Download or read book Theoretical Analysis of Laterally Vibrating Microcantilever Sensors in a Viscous Liquid Medium written by Russell Cox and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamically driven microcantilevers are normally excited into resonance in the out-of-plane flexural mode. The beam's resonant frequency and quality factor are used to characterize the devices. The devices are well suited for operation in air, but are limited in viscous liquid media due to the increased viscous damping. In order to improve these characteristics, other vibration modes such as the in-plane (or lateral) flexural mode are investigated. In this work, microcantilevers vibrating in the in-plane flexural mode (or lateral direction) in a viscous liquid medium are investigated. The hydrodynamic forces on the microcantilever as a function of both Reynolds number and aspect ratio (thickness over width) are first calculated using a combination of numerical methods and Stokes' solution. The results allowed for the resonant frequency, quality factor, and mass sensitivity to be investigated as a function of both beam geometry and medium properties. The predicted resonant frequency and quality factor for several different laterally vibrating beams in water are also found to match the trends given by experimentally determined values found in the literature. The results show a significant improvement over those of similar devices vibrating in the out-of-plane flexural mode. The resonant frequency increases by a factor proportional to the inverse of the beam's aspect ratio. Moreover, the resonant frequency of a laterally vibrating beam shows a smaller decrease when immersed in water (5-10% compared to 5̃0% for transversely vibrating beams) and, as the viscosity increases, the resonant frequency decreases slower compared to beams excited transversely. The quality factor is found to increase by a factor of 2-4 or higher depending on the medium of operation and the beam geometry. Due to the increased resonant frequency and the decreased effective mass of the beam (compared to beams excited transversely), the estimated mass sensitivity of a laterally excited microcantilever is found to be much larger (up to two orders of magnitude). The improvement in these characteristics is expected to yield much lower limits of detection in liquid-phase bio-chemical sensing applications.

Download or read book Theoretical Analysis of Laterally Vibrating Hammerhead Microcantilever Sensors in a Viscous Liquid written by Jinjin Zhang and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamically driven prismatic microcantilevers excited in the in-plane flexural mode have been investigated and used in liquid-phase sensing applications. However, the performance is restricted due to their limited surface sensing area and higher stiffness in shorter and wider prismatic microcantilevers. To increase the surface sensing area, and further improve sensing characteristics, it has been proposed to investigate symmetric hammerhead microcantilevers vibrating laterally in viscous liquid media. In this work, a theoretical model is proposed and the characteristics of the microcantilevers with symmetric shaped hammerheads (isosceles trapezoid, semi-circle, uniform rectangle and composite rectangle) are investigated. In the analysis, the stem of the structure is modeled as an Euler-Bernoulli beam while the head is modeled as a rigid body. Since the arbitrary, symmetric head has a varying width, 2b2(x), in the length direction, a new semi-analytical expression for the hydrodynamic function in terms of the Reynolds number, Re(x), and aspect ratio, h/[2b2(x)] is obtained and the resonance frequency, quality factor and mass sensitivity are investigated as a function of both the hammerhead microcantilever geometry and liquid media properties. For the investigated geometries, the results show that, for a hammerhead microcantilever with a fixed head area, as the mass center of the head moves towards the support end of the stem, the resulting resonance frequency and mass sensitivity will first increase and then decrease, because the total kinetic energy will first decrease and then increase. The quality factor will keep increasing, due to a more rapid decrease in the energy dissipation. It is also found that, hammerhead microcantilevers with wider heads tend to have higher quality factors. For instance, the highest quality factors are found for the hammerhead microcantilevers with the isosceles trapezoid-shaped, uniform rectangular and composite rectangular head as 140, 72 and 129, respectively, due to the possible shift of the mass center of the head towards the support end of the stem. Such trends can be used to optimize sensor device geometry and frequency stability. By further increasing the surface sensing area (additional mass), the resonance frequency and the mass sensitivity will significantly decrease. Such trade-offs must be considered when designing the geometry of the hammerhead microcantilever devices. For appropriately designed hammerhead microcantilevers, the improvement in the sensing area and quality factor are expected to yield much lower limits of detection in (bio) chemical sensing applications.

Download or read book Theoretical Analysis of Torsionally Vibrating Microcantilevers for Chemical Sensor Applications in Viscous Liquids written by Tao Cai and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamically driven microcantilevers excited in the transverse (or out-of-plane) direction are widely used as highly sensitive chemical sensing platforms in various applications. While these devices work very well in air, their performance in liquids is not efficient because of the combination of increased viscous damping and effective fluid mass. In order to improve the characteristics of microcantilevers in liquid environments, some other vibration modes such as the torsional mode and lateral (or in-plane) flexural mode have been proposed. In this work, the characteristics of torsionally vibrating rectangular microcantilevers with length L, width b and thickness h in viscous liquids are investigated taking into account the thickness effects. Finite element models are used to obtain the hydrodynamic loading (torque per unit length) and thus calculate values of the hydrodynamic function. An analytical expression of the hydrodynamic function in terms of the Reynolds number and aspect ratio, h/b, is then obtained by fitting the numerical results. This allows for the characteristics to be investigated as a function of both beam geometry and fluid properties, considering thickness effects on the torsional constant, the hydrodynamic function and the polar moment of area. For high aspect ratios, (h/b>0.16) microcantilevers vibrating in the 1st torsional mode, ignoring thickness effects could result in a minimum error of 9%, 5%, 20%, 7% for the resonance frequency, quality factor, mass sensitivity, and normalized mass limit of detection, respectively. Clearly, for many sensing applications based on analyzing the resonance frequency and mass sensitivity, thickness effects should be taken into account. The resonance frequency is found to be dependent on h/(bL) and the quality factor is found to be dependent on h/L1/2 for microcantilevers vibrating in the 1st torsional mode in viscous liquids. In comparison, for microcantilevers vibrating in the 1st lateral mode, the resonance frequency is dependent on b/L2 and the quality factor is dependent on hb1/2/L. Such different trends can be used to optimize device geometry and liquid property, thus maximizing quality factor and sensitivity in chemical sensing applications. Compared with microcantilevers in the 1st transverse mode, microcantilevers that vibrate in their first torsional mode have higher resonance frequency and quality factor. The increase in resonance frequency and quality factor results in higher sensitivity and reduced frequency noise, respectively. This will yield much lower limits of detection in liquid-phase chemical sensing applications.

Download or read book Resonant MEMS written by Oliver Brand and published by John Wiley & Sons. This book was released on 2015-04-22 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Part of the AMN book series, this book covers the principles, modeling and implementation as well as applications of resonant MEMS from a unified viewpoint. It starts out with the fundamental equations and phenomena that govern the behavior of resonant MEMS and then gives a detailed overview of their implementation in capacitive, piezoelectric, thermal and organic devices, complemented by chapters addressing the packaging of the devices and their stability. The last part of the book is devoted to the cutting-edge applications of resonant MEMS such as inertial, chemical and biosensors, fluid properties sensors, timing devices and energy harvesting systems.

Download or read book MEMS and Nanotechnology Volume 5 written by Gordon Shaw III and published by Springer Science & Business Media. This book was released on 2013-09-17 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: MEMS and Nanotechnology, Volume 5: Proceedings of the 2013 Annual Conference on Experimental and Applied Mechanics, the fifth volume of eight from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on a wide range of areas, including: Microelectronics Packaging Single Atom/Molecule Mechanical Testing MEMS Devices & Fabrication In-Situ Mechanical Testing Nanoindentation Experimental Analysis of Low-Dimensional Materials for Nanotechnology

Download or read book Theoretical Analysis of Dynamically Operating Polymer coated Microcantilever Chemical Sensors in a Viscous Liquid Medium written by Russell Cox and published by . This book was released on 2007 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Support Compliance on the Resonant Behavior of Microcantilever based Sensors in Viscous Fluids written by Rabin Maharjan and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Resonant microcantilevers are often considered for use in chemical sensing and biosensing applications. However, when excited in the conventional transverse flexural mode, their performance in liquids is severely compromised. Theoretical and experimental studies have shown that the detrimental effects of the liquid may be mitigated by operating the microcantilever in lateral flexure, especially for microbeams having smaller length-to-width (L/b) ratios. However, for these most promising geometries the predictions of existing models tend to diverge from experimental data for resonant frequency (fres) and quality factor (Q). A likely reason for these discrepancies is support compliance, which has been neglected in existing models. Thus, the derivation of an analytical model for the lateral-mode dynamic response of a microcantilever in a viscous fluid, including the effects of support compliance, is warranted and is the focus of this dissertation. Analytical solutions for natural frequency and Q are first obtained for the free-vibration case, followed by solutions for the forced-vibration response when the cantilever is excited by an imposed harmonic relative rotation near the support (simulating electrothermal actuation). Values of fres and Q are extracted from the response spectra for the tip deflection and the bending strain near the support. The support compliance (required as model input) is analytically related to device dimensions by employing dimensional analysis and 3-D FEA. The analytical results for the resonant characteristics are also related to sensor performance metrics (sensitivity and limit of detection), thus permitting one to exploit the potential of lateral-mode microcantilever-based liquid-phase sensors. The impact of support compliance, fluid resistance, and beam dimensions on the free- and forced-vibration response are explored, as are the differences associated with the two output signals. Comparisons of results with experimental data show a marked improvement over the previous rigid-support models for smaller L/b values. For the practical ranges of parameters considered the model indicates that, at smaller L/b values, support compliance may reduce Q by up to 1̃4% and fres and mass sensitivity (Sm) by up to 2̃1%. Conversely, for L/b>15 the support compliance effects are no more than 2% on Q and 4% on fres and Sm.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1972 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acoustic Wave Sensors written by D. S. Ballantine Jr. and published by Elsevier. This book was released on 1996-10-21 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by an interdisciplinary group of experts from both industry and academia, Acoustic Wave Sensors provides an in-depth look at the current state of acoustic wave devices and the scope of their use in chemical, biochemical, and physical measurements, as well as in engineering applications. Because of the inherent interdisciplinary applications of these devices, this book will be useful for the chemist and biochemist interested in the use and development ofthese sensors for specific applications; the electrical engineer involved in the design and improvement of these devices; the chemical engineer and the biotechnologist interested in using these devices for process monitoring and control; and the sensor community at large. - Provides in-depth comparison and analyses of different types of acoustic wave devices - Discusses operating principles and design considerations - Includes table of relevant material constants for quick reference - Presents an extensive review of current uses of these devices for chemical, biochemical, and physical measurements, and engineering applications

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Piezoelectric MEMS Resonators written by Harmeet Bhugra and published by Springer. This book was released on 2017-01-09 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces piezoelectric microelectromechanical (pMEMS) resonators to a broad audience by reviewing design techniques including use of finite element modeling, testing and qualification of resonators, and fabrication and large scale manufacturing techniques to help inspire future research and entrepreneurial activities in pMEMS. The authors discuss the most exciting developments in the area of materials and devices for the making of piezoelectric MEMS resonators, and offer direct examples of the technical challenges that need to be overcome in order to commercialize these types of devices. Some of the topics covered include: Widely-used piezoelectric materials, as well as materials in which there is emerging interest Principle of operation and design approaches for the making of flexural, contour-mode, thickness-mode, and shear-mode piezoelectric resonators, and examples of practical implementation of these devices Large scale manufacturing approaches, with a focus on the practical aspects associated with testing and qualification Examples of commercialization paths for piezoelectric MEMS resonators in the timing and the filter markets ...and more! The authors present industry and academic perspectives, making this book ideal for engineers, graduate students, and researchers.

Download or read book Feedback Systems written by Karl Johan Åström and published by Princeton University Press. This book was released on 2021-02-02 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The essential introduction to the principles and applications of feedback systems—now fully revised and expanded This textbook covers the mathematics needed to model, analyze, and design feedback systems. Now more user-friendly than ever, this revised and expanded edition of Feedback Systems is a one-volume resource for students and researchers in mathematics and engineering. It has applications across a range of disciplines that utilize feedback in physical, biological, information, and economic systems. Karl Åström and Richard Murray use techniques from physics, computer science, and operations research to introduce control-oriented modeling. They begin with state space tools for analysis and design, including stability of solutions, Lyapunov functions, reachability, state feedback observability, and estimators. The matrix exponential plays a central role in the analysis of linear control systems, allowing a concise development of many of the key concepts for this class of models. Åström and Murray then develop and explain tools in the frequency domain, including transfer functions, Nyquist analysis, PID control, frequency domain design, and robustness. Features a new chapter on design principles and tools, illustrating the types of problems that can be solved using feedback Includes a new chapter on fundamental limits and new material on the Routh-Hurwitz criterion and root locus plots Provides exercises at the end of every chapter Comes with an electronic solutions manual An ideal textbook for undergraduate and graduate students Indispensable for researchers seeking a self-contained resource on control theory

Download or read book Microscale Acoustofluidics written by Thomas Laurell and published by Royal Society of Chemistry. This book was released on 2014-12-08 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: The manipulation of cells and microparticles within microfluidic systems using external forces is valuable for many microscale analytical and bioanalytical applications. Acoustofluidics is the ultrasound-based external forcing of microparticles with microfluidic systems. It has gained much interest because it allows for the simple label-free separation of microparticles based on their mechanical properties without affecting the microparticles themselves. Microscale Acoustofluidics provides an introduction to the field providing the background to the fundamental physics including chapters on governing equations in microfluidics and perturbation theory and ultrasound resonances, acoustic radiation force on small particles, continuum mechanics for ultrasonic particle manipulation, and piezoelectricity and application to the excitation of acoustic fields for ultrasonic particle manipulation. The book also provides information on the design and characterization of ultrasonic particle manipulation devices as well as applications in acoustic trapping and immunoassays. Written by leading experts in the field, the book will appeal to postgraduate students and researchers interested in microfluidics and lab-on-a-chip applications.

Download or read book The Shock Absorber Handbook written by John C. Dixon and published by John Wiley & Sons. This book was released on 2008-02-28 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Every one of the many millions of cars manufactured annually worldwide uses shock absorbers, otherwise known as dampers. These form a vital part of the suspension system of any vehicle, essential for optimizing road holding, performance and safety. This, the second edition of the Shock Absorber Handbook (first edition published in 1999), remains the only English language book devoted to the subject. Comprehensive coverage of design, testing, installation and use of the damper has led to the book's acceptance as the authoritative text on the automotive applications of shock absorbers. In this second edition, the author presents a thorough revision of his book to bring it completely up to date. There are numerous detail improvements, and extensive new material has been added particularly on the many varieties of valve design in the conventional hydraulic damper, and on modern developments such as electrorheological and magnetorheological dampers. "The Shock Absorber Handbook, 2nd Edition" provides a thorough treatment of the issues surrounding the design and selection of shock absorbers. It is an invaluable handbook for those working in industry, as well as a principal reference text for students of mechanical and automotive engineering.

Download or read book Handbook of Modern Sensors written by Jacob Fraden and published by Springer Science & Business Media. This book was released on 2006-04-29 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seven years have passed since the publication of the previous edition of this book. During that time, sensor technologies have made a remarkable leap forward. The sensitivity of the sensors became higher, the dimensions became smaller, the sel- tivity became better, and the prices became lower. What have not changed are the fundamental principles of the sensor design. They are still governed by the laws of Nature. Arguably one of the greatest geniuses who ever lived, Leonardo Da Vinci, had his own peculiar way of praying. He was saying, “Oh Lord, thanks for Thou do not violate your own laws. ” It is comforting indeed that the laws of Nature do not change as time goes by; it is just our appreciation of them that is being re?ned. Thus, this new edition examines the same good old laws of Nature that are employed in the designs of various sensors. This has not changed much since the previous edition. Yet, the sections that describe the practical designs are revised substantially. Recent ideas and developments have been added, and less important and nonessential designs were dropped. Probably the most dramatic recent progress in the sensor technologies relates to wide use of MEMS and MEOMS (micro-electro-mechanical systems and micro-electro-opto-mechanical systems). These are examined in this new edition with greater detail. This book is about devices commonly called sensors. The invention of a - croprocessor has brought highly sophisticated instruments into our everyday lives.

Download or read book Analysis and Design Principles of MEMS Devices written by Minhang Bao and published by Elsevier. This book was released on 2005-04-12 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sensors and actuators are now part of our everyday life and appear in many appliances, such as cars, vending machines and washing machines. MEMS (Micro Electro Mechanical Systems) are micro systems consisting of micro mechanical sensors, actuators and micro electronic circuits. A variety of MEMS devices have been developed and many mass produced, but the information on these is widely dispersed in the literature. This book presents the analysis and design principles of MEMS devices. The information is comprehensive, focusing on microdynamics, such as the mechanics of beam and diaphragm structures, air damping and its effect on the motion of mechanical structures. Using practical examples, the author examines problems associated with analysis and design, and solutions are included at the back of the book. The ideal advanced level textbook for graduates, Analysis and Design Principles of MEMS Devices is a suitable source of reference for researchers and engineers in the field.* Presents the analysis and design principles of MEMS devices more systematically than ever before.* Includes the theories essential for the analysis and design of MEMS includes the dynamics of micro mechanical structures* A problem section is included at the end of each chapter with answers provided at the end of the book.