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 52 for “"Impact events"”.
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Modeling target rock composition of two impact events
… target rock and bolide material during meteorite impacts, represent a unique window into this time. This study models target rock compositions of two Archean-Paleoproterrozoic impact events, represented by the Dales Gorge–Kuruman (~2.49 Ga) and Paraburdoo–Reivilo (~2.57 Ga) spherule layer pairs. …
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The sensitivity of aircraft emergency locator transmitters to non-distress impact events
… locator transmitters to these non-distress impact events.</p> <p>This research project consisted of two (2) main tasks: creation of a database of non-distress deceleration pulses and investigation of what types of non-distress events cause activation. In creating a database of non-distress …
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Quantifying various thunderstorm characteristics during high impact events using radar and satellite observations
… (sub-daily/hourly) and can have destructive impacts, especially over urban areas. Therefore, it is vital to understand the nature of changes in these extremes to reduce the risk of their destructive impacts on cities. The overarching goal of this thesis is to quantify various storm …
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Time-resolved spectroscopic characterization of ballistic impact events in polymer and nanocomposite materials
… during and immediately following a ballistic impact event is not currently well understood. The dynamic mechanical responses of materials experiencing ballistic shock-loading conditions are quite complex, with large amplitude compressions resulting in strain rates in excess of 106 s-1 and …
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Experimental and Computational Methods for Investigating Automotive Door Closure Sounds
… operation of an automotive door closure at two impact speeds using experimental and computational methods. The impact speeds were 0.851m/s and 1.179m/s. Transient sound pressure measurements from five different door closure mechanisms were collected in a semi-anechoic chamber using a …
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Implementation of viscoelastic Hopkinson bars
… our understanding of their role during blast or impact events. Testing these soft or low impedance materials using metallic bars in a split Hopkinson pressure bar setup, poor signal to noise ratios and impedance mismatching occur. One solution is to use polymeric Hopkinson bars. In this …
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Effect of Rule Changes Occurring Between 2003 and 2016 on Head Impact Frequency and Brain Strain Magnitude In North American Professional Ice Hockey
Head impacts can result in various levels of brain trauma, from mild to severe, and often result in long lasting effects on human brain function (McAllister & McCrea, 2017; Sollmann et al., 2018). Over the past two decades alone the National Hockey League (NHL) has made several rule changes to the …
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Development of a reinforcing fibre light-guide for use as a damage sensor within composite structures
… would give a direct indication of the extent of impact damage in a composite. This was achieved by using glass reinforcing fibres to produce a light-guide, which was embedded within a composite laminate. The laminate was then subjected to impact events or bending stresses of sufficient magnitude …
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When sticky fluids do and do not stick: yield-stress fluid drop impacts
… to experimentally study yield-stress fluids impacting three types of surfaces that exhibit distinct and fascinating behaviors: coated surfaces, permeable surfaces, and hot surfaces. A variety of common materials such as peanut butter, toothpaste, paints, foams, printing ink, cement, and …
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Analytical behaviour of FRP strengthened reinforced concrete beams under low velocity impact load incorporating rate dependant material constitutive models
… strengthened RC beams subjected to low velocity impact events. Furthermore, many of the Finite Element (FE) analysis models developed in these studies yielded results that were inconsistent with the test data. Key shortcomings of these models relate to a lack of definition of the FRP-concrete …
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Self-healing of delamination damage in glass/epoxy composites using catalyst functionalized fibers
… areas because of susceptibility to damage from impact events in directions transverse to the direction of fiber reinforcement. Damage occurring from transverse impact events is multi-dimensional, difficult to predict and visually difficult to detect. This complexity leads to more expensive …
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Integrating Gradient Boosting and Generative Models: Hybrid Approach to Address Class Imbalance and Evaluation Gaps in Real-World Systems
… detection pipelines in domains where rare, high-impact events must be detected while meeting strict operational demands.
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Finite Element Modeling of Delamination Damage in Carbon Fiber Laminates Subject to Low-Velocity Impact and Comparison with Experimental Impact Tests Using Nondestructive Vibrothermography Evaluation
… common when composite laminates are subject to impact loading.</p> <p>Various finite element methods for analyzing delamination exist. In this research, a modeling strategy based on contact tiebreak definitions in LS-DYNA<sup>®</sup>was used. A finite element model of a low-velocity impact event …
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Migration, nativism, and party system change in Western Europe
… identities generated by unanticipated, high impact events, such as a severe economic downturn, terror attack or ethnic riot. These "shocks" represent a perceived threat to the economic security, physical safety or group position of some individuals, increasing the attention (salience) they …
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Identifying Risk Exposure in a Global Retail Supply Chain
… for addressing low-probability and high-impact events, such as a global pandemic. Therefore, we explore the development and application of a risk model based on the principles of time-to-survive (TTS) and time-to-recovery (TTR). We examine two definitions for TTS. In a supply disruption …
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The effects of tensile preloads on the impact response of carbon/epoxy laminates
Low velocity drop weight impact tests were conducted on carbon/epoxy laminates under various magnitudes of uniform tensile stress. The composite plates were 8 ply (+45,0,- 45,90)<sub>s</sub> laminates supported in a clamped-clamped/free-free configuration. Tensile preloads from near zero to …
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The Chicxulub impact event and the environmental catastrophe at the end of the Cretaceous Period
Impact events may have affected the evolution of life on Earth. The mass extinction event at the end of the Cretaceous Period, which includes the demise of the dinosaurs, has been linked to the large impact event that produced the Chicxulub structure located in the Yucatán Peninsula, Mexico. …
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Infrared Spectra Analysis of Thermally Altered Iron Phyllosilicates and the Implications for Mars
… at temperatures selected to mimic lava flows and impact events. Following heating, each sample was placed in a Fourier Transform Infrared (FT-IR) spectrometer to collect the near- and mid-infrared spectra. The spectra allowed for these terrestrial analogs to be analyzed with regards to how their …
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Resiliency Oriented Scenario Generation Framework for Natural Gas Infrastructure
Traditionally, NG's impact on power supply has been studied from a reliability perspective, focusing on frequent and low-impact events. Furthermore, power-NG interdependence has been considered at a local scale, with few possibilities for extension to future climate impacts. Our work contributes to …
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