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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 17 of 17 for “"Frequency sweeps"”.
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Reinforcement of Hydrogels via Polyacrylic Acid Nanoparticles Induced Calcium Carbonate Crystallization
… storage modulus was evaluated using rheologic frequency sweeps to determine how the material's properties change after the addition of calcium ions and after the crystallization of CaCO3. The next system that was evaluated was the effect of both the nanoparticles and carboxylic acid …
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A magnetorheological study of single-walled and multi-walled carbon nanotube dispersions in mineral oil and epoxy resin.
… studied using a parallel plate rheometer. Strain sweeps, frequency sweeps, magneto sweeps and steady shear tests were conducted in various magnetic fields. G', G", h* and ty increased with increasing magnetic field, which was partially attributed to the increasing degree of the alignment of …
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A numerical simulation of multiple-shaker model testing
… the associated modes of vibration. Narrow-band frequency sweeps were used to determine the purity of isolated modes through the use of coincident-quadrature response plots in the Argand plane. In addition, modal energies of partially isolated modes were examined for the effects of interfering …
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Viscoelastic Modeling of Straight and Modified Binders at Intermediate and High Temperatures
… ranging from 5 to 75°C. Prior to the frequency sweeps, strain sweeps were performed to establish the linear viscoelastic region. Results indicated a strong susceptibility to the defined strain at intermediate temperatures; however, strain susceptibility was less pronounced at high …
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Automated SG-DBR Tunable Laser Calibration Optimized for Optical Coherence Tomography Applications
… a tunable laser source that exhibits linear frequency sweeps, large frequency spans, and high repetition rates. This work accomplishes this by using four synchronized waveforms sent to the input of a Sampled Grating-Distributed Bragg Reflector (SG-DBR) laser. Three mirrors control the …
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Solid state amperometric sensor for the in-situ monitoring of slag composition and transport properties
… slags. Applied DC potential steps and impedance frequency sweeps at applied DC potentials were shown to clearly distinguish between slags containing different quantities of FeOx while demonstrating similar oxygen activities - an improvement over conventional oxygen sensor technology. The …
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Additive Manufacturing of Commercial Polypropylene Grades of Similar Molecular Weight and Molecular Weight Distribution
… modulus crossover point via small oscillatory frequency sweeps. We specifically show that a relatively higher crossover frequency will correlate with improved interlayer adhesion and reduced warpage in printed structures. However, this improvement is accompanied by a tradeoff, resulting in …
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Impedance spectroscopy for the characterization of swine reproductive states
… machine learning to examine data acquired from a frequency sweeping electrical impedance spectrometer taking readings from sows in order to potentially determine if the resultant data can be used to predict a sow's date of estrus, date of farrowing, and if the inseminated sow has become pregnant. …
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Simulation, Modeling, and Characterization of the Wakes of Fixed and Moving Cylinders
… the cylinder motion (direction, amplitude, and frequency) by using modern methods of nonlinear dynamics. The possible responses can be period-one, periodic with large period, quasiperiodic, or chaotic. Moreover, we found that the route to chaos is torus breakdown. We investigated how four …
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Adaptive methods for linear dynamic systems in the frequency domain with application to global optimization
… of the design and its modifications are frequency dependent matrices. Such matrices typically arise due to finite element analysis as well as other modeling techniques. Computing performance metrics related to steady-state forced response, also known as performing a frequency sweep, …
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Modeling of the linear viscoelastic response of polymer modified asphalt binders at intermediate and high temperatures
… range of response through performing stress sweeps, a series of frequency sweeps was carried out. Investigation of the resulting isothermal response curves indicated that simple time-temperature superposition is applicable, and dynamic master curves can be constructed by empirical …
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Energy Harvesting toward the Vibration Reduction of Turbomachinery Blades via Resonance Frequency Detuning
… blade vibrations, namely resonance frequency detuning. In contrast with the bulk of energy harvesting research, this effort is not focused on maximizing the power output of the system, but rather providing the low power levels required by resonance frequency detuning. The demands of …
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Controlling Cocontinuous Polymer Blends with Nanofillers Jammed at the Interface
… with rheology, we combined rheology time sweeps with morphology information from confocal microscopy, scanning electron microscopy and transmission electron microscopy. We found that morphology coarsening results in shrinkage of interfacial area and jamming of interfacial nanofillers. The …
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Parametric Yield and Tolerance Optimisation of Electromagnetic Devices using Feature-based Non-Linear Partial Least Squares Polynomial Chaos Expansion Surrogates
… analysis method is successfully applied to a mid-frequency aperture array (MFAA) log periodic dipole antenna (LPDA) with 93 geometrical variables and an 18-variable KA band ridge waveguide filter terminated with a Vivaldi antenna. This allows for accurate yield and sensitivity estimates using 24 …
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On the dynamics and interparticle forces of electrostatically stabilized colloidal suspensions
… electric fields. Through simulations involving frequency sweeps and chirp signals, we discerned that the dynamic response of these concentrated charged soft matter systems is best understood through the lens of two distinct transport regimes—characterized by short- and long-time responses. This …
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A study of the mechanical properties and the equilibrium nature of the blend of thermotropic liquid crystalline copolyesters
… pass and the 70/30 PHB/ PET samples, dynamic frequency sweeps were performed in the RMS at different temperatures. At a given frequency, the complex viscosity, storage modulus and loss modulus increased with an increase in the number of extrusion passes. This increase is unexpected. A number …
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Fundamental studies of sourdoughs fermented with Weissella cibaria and Lactobacillus plantarum: influence on baking characteristics, sensory profiles and in vitro starch digestibility of gluten-free breads
The application of sourdough can improve texture, structure, nutritional value, staling rate and shelf life of wheat and gluten-free breads. These quality improvements are associated with the formation of organic acids, exopolysaccharides (EPS), aroma or antifungal compounds. Initially, the …