1,720,982 research outputs found
Performance analysis based on biomolecule position and pH-sensing mechanism for vertical TFET
No full textIn this study, the impact of the diffusion mechanism of a biomolecule in the nanocavity ( Tbio ) region on the electrical characteristics of a split-gate, step-channel electrolyte-insulated semiconductor vertical TFET (SGSC-EIS-VTFET) pH biosensor was investigated. The impact of the transport sensing mechanism, that is, diffusion-limited process and rapid mixing process of biomolecules in the nanocavity sensing area, on the pH of the analyte was also examined. Physics-based modelling was used to determine the interface charge density at the oxide-silicon interface of the proposed vertical TFET pH biosensor. We also considered the effect of pH values on the proposed device performance, like drain current (Ids), transconductance (gm), current sensitivity (SID), and voltage sensitivity (SV) after the inclusion of electrolyte medium. Here, the maximum SV similar to 145 mH pH-1 for Tbio = 6 nm, which is higher than the Nernstian limit (59.2 mV pH-1), and SID has been enhanced by 10 times per pH variation. This study indicated that the diffusion of biomolecules significantly impacts the performance parameters of the proposed structure because of the realistic dominance of the sensing mechanism and the conjugation of analyte on the sensing area
Design and Simulation Analysis of Electrolyte-Gated Aluminum Oxide Organic Thin-Film Transistor Biosensor for High Sensitivity
No full textIn this article, an electrolyte-gated aluminum oxide thin film transistor with a pentacene structure has been developed as an effective pH sensor. It has a high sensitivity, low power consumption, and low pH resolution. Electrolyte-gated organic semiconductor materials improve the performance of pentacene-based pH sensors. Aluminum oxide is an insulation material for organic semiconductors in the proposed structure. OTFT's current sensitivity was determined using a 2D transport charge model, which provided physical insight into electrolyte transport. Atlas TCAD simulation tool was used to calculate voltage and drain current sensitivity to Al2O3. The proposed architecture achieved a voltage sensitivity of 255.9 mV/pH, four times greater than the Nernst limit. The pH sensor is suitable for various applications due to its high sensitivity and low power consumption. As a result, it can be used in environmental monitoring to detect changes in water quality, in healthcare to monitor pH levels in bodily fluids, or in industrial processes to ensure optimal pH levels during chemical reactions
Nanogenerators for human body energy harvesting
Full text linkHumans generate remarkable quantities of energy while performing daily activities, but this energy usually dissipates into the environment. Here, we address recent progress in the development of nanogenerators (NGs): devices that are able to harvest such body-produced biomechanical and thermal energies by exploiting piezoelectric, triboelectric, and thermoelectric physical effects. In designing NGs, the end-user's comfort is a primary concern. Therefore, we focus on recently developed materials giving flexibility and stretchability to NGs. In addition, we summarize common fabrics for NG design. Finally, the mid-2020s market forecasts for these promising technologies highlight the potential for the commercialization of NGs because they may help contribute to the route of innovation for developing self-powered systems. The human body produces a huge amount of energy while performing daily activities. Harvesting this energy could represent a turning point for powering wearable devices.Advances in physical and chemical fields enable the design of flexible and stretchable materials that adhere to the surface of the body to follow the shape of the skin.Functional polymeric fibers allow the development of smart-clothes for harvesting the energy on the surface of the human body
A new microcontroller-based system to optimize the digital conversion of signals originating from load cells built-in into pedals
No full textDuring cycling, the measurement of forces exerted on the pedal is used to monitor the level of training and to maximize the efficiency of pedaling. In rehabilitation, the force measurement can be used to monitor the functional recovery of a patient during a therapy. In these situations, it is useful to quantify with high resolution these variables. In this work a solution to remove the DC offset at the input of an AD converter for force measurement systems, based on strain gauges load cells, is presented. This circuit has been integrated into a device used in sports and in rehabilitation contexts, that relies on a couple of cycling instrumented pedals. The system designed in this work aims at obtaining these results in a simple way and with its complete integration into the control circuit of the instrumented pedals
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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Using PVDF films as flexible piezoelectric generators for biomechanical energy harvesting
Full text linkIn this paper, a commercial polymeric piezoelectric film, the polyvinylidene fluoride (PVDF) was used to harvest electrical energy during the execution of five locomotion activities (walking, going down and up the stairs, jogging and running). The PVDF film transducer was placed into a tight suit in proximity of four body joints (shoulder, elbow, knee and ankle). The RMS values of the power output measured during the five activities were in the range 0.1-10 Î1⁄4W depending on the position of the film transducer on the body. This amount of electrical power allows increasing the operation time of wearable systems, and it may be used to prolong the monitoring of human vital signals for personalized health, wellness, and safety applications
A Framework Integrating Augmented Reality and Wearable Sensors for the Autonomous Execution of Rehabilitation Exercises
No full textDespite the resolution of pathology at admission, many hospitalized patients are discharged in a worse functional state, particularly in terms of walking capabilities, due to hospitalization inactivity. Early interventions to maintain the functional state through exercise such as passive mobilization, executed during hospitalization, have been proven to be effective in preventing physical and cognitive decline. Unfortunately, many patients can be excluded from such treatments due to the high number of people hospitalized and the limited availability of healthcare personnel. This paper presents a framework that allows the patient to autonomously perform the exercises without the assistance of qualified personnel. Such a framework exploits the advantages of an Augmented Reality (AR) device in which the patient can visualize real-time instructions on the exercises and directions on their execution. The monitoring of the patient’s movements during exercise is accomplished by means of dedicated wearable sensors fixed to the patient’s limb. The system was tested in preliminary experiments on healthy people
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