1,720,970 research outputs found
Uncertainty Sources in Aerosol Jet Printed and Flexible Electrochemical Sensors
No full textElectrochemical sensors are nowadays used in a wide set of applications even though they still present major issues that weaken their metrological characteristics. Among those, noise is interesting because determines the lowest detectable concentration and allows developing better models for electrochemical sensors. In this work, a set of flexible electrochemical sensors produced by Aerosol Jet Printing (AJP) are analyzed to identify their different noise and uncertainty sources. Different conditions such as analyte concentration variations and temperature fluctuations are taken into consideration. Effects on noise of processes inherently connected with the transduction principle such as double-layer capacitance and mass transport were observed as well as a correlation between the analyte concentration and the overall noise. Thermal effects analysis revealed an overall increment of the noise level up to 52.4% in a 10°C interval while a variation of over 100% of the mean output current on the same interval are recorded. According to the results presented in this work, noise and temperature effects should be taken into consideration in the design of novel electrochemical devices to improve their reliability in uncontrolled conditions
A Preliminary Study on Flexible Temperature Sensors for Eskin Medical Devices
Full text linkIn the latest years, the need of a renewed paradigm for healthcare arose promoting the research towards the idea of remote diagnosis, care and monitoring of physiological parameters. Thus, the wearable and eskin devices arose to be embedded in the standard medical equipment. In this work, a preliminary study on flexible AJP-printed temperature sensors is reported in order to propose a novel approach to evaluate infection sites, monitor the body temperature and compensate the effects of temperature on other on-body sensors. Two different geometries are proposed, designed, produced, evaluated and compared. The results shown a similar dependance on temperature (average TCR = 2.5 ∙ 10 -3 °C-1) and the dependance on substrate deformation was enquired as well as the geometrical features of the sensors
Preliminary Results on Carbon-Based Thermistors Produced by Aerosol Jet Printing
No full textElectronics became pervasive in the production sites generating the now-occurring fourth industrial revolution. In this paradigm, different information technologies are employed in order to achieve better control over the overall production process and better plan each maintenance intervention. In the monitoring processes, different physical quantities are constantly monitored with sensors connected to the acquisition electronics and therefore to the communication network. Among those, temperature sensors are relevant since they can provide a set of information useful to track the production process and the workers' wellbeing, and to compensate for the output of other sensors. Thus, in this work, the behavior of a carbon-based ink on different substrates was evaluated to produce thermistors. The devices were evaluated using both an oven and a climatic chamber and both positive (PTC) and negative (NTC) temperature coefficients were observed. The devices resulted promising with sensitivities comparable with the ones of standard Pt100 sensors in selected parts of the temperature measurement range
Preliminary Results on Fully-Printed and Silver-Based Temperature Sensors for Aerospace Industry
No full textNovel Piezoelectric Sensor by Aerosol Jet Printing in Industry 4.0
No full textIn the latest years, Industry 4.0 paradigm is leading to a reduction of industrial process tolerances, an increase in machine lifetime and an improvement of the quality of the products. The fundamental concept of this fourth industrial revolution is the data coming from the whole production process. Information is usually extracted by algorithms that work on a large amount of data that are collected on the field by a huge set of sensors. New, customized and cheap sensors that are integrated into objects and processes are required. In this work, we propose a method that allows producing a novel class of piezoelectric force sensors through an additive and novel printing method: Aerosol Jet Printing. This technology allows fabricating electronic components and sensors on a wide set of substrates also directly on the surface of the objects. Therefore, smart objects for Industry 4.0 can be designed and manufactured. With the proposed approach it was possible to fabricate both axial and shear force sensors with a d33 up to 101 mathrm{nC}cdot mathrm{N}^{-1} with a capacitance of 10.4 pF. The fabricated sensors are approximately 300mu mathrm{m} thick and can be shaped to fit different custom application requirements
Preliminary study of a sensorized system for real-time feedback for arachnoid collapse during neurosurgical training
No full textThe transsphenoidal surgery approach is a new minimally invasive procedure used by neurosurgeons to treat pituitary adenomas. One of the most challenging aspects of the surgery is handling the arachnoid membrane when it starts collapsing, as it is a thin and fragile membrane that contains the cerebrospinal fluid (CSF). 3D-printed training models do not provide a system capable of mimicking the arachnoid collapse during surgery. This work reports the results of two tests on a specifically designed system capable of reproducing the arachnoid and the CSF within. The system consists of a jar filled with distilled water and sealed with a food film and a screw cap. In addition, a pressure sensor is inserted into the system to measure the change in pressure generated by an indenter connected to a load cell. The idea is to correlate the indentation force with the pressure variation. Data show a promising result in both tests, with a evident correlation between force and pressure. The first test shows a linear trend, with an R2 = 0.984 for the loading phase and a R2 = 0.999 for the unloading phase. The second test shows a linear trend with R2 = 0.954 from the unloading phase, while as for the loading phase, it has a nonlinear trend for values of applied force less than 1 N, which then tends to a linear trend above this value, with an R2 = 0.996. However, there is a low repeatability when comparing one test with another due to the initial conditions of the food film, residual stresses and deformations once positioned on the top of the jar and closed by the cap, and probable pressure losses in the system
Nano-Functionalized Electrochemical Sensors by Aerosol Jet Printing
No full textIn the latest years, hydrogen peroxide quantification gained a growing interest in many fields both in industry and in the clinical environment. Among the different available methods, electrochemical transducers are of particular interest thanks to their ease of fabrication, convenient integration with microfluidics and electronics and their time and cost-effectiveness. Despite these advantages, electrochemical transducers are affected by many metrological issues. In this work, the novel technique of Aerosol jet printing (AJP) is exploited to fabricate fully printed nanostructured electrochemical sensors for hydrogen peroxide detection. Two different carbon-based printable nanostructures, carbon nanotubes (CNTs) and graphene, are employed to conveniently modify with the same technique electrodes' surfaces. The performances of the proposed design, production process and the different functionalization are explored and discussed. After a preliminary evaluation of the electrochemical characteristics of the printed devices, tests in hydrogen peroxide are carried on. Both materials present a limit of detections (LODs) and sensitivity comparable with the ones obtained in the literature, even though CNT better performs than graphene in terms of sensitivity (20 versus 2.8 mu mM(-2)). The latter presents however a signal-to-noise ratio (SNR) of 51.2 dB that outperforms the one of CNT (26.5 dB) and thus it has a better resistance against noise. Overall, both the evaluated nanostructures appear suitable to improve the metrological characteristics of printed electrochemical sensors and ease their spreading as environmental control devices, and diagnostic tools and assess quality in the industrial environment
3d electrochemical sensor and microstructuration using aerosol jet printing
Full text linkElectrochemical sensors are attracting great interest for their different applications. To improve their performances, basic research focuses on two main issues: improve their metrological characteristics (e.g., repeatability, reusability and sensitivity) and investigate innovative fabrication processes. In this work, we demonstrate an innovative microstructuration technique aimed at increasing electrochemical sensor sensitivity to improve electrode active area by an innovative fabrication technique. The process is empowered by aerosol jet printing (AJP), an additive-manufacturing and non-contact printing technique that allows depositing functional inks in precise patterns such as parallel lines and grids. The 3D printed microstructures increased the active surface area by up to 130% without changing the substrate occupancy. Further, electrochemical detection of ferro/ferri-cyanide was used to evaluate the sensitivity of the electrodes. This evaluation points out a sensitivity increase of 2.3-fold on average between bare and fully microstructured devices. The increase of surface area and sensitivity are well linearly correlated as expected, verifying the fitness of our production process. The proposed microstructuration is a viable solution for many applications that requires high sensitivity, and the proposed technique, since it does not require masks or complex procedures, turns out to be flexible and applicable to infinite construction geometries
Preliminary Study on a 3D Printed Sensorized Probe to Characterize Pituitary Adenoma Hardness
No full textEndoscopic endonasal transsphenoidal surgery approach, is a new surgical technique used by otolaryngologists and neurosurgeons to resect pituitary adenoma (PA). The most challenging aspect is related to the fact that the strategy of the resection changes according to the hardness of PAs, which is mostly soft, but it can also be harder (fibrous adenoma). This work proposes a first attempt to develop an alternative and innovative sensorized probe capable to discern the different hardness of soft materials. The proposed solution can be implemented in training models in order to give feedback to the users. The probe was developed thanks to additive manufacturing Fused Filament Fabrication (FFF) technology. Inside the probe there is a magneto resistive sensor and a magnet that is glued on the tip in order to measure the variation of the magnetic field linked to the movement of the magnet. After a preliminary electrically characterization of the probe, tests were conducted with three different silicones with slightly different Shore A attested hardness in order to verify if the probe is able to discern the materials. The first results show a high repeatability with a mean variation < 1%. Future work will be conducted with ex-vivo samples of pituitary adenomas in order to characterize their hardness and to classify the different types of PAs with a hardness parameter, and also to find the best material to mimic the consistency for training models
Novel Wearable System for Surface EMG Using Compact Electronic Board and Printed Matrix of Electrodes
No full textIn recent years, the application of IoT for health purposes, including the intense use of wearable devices, has been considerably growing. Among the wearable devices, the systems for measuring EMG (electromyography) signals are highly investigated. The possibility of recording different signals in a multichannel approach can lead to reliable data that can be used to improve diagnostic techniques, analyze performance in sports professionals and perform remote rehabilitation. In this work, we describe the design of a novel wearable system for surface EMG using a compact electronic board and a printed matrix of electrodes. The whole system has an estimated maximum current absorption of 55 mA at 3.3 V. We focused on the subsystem integration and on the real-time data transmission through Bluetooth Low Energy (BLE) with a throughput of 28 kB/s with a success rate of 99%. Some preliminary data are collected on a healthy man’s arm to validate the design. The acquired data are then analyzed and processed to improve information quality and extract contraction patterns
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