scholarly journals Extraction of Bridge Fundamental Frequencies Utilizing a Smartphone MEMS Accelerometer

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3143 ◽  
Author(s):  
Ahmed Elhattab ◽  
Nasim Uddin ◽  
Eugene OBrien
Keyword(s):  
Stochastic Resonance ◽  
Wireless Sensing ◽  
Mems Accelerometer ◽  
Fundamental Frequencies ◽  
Acceleration Data ◽  
Highly Sensitive ◽  
Output Noise ◽  
Frequency Independent ◽  
Low Sensitivity ◽  
Traffic Operation

Smartphone MEMS (Micro Electrical Mechanical System) accelerometers have relatively low sensitivity and high output noise density. Therefore, it cannot be directly used to track feeble vibrations such as structural vibrations. This article proposes an effective increase in the sensitivity of the smartphone accelerometer utilizing the stochastic resonance (SR) phenomenon. SR is an approach where, counter-intuitively, feeble signals are amplified rather than overwhelmed by the addition of noise. This study introduces the 2D-frequency independent underdamped pinning stochastic resonance (2D-FI-UPSR) technique, which is a customized SR filter that enables identifying the frequencies of weak signals. To validate the feasibility of the proposed SR filter, an iPhone device is used to collect bridge acceleration data during normal traffic operation and the proposed 2D-FI-UPSR filter is used to process these data. The first four fundamental bridge frequencies are successfully identified from the iPhone data. In parallel to the iPhone, a highly sensitive wireless sensing network consists of 15 accelerometers (Silicon Designs accelerometers SDI-2012) is installed to validate the accuracy of the extracted frequencies. The measurement fidelity of the iPhone device is shown to be consistent with the wireless sensing network data with approximately 1% error in the first three bridge frequencies and 3% error in the fourth frequency.

scholarly journals Terahertz characterization of two-dimensional low-conductive layers enabled by metal gratings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Prashanth Gopalan ◽  
Yunshan Wang ◽  
Berardi Sensale-Rodriguez
Keyword(s):  
Optical Transmission ◽  
Terahertz Spectroscopy ◽  
Design Guidelines ◽  
Two Dimensional ◽  
Highly Sensitive ◽  
Transmission Measurements ◽  
Metal Gratings ◽  
Low Sensitivity ◽  
Non Destructive

AbstractWhile terahertz spectroscopy can provide valuable information regarding the charge transport properties in semiconductors, its application for the characterization of low-conductive two-dimensional layers, i.e., σs <  < 1 mS, remains elusive. This is primarily due to the low sensitivity of direct transmission measurements to such small sheet conductivity levels. In this work, we discuss harnessing the extraordinary optical transmission through gratings consisting of metallic stripes to characterize such low-conductive two-dimensional layers. We analyze the geometric tradeoffs in these structures and provide physical insights, ultimately leading to general design guidelines for experiments enabling non-contact, non-destructive, highly sensitive characterization of such layers.

scholarly journals Xpert MTB/RIF Ultra is highly sensitive for the diagnosis of tuberculosis lymphadenitis in an HIV-endemic setting

2021 ◽  
Author(s):  
Stephanie Minnies ◽  
Byron W.P. Reeve ◽  
Loren Rockman ◽  
Georgina Nyawo ◽  
Charissa C. Naidoo ◽  
...  
Keyword(s):  
Clinical Investigation ◽  
False Negative ◽  
Needle Aspiration ◽  
World Health ◽  
Number Of Patients ◽  
Highly Sensitive ◽  
Specimen Processing ◽  
Increased Sensitivity ◽  
Health Organization ◽  
Low Sensitivity

Background: Tuberculosis lymphadenitis (TBL) is the most common extrapulmonary TB (EPTB) manifestation. Xpert MTB/RIF Ultra (Ultra) is a World Health Organization-endorsed diagnostic test, but performance data for TBL, including on non-invasive specimens, are limited. Methods: Fine needle aspiration biopsies (FNABs) from outpatients (≥18 years) with presumptive TBL (n=135) underwent: 1) routine Xpert (later Ultra once programmatically available), 2) a MGIT 960 culture (if Xpert- or Ultra-negative, or rifampicin-resistant), and 3) study Ultra. Concentrated paired urine underwent Ultra. Primary analyses used a microbiological reference standard (MRS). Results: In a head-to-head comparison (n=92) of FNAB study Ultra and Xpert, Ultra had increased sensitivity [91% (95% confidence interval 79, 98) vs. 72% (57, 84); p=0.016] and decreased specificity [76% (61, 87) vs. 93% (82, 99); p=0.020], and detected patients not on treatment. HIV nor alternative reference standards affected sensitivity and specificity. In patients with both routine and study Ultras, the latter detected more cases [+20% (0, 42); p=0.034] and, further indicative of potential laboratory-based room-for-improvement (e.g., specimen processing optimisation), false-negative study Ultras were more inhibited than true-positives. Study Ultra false-positives had less mycobacterial DNA than true-positives [trace-positive proportions 59% (13/22) vs. 12% (5/51); p<0.001]. “Trace” exclusion or recategorization removed potential benefits offered over Xpert. Urine Ultra had low sensitivity [18% (7, 35)]. Conclusions: Ultra on FNABs is highly sensitive and detects more TBL than Xpert. Patients with FNAB Ultra-positive “trace” results, most of whom will be culture-negative, may require additional clinical investigation. Urine Ultra could reduce the number of patients needing invasive sampling.

scholarly journals Drive-By Bridge Frequency Identification under Operational Roadway Speeds Employing Frequency Independent Underdamped Pinning Stochastic Resonance (FI-UPSR)

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4207 ◽  
Author(s):  
Ahmed Elhattab ◽  
Nasim Uddin ◽  
Eugene OBrien
Keyword(s):  
Stochastic Resonance ◽  
High Speed ◽  
Dynamic Properties ◽  
Resonance Model ◽  
The Road ◽  
Frequency Independent ◽  
Modes Of Vibration ◽  
Frequency Identification ◽  
A New Technique ◽  
Bridge Vibrations

Recently, drive-by bridge inspection has attracted increasing attention in the bridge monitoring field. A number of studies have given confidence in the feasibility of the approach to detect, quantify, and localize damages. However, the speed of the inspection truck represents a major obstacle to the success of this method. High speeds are essential to induce a significant amount of kinetic energy to stimulate the bridge modes of vibration. On the other hand, low speeds are necessary to collect more data and to attenuate the vibration of the vehicle due to the roughness of the road and, hence, magnify the bridge influence on the vehicle responses. This article introduces Frequency Independent Underdamped Pinning Stochastic Resonance (FI-UPSR) as a new technique, which possesses the ability to extract bridge dynamic properties from the responses of a vehicle that passes over the bridge at high speed. Stochastic Resonance (SR) is a phenomenon where feeble information such as weak signals can be amplified through the assistance of background noise. In this study, bridge vibrations that are present in the vehicle responses when it passes over the bridge are the feeble information while the noise counts for the effect of the road roughness on the vehicle vibration. UPSR is one of the SR models that has been chosen in this study for its suitability to extract the bridge vibration. The main contributions of this article are: (1) introducing a Frequency Independent-Stochastic Resonance model known as the FI-UPSR and (2) implementing this model to extract the bridge vibration from the responses of a fast passing vehicle.

scholarly journals Highly Sensitive Flow Sensor Based on Flexible Dual-Layer Heating Structures

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6657
Author(s):  
Yu-Chao Yan ◽  
Cheng-Yu Jiang ◽  
Run-Bo Chen ◽  
Bing-He Ma ◽  
Jin-Jun Deng ◽  
...  
Keyword(s):  
Heat Conduction ◽  
Convection Heat Transfer ◽  
Single Layer ◽  
Flow Sensor ◽  
Film Sensor ◽  
Highly Sensitive ◽  
Layer Heating ◽  
Low Sensitivity ◽  
Flow Detection ◽  
Hot Film

Hot film sensors detect the flow shear stress based on the forced convection heat transfer to the fluid. Current hot film sensors have been significantly hindered by the relatively low sensitivity due to the massive heat conduction to the substrate. This paper describes the design, fabrication, simulation, and testing of a novel flow sensor with dual-layer hot film structures. More specifically, the heat conduction was insulated from the sensing heater to the substrate by controlling both sensing and guarding heaters working at the same temperature, resulting in a higher sensitivity. The experiment and simulation results showed that the sensitivity of the dual-layer hot film sensor was significantly improved in comparison to the single-layer sensor. Additionally, the dual-layer sensor was designed and fabricated in an integrated, flexible, and miniaturized manner. Its small size makes it an excellent candidate for flow detection.

Comparison of Experimental and Theoretical Intensities for a New X-Ray Tube for Light Element Analysis

1983 ◽  
Vol 27 ◽  
pp. 423-426 ◽  
Author(s):  
John Kikkert ◽  
Graham Hendry
Keyword(s):  
Atomic Number ◽  
Light Element ◽  
Fluorescence Spectrometry ◽  
Light Elements ◽  
Element Analysis ◽  
X Ray ◽  
Highly Sensitive ◽  
Low Sensitivity

While x-ray fluorescence spectrometry is a highly sensitive and highly repoducible method of analysing samples, its one weakness is its relatively low sensitivity for light elements. This is mainly due to two problems: firstly the low fluorescent yield of the low atomic number elements, and secondly to the inherent inefficiency of exciting these elements. While it is not possible to improve the fluorescent yield, considerable improvements in light element sensitivity can be achieved by improvements in x-ray tubes.

A CHARACTERIZATION OF SUPRATHRESHOLD STOCHASTIC RESONANCE IN AN ARRAY OF COMPARATORS BY CORRELATION COEFFICIENT

2002 ◽  
Vol 02 (03) ◽  
pp. L205-L220 ◽  
Author(s):  
MARK D. MCDONNELL ◽  
DEREK ABBOTT ◽  
CHARLES E. M. PEARCE
Keyword(s):  
Correlation Coefficient ◽  
Stochastic Resonance ◽  
Output Signal ◽  
Quantization Noise ◽  
Alternative Measure ◽  
Neuron Models ◽  
Input Noise ◽  
Input Signals ◽  
Output Noise ◽  
Suprathreshold Stochastic Resonance

Suprathreshold Stochastic Resonance (SSR), as described recently by Stocks, is a new form of Stochastic Resonance (SR) which occurs in arrays of nonlinear elements subject to aperiodic input signals and noise. These array elements can be threshold devices or FitzHugh-Nagumo neuron models for example. The distinguishing feature of SSR is that the output measure of interest is not maximized simply for nonzero values of input noise, but is maximized for nonzero values of the input noise to signal intensity ratio, and the effect occurs for signals of arbitrary magnitude and not just subthreshold signals. The original papers described SSR in terms of information theory. Previous work on SR has used correlation based measures to quantify SR for aperiodic input signals. Here, we argue the validity of correlation based measures and derive exact expressions for the cross-correlation coefficient in the same system as the original work, and show that the SSR effect also occurs in this alternative measure. If the output signal is thought of as a digital estimate of the input signal, then the output noise can be considered simply as quantization noise. We therefore derive an expression for the output signal to quantization noise ratio, and show that SSR also occurs in this measure.

scholarly journals Detection of Coxiella burnetii Using Silicon Microring Resonator in Patient Blood Plasma

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 427 ◽  
Author(s):  
Bonhan Koo ◽  
Choong Eun Jin ◽  
Moonsuk Bae ◽  
Yoon Ok Jang ◽  
Ji Yeun Kim ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Blood Plasma ◽  
Coxiella Burnetii ◽  
Q Fever ◽  
Microring Resonator ◽  
Clinical Samples ◽  
Plasma Samples ◽  
Label Free ◽  
Highly Sensitive ◽  
Low Sensitivity

Blood plasma from patients is a powerful resource for diagnosing infectious disease due to it having many genetic materials as well as being relatively easy to obtain. Thus, various biosensors have been investigated for diagnosing diseases in blood plasma. However, there are no optimized and validated sensors for clinical use due to the low sensitivity, complexity, and difficulties of removing the inhibitors from plasma samples. In this study, we described a silicon microring resonator sensor used to detect Coxiella burnetii from the blood plasma of Q-fever patients in a label-free, real-time manner. Q-fever is an infectious disease caused by Coxiella burnetii via direct contact or inhalation aerosols. We validated this biosensor in the blood plasma of 35 clinical samples (including 16 Q fever samples infected with Coxiella burnetii and 19 samples infected with other febrile diseases. The biosensors are capable of rapid (10 min), highly sensitive (87.5%), and specific (89.5%) detection in plasma samples compared to the use of the conventional method.

Rhombic-magnetoelastic/metal–organic framework functionalized resonators for highly sensitive toluene detection

2020 ◽  
Vol 8 (39) ◽  
pp. 13743-13753
Author(s):  
Paula G. Saiz ◽  
Roberto Fernández de Luis ◽  
Luis Bartolome ◽  
Jon Gutiérrez ◽  
María Isabel Arriortua ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Wireless Sensing ◽  
Highly Sensitive ◽  
Metal Organic ◽  
Magnetoelastic Sensors ◽  
Organic Framework

Rhombic magnetoelastic sensors functionalized with MOFs have been applied for the wireless sensing of VOCs showing very promising results.

scholarly journals Unravelling cytosolic delivery of endosomal escape peptides with a quantitative endosomal escape assay (SLEEQ)

2020 ◽  
Author(s):  
Serena L.Y. Teo ◽  
Joshua J. Rennick ◽  
Daniel Yuen ◽  
Hareth Al-Wassiti ◽  
Angus P.R. Johnston ◽  
...  
Keyword(s):  
Endosomal Escape ◽  
Current Understanding ◽  
Specific Cell ◽  
Essential Requirement ◽  
Intracellular Drug Delivery ◽  
Cytosolic Delivery ◽  
Efficient Delivery ◽  
Highly Sensitive ◽  
Therapeutic Peptides ◽  
Low Sensitivity

AbstractEndosomal escape is an essential requirement but a major obstacle to efficient delivery of therapeutic peptides, proteins and nucleic acids. Current understanding of endosomal escape mechanisms remains limited due to significant number of conflicting reports, which are compounded by low sensitivity and indirect assays. To resolve this, we developed a highly sensitive Split Luciferase Endosomal Escape Quantification (SLEEQ) assay to probe mechanisms of cytosolic delivery. We applied SLEEQ to evaluate the endosomal escape of a range of widely studied putative endosomal escape peptides (EEPs). We demonstrated that positively-charged EEPs enhanced cytosolic delivery as a result of increased non-specific cell membrane association, rather than increased endosomal escape efficiency. These findings transform our current understanding of how EEPs increase cytosolic delivery. SLEEQ is a powerful tool that addresses fundamental questions in intracellular drug delivery and will significantly improve the way materials are engineered to increase therapeutic delivery to the cytosol.

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