RIED. Revista iberoamericana de educación a distancia

Resumen basado en el de la publicaciónTítulo, resumen y palabras clave también en inglésMonográfico con el título: “La integración efectiva del dispositivo móvil en la educación y en el aprendizaje"Se plantea el debate sobre las innovaciones y tecnologías disruptivas, proponiendo que el aprendizaje digital (nueva versión de la educación a distancia) está suponiendo una disrupción educativa porque plantea un cambio drástico de soportes y métodos y porque progresivamente va ganando espacio a los formatos convencionales. Se concluye afirmando que esta tendencia no está agotada, sino que continúa penetrando y ahondando la ruptura con las nuevas tecnologías, como, por ejemplo, las analíticas de aprendizaje, el aprendizaje adaptativo y el aprendizaje móvil.ES

Carbon nanotube electroactive polymer materials: opportunities and challenges

Carbon nanotubes (CNTs) with macroscopically ordered structures (e.g., aligned or patterned mats, fibers, and sheets) and associated large surface areas have proven promising as new CNT electroactive polymer materials (CNT-EAPs) for the development of advanced chemical and biological sensors. The functionalization of CNTs with many biological species to gain specific surface characteristics and to facilitate electron transfer to and from them for chemical- and bio-sensing applications is an area of intense research activity. Mechanical actuation generated by CNT-EAPs is another exciting electroactive function provided by these versatile materials. Controlled mechanical deformation for actuation has been demonstrated in CNT mats, fibers, sheets, and individual nanotubes. This article summarizes the current status and technological challenges for the development of electrochemical sensors and electromechanical actuators based on carbon nanotube electroactive materials

One-step coating of fluoro-containing silica nanoparticles for universal generation of surface superhydrophobicity

Stable superhydrophobic surfaces with water contact angles over 170 degrees and sliding angles below 7 degrees were produced by simply coating a particulate silica sol solution of co-hydrolysed TEOS/fluorinated alkyl silane with NH3.H2O on various substrates, including textile fabrics (e.g. polyester, wool and cotton), electrospun nanofibre mats, filter papers, glass slides, and silicon wafers.<br /

Preparation of Monolayer MoS\u3csub\u3e2\u3c/sub\u3e Quantum Dots using Temporally Shaped Femtosecond Laser Ablation of Bulk MoS\u3csub\u3e2\u3c/sub\u3e Targets in Water

Zero-dimensional MoS2 quantum dots (QDs) possess distinct physical and chemical properties, which have garnered them considerable attention and facilitates their use in a broad range of applications. In this study, we prepared monolayer MoS2 QDs using temporally shaped femtosecond laser ablation of bulk MoS2 targets in water. The morphology, crystal structures, chemical, and optical properties of the MoS2 QDs were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis absorption spectra, and photoluminescence spectra. The analysis results show that highly pure, uniform, and monolayer MoS2 QDs can be successfully prepared. Moreover, by temporally shaping a conventional single pulse into a two-subpulse train, the production rate of MoS2 nanomaterials (including nanosheets, nanoparticles, and QDs) and the ratio of small size MoS2 QDs can be substantially improved. The underlying mechanism is a combination of multilevel photoexfoliation of monolayer MoS2 and water photoionization–enhanced light absorption. The as-prepared MoS2 QDs exhibit excellent electrocatalytic activity for hydrogen evolution reactions because of the abundant active edge sites, high specific surface area, and excellent electrical conductivity. Thus, this study provides a simple and green alternative strategy for the preparation of monolayer QDs of transition metal dichalcogenides or other layered materials

Integrated radiative and evaporative cooling beyond daytime passive cooling power limit

Radiative cooling technologies can passively gain lower temperature than that of ambient surroundings without consuming electricity, which has emerged as potential alternatives to traditional cooling methods. However, the limitations in daytime radiation intensity with a net cooling power of less than 150 W·m−2 have hindered progress toward commercial practicality. Here, we report an integrated radiative and evaporative chiller (IREC) based on polyacrylamide hydrogels combined with an upper layer of breathable poly(vinylidene fluoride-co-trifluoroethylene) fibers, which achieves a record high practical average daytime cooling power of 710 W·m−2. The breathable fiber layer has an average emissivity of over 76% in the atmospheric window, while reflecting 90% of visible light. This IREC possesses effective daytime radiative cooling while simultaneously ensuring evaporative cooling capability, enhancing daytime passive cooling effectively. As a result, IREC presents the practicability for both personal cooling managements and industrial auxiliary cooling applications. An IREC-based patch can assist in cooling human body by 13 °C low for a long term and biocompatible use, and IREC can maintain the temperature of industrial storage facilities such as oil tanks at room temperature even under strong sunlight irradiation. This work delivers the highest performance daytime passive cooling by simultaneous infrared radiation and water evaporation, and provides a new perspective for developing highly efficient, scalable, and affordable passive cooling strategy

Unraveling the Charge Storage Mechanism of Ti3C2Tx MXene Electrode in Acidic Electrolyte

Two-dimensional Ti3C2Tx MXenes have been extensively studied as pseudocapacitive electrode materials. This Letter aims at providing further insights into the charge storage mechanism of the Ti3C2Tx MXene electrode in the acidic electrolyte by combining experimental and simulation approaches. Our results show that the presence of H2O molecules between the MXene layers plays a critical role in the pseudocapacitive behavior, providing a pathway for proton transport to activate the redox reaction of the Ti atoms. Also, thermal annealing of the samples at different temperatures suggests that the presence of the confined H2O molecules is mainly controlled by the surface termination groups. These findings pave the way for alternative strategies to enhance the high-rate performance of MXenes electrodes by optimizing their surface termination groups