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Статті в журналах з теми "Mechanical mode sensing":

1

Lee, Jin-Hyuk. "Biomimetic idealization of a mechanically coupled acoustic sound sensing mechanism." SIMULATION 94, no. 2 (June 15, 2017): 131–43. http://dx.doi.org/10.1177/0037549717712038.

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This paper presents the idealization of a mechanically coupled acoustic sensor mechanism for directivity with the use of polysilicon, which has ideal mechanical and electrical material properties in terms of micro-fabrication. A mathematical model related to mechanical sensitivity is developed as a function of the material properties and geometry of the sensor, which evaluates the characteristics of a two-degree-of-freedom-based lumped parameter model. A challenge in such a study is that the model needs to be simple but sufficiently sophisticated to capture the characteristics of the sensor mechanism. Eigen modes and frequencies of the mechanically coupled acoustic sensor mechanism are determined by an energy method using mode functions applicable to the complete system that are from admissible the mode functions chosen for the component elements of the system. The synthesis is accomplished by using equations of constraint that follow conditions imposed by force equilibrium and deflection compatibility at the junctions. Finally, the results are compared with those obtained by a full-scale finite element model developed in a commercial software package. The predicted first and second natural frequencies differed by less than 10% and 3%, respectively, in all test cases.
2

Xia, Ji, Qifeng Qiao, Guangcan Zhou, Fook Siong Chau, and Guangya Zhou. "Opto-Mechanical Photonic Crystal Cavities for Sensing Application." Applied Sciences 10, no. 20 (October 12, 2020): 7080. http://dx.doi.org/10.3390/app10207080.

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A new class of hybrid systems that couple optical and mechanical nanoscale devices is under development. According to their interaction concepts, two groups of opto-mechanical systems are summarized as mechanically tunable and radiation pressure-driven optical resonators. On account of their high-quality factors and small mode volumes as well as good on-chip integrability with waveguides/circuits, photonic crystal (PhC) cavities have attracted great attention in sensing applications. Benefitting from the opto-mechanical interaction, a PhC cavity integrated opto-mechanical system provides an attractive platform for ultrasensitive sensors to detect displacement, mass, force, and acceleration. In this review, we introduce basic physical concepts of opto-mechanical PhC system and describe typical experimental systems for sensing applications. Opto-mechanical interaction-based PhC cavities offer unprecedented opportunities to develop lab-on-a-chip devices and witness a promising prospect to further manipulate light propagation in the nanophotonics.
3

Novotný, Vít, Petr Sysel, Aleš Prokeš, Pavel Hanák, Karel Slavíček, and Jiří Přinosil. "Fiber Optic Based Distributed Mechanical Vibration Sensing." Sensors 21, no. 14 (July 13, 2021): 4779. http://dx.doi.org/10.3390/s21144779.

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The distributed long-range sensing system, using the standard telecommunication single-mode optical fiber for the distributed sensing of mechanical vibrations, is described. Various events generating vibrations, such as a walking or running person, moving car, train, and many other vibration sources, can be detected, localized, and classified. The sensor is based on phase-sensitive optical time-domain reflectometry (ϕ-OTDR). Related sensing system components were designed and constructed, and the system was tested both in the laboratory and in the real deployment, with an 88 km telecom optical link, and the results are presented in this paper. A two-fiber sensor unit, with a double-sensing range was also designed, and its scheme is described. The unit was constructed and the initial measurement results are presented.
4

Quanyi, Hu, Zhang Hong, Tian Shujun, and Qin Xuxin. "Performances analysis of a novel load-sensing hydraulic system with overriding differential pressure control." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 23 (September 3, 2016): 4331–43. http://dx.doi.org/10.1177/0954406216667760.

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The traditional load-sensing hydraulic system is an energy-saving fluid power transmission, which supply “on-demand” flow at a prescribed pressure margin greater than the highest load pressure of the system. In this paper, a novel load-sensing system that has a variable pressure margin through overriding differential pressure control via integrating an electro-proportional three-way type pressure reducing valve into the hydro-mechanical load-sensing valve is proposed. Also, a bond graph model taking into account the dynamic characteristics of load-sensing valve and load-sensing path is constructed, and three group experiments are performed to verify the validation of the model. Based on the bond graph model, a series of theoretical simulations are carried out to prove that the proposed Load-Sensing system enables a satisfactory balance between energy efficiency and rapid dynamic response over a wide range of operating conditions. In addition, due to overriding differential pressure control, mode selection and power limit regulation can also be achieved.
5

Kan, Wenqing, Ying Huang, Xiao Zeng, Xiaohui Guo, and Ping Liu. "A dual-mode proximity sensor with combination of inductive and capacitive sensing units." Sensor Review 38, no. 2 (March 19, 2018): 199–206. http://dx.doi.org/10.1108/sr-06-2017-0111.

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Purpose The purpose of this paper is to present a dual-mode proximity sensor composed of inductive and capacitive sensing modes, which can help the robot distinguish different objects and obtain distance information at the same time. A systematic study of sensor response to various objects and the function of cooperation sensing is needed. Furthermore, the application in the field of robotic area needs to be discussed. Design/methodology/approach Numerical modeling of each sensing modes and simulations based on finite element analysis method has been carried out to verify the designed dual-mode sensor. A number of objects composed of different materials are used to research the cooperation perception and proximity sensing functions. In addition, the proposed sensor is used on the palm of a mechanical hand as application experiment. Findings The characteristics of the sensor are summarized as follows: the sensing range of inductive mode is 0-5.6 mm for detecting a copper block and the perceive range of capacitive mode is 0-5.1 mm for detecting a plastic block. The collaborative perceive tests validated that the non-ferromagnetism metals can be distinguished by inductive mode. Correspondingly, ferromagnetism metals and dielectric objects are differentiated by capacitive mode. Application experiments results reveal that both plastic bottle and steel bottle could be detected and differentiated. The experimental results are in agreement with those of simulations. Originality value This paper provides a study of dual-mode proximity sensor in terms of design, experiments and application.
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Yin, Rui, Rui Wang, Xiang Yang Zhou, Xiang Yang Peng, and Ke Wang. "Dynamic Modeling and Nonlinear Decoupling Control of Inertial Stabilized Platform for Aerial Remote Sensing System." Advanced Materials Research 898 (February 2014): 807–13. http://dx.doi.org/10.4028/www.scientific.net/amr.898.807.

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The mutual coupling between the motion of three frames exists when inertial stabilized platform (ISP) for aerial remote sensing system is working, due to the mechanical character of the stabilized platform. Based on Lagrange mechanics and starting from analytical mechanics, a kinetics model of inertial stabilized platform is developed for analyzing the complex coupling relation. On the basis of the model, a nonlinear decoupling control method using sliding mode control (SMC) is designed for rolling and pitching frames after coupling moment being taken for external disturbance. While, for azimuth frame, which can not directly adopt sliding mode control method, a novel method of introducing a judgment factor and combining SMC and PID is provided. Compared with PID method, the simulation results show that the overshoot of the system is reduced obviously and the decoupling effect is better. Results obtained will be a theoretical foundation for the further study of inertial stabilized platform, and guarantee high precision to stabilized platform system.
7

La Gala, Giada, John P Mathew, Pascal Neveu, and Ewold Verhagen. "Nanomechanical design strategy for single-mode optomechanical measurement." Journal of Physics D: Applied Physics 55, no. 22 (March 3, 2022): 225101. http://dx.doi.org/10.1088/1361-6463/ac569d.

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Abstract The motion of a mechanical resonator is intrinsically decomposed over a collection of normal modes of vibration. When the resonator is used as a sensor, its multimode nature often deteriorates or limits its performance and sensitivity. This challenge is frequently encountered in state-of-the-art optomechanical sensing platforms. We present a mechanical design strategy that ensures that optomechanical measurements can retrieve information on a single mechanical degree of freedom, and implement it in a sliced photonic crystal nanobeam resonator. A spectral design approach is used to make mechanical symmetries robust against practical disorder. The effectiveness of the method is evaluated by deriving a relevant figure of merit for continuous and pulsed measurement application scenarios. The method can be employed in any mechanical design that presents unwanted spurious mechanical modes. In the nanobeam platform, we experimentally show an increase of the signal to noise ratio of the mode of interest over the first spurious mode by four orders of magnitudes.
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Zhao, Xuyang, Zhihe Guo, Yi Zhou, Junhong Guo, Zhiran Liu, Yuxiang Li, Man Luo, and Xiang Wu. "Optical Whispering-Gallery-Mode Microbubble Sensors." Micromachines 13, no. 4 (April 9, 2022): 592. http://dx.doi.org/10.3390/mi13040592.

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Whispering-gallery-mode (WGM) microbubble resonators are ideal optical sensors due to their high quality factor, small mode volume, high optical energy density, and geometry/design/structure (i.e., hollow microfluidic channels). When used in combination with microfluidic technologies, WGM microbubble resonators can be applied in chemical and biological sensing due to strong light–matter interactions. The detection of ultra-low concentrations over a large dynamic range is possible due to their high sensitivity, which has significance for environmental monitoring and applications in life-science. Furthermore, WGM microbubble resonators have also been widely used for physical sensing, such as to detect changes in temperature, stress, pressure, flow rate, magnetic field and ultrasound. In this article, we systematically review and summarize the sensing mechanisms, fabrication and packing methods, and various applications of optofluidic WGM microbubble resonators. The challenges of rapid production and practical applications of WGM microbubble resonators are also discussed.
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Ng, T. W., and S. Thirunavukkarasu. "Optical Sensing Limits in Contact and Bending Mode Atomic Force Microscopy." Experimental Mechanics 47, no. 6 (March 9, 2007): 841–44. http://dx.doi.org/10.1007/s11340-007-9044-x.

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Zhang, Rui, Ran Guo, and Shiyue Wang. "Mixed mode fracture study of PMMA using digital gradient sensing method." Engineering Fracture Mechanics 119 (March 2014): 164–72. http://dx.doi.org/10.1016/j.engfracmech.2014.02.020.

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Дисертації з теми "Mechanical mode sensing":

1

Liu, Zhen. "Reconstruction and Control of Tip Position and Dynamic Sensing of Interaction Force for Micro-Cantilever to Enable High Speed and High Resolution Dynamic Atomic Force Microscopy." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483629656167247.

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Harder, Thomas. "Atténuation des instabilités paramétriques basée sur la pression de radiation dans les détecteurs d’ondes gravitationnelles." Thesis, Université Côte d'Azur, 2022. http://www.theses.fr/2022COAZ4005.

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La première détection directe des ondes gravitationnelles (OG) a eu lieu en 2015 grâce aux interféromètres, interféromètre de type Michelson à recyclage possédant des cavités Fabry Perot de plusieurs km de longueur dans les bras. Ces cavités permettent une puissance optique élevée, nécessaire pour réduire le bruit de grenaille des détecteurs. Une instabilité paramétrique (IP) est un phénomène optomécanique non linéaire qui transfère une partie de l’énergie du faisceau à un mode propre d’un miroir et à un mode optique d’ordre élevé dont les amplitudes croissent de façon exponentielle. Sans atténuation, l’instabilité fait perdre le contrôle de l’interféromètre.Différentes stratégies d’atténuation les IP ont été proposées et ont été intégrées dans les détecteurs qui ont pu ainsi fonctionner jusqu’au niveau actuel de puissance optique. Pour les détecteurs de prochaine génération, une augmentation de sensibilité d’un facteur dix est visée par rapport aux détecteurs actuels. Une manière d’atteindre ce but consiste à augmenter la puissance optique dans les cavités des bras. Cette augmentation pourrait impliquer plus d’IP, plus difficiles à atténuer.Dans cette thèse nous proposons une méthode active et flexible d’atténuation des IP, qui utilise la pression de radiation d’un faisceau laser dédié. L’idée est d’appliquer une contre pression sur plusieurs points du miroir grâce à un petit faisceau laser, avec des fréquences de dizaine de kHz. A cette fin, la déflection rapide du faisceau est requise. Par ailleurs, il faut être capable de détecter les IP dès leur naissance, au niveau de l’excitation thermique.Cette thèse présente les premières études expérimentales d’un tel système : la déflection rapide basée sur des modulateurs acousto-optiques est explorée. Une fréquence de déflection de 10 MHz en 2D est démontrée. La puissance optique maximale du faisceau dévié est 3,6 W, ce qui correspond à une force de pression de radiation de 24 nN. Ces caractéristiques remplissent les conditions nécessaires.La détection des modes mécaniques d’un miroir est étudiée à l’aide d’un system utilisant un interféromètre de Michelson. La sensibilité obtenue pour un faisceau en position fixe sur le miroir correspond à un changement de longueur de bras de δL = 4.8 · 10^-14 m/√Hz. Cette valeur est environ un ordre de grandeur plus élevée que le déplacement de la surface du miroir due à l’excitation thermique des modes mécaniques. Des propositions sont données pour améliorer la sensibilité de l’interféromètre et pour utiliser ce système pour étudier l’atténuation active des modes propre d’un miroir par la pression de radiation
Direct detection of Gravitational Waves was demonstrated for the first time in 2015 with km-scale Michelson interferometers. In order to reduce the shot noise at high frequency of these detectors high optical power in the arm cavities is needed. At that high circulating power a nonlinear optomechanical phenomenon called parametric instability (PI) may occur that induce the amplification of mirror’s eigenmodes. It limits the optical power and can cause the loss of the interferometer’s control if notmitigated.Several PI mitigation strategies have been proposed and already implemented in current gravitational wave detectors. These schemes keep them working without PI at the current optical power level in the cavities but they are not adapted to PI involving any kind of mechanical mirror modes, which needs to be considered when the optical circulation power is increased further. Next generation detectors aim at increasing their sensitivity of a factor of ten compared to current detectors. This can be achieved, inter alia, through the increase of the optical power in the arm cavities which will imply more PI.In this thesis an active and flexible PI mitigation strategy based on radiation pressure of a movable laser beam is proposed. The idea is to apply a damping force to mitigate PI. Fast beam steering is required to point at different positions of the cavity mirror with a small laser spot during one period of the mechanical mode with frequencies in the kHz-range. A sensitive sensing method is required to detect PI at the level ofthermal excitation.First experimental studies of a table-top setup are presented: rapid beam deflection based on acousto-optic modulators is investigated. A final configuration with 2D arbitrary beam steering with a maximal deflection rate of 10 MHz is demonstrated for a maximal optical power of 3.6 W, corresponding to a radiation pressure force of 24 nN. It satisfies the requirements of the laser beam that should be used as radiation pressure force for our proposed PI damping scheme.Sensing of mechanical mirror modes is investigated with the 2D beam steering system based on a Michelson interferometer. A sensitivity corresponding to a differential arm length change of δL = 4.8 · 10^-14 m/√Hz is achieved for a fixed beam position on the mirror. It is around one order of magnitude higher than the expected displacement of the mirror due to thermally excited mirror modes. Propositions are given to improve the sensitivity of the interferometer and to use the same setup to investigate active damping of mirror modes via radiation pressure
3

Killough, Brian D. "A semi-empirical cellular automata model for wildfire monitoring from a geosynchronous space platform." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539623419.

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The environmental and human impacts of wildfires have grown considerably in recent years due to an increase in their frequency and coverage. Effective wildfire management and suppression requires real-time data to locate fire fronts, model their propagation and assess the impact of biomass burning. Existing empirical wildfire models are based on fuel properties and meteorological data with inadequate spatial or temporal sampling. A geosynchronous space platform with the proposed set of high resolution infrared detectors provides a unique capability to monitor fires at improved spatial and temporal resolutions. The proposed system is feasible with state-of-the-art hardware and software for high sensitivity fire detection at saturation levels exceeding active flame temperatures. Ground resolutions of 100 meters per pixel can be achieved with repeat cycles less than one minute. Atmospheric transmission in the presence of clouds and smoke is considered. Modeling results suggest fire detection is possible through thin clouds and smoke. A semi-empirical cellular automata model based on theoretical elliptical spread shapes is introduced to predict wildfire propagation using detected fire front location and spread rate. Model accuracy compares favorably with real fire events and correlates within 2% of theoretical ellipse shapes. This propagation modeling approach could replace existing operational systems based on complex partial differential equations. The baseline geosynchronous fire detection system supplemented with a discrete-based propagation model has the potential to save lives and property in the otherwise uncertain and complex field of fire management.
4

Manifacier, Ian. "Understanding adherent cell mechanics and the influence of substrate rigidity." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4106/document.

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L’ingénierie tissulaire est une stratégie médicale qui repose sur la régénération de tissu par les cellules avec ou sans matériaux. Pour maîtriser cette synthèse, il faut comprendre la cellule comme une part intégrante du tissu. Hormis ses interactions biochimiques avec son support, la cellule interagit également mécaniquement avec son environnement. Elle s’accroche à ce dernier et évalue sa dureté pour adapter sa réponse biologique. Dans cette étude, j’ai développé des modèles numériques pour analyser l’influence de la rigidité du substrat sur le comportement mécanique de la cellule, sur sa structure contractile interne et les efforts qu’elle génère. En d’autres termes, j’ai essayé de comprendre comment la cellule ressent la rigidité de son environnement. De plus, au lieu de me focaliser sur les propriétés mécaniques quantitatives, j’ai cherché à développer un modèle conceptuel simplifié plus proche de la structure cellulaire
Tissue engineering is a medical strategy based on utilizing cells and materials to regenerate a new tissue. Yet, it involves intertwined interactions that allow cells to act as integrated parts of an organ. In addition to chemical reactions, the cell interacts mechanically with its environment by sensing its rigidity. Here, we used several computational models to understand how substrate rigidity affects a cell’s structure as it adheres and spreads on it. In other words we tried to understand the way a cell feels how soft or hard it surrounding is, how it affects its internal structure and the forces that transit within it. In addition, instead of focusing on mechanical properties, we developed a simplified, yet coherent conceptual understanding of the cellular structure
5

Long, Fei. "Three-Dimensional Motion Control and Dynamic Force Sensing of a Magnetically Propelled Micro Particle Using a Hexapole Magnetic Actuator." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452093964.

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6

Seoudi, Tarek. "Non-intrusive CdSe-based quantum dots for sensing pressure and temperature in lubricated contacts." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI009.

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Cette thèse est dédiée à la mesure des pressions et des températures locales et à la comparaison de la génération de chaleur dans les contacts élastohydrodynamiques (EHD) de type tout acier et hybride (nitrure de silicium-acier). Le but ultime de ce travail est de développer une nouvelle technique in situ non-intrusive, exploitant la sensibilité de la photoluminescence (PL) des boîtes quantiques (QDs) de CdSe/CdS/ZnS aux variations de pression et température, afin de cartographier ces deux paramètres dans les contacts EHD. Dispersible à faible concentration dans les lubrifiants, il est montré que les QDs ne modifient pas le comportement rhéologique du fluide porteur et que le cisaillement n’est pas perturbateur à la réponse en PL. La calibration des QDs en suspension confirme la dépendance de la réponse en PL des QDs à la pression et à la température. Les mesures in situ sont effectuées en utilisant un banc d’essai bille-disque. La comparaison entre les mesures in situ de pression et de température et celles prédites à l'aide d'un modèle éléments finis TEHD interne montre une bonne concordance, ce qui démontre la faisabilité de la méthodologie proposée. Les effets du glissement et du chargement normal sur la pression, la température et la chaleur générée sont reportés. L’effet des propriétés thermiques des solides est souligné et la répartition de la chaleur générée entre les solides en contact est étudiée. L'équilibre énergétique entre l'énergie mécanique et l'énergie thermique interne générée par compression et cisaillement est démontré en comparant les pertes de puissance expérimentales et la chaleur générée issue du modèle numérique, pour des contacts acier-acier et hybrides
This thesis is dedicated to the measurement of local pressure and temperature and to compare the heat generation in all-steel and silicon nitride-steel (hybrid) elastohydrodynamic (EHD) contacts. The ultimate goal of this work is to develop a new non-intrusive in situ technique, exploiting the sensitivity of the photoluminescence (PL) of CdSe/CdS/ZnS quantum dots (QDs) to pressure and temperature. Dispersible in small concentration in lubricants, it is shown that the QDs doesn’t modify the rheological behavior of the carrier fluid and that shearing is not perturbative to the QDs PL response. The calibration of QDs in the suspension confirms the QDs PL dependence on temperature and pressure. The in situ measurements were conducted in EHD contacts using a ball-on-disc test rig. Comparisons between pressure and temperature measurements and predictions, using an in–house finite element thermal EHD model, showed a good agreement which demonstrates the feasibility of the proposed methodology. The effects of sliding and normal loading on pressure, temperature and heat generation are indicated. The effect of the thermal properties of the solid materials is underlined and the partition of the generated heat between the contacting solids is investigated. The energy equilibrium between the mechanical energy and the internal thermal energy generated by compression and shearing is demonstrated by comparing experimental power losses and numerical heat generation, in steel-steel and hybrid contacts
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Zhang, Zhipeng. "MAGNETIC TWEEZERS: ACTUATION, MEASUREMENT, AND CONTROL AT NANOMETER SCALE." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1243885884.

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8

"Dynamic across time autonomous-sensing, interpretation, model learning and maintenance theory." Tulane University, 1994.

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A formal theory for the development of a generic model of an autonomous sensor is proposed and implemented. An autonomous sensor not only interprets the acquired data in accordance with an embedded expert system knowledge base but also uses it to modify and enhance the knowledge base. The main objective of the model is to combine the capabilities of the physical sensor and an expert operator monitoring the sensor in real-time. This gives the sensor the capabilities of not only sensing the measurand, but also interpreting the sensed data at a higher human-like level, maintaining its databases over time to account for bad or incomplete data, and learning about the measurand and sensor behaviors. The sensor's data base is defined as the quantitative data it senses as well as the qualitative data it interprets. Its knowledge base is defined as the rules that allow maintenance of the truth and integrity of the system and methodologies for model learning. Relevant aspects of the system are described by properties and their qualitative measure called states. A set of properties and their state values define a concept, and a set of consecutively occurring concepts, over time, describe behaviors that essentially provide a qualitative view of the different possible states of the system. These behaviors and associated concepts, called envisionments, are used to identify the measurand and sensor behaviors in real-time so as to take appropriate countermeasures for those behaviors that cause problems. The identification process is called interpretation and is similar to the pattern recognition problem. Dynamic Across Time Autonomous - Sensing, Interpretation, Model Learning And Maintenance Theory (DATA-SIMLAMT) is a novel theory in the field of robotics and artificial intelligence that attempts to model computer reasoning on human-like reasoning about system behaviors. It finds applications in any field that incorporates the human in the control system. Autonomous sensing is just one application of this theory
acase@tulane.edu
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"Model Agnostic Extreme Sub-pixel Visual Measurement and Optimal Characterization." Master's thesis, 2012. http://hdl.handle.net/2286/R.I.15110.

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abstract: It is possible in a properly controlled environment, such as industrial metrology, to make significant headway into the non-industrial constraints on image-based position measurement using the techniques of image registration and achieve repeatable feature measurements on the order of 0.3% of a pixel, or about an order of magnitude improvement on conventional real-world performance. These measurements are then used as inputs for a model optimal, model agnostic, smoothing for calibration of a laser scribe and online tracking of velocimeter using video input. Using appropriate smooth interpolation to increase effective sample density can reduce uncertainty and improve estimates. Use of the proper negative offset of the template function has the result of creating a convolution with higher local curvature than either template of target function which allows improved center-finding. Using the Akaike Information Criterion with a smoothing spline function it is possible to perform a model-optimal smooth on scalar measurements without knowing the underlying model and to determine the function describing the uncertainty in that optimal smooth. An example of empiric derivation of the parameters for a rudimentary Kalman Filter from this is then provided, and tested. Using the techniques of Exploratory Data Analysis and the "Formulize" genetic algorithm tool to convert the spline models into more accessible analytic forms resulted in stable, properly generalized, KF with performance and simplicity that exceeds "textbook" implementations thereof. Validation of the measurement includes that, in analytic case, it led to arbitrary precision in measurement of feature; in reasonable test case using the methods proposed, a reasonable and consistent maximum error of around 0.3% the length of a pixel was achieved and in practice using pixels that were 700nm in size feature position was located to within ± 2 nm. Robust applicability is demonstrated by the measurement of indicator position for a King model 2-32-G-042 rotameter.
Dissertation/Thesis
Measurement Results (part 1)
Measurement Results (part 2)
General Presentation
M.S. Mechanical Engineering 2012
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(9976460), Xu Zhang. "Model-based co-design of sensing and control systems for turbo-charged, EGR-utilizing spark-ignited engines." Thesis, 2021.

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Анотація:
Stoichiometric air-fuel ratio (AFR) and air/EGR flow control are essential control problems in today’s advanced spark-ignited (SI) engines to enable effective application of the three-way-catalyst (TWC) and generation of required torque. External exhaust gas recirculation (EGR) can be used in SI engines to help mitigate knock, reduce enrichment and improve efficiency[1 ]. However, the introduction of the EGR system increases the complexity of stoichiometric engine-out lambda and torque management, particularly for high BMEP commercial vehicle applications. This thesis develops advanced frameworks for sensing and control architecture designs to enable robust air handling system management, stoichiometric cylinder air-fuel ratio (AFR) control and three-way-catalyst emission control.

The first work in this thesis derives a physically-based, control-oriented model for turbocharged SI engines utilizing cooled EGR and flexible VVA systems. The model includes the impacts of modulation to any combination of 11 actuators, including the throttle valve, bypass valve, fuel injection rate, waste-gate, high-pressure (HP) EGR, low-pressure (LP) EGR, number of firing cylinders, intake and exhaust valve opening and closing timings. A new cylinder-out gas composition estimation method, based on the inputs’ information of cylinder charge flow, injected fuel amount, residual gas mass and intake gas compositions, is proposed in this model. This method can be implemented in the control-oriented model as a critical input for estimating the exhaust manifold gas compositions. A new flow-based turbine-out pressure modeling strategy is also proposed in this thesis as a necessary input to estimate the LP EGR flow rate. Incorporated with these two sub-models, the control-oriented model is capable to capture the dynamics of pressure, temperature and gas compositions in manifolds and the cylinder. Thirteen physical parameters, including intake, boost and exhaust manifolds’ pressures, temperatures, unburnt and burnt mass fractions as well as the turbocharger speed, are defined as state variables. The outputs such as flow rates and AFR are modeled as functions of selected states and inputs. The control-oriented model is validated with a high fidelity SI engine GT-Power model for different operating conditions. The novelty in this physical modeling work includes the development and incorporation of the cylinder-out gas composition estimation method and the turbine-out pressure model in the control-oriented model.

The second part of the work outlines a novel sensor selection and observer design algorithm for linear time-invariant systems with both process and measurement noise based on H2 optimization to optimize the tradeoff between the observer error and the number of required sensors. The optimization problem is relaxed to a sequence of convex optimization problems that minimize the cost function consisting of the H2 norm of the observer error and the weighted l1 norm of the observer gain. An LMI formulation allows for efficient solution via semi-definite programing. The approach is applied here, for the first time, to a turbo-charged spark-ignited (SI) engine using exhaust gas recirculation to determine the optimal sensor sets for real-time intake manifold burnt gas mass fraction estimation. Simulation with the candidate estimator embedded in a high fidelity engine GT-Power model demonstrates that the optimal sensor sets selected using this algorithm have the best H2 estimation performance. Sensor redundancy is also analyzed based on the algorithm results. This algorithm is applicable for any type of modern internal combustion engines to reduce system design time and experimental efforts typically required for selecting optimal sensor sets.

The third study develops a model-based sensor selection and controller design framework for robust control of air-fuel-ratio (AFR), air flow and EGR flow for turbocharged stoichiometric engines using low pressure EGR, waste-gate turbo-charging, intake throttling and variable valve timing. Model uncertainties, disturbances, transport delays, sensor and actuator characteristics are considered in this framework. Based on the required control performance and candidate sensor sets, the framework synthesizes an H1 feedback controller and evaluates the viability of the candidate sensor set through analysis of the structured
singular value μ of the closed-loop system in the frequency domain. The framework can also be used to understand if relaxing the controller performance requirements enables the use of a simpler (less costly) sensor set. The sensor selection and controller co-design approach is applied here, for the first time, to turbo-charged engines using exhaust gas circulation. High fidelity GT-Power simulations are used to validate the approach. The novelty of the work in this part can be summarized as follows: (1) A novel control strategy is proposed for the stoichiometric SI engines using low pressure EGR to simultaneously satisfy both the AFR and air/EGR-path control performance requirements; (2) A parametrical method to simultaneously select the sensors and design the controller is first proposed for the internal combustion engines.

In the fourth part of the work, a novel two-loop estimation and control strategy is proposed to reduce the emission of the three-way-catalyst (TWC). In the outer loop, an FOS estimator consisting of a TWC model and an extended Kalman-filter is used to estimate the current TWC fractional oxygen state (FOS) and a robust controller is used to control the TWC FOS by manipulating the desired engine λ. The outer loop estimator and controller are combined with an existing inner loop controller. The inner loop controller controls the engine λ based on the desired λ value and the control inaccuracies are considered and compensated by the outer loop robust controller. This control strategy achieves good emission reduction performance and has advantages over the constant λ control strategy and the conventional two-loop switch-type control strategy.

Книги з теми "Mechanical mode sensing":

1

Martinec, J. Snowmelt runoff model (SRM) user's manual. Bern: Dept. of Geography, University of Bern, 1994.

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2

Martinec, J. Snow melt runoff model (SRM) : user's manual. Bern: Dept. of Geography, University of Berne, 1998.

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3

Forrest, Stephen R. Organic Electronics. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198529729.001.0001.

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Organic electronics is a platform for very low cost and high performance optoelectronic and electronic devices that cover large areas, are lightweight, and can be both flexible and conformable to irregularly shaped surfaces such as foldable smart phones. Organics are at the core of the global organic light emitting device (OLED) display industry, and also having use in efficient lighting sources, solar cells, and thin film transistors useful in medical and a range of other sensing, memory and logic applications. This book introduces the theoretical foundations and practical realization of devices in organic electronics. It is a product of both one and two semester courses that have been taught over a period of more than two decades. The target audiences are students at all levels of graduate studies, highly motivated senior undergraduates, and practicing engineers and scientists. The book is divided into two sections. Part I, Foundations, lays down the fundamental principles of the field of organic electronics. It is assumed that the reader has an elementary knowledge of quantum mechanics, and electricity and magnetism. Background knowledge of organic chemistry is not required. Part II, Applications, focuses on organic electronic devices. It begins with a discussion of organic thin film deposition and patterning, followed by chapters on organic light emitters, detectors, and thin film transistors. The last chapter describes several devices and phenomena that are not covered in the previous chapters, since they lie outside of the current mainstream of the field, but are nevertheless important.

Частини книг з теми "Mechanical mode sensing":

1

Jain, Amith S., and Hareesh V. Tippur. "Reflection-Mode Digital Gradient Sensing Technique for Experimental Fracture Mechanics." In Fracture, Fatigue, Failure and Damage Evolution, Volume 8, 1–7. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-21611-9_1.

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2

Oh, Il Kweon, Seong Won Yeom, and Dong Weon Lee. "Modal Reduced Order Model for Vision Sensing of IPMC Actuator." In Experimental Mechanics in Nano and Biotechnology, 1523–26. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-415-4.1523.

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3

Mohan, Sagar, and Atanu Banerjee. "Exploring Self-Sensing Behaviour of Shape Memory Alloy Using Kalman Filters Based on Boyd and Lagoudas Model." In Lecture Notes in Mechanical Engineering, 121–30. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-6738-1_10.

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4

Moye, Melinda J., and Alison L. O’Malley. "Mechanics of Survey Data Analysis." In Employee Surveys and Sensing, 239–53. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190939717.003.0015.

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In this chapter the authors outline important issues to consider when setting up a survey so that the administration team or a third party vendor is able to conduct meaningful analyses afterward. They discuss decisions surrounding data structure, confidential versus anonymous surveys, and missing data and reporting elements. They also discuss understanding variability, item history, and using norms and benchmark data. The latter part of the chapter focuses on model-building. In summary, it is critical to establish a purpose for a survey and to have a clear strategy for data analysis at the outset to facilitate leaders’ understanding of the data and their ability to act afterward.
5

Feng, Bo, Dario J. Pasadas, Artur L. Ribeiro, and Helena G. Ramos. "Eddy Current Testing of the Lightning Strike Protection Layer in Aerospace Composite Structures." In Studies in Applied Electromagnetics and Mechanics. IOS Press, 2020. http://dx.doi.org/10.3233/saem200004.

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The lightning strike protection layer, which is a mesh of metal stripes, is adhered to composite materials to dissipate the huge current induced during lightning strike. This paper presents an eddy current imaging method to inspect defects in the lightning strike protection layer. A tuning method was applied to tune the resonant frequency of excitation and sensing coils and enhance the testing results. Two parameters, namely the amplitude of induced voltage in the sensing coil and the amplitude of the voltage across a sampling resistor in the excitation circuit, were used to image the defects. The results show that the image formed by sensing coil voltage is less noisy and more accurate.
6

Azize, Joseph. "The Clear Impressions Exercise." In Gurdjieff, 261–70. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190064075.003.0017.

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This exercise was taught by George Adie. It is almost certainly an otherwise unknown example of Gurdjieff’s Transformed-contemplation, being referred to in nothing which has previously been published. It was given as an exercise to help one come to a sense of one’s own being, reality, and presence by looking about one while sensing parts of the body in a definite order, and stopping thought (stopping what Gurdjieff called “formatory thought” or “mechanical thought”, so as to allow a higher level of thought to operate). According to the theory, by stopping formatory thought while receiving impressions, the impressions can be received more consciously, and so serve as a better quality “food” the alchemical human “food factory.” This also aims to have the effect of allowing a feeling of oneself, rather than negative emotions, to appear. By facilitating consciousness of the sensation of one’s body, freedom from negative emotion and from mechanical thought, we are believed to become more open to higher influences, and hence to a higher state of being.
7

Kostyuchenko, Yuriy V., Yulia Stoyka, Iurii Negoda, and Ivan Kopachevsky. "Decision Making Under Deep Uncertainty With Fuzzy Algorithm in Framework of Multi-Model Approach." In Soft Computing Techniques and Applications in Mechanical Engineering, 1–34. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-3035-0.ch001.

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Task of soft computing for decision support in field of risk management is analyzed in this chapter. Multi-model approach is described. Interrelations between models, remote sensing data and forecasting are described. Method of water quality assessment using satellite observation is described. Method is based on analysis of spectral reflectance of aquifers. Correlations between reflectance and pollutions are quantified. Fuzzy logic based approach for decision support in field of water quality degradation risk is discussed. Decision on water quality is making based on fuzzy algorithm using limited set of uncertain parameters. It is shown that this algorithm allows estimate water quality degradation rate and pollution risks. Using proposed approach, maps of surface water pollution risk from point and diffuse sources are calculated. Conclusions concerned soft computing in risk management are proposed and discussed. It was demonstrated, that basing on spatially distributed measurement data, proposed approach allows to calculate risk parameters with resolution close to observations.
8

Lehnert, Konrad W. "Dynamic and Multimode Electromechanics." In Quantum Optomechanics and Nanomechanics, 307–28. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198828143.003.0008.

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These notes discuss electromechanical devices in the quantum regime, a topic closely related to cavity optomechanics. Both cavity optomechanics and quantum electromechanics have their roots in gravitational-wave detection. As such, most of their applications are associated with ultrasensitive sensing. In contrast, these notes deal with an emerging application of quantum electromechanics: signal processing. Such applications are a natural consequence of shrinking the mechanical elements from the metre-scale resonators used in gravitational wave detectors to the micron scale, where quantum effects are more evident. Indeed, MEMS are a crucial technology for classical information processing and modern wireless communication. The advent of quantum information processing, particularly with superconducting circuits, means that there is now a need for analogue signal processing functions operating at microwave frequencies and in the quantum regime. Electromechanical devices have now entered this regime as they can store, amplify, squeeze, entangle, temporally shape, and frequency convert microwave signals.
9

Alonso Moro, Jorge, Carlos Quiterio Gómez Muñoz, and Fausto Pedro García Márquez. "Predictive Analysis of Robotic Manipulators Through Inertial Sensors and Pattern Recognition." In Handbook of Research on Big Data Clustering and Machine Learning, 334–44. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-0106-1.ch015.

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Industrial robotics is constantly evolving, with installation forecast of about 2 million new robots in 2020. The predictive maintenance focused on industrial robots is beginning to be applied more, but its possibilities have not yet been fully exploited. The present study focuses on the applications offered by inertial sensors in the field of industrial robotics, specifically the possibility of measuring the “real” rotation angle of a robotic arm and comparing it with its own system of measure. The study will focus on the measurement of the backlash existing in the gearbox of the axis of a robot. Data received from the sensor will be analysed using the wavelet transform, and the mechanical state of the system could be determined. The introduction of this sensing system is safe, dynamic, and non-destructive, and it allows one to perform the measurement remotely, in the own installation of the robot and in working conditions. These features allow one to use the device in different predictive functions.
10

Venkata Satya Siva Srikanth, Vadali. "Unique Surface Modifications on Diamond Thin Films." In Engineering Applications of Diamond. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98186.

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Diamond thin films are touted to be excellent in surface-sensitive sensing, electro-mechanical systems, and electrochemical applications. However, these applications often entail patterned active surfaces and subtle chemical surface modifications. But due to diamond’s intrinsic hardness and chemical inertness, surface patterning (using micro-machining and ion etching) and chemical surface modifications, respectively, are very difficult. In the case of surface patterning, it is even more challenging to obtain patterns during synthesis. In this chapter, the direct patterning of sub-wavelength features on diamond thin film surface using a femtosecond laser, rapid thermal annealing as a means to prepare the diamond thin film surface as an efficient direct charge transfer SERS substrate (in metal/insulator/semiconductor (MIS) configuration), and implantation of 14N+ ions into the surface and sub-surface regions for enhancing the electrical conductivity of diamond thin film to a certain depth (in MIS configuration) will be discussed encompassing the processing strategies and different post-processing characteristics.

Тези доповідей конференцій з теми "Mechanical mode sensing":

1

Seshia, Ashwin A. "Mode-localized sensing in micro- and nano-mechanical resonator arrays." In 2016 IEEE SENSORS. IEEE, 2016. http://dx.doi.org/10.1109/icsens.2016.7808399.

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2

Fazzio, R. Shane, Walter Dauksher, Atul Goel, and Tina Lamers. "Analysis of Micromachined Piezoelectric Transducers Operating in a Flexural Mode." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41460.

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Micromachined acoustic transducers have recently emerged in multiple application domains. Bulk acoustic resonators, for example, are extensively used as filters in the cellular handset industry. As another example, silicon capacitive microphones are rapidly replacing electret-condenser devices in consumer electronics platforms. Piezoelectric materials are commonly used in acoustic sensing applications. Combining micromaching with piezoelectric thin-films opens up possibilities of multiple new applications, in addition to the miniaturization of existing sensors. Applications may be as diverse as nondestructive test, acoustic imaging, vibration sensing, acceleration/force sensing, or electroacoustics. This paper presents analysis and measured behavior of micromachined devices constructed as a molybdenum, aluminum nitride, molybdenum trilayer and operating in a flexural mode. A theoretical analysis is derived using thin-plate bending theory. Finite-element simulation results of plate dynamics are examined, and sensitivities and linearity of manufactured devices are shown.
3

Gurjar, Miheer, and Nader Jalili. "An Adaptive Self-Sensing Strategy for Piezoelectrically-Actuated Microcantilevers Used in Ultra-Small Mass Sensing Applications." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15196.

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This paper presents a mathematical model of a self-sensing microcantilever beam for mass sensing applications. Equations of motion are derived for a microcantilever beam with a tip mass and a piezoelectric patch actuator deposited on the cantilever surface. In the self-sensing mode, the same piezoelectric patch is used for actuation and sensing. Selfinduced voltage signals, which are extracted using a capacitive bridge mechanism, reveal frequency information of the vibrating beam, which in turn, reveals the particle mass. Equations of motion are obtained using the extended Hamilton's principle by considering the microcantilever as a distributed- parameters system. Two methods to estimate the unknown tip mass are presented. The first one is based on an inverse solution to the characteristic equation problem, while the second method uses a constraint-based optimization approach to estimate the tip mass. To improve the self-sensing performance, the need for adaptive estimation of the piezoelectric capacitance is stressed and an online estimation mechanism is presented. Simulations are presented to demonstrate the ability of the model to detect tip mass up to 0.1 femtogram (1 femtogram = 10-15 gm). Further simulation results demonstrate the working of constraint optimization method and adaptive self-sensing mechanism.
4

Hu, S. D., H. Li, and H. S. Tzou. "Sensing Signal and Energy Generation Analysis on a Flexoelectric Beam." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-87215.

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Flexoelectricity is known as an electromechanical gradient coupling effect. The direct flexoelectric effect that can convert mechanical strain gradient into electric polarization (or electric field) plays an important role in charge generation in the situation when piezoelectricity is absent. This study focuses on the application of the direct flexoelectric effect based on a flexoelectric cantilever beam to investigate its effectiveness of sensing signal and energy generation. The dielectric cantilever beam is deposited with electrodes both on top and bottom surfaces to generate an electric voltage. The sensing mechanism of flexo-piezo-electric effect is analyzed and the expression of sensing signal is derived. Results show that the output sensing signal is only contributed by the flexoelectric effect while the piezoelectric effect is eliminated due to the symmetric bending strains through the beam thickness. The spatial distribution of sensing signal when the fully covered electrode is uniformly segmented to 10 patches is evaluated as an illustration, and the flexoelectric sensitivity of about 0.15V/mm for the first mode and 4V/mm for the fourth mode is achieved. The optimal sensing position is dependent of the electrode size and the vibration mode and in general, it locates where the difference between the slopes at two ends of the electrode patch reaches maximum. Based on the flexoelectric voltage, the energy generation power is also conducted when the flexoelectric cantilever beam is treated as distributed energy harvesters. As a result, the maximal power of RMS is about 1.5×10−8W/mm for the first mode and increases to about 0.6mW/mm for the fourth mode. It provides an alternative way to harvest electric energy from the ambient vibration without using piezoelectricity.
5

Li, Fang, Lifeng Qin, and Qing-Ming Wang. "Theoretical and Experimental Studies of Love Mode Surface Acoustic Wave Sensors for Cellular Sensing." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39279.

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Cell-based biosensors have the capacity to respond to a wide range of analytes in a physiologically relevant manner. By employing living cells as sensors, bioanalytes can be screened without requiring apriori knowledge of the analyte’s chemistry. The ability to operate and screen for unknown analytes provides benefits in numerous applications, including pharmacology, cell biology, toxicology, and environmental monitoring. Recent studies have demonstrated that acoustic wave devices are capable of quantitatively probing the behaviors of cells attaching to sensor surface. Among various types of acoustic devices, Love mode sensor has many advantages in liquid environment. However, up to now, the use of Love mode devices as cell-based sensors is limited, including theoretical and experimental studies. In this study, we developed a theoretical model for cell-based Love mode sensors. The devices were designed, fabricated and utilized for cell adhesion monitoring.
6

Yu, Lingyu, Victor Giurgiutiu, Jingjiang Wang, and Yong-June Shin. "Corrosion Detection/Quantification on Thin-Wall Structures Using Multi-Mode Sensing Combined With Statistical and Time-Frequency Analysis." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11886.

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In this paper, we present a multiple mode sensing methodology to detect active corrosion in aluminum structure utilizing the broadband piezoelectric wafer active sensors. This method uses ultrasonic Lamb wave complemented with the electromechanical impedance measurement to detect, quantify, and localize the corrosion progression in plate-like structures. The ultimate objective of this research is to develop in-situ multimode sensing system for the monitoring and prediction of critical aerospace structures that can be used during in-service period, recording and monitoring the changes over time. The test experiments were conducted on an aluminum plate installed with a five sensor network using 7-mm piezoelectric wafer active sensors. The corrosion was emulated as material loss of an area of 50mm 38mm on the other surface of the plate. Detection of corrosion and its growth was first conducted using the Lamb wave method in pitch-catch mode. The corroded area resulted in a thickness loss on the Lamb wave propagation and caused the amplitude and phase changes in the structural responses. The experimental data was first evaluated by the statistics-based damage indicator using root mean square deviation. Though the damage indicator is able to detect the presence of the corrosion and identify the corrosion location quantitatively, it failed in giving the right indication of corrosion development. A more corrosion signal processing based method, the cross time-frequency analysis, was proposed and used to analyze the phase characteristics of the data set. This cross time-frequency analysis was found more reliable and precise for detecting the corrosion progression compared with the damage indicator method.
7

Pfusterschmied, Georg, Martin Kucera, Christoph Weinmann, Michael Schneider, Achim Bittner, Jose Luis Sanchez-Rojas, and Ulrich Schmid. "Two-step procedure for multi-mode MEMS resonator-based sensing of fluid properties." In 2017 IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2017. http://dx.doi.org/10.1109/memsys.2017.7863583.

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8

Ardebili, Mahmoud K., Kerim T. Ikikardaslar, and Feridun Delale. "Strain and Damage Sensing of CNT-Epoxy Composite via Electrical Conductivity." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39972.

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Self-sensing via piezoresistivity of multiwall carbon nanotube-epoxy resin composite was studied in order to assess its feasibility in strain and damage detection. Self-sensing is an economical and durable component of Structural Health Monitoring of manufactured composite, in which the material is employed as sensor. Objective of the study centered on strain and damage sensing and particularly focused on how applied tension and /or inflicted damage affected electrical conductivity. The MWCNT-epoxy composite was manufactured with non-treated multiwall carbon-nanotubes. They were dispersed in the epoxy employing ultrasonic dispersion and mechanical mixing, prior to addition of curing agent. The samples were rectangular specimen of dimensions 150 mm × 25 mm × 5 mm. Surface electrodes were created with sliver paint, to which copper wire leads were wrapped and affixed with more silver paint or carbon based electrically conductive glue. Kelvin in-line resistivity measurement technique was adopted to assess and monitor composite resistivity. The technique minimizes contact resistance between electrodes and the composite, which could be order of magnitude larger than the material resistance. For strain sensing, the specimen was subjected to increasing tensile strain until failure. In damage sensing, the specimens received different depth surface cuts across their width. During the tensile strain testing the specimens failed at a typical strain of about 4%. The corresponding change in resistance was in range of 2–3%. In damage sensing mode, changes of up to 40% in resistance were recorded for 75% thickness deep damage. For lower depth damages, the change in resistivity were about 4%–10%. The data obtained so far indicate that with proper technique, self-sensing of CNT-epoxy resin composites could be a viable method for monitoring applied strain and structural integrity.
9

Yu, Lingyu, Victor Giurgiutiu, Yuh Chao, and Patrick Pollock. "In-Situ Multi-Mode Sensing With Embedded Piezoelectric Wafer Active Sensors for Critical Pipeline Health Monitoring." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43234.

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Pipelines are important infrastructures in petroleum and gas industries which are vital to the national economy. They are typically subjected to corrosion inside of the pipe and there is an urgent need for the development of a cost-effective, non-excavating, in-service, permanent critical pipeline damage detection and prediction system. In this paper, we proposed an in-situ multiple mode pipeline monitoring system by utilizing permanently installed piezoelectric wafer active sensors (PWAS). As an active sensing device, PWAS can be bonded to the structure or inserted into a composite structure, operated in propagating wave mode or electromechanical impedance mode. The small size and low cost (about ∼$10 each) make it a potential and unique technology for in-situ application. Additionally, PWAS transducers can operate at a temperature as high as 260°C which is sufficient for most critical pipeline systems used in gas/petroleum industry. This system can be used during in-service period, recording and monitoring the changes, such as cracks, impedance, wall thickness, etc., of the pipelines over time. Having the real-time data available, maintenance strategies based on these data can then be developed to ensure a safe and less expensive operation of the pipeline systems. The paper will first give an intensive literature review of current pipeline corrosion detection. Then, the basic principles of applying PWAS to in-situ SHM using in-plane propagation waves and impedance measurement for damage detection are studied and developed. Next, experiments were conducted to verify the corrosion detection and thickness measurement ability of PWAS sensor network in a laboratory setting and in water pipe with flowing fluid inside as well. In addition, the potential of PWAS application for high temperature pipeline thickness monitoring was also investigated.
10

Parnas, Richard S., and Dara L. Woerdeman. "Mode Coupling Theory for Evanescent Wave Optical Fiber Sensors." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0628.

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Abstract Optical fiber based sensors have potential in the composites processing industry as well as many other industries, but cost and robustness often mitigate the advantages of optical fiber sensors. The least expensive type of optical fiber sensor is a length of fiber either embedded in the part or in distal contact with the part surface. In the case of embedded evanescent mode sensors, important issues hinge on interpreting the evanescent signal obtained during processing or in service inspection. An optical model based on mode coupling theory is presented below to provide a description of the sensing volume around the fiber from which signal is collected during evanescent measurements. The model is developed for a fluorescence sensor but the optical theory could be equally applied for infrared or other types of optical fiber sensors.

Звіти організацій з теми "Mechanical mode sensing":

1

Galili, Naftali, Roger P. Rohrbach, Itzhak Shmulevich, Yoram Fuchs, and Giora Zauberman. Non-Destructive Quality Sensing of High-Value Agricultural Commodities Through Response Analysis. United States Department of Agriculture, October 1994. http://dx.doi.org/10.32747/1994.7570549.bard.

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The objectives of this project were to develop nondestructive methods for detection of internal properties and firmness of fruits and vegetables. One method was based on a soft piezoelectric film transducer developed in the Technion, for analysis of fruit response to low-energy excitation. The second method was a dot-matrix piezoelectric transducer of North Carolina State University, developed for contact-pressure analysis of fruit during impact. Two research teams, one in Israel and the other in North Carolina, coordinated their research effort according to the specific objectives of the project, to develop and apply the two complementary methods for quality control of agricultural commodities. In Israel: An improved firmness testing system was developed and tested with tropical fruits. The new system included an instrumented fruit-bed of three flexible piezoelectric sensors and miniature electromagnetic hammers, which served as fruit support and low-energy excitation device, respectively. Resonant frequencies were detected for determination of firmness index. Two new acoustic parameters were developed for evaluation of fruit firmness and maturity: a dumping-ratio and a centeroid of the frequency response. Experiments were performed with avocado and mango fruits. The internal damping ratio, which may indicate fruit ripeness, increased monotonically with time, while resonant frequencies and firmness indices decreased with time. Fruit samples were tested daily by destructive penetration test. A fairy high correlation was found in tropical fruits between the penetration force and the new acoustic parameters; a lower correlation was found between this parameter and the conventional firmness index. Improved table-top firmness testing units, Firmalon, with data-logging system and on-line data analysis capacity have been built. The new device was used for the full-scale experiments in the next two years, ahead of the original program and BARD timetable. Close cooperation was initiated with local industry for development of both off-line and on-line sorting and quality control of more agricultural commodities. Firmalon units were produced and operated in major packaging houses in Israel, Belgium and Washington State, on mango and avocado, apples, pears, tomatoes, melons and some other fruits, to gain field experience with the new method. The accumulated experimental data from all these activities is still analyzed, to improve firmness sorting criteria and shelf-life predicting curves for the different fruits. The test program in commercial CA storage facilities in Washington State included seven apple varieties: Fuji, Braeburn, Gala, Granny Smith, Jonagold, Red Delicious, Golden Delicious, and D'Anjou pear variety. FI master-curves could be developed for the Braeburn, Gala, Granny Smith and Jonagold apples. These fruits showed a steady ripening process during the test period. Yet, more work should be conducted to reduce scattering of the data and to determine the confidence limits of the method. Nearly constant FI in Red Delicious and the fluctuations of FI in the Fuji apples should be re-examined. Three sets of experiment were performed with Flandria tomatoes. Despite the complex structure of the tomatoes, the acoustic method could be used for firmness evaluation and to follow the ripening evolution with time. Close agreement was achieved between the auction expert evaluation and that of the nondestructive acoustic test, where firmness index of 4.0 and more indicated grade-A tomatoes. More work is performed to refine the sorting algorithm and to develop a general ripening scale for automatic grading of tomatoes for the fresh fruit market. Galia melons were tested in Israel, in simulated export conditions. It was concluded that the Firmalon is capable of detecting the ripening of melons nondestructively, and sorted out the defective fruits from the export shipment. The cooperation with local industry resulted in development of automatic on-line prototype of the acoustic sensor, that may be incorporated with the export quality control system for melons. More interesting is the development of the remote firmness sensing method for sealed CA cool-rooms, where most of the full-year fruit yield in stored for off-season consumption. Hundreds of ripening monitor systems have been installed in major fruit storage facilities, and being evaluated now by the consumers. If successful, the new method may cause a major change in long-term fruit storage technology. More uses of the acoustic test method have been considered, for monitoring fruit maturity and harvest time, testing fruit samples or each individual fruit when entering the storage facilities, packaging house and auction, and in the supermarket. This approach may result in a full line of equipment for nondestructive quality control of fruits and vegetables, from the orchard or the greenhouse, through the entire sorting, grading and storage process, up to the consumer table. The developed technology offers a tool to determine the maturity of the fruits nondestructively by monitoring their acoustic response to mechanical impulse on the tree. A special device was built and preliminary tested in mango fruit. More development is needed to develop a portable, hand operated sensing method for this purpose. In North Carolina: Analysis method based on an Auto-Regressive (AR) model was developed for detecting the first resonance of fruit from their response to mechanical impulse. The algorithm included a routine that detects the first resonant frequency from as many sensors as possible. Experiments on Red Delicious apples were performed and their firmness was determined. The AR method allowed the detection of the first resonance. The method could be fast enough to be utilized in a real time sorting machine. Yet, further study is needed to look for improvement of the search algorithm of the methods. An impact contact-pressure measurement system and Neural Network (NN) identification method were developed to investigate the relationships between surface pressure distributions on selected fruits and their respective internal textural qualities. A piezoelectric dot-matrix pressure transducer was developed for the purpose of acquiring time-sampled pressure profiles during impact. The acquired data was transferred into a personal computer and accurate visualization of animated data were presented. Preliminary test with 10 apples has been performed. Measurement were made by the contact-pressure transducer in two different positions. Complementary measurements were made on the same apples by using the Firmalon and Magness Taylor (MT) testers. Three-layer neural network was designed. 2/3 of the contact-pressure data were used as training input data and corresponding MT data as training target data. The remaining data were used as NN checking data. Six samples randomly chosen from the ten measured samples and their corresponding Firmalon values were used as the NN training and target data, respectively. The remaining four samples' data were input to the NN. The NN results consistent with the Firmness Tester values. So, if more training data would be obtained, the output should be more accurate. In addition, the Firmness Tester values do not consistent with MT firmness tester values. The NN method developed in this study appears to be a useful tool to emulate the MT Firmness test results without destroying the apple samples. To get more accurate estimation of MT firmness a much larger training data set is required. When the larger sensitive area of the pressure sensor being developed in this project becomes available, the entire contact 'shape' will provide additional information and the neural network results would be more accurate. It has been shown that the impact information can be utilized in the determination of internal quality factors of fruit. Until now,
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Engel, Bernard, Yael Edan, James Simon, Hanoch Pasternak, and Shimon Edelman. Neural Networks for Quality Sorting of Agricultural Produce. United States Department of Agriculture, July 1996. http://dx.doi.org/10.32747/1996.7613033.bard.

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The objectives of this project were to develop procedures and models, based on neural networks, for quality sorting of agricultural produce. Two research teams, one in Purdue University and the other in Israel, coordinated their research efforts on different aspects of each objective utilizing both melons and tomatoes as case studies. At Purdue: An expert system was developed to measure variances in human grading. Data were acquired from eight sensors: vision, two firmness sensors (destructive and nondestructive), chlorophyll from fluorescence, color sensor, electronic sniffer for odor detection, refractometer and a scale (mass). Data were analyzed and provided input for five classification models. Chlorophyll from fluorescence was found to give the best estimation for ripeness stage while the combination of machine vision and firmness from impact performed best for quality sorting. A new algorithm was developed to estimate and minimize training size for supervised classification. A new criteria was established to choose a training set such that a recurrent auto-associative memory neural network is stabilized. Moreover, this method provides for rapid and accurate updating of the classifier over growing seasons, production environments and cultivars. Different classification approaches (parametric and non-parametric) for grading were examined. Statistical methods were found to be as accurate as neural networks in grading. Classification models by voting did not enhance the classification significantly. A hybrid model that incorporated heuristic rules and either a numerical classifier or neural network was found to be superior in classification accuracy with half the required processing of solely the numerical classifier or neural network. In Israel: A multi-sensing approach utilizing non-destructive sensors was developed. Shape, color, stem identification, surface defects and bruises were measured using a color image processing system. Flavor parameters (sugar, acidity, volatiles) and ripeness were measured using a near-infrared system and an electronic sniffer. Mechanical properties were measured using three sensors: drop impact, resonance frequency and cyclic deformation. Classification algorithms for quality sorting of fruit based on multi-sensory data were developed and implemented. The algorithms included a dynamic artificial neural network, a back propagation neural network and multiple linear regression. Results indicated that classification based on multiple sensors may be applied in real-time sorting and can improve overall classification. Advanced image processing algorithms were developed for shape determination, bruise and stem identification and general color and color homogeneity. An unsupervised method was developed to extract necessary vision features. The primary advantage of the algorithms developed is their ability to learn to determine the visual quality of almost any fruit or vegetable with no need for specific modification and no a-priori knowledge. Moreover, since there is no assumption as to the type of blemish to be characterized, the algorithm is capable of distinguishing between stems and bruises. This enables sorting of fruit without knowing the fruits' orientation. A new algorithm for on-line clustering of data was developed. The algorithm's adaptability is designed to overcome some of the difficulties encountered when incrementally clustering sparse data and preserves information even with memory constraints. Large quantities of data (many images) of high dimensionality (due to multiple sensors) and new information arriving incrementally (a function of the temporal dynamics of any natural process) can now be processed. Furhermore, since the learning is done on-line, it can be implemented in real-time. The methodology developed was tested to determine external quality of tomatoes based on visual information. An improved model for color sorting which is stable and does not require recalibration for each season was developed for color determination. Excellent classification results were obtained for both color and firmness classification. Results indicted that maturity classification can be obtained using a drop-impact and a vision sensor in order to predict the storability and marketing of harvested fruits. In conclusion: We have been able to define quantitatively the critical parameters in the quality sorting and grading of both fresh market cantaloupes and tomatoes. We have been able to accomplish this using nondestructive measurements and in a manner consistent with expert human grading and in accordance with market acceptance. This research constructed and used large databases of both commodities, for comparative evaluation and optimization of expert system, statistical and/or neural network models. The models developed in this research were successfully tested, and should be applicable to a wide range of other fruits and vegetables. These findings are valuable for the development of on-line grading and sorting of agricultural produce through the incorporation of multiple measurement inputs that rapidly define quality in an automated manner, and in a manner consistent with the human graders and inspectors.

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