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Triboelectric nanogenerators (TENGs) are an attractive energy harvesting technology due to their high efficiency and vast applications in self-powered sensors. In this work, dielectric–dielectric contact-separation TENGs were modeled with time-dependent finite element simulations with the objective of improving TENG’s performance by enhancing the relative permittivity (εr).To achieve this, the chosen material (PDMS, εr=2.75) was doped with SrTiO3 (εr = 300) particles. The open-circuit voltage (VOC) and short-circuit current (ISC) remained constant as ϵr increased, as predicted by existent models, but in contradiction with available experimental data. Thus, we introduced a charge correction model relating ϵr and surface charge density, allowing us to observe an increase in TENG performance output (VOC and ISC). This work shows that finite element simulations are suitable for better understanding and optimizing TENGs’ performance.

The global environmental crisis necessitates reliable, sustainable, and safe energy storage solutions. The current systems are nearing their capacity limits due to the reliance on conventional liquid electrolytes, which are fraught with stability and safety concerns, prompting the exploration of solid-state electrolytes, which enable the integration of metal electrodes. Solid-state sodium-ion batteries emerge as an appealing option by leveraging the abundance, low cost, and sustainability of sodium. However, low ionic conductivity and high interfacial resistance currently prevent their widespread adoption. This study explores polyvinyl-based polymers as wetting agents for the NASICON-type NZSP (Na3Zr2Si2PO12) solid electrolyte, resulting in a combined system with enhanced ionic conductivity suitable for Na-ion solid-state full cells. Electrochemical impedance spectroscopy (EIS) performed on symmetric cells employing NZSP paired with different wetting agent compositions demonstrates a significant reduction in interfacial resistance with the use of poly(vinyl acetate)—(PVAc-) based polymers, achieving an impressive ionic conductivity of 1.31 mS cm−1 at room temperature, 63.8% higher than the pristine material, notably reaching 7.36 mS cm−1 at 90 °C. These results offer valuable insights into the potential of PVAc-based polymers for advancing high-performance solid-state sodium-ion batteries by reducing their total internal resistance.

Abstract The synchronisation of magnetic tunnel junctions in the high frequency domain has attracted significant interest in the context of novel computation paradigms, specifically neuromorphic spintronics and probabilistic computing. In this work, a design for the coupling and synchronization of spin torque vortex oscillators (STVOs) is implemented. The geometry comprises the fabrication of adjacent pairs of STVO nanopillars (MgO-based magnetic tunnel junctions), with an edge-to-edge distance down to 100 nm, together with individual top contacts that allow an independent electrical access to each device. In this geometry, the magneto-dipolar coupling promotes the synchronization of the two oscillators, at the same time as the access to the frequency and phase of each individual oscillator is possible. Both frequency and time domain measurements confirm a successful synchronization, with the coupling being controlled by the relative DC bias in each oscillator. As a proof-of-concept towards an oscillator-based Ising machine, it is also shown that the second harmonic injection locking of an STVO can be controlled by tuning the magneto-dipolar coupling to its correspondent STVO pair. These results represent a step forward for the implementation of magneto-dipolar coupled magnetic tunnel junctions, specifically in the field of unconventional computing hardware.

The brain presents impressive characteristics, like memory retention and learning capabilities at low energy consumption, making it the most efficient computational entity known. A promising candidate for the task of mimicking the brain is a new generation of devices showing resistive switching, a process that resembles the synaptic behavior, namely the liquid-based resistive-switching memory (LRSM). Here we present a two-terminal structure that works based on a solution of silver nitrate (AgNO3) and a silver (Ag) electrode. Furthermore, since the goal is to mimic the behavior of synapses, the dynamical properties of resistive switching, endurance and data retention were studied. Low operation power was further achieved (

Energy consumption for building cooling is directly related to incident solar radiation. Therefore, solutions of high reflectivity, while keeping color comfort, are being actively researched. Here, finite-difference time-domain (FDTD) simulations were used to investigate the influence of nanoparticle and core–shell additives on coating reflection and color. Different TiO2 and CuO nanoparticle mixings were tested, with relative concentrations varying from 0 to 20% of each on acrylic. The same compounds were used to define core–shells with a varied inner radius (0–30 nm) for both TiO2 and CuO as the core and shell. The numerical simulations demonstrate that mixing CuO with TiO2 enables dark colors while maintaining the overall reflectance. The reflectance results for the core–shell structure are comparable with those of the nanoparticles when CuO is the core, while a more pronounced color change is originated when CuO is the shell.

Abstract In this work, a new mechanism to combine a non-volatile behaviour with the spin diode detection of a vortex-based spin torque nano-oscillator (STVO) is presented. Experimentally, it is observed that the spin diode response of the oscillator depends on the vortex chirality. Consequently, fixing the frequency of the incoming signal and switching the vortex chirality results in a different rectified voltage. In this way, the chirality can be deterministically controlled via the application of electrical signals injected locally in the device, resulting in a non-volatile control of the output voltage for a given input frequency. Micromagnetic simulations corroborate the experimental results and show the main contribution of the Oersted field created by the input RF current density in defining two distinct spin diode detections for different chiralities. By using two non-identical STVOs, we show how these devices can be used as programmable non-volatile synapses in artificial neural networks.

Rechargeable sodium seawater batteries (SWBs) are gaining the world leadership of high voltage energy storage devices for marine environments. With natural seawater as the source of active material, SWBs can be supplied infinitely with Na cations. Because of their open-structured cathode, the cathode material’s specific surface area, porosity and wettability need to be optimized to achieve a high-performance cell. In this work, activated textile polyacrylonitrile (PAN) fibers were used to produce an activated carbon felt with a facile manufacturing process. The easy and low-cost production of these fibers makes them excellent candidates for energy storage applications involving oxygen evolution and reduction reactions. The electrochemical performance results of the fabricated activated PAN fibers and of commercial carbon felts were measured and compared, being characterized through galvanostic charge discharge cycles, electrochemical impedance spectroscopy and cyclic voltammetries. A performance improvement was observed with PAN activated carbon felt as half cell with a capacitance increase (about 9000%), and as full cell with a smaller voltage gap (about 10%) and increased gravimetric capacitance (about 260%) when compared to the commercial carbon felt. The successful implementation of PAN activated carbon felts in an aqueous environment opens new paths toward high performance seawater battery’s cathodes.

Enquadramento: a implementação do jejum pré-operatório tem sido uma preocupação mundial dos vários profissionais de saúde, havendo uma atuação distinta, no que concerne às orientações em vigor em cada uma das instituições. Objetivos: conhecer a evidência científica sobre as orientações atuais acerca da aplicação do jejum pré-operatório em clientes submetidos a cirurgia eletiva, publicada nos últimos cinco anos. Metodologia: estudo de revisão integrativa da literatura através das bases de dados SciELO, PubMedÒ, Academic Search Complete, CINAHLÒ, MedicLatina e MEDLINEÒ, com recurso aos descritores “fasting”, “preoperative care”, “patients” e “nursing”. Resultados: foram analisados dez artigos e os dados organizados em três macrocategorias: orientações sobre o jejum pré-operatório; ganhos inerentes à implementação das orientações atuais; e fatores dificultadores da implementação das orientações atuais sobre o jejum pré-operatório. Conclusão: as várias organizações que se debruçam sobre esta temática já evidenciaram guidelines norteadoras. Contudo nas instituições de saúde nem sempre se verifica a implementação destas orientações. O enfermeiro deverá consciencializar o cliente deste procedimento pré-operatório, assim como ser um agente de mudança no cumprimento deste procedimento.

Objective: To identify the most consensual conceptions of nursing, individuals, health and environment among the nurses specialists in rehabilitation nursing. Method: A quantitative, descriptive-exploratory study was carried out in 36 hospital institutions, and 306 specialist nurses were involved in this research. As a tool for data collection, it was performed a self-completion questionnaire. Results: Although there are differences in the five regions of the country, the nursing, individuals, health and environment conceptions that nurses in rehabilitation nursing designate as fully in accordance with their practice are those of Afaf Meleis, Dorothea Orem, Callista Roy and Madeleine Leininger. Conclusion: The congruence observed in the results regarding the different conceptions shows the consistency of the conceptual guidelines of the participants. In this sense, the challenge is to consolidate the support of the professional practice of nurses who are specialists in rehabilitation nursing in the theoretical frameworks whose conceptions are considered fully in accordance with their practice.

Objective: To understand the perception of nurses who are specialists in rehabilitation nursing, regarding the achievement of quality standards in the hospital context. Method: A quantitative, descriptive-exploratory study conducted in 36 hospital institutions, with the participation of 306 nurses. A self-filling questionnaire was used to collect data. Results: The majority of the participants always perform activities that contribute to quality of care. From the analysis performed, the activities of the dimensions of prevention of complications, wellbeing and self-care, functional readaptation and responsibility and rigor are those that the nurses perceive as more executed. On the other hand, the activities less concretized, refer to those included in the dimensions of customer satisfaction, organization of nursing care and, essentially, health promotion. Conclusion: The data made clear that the contribution of nurses specialists in rehabilitation nursing for quality of care is specifically focused on the descriptive statements well-being and selfcare and functional readaptation.

This study describes a new approach to explore the design of public open spaces based on a multidimensional analysis useful to inform decision-making and foster the development of evidence-based architectural solutions. It presents an overview of the most relevant design variables and their constraints, providing, in this way, valuable information for the elaboration of a more sustainable urban design, considerate of the local socio-cultural values. This research aims at providing holistic guidance for the development of better design proposals in contemporary urban environments. More specifically, it seeks to synchronously characterize urban spaces at a multi-scale and multidimensional level, both quantitatively and qualitatively, by collecting contributions from Space Syntax Theory, Public Life Studies, Building Science and Environmental/Comfort Analysis in public open spaces. Many advanced digital tools are used for data management purposes and to generate and test iteratively different design proposals. The proposed methodology is based on a range of tests and analyses performed in the process of developing a new experimental project for Largo da Graça, an urban square located in Lisbon’s historic centre, which allowed the testing of different design solutions. This experiment generated a digital workflow for the design of the urban square, in which are registered all the steps undertaken to solve the many design problems identified by considering the efficiency targets (centrality, connectivity, enclosure, thermal comfort, security, social equity and interaction). The process comprises a sequence of comparative design reviews and records the choices made when dealing with latent information underlying changing conditions in the use of public space and the programmatic malleability of the Portuguese plaza. The description of the adopted design strategy and the examples extracted from the workflow are used to illustrate the practical approach of the proposed methodology. Ultimately, this study seeks to show how tightening the link between applied research and sustainable urban design can effectively support the design and planning of better public open spaces.

Present computer processing capabilities are becoming a restriction to meet modern technological needs. Therefore, approaches beyond the von Neumann computational architecture are imperative and the brain operation and structure are truly attractive models. Memristors are characterized by a nonlinear relationship between current history and voltage and were shown to present properties resembling those of biological synapses. Here, the use of metal-insulator-metal-based memristive devices in neural networks capable of simulating the learning and adaptation features present in mammal brains is discussed.

The authors wish to add the following information to the acknowledgements section of their paper published in Nanomaterials [...]

Highly ordered anodic hafnium oxide (AHO) nanoporous or nanotubes were synthesized by electrochemical anodization of Hf foils. The growth of self-ordered AHO was investigated by optimizing a key electrochemical anodization parameter, the solvent-based electrolyte using: Ethylene glycol, dimethyl sulfoxide, formamide and N-methylformamide organic solvents. The electrolyte solvent is here shown to highly affect the morphological properties of the AHO, namely the self-ordering, growth rate and length. As a result, AHO nanoporous and nanotubes arrays were obtained, as well as other different shapes and morphologies, such as nanoneedles, nanoflakes and nanowires-agglomerations. The intrinsic chemical-physical properties of the electrolyte solvents (solvent type, dielectric constant and viscosity) are at the base of the properties that mainly affect the AHO morphology shape, growth rate, final thickness and porosity, for the same anodization voltage and time. We found that the interplay between the dielectric and viscosity constants of the solvent electrolyte is able to tailor the anodic oxide growth from continuous-to-nanoporous-to-nanotubes.

Astrocytes are neuroglial cells that exhibit functional electrical properties sensitive to neuronal activity and capable of modulating neurotransmission. Thus, electrophysiological recordings of astroglial activity are very attractive to study the dynamics of glial signaling. This contribution reports on the use of ultra-sensitive planar electrodes combined with low noise and low frequency amplifiers that enable the detection of extracellular signals produced by primary cultures of astrocytes isolated from mouse cerebral cortex. Recorded activity is characterized by spontaneous bursts comprised of discrete signals with pronounced changes on the signal rate and amplitude. Weak and sporadic signals become synchronized and evolve with time to higher amplitude signals with a quasi-periodic behavior, revealing a cooperative signaling process. The methodology presented herewith enables the study of ionic fluctuations of population of cells, complementing the single cells observation by calcium imaging as well as by patch-clamp techniques.

Among the different phases of complex design processes, early design is the most dynamic and unpredictable stage since it involves a great deal of uncertainty, concurrency of activity streams, collaborative design iterations, and distributed and adaptive decision-making behaviour in response to both organizational commitments and to the occurrence of unforeseen events. This paper argues that current activity-based modelling approaches have limited ability to capture the dynamics of complex early design processes and explores novel modelling approaches. The development of an Agent Model for Planning and rEsearch of eaRly dEsign (AMPERE) aiming to capture various facets of uncertainty, iteration, collaboration and adaptation is described. The model was developed to tackle early design phases of complex systems, with the ability to deal with changes in requirements coming in and affecting the subsequent design evolution while design tasks are on-going. Initial results from agent-based simulations are presented, showing how the agent-based approach can support industrial organizations evaluating likely early design project performance and understanding complex cause–effect relationships that may affect project outcomes. Early design planning support from the agent model is demonstrated through an investigation to the likely project performance for varying levels of externally driven requirements change.

With the consistent shrinking of devices, micro-systems are, nowadays, widely used in areas such as biomedics, electronics, automobiles, and measurement devices. As devices shrunk, so too did their energy consumptions, opening the way for the use of nanogenerators (NGs) as power sources. In particular, to harvest energy from an object’s motion (mechanical vibrations, torsional forces, or pressure), present NGs are mainly composed of piezoelectric materials in which, upon an applied compressive or strain force, an electrical field is produced that can be used to power a device. The focus of this work is to simulate the piezoelectric effect in different ZnO nanostructures to optimize the output potential generated by a nanodevice. In these simulations, cylindrical nanowires, nanomushrooms, and nanotrees were created, and the influence of the nanostructures’ shape on the output potential was studied as a function of applied parallel and perpendicular forces. The obtained results demonstrated that the output potential is linearly proportional to the applied force and that perpendicular forces are more efficient in all structures. However, nanotrees were found to have an increased sensitivity to parallel applied forces, which resulted in a large enhancement of the output efficiency. These results could then open a new path to increase the efficiency of piezoelectric nanogenerators.