Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 45 for “"Modal Properties"”.
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Modal Properties and Spontaneous Emission Factor in Unstable-Resonator Semiconductor Lasers
… study has been carried out on the spectral, modal, and dynamical properties of a monolithic unstable-resonator semiconductor laser. Due to the large loss and the non-power-orthogonal nature of the transverse and longitudinal modes in the unstable resonator, the spontaneous emission factor, …
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Operational modal analysis and model updating with a cyclostationary input
… thesis addresses the problem of identifying the modal properties of a system based only on measurements of the system responses. This situation is frequently encountered in structural dynamics and is particularly relevant for systems where the in-service excitation is not artificially …
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Modal Analysis of General Cyclically Symmetric Systems with Applications to Multi-Stage Structures
This work investigates the modal properties of general cyclically symmetric systems and the multi-stage systems with cyclically symmetric stages. The work generalizes the modal properties of engineering applications, such as planetary gears, centrifugal pendulum vibration absorber (CPVA) systems, …
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Against Modalities: On the Presumed Coherence and Alleged Indispensability of Some Modal Notions
… that kinds (as opposed to individuals) have some modal properties. I argue that concerning typical kind-essentialist claims there is a non-trivial question—the transworld identity problem—about what the relevant kind terms are supposed to refer to in non-actual possible worlds. I reject several …
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Finite Element Modeling for Prediction of Low Frequency Floor Vibrations Due to Walking
… is justified by the current ability to predict modal properties. The first method is to predict the acceleration response using response history analysis with individual footstep forces as the loading function. The second method also uses response history analysis to predict the acceleration …
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Damage identification of unreinforced masonry structures based on vibration response
… (URM) buildings and the use of their distinctive modal properties in identifying damage. Numerical and physical models were used to analyse the applicability of system and damage identification techniques to non-slender URM buildings. Modal tests were conducted on two undamaged URM panels and an …
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MATLAB implementation of an operational modal analysis technique for vibration-based structural health monitoring
… in vibration-based SHM require knowledge of the modal properties of the structure under evaluation in its current state. The technique of operational modal analysis allows for these modal properties to be obtained by using the structure's dynamic response to ambient excitation. Using MATLAB, a …
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Linguistic modal conventionalism in the real world
… the prospects for a theory of metaphysical modality according to which modal truth is determined by conventional rules governing the terms in a natural language. I label this theory ‘linguistic modal conventionalism’, or ‘LMC’. My focus is on articulating and responding to a specific …
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Linguistic modal conventionalism in the real world
… the prospects for a theory of metaphysical modality according to which modal truth is determined by conventional rules governing the terms in a natural language. I label this theory ‘linguistic modal conventionalism’, or ‘LMC’. My focus is on articulating and responding to a specific …
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Dynamic Testing of an Elevated Water Tank
… objective of this thesis was to identify the modal properties of a pedesphere type, elevated water tank under different operating conditions relating to the water level in the tank. The research that was conducted included both numerical and experimental components. The numerical components …
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Semiconductor laser mode engineering via waveguide index structuring
… is often strongly influenced by the optical mode properties. In this work, dielectric waveguides and their guided modes have been simulated and analyzed as relevant to semiconductor diode lasers. The transverse refractive index structure of waveguides determines the modal field profiles and modal …
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Dynamics of High-Speed Planetary Gears with a Deformable Ring
… a FE/CM model. Planetary gears have structured modal properties due to cyclic symmetry, but these modal properties are different for spinning systems with gyroscopic effects and stationary systems without gyroscopic effects. Vibration modes for stationary systems are real-valued standing wave …
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Integrated Photonic Functions Using Optically Anisotropic Materials
… by the design, and lack tunability over their modal properties. In this thesis, we will investigate the prospects of optically anisotropic materials/structures as new emerging integrated platforms for tailoring the modal attributes of the waveguide modes. These concepts have been abundant in …
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Vertical -Cavity Surface -Emitting Lasers Operating in Photonic Crystal Waveguide Defect Modes
… accuracy of the resulting model in predicting modal characteristics is studied experimentally. The oxide aperture size is optimized to give maximum output power and lower threshold current, the role of loss in improving modal properties is investigated, and high speed operation is …
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The semantics and metaphysics of contingent identity
… objection to the Thesis, the objection from modal properties, and offer a response. The chapter concludes with an appendix devoted to criticizing Allan Gibbard's and H. W. Noonan's accounts of contingent identity and their relpies to the objection from modal properties. The chief weakness in …
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Excitation sources for structural health monitoring of bridges
… natural frequencies, mode shapes, and damping properties) as indicators of damage. While conceptually simple, considerable research is still required before VBDD methods can be applied reliably to complex structures such as bridges. VBDD methods require reliable estimates of modal parameters …
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A New Adaptive Array of Vibration Sensors
… described in this dissertation produces modal coordinates for monitoring and active control of structural vibration. The sensor array is constructed from strain-sensing segments. The segment outputs are transformed into modal coordinates by a sensor gain matrix. An adaptive algorithm for …
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Deflating Deflationism
… away) the fact that her view assigns the wrong modal properties to "true". As I show, the deflationist does not have the resources either to explain or to explain away this counter-intuitive feature of her view. Since, in addition, the arguments for deflationism do not support the adoption of a …
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Output-Only Experimental Modal Testing of Large Residential Structures and Acoustic Cavities Using Sonic Booms
In this thesis, an output-only experimental modal testing and analysis technique known as the Natural Excitation Technique (NExT) is examined for use with large residential structures and interior cavities. The technique which assumes a random, stationary input causing the response data is reviewed …
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Instrumentation and Dynamic Characterization of the Galena Creek Bridge
… conducted to characterize the dynamic properties of the structure in its baseline condition.A system of accelerometers was installed for this project in the superstructure of the bridge and several experiments were performed to determine its basic dynamic characteristics. Live loading …
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