Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
By combining particle swarm optimization (PSO) and genetic algorithms (GA) this paper offers an innovative algorithm to\ntrain artificial neural networks (ANNs) for the purpose of calculating the experimental growth parameters of CNTs. The paper\nexplores experimentally obtaining data to train ANNs, as a method to reduce simulation time while ensuring the precision of\nformal physics models. The results are compared with conventional particle swarmoptimization based neural network (CPSONN)\nand Levenbergââ?¬â??Marquardt (LM) techniques. The results show that PSOGANN can be successfully utilized for modeling the\nexperimental parameters that are critical for the growth of CNTs....
This paper presents a highly sensitive flow-rate sensor with carbon nanotubes (CNTs)\nas sensing elements. The sensor uses micro-size centimeters long double-walled CNT (DWCNT)\nstrands as hot-wires to sense fluid velocity. In the theoretical analysis, the sensitivity of the sensor\nis demonstrated to be positively related to the ratio of its surface. We assemble the flow sensor by\nsuspending the DWCNT strand directly on two tungsten prongs and dripping a small amount of\nsilver glue onto each contact between the DWCNT and the prongs. The DWCNT exhibits a positive\nTCR of 1980 ppm/K. The self-heating effect on the DWCNT was observed while constant current\nwas applied between the two prongs. This sensor can evidently respond to flow rate, and requires\nonly several milliwatts to operate. We have, thus far, demonstrated that the CNT-based flow sensor\nhas better sensitivity than the Pt-coated DWCNT sensor....
The elbow joint is a complex articulation composed of the humeroulnar and humeroradial joints (for flexion-extension movement)\nand the proximal radioulnar articulation (for pronation-supination movement). During the flexion-extension movement of the\nelbow joint, the rotation center changes and this articulation cannot be truly represented as a simple hinge joint. The main goal\nof this project is to design and assemble a medical rehabilitation exoskeleton for the elbow with one degree of freedom for\nflexion-extension, using the rotation center for proper patient elbow joint articulation. Compared with the current solutions,\nwhich align the exoskeleton axis with the elbow axis, this offers an ergonomic physical human-robot interface with a\ncomfortable interaction. The exoskeleton is actuated with shape memory alloy wire-based actuators having minimum rigid\nparts, for guiding the actuators. Thanks to this unusual actuation system, the proposed exoskeleton is lightweight and has low\nnoise in operation with a simple design 3D-printed structure. Using this exoskeleton, these advantages will improve the medical\nrehabilitation process of patients that suffered stroke and will influence how their lifestyle will change to recover from these\ndiseases and improve their ability with activities of daily living, thanks to brain plasticity. The exoskeleton can also be used to\nevaluate the real status of a patient, with stroke and even spinal cord injury, thanks to an elbow movement analysis....
Nanowire-based field-effect transistors (FETs) have demonstrated considerable promise for\na new generation of chemical and biological sensors. Indium arsenide (InAs), by virtue of its high\nelectron mobility and intrinsic surface accumulation layer of electrons, holds properties beneficial for\ncreating high performance sensors that can be used in applications such as point-of-care testing for\npatients diagnosed with chronic diseases. Here, we propose devices based on a parallel configuration\nof InAs nanowires and investigate sensor responses from measurements of conductance over time\nand FET characteristics. The devices were tested in controlled concentrations of vapour containing\nacetic acid, 2-butanone and methanol. After adsorption of analyte molecules, trends in the transient\ncurrent and transfer curves are correlated with the nature of the surface interaction. Specifically,\nwe observed proportionality between acetic acid concentration and relative conductance change,\noff current and surface charge density extracted from subthreshold behaviour. We suggest the origin\nof the sensing response to acetic acid as a two-part, reversible acid-base and redox reaction between\nacetic acid, InAs and its native oxide that forms slow, donor-like states at the nanowire surface.\nWe further describe a simple model that is able to distinguish the occurrence of physical versus\nchemical adsorption by comparing the values of the extracted surface charge density. These studies\ndemonstrate that InAs nanowires can produce a multitude of sensor responses for the purpose of\ndeveloping next generation, multi-dimensional sensor applications...
We report a deposition of the tin oxide/hydroxide nanostructured layer by the potentiodynamic\nmethod from acidic nitrate solutions directly over the substrate, equipped with multiple strip electrodes\nwhich is employed as a gas-analytical multisensor array chip. The electrochemical synthesis is set to favor\nthe growth of the tin oxide/hydroxide phase, while the appearance of metallic Sn is suppressed by cycling.\nThe as-synthesized tin oxide/hydroxide layer is characterized by mesoporous morphology with grains,\n250ââ?¬â??300 nm diameter, which are further crystallized into fine SnO2 poly-nanocrystals following heating\nto 300 ââ??¦C for 24 h just on the chip. The fabricated layer exhibits chemiresistive properties under exposure\nto organic vapors, which allows the generation of a multisensor vector signal capable of selectively\ndistinguishing various vapors....
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