Relevant bibliographies by topics / Forced Response Analysis

Academic literature on the topic 'Forced Response Analysis'

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Published: 10 March 2023

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Journal articles on the topic "Forced Response Analysis"

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Nikolic, M., E. P. Petrov, and D. J. Ewins. "Coriolis Forces in Forced Response Analysis of Mistuned Bladed Disks." Journal of Turbomachinery 129, no. 4 (August 15, 2006): 730–39. http://dx.doi.org/10.1115/1.2720866.

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The problem of estimating the mutual interaction of the effects of Coriolis forces and of blade mistuning on the vibration characteristics of bladed disks is addressed in this paper. The influence of different degrees of mistuning on forced response and amplification factors are studied in the presence of Coriolis forces and then compared to their non-Coriolis counterparts using a computationally inexpensive, yet representative, model of a bladed disk. The primary objective of the study reported in this paper is to establish whether current mistuned bladed disk analyses should incorporate Coriolis effects in order to represent accurately all the significant factors that affect the forced response levels.
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Alligné, S., P. C. O. Silva, A. Béguin, B. Kawkabani, P. Allenbach, C. Nicolet, and F. Avellan. "Forced response analysis of hydroelectric systems." IOP Conference Series: Earth and Environmental Science 22, no. 4 (March 1, 2014): 042001. http://dx.doi.org/10.1088/1755-1315/22/4/042001.

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Berthillier, M., C. Dupont, R. Mondal, and J. J. Barrau. "Blades Forced Response Analysis With Friction Dampers." Journal of Vibration and Acoustics 120, no. 2 (April 1, 1998): 468–74. http://dx.doi.org/10.1115/1.2893853.

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A multiharmonic frequency domain analysis combined with a Craig-Bampton component mode synthesis is presented to compute the dry friction damped forced response of blades. The accuracy of the analysis is established, for a cantilever beam with a dry friction damper attached, by comparison with experimental results and time domain analysis. The method has then been applied to a model fan blade damped by a blade to ground damper.
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Chiang, Hsiao-Wei D., and R. E. Kielb. "An Analysis System for Blade Forced Response." Journal of Turbomachinery 115, no. 4 (October 1, 1993): 762–70. http://dx.doi.org/10.1115/1.2929314.

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A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes and/or pressure disturbances from adjacent blade rows. The standard method for dealing with this problem is to avoid resonant conditions using a Campbell diagram. Unfortunately, it is impossible to avoid all resonant conditions. Therefore, judgments based on past experience are used to determine the acceptability of the blade design. A new analysis system has been developed to predict blade forced response. The system provides a design tool, over and above the standard Campbell diagram approach, for predicting potential forced response problems. The incoming excitation sources are modeled using a semi-empirical rotor wake/vortex model for wake excitation, measured data for inlet distortion, and a quasi-three-dimensional Euler code for pressure disturbances. Using these aerodynamic stimuli, and the blade’s natural frequencies and mode shapes from a finite element model, the unsteady aerodynamic modal forces and the aerodynamic damping are calculated. A modal response solution is then performed. This system has been applied to current engine designs. A recent investigation involved fan blade response due to inlet distortion. An aero mechanical test had been run with two different distortion screens. The resulting distortion entering the fan was measured. With this as input data, the predicted response agreed almost exactly with the measured response. In another application, the response of the LPT blades of a counterrotating supersonic turbine was determined. In this case the blades were excited by both a wake and a shock wave. The shock response was predicted to be three times larger than that of the wake. Thus, the system identified a new forcing function mechanism for supersonic turbines. This paper provides a basic description of the system, which includes: (1) models for the wake excitation, inlet distortion, and pressure disturbance; (2) a kernel function solution technique for unsteady aerodynamics; and (3) a modal aeroelastic solution using strip theory. Also, results of the two applications are presented.
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HSUEH, W. J. "FORCED RESPONSE ANALYSIS FOR MULTI-LAYERED STRUCTURES." Journal of Sound and Vibration 227, no. 1 (October 1999): 222–29. http://dx.doi.org/10.1006/jsvi.1999.2362.

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david Logan, J. "Forced response of a linear hyperbolic system." Applicable Analysis 33, no. 3-4 (January 1989): 255–66. http://dx.doi.org/10.1080/00036818908839877.

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Saito, Akira, and Tatsuya Suzuki. "Forced response vibration analysis of induction motor stators induced by electromagnetic forces." IFAC-PapersOnLine 55, no. 27 (2022): 155–59. http://dx.doi.org/10.1016/j.ifacol.2022.10.504.

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Chiang, Hsiao-Wei D., and Sanford Fleeter. "Analysis of forced response of detuned blade rows." Journal de Physique III 2, no. 4 (April 1992): 527–44. http://dx.doi.org/10.1051/jp3:1992146.

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Yildirim, Kenan, and Sertan Alkan. "Dynamic Response Analysis of a Forced Fractional Viscoelastic Beam ∗." Journal of Mathematics 2021 (December 15, 2021): 1–10. http://dx.doi.org/10.1155/2021/3920937.

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In this paper, dynamic response analysis of a forced fractional viscoelastic beam under moving external load is studied. The beauty of this study is that the effect of values of fractional order, the effect of internal damping, and the effect of intensity value of the moving force load on the dynamic response of the beam are analyzed. Constitutive equations for fractional order viscoelastic beam are constructed in the manner of Euler–Bernoulli beam theory. Solution of the fractional beam system is obtained by using Bernoulli collocation method. Obtained results are presented in the tables and graphical forms for two different beam systems, which are polybutadiene beam and butyl B252 beam.
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Qi, Fu Qiang. "Dynamic Response Analysis of Bridge Pier Subject to Earthquake and Ice Loads." Advanced Materials Research 250-253 (May 2011): 2211–15. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2211.

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In order to discuss the effect of earthquake and dynamic ice loads to a bridge pier, this paper considered the effect of added mass of dynamic water, and it deduced the dynamic equilibrium equations for a bridge pier subject to earthquake and dynamic ice loads on the basis of nonlinear Morision equation. Using numerical analysis method, it discussed the dynamic response of a bridge pier subject to different types of earthquake loads, forced ice loads, and both earthquake and forced ice loads. Through comparing the pier responses in different work conditions, it discovered that the dynamic responses of the bridge pier subject to forced dynamic ice loads rise and fall severely at the time of ice buckling broken periodic change. The coupling effects of forced dynamic ice loads and earthquake especially near-fault earthquake enhance the dynamic response of bridge pier significantly.
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Dissertations / Theses on the topic "Forced Response Analysis"

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Sladojevic, Ivan. "Forced response analysis of aero-elastically coupled mistuned bladed discs." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438210.

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Hutton, Timothy M. "Innovative Forced Response Analysis Method Applied to a Transonic Compressor." Wright State University / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=wright1074801945.

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Dolasa, Anaita Rustom. "Computer-Aided Design Software for the Undamped Two-Dimensional Static and Dynamic Analysis of Beams and Rotors." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/32283.

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The objective of this research work was to develop a design tool to analyze and design undamped beam and rotor systems in two dimensions. Systems modeled in two dimensions, such as beams with different moments of inertia, could produce varying responses in the each direction of motion. A coupling between the vertical and horizontal motions also exists in rotor systems mounted of fluid film bearings. The computer program called 2DBEAM has been developed to model and provide analyses of such systems in two dimensions. The tool has been based on an existing design package, BEAM9, which in its present state provides the response of beams and rotors in one plane of motion. The 2DBEAM program has the capability of performing the static response, free vibration, forced dynamic response, and frequency response analyses of a system. The Transfer Matrix Method has been used in the development of the software and an explanation of the method is included in this thesis. Mathematical problems and solutions encountered while developing 2DBEAM are also documented in this study. The code has been tested against analytical and published solutions for the types of analysis mentioned above and on coupled and uncoupled system models.
Master of Science
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Griffin, Timothy R. "Computer-Aided Design Software for Torsional Analysis." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36548.

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The goal of this research has been the development of an effective design tool for torsional analysis. In the hopes of achieving this goal the computer program, Torsion 1, has been created. This torsional transfer matrix program provides the user with the ability to easily model multi-rotor systems using a simple user-interface. The program is capable of modeling such components or system characteristics as continuously distributed mass, viscous and structural damping, vibration absorbers, and gear meshes with gear tooth flexibility. The analysis capabilities of the program include forcedresponse and free-vibration analyses. The forced-response analysis module is capable of determining a system’s response to a static or harmonic torsional load. The free-vibration analysis module allows is capable of determining the eigenvalues and eigenvectors for damped and undamped systems. This thesis includes an explanation of the multi-rotor transfer matrix technique employed in Torsion 1. The derivation of transfer matrices for visco-elastic vibration absorbers, pendulum absorbers, flexible gear meshes, and planetary gear trains are included in this work. Finally, the validity of the program results is verified with a set of benchmark examples.
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Romanov, Artyom. "Investigation and development of low-fidelity analytical models for forced response, flutter and distortion propagation analysis." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24425.

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The study describes a methodology for the analysis and design of turbomachinery components at low-fidelity level. This methodology is part of a broad, object-oriented environment developed at the Rolls-Royce VUTC. The approach described in this thesis is applicable to any axial turbomachinery configuration, however, main emphasis is made on compressors. The purpose of the research is to provide the opportunity to perform forced response, flutter and other unsteady analysis without the need for the expensive CFD runs. This is particularly demanded in the early stages of the aero-engine design process or in any other cases when the detailed information of the engine is not yet available, however, a broad unsteady parametric analysis based on the existing information is needed. The model uses a linearized form of the mass, momentum and energy budgets to relate small changes in the state of the gas at several positions in the machine to known disturbances at inlet or outlet, or to known changes in the geometry. The chosen approach allows usage of an arbitrary gas model without the assumption of constant gas properties. It also provides a straightforward way to obtain a steady-state solution in a minimal amount of iterations and to evaluate the exact values of the characteristic slopes. The unsteady solution methodology represents an extended and improved Semi-Actuator Disc model. The major improvements are the real geometry application, ability to handle rotating bladerows, loss models implementation and the cascade impedance model. As the solver is linearized, the harmonic perturbations are assumed to have small amplitude compared to the steady-state data and relatively long wavelength, compared to the blade measurements. Thus contributions of several perturbation sources may be superimposed within the model. The model has a block-wise structure, where every block represents a blade or an empty duct. Non-reflecting boundary conditions are applied to the blocks boundary interfaces together with a thought-through method for the angular frequency scattering. This allows assembling a multi-bladerow domain with both rotating and stationary bladerows for the unsteady analysis. A great deal of effort has been made to connect the system to a modern and general representation of the engine geometry. This data is then used to set up the domain geometry with minimal assumptions, thus considering the changes in areas, radii and the slope of the annulus. The complex blade profile information is accessible at any moment during the computation, thus allowing using a chosen set of loss and deviation models. The model uses the same geometry database as used for the CFD and FE analysis, however, any geometry data may be overridden on demand. The model has been validated on a variety of data, from the previous publications, for forced response and flutter and from alternative solvers for distorted casings. The agreement between the calculated results and the reference data is very satisfactory, with nearly exact match for a series of idealized cases. The improvements introduced in this approach, such as cascade impedance model and the loss and deviation model package extend and complete several statements made in previous publications regarding the effect of total pressure loss and presence of the passage end reflections. The model is also validated against more complex reference cases, such as 3D CFD simulation of the LP turbine blade flutter, providing a good estimation of the damping curve slope in the low-ND region. Having a tip clearance loss model, the non-uniform casing simulations have been setup for evaluation of the relationship between the unsteady mass flow and pressure ratio perturbations. A thorough literature survey is made on the previous publications of the similar subject. The survey reviews a series of the modular systems for the axial turbomachinery analysis and then continues with the investigation of semi-empirical closures for the total pressure loss and outlet flow deviation modelling. The latter two play an essential role in this research as their implementation provides more realistic results, comparable to the heavy CFD runs. Greater part of the survey is devoted to the previous publications on various approaches for 1D and 2D unsteady turbomachinery modelling. The research completes with a thorough discussion of the features implemented and the results achieved, concluding with several future work proposals for the eventual further extension of the model as well as its applicability as a keystone for possible construction of a higher-fidelity solver. The primary programming object-oriented environment chosen for the model implementation is C++ with some parts written in FORTRAN.
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Gagne, Anton. "Effects of Asymmetry and Other Non-Standard Excitations on Structural Dynamic Forced Response Analysis of Turbomachinery Flow-Path Components." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-154623.

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A recent paper explored a potential deficiency in the single frequency harmonic response structural dynamic analysis approach typically used to assess a resonant condition in turbomachinery flow path components. This deficiency is prevalent in supersonic flow conditions when non-adjacent stages are present. The previous investigation demonstrated other excitation sources present in complex or supersonic flows could be missed using the typical analysis approach, in some cases leading to large under-prediction of structural response when compared with a baseline transient analysis. This paper presents the results of a follow on study, in which the inclusion of these effects in dynamic analyses is investigated. A representative rotor was created and analyzed for forced response characteristics when individual and combined unsteady content was present. A simple shell and beam 2D model was used to study the forced response behavior using transient and harmonic analyses. The results showed a significant contribution from non-integer forcing as well as from certain integer order forcing. A 3D model was also created for future analysis but did not display the sideband characteristics similar to flow seen in the previous investigation.
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Henry, Emily Brooke. "Stochastic Modeling of Geometric Mistuning and Application to Fleet Response Prediction." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1421095761.

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Albannai, Humaid Ali Mohammad. "Combating the trafficking of women in the United Arab Emirates : a critical analysis of the United Arab Emirates legal response in the context of international law." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17141.

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The United Arab Emirates (UAE) is a key destination and transit country for human trafficking. Human trafficking is a complex international criminal enterprise that supplies humans for many different forms of forced labour and commercial sexual exploitation. It has devastating effects on its victims. Theories suggest that human trafficking is strongly linked to migration, which would explain why it has become an urgent issue for the UAE, since its massive influx of migrants seeking a better life and economic circumstances, are habitually lured to the UAE and subjected to exploitation by traffickers. It is a situation that in recent years has tarnished the UAE's reputation to the international community and its wealthy investors. It is for all of these reasons that this thesis is concerned with human trafficking in the UAE, with a special focus on the trafficking of women, as well as the legal mechanisms and initiatives created to combat this scourge. At the heart of this investigation is Federal Law No. 51 which marked a pivotal moment for the UAE, as it was a law specifically designed to address trafficking on its territory. However, as with laws drafted by the international community, there exist difficulties with how trafficking should be construed, and with how traffickers and trafficked victims should be treated in order to effectively eliminate this crime. Ultimately, the research highlights the importance and benefits of a victim-centred human rights based approach, as opposed to the pervasive crime control one, which includes ensuring that victims are genuinely protected and fully rehabilitated to re-enter society. In addition, the research provides crucial insights from Islamic law and principles that raise significant implications for understanding how the trafficking in women should be conceptualised and dealt with in modern-day Muslim societies such as the UAE.
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Garafolo, Nicholas Gordon. "AN EXPERIMENTAL INVESTIGATION OF MULTIPLE MODE EXCITATION OF AN INTEGRALLY BLADED DISK." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1164047919.

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Timorian, Safiullah. "Investigation for the analysis of the vibrations of quasi-periodic structures." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCD002.

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Dans cette thèse, la définition et les effets de la quasi-périodicité dans la structure périodique sont étudiés. Plus important encore, l'analyse de la présence de faibles irrégularités dans les structures périodiques et de son impact significatif sur les réponses vibroacoustiques des systèmes élastiques est abordée. Dans la littérature, il a déjà été montré qu'un panneau sandwich optimisé par rapport aux performances vibroacoustiques et doté de propriétés aléatoires ajoutées du noyau pouvait présenter des caractéristiques de bande d'arrêt dans certaines gammes de fréquences. Par conséquent, une cible supplémentaire peut consister à encadrer la propriété susmentionnée sous la méthode des éléments finis vagues (WFEM) afin d’aboutir à certaines directives de conception. Dans ce travail, (1) sont présentées des études numériques de l'analyse vibrationnelle de faisceaux finis, périodiques et quasi-périodiques 1D. Le contenu traite des modèles d'éléments finis de faisceaux axés sur l'analyse spectrale et les réponses forcées amorties. La quasi-périodicité est définie en appelant la séquence de Fibonacci pour construire les variations affectées (géométrie et matériau) le long de la plage du modèle d'éléments finis dans une direction. De même, la même plage est utilisée comme une super unité cellulaire avec WFEM pour analyser les systèmes périodiques infinis. (2) La méthode de variation avec un algorithme développé est également considérée pour rechercher le déséquilibre géométrique d'impédance le plus efficace des cellules unitaires pour le contrôle des vibrations. (3) Des études numériques et des mesures expérimentales sur des réseaux bidimensionnels périodiques et quasi périodiques sont ainsi effectuées. Les validations expérimentales sont effectuées en comparant le réseau quasi-périodique simulé en utilisant la modélisation WFEM avec un prototype fabriqué par usinage laser. Les principaux résultats montrent que, en considérant à la fois les ondes élastiques longitudinales et de flexion dans les faisceaux 1D, les gammes de fréquences correspondant aux bandes interdites sont étudiées. Dans les structures 2D, les caractéristiques des ondes du réseau quasi-périodique introduisent la possibilité de concevoir des bandes d'arrêt de fréquence plus larges dans les gammes de basses fréquences. Elles présentent certains éléments novateurs et pourraient être prises en compte pour la conception de filtres structurels et le contrôle des propriétés des ondes élastiques. Les résultats obtenus dans cette thèse montrent que le faisceau avec les caractéristiques de Fibonacci et les panneaux avec les caractéristiques de Thue-Morse peuvent améliorer les performances en termes d’atténuation sans pénalité de poids, ce qui peut être un avantage pour les méta-matériaux
In this thesis, the definition and effects of quasi-periodicity in periodic structure are investigated. More importantly, the presence of irregularity in periodic structures and its significant impact in vibroacoustic responses of elastic systems are analyzed. In the extant literature, it has already shown that a sandwich panel, optimized for vibroacoustic performance with added random properties of the core, can exhibit stop band characteristics in some frequency ranges. Therefore, an additional target can exist in framing the abovementioned property under the Wave Finite Element Method (WFEM) for resulting in some design guideline. In this paper, (1) the numerical stud- ies of the vibrational analysis of 1D finite, periodic, and quasi-periodic beams are presented. The paper's content deals with the finite element models of beams focusing on spectral analysis and the damped forced responses. The quasi-periodicity is defined by invoking the Fibonacci sequence for building the assigned variations (geometry and material) along the span of the finite element model in one direction. Similarly, the same span is used as a super unit cell with WFEM for analyzing the infinite periodic systems. (2) The method of variation with a developed algorithm is also considered to find the most efficient geometrical impedance mismatch behavior of unit cells for vibration control. (3) Numerical studies and experimental measurements on 2D periodic and quasi-periodic lattices are thus performed. Experimental validations are performed by comparing the quasi-periodic lattice simulated by using WFEM modelling, with a prototype manufactured by laser machin- ing. Based on the major findings, and considering both longitudinal and flexural elastic waves in 1D beams, the frequency ranges corresponding to band gaps are investigated. In the 2D structures, the wave characteristics in the quasi-periodic lattice introduce the possibility of designing wider fre- quency stop bands in low frequency ranges, and presents some elements of novelty; moreover, they can be considered for designing structural filters and controlling the properties of elastic waves. The results obtained in this study show that the beam with Fibonacci characteristics and panels with Thue- Morse characteristics can improve performances in terms of attenuation level without weight penalty, which can be an asset for metamaterials
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Books on the topic "Forced Response Analysis"

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Karl, Owen A., United States. National Aeronautics and Space Administration., and U.S. Army Research Laboratory., eds. Forced response testing of an axi-centrifugal turboshaft engine. [Washington, DC]: National Aeronautics and Space Administration, U.S. Army Research Laboratory, 1997.

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R, Srivastava, Mehmed O, and NASA Glenn Research Center, eds. Flutter and forced response analyses of cascades using a two-dimensional linearized Euler solver. Cleveland, Ohio: National Aeronautics and Space Administration, Glenn Research Center, 1999.

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R, Srivastava, and United States. National Aeronautics and Space Administration., eds. User's guide for MSAP2D: A program for unsteady aerodynamic and aeroelastic (flutter and forced response) analysis of multistage compressors and turbines : under grant NAG3-1137. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Meeting, Cornwallis Group. The Cornwallis Group V: Analysis for crisis response and societal reconstruction. Clementsport, N.S: Canadian Peacekeeping Press, 2000.

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S, Howe Michael, and Langley Research Center, eds. Reciprocity-based experimental determination of dynamic forces and moments: A feasibility study. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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S, Howe Michael, and Langley Research Center, eds. Reciprocity-based experimental determination of dynamic forces and moments: A feasibility study. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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S, Howe Michael, and Langley Research Center, eds. Reciprocity-based experimental determination of dynamic forces and moments: A feasibility study. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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V, Leyendecker Edgar, and Geological Survey (U.S.), eds. USGS Spectral response maps and their relationship with seismic design forces in building codes. [Denver, CO]: U.S. Geological Survey, 1995.

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Moret, Joëlle. The path of Somali refugees into exile: A comparative analysis of secondary movements and policy responses. Neuchâtel, Switzerland: Swiss Forum for Migration and Population Studies, 2006.

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Plümmer, Franziska. Rethinking Authority in China’s Border Regime. NL Amsterdam: Amsterdam University Press, 2022. http://dx.doi.org/10.5117/9789463726351.

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In the 21st century, governments around the globe are faced with the question on how to tackle new migratory mobilities. Governments increasingly become aware of irregular immigration and are forced to re-negotiate the dilemma of open but secure borders. Rethinking Authority in China’s Border Regime: Regulating the Irregular investigates the Chinese government’s response to this phenomenon. Hence, this book presents a comprehensive analysis of the Chinese border regime. It explores the regulatory framework of border mobility in China by analysing laws, institutions, and discourses as part of an ethnographic border regime analysis. It argues that the Chinese state deliberately creates ‘zones of exception’ along its border. In these zones, local governments function as ‘scalar managers’ that establish cross-border relations to facilitate cross-border mobility and create local migration systems that build on their own notion of legality by issuing locally valid border documents. The book presents an empirically rich story of how border politics are implemented and theoretically contributes to debates on territoriality and sovereignty as well as to the question of how authority is exerted through border management. Empirically, the analysis builds on two case studies at the Sino-Myanmar and Sino-North Korean borders to illustrate how local practices are embedded in multiscalar mobility regulation including regional organizations such as the Greater Mekong Subregion and the Greater Tumen Initiative.
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Book chapters on the topic "Forced Response Analysis"

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Giannini, O. "Forced Response of 2-Dof Gyroscopic Systems with Stable Eigenvalues." In Topics in Modal Analysis & Testing, Volume 9, 15–23. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74700-2_3.

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Perumal, Shanmugam, Raghunathan Swaminathan, and Mike Christensen. "Forced Vibration Harmonic Response Analysis of Semi-mobile Crusher Station." In Lecture Notes on Multidisciplinary Industrial Engineering, 157–69. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8468-4_14.

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Hong, Ling, Jun Jiang, and Jian-Qiao Sun. "Response Analysis of a Forced Duffing Oscillator with Fuzzy Uncertainty." In Advances in Intelligent Systems and Computing, 3–13. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-07494-8_1.

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Holmes, D. G., and H. A. Chuang. "2D Linearized Harmonic Euler Flow Analysis for Flutter and Forced Response." In Unsteady Aerodynamics, Aeroacoustics, and Aeroelasticity of Turbomachines and Propellers, 213–30. New York, NY: Springer New York, 1993. http://dx.doi.org/10.1007/978-1-4613-9341-2_11.

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Sandul, Amy L., and Veda B. Moore. "Harm Reduction: Tipping the Balance Toward Treatment and Recovery." In Public Health Ethics Analysis, 141–52. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92080-7_10.

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AbstractOpioid use has risen dramatically over the past 40 years. In response, federal programs and policies aimed at decreasing supply of prescription opioids have stabilized excessive prescribing. Unintended consequences of limiting the quantity of prescription opioids in the population has resulted in increased use of illicit drugs and opened a pathway of transition from misuse of pills to injection of heroin and use of potent formulations of cheap, synthetic opioids such as fentanyl. Harm reduction interventions function at the community level to provide health benefits and avoidance of harm to persons engaging in illicit and injection drug use. The Consolidated Appropriations Act of 2016 gives states, local, tribal, and territorial health departments the opportunity to use federal money to support a comprehensive set of harm reduction services. Critics of harm reduction strategies argue that formalizing and legalizing certain activities creates the perception that communities and local authorities are sanctioning or encouraging illicit/illegal drug use. Syringe services programs that provide clean needles and syringes so people who inject drugs are not forced to share or reuse injection equipment, are often at the heart of such controversy. This story addresses tensions that exist in communities grappling with harm reduction approaches to opioid and injection drug use.
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Kizilay, H. Sefa, and Ender Cigeroglu. "On the Solution of Nonlinear Algebraic Equations Following Periodic Forced Response Analysis of Nonlinear Structures Using Different Nonlinear Solvers." In Nonlinear Structures & Systems, Volume 1, 121–27. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-47626-7_20.

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Chowdhury, Indrajit, and Shambhu P. Dasgupta. "Dynamic Response of Bunkers and Circular Silos Under Earthquake Force." In Earthquake Analysis and Design of Industrial Structures and Infra-structures, 919–72. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-90832-8_13.

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Breunung, Thomas, and George Haller. "Time-varying Spectral Submanifolds: Analytic Calculation of Backbone Curves and Forced Response." In Nonlinear Dynamics, Volume 1, 141–42. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74280-9_12.

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Oh, Seungin, Yongbeom Cho, Kang-Heon Lee, and Jin-Gyun Kim. "Real-Time Estimation of Unmeasured Vibro-acoustic Responses Using Inverse Force Identification Technique." In Topics in Modal Analysis & Parameter Identification, Volume 8, 77–80. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-05445-7_9.

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Reill, Peter H. "Analogy, Comparison, and Active Living Forces: Late Enlightenment Responses to the Skeptical Critique of Causal Analysis." In The Skeptical Tradition Around 1800, 203–11. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-017-3465-3_16.

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Conference papers on the topic "Forced Response Analysis"

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Vasanthakumar, Parthasarathy, and Paul-Benjamin Ebel. "Forced Response Analysis of a Transonic Fan." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69867.

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The forced response of turbomachinery blades is a primary source of high cycle fatigue (HCF) failure. This paper deals with the computational prediction of blade forced response of a transonic fan stage that consists of a highly loaded rotor along with a tandem stator. In the case of a transonic fan, the forced response of the rotor due to the downstream stator assumes significance because of the transonic flow field. The objective of the present work is to determine the forced response of the rotor induced as a result of the unsteady flow field due to the downstream stator vanes. Three dimensional, Navier-Stokes flow solver TRACE is used to numerically analyse the forced response of the fan. A total of 11 resonant crossings as identified in the Campbell diagram are examined and the corresponding modeshapes are obtained from finite element modal analysis. The interaction between fluid and structure is dealt with in a loosely coupled manner based on the assumption of linear aerodynamic damping. The aerodynamic forcing is obtained by a nonlinear unsteady Navier-Stokes computation and the aerodynamic damping is obtained by a time-linearized Navier-Stokes computation. The forced response solution is obtained by the energy method allowing calculations to be performed directly in physical space. Using the modal forcing and damping, the forced response amplitude can be directly computed at the resonance crossings. For forced response solution, the equilibrium amplitude is reached when the work done on the blade by the external forcing function is equal to the work done by the system damping (aerodynamic and structural) force. A comprehensive analysis of unsteady aerodynamic forces on the rotor blade surface as a result of forced response of a highly loaded transonic fan is carried out. In addition, the correspondence between the location of high stress zones identified from the finite element analysis and the regions of high modal force identified from the CFD analysis is also discussed.
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Nikolic, M., E. P. Petrov, and D. J. Ewins. "Coriolis Forces in Forced Response Analysis of Mistuned Bladed Discs." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90315.

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The problem of estimating the mutual interaction of the effects of Coriolis forces and of blade mistuning on the vibration characteristics of bladed discs is addressed in this paper. The influence of different degrees of mistuning on forced response and amplification factors are studied in the presence of Coriolis forces and then compared to their non-Coriolis counterparts using a computationally inexpensive, yet representative, model of a bladed disc. The primary objective of the study reported in this paper is to establish whether current mistuned bladed disc analyses should incorporate Coriolis effects in order to represent accurately all the significant factors that affect the forced response levels.
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Zucca, Stefano, Sergio Filippi, Fabio Droetti, and Muzio M. Gola. "Forced Response of Interlocked Vane Segments: Numerical Predictions and Experimental Results." In ASME 8th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2006. http://dx.doi.org/10.1115/esda2006-95551.

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Resonant vibrations affect fatigue life of vane segments. Friction damping is employed to reduce vibration amplitude. When vane segments are assembled, they are twisted so that lower platforms are in contact. The sum of displacements of the two ends of the lower platform after twisting is defined ‘interlocking’. Different ‘interlocking’ values correspond to different values of normal contact force. When interlocked vanes vibrate under external force excitation, energy is dissipated by friction forces at lower platform contacts providing damping to the system. The aim of this paper is the experimental validation of a numerical code for forced response calculation of interlocked vane segments. Since friction forces depend on relative displacements of bodies in contact, the system is nonlinear. System force response is computed by means of Harmonic Balance Method (HBM). Contact model implemented in the code is characterised by tangential and normal stiffness to take into account local compliance of the contact area. Gross slip occurs when the instantaneous ratio of tangential force to normal force is equal to the friction coefficient. Also effect of microslip is taken in account. The experimental set-up used to validate the code is made of a vane segment fixed at the outer radius to an aluminium frame and in contact with two supports at the inner radius. Comparison between the numerical predictions and experimental results is performed for different values of interlocking (i.e. force normal to the contact).
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Chiang, Hsiao-Wei D., and Robert E. Kielb. "An Analysis System for Blade Forced Response." In ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/92-gt-172.

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A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes, and/or pressure disturbances from adjacent blade rows. The standard method for dealing with this problem is to avoid resonant conditions using a Campbell diagram. Unfortunately, it is impossible to avoid all resonant conditions. Therefore, judgements based on past experience are used to determine the acceptability of a blade design. A new analysis system has been developed to predict blade forced response. The system provides a design tool, over and above the standard Campbell diagram approach, for predicting potential forced response problems. The incoming excitation sources are modeled using a semi-empirical rotor wake/vortex model for wake excitation, measured data for inlet distortion, and a quasi-3D Euler code for pressure disturbances. Using these aerodynamic stimuli, and the blade’s natural frequencies and mode shapes from a finite element model, the unsteady aerodynamic modal forces and the aerodynamic damping are calculated. A modal response solution is then performed. This system has been applied to current engine designs. A recent investigation involved fan blade response due to inlet distortion. An aeromechanical test had been run with two different distortion screens. The resulting distortion entering the fan was measured. With this as input data, the predicted response agreed almost exactly with the measured response. In another application, the response of the LPT blades of a counter-rotating supersonic turbine was determined. In this case the blades were excited by both a wake and a shock wave. The shock response was predicted to be three times larger than that of the wake. Thus, the system identified a new forcing function mechanism for supersonic turbines. This paper provides a basic description of the system, which includes: 1) models for the wake excitation, inlet distortion, and pressure disturbance; 2) a kernel function solution technique for unsteady aerodynamics; and 3) a modal aeroelastic solution using strip theory. Also, results of the two applications are presented.
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Ekici, Kivanc, Robert Kielb, and Kenneth Hall. "Forced Response Analysis of Aerodynamically Asymmetric Cascades." In 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2010. http://dx.doi.org/10.2514/6.2010-6535.

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Siewert, Christian, and Heinrich Stu¨er. "Forced Response Analysis of Mistuned Turbine Bladings." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-23782.

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It is well-known that the vibrational behavior of a mistuned bladed disk differs strongly from that of a tuned bladed disk. A large number of publications dealing with the dynamics of a mis-tuned bladed disk is available in the literature. Nearly all published mechanical models for a mistuned bladed disk consider the mistuning in terms of a perturbation of the mass and/or the stiffness matrix or in terms of a perturbation of the tuned system natural frequencies. Therefore, the possible effect of a damping mistuning is neglected in these models. In this paper, a model of a mistuned bladed disk with a combined damping and natural frequency mistuning is presented. This model is based on the well-known Fundamental Model of Mistuning with a novel extension to include the damping mistuning in a straight-forward way.
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Rastogi, Naveen. "Forced Frequency Response Analysis of Multimaterial Systems." In SAE 2005 Noise and Vibration Conference and Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2005. http://dx.doi.org/10.4271/2005-01-2374.

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Beirow, Bernd, Arnold Kühhorn, Thomas Giersch, and Jens Nipkau. "Forced Response Analysis of a Mistuned Compressor Blisk." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94142.

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The forced response of an E3E-type HPC-blisk front rotor is analyzed with regard to varying mistuning and the consideration of the fluid-structure interaction (FSI). For that purpose, a reduced order model is used in which the disk remains unchanged and mechanical properties of the blades namely stiffness and damping are adjusted to measured as well as intentional blade frequency mistuning distributions. The aerodynamic influence coefficient technique is employed to model the aeroelastics. Depending on the blade mode, the exciting engine order and aerodynamic influences it is sought for the worst mistuning distributions with respect to the maximum blade displacement based on optimization analyses. Genetic algorithms using blade alone frequencies as design variables are applied. The validity of the Whitehead-limit is assessed in this context. In particular, the question is addressed if and how far aeroelastic effects, mainly caused by aerodynamic damping, combined with mistuning can even cause a reduction of the forced response compared to the ideally tuned blisk. It is shown that the strong dependence of the aerodynamic damping on the inter-blade phase angle is the main driver for a possible response attenuation considering the fundamental as well as a higher blade mode. Furthermore, the differences to the blisk vibration response without a consideration of the flow and an increase of the disk’s stiffness are discussed. Closing, the influence of pure damping mistuning is analyzed again using optimization.
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Geihe, Benedict, Christian Frey, and Graham Ashcroft. "Efficient Forced Response Analysis for Asymmetric Vane Spacing." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-82983.

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Abstract In the context of forced response analysis, we present a computationally efficient method to capture the effect of inflow distortions caused by intentional variation of cyclic vane spacing. Applying such configurations is a typical mitigation strategy when unforeseen critical blade vibrations occur due to synchronous excitation by wakes of an upstream row. Altering the circumferential distance in a section-wise pattern effectively distributes the fluctuations among several engine order frequencies, thereby reducing their amplitudes. The rotationally asymmetric configurations initially call for multi-passage simulations. We show that the circumferential spectrum can be well approximated using single passage results only, without significant additional costs. Our approach is based on an analytically computed Fourier transform of a synthesis functional. For validation, we consider a turbine test case with transonic and subsonic operating points. We determine the reduction in amplitude of dominant inflow modes for an explicitly constructed instance with asymmetric vane spacing and compare our analytical predictions to full-wheel simulations. Furthermore we assess the impact on aerodynamic excitation of downstream rotor blades using both a frequency and a time domain solver.
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Siewert, Christian, Lars Panning, Jo¨rg Wallaschek, and Christoph Richter. "Multiharmonic Forced Response Analysis of a Turbine Blading Coupled by Nonlinear Contact Forces." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59201.

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The rotor blades of a low pressure (LP) steam turbine stage are subjected to high static and dynamic loads during operation. The static loads are mainly due to the centrifugal force and thermal strains, whereas the dynamic loads are caused by fluctuating gas forces resulting in forced vibrations of the blades. The forced vibrations can lead to high cycle fatigue (HCF) failures causing substantial damage and high maintenance effort. Thus, one of the main tasks in the design of LP steam turbine blading is the vibration amplitude reduction in order to avoid high dynamic stresses that could damage the blading. The vibration amplitudes of the blades in a LP steam turbine stage can be reduced significantly to a reasonable amount if adjacent blades are coupled by shroud contacts that reinforce the blading, see Fig. 1. Furthermore, in the case of blade vibrations, relative displacements between neighboring blades occur in the contacts and friction forces are generated that provide additional damping to the structure due to the energy dissipation caused by micro- and macroslip effects. Therefore, the coupling of the blades increases the overall mechanical damping. A three-dimensional structural dynamics model including an appropriate spatial contact model is necessary to predict the contact forces generated by the shroud contacts and to describe the vibrational behavior of the blading with sufficient accuracy. To compute the nonlinear forced vibrations of the coupled blading, the nonlinear equations of motion are solved in the frequency domain owing to the high computational efficiency of this approach. The transformation of the nonlinear equations of motion into the frequency domain can be carried out by representing the steady-state displacement in terms of its harmonic components. After that transformation, the nonlinear forced response is computed as a function of the excitation frequency in the frequency domain.
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Reports on the topic "Forced Response Analysis"

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Paul W. Reimus and Marc J. Haga. Analysis of tracer responses in the BULLION Forced-Gradient Experiment at Pahute Mesa, Nevada. Office of Scientific and Technical Information (OSTI), October 1999. http://dx.doi.org/10.2172/752365.

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Chang, Arturo, Thomas Ferguson, Jacob Rothschild, and Benjamin I. Page. Ambivalence About International Trade in Open- and Closed-ended Survey Responses. Institute for New Economic Thinking Working Paper Series, September 2021. http://dx.doi.org/10.36687/inetwp162.

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Spontaneous, open-ended survey responses can sometimes better reveal what is actually on people’s minds than small sets of forced-choice, closed questions. Our analysis of closed questions and trade-related open-ended responses to 2016 ANES “likes” and “dislikes” prompts indicate that Americans held considerably more complex, more ambivalent, and – in many cases – more negative views of international trade than has been apparent in studies that focus only on closed-ended responses. This paper suggests that contrast between open- and closed-question data may help explain why the effectiveness of Donald Trump’s appeals to trade resentments surprised many observers.
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Gunay, Selim, Fan Hu, Khalid Mosalam, Arpit Nema, Jose Restrepo, Adam Zsarnoczay, and Jack Baker. Blind Prediction of Shaking Table Tests of a New Bridge Bent Design. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, November 2020. http://dx.doi.org/10.55461/svks9397.

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Considering the importance of the transportation network and bridge structures, the associated seismic design philosophy is shifting from the basic collapse prevention objective to maintaining functionality on the community scale in the aftermath of moderate to strong earthquakes (i.e., resiliency). In addition to performance, the associated construction philosophy is also being modernized, with the utilization of accelerated bridge construction (ABC) techniques to reduce impacts of construction work on traffic, society, economy, and on-site safety during construction. Recent years have seen several developments towards the design of low-damage bridges and ABC. According to the results of conducted tests, these systems have significant potential to achieve the intended community resiliency objectives. Taking advantage of such potential in the standard design and analysis processes requires proper modeling that adequately characterizes the behavior and response of these bridge systems. To evaluate the current practices and abilities of the structural engineering community to model this type of resiliency-oriented bridges, the Pacific Earthquake Engineering Research Center (PEER) organized a blind prediction contest of a two-column bridge bent consisting of columns with enhanced response characteristics achieved by a well-balanced contribution of self-centering, rocking, and energy dissipation. The parameters of this blind prediction competition are described in this report, and the predictions submitted by different teams are analyzed. In general, forces are predicted better than displacements. The post-tension bar forces and residual displacements are predicted with the best and least accuracy, respectively. Some of the predicted quantities are observed to have coefficient of variation (COV) values larger than 50%; however, in general, the scatter in the predictions amongst different teams is not significantly large. Applied ground motions (GM) in shaking table tests consisted of a series of naturally recorded earthquake acceleration signals, where GM1 is found to be the largest contributor to the displacement error for most of the teams, and GM7 is the largest contributor to the force (hence, the acceleration) error. The large contribution of GM1 to the displacement error is due to the elastic response in GM1 and the errors stemming from the incorrect estimation of the period and damping ratio. The contribution of GM7 to the force error is due to the errors in the estimation of the base-shear capacity. Several teams were able to predict forces and accelerations with only moderate bias. Displacements, however, were systematically underestimated by almost every team. This suggests that there is a general problem either in the assumptions made or the models used to simulate the response of this type of bridge bent with enhanced response characteristics. Predictions of the best-performing teams were consistently and substantially better than average in all response quantities. The engineering community would benefit from learning details of the approach of the best teams and the factors that caused the models of other teams to fail to produce similarly good results. Blind prediction contests provide: (1) very useful information regarding areas where current numerical models might be improved; and (2) quantitative data regarding the uncertainty of analytical models for use in performance-based earthquake engineering evaluations. Such blind prediction contests should be encouraged for other experimental research activities and are planned to be conducted annually by PEER.
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Bourgeois, Paul, Bradley Kelley, John Petrusky, John Williamson, and Jonathan Yi. Transportation Analysis Exploring Alternative Shipping of Marine Expeditionary Brigade Forces to Seabase in Contingency Response Scenarios. Fort Belvoir, VA: Defense Technical Information Center, December 2015. http://dx.doi.org/10.21236/ad1009271.

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Jordan, Preston D., Curtis M. Oldenburg, and Grace W. Su. Analysis of Aquifer Response, Groundwater Flow, and PlumeEvolution at Site OU 1, Former Fort Ord, California. Office of Scientific and Technical Information (OSTI), February 2005. http://dx.doi.org/10.2172/877324.

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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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Barrera, Victor, Alexis Villacis, Jeffrey Alwang, and Luis Escudero. Open configuration options New Products, New Markets: Dragon Fruit in Ecuador. Inter-American Development Bank, January 2022. http://dx.doi.org/10.18235/0003964.

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Expanding incomes in Asian countries and changes in fresh-fruit value chains have created an important niche for producers of dragon fruit. Ecuadorean producers have responded and taken advantage of these evolving opportunities and market dynamism. By customizing their products to the specific demands of target markets and complying with the standards imposed by modern buyers, Ecuadorian exporters of dragon fruit demonstrate how challenges related to and opportunities in agri-food markets evolution can be met. This study documents the development of the dragon fruit market in Ecuador, with a special emphasis on the analysis of its value chain. The study additionally identifies and analyzes the main drivers of the success of the production and exports of the fruit and examines the main challenges and needs for improved public policies to promote sustainable growth of the sector. Findings are complemented with interviews conducted with the principal actors in the Ecuadorian dragon fruit industry, as well as a case study that involves several relatively recently formed dragon fruit-producing companies in the Amazon region of the country.
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Or, Etti, Tai-Ping Sun, Amnon Lichter, and Avichai Perl. Characterization and Manipulation of the Primary Components in Gibberellin Signaling in the Grape Berry. United States Department of Agriculture, January 2010. http://dx.doi.org/10.32747/2010.7592649.bard.

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Seedless cultivars dominate the table grape industry. In these cultivars it is mandatory to apply gibberellin (GA) to stimulate berry development to a commercially acceptable size. These cultivars differ in their sensitivity to GA application, and it frequently results in adverse effects such as decreased bud fertility and increased fruit drop. Our long term goals are to (1) understand the molecular basis for the differential sensitivity and identify markers for selection of sensitive cultivars (2) to develop new strategies for targeted manipulation of the grape berry response to GA that will eliminate the need in GA application and the undesirable effects of GA on the vine, while maintaining its desirable effects on the berry. Both strategies are expected to reduce production cost and meet growing consumer demand for reduced use of chemicals. This approach relies on a comprehensive characterization of the central components in the GA signaling cascade in the berry. Several key components in the GA signaling pathway were identified in Arabidopsis and rice, including the GA receptors, GID1s, and a family of DELLA proteins that are the major negative regulators of the GA response. GA activates its response pathway by binding to GID1s, which then target DELLAs for degradation via interaction with SLY, a DELLA specific F-box protein. In grape, only one DELLA gene was characterized prior to this study, which plays a major role in inhibiting GA-promoted stem growth and GA-repressed floral induction but it does not regulate fruit growth. Therefore, we speculated that other DELLA family member(s) may control GA responses in berry, and their identification and manipulation may result in GA-independent berry growth. In the current study we isolated two additional VvDELLA family members, two VvGID1 genes and two VvSLY genes. Arabidopsis anti-AtRGA polyclonal antibodies recognized all three purified VvDELLA proteins, but its interaction with VvDELLA3 was weaker. Overexpression of the VvDELLAs, the VvGID1s, and the VvSLYs in the Arabidopsis mutants ga1-3/rga-24, gid1a-2/1c-2 and sly1-10, respectively, rescued the various mutant phenotypes. In vitro GAdependent physical interaction was shown between the VvDELLAs and the VvGID1s, and GAindependent interaction was shown between the VvDELLAs and VvSLYs. Interestingly, VvDELLA3 did not interact with VvGID1b. Together, the results indicate that the identified grape homologs serve as functional DELLA repressors, receptors and DELLA-interacting F-box proteins. Expression analyses revealed that (1) VvDELLA2 was expressed in all the analyzed tissues and was the most abundant (2) VvDELLA1 was low expressed in berries, confirming former study (3) Except in carpels and very young berries, VvDELLA3 levels were the lowest in most tissues. (4) Expression of both VvGID1s was detected in all the grape tissues, but VvGID1b transcript levels were significantly higher than VvGID1a. (5) In general, both VvDELLAs and VvGID1s transcripts levels increased as tissues aged. Unfertilized and recently fertilized carpels did not follow this trend, suggesting different regulatory mechanism of GA signaling in these stages. Characterization of the response to GA of various organs in three seedless cultivars revealed differential response of the berries and rachis. Interestingly, VvDELLA3 transcript levels in the GA-unresponsive berries of cv. Spring blush were significantly higher compared to their levels in the highly responsive berries of cv. Black finger. Assuming that VvDELLA2 and VvDELLA3 are regulating berry size, constructs carrying potential dominant mutations in each gene were created. Furthermore, constitutive silencing of these genes by mIR is underway, to reveal the effect of each gene on the berry phenotype.
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Raja, Rameez Ali, Mustafa Kilic, Monica Prezzi, Rodrigo Salgado, and Fei Han. Implementation Study: Continuous, Wireless Data Collection and Monitoring of the Sagamore Parkway Bridge. Purdue University, 2022. http://dx.doi.org/10.5703/1288284317367.

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This report presents, in detail, the development and implementation of a wireless solar powered DAQ system for continuous real-time monitoring of the Sagamore Parkway Bridge using the data collected from strain gauges installed in the bridge pier and its foundation piles. The data analysis showed that there is no significant change in the load-settlement response of the bridge pier 3 years after its construction. The pile cap contribution in carrying the total load carried by the bridge pier is significant (about 20%). The hourly ambient temperature trends match with the incremental bending moments measured on the bridge pier and the piles. The daily temperature cycles also affected the load transferred between the piles within the pile group. The water level fluctuations of the Wabash River impacted the total load carried by the pier, such that a rise in water level resulted in slight drop in the total load carried by the bridge pier due to buoyant forces. The overall results of the bridge monitoring showed that the bridge has performed well since its construction.
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10

Newton, Ronald, Joseph Riov, and John Cairney. Isolation and Functional Analysis of Drought-Induced Genes in Pinus. United States Department of Agriculture, September 1993. http://dx.doi.org/10.32747/1993.7568752.bard.

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Abstract:
Drought is a common factor limiting timber production in the U.S. and Israel. Loblolly (Pinus taeda) and alleppo pine (Pinus halepensis) seedling survival is reduced when out planted, and growth and reproduction are often hindered by periodic droughts during later stages of tree development. Molecular and gene responses to drought stress have not been characterized. The objectives were to characterize drought-induced gene clones from these pines, to determine the effects of a growth regulator on drought tolerance, ABA levels, and drought-induced gene expression in alleppo pine, and to develop procedures for loblolly pine transformation. Nearly 20 cDNA clones influenced by gradual, prolonged drought stress have been isolated. Many of these have been shown to be induced by drought stress, whereas several others are down-regulated. These are the first drought-induced genes isolated from a pine species. Two genomic clones (lp5-1 and lp3-1) have been sequenced and characterized, and each has been found to be associated with a gene family. Clone lp5 appears to code for a cell wall protein, and clone lp3 codes for a nuclear protein. The former may be associated with changing the elastic properties of the cell wall, while the latter may be involved in signal transduction and/or protection from desiccation in the nucleus. Clone lp3 is similar to a drought-induced gene from tomato and is regulated by ABA. Several DNA sequences that are specific to induction during growth-retardation in alleppo pine by uniconazole have been identified. The active DNA species is now being identified. Promoters from genomic clones, lp3 and lp5, have been sequenced. Both are functional when fused with the gus reporter gene and transferred to other plant tissues as well as responding to a simulated drought stress. Through exodeletion analysis, it has been established that the promoter ABRE element of lp3 responds to ABA and that drought-induction of lp3 expression may also involve ABA. Stable tobacco transformants carrying either the lp5 or the lp3 promoter fused to a reporter gus gene have been obtained. The lp5lgus fusion was expressed at several stages of tobacco development and differentiation including the reproductive stage. There was no difference in phenotype between the transformants and the wild type. Embryogenesis procedures were developed for slash pine, but attempts to couple this process with gene transfer and plantlet transformation were not successful. Transformation of pine using Agrobacterium appears tractable, but molecular data supporting stable integration of the Agrobacterium-transferred gene are still inconclusive.
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