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 20 for “"rate dependency"”.
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Investigating the loss of crystal structure in carbohydrate materials
Twenty-five carbohydrate type materials were screened using differential scanning calorimetry (DSC) to characterize the heating rate dependence of their melting temperature. Three heating rates were used: 1, 5 and 25°C/min. Based on previous research, it was hypothesized that if the material had …
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Fatores que podem influenciar o saldo financeiro do regime geral de previdência social brasileiro
… wage, National Index of Consumer Prices, Selic rate, dependency ratio of the elderly, informal employment, and income the usual, have had significant results, thus confirming that these variables influence the cash balance of the General Regime of Social security.
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Effects of morphine, d-amphetamine, and food deprivation on temporally organized behavior
… in the peak procedure. Both drugs produced clear rate-dependent effects on behavior in both procedures. In Experiment 2, FI performance was assessed both alone and with a concurrently available variable-interval (VI) schedule to determine whether drugs would cause a pigeon to leave a potential …
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Crack path selection and shear toughening effects due to mixed mode loading and varied surface properties in beam-like adhesively bonded joints
… the growth of damage and cracks, loading rate dependency of crack propagation, and the effect of mixed mode fracture loading scenarios on crack path selection. This dissertation involves analytical, numerical, and experimental evaluations of crack propagation in several adhesive joint …
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Effects of Thickness and Indenter Tip Geometry in Nanoindentation of Nickel Films
… mechanical properties of thin films on substrates and bulk materials, and the effect of geometrically different indenters (Berkovich, cubecorner, and conical). X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), and atomic force microscopy …
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Investigation of Toughening Mechanisms in the Fracture of Asphalt Concrete Using the Clustered Discrete Element Method
… of the morphology of the material is incorporated into the DEM model using high-resolution imaging and image analysis software. The bulk properties and fracture parameters of multi-phase are obtained from experiments and calibration procedure. The two-dimensional clustered DEM method is …
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Material characterization and modeling for piezoelectric actuation and power generation under high electromechanical driving levels
… material behaviors, one- and three-dimensional rate dependent nonlinear constitutive models based on thermodynamic potentials for PZT-5H and PZT-5A piezoelectric materials were then developed. An internal variable, net remnant polarization D*, was used to simulate the hysteric behaviors of …
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Investigation of thermal decomposition as the cause of the loss of crystalline structure in sucrose, glucose, and fructose
… of sugar used. Thus, it is important to accurately and completely characterize the sugars prior to use in specific applications. Melting has been commonly used for sugar characterization because it is an easy and quick property to measure, yet is usually repeatable and robust. In general, …
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Temperature dependent dynamic response of open-cell polyurethane foams
… These experiments were conducted under strain rates of 10$^2$ s$^{-1}$ and under temperature conditions ranging from -20 to 40\textdegree{C}. This temperature range was chosen to simulate desert and arctic conditions, with a strain rate regime chosen to represent loads that would occur often …
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Determinants of Abuse-Related Effects of Monoamine Releasers in Rats
… serotonin. These data were then submitted to a rate-dependency analysis. Here, we found that all compounds produced rate-dependent effects, but that the profile of these effects varied with a compound’s selectivity for dopamine versus serotonin. Next, the mechanism by which serotonin exerts it …
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Physically based multiscale-viscoplastic model for metals and steel alloys: theory and computation
… In general, metal structures display a strong rate- and temperature-dependence when deformed non-uniformly into the inelastic range. This effect has important implications for an increasing number of applications in structural and engineering mechanics. The mechanical behavior of these …
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Micromechanics of ultra-high molecular weight polyethylene fibre composites
… punches. It is shown that the punch penetrates the composites without fibre fracture but by the formation of mode-I cracks along the fibre directions. The results indicate that the high penetration resistance of the composites by sharp-tipped punches is attributed to the high toughnesses …
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Mechanical behavior of individual type I collagen fibrils
… cyclic loading/recovery experiments, and strain rate tests spanning six decades of strain rates in the range 10-3 – 102 s-1. Experiments were conducted with reconstituted type I calfskin collagen fibrils which were isolated from buffer and after drying were adhesively attached to a …
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Implementation and evaluation of a recently developed rate-dependent effective stress soil model 'MIT-SR'
Reliable modeling of rate-dependency in soil properties remains a major challenge for accurate solutions of many geotechnical problems. Although there are many sources of experimental data concerning rate dependent properties of clays, most pre-existing soil models have been found to have severe …
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The electrophysiological and molecular effects of chronic beta-adrenoceptor antagonist therapy on human atrium
… atrial K+ currents, including voltage, time and rate dependency, differ between patients treated and not treated with a β-blocker as a result of altered expression of ion channel pore-forming and accessory subunits. Human atrial myocytes were isolated enzymatically from right atrial appendage …
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Analisi teorica, numerica e sperimentale dei processi di grandi deformazioni nei materiali duttili
… cinematic and isotropic hardening.,strain rate dependency, thermal effects, the loosing of the original mechanical properties, are just a part of a bigger list of factors that affect the deformation properties of a body, leading to many complications in the theoretical analysis of solids …
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Investigating the thermal behavior differences between beet and cane sugar sources
… and cane sucrose sources also exhibited heating rate dependency, with Tmonset values for both small and large peaks increasing as heating rate increased. Overall, however, the degree of thermal stability, based on results from an ampule heating study, was much greater for beet compared to cane …
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Thermo-mechanical characterisation of energetic materials for additive manufacture
… time step approach to better investigate the rate dependency observed in the experiment. Following the presentation and discussion of the experimental work undertaken, overall conclusions are presented and discussed with a particular emphasis on the implications for additive manufacturing …
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Experimental investigation of damage evolution during strain burst in brittle rocks for deep mines
… high confining pressure and various loading rate on the overall mechanical behaviour of highly brittle granitic rocks leading to strain burst. Strain burst is related to the elastic stored strain energy and how this stored energy is released during the unstable spontaneous failure. Therefore, …
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The thermodynamics, kinetics and modelling of fast-charging lithium-ion batteries featuring crystallographic shear niobium metal oxide anodes
… with a nominal potential around 1.6 V, charging rates >5C and a cycle-life projected over 10,000 cycles. Chapter 1 shows that the exact potential can be tuned further by changing the average oxidation state through substitution of Nb<sup>5+</sup> with for example W<sup>6+</sup> or …