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•Nanocellulose-graphene-based materials used for supercapacitors are reviewed.•Design of different types of nanocellulose-graphene flexible supercapacitor electrode.•Broaden the ...application of nanocellulose-graphene in flexible energy storage devices.
With the increasing consumption of global fossil energy and environmental pollution, the development of green renewable energy and efficient energy storage technology become an urgent problem to solve. Supercapacitors have drawn a great interest for use in wearable electronic devices due to their portability and stable performance. The electrode is very important when preparing a high-performance flexible supercapacitor, which requires good electrochemical performance and flexibility. Graphene and nanocellulose are excellent flexible electrode material for supercapacitors, and nanocellulose is often used as a substrate material for electronic devices because of its good biodegradability, mechanical flexibility and chemical reactivity. In this work, the structure design and assembly method of the nanocellulose-graphene composite materials used for flexible supercapacitors are reviewed. The mechanical flexibility, specific capacitance, electrochemical performance, cyclic stability, renewability and biodegradability are taken into account, so as to evaluate the performance of the composite materials and to better assess the merits of this material with respect to real applications.
Objective. In electroencephalography (EEG) measurements, the signal of each recording electrode is contrasted with a reference electrode or a combination of electrodes. The estimation of a neutral ...reference is a long-standing issue in EEG data analysis, which has motivated the proposal of different re-referencing methods, among which linked-mastoid re-referencing (LMR), average re-referencing (AR) and reference electrode standardization technique (REST). In this study we quantitatively assessed the extent to which the use of a high-density montage and a realistic head model can impact on the optimal estimation of a neutral reference for EEG recordings. Approach. Using simulated recordings generated by projecting specific source activity over the sensors, we assessed to what extent AR, REST and LMR may distort the scalp topography. We examined the impact electrode coverage has on AR and REST, and how accurate the REST reconstruction is for realistic and less realistic (three-layer and single-layer spherical) head models, and with possible uncertainty in the electrode positions. We assessed LMR, AR and REST also in the presence of typical EEG artifacts that are mixed in the recordings. Finally, we applied them to real EEG data collected in a target detection experiment to corroborate our findings on simulated data. Main results. Both AR and REST have relatively low reconstruction errors compared to LMR, and that REST is less sensitive than AR and LMR to artifacts mixed in the EEG data. For both AR and REST, high electrode density yields low re-referencing reconstruction errors. A realistic head model is critical for REST, leading to a more accurate estimate of a neutral reference compared to spherical head models. With a low-density montage, REST shows a more reliable reconstruction than AR either with a realistic or a three-layer spherical head model. Conversely, with a high-density montage AR yields better results unless precise information on electrode positions is available. Significance. Our study is the first to quantitatively assess the performance of EEG re-referencing techniques in relation to the use of a high-density montage and a realistic head model. We hope our study will help researchers in the choice of the most effective re-referencing approach for their EEG studies.
Auxetic materials or structures, especially 3D cellular lattice architectures with negative Poisson's ratio (NPR) have attracted great attention due to their unprecedented mechanical behaviors and ...promising applications in recent years. Many 3D auxetic architected cellular materials have been manufactured and characterized with polymers and metals using additive manufacturing technology as well as some fibre reinforced polymers (FRP) composites via assembly method, however metal 3D printed auxetic structures with high-quality are rarely reported and FRP composites using assembly method contain a variety of defects which result in a knock-down effect on mechanical properties. Auxetic structures made from polymers are normally of low stiffness and strength and FRP composites are of low toughness and impact resistance, which causes limitations on their structural and functional applications. If rationally designed structures can be made from high-performance metal materials the specific stiffness and strength of which are much higher than polymers, their specific stiffness and strength can be significantly increased which will make them more suitable for various potential applications. This paper presents novel 3D double-U hierarchical structures (DUHs) based on double-V hierarchical structures (DVHs) with tunable Poisson's ratio and Young's modulus by tailoring the geometry parameters. Experimental, numerical and theoretical results show that DUHs have smooth geometry that can reduce manufacturing damage and stress concentration under elastic loading. Another advantage of DUHs is that the curved configurations have enhanced auxetic behavior and higher static collapse stress than DVHs under crushing. The advanced 3D printing technology and those excellent mechanical properties of 3D DUHs meet the requirements of structural and functional applications.
No studies have examined the effects of fronto-temporal transcranial direct current stimulation (tDCS) on cognitive insight and neurocognitive function in schizophrenia patients and the dynamic ...interplay between tDCS-induced changes in these two outcomes. In this double-blind, randomized, sham-controlled study, we investigated the effects of fronto-temporal tDCS anode corresponding to left dorsolateral prefrontal cortex and cathode to left temporo-parietal junction; 2-mA, twice-daily sessions for 5 days on illness severity, psychosocial functioning, cognitive insight and neurocognitive function in schizophrenia patients (N = 60).
The authors observed significant trends that tDCS ameliorated the severity of total and general psychopathology as measured by the Positive and Negative Syndrome Scale. No significant effects were observed for other psychopathological symptoms and psychosocial functioning. Cognitive insight as measured by the Beck Cognitive Insight Scale (BCIS) was rapidly enhanced by 10-session tDCS (F = 10.80, Cohen's d = 0.44, p = 0.002) but the beneficial effect became borderline significant 1 month after stimulation. A trend-level improvement with tDCS of planning ability (F = 6.40, Cohen's d = 0.339, p = 0.014) as measured by the accuracy in Tower of London task was also observed. In the active tDCS group, the change in cognitive insight from baseline to immediately after tDCS assessment was positively correlated with that in planning ability (r = 0.46, p = 0.015), which was independent of the corresponding change in illness severity. The promising results regarding the fast-acting beneficial effects of tDCS on cognitive insight and planning ability in schizophrenia require confirmation in future replication studies.
With its creation of fissures and fragments, the montage is uniquely positioned to question the representational power of architecture. When related to the field of preservation such a gesture ...conflicts with preservation’s traditional urge to reinstall and complete the architectural fragment into a grander narrative and its underlying leitmotif of authenticity and integrity. From an analysis of Alex Lehnerer’s and Savvas Ciriacidis’s installation Bungalow Germania, the paper explores the possibility of an experimental and critical notion of preservation. A notion emerging from the artistic strategy of montage which frames the fragment as productive rather than reductive. With that, preservation might become a creative just as much as restorative field of practice.
La apuesta benjaminiana implica repensar la historia de forma tal que al contarla no se dé nada por perdido. De aquí la necesidad de un nuevo método histórico que capte críticamente desde el presente ...los materiales del pasado para, así, actualizarlos. En el presente artículo, partimos del poemario argentino Deuda & literatura, de Omar Chauvié (2017), para llevar a cabo una reflexión sobre el montaje como principio técnico y metodológico de construcción del conocimiento histórico. En segundo lugar, haremos un recorrido por el concepto de montaje y de ciertas figuras —la técnica, la cita, lo auténtico— para ver cómo operan en las diversas esferas de pensamiento de Walter Benjamin. Por último, abordaremos la idea de historia discontinua benjaminiana y la noción de anacronismo. Este recorrido nos permitirá vislumbrar que es posible otra construcción del conocimiento histórico a partir de la cita de materiales y de la estructura de un montaje que lleve como insignia y sello lo “auténtico”.
Miklós Erdély (1928-1986), an exceptional artist in the international and Hungarian scene, created the work that serves as the basis of this analysis in 1976. Man is Not Perfect – the title refers to ...Karl Jaspers – consists of four panels. In its current state, the work bears little resemblance to what spectators saw in 1976 in the event Exposition - photo/art, for which the work was made. The changes in the visibility, what we can see in the reproductions from different periods, were “pre-programmed”, if we may say so, into the materiality of the work by the author, as Erdély was always especially conscious of the use of materials. Does this transformation in time change the meaning of the artwork, and if so, why and how? The relations between the diverse elements or “medium” of the montage, like original photographs, reproductions, blueprints, citations, ready-made parts, photograms and phantom images, may explain the “story” in a pictorial way.
The number of electrodes used to acquire neonatal EEG signals varies between institutions. Therefore, tools for automatic EEG analysis, such as neonatal seizure detection algorithms, need to be able ...to handle different electrode montages in order to find widespread use. The aim of this study was to analyse the effect of montage on neonatal seizure detector performance. A full 18-channel montage was compared to reduced 3- and 8-channel montages using a convolutional neural network for seizure detection. Sensitivity decreased by 10 - 18 % for the reduced montages while specificity was mostly unaffected. Electrode artefacts and artefacts associated with biological rhythms caused incorrect classification of nonseizure activity in some cases, but these artefacts were filtered out in the 3-channel montage. Other types of artefacts had little effect. Reduced montages result in some reduction in classifier accuracy, but the performance may still be acceptable. Recording artefacts had a limited effect on detection accuracy.
Electroencephalography (EEG) is the most commonly used functional investigative method in epilepsy. The goal of this educational review paper is to summarize the most important aspects related to the ...biophysical phenomena of EEG signal generation and the technical features that a clinician needs to understand in order to read and interpret EEGs. We explain the EEG electrodes and recording arrays, amplifiers, filters, analogue‐to‐digital conversion and signal display. We describe the advantages and disadvantages of the different montages and the indications for the various types of EEG recordings and provocative maneuvers. We explain how to use topographic maps to estimate the source of the cortical generator.
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Ever since the Victorian era, montage, the process of pictorial composition made by juxtaposing or superimposing photographs, has been a very popular post-editing imaging technique. ...Despite showing a strong power in demonstrating complex wave field effects, this technique has neither been fully explored in acoustic imaging nor been realized in real-time systems with the capability beyond diffraction limits. On the other hand, the recent prospect of metamaterials has shown their great potentials in super-resolution acoustic imaging. However, the miracle jigsaw of more advanced functional modulation of acoustic wave fields at deep subwavelength scale still remains elusive. Here we report the experimental implementation of super-resolution acoustic image montage through a judiciously designed biaxial metamaterial lens. Based on the non-diffraction birefringence in the biaxial metamaterials, we realized various montage functionalities such as duplication, composition, and decomposition of sound images with distinctive deep subwavelength features. Our work represents an important step in developing versatile functional acoustic metamaterial devices for imaging purposes, as it provides on-demand editing of sound field patterns beyond diffraction limits.
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