Current Issue : April - June Volume : 2019 Issue Number : 2 Articles : 5 Articles
A new interatomic potential for the pure tin (Sn) system is developed on the basis of the\nsecond-nearest-neighbor modified embedded-atom-method formalism. The potential parameters\nwere optimized based on the force-matching method utilizing the density functional theory (DFT)\ndatabase of energies and forces of atomic configurations under various conditions. The developed\npotential significantly improves the reproducibility of many fundamental physical properties\ncompared to previously reported modified embedded-atom method (MEAM) potentials, especially\nproperties of the....................
In this work, an algorithm was developed to measure respiration rate for an embedded\ndevice that can be used by a field robot for relief operations. With this algorithm, the rate measurement\nwas calculated based on direct influences of respiratory-induced intensity variation (RIIV) on\nblood flow in cardiovascular pathways. For this, a photoplethysmogram (PPG) sensor was used\nto determine changes in heartbeat frequencies. The PPG sensor readings were filtered using an\nInformation Filter and a fast Fourier transform (FFT) to determine the state of RIIV. With a relatively\nlight initialization, the information filter can estimate unknown variables based on a series of\nmeasurements containing noise and other inaccuracies. Therefore, this filter is suitable for application\nin an embedded device. For faster calculation time in the implementation, the FFT analysis was\ncalculated only for a major peak in frequency domain. Test and measurement of respiration rate\nwas conducted based on the device algorithm and spirometer. Heartbeat measurements were also\nevaluated by comparing the heartbeat data of the PPG sensor and pulse-oximeter. Based on the\ntest, the implemented algorithm can measure the respiration rate with approximately 80% accuracy\ncompared with the spirometer....
This research explores a new realm of soft robotic materials where the stiffness magnitude,\ndirectionality, and spatial resolution may be precisely controlled. These materials mimic biological\nsystems where localized muscle contractions and adjustment of tissue stiffness enables meticulous,\nintelligent movement. Here we propose the use of a low-melting-point (LMP) metal lattice structure\nas a rigid frame using localized heating to allow compliance about selectable axes along the lattice.\nThe resulting shape of the lattice is modeled using product of exponentials kinematics to describe the\nserial chain of tunably compliant axes; this model is found to match the behavior of the physical test\npiece consisting of a Fieldâ??s metal (FM) lattice encased in silicone rubber. This concept could enable\nhighly maneuverable robotic structures with significantly improved dexterity....
The principle of digital watermark is the method of adding digital watermark\nin the frequency domain. The digital watermark hides the watermark in digital\nmedia, such as image, voice, video, etc., so as to realize the functions of\ncopyright protection, and identity recognition. DCT for Discrete Cosine\nTransform is used to transform the image pixel value and the frequency domain\ncoefficient matrix to realize the embedding and extracting of the blind\nwatermark in the paper. After success, the image is attacked by white noise\nand Gaussian low-pass filtering. The result shows that the watermark signal\nembedded based on the DCT algorithm is relatively robust, and can effectively\nresist some attack methods that use signal distortion to destroy the watermark,\nand has good robustness and imperceptibility....
In the present work, we study the low velocity impact, both central and eccentric, on square\nand rectangular laminated composite plates with embedded shape memory alloy (SMA) wires,\nwhich are stitched on the top and bottom surfaces of the plate, by using the finite element method.\nIn finite element methods (FEM) simulations, a super-elastic SMA constitutive model is implemented\nin Abaqus/Explict by using a user defined material subroutine to describe the behaviors of SMAs.\nThe three-dimensional (3D) Hashin failure criterion is adopted to model the damage initiation of\nlaminated composite plates. To model the delamination failure, a cohesive damage zone model is\nintroduced in interface elements. A comprehensive parametric study has been carried out to analyze\nthe effects of eccentricity for the case of square and rectangular laminated composite plates....
Loading....