A weak-scattering model for turbine-tone haystacking outside the cone of silence

We consider the scattering of sound by turbulence in a jet shear layer. The turbulent, time-varying inhomogeneities in the flow scatter tonal sound fields in such a way as to give spectral broadening, which decreases the level of the incident tone, but increases the broadband level around the frequency of the tone. The scattering process is modelled for observers outside the cone of silence of the jet, using high-frequency asymptotic methods and a weak-scattering assumption. An analytical model for the far-field power spectral density of the scattered field is derived, and the result is compared to experimental data. The model correctly predicts the behaviour of the scattered field as a function of jet velocity and tone frequency<br/

A weak scattering model for tone haystacking

The scattering of sound by turbulence in a jet shear layer is considered. Spectral broadening or 'haystacking' is the process whereby the turbulent, time-varying inhomogeneities in the flow scatter tonal sound fields, which decreasesthe level of the incident tone, but increases the broadband level around the frequency of the tone. The scattering process is modelled analytically, using high-frequency asymptotic methods and a weak-scattering assumption. Analytical models for the far-field spectral density of the scattered field are derived for two cases: (1) any polar angle including inside the cone of silence; (2) polar angles outside the cone of silence. At polar angles outside the cone of silence, the predictions from the two models are very similar, but using the second model it is considerably simpler to evaluate the far-field spectral density. Simulation results are compared to experimental data, albeit only at a polar angle of 90º. The model correctly predicts the behaviour of the scattered field as a function of jet velocity and tone frequency. Also simulations at other polar angles and a parametric study are presented. These simulations indicate how the 'haystacking' is predicted to vary as a function of the polar angle, and also as a function of the characteristic length, time and convection velocity scales of the turbulence contained in the jet shear layer

Sport psychologists’ experiences of organizational stressors

This study extends stress research by exploring sport psychologists’ experiences of organizational stressors. Twelve accredited sport psychologists (6 academics and 6 practitioners) were interviewed regarding their experiences of organizational stress within their jobs. Content analysis involved categorizing the demands associated primarily and directly with their occupation under one of the following general dimensions: factors intrinsic to sport psychology, roles in the organization, sport relationships and interpersonal demands, career and performance development issues, and organizational structure and climate of the profession. A frequency analysis revealed that academics (ΣAOS = 201) experienced more organizational stressors than practitioners (ΣPOS = 168). These findings indicate that sport psychologists experience a wide variety of organizational stressors across different roles, some of which parallel those found previously in other professions. The practical implications for the management of stress for sport psychologists are discussed

Prediction of the acoustic impedance of duct liners

Recent research which contributes to the prediction of the acoustic impedance of duct liners is reviewed. This review includes the linear and nonlinear properties of sheet and bulk type materials and methods for the measurement of these properties. It also includes the effect of grazing flow on the acoustic properties of materials. Methods for predicting the properties of single or multilayered, point reacting or extended reaction, and flat or curved liners are discussed. Based on this review, methods for predicting the properties of the duct liners which are typically used in aircraft engines are recommended. Some areas of needed research are discussed briefly

Three Essays in Regional Taxation

This dissertation looks at the role that geographically limited taxation and the behavioral response of economic agents to different forms of regional taxation. While geographic taxation is typically thought to be confined to state and local taxes, federal tax policy can also create designated areas that receive preferential tax treatment. In this dissertation, both types of regional taxation are examined and are unified under common themes such as tax mobility and the definition of the tax base. In chapter 2, I examine the important effect of how the location of high income earners employment is influenced by taxes in the state of employment. Previous literature has focused on the residency decision of high income earners, but that is not the only margin that matters, as in both the United States and the European Union taxes are instead due where income is earned. Using the universe of PGA tour participants from 1970-2018, I estimate the participation response to golfers with respect to a change in their effective tax rate. In the baseline specification, I find a tax participation elasticity of 0.32 and for those in the top 25 percent of prior year earnings, consistent with the superstar effect, find a larger elasticity of .82. I also find that federal taxes play a minimal role in the tax response of golfers and the primary effect is driven by changes in state taxes, suggesting that golfers reallocate their income away from low tax states towards higher tax states instead of a true labor supply response. In Chapter 3, I look at an important distinction in tax policy, whether tax base changes are different than an equivalent change in the tax rate. This is in the context of a gradually narrowing consumption tax base that has largely left both physical and digital services out of the tax base. Using variation in food tax inclusion and the food tax rate combined with data from the Nielsen Corporation on the retail sale of food, I find that a one percent increase in the gross price of food decreases sales in border areas by less than one percent using a border pair identification strategy in both a static and dynamic setting. In addition I estimate the effect of removing food from the tax base using removals from West Virginia and South Carolina and find no additional effects beyond an equivalent rate reduction, suggesting among this very specific population, there is no meaningful difference between the two. This is largely suggestive that broadening the tax base would provide large gains in revenue with little loss in efficiency. Chapter 4 explores whether place-based policies, which are geographically defined programs that provide special benefits to particularly poor neighborhoods lead to persistent effects once the programs expire. This question is important as the United States as well as other countries continue to invest in place-based policies without knowing the long run impacts. Using restricted access American Community Survey and the expiration of Renewal Communities relative to Empowerment Zones, I find little evidence for a permanent improvement within Renewal Communities, with RC employment, income, and rent decreasing relative to the continuing Empowerment Zones. However, I do find that for those individuals who live and work in the zone, there is no subsequent decline in employment or income, suggesting that there is heterogeneity in persistence. Given that the newest iteration of place-based policies in the United States, Opportunity Zones, largely shares the same benefit structures as Renewal Communities it is unlikely that we will see lasting benefits from it\u27s implementation

How American Sign Language-English Interpreters Who Can Hear Determine Need for a Deaf Interpreter for Court Proceedings

This study investigates how and when hearing interpreters in the United States decide there is a need for a Deaf interpreter in court proceedings. Previous publications have strongly suggested that it is best practice to work with a Deaf interpreter for specific situations (NCIEC, 2007). In this study, the author utilized two frameworks: Brennan & Brown’s (1997) Equality before the Law, and Mathers’ (2009) Deaf interpreters in court: an accommodation that is more than reasonable, to design this study which brings to light the criteria used by hearing ASL-English interpreters when calling upon Deaf interpreters. This research also explores the hearing interpreter’s view of the Deaf interpreter and allows for discussion about the experience of working as the hearing member of a Deaf-hearing team in the courtroom. Findings suggest that hearing interpreters are generally in alignment with best practices for working with Deaf interpreter specialists, but significant inconsistencies and barriers remain. Further research into this configuration and its accompanying dynamics is needed

Shifting Focus: The Role of Visual Literacy in the Twenty-First Century English Classroom

Ultimately, the English language arts classroom seeks to help make students “literate” members of society. Due to the dominance of images in twenty-first century communication, the term “literate” has also slowly shifted to include an individual’s ability to effectively and accurately communicate with verbal text as well as with visual images and symbols. Although students are native image-viewers, they are not able to be image-readers without instruction and training on how to critically “read” images. Therefore, an English teacher’s literary curriculum is not strictly bound to the written and spoken word. Instruction in reading and writing written texts are vital skills for students to learn, and English curriculums must continue to teach students how to effectively communicate using verbal language. However, English language arts curriculums should adopt a more balanced approach between verbal and visual literacy skills. This thesis examines a shift that has occurred in the way that we communicate as a culture, it defends the definitions of “literacy” and “literature” to include both textual and visual language, it highlights foundational learning objectives for the English classroom, and it presents various activities that educators may use to teach visual language skills. In order to better prepare students to work, communicate, and live in a visually rich world, English language arts curriculums must include extensive instruction in both verbal and visual languages