1,720,965 research outputs found
Fully Textile X-Ray Detectors Based on Fabric-Embedded Perovskite Crystals
Full text linkThe interest and thrust for wearable ionizing radiation dosimeters are rapidly growing, stimulated by a large number of different applications impacting on humankind, spanning from medicine to civil security and space missions. Lead halide perovskites are considered one of the most promising classes of novel materials for X-ray detectors due to their superior electronic and detection performance coupled with compatibility with solution-based printing processes, allowing fabrication onto flexible substrates. It is reported on fully textile perovskite-based direct X-ray detectors, where the photoactive layer is constituted by a silk-satin fabric functionalized with methylammonium lead bromide perovskite crystals embedded in the textile. The reliability of the proposed fabrication process, based on simple and low-tech deposition techniques adaptable to industrial printing technologies for textiles, is assessed by realizing different detector's architectures that exhibit comparable detection performances. Sensitivity values up to (12.2 +/- 0.6) mu C Gy(-1) cm(-2) and a limit of detection down to 3 mu Gy s(-1) are achieved, and low bias operation (down to 1 V) is demonstrated, validating wearable applications. Further, fully textile pixelated matrix X-ray sensors are implemented and tested, providing the proof of principle for large-area scalability
Impact of Fabric Properties on Textile Pressure Sensors Performance
Full text linkAbstract: In recent years, wearable technologies have attracted great attention in physical and chemical sensing applications. Wearable pressure sensors with high sensitivity in low pressure range (<10 kPa) allow touch detection for human-computer interaction and the development of artificial hands for handling objects. Conversely, pressure sensors that perform in a high pressure range (up to 100 kPa), can be used to monitor the foot pressure distribution, the hand stress during movements of heavy weights or to evaluate the cyclist’s pressure pattern on a bicycle saddle. Recently, we developed a fully textile pressure sensor based on a conductive polymer, with simple fabrication and scalable features. In this paper, we intend to provide an extensive description on how the mechanical properties of several fabrics and different piezoresistive ink formulation may have an impact in the sensor’s response during a dynamic operation mode. These results highlight the complexity of the system due to the presence of various parameters such as the fabric used, the conductive polymer solution, the operation mode and the desired pressure range. Furthermore, this work can lead to a protocol for new improvements and optimizations useful for adapting textile pressure sensors to a large variety of applications
Design of an electrochemically gated organic semiconductor for pH sensing
Full text linkSince the development of potentiometric ion-selective electrodes, remarkable steps have been taken towards progressive simplification and improved robustness of pH sensing probes. In particular, the design of compact sensing architectures using solid-state components holds great potential for portable and wearable applications. Here we report the development of an electrochemically gated device for pH detection, combining the robustness of potentiometric-like transduction with an extremely simple and integrated geometry requiring no reference. The sensor is a two-point probe device comprising two thin polymeric films, i.e. a charge transport layer and a pH-sensitive layer, and exhibits a sensitivity of (8.3 ± 0.2) × 10−3 pH unit−1 in the pH range from 2 to 7. Thanks to the versatility and robustness of the optimised design, a textile pH sensor was fabricated whose performance is comparable with that of glass sensors
Adaptable pressure textile sensors based on a conductive polymer
No full textAbstract
Recent studies in the field of safety in the workplace have focused on developing new sensors and
procedures to detect and monitor body stress due to repeated or highly stressful movements that, in
the long term, could lead to painful traumas or accidents. Today, the common method used to
evaluate risk activities is based on evaluations that are subjective or supported by difficult and time-
consuming video analysis. However, recent developments in wearable sensors, in particular pressure
sensors, allow for innovative alternatives. The main requirements of wearable pressure sensors are
good wearability, allowing natural movements and a sensor response in a broad range of pressure to
allow a large variety of possible activities to be monitored. In this paper, we report on a new promising
class of textile pressure sensors based on the employment of a conductive polymer that can be easily
deposited directly on the fabric, for example, to fabricate sensorized gloves to monitor hand stress
during manual activity. The main advantages of the proposed technology comprise the possibility of
selectively tuning the pressure response range, adapting it to different applications by changing the
formulation of the conductive polymer while leaving the same device architecture and structures. We
deposit and characterize the active sensing layer, analyze the pressure sensor response and propose an
interpretation of the obtained results based on piezoresistive phenomena. We identify three different
contributions to the sensor output, related to the macroscale, microscale and nanoscale, respectively.
Finally, we describe the production of sensorized textile gloves with fully textile pressure sensors that
are comfortable, reproducible, low cost and easily tunable in pressure range response
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Wearable Electrochemical Gas Sensor for Ammonia Detection
No full textThe next future strategies for improved occupational safety and health management could largely benefit from wearable and Internet of Things technologies, enabling the real-time monitoring of health-related and environmental information to the wearer, to emergency responders, and to inspectors. The aim of this study is the development of a wearable gas sensor for the detection of NH3 at room temperature based on the organic semiconductor poly(3,4-ethylenedioxythiophene) (PEDOT), electrochemically deposited iridium oxide particles, and a hydrogel film. The hydrogel composition was finely optimised to obtain self-healing properties, as well as the desired porosity, adhesion to the substrate, and stability in humidity variations. Its chemical structure and morphology were characterised by infrared spectroscopy and scanning electron microscopy, respectively, and were found to play a key role in the transduction process and in the achievement of a reversible and selective response. The sensing properties rely on a potentiometric-like mechanism that significantly differs from most of the state-of-the-art NH3 gas sensors and provides superior robustness to the final device. Thanks to the reliability of the analytical response, the simple two-terminal configuration and the low power consumption, the PEDOT:PSS/IrOx Ps/hydrogel sensor was realised on a flexible plastic foil and successfully tested in a wearable configuration with wireless connectivity to a smartphone. The wearable sensor showed stability to mechanical deformations and good analytical performances, with a sensitivity of 60 ± 8 μA decade−1 in a wide concentration range (17–7899 ppm), which includes the safety limits set by law for NH3 exposure
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
