Matching Items (6)

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Investigation into the von Karman Vortex Street and the Relationship Between Reynolds and Strouhal Numbers

Description

This experiment used hotwire anemometry to examine the von Kármán vortex street and how different surface conditions affect the wake profile of circular airfoils, or bluff bodies. Specifically, this experiment

This experiment used hotwire anemometry to examine the von Kármán vortex street and how different surface conditions affect the wake profile of circular airfoils, or bluff bodies. Specifically, this experiment investigated how the various surface conditions affected the shedding frequency and Strouhal Number of the vortex street as Reynolds Number is increased. The cylinders tested varied diameter, surface finish, and wire wrapping. Larger diameters corresponded with lower shedding frequencies, rougher surfaces decreased Strouhal Number, and the addition of thick wires to the surface of the cylinder completely disrupted the vortex shedding to the point where there was almost no dominant shedding frequency. For the smallest diameter cylinder tested, secondary dominant frequencies were observed, suggesting harmonics.

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Date Created
  • 2017-05

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Human Auditory Biases Match Natural Regularities Found With Animal Calls

Description

Human perceptual dimensions of sound are not necessarily simple representations of the actual physical dimensions that make up sensory input. In particular, research on the perception of interactions between acoustic

Human perceptual dimensions of sound are not necessarily simple representations of the actual physical dimensions that make up sensory input. In particular, research on the perception of interactions between acoustic frequency and intensity has shown that people exhibit a bias to expect the perception of pitch and loudness to change together. Researchers have proposed that this perceptual bias occurs because sound sources tend to follow a natural regularity of a correlation between changes in intensity and frequency of sound. They postulate that the auditory system has adapted to expect this naturally occurring relationship to facilitate auditory scene analysis, the tracking and parsing sources of sound as listeners analyze their auditory environments. However, this correlation has only been tested with human speech and musical sounds. The current study explores if animal sounds also exhibit the same natural correlation between intensity and frequency and tests if people exhibit a perceptual bias to assume this correlation when listening to animal calls. Our principal hypotheses are that animal sounds will tend to exhibit a positive correlation between intensity and frequency and that, when hearing such sounds change in intensity, listeners will perceive them to also change in frequency and vice versa. Our tests with 21 animal calls and 8 control stimuli along with our experiment with participants responding to these stimuli supported these hypotheses. This research provides a further example of coupling of perceptual biases with natural regularities in the auditory domain, and provides a framework for understanding perceptual biases as functional adaptations that help perceivers more accurately anticipate and utilize reliable natural patterns to enhance scene analyses in real world environments.

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Date Created
  • 2014-05

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Item Analysis of the Late Adolescent Home Observation for Measure of the Environment Inventory

Description

This thesis was an analysis of items in the Late Adolescent Home Observation for Measure of the Environment (LA HOME) after the first wave of N = 138 interviews. The

This thesis was an analysis of items in the Late Adolescent Home Observation for Measure of the Environment (LA HOME) after the first wave of N = 138 interviews. The purpose of this project was to learn how to utilize a statistical software such as SPSS to analyze items and interpret results. Frequency analysis, inter-rater reliability (IRR), correlation analysis, internal consistency using Cronbach's alpha, and feedback from research assistants were considered when deciding which items should be eliminated from the measure. After running these analyses, ten items were suggested for deletion including: clean, adolescent's room allows for privacy, reference materials, news, family encourages adolescent to think independently, community service, parent knows where adolescent spends time, weekly household responsibilities, school/career planning, and dentist. Future interviews generating a larger sample size as well as discussions and subsequent revisions to the manual will clarify additional items that may be eliminated from the final version of the instrument.

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Date Created
  • 2015-05

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E-Cigarette and Subsequent Smoking Use and Relationship to E-Cigarette Quit Attempts Among College Students

Description

The present study investigated the student population at Arizona State University to: (1) assess how electronic cigarette (e-cigarette) use is associated with subsequent smoking (cigarette, hookah, cigarillo, smokeless tobacco, marijuana)

The present study investigated the student population at Arizona State University to: (1) assess how electronic cigarette (e-cigarette) use is associated with subsequent smoking (cigarette, hookah, cigarillo, smokeless tobacco, marijuana) use; (2) investigate the relationship of e-cigarette use with non-electronic smoking cessation, and vice versa; and (3) compare how e-cigarette use is associated with cessation of non-electronic smoking. Based on previous related research and tools, the cross-sectional study included an anonymous online screening, followed by a survey that assessed e-cigarette use and non-electronic smoking, e-cigarette withdrawal and cessation, and non-electronic smoking quit attempts. Participants (N=65) were recruited via flyer advertisements, social media advertisements, ASU online advertisements, and email notices. Major findings of this study include: Participants who used non-electronic smoking primarily used cigarettes or marijuana; participants who used both electronic and non-electronic smoking more frequently used e-cigarettes than non-electronic forms; and participants who previously attempted e-cigarette cession believe that they will successfully withdraw from e-cigarette use in the future, by either using marijuana or not using non-electronic smoking in the future. Based on these findings, nurses should assess all youth and young adults for e-cigarette “core constructs”; provide evidence-based interventions; and encourage future, successful e-cigarette cessation.

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Date Created
  • 2020-05

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Examining sound and urban-desert differences in the acoustic properties of Northern Mockingbird (Mimus polyglottus) calls as it relates to species survival

Description

Human activity produces ambient noise that potentially alters species’ abilities to communicate with each other—among other impacts. Given that birds are known to be sensitive to structural changes in

Human activity produces ambient noise that potentially alters species’ abilities to communicate with each other—among other impacts. Given that birds are known to be sensitive to structural changes in habitat and highly communicative through sound, it is beneficial to understand how changing acoustic ecologies and ambient noise impact birds’ ability to communicate in their respective environments. In this study, mockingbird calls from an urban, desert, and intermediate study site were recorded and analyzed for differences in acoustic properties. Acoustic properties such as frequency and amplitude differed significantly across sites as it was determined that mockingbirds in urban areas increase both the peak frequency and amplitude of their calls in order to communicate. This study identifies what these changes in acoustic properties mean in relation to the survival and conservation of birds and concludes with recommendations for novel research.

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Date Created
  • 2019-05

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Early Wing Structural Design for Stiffness and Frequency Response

Description

This paper describes an effort to bring wing structural stiffness and aeroelastic considerations early in the conceptual design process with an automated tool. Stiffness and aeroelasticity can be well represented

This paper describes an effort to bring wing structural stiffness and aeroelastic considerations early in the conceptual design process with an automated tool. Stiffness and aeroelasticity can be well represented with a stochastic model during conceptual design because of the high level of uncertainty and variability in wing non-structural mass such as fuel loading and control surfaces. To accomplish this, an improvement is made to existing design tools utilizing rule based automated design to generate wing torque box geometry from a specific wing outer mold-line. Simple analysis on deflection and inferred stiffness shows how early conceptual design choices can strongly impact the stiffness of the structure. The impacts of design choices and how the buckling constraints drive structural weight in particular examples are discussed. The model is then carried further to include a finite element model (FEM) to analyze resulting mode shapes and frequencies for use in aeroelastic analysis. The natural frequencies of several selected wing torque boxes across a range of loading cases are compared.

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Date Created
  • 2018