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Full-Text Articles in Engineering
An Analytical Model Of A Thermally Excited Microcantilever Vibrating Laterally In A Viscous Fluid, Stephen M. Heinrich, Rabin Maharjan, Isabelle Dufour, Fabien Josse, Luke A. Beardslee, Oliver Brand
An Analytical Model Of A Thermally Excited Microcantilever Vibrating Laterally In A Viscous Fluid, Stephen M. Heinrich, Rabin Maharjan, Isabelle Dufour, Fabien Josse, Luke A. Beardslee, Oliver Brand
Civil and Environmental Engineering Faculty Research and Publications
To achieve higher quality factors (Q) for microcantilevers used in liquid-phase sensing applications, recent studies have explored the use of the lateral (in-plane) flexural mode. In particular, we have recently shown that this mode may be excited electrothermally using integrated heating resistors near the micro cantilever support, and that the resulting increase in Q helps to make low-ppb limits of detection a possibility in liquids. However, because the use of electrothermally excited, liquid-phase, microcantilever-based sensors in lateral flexure is relatively new, theoretical models are lacking. Therefore, we present here a new analytical model for predicting the vibratory response of these …
Geometrical Optimization Of Resonant Cantilevers Vibrating In In-Plane Bending Modes, Luke A. Beardslee, Assim M. Addous, Kemal S. Demirci, Oliver Brand, Stephen M. Heinrich, Fabien Josse
Geometrical Optimization Of Resonant Cantilevers Vibrating In In-Plane Bending Modes, Luke A. Beardslee, Assim M. Addous, Kemal S. Demirci, Oliver Brand, Stephen M. Heinrich, Fabien Josse
Civil and Environmental Engineering Faculty Research and Publications
The influence of the beam geometry on the quality factor and resonance frequency of resonant silicon cantilever beams vibrating in their fundamental in-plane flexural mode has been investigated in air and water. Compared to cantilevers vibrating in their out-of-plane flexural mode, utilizing the in plane mode results in reduced damping and reduced mass loading by the surrounding fluid. Quality factors as high as 4,300 in air and 67 in water have been measured for cantilevers with a 12 μm thick silicon layer. This is in comparison to Q factors up to 1,500 in air and up to 20 in water …
Liquid-Phase Chemical Sensing Using Lateral Mode Resonant Cantilevers, Luke A. Beardslee, Kemal S. Demirci, Y. Luzinova, B. Mizaikoff, Stephen M. Heinrich, Fabien Josse, Oliver Brand
Liquid-Phase Chemical Sensing Using Lateral Mode Resonant Cantilevers, Luke A. Beardslee, Kemal S. Demirci, Y. Luzinova, B. Mizaikoff, Stephen M. Heinrich, Fabien Josse, Oliver Brand
Civil and Environmental Engineering Faculty Research and Publications
Liquid-phase operation of resonant cantilevers vibrating in an out-of-plane flexural mode has to date been limited by the considerable fluid damping and the resulting low quality factors (Q factors). To reduce fluid damping in liquids and to improve the detection limit for liquid-phase sensing applications, resonant cantilever transducers vibrating in their in-plane rather than their out-of-plane flexural resonant mode have been fabricated and shown to have Q factors up to 67 in water (up to 4300 in air). In the present work, resonant cantilevers, thermally excited in an in-plane flexural mode, are investigated and applied as sensors for volatile …
Thermal Excitation And Piezoresistive Detection Of Cantilever In-Plane Resonance Modes For Sensing Applications, Luke A. Beardslee, Assim M. Addous, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Oliver Brand
Thermal Excitation And Piezoresistive Detection Of Cantilever In-Plane Resonance Modes For Sensing Applications, Luke A. Beardslee, Assim M. Addous, Stephen M. Heinrich, Fabien Josse, Isabelle Dufour, Oliver Brand
Civil and Environmental Engineering Faculty Research and Publications
Thermally excited and piezoresistively detected bulk-micromachined cantilevers vibrating in their in-plane flexural resonance mode are presented. By shearing the surrounding fluid rather than exerting normal stress on it, the in-plane mode cantilevers exhibit reduced added fluid mass effects and improved quality factors in a fluid environment. In this letter, different cantilever geometries with in-plane resonance frequencies from 50 kHz to 2.2 MHz have been tested, with quality factors as high as 4200 in air and 67 in water.
Resonant Microcantilevers Vibrating Laterally In Viscous Liquid Media, Russell Cox, Fabien Josse, Stephen M. Heinrich, Isabelle Dufour, Oliver Brand
Resonant Microcantilevers Vibrating Laterally In Viscous Liquid Media, Russell Cox, Fabien Josse, Stephen M. Heinrich, Isabelle Dufour, Oliver Brand
Civil and Environmental Engineering Faculty Research and Publications
The characteristics of microcantilevers vibrating in the in-plane flexural mode (also known as lateral vibration) in viscous liquid media are investigated. A numerical model was utilized to determine a correction to Stokes' solution for an infinite plate to obtain an analytical expression for the hydrodynamic forces acting on a laterally vibrating microcantilever as a function of both Reynolds number and aspect ratio (thickness over width). The results allowed for the resonant frequency and quality factor to be investigated as a function of both beam geometry and medium properties. Trends in these characteristics can be used to optimize device geometry and …
Analyzing Motorists’ Responses To Temporary Signage In Highway Work Zones, Yong Bai, Kris Finger, Yue Li
Analyzing Motorists’ Responses To Temporary Signage In Highway Work Zones, Yong Bai, Kris Finger, Yue Li
Civil and Environmental Engineering Faculty Research and Publications
For decades, the importance of highway work zone safety has increased considerably with the continual increase in the number of highway work zones present on highways for repairs and expansion. Rural work zones on two-lane highways are particularly hazardous and cause a significant safety concern due to the disruption of regular traffic flow. In this study, researchers determined motorists’ responses to warning signs in rural, two-lane highway work zones. The researchers divided vehicles into three classes (passenger car, truck, and semitrailer) and compared the mean change in speed of these classes based on three different sign setups: portable changeable message …
Unconventional Uses Of Cantilevers For Chemical Sensing In Gas And Liquid Environments, Isabelle Dufour, Fabien Josse, Stephen M. Heinrich, C. Lucat, C. Ayela, F. Ménil, Oliver Brand
Unconventional Uses Of Cantilevers For Chemical Sensing In Gas And Liquid Environments, Isabelle Dufour, Fabien Josse, Stephen M. Heinrich, C. Lucat, C. Ayela, F. Ménil, Oliver Brand
Civil and Environmental Engineering Faculty Research and Publications
Microcantilevers used as (bio)chemical sensors are usually coated with a chemically sensitive layer. The coated devices operate either in a static bending regime or in a dynamic flexural mode. While the coated devices operate generally well in both the static and dynamic mode, they do suffer from certain shortcomings depending on the medium of operation and the application, including lack of selectivity and of reversibility of the sensitive coating and a reduced quality factor due to the surrounding medium. In particular, the performance of microcantilevers excited in their standard out-of-plane dynamic mode drastically decreases in viscous liquid media. Moreover, the …
Tapping Environmental History To Recreate America’S Colonial Hydrology, Christopher L. Pastore, Mark B. Green, Daniel J. Bain, Andrea Muñoz-Hernandez, Charles J. Vörösmarty, Jennifer Arrigo, Sara Brandt, Jonathan M. Duncan, Francesca Greco, Hyojin Kim, Sanjiv Kumar, Michael Lally, Anthony J. Parolari, Brian Pellerin, Nira Salant, Adam Schlosser, Kate Zalzal
Tapping Environmental History To Recreate America’S Colonial Hydrology, Christopher L. Pastore, Mark B. Green, Daniel J. Bain, Andrea Muñoz-Hernandez, Charles J. Vörösmarty, Jennifer Arrigo, Sara Brandt, Jonathan M. Duncan, Francesca Greco, Hyojin Kim, Sanjiv Kumar, Michael Lally, Anthony J. Parolari, Brian Pellerin, Nira Salant, Adam Schlosser, Kate Zalzal
Civil and Environmental Engineering Faculty Research and Publications
To properly remediate, improve, or predict how hydrological systems behave, it is vital to establish their histories. However, modern-style records, assembled from instrumental data and remote sensing platforms, hardly exist back more than a few decades. As centuries of data is preferable given multidecadal fluxes of both meteorology/climatology and demographics, building such a history requires resources traditionally considered only useful in the social sciences and humanities. In this Feature, Pastore et al. discuss how they have undertaken the synthesis of historical records and modern techniques to understand the hydrology of the Northeastern U.S. from Colonial times to modern day. Such …