Research on Novel CMUTs for Detecting Micro-Pressure with Ultra-High Sensitivity and Linearity

Capacitive micromachined ultrasonic transducers (CMUTs) have been indispensable owing to their resonance characteristics in the MHz frequency range. However, the inferior pressure sensitivity and linearity of traditional CMUTs themselves cannot meet the actual demands of micro-pressure measurements. In this paper, two novel CMUTs are proposed for the first time to improve the measuring performance of micro-pressure in the range of 0–10 kPa. The core concept of the enhancement is strengthening membrane deformability by partly adjusting the CMUT framework under the combined action of electrostatic force and uniform pressure. Two modified structures of an inverted frustum cone-like cavity and slotted membrane are presented, respectively, and a finite element model (FEM) of CMUT was constructed and analyzed using COMSOL Multiphysics 5.5. The results demonstrate that the maximum displacement and pressure sensitivity are improved by 16.01% and 30.79% for the frustum cone-like cavity and 104.22% and 1861.31% for the slotted membrane, respectively. Furthermore, the results show that the width uniformity of the grooves does not influence the characteristics of the membrane, which mainly depend on the total width of the grooves, greatly enriching design flexibility. In brief, the proposed structural designs can significantly improve the micro-pressure measurement performance of the CMUT, which will accelerate the rapid breakthrough of technical barriers in the fields of aerospace, industry control, and other sensing domains.

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Magnetoelastic Coupling and Delta-E Effect in Magnetoelectric Torsion Mode Resonators

Sensors ◽

10.3390/s21062022 ◽

2021 ◽

Vol 21 (6) ◽

pp. 2022

Author(s):

Benjamin Spetzler ◽

Elizaveta V. Golubeva ◽

Ron-Marco Friedrich ◽

Sebastian Zabel ◽

Christine Kirchhof ◽

...

Keyword(s):

Low Frequency ◽

High Sensitivity ◽

Element Model ◽

Mode Number ◽

Frequency Change ◽

General Description ◽

Resonance Modes ◽

Field Sensor ◽

Magnetic Sensitivity ◽

Bending Modes

Magnetoelectric resonators have been studied for the detection of small amplitude and low frequency magnetic fields via the delta-E effect, mainly in fundamental bending or bulk resonance modes. Here, we present an experimental and theoretical investigation of magnetoelectric thin-film cantilevers that can be operated in bending modes (BMs) and torsion modes (TMs) as a magnetic field sensor. A magnetoelastic macrospin model is combined with an electromechanical finite element model and a general description of the delta-E effect of all stiffness tensor components Cij is derived. Simulations confirm quantitatively that the delta-E effect of the C66 component has the promising potential of significantly increasing the magnetic sensitivity and the maximum normalized frequency change ∆fr. However, the electrical excitation of TMs remains challenging and is found to significantly diminish the gain in sensitivity. Experiments reveal the dependency of the sensitivity and ∆fr of TMs on the mode number, which differs fundamentally from BMs and is well explained by our model. Because the contribution of C11 to the TMs increases with the mode number, the first-order TM yields the highest magnetic sensitivity. Overall, general insights are gained for the design of high-sensitivity delta-E effect sensors, as well as for frequency tunable devices based on the delta-E effect.

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Imaging the Human Thyroid Using Three-Dimensional Diffuse Optical Tomography: A Preliminary Study

Applied Sciences ◽

10.3390/app11041670 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1670

Author(s):

Tetsuya Mimura ◽

Shinpei Okawa ◽

Hiroshi Kawaguchi ◽

Yukari Tanikawa ◽

Yoko Hoshi

Keyword(s):

Optical Tomography ◽

Tumor Hypoxia ◽

Three Dimensional ◽

Diffuse Optical Tomography ◽

Element Model ◽

Needle Aspiration ◽

Human Thyroid ◽

Tissue Oxygen Saturation ◽

Preliminary Study ◽

First Time

Thyroid cancer is usually diagnosed by ultrasound imaging and fine-needle aspiration biopsy. However, diagnosis of follicular thyroid carcinomas (FTC) is difficult because FTC lacks nuclear atypia and a consensus on histological interpretation. Diffuse optical tomography (DOT) offers the potential to diagnose FTC because it can measure tumor hypoxia, while image reconstruction of the thyroid is still challenging mainly due to the complex anatomical features of the neck. In this study, we attempted to solve this issue by creating a finite element model of the human neck excluding the trachea (a void region). By reconstruction of the absorption coefficients at three wavelengths, 3D tissue oxygen saturation maps of the human thyroid are obtained for the first time by DOT.

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Finite Element Analysis of the ESTELA M1 Airplane Firewall (Representative Specimen)

Volume 3: Design and Manufacturing ◽

10.1115/imece2011-64511 ◽

2011 ◽

Author(s):

V. Ramirez-Elias ◽

E. Ledesma-Orozco ◽

H. Hernandez-Moreno

Keyword(s):

Finite Element ◽

Federal Aviation Administration ◽

Element Model ◽

Maximum Load ◽

Load Factor ◽

Representative Specimen ◽

Maximum Displacement ◽

Element Analysis ◽

Element Simulation ◽

The Relationship

This paper shows the finite element simulation of a representative specimen from the firewall section in the AEROMARMI ESTELA M1 aircraft. This specimen is manufactured in glass and carbon / epoxy laminates. The specimen is subjected to a load which direction and magnitude are determined by a previous dynamic loads study [10], taking into account the maximum load factor allowed by the FAA (Federal Aviation Administration) for utilitarian aircrafts [11]. A representative specimen is manufactured with the same features of the firewall. Meanwhile a fix is built in order to introduce the load directions on the representative specimen. The relationship between load and displacement is plotted for this representative specimen, whence the maximum displacement at the specific load is obtained, afterwards it is compared with the finite element model, which is modified in its laminate thicknesses in order to decrease the deviation error; subsequently this features could be applied to perform the whole firewall analysis in a future model [10].

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Synthesis of single-crystalline GeS nanoribbons for high sensitivity visible-light photodetectors

Journal of Materials Chemistry C ◽

10.1039/c5tc01435b ◽

2015 ◽

Vol 3 (31) ◽

pp. 8074-8079 ◽

Cited By ~ 66

Author(s):

Changyong Lan ◽

Chun Li ◽

Yi Yin ◽

Huayang Guo ◽

Shuai Wang

Keyword(s):

Visible Light ◽

Vapor Deposition ◽

High Performance ◽

Incident Light ◽

Chemical Vapor ◽

High Sensitivity ◽

Single Crystalline ◽

Promising Application ◽

Photo Detection ◽

First Time

Single-crystalline GeS nanoribbons were synthesized by chemical vapor deposition for the first time. The nanoribbon photodetectors respond to the entire visible incident light with a response edge at around 750 nm and a high responsivity, indicating their promising application for high performance broadband visible-light photo-detection.

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Perforation mechanics of UHMWPE soft ballistic sub-laminate and soft ballistic armor pack: A finite element study

Journal of Thermoplastic Composite Materials ◽

10.1177/08927057211042058 ◽

2021 ◽

pp. 089270572110420

Author(s):

Bazle Z (Gama) Haque ◽

John W Gillespie

Keyword(s):

Finite Element ◽

Single Layer ◽

Areal Density ◽

Element Model ◽

Transverse Impact ◽

Free Standing ◽

Uhmwpe Fibers ◽

Ballistic Limit Velocity ◽

Definition Of ◽

First Time

Soft-ballistic sub-laminate (SBSL) made from ultra-high molecular weight polyethylene (UHMWPE) fibers in [0/90] stacking sequence are the building block of a multi-layer soft-ballistic armor pack (SBAP, aka Soft Armor). A systematic study of the perforation dynamics of a single layer SBSL and several multi-layer SBAPs (2, 3, 4, 8, 16, 24, 32 layers) is presented for the first time in the literature. A previously validated finite element model of transverse impact on a single layer is used to study the perforation mechanics of multi-layer SBAPs with friction between individual layers. Following the classical definition of ballistic limit velocity, a minimum perforation velocity has been determined for free-standing single layer SBSL and multi-layer SBAPs. For the multi-layer SBAPs, complete perforations have been identified as progressive perforation of individual layers through the thickness. The minimum perforation velocities of multi-layer SBAPS is linear with the areal density for the eight (8) layer target and thicker. Large deformation behavior and perforation mechanics of the SBAPs is discussed in detail.

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A Frequency-Tunable Comb Resonator Using Spring Tension and Compression Effects

Microelectromechanical Systems ◽

10.1115/imece2004-62148 ◽

2004 ◽

Cited By ~ 1

Author(s):

Ki Bang Lee ◽

Albert P. Pisano ◽

Liwei Lin

Keyword(s):

Resonant Frequency ◽

Bias Voltage ◽

Frequency Tuning ◽

Electrostatic Force ◽

Voltage Change ◽

Tension And Compression ◽

Frequency Tunable ◽

Frequency Changes ◽

Compression Effects ◽

First Time

A 2μm-thick frequency-tunable microresoantor capable of either increasing or decreasing its resonant frequency by a combination of Joule heating and electrostatic force has been successfully demonstrated for the first time. For the heating voltage increase from 0 to 2V under fixed bias voltage of 40V, the resonant frequency changes from 22.2kHz to 16.2kHz, resulting in the 27% reduction in the resonant frequency. For the bias voltage change from 20V to 40V under the heating voltage of 0V, the resonant frequency increase from 19.0kHz to 23.6kHz, resulting in the 24.2% increase in the resonant frequency. As such, this surface-micromachined microactuator could assist complicated frequency tuning for applications of microsensors and microactuators.

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Physical Principles of a Piezo Accelerometer Sensitive to a Nearly Constant Signal

Sensors ◽

10.3390/s18103258 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3258 ◽

Cited By ~ 2

Author(s):

Valery Gupalov ◽

Alexander Kukaev ◽

Sergey Shevchenko ◽

Egor Shalymov ◽

Vladimir Venediktov

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Frequency Band ◽

Linear Acceleration ◽

High Sensitivity ◽

Element Model ◽

Wide Frequency Band ◽

Piezoelectric Accelerometer ◽

The Finite Element Model ◽

Physical Principles

The paper considers the construction of a piezoelectric accelerometer capable of measuring constant linear acceleration. A number of designs are proposed that make it possible to achieve high sensitivity with small dimensions and a wide frequency band (from 10−5 Hz). The finite element model of the proposed design was investigated, and its output characteristic and scale factor (36 mV/g) were obtained.

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Measuring Thiols in Single Cultivar South African Red Wines Using 4,4-Dithiodipyridine (DTDP) Derivatization and Ultraperformance Convergence Chromatography-Tandem Mass Spectrometry

Foods ◽

10.3390/foods7090138 ◽

2018 ◽

Vol 7 (9) ◽

pp. 138 ◽

Cited By ~ 4

Author(s):

Mpho Mafata ◽

Maria Stander ◽

Baptiste Thomachot ◽

Astrid Buica

Keyword(s):

South African ◽

Red Wine ◽

High Sensitivity ◽

White Wine ◽

Wine Aroma ◽

Low Concentrations ◽

Varietal Thiols ◽

Cultivar Differentiation ◽

First Time ◽

Ionization Methods

Wine varietal thiols are important contributors to wine aroma. The chemical nature of thiols makes them difficult to measure due to low concentrations, high sensitivity to oxidation, and low ionization. Methods for the measurement of thiols usually consist of multiple steps of sample preparation followed by instrumental measurement. Studies have collected large datasets of thiols in white wine but not in red wine, due to the lack of availability of suitable methods. In this study, for the first time, convergence chromatography was used to measure thiols in red wine at ultratrace levels with improved sensitivity compared to previous methods. Performance parameters (selectivity, linearity, limits of detection, precision, accuracy) were tested to demonstrate the suitability of the method for the proposed application. Red wine thiols were measured in South African Pinotage, Shiraz, and Cabernet Sauvignon wines (n = 16 each). Cultivar differentiation using the thiol profile was demonstrated.

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Detection of isoprene traces in exhaled breath by using photonic crystals as a biomarker for chronic liver fibrosis disease

10.21203/rs.3.rs-443784/v1 ◽

2021 ◽

Author(s):

Ahmed Mehaney ◽

Hussein A. Elsayed ◽

Ashour M. Ahmed

Keyword(s):

Liver Fibrosis ◽

Photonic Crystals ◽

High Sensitivity ◽

Dielectric Materials ◽

Exhaled Breath ◽

Air Cavity ◽

One Dimensional ◽

Sensor Structure ◽

Volatile Organic ◽

First Time

Abstract Detection of blood-carried volatile organic compounds (VOCs) existing in the exhaled breath of human is an attractive research point for noninvasive diagnosis of diseases. In this research, we introduce a novel application of photonic crystals (PCs) for the detection of isoprene traces in the exhaled breath as a biomarker for liver fibrosis. This idea is introduced for the first time according to the best of our knowledge. The proposed sensor structure is a one-dimensional (1D) PC constructed from a multilayer stack of two dielectric materials covered with an air cavity layer filled with the dry exhaled breath (DEB) and a thin metallic layer of Au is attached on the top surface. Hence, the proposed sensor is configured as, [prism/Au/air cavity/(GaN/SiO2)10]. The transfer matrix method and the Drude model are adopted to calculate the numerical simulations and reflection spectra of the design. The essential key for sensing isoprene levels is the resonant optical Tamm plasmon (TP) states within the photonic bandgap. The obtained numerical results are promising such as high sensitivity (S) of 0.321 nm/ppm or 278720 nm/RIU. This technique can be reducing the risk of infection during the taking of blood samples by syringe. Also, it can prevent the pain of patients. Finally, this work opens the door for the detection of many diseases by analyzing the breaths of patients based on photonic crystals.

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The optimum cut-off value to differentiate Echinococcus granulosus sensu stricto from other species of E. granulosus sensu lato using larval rostellar hook morphometry

Journal of Helminthology ◽

10.1017/s0022149x13000473 ◽

2013 ◽

Vol 89 (1) ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

S.V. Soriano ◽

N.B. Pierangeli ◽

L.A. Pianciola ◽

M. Mazzeo ◽

L.E. Lazzarini ◽

...

Keyword(s):

Molecular Epidemiology ◽

Echinococcus Granulosus ◽

Cystic Echinococcosis ◽

Control Strategies ◽

High Sensitivity ◽

Field Studies ◽

Sensu Stricto ◽

Roc Curve Analysis ◽

First Time

AbstractCystic echinococcosis caused by Echinococcus granulosus sensu lato is one of the most important helminth zoonoses in the world; it affects both humans and livestock. The disease is endemic in Argentina and highly endemic in the province of Neuquén. Considerable genetic and phenotypic variation has been demonstrated in E. granulosus, and ten different genotypes (G1–G10) have been identified using molecular tools. Echinococcus granulosus sensu lato may be considered a species complex, comprised of E. granulosus sensu stricto (G1–G3), E. equinus (G4), E. ortleppi (G5) and E. canadensis (G6–G10). In endemic areas, the characterization of cystic echinococcosis molecular epidemiology is important in order to apply adequate control strategies. A cut-off value for larval large hook total length to distinguish E. granulosus sensu stricto isolates from those produced by other species of the complex was defined for the first time. Overall, 1780 larval hooks of 36 isolates obtained from sheep (n= 11, G1), goats (n= 10, G6), cattle (n= 5, G6) and pigs (n= 10, G7) were analysed. Validation against molecular genotyping as gold standard was carried out using the receiver operating characteristic (ROC) curve analysis. The optimum cut-off value was defined as 26.5 μm. The proposed method showed high sensitivity (97.8%) and specificity (91.1%). Since in most endemic regions the molecular epidemiology of echinococcosis includes the coexistence of the widely distributed E. granulosus sensu stricto G1 strain and other species of the complex, this technique could be useful as a quick and economical tool for epidemiological and surveillance field studies, when fertile cysts are present.

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