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In this study, we propose an optimized NRUS measuring and data processing protocol dedicated to small bone samples specially designed to be used in a four-point bending mechanical fatigue test. Our goal was to assess the elastic and dissipative hysteretic nonlinear parameters repeatability with the proposed protocol using several classes of materials with weak, intermediate and high nonlinear properties...
Multiple modes excited in a single solidly-mounted ZnO bulk acoustic resonator would provide a multi-band resonator operating at non-harmonically-related frequencies in the GHz range. Ordinarily, separate devices with different electrode and reflector designs are needed to excite the thickness shear (TSM) and thickness-extensional (TE) bulk acoustic modes, each device optimized for a single mode....
Infrared imaging of defects in materials has become a standard tool in nondestructive evaluation (NDE). The most recent version of this technology uses ultrasound to excite the defects by friction or other dissipative effects. This version is greatly enhanced by the use of "chaotic" sound.
In the presented work a piezoelectric fluid sensor featuring both electrodes on one face of the piezoelectric disc (LFE electrode arrangement) is efficiently modeled as a layered structure in the spectral domain. The interaction of piezoelectric disc and sample liquid, which is not fully manageable in an analytical way or too comprehensive for FEM, is modeled in a full-wave fashion by the method....
Energy harvesting has the potential to save billions of dollars and create ground breaking technologies for sustainable ocean monitoring systems. Replacement of batteries from the sensors deployed on sea floor is expensive and tedious process. The cost of maintenance for battery operated equipments in the deep waters may be prohibitive. Thus, it is highly desirable to develop a system that harnesses...
A methodology to characterize the complex dielectric permittivity of low-loss materials at millimeter and submillimeter wavelengths, based on whispering gallery mode dielectric resonators, is presented, together with some illustrative results.
Plasmon resonances are able to produce a large field enhancement, which can be exploited for various purposes, such as biosensing or optical mixing. In this paper, the plasmon resonance of two stacked gold nanodisks separated by a tiny 2 nm gap is studied in time-domain simulations, offering the possibility of transient and broadband analysis. Moreover, time-domain simulations are amenable to extensions...
The cylindrical cavity resonator method is presented to evaluate the complex relative permittivity of lossy materials. The loaded sample in the cavity is required to have the rotational symmetry but may have bulky and/or wide sample. To measure the sample at the specified frequency with high Q, movable dielectric supports with low permittivity and low loss are loaded in cavity. Theoretical basis of...
The paper presents a theoretical analysis of the electromagnetic field evolution in a linear chain of coupled circular dielectric resonators when their material is subject to abrupt time change in permittivity. Possibilities of the frequency shift are discussed.
Hollow-core thin silica tubes based on antiresonant guiding mechanism are studied with Terahertz (THz) time domain spectroscopy (TDS) setup. By controlling the parameters of the waveguide, broad transmission windows, up to 580 GHz, is demonstrated at terahertz frequencies.
Recently, flapping robots are noticed by many researchers, and many challenges are being made toward the realization of flight motions like insects, birds and so on. The purpose of this work is to develop flapping robots using a new type of piezoelectric material, that is, piezoelectric fiber composites. By using the composites, actuating as well as energy-harvesting fibers and sensing fibers can...
Piezoelectric energy harvesters are being examined thoroughly as a potential source of electrical power when harnessing surrounding mechanical vibrations. In literature, high frequency energy harvesters are discussed in sufficient details. The development of piezoelectric energy harvester becomes extremely challenging when source vibration frequency is very low. This is due to incompatible stiffness...
Material characterization is an important part of printable electronics design since material properties depend strongly on the manufacturing process. This paper introduces a novel multiline material characterization method that is applicable to the characterization of printable electronics structures as well as integrated microwave devices. The proposed technique eliminates the half-wave resonances,...
The study on finite element analyses of ultrasonic transducer is presented by using the finite element software ANSYS. The transducer is treated as 1/18 3-D finite element analysis modeling to study the ultrasonic transducer acoustic performance. The model of ultrasonic transducer is used in modal analysis and harmonic solutions to understand its mechanical behavior and its natural frequency. Modal...
In this paper the properties of an ensemble of Swiss rolls are investigated. By fitting an analytical solution to the results of the simulation, the macroscopic permeability and permittivity are determined. For the simulations, boundary integral equations are used, discretized by the method of moments (MoM), which leads to a set of linear equations. To reduce the CPU-time needed to solve the set of...
Field experiences have shown that transmission systems using voltage sourced converters can produce high frequency harmonic resonances in the VSC station environment. Modern XLPE cable terminations using non-geometric stress grading can be susceptible to degradation under these harmonics. The paper presents the high frequency voltage effects in XLPE cable terminations, under conditions that are representative...
An edge correction has been developed providing a considerable enhancement of the accuracy in electromagnetic field calculation. This edge correction is based on a modification of the material parameters in the vicinity of the edge. For non equidistant grids the integrals in the given equation here in the paper have to be calculated for each gridpoint corresponding to the edge which requires a slightly...
The design and characterization of a fast flexure-based, parallel-kinematics XYZ scanner for atomic force microscopy is presented in this article. The objective of the project is to design a AFM scanner with the ability to scan an image at high-speed and high resolution. Finite-element analysis was used to optimize the scanner's design in order to achieve high resonance frequencies. Experimental results...
In this paper, a new modified wideband dipole antenna for passive UHF RFID is designed, simulated, fabricated and tested. The modification is done by adding vertical and horizontal stubs to the structure of the ordinary dipole antenna to reduce its length and broaden its bandwidth. IE3D full-wave electromagnetic simulator is used to simulate the modified dipole and compare it with the ordinary dipole...
This paper present calculations showing the interest of to make gyroscopes that use cuts normal to a three fold symmetry axis of several new materials of call 32 or 3m to build sensitive and stable gyroscopes using lateral field excitation and detection. The main factors of the sensitivity are studied and it is shown that lithium tantalate and gallium phosphate present an interesting ensemble of very...
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