Using the Nonlinear Duffing Effect of Piezoelectric Micro-Oscillators for Wide-Range Pressure Sensing

This paper investigates the resonant behaviour of silicon-based micro-oscillators with a length of 3600 µm, a width of 1800 µm and a thickness of 10 µm over a wide range of ambient gas (N2) pressures, extending over six orders of magnitude from 10−3 mbar to 900 mbar. The oscillators are actuated piezoelectrically by a thin-film aluminium-nitride (AlN) layer, with the cantilever coverage area being varied from 33% up to 100%. The central focus is on nonlinear Duffing effects, occurring at higher oscillation amplitudes. A theoretical background is provided. All relevant parameters describing a Duffing oscillator, such as stiffness parameters for each coverage size as well as for different bending modes and more complex modes, are extracted from the experimental data. The so-called 2nd roof-tile-shaped mode showed the highest stiffness value of −97.3∙107 m−2s−2. Thus, it was chosen as being optimal for extended range pressure measurements. Interestingly, both a spring softening effect and a spring hardening effect were observed in this mode, depending on the percentage of the AlN coverage area. The Duffing-effect-induced frequency shift was found to be optimal for obtaining the highest pressure sensitivity, while the size of the hysteresis loop is also a very useful parameter because of the possibility of eliminating the temperature influences and long-term drift effects of the resonance frequency. An reasonable application-specific compromise between the sensitivity and the measurement range can be selected by adjusting the excitation voltage, offering much flexibility. This novel approach turns out to be very promising for compact, cost-effective, wide-range pressure measurements in the vacuum range.

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A Resonant Pressure Microsensor with a Wide Pressure Measurement Range

Micromachines ◽

10.3390/mi12040382 ◽

2021 ◽

Vol 12 (4) ◽

pp. 382

Author(s):

Chao Xiang ◽

Yulan Lu ◽

Chao Cheng ◽

Junbo Wang ◽

Deyong Chen ◽

...

Keyword(s):

Chemical Mechanical Planarization ◽

Measurement Range ◽

Silicon On Insulator ◽

Anodic Bonding ◽

Pressure Measurements ◽

Quality Factors ◽

Deep Reactive Ion Etching ◽

Wide Range ◽

Form Pressure ◽

Silicon Islands

This paper presents a resonant pressure microsensor with a wide range of pressure measurements. The developed microsensor is mainly composed of a silicon-on-insulator (SOI) wafer to form pressure-sensing elements, and a silicon-on-glass (SOG) cap to form vacuum encapsulation. To realize a wide range of pressure measurements, silicon islands were deployed on the device layer of the SOI wafer to enhance equivalent stiffness and structural stability of the pressure-sensitive diaphragm. Moreover, a cylindrical vacuum cavity was deployed on the SOG cap with the purpose to decrease the stresses generated during the silicon-to-glass contact during pressure measurements. The fabrication processes mainly contained photolithography, deep reactive ion etching (DRIE), chemical mechanical planarization (CMP) and anodic bonding. According to the characterization experiments, the quality factors of the resonators were higher than 15,000 with pressure sensitivities of 0.51 Hz/kPa (resonator I), −1.75 Hz/kPa (resonator II) and temperature coefficients of frequency of 1.92 Hz/°C (resonator I), 1.98 Hz/°C (resonator II). Following temperature compensation, the fitting error of the microsensor was within the range of 0.006% FS and the measurement accuracy was as high as 0.017% FS in the pressure range of 200 ~ 7000 kPa and the temperature range of −40 °C to 80 °C.

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Silica-encapsulated DNA tracers for measuring aerosol distribution dynamics in real-world settings

10.1101/2021.05.19.21257392 ◽

2021 ◽

Author(s):

Anne M Luescher ◽

Julian Koch ◽

Wendelin J Stark ◽

Robert N Grass

Keyword(s):

Real World ◽

Complex Dynamics ◽

Quantitative Polymerase Chain Reaction ◽

Cost Effective ◽

Confined Space ◽

Aerosol Dynamics ◽

Novel Approach ◽

Aerosol Distribution ◽

Wide Range ◽

Series Of Experiments

Aerosolized particles play a significant role in human health and environmental risk management. The global importance of aerosol-related hazards, such as the circulation of pathogens and high levels of air pollutants, have led to a surging demand for suitable surrogate tracers to investigate the complex dynamics of airborne particles in real-world scenarios. In this study, we propose a novel approach using silica particles with encapsulated DNA (SPED) as a tracing agent for measuring aerosol distribution indoors. In a series of experiments with a portable setup, SPED were successfully aerosolized, re-captured and quantified using quantitative polymerase chain reaction (qPCR). Position-dependency and ventilation effects within a confined space could be shown in a quantitative fashion achieving detection limits below 0.1 ng particles per m3 of sampled air. In conclusion, SPED show promise for a flexible, cost-effective and low-impact characterization of aerosol dynamics in a wide range of settings.

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3D-Printable Carbon Nanotubes-Based Composite for Flexible Piezoresistive Sensors

Materials ◽

10.3390/ma13235482 ◽

2020 ◽

Vol 13 (23) ◽

pp. 5482

Author(s):

Chaima Fekiri ◽

Ho Chan Kim ◽

In Hwan Lee

Keyword(s):

Carbon Nanotubes ◽

Flexible Electronics ◽

Applied Pressure ◽

Structural Complexity ◽

High Sensitivity ◽

Cost Effective ◽

Measurement Range ◽

Resistance Change ◽

Piezoresistive Pressure Sensor ◽

Wide Range

The intersection between nanoscience and additive manufacturing technology has resulted in a new field of printable and flexible electronics. This interesting area of research tackles the challenges in the development of novel materials and fabrication techniques towards a wider range and improved design of flexible electronic devices. This work presents the fabrication of a cost-effective and facile flexible piezoresistive pressure sensor using a 3D-printable carbon nanotube-based nanocomposite. The carbon nanotubes used for the development of the material are multi-walled carbon nanotubes (MWCNT) dispersed in polydimethylsiloxane (PDMS) prepolymer. The sensor was fabricated using the direct ink writing (DIW) technique (also referred to as robocasting). The MWCNT-PDMS composite was directly printed onto the polydimethylsiloxane substrate. The sensor response was then examined based on the resistance change to the applied load. The sensor exhibited high sensitivity (6.3 Ω/kPa) over a wide range of applied pressure (up to 1132 kPa); the highest observed measurement range for MWCNT-PDMS composite in previous work was 40 kPa. The formulated MWCNT-PDMS composite was also printed into high-resolution 3-dimensional shapes which maintained their form even after heat treatment process. The possibility to use 3D printing in the fabrication of flexible sensors allows design freedom and flexibility, and structural complexity with wide applications in wearable or implantable electronics for sport, automotive and biomedical fields.

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Daycase trauma list: a safe and cost-effective service delivery

Annals of The Royal College of Surgeons of England ◽

10.1308/rcsann.2019.0058 ◽

2019 ◽

Vol 101 (7) ◽

pp. 519-521

Author(s):

MS Athar ◽

MA Fazal ◽

N Ashwood ◽

G Arealis ◽

D Buchanan ◽

...

Keyword(s):

Patient Satisfaction ◽

Lower Limb ◽

Trauma Surgery ◽

Cost Effective ◽

High Patient Satisfaction ◽

Trauma Service ◽

Novel Approach ◽

Wide Range ◽

The Mean ◽

Effective Service

Introduction Daycase trauma surgery is an evolving and a novel approach. The aim of our study was to report our experience of daycase trauma surgery with a focus on safety, patient experience, complications and limitations. Material and methods Patients scheduled and operated on a daycase trauma list from January 2013 to December 2016 were included in the study. Age, sex, case mix, readmissions within 48 hours, complications, patient satisfaction, reasons for overnight stay and cost effectiveness were evaluated. Results A total of 229 procedures were carried out. The mean age of the patients was 44.3 years (range 16–85 years) . There were 128 men and 101 women, 178 upper-limb and 51 lower-limb cases. Only 2.6% of the patients had stayed overnight for pain control, physiotherapy and neurological observations; 94.5% of the patients were satisfied. The mean visual analogue scale score for satisfaction was 8.7. There were no admissions within 48 hours of discharge and one complication with failure of ankle fixation. The estimated cost saving was £65,562. Conclusion We conclude that a daycase trauma service is safe, cost effective, and yields high patient satisfaction. It reduces the burden on hospital beds and a wide range of upper- and lower-limb cases can be performed as daycase trauma surgery with adequate planning and teamwork.

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In-house reverse transcriptase polymerase chain reaction for detection of SARS-CoV-2 with increased sensitivity

Scientific Reports ◽

10.1038/s41598-021-97502-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Manash Jyoti Kalita ◽

Kalpajit Dutta ◽

Gautam Hazarika ◽

Ridip Dutta ◽

Simanta Kalita ◽

...

Keyword(s):

Multiplex Pcr ◽

Real Time ◽

Real Time Pcr ◽

Cost Effective ◽

Sybr Green ◽

Green Approach ◽

Novel Approach ◽

Effective Manner ◽

Wide Range ◽

Thermal Cycler

AbstractAs the COVID-19 infection continues to ravage the world, the advent of an efficient as well as the economization of the existing RT-PCR based detection assay essentially can become a blessing in these testing times and significantly help in the management of the pandemic. This study demonstrated an innovative and rapid corroboration of COVID-19 test based on innovative multiplex PCR. An assessment of optimal PCR conditions to simultaneously amplify the SARS-CoV-2 genes E, S and RdRp has been made by fast-conventional and HRM coupled multiplex real-time PCR using the same sets of primers. All variables of practical value were studied by amplifying known target-sequences from ten-fold dilutions of archived positive samples of COVID-19 disease. The multiplexing with newly designed E, S and RdRp primers have shown an efficient amplification of the target region of SARS-CoV-2. A distinct amplification was observed in 37 min using thermal cycler while it took 96 min in HRM coupled real time detection using SYBR green over a wide range of template concentrations. Our findings revealed decent concordance with other commercially available detection kits. This fast HRM coupled multiplex real-time PCR with SYBR green approach offers rapid and sensitive detection of SARS-CoV-2 in a cost-effective manner apart from the added advantage of primer compatibility for use in conventional multiplex PCR. The highly reproducible novel approach can propel extended applicability for developing sustainable commercial product besides providing relief to a resource limited setting.

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2D Color-Intensity Representation of Ultrasonic Thickness Gauge Measurements

Materials Evaluation ◽

10.32548/2020.me-04177 ◽

2020 ◽

pp. 1192-1198

Author(s):

M.S. Mohammad ◽

Tibebe Tesfaye ◽

Kim Ki-Seong

Keyword(s):

Cost Effective ◽

The Other ◽

Thickness Gauge ◽

Color Intensity ◽

Digital Readout ◽

Flat Surfaces ◽

Video Cameras ◽

Wide Range ◽

Cost Effective Alternative ◽

Ultrasonic Thickness

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.

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Worldview-2 and Landsat 8 Satellite Data for Seaweed Mapping along Karachi Coast

Pakistan Journal of Engineering Technology & Science ◽

10.22555/pjets.v5i2.920 ◽

2016 ◽

Vol 5 (2) ◽

Cited By ~ 1

Author(s):

Muhammad Danish Siddiqui ◽

Arjumand Z Zaidi

Keyword(s):

Satellite Data ◽

Spatial Scales ◽

Economic Value ◽

Vegetation Indices ◽

Cost Effective ◽

Geographical Information ◽

Landsat 8 ◽

Coverage Area ◽

Breeding Sites ◽

Marine Plant

Seaweed is a marine plant or algae which has economic value in many parts of the world. The purpose of this study is to evaluate different satellite sensors such as high-resolution WorldView-2 (WV2) satellite data and Landsat 8 30-meter resolution satellite data for mapping seaweed resources along the coastal waters of Karachi. The continuous monitoring and mapping of this precious marine plant and their breeding sites may not be very efficient and cost effective using traditional survey techniques. Remote Sensing (RS) and Geographical Information System (GIS) can provide economical and more efficient solutions for mapping and monitoring coastal resources quantitatively as well as qualitatively at both temporal and spatial scales. Normalized Difference Vegetation Indices (NDVI) along with the image enhancement techniques were used to delineate seaweed patches in the study area. The coverage area of seaweed estimated with WV-2 and Landsat 8 are presented as GIS maps. A more precise area estimation wasachieved with WV-2 data that shows 15.5Ha (0.155 Km2)of seaweed cover along Karachi coast that is more representative of the field observed data. A much larger area wasestimated with Landsat 8 image (71.28Ha or 0.7128 Km2) that was mainly due to the mixing of seaweed pixels with water pixels. The WV-2 data, due to its better spatial resolution than Landsat 8, have proven to be more useful than Landsat 8 in mapping seaweed patches

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The Future of Plasma-Based Surface Engineering Techniques in Tribology (Keynote)

World Tribology Congress III, Volume 2 ◽

10.1115/wtc2005-64180 ◽

2005 ◽

Cited By ~ 1

Author(s):

Allan Matthews ◽

Adrian Leyland

Keyword(s):

Surface Engineering ◽

Performance Enhancement ◽

Bulk Material ◽

Cost Savings ◽

Cost Effective ◽

Ceramic Coatings ◽

Performance Improvements ◽

Treatment Techniques ◽

Wide Range ◽

Macro Scale

Over the past twenty years or so, there have been major steps forward both in the understanding of tribological mechanisms and in the development of new coating and treatment techniques to better “engineer” surfaces to achieve reductions in wear and friction. Particularly in the coatings tribology field, improved techniques and theories which enable us to study and understand the mechanisms occurring at the “nano”, “micro” and “macro” scale have allowed considerable progress to be made in (for example) understanding contact mechanisms and the influence of “third bodies” [1–5]. Over the same period, we have seen the emergence of the discipline which we now call “Surface Engineering”, by which, ideally, a bulk material (the ‘substrate’) and a coating are combined in a way that provides a cost-effective performance enhancement of which neither would be capable without the presence of the other. It is probably fair to say that the emergence and recognition of Surface Engineering as a field in its own right has been driven largely by the availability of “plasma”-based coating and treatment processes, which can provide surface properties which were previously unachievable. In particular, plasma-assisted (PA) physical vapour deposition (PVD) techniques, allowing wear-resistant ceramic thin films such as titanium nitride (TiN) to be deposited on a wide range of industrial tooling, gave a step-change in industrial productivity and manufactured product quality, and caught the attention of engineers due to the remarkable cost savings and performance improvements obtained. Subsequently, so-called 2nd- and 3rd-generation ceramic coatings (with multilayered or nanocomposite structures) have recently been developed [6–9], to further extend tool performance — the objective typically being to increase coating hardness further, or extend hardness capabilities to higher temperatures.

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Gamma models for estimating the odds ratio for a skewed biomarker measured in pools and subject to errors

Biostatistics ◽

10.1093/biostatistics/kxz028 ◽

2019 ◽

Author(s):

Dane R Van Domelen ◽

Emily M Mitchell ◽

Neil J Perkins ◽

Enrique F Schisterman ◽

Amita K Manatunga ◽

...

Keyword(s):

Odds Ratio ◽

Adjusted Odds Ratio ◽

Lower Cost ◽

Cost Effective ◽

Ratio Estimation ◽

Statistical Efficiency ◽

Function Model ◽

Processing Error ◽

Wide Range ◽

Pooled Samples

SUMMARYMeasuring a biomarker in pooled samples from multiple cases or controls can lead to cost-effective estimation of a covariate-adjusted odds ratio, particularly for expensive assays. But pooled measurements may be affected by assay-related measurement error (ME) and/or pooling-related processing error (PE), which can induce bias if ignored. Building on recently developed methods for a normal biomarker subject to additive errors, we present two related estimators for a right-skewed biomarker subject to multiplicative errors: one based on logistic regression and the other based on a Gamma discriminant function model. Applied to a reproductive health dataset with a right-skewed cytokine measured in pools of size 1 and 2, both methods suggest no association with spontaneous abortion. The fitted models indicate little ME but fairly severe PE, the latter of which is much too large to ignore. Simulations mimicking these data with a non-unity odds ratio confirm validity of the estimators and illustrate how PE can detract from pooling-related gains in statistical efficiency. These methods address a key issue associated with the homogeneous pools study design and should facilitate valid odds ratio estimation at a lower cost in a wide range of scenarios.

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Responsive and Personalized Web Layouts with Integer Programming

Proceedings of the ACM on Human-Computer Interaction ◽

10.1145/3461735 ◽

2021 ◽

Vol 5 (EICS) ◽

pp. 1-23

Author(s):

Markku Laine ◽

Yu Zhang ◽

Simo Santala ◽

Jussi P. P. Jokinen ◽

Antti Oulasvirta

Keyword(s):

Integer Programming ◽

Web Design ◽

Web Pages ◽

Web Page Design ◽

Automated Generation ◽

Novel Approach ◽

Wide Range ◽

Responsive Design ◽

Responsive Web Design ◽

Page Design

Over the past decade, responsive web design (RWD) has become the de facto standard for adapting web pages to a wide range of devices used for browsing. While RWD has improved the usability of web pages, it is not without drawbacks and limitations: designers and developers must manually design the web layouts for multiple screen sizes and implement associated adaptation rules, and its "one responsive design fits all" approach lacks support for personalization. This paper presents a novel approach for automated generation of responsive and personalized web layouts. Given an existing web page design and preferences related to design objectives, our integer programming -based optimizer generates a consistent set of web designs. Where relevant data is available, these can be further automatically personalized for the user and browsing device. The paper includes presentation of techniques for runtime adaptation of the designs generated into a fully responsive grid layout for web browsing. Results from our ratings-based online studies with end users (N = 86) and designers (N = 64) show that the proposed approach can automatically create high-quality responsive web layouts for a variety of real-world websites.

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