Bibliografias temáticas / Small force metrology

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Literatura científica selecionada sobre o tema "Small force metrology"

Autor: Grafiati

Publicado: 1 de março de 2025

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Artigos de revistas sobre o assunto "Small force metrology"

HU, GANG, LE SONG, FENG MENG, WEI ZHANG, ZHIMIN ZHANG, YUE ZHANG e YELONG ZHENG. "RESEARCH AND DEVELOPMENT OF SMALL FORCE STANDARDS AT NIM". International Journal of Modern Physics: Conference Series 24 (janeiro de 2013): 1360020. http://dx.doi.org/10.1142/s2010194513600203.

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With the development and industrialization of micro- and nano- technology, small force measurements are widely applied in many fields such as advanced materials, bio-technology, aerospace and so on. For realizing traceable small forces and founding small force metrology hierarchy in China, NIM has launched a research project on small force metrology in 2011. 2 methods for small force realization at the scale of nano-Newton to micro-Newton are applied: electrical force based method and mass based method. The initial prototype of small force standard, which is based on the electrostatic force realization and adopts a coaxial cylindrical capacitor, has been developed and experimented. 2 kinds of micro force transmission mechanism are applied to the prototype: a parallelogram mechanism with 4 flexure hinges, and a lever-type force measurement system based on an elastic torsion bar. The structure and key units of 2 schemes are described in detail, the experiment results are demonstrated. The system stiffness of torsion bar scheme is smaller than that of flexure hinges scheme. In addition, structure of the initial prototype will be improved, and the environment conditions will be controlled strictly in our further experiments to minimize the creep of our system.

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Cameron, Robert P., Duncan McArthur e Alison M. Yao. "Strong chiral optical force for small chiral molecules based on electric-dipole interactions, inspired by the asymmetrical hydrozoan Velella velella". New Journal of Physics 25, n.º 8 (1 de agosto de 2023): 083006. http://dx.doi.org/10.1088/1367-2630/ace7ee.

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Abstract Drawing inspiration from a remarkable chiral force found in nature, we show that a static electric field combined with an optical lin ⊥ lin polarization standing wave can exert a chiral optical force on a small chiral molecule that is several orders of magnitude stronger than other chiral optical forces proposed to date, being based on leading electric-dipole interactions rather than relying on weak magnetic-dipole and electric-quadrupole interactions. Our chiral optical force applies to most small chiral molecules, including isotopically chiral molecules, and does not require a specific energy-level structure. Potential applications range from chiral molecular matter-wave interferometry for precision metrology and tests of fundamental physics to the resolution of enantiomers for use in chemistry and biology.

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Pratt, Jon R., Douglas T. Smith, David B. Newell, John A. Kramar e Eric Whitenton. "Progress toward Système International d'Unités traceable force metrology for nanomechanics". Journal of Materials Research 19, n.º 1 (janeiro de 2004): 366–79. http://dx.doi.org/10.1557/jmr.2004.19.1.366.

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Recent experiments with the National Institute of Standards and Technology (NIST) Electrostatic Force Balance (EFB) have achieved agreement between an electrostatic force and a gravitational force of 10−5 N to within a few hundred pN/μN. This result suggests that a force derived from measurements of length, capacitance, and voltage provides a viable small force standard consistent with the Système International d’Unités. In this paper, we have measured the force sensitivity of a piezoresistive microcantilever by directly probing the NIST EFB. These measurements were linear and repeatable at a relative standard uncertainty of 0.8%. We then used the calibrated cantilever as a secondary force standard to transfer the unit of force to an optical lever–based sensor mounted in an atomic force microscope. This experiment was perhaps the first ever force calibration of an atomic force microscope to preserve an unbroken traceability chain to appropriate national standards. We estimate the relative standard uncertainty of the force sensitivity at 5%, but caution that a simple model of the contact mechanics suggests errors may arise due to friction.

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NIKOLAEV, M. YU, E. V. NIKOLAEVA e A. K. NIKITIN. "PROCESS MODELING AND METROLOGY IN ELECTRICAL IMPULSE SYSTEMS". Actual Issues Of Energy 4, n.º 1 (2022): 070–74. http://dx.doi.org/10.25206/2686-6935-2022-4-1-70-74.

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Electromagnetic force pulses are forces of mutual repulsion between the inductor and the anchor. Under their action, the anchor is shifted towards the cleaned surface of the affected object and elastic vibrations are transmitted to it. In electro-pulse interaction systems, the duration of the energy accumulation process, and then its release in extremely small time intervals, allows to obtain the maximum possible values of mechanical impulse action on the surface of the affected object. The maximum operating voltage on a capacitive energy storage device can reach 5 kV or higher. Electro-pulse interaction systems are shock-type devices. Compared with other devices of similar purpose (vibrators, electromagnetic or pneumatic shock mechanisms), they have no competition in terms of cleaning efficiency.

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Pinto, Fabrizio. "Nanomechanical sensing of gravitational wave-induced Casimir force perturbations". International Journal of Modern Physics D 23, n.º 12 (outubro de 2014): 1442001. http://dx.doi.org/10.1142/s0218271814420012.

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It is shown by means of the optical medium analogy that the static Casimir force between two conducting plates is modulated by gravitational waves. The magnitude of the resulting force changes within the range of already existing small force metrology. It is suggested to enhance the effects on a Casimir force oscillator by mechanical parametric amplification driven by periodic illumination of interacting semiconducting boundaries. This represents a novel opportunity for the ground-based laboratory detection of gravitational waves on the nanoscale.

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Dai, Gao Liang, F. Pohlenz, H. U. Danzebrink e L. Koenders. "Dimensional Measurements for Micro- and Nanotechnology". Key Engineering Materials 381-382 (junho de 2008): 7–10. http://dx.doi.org/10.4028/www.scientific.net/kem.381-382.7.

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Metrology plays an important role in the development and commercialisation of micro and nanotechnology. For calibrating versatile micro- and nanoscale standards, a dimensional metrology instrument coupled with multi sensor heads including atomic force microscope (AFM), tactile stylus, laser focus sensor and assembled cantilever probes (ACPs) has been developed. Two kinds of ACPs are highlighted in the paper. One is fabricated by gluing a vertical AFM cantilever to a horizontal AFM cantilever using micro assembling techniques. It is applicable for direct and non-destructive measurements of sidewall surfaces. The other is an ACP ball probe designed for true 3D measurements of micro structures. It is realised by gluing a tungsten wire with a probing sphere ball, 40 ... 120 µm in diameter, to a horizontal AFM cantilever. The ACP ball probe has advantages such as small probing forces (<1µN) and high probing sensitivity. Some typical calibrations on micro and nano structures such as step height, grating and sphere calotte artefact are introduced.

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Nikolaev, M. Yu, E. V. Nikolaeva, N. Yu Khokriakov, A. A. Kovalevsky e К. I. Stolyarchuk. "SIMULATION OF ELECTRIC PULSES, THEIR PRACTICAL APPLICATION AND ISSUES OF METROLOGY". ACTUAL ISSUES OF ENERGY 5, n.º 1 (2023): 67–75. http://dx.doi.org/10.25206/2686-6935-2023-5-1-67-75.

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electromagnetic force pulses are forces of mutual repulsion between the anchor and the inductor. Under their action, the anchor is shifted towards the cleaned surface of the affected object and elastic vibrations are transmitted to it. In electro-pulse interaction systems, the duration of the energy accumulation process, and then its release in extremely small time intervals, allows to obtain the maximum possible values of mechanical impulse action on the surface of the affected object. The maximum operating voltage on a capacitive energy storage is capable of reaching 5 kV and higher. Electro-pulse interaction systems are shock-type devices. Compared with other devices of similar purpose (vibrators, electromagnetic or pneumatic shock mechanisms), they have no competition in terms of cleaning efficiency.

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Shaw, Gordon A. "Current state of the art in small mass and force metrology within the International System of Units". Measurement Science and Technology 29, n.º 7 (22 de maio de 2018): 072001. http://dx.doi.org/10.1088/1361-6501/aaac51.

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Mooney, C. B., J. T. Thornton e P. E. Russell. "Effects of deformation of electron-beam-grown microtips on measurements taken with the Atomic-Force Microscope". Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 1072–73. http://dx.doi.org/10.1017/s0424820100173091.

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When imaging with an Atomic-Force Microscope (AFM), the image resolution is a complex function of the relative tip and sample geometries. When imaging or measuring high aspect ratio features, sharp and slender tips offer the possibility of probing down into extremely small topographical features. The most commonly used contact mode AFM tips are thin film cantilevers of Si3N4 with an integrated pyramidal structure used as the tip. It has been shown that microtips, which are fabricated by electron beam induced growth of carbonaceous material on the apex of the pyramid, can reduce the artifacts associated with integrated pyramidal AFM tips. A SEM micrograph of a microtip grown on the apex of an integrated pyramid is shown in Figure 1. Use of grown microtips in metrology demands an understanding of the dynamics of microtip deformation while scanning.

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ZHANG, ZHIMIN, YUE ZHANG, TAO LI e HONGLEI JI. "THE DESIGN OF 1 N•M TORQUE STANDARD MACHINE AT NIM". International Journal of Modern Physics: Conference Series 24 (janeiro de 2013): 1360024. http://dx.doi.org/10.1142/s2010194513600240.

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A 1 N•m torque standard machine has been designed and developed at National Institute of Metrology (NIM) since 2011. The torque standard machine adopts the moment arm-deadweight type, the air bearing with low friction is adopted to support the moment-arm at the fulcrum, the invar with the low expansion coefficient is used as the material of the moment-arm, the weight suspension part and weight loading system are specially designed to ensure the applied force by small weights accurately and reliably. This paper introduces the mechanical structures of the machine, the electrical control system is described. 1 N•m torque standard machine is capable of realizing the torque from 1 mN•m to 1 N•m both in clockwise and anti-clockwise directions.

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Mais fontes

Teses / dissertações sobre o assunto "Small force metrology"

Hernandez-Sabio, Sylvain. "Contribution à la métrologie des faibles forces : traçabilité des mesures dynamiques par inversion ensembliste". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCD058.

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Cette thèse est une contribution à la métrologie des faibles forces qui s'inscrit dans la continuité des activités de recherche menées au département AS2M de l'institut FEMTO-ST. Ce manuscrit présente la conception et la mise en œuvre expérimentale d'un accéléromètre pendulaire triaxial qui mesure les composantes non filtrées du régime sismique, puisque ces dernières sont susceptibles de perturber le fonctionnement d'une balance de micro-nanoforce électromagnétique actuellement en développement. Une méthodologie alternative de calcul est également proposée dans ce manuscrit afin d'estimer spécifiquement la valeur et l'incertitude associée à une ou plusieurs grandeurs d'intérêt inconnues, par l'intermédiaire d'un système dynamique SISO dont le comportement est incertain et perturbé. Cette approche repose sur la représentation exacte de ce système grâce à une entrée correctrice virtuelle qui contient les grandeurs d'intérêt. Cette entrée est estimée puis mise en forme afin de déterminer l'incertitude associée à ces grandeurs d'intérêt, en utilisant les outils de l'analyse par intervalles. La méthodologie proposée est validée à partir de simulations de l'accéléromètre en modes actif et passif, puis illustrée sur le dispositif expérimental. Une étude en simulation du fonctionnement couplé de la future balance de micro-nanoforce électromagnétique avec l'accéléromètre triaxial est également réalisée. L'approche proposée est mise en œuvre lors d'un essai simulé visant à caractériser la raideur mécanique d'un levier élastique
This PhD thesis is a contribution to small force metrology, in line with the research activities carried out in the AS2M department of the FEMTO-ST institute. This manuscript presents the design and experimental implementation of a triaxial pendulous accelerometer, which measures the unfiltered seismic activity, since the latter is likely to interfere with the operation of an electromagnetic micro-nanoforce balance currently under development. An alternative methodology is also proposed in this manuscript to specifically estimate the value and uncertainty associated with one or more unknown quantities of interest, using a dynamical SISO system whose behavior is uncertain and disturbed. This approach is based on the exact representation of this system by means of a virtual corrective input containing the quantities of interest. This input is estimated and then shaped to determine the uncertainty associated with these quantities of interest, using the tools of interval analysis. The proposed methodology is validated on the basis of simulated accelerometer responses in active and passive modes, then illustrated on the experimental setup. A simulation study of the coupled operation of the future electromagnetic micro-nanoforce balance with the triaxial accelerometer is also carried out. The proposed approach is implemented in a simulated test aiming at characterizing the mechanical stiffness of an elastic cantilever

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Capítulos de livros sobre o assunto "Small force metrology"

Hussain, Danish, Saif Ullah Awan, Masood Ur Rehman, Uzair Khaleeq uz Zaman e Xie Hui. "Atomic force microscopy based micro and nano sidewall imaging". In Nanoscience, 202–34. Royal Society of Chemistry, 2024. http://dx.doi.org/10.1039/bk9781837674138-00202.

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In the semiconductor industry, micro and nano sidewall structures imaging has high importance for nanomechanical characterization, critical dimension (CD) metrology and fabrication process optimization. Various tools and techniques are used for this purpose e.g. scatterometry, CD-scanning electron microscope, small angle X-ray scattering and atomic force microscope (AFM). Due to its important traits such as high spatial resolution and non-destructive nature, AFM has emerged as an important sidewall structures imaging tool. In this chapter, we will cover AFM-based imaging of micro and nano sidewalls. Conventional AFM has limitations in imaging sidewalls due to the top-down scanning approach. Over the years, several AFM methods have been developed to access the sidewall which includes imaging with shaped AFM probes, tilt-scanning, dual-probe AFM, orthogonal scanning and specialized AFM methods. In addition, the recently developed orthogonal probing sidewall imaging technique has ushered its importance in nanomaterial characterization on the sidewalls while obtaining force–distance curves on the micro and nano sidewalls.

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Trabalhos de conferências sobre o assunto "Small force metrology"

Arroyo, M. Pilar, José Antonio Bea, Nieves Andrés, Rosario Osta e Manuel Doblaré. "Force plate for measuring small animal forces by digital speckle pattern interferometry". In Optical Metrology, editado por Wolfgang Osten, Christophe Gorecki e Erik L. Novak. SPIE, 2007. http://dx.doi.org/10.1117/12.732044.

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Shaw, Gordon A., Paul Williams, Julian Stirling, Felipe Guzman-Cervantes e John Lehman. "Using small mass and force metrology for laser power measurement". In 2016 Conference on Precision Electromagnetic Measurements (CPEM 2016). IEEE, 2016. http://dx.doi.org/10.1109/cpem.2016.7540726.

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Brand, U., Z. Li, R. Popadic, K. Hiller, S. Hahn, T. Frank, G. Hamdana et al. "Small Force Metrology for AFM, Stylus Instruments, CMM and Nanoindenter". In 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018). IEEE, 2018. http://dx.doi.org/10.1109/cpem.2018.8500987.

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Veronese, Matteo, Alex Caon, Riccardo Giubilato, Francesco Branz e Alessandro Francesconi. "Development of a Multi-Axial Force Sensor for Small Satellite Docking". In 2024 11th International Workshop on Metrology for AeroSpace (MetroAeroSpace). IEEE, 2024. http://dx.doi.org/10.1109/metroaerospace61015.2024.10591564.

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Jarvis, Charlie, Emily Webster, Stuart Davidson e Ian Robinson. "A µKibble balance for direct realisation of small-scale masses and forces". In 19th International Congress of Metrology (CIM2019), editado por Sandrine Gazal. Les Ulis, France: EDP Sciences, 2019. http://dx.doi.org/10.1051/metrology/201914002.

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Kibble balance experiments have allowed the kilogram to be redefined in terms of the Planck constant. Now that the redefinition is in place, the Kibble balance will allow SI traceable mass (or force) to be realised at any value and at any location. A feasibility study for a novel, scalable electrostatic ‘µKibble balance’, based on the National Physical Laboratory (NPL) next-generation Kibble balance system is presented and its expected performance calculated. A µKibble will allow in-situ, dynamic, small-scale (< g) mass measurements without the current precision limitation caused by subdivision of the kilogram. The measurements will be traceable through electrical calibration rather than transferable mass standards. The instrument will have a wide range of applications in both industry and research.

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LEFORT, Romain, Arnaud DECATOIRE, Malek ABDI, Patrick LACOUTURE e Raymond BUISSON. "Development of a new “6-axis” force connected sensor." In 19th International Congress of Metrology (CIM2019), editado por Sandrine Gazal. Les Ulis, France: EDP Sciences, 2019. http://dx.doi.org/10.1051/metrology/201919005.

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This new sensor project has been initiated mainly in order to take measurements in the field of biomechanics during motions of human bodies. For that, it’s necessary to detect the efforts at the contacts with these human bodies in real situation, such as during working, walking, running, biking and so on. Up to now, most of 6 components force sensors which are used, for instance are sensors with each component measuring device as perfectly as possible decoupled from each other’s. This leads to expansive or very expansive sophisticated sensors. The present sensor is a stand-alone wireless, small sized 6-axis force sensor with a powerful and precise conditioning and acquisition system. The sensitive cell is a raw Stewart mechanical structure (strain-gages based) with, conversely to usual multicomponent sensors, force and moment components not decoupled at all, but optimally coupled. Owing to the powerful numerical capabilities of the sensor, the 6 effective components of a given mechanical action are instantaneously computed. Thanks to that, even for small quantity production, the sensor cost price is significantly reduced. This reduction is bigger for larger quantity productions like for: robotics, machine tools, hoisting machines… Added to the sensor design, the project include also a theoretical mechanical research in order to find an accurate calibration method, as easy as possible to be performed. This results in calibration tests needing only a standard traction-compression test machine running with mechanical effects decoupling tools dimensioned so that the calibration relative uncertainty is kept below 1‰. With that, only 6 elementary loading tests have to be applied to the sensor. The whole sequence of calibration is done automatically, completely governed by a powerful calculation and acquisition software. All the raw tests results (strain in µm/m) are automatically collected, converted and analyzed. At the end of the numerical treatment of each set of measurements, all the calibration data attesting the traceability to the International System of units (SI) of the sensor, including : raw calibration results, sensitivities coefficients matrix needed for later data reduction and conversion in solicitation components (force and moment), sensor performances characteristic curves (non-linearity, hysteresis error curve, zero shift error, etc.), calibrations uncertainties, are stored in the computer memory. The calibration matrix is then uploaded on the sensor. So, the measurement results (values of solicitations components) are directly expressed in mechanical units traceable to SI. This sensor is able to perform high data rate wireless streaming with time-synchronization protocol or low data rate transmissions compatible with IOT connectivity. The following paper describes and comments most important engineering job sequences and calibration results. It’s also an example of future connected sensors structures able to gather, not only the staff needed to give accurate high levels measurement results, but also all the key pieces of information’s relative to the measurement traceability proof and quality management, all of them being instantaneously available on the net (IOT). This research and development job got the funding of FEDER-FSE-2014-2020 Nouvelle-Aquitaine program and of CRITT-Sport et Loisirs.

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Khelifa, Naceur-Eddine. "Miniaturized Nd-YAG laser as photoelastic transducer for small forces sensing". In 17th International Congress of Metrology, editado por Bernard Larquier. Les Ulis, France: EDP Sciences, 2015. http://dx.doi.org/10.1051/metrology/20150004002.

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Juethner, Konrad, Ted Rose, J. S. Kumar, Jianming Cao, Gregory M. Savela, Chris J. Zuck e Parag H. Mathuria. "Finite Element Analysis of Bent Rotors". In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-79752.

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Abstract The rotating components of a gas turbine engine are typically designed around a perfectly straight centerline. In spite of advanced manufacturing technology and the conviction of the human eye, straightness is virtually impossible to achieve during manufacturing and assembly. High-tech metrology can quantify ever so slight centerline deviations along the unconstrained rotor assembly which are called bends. Related phenomena are rotor bow and thermal bow, the latter of which is normally due to asymmetric cooling after engine shutdown. Yet, bent and bowed rotors differ from one another in that bends are permanent deviations from the centerline of the unconstrained rotor, whereas rotor bow is temporary, typically elastic, and observed in the mounted, and therefore constrained, rotor assembly. Greater complexity is introduced with the realization that a bent rotor can additionally be subject to rotor bow. The presence of bends leads to force and moment distributions along the rotating structure that can have significant dynamic implications for even very small bends. In opposition to unbalance loads, which increase with rotor speed, the rotating excitation of a bent rotor remains constant. The equations of motion (EOM) of a bent rotor are very well defined in the literature by Refs [1, 2]. However, the analysis is usually confined to simplified cases where said centerline deviations at the bearing supports are zero. For realistic rotor applications, this is not the case and an additional static analysis is required to obtain the proper dynamic load distribution along the rotor. In this paper, the finite element method (FEM) is used to analyze bent rotors within an MSC NASTRAN v2021 work-flow that can address rotor models of any complexity. The proposed approach can also account for static, compliant, and greatly featured support structures that communicate with the rotor model via its common, and potentially misaligned, bearing supports. Angular and lateral offsets are explored in three different scenarios of two rotor configurations: Scenarios 1 and 2 introduce a simply bent rotor, along which synchronous force and moment distributions are computed (due to its intrinsic deviations) to subsequently excite the bent rotor dynamically. While Scenario 1 requires an initial static analysis with enforced displacements to accomplish this task, the equivalent dynamic excitation of Scenario 2 can be computed directly due to perfect bearing alignment. In Scenario 3, the complexity of the rotor bend is increased to four angular kinks and four lateral offsets to suggest the deployment of this method in combination with hightech metrology equipment that can produce a large number of such measurements via automated probing or scanning technologies. In a final step, the bent rotor is augmented with unbalances and compared to its nominal counterpart to deliver the motivation for this method and its value to the turbomachinery community. All results of Scenarios 1, 2, and 3 are verified against an experimentally validated transfer matrix method (TMM).

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Juluri, Naresh, Elie Dib, Sherif el-Gebaly e Philip Cooper. "Reliability Based Deep Water Spool Piece Design". In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10010.

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Long spools are often required to absorb the end expansion of deep water high pressure and high temperature flowlines. These spools typically have significant metrology and fabrication tolerances. Metrology and spool fabrication tolerances lead to misalignments at the connector hub face. Residual loads then arise from spool deformation due to the installation forces that are required to match-up the connector faces. It is a current industry practice to design the spools for multiple independent tolerances at extreme limits in all directions. Previous project experience shows that the Algebraic Sum (AS) combination of multiple independent tolerances at extreme limits may result in large spools where the probability of occurrence of these tolerances at extreme limits is quite low. The use of less conservative SRSS (square root of sum of squares) combination has been suggested in this paper as an alternative to the Algebraic Sum combination. Due to the large number of misalignment components, the probability of exceeding the loads in the spool and at the connector obtained by the SRSS method is small and is within the applicable failure probabilities defined in DNV-OS-F101. The SRSS method is demonstrated in this paper by using a Monte Carlo simulation. Five different spools have been analysed to demonstrate the suitability of using SRSS misalignments when the spools are designed to DNV-OS-F101. The spools considered include 10″, 16″ and 20″ outside diameter spools to represent different sizes at different loading combinations. Maximum bending moments in the spool and maximum moments at the connector have been considered to check the SRSS feasibility. The results indicate that it is acceptable to use SRSS misalignments as an alternative to AS misalignments. Considering SRSS misalignments in preference to AS leads to reduced spool size and reduced loadings on connectors.

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Neighborgall, Campbell, Timothy Mast, Andrew Peterson, Mehdi Ahmadian e Carvel Holton. "Development of Laser/LED-Based Instrument for Optical Detection of Railroad Top-of-Rail (ToR) Friction Modifiers and Lubricity Conditions". In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1285.

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This study provides the results of research for obtaining track lubricity conditions through using laser/LED-based, optical sensors while onboard a push-cart. The resulting sensors are intended to be able to identify the lubricity condition of a rail network while moving onboard either a track metrology car or a Hy-rail vehicle. U.S. railroads invest a large sum of money and resources applying friction modifying material and flange lubricants to their rails to reduce rolling resistance in curves in an effort to reduce curving forces, reduce wheel and rail wear, and improve fuel efficiency. There exists, however, no effective ways of measuring the amount, adequacy, or even presence of top of rail (ToR) friction modifiers over continuous, extended distances of track except through quasi-empirical visual inspections that can be subject to a high amount of errors due to the very small layer thicknesses of ToR material (commonly, a few microns). This effort intends to bridge this gap by evaluating the application of laser/LED-based instruments in detecting the presence of ToR friction modifiers and flange lubricants on the rail. Specifically, the reflective and scattering properties of a laser beam directed against the rail surface are used to provide a qualitative “gloss”-based assessment of the presence of ToR friction modifiers. Additionally, a UV fluorescence sensor (LED source) is used to detect the presence of flange grease which has migrated to the top of rail by taking advantage of the grease’s fluorescence properties. The results of both laboratory and field testing of a prototype system with embedded laser and LED fluorescence sensors and supporting peripheral sensors are presented. The details of the instruments and their working principle are explained. The conditions for laboratory testing and field testing on revenue service tracks are detailed. The test results indicate that the laser/LED system is capable of successfully detecting the presence of ToR friction modifier and flange grease contamination on the rail.

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