combination of crack bridging and crack branching was responsible for the resin toughening in the case of 0.5 wt% loading. The significant increase for KIC and GIC demonstrated the excellent performance of the dispersion approach used in this study. Finite Element modelling was used to provide a more robust analysis of the effect of CNT incorporation in tension tests and of the toughening mechanism of the nanocomposites in mode-I fracture tests.

Carbon fibers reclamation from waste composites by pyrolysis is developing fast. Pyrolysis allows the reclamation of the fibers by thermal decomposition of the polymeric resin, but the material value of these resins is not yet recovered. In this research work, the possibility of obtaining high-value gaseous fractions by treating the vapors generated in the decomposition of a poly(benzoxazine) containing carbon fiber waste composite has been studied. The experiments have been carried out in a lab-scale facility consisting of two reactors in series. In the first reactor, the pyrolysis of the waste is carried out at 500 °C, while in the second reactor the vapors coming from the first reactor are treated at 900 °C. Such treatment enables to triple the amount of gas in comparison to conventional pyrolysis. Besides, this gas contains 56% by volume of H2, which means the recovery of approximately 60% of the hydrogen contained in the resin. On the other hand, clean carbon fibers with mechanical properties within commercial values have been also obtained.

The influence of dispersion procedure and nanofiller geometry on thermal and electrical properties of graphene nanoplatelet (GNP) based composites has been investigated. A theoretical model, based on the contacts between adjacent nanoparticles, has been proposed aiming to connect thermal and electrical properties. It has been observed that GNP overlapping (type I) induces a decrease on thermal conductivity. Its effect on electrical conductivity is more complex and depends on the areas of overlap and in-plane contacts (type II). A higher type I area in comparison to type II implies an increase of electrical conductivity with overlapping whereas the opposite effect is found when type II area is higher than type I. The predicted results of the theoretical model fitted experimental measurements at different GNP contents and three roll milling processing conditions, giving a better overview of the influence of GNP geometry and interactions on electrical and thermal properties of nanocomposites.

Carbon nanotubes (CNT) were added to epoxy/polycaprolactone (PCL) blends in order to get electrically conductive blends. As it was expected, an increase of CNT content promotes a higher electrical conductivity due to the creation of more electrical pathways. Furthermore, it was observed that the enhancement is also observed with increasing PCL content, reaching values of around 0.2 S/m for 0.2 wt % CNT and 20 wt % PCL samples, due to its effect on rheological properties of the mixture, which affect positively to the CNT dispersion process, thus leading to more homogeneous and well dispersed nanocomposites, as observed by microstructural analysis. Thermal conductivity also increases with CNT content but decreases with PCL addition due to its insulating properties. A study of the voltage required to reach the above-mentioned self-healing temperature for each material has been performed by thermography monitoring. It has been observed that the samples with the highest amount of both CNT and PCL, have the best resistive heating capabilities due to a higher thermoresistive efficiency of the electrical network, reaching temperatures above 100 °C, at voltages below 150 V.