Characterization of Mean and Turbulent Flow over Complex Topography under various Inflow and Geometric Configurations

An experimental investigation of flow over a complex topography was undertaken to study the influence of inflow conditions including Reynolds number, upstream roughness, and inflow shear profile on mean and turbulent flow behaviour. Large-scale physical testing was employed over the escarpment of a hill, covering a Reynolds number range of 3.6×104 to 5.2×105. Measurements taken using Particle Image Velocimetry (PIV) and Cobra Probes were analyzed in terms of mean and turbulent statistics. Coherent structures were characterized through Proper Orthogonal Decomposition (POD). The results show that the Reynolds number had little effect on the flow behaviour, while the effect of changing upstream roughness was low to moderate. The modified inflow shear profile had a significant impact, greatly increasing turbulent kinetic energy. A sharper escarpment leading edge had the largest impact by far, significantly altering the flow dynamics. The turbulent flow behavior over the sharper escarpment was found to be similar to the classical case of forward-facing step

A High Elevation Record of the Star-nosed Mole (Condylura cristata) in Northeastern Vermont

A single male Star-nosed Mole, Condylura cristata, was captured in a rock pile at the top of East Mountain (elevation 1042 m; 3240 ft) in northeastern Vermont. Although known from high elevations (up to 1676 m; 5500 ft) in southern U.S. states, this species was not known to occur above 573 m (1880 ft) in the northern part of its range. This record is also important in confirming that C. cristata has some climbing ability when travelling above ground

An Exhibition in Student Leadership: The Academic Alternative Spring Break Experience

An Exhibition in Student Leadership: The Academic Alternative Spring Break Experience Ryan Kilpatrick and Elise Glidden Faculty Sponsor: Gail Faris, Women’s Center The Academic Alternative Spring Break program was founded at URI by Gail Faris six years ago in an effort to introduce students to the ideas of service learning, social justice, and what it means to be a concerned citizen. We were first introduced to this idea in the spring of 2009, when we took the course, Classroom without Borders: Academic Alternative Spring Break. It was about a year later that we both decided that our senior project would focus around this concept, but with an added component of student leadership. The idea of an Academic Alternative Spring Break may not be specifically related to our respective majors, but it is one that is both important in our lives and will help us in our future careers, whatever they may be. Our project is unique for two reasons. It is a joint project, and it is also the first AASB to be led by students at the University of Rhode Island. In order to prepare for this trip, we underwent leadership training, planned and coordinated the logistics of the trip, and played a key part in selecting the students who would participate in the pilot program. We also acted as teacher’s assistants in the Spring 2011 Classroom Without Borders in order to familiarize ourselves with the material covered in the class and with the six students we chose for our trip. The spring break trip itself was a culmination of our training and a test of our leadership skills. Our product, a student leadership guide, highlights the numerous steps undertaken to successfully plan and implement an AASB trip from a student leader perspective. It is our hope that this guide is informative and will be passed on and used by future student leaders at URI so that they will have the success that we did. Our presentation will portray the dedication and effort that went into our senior project before, during, and after the spring break trip. It will also include pictures and videos that further capture the spirit of our experience. It is our firm belief that the successful completion of this project has led to both the development of our leadership skills, and our passion to serve as concerned citizens of our local and national communities, and we see this project as a stepping stone to a life of servant leadership and a commitment to social justice

For wind turbines in complex terrain, the devil is in the detail

Abstract The cost of energy produced by onshore wind turbines is among the lowest available; however, onshore wind turbines are often positioned in a complex terrain, where the wind resources and wind conditions are quite uncertain due to the surrounding topography and/or vegetation. In this study, we use a scale model in a three-dimensional wind-testing chamber to show how minor changes in the terrain can result in significant differences in the flow at turbine height. These differences affect not only the power performance but also the life-time and maintenance costs of wind turbines, and hence, the economy and feasibility of wind turbine projects. We find that the mean wind, wind shear and turbulence level are extremely sensitive to the exact details of the terrain: a small modification of the edge of our scale model, results in a reduction of the estimated annual energy production by at least 50% and an increase in the turbulence level by a factor of five in the worst-case scenario with the most unfavorable wind direction. Wind farm developers should be aware that near escarpments destructive flows can occur and their extent is uncertain thus warranting on-site field measurements.</jats:p

Detection of Circumstellar Helium in Type Iax Progenitor Systems

We present direct spectroscopic modeling of 44 Type Iax supernovae (SNe Iax) using spectral synthesis code SYNAPPS. We confirm detections of helium emission in the early-time spectra of two SNe Iax: SNe 2004cs and 2007J. These He I features are better fit by a pure-emission Gaussian than by a P-Cygni profile, indicating that the helium emission originates from the circumstellar environment rather than the SN ejecta. Based on the modeling of the remaining 42 SNe Iax, we find no obvious helium features in other SN Iax spectra. However, $\approx 76\%$ of our sample lack sufficiently deep luminosity limits to detect helium emission with a luminosity of that seen in SNe 2004cs and 2007J. Using the objects with constraining luminosity limits, we calculate that 33% of SNe Iax have detectable helium in their spectra. We examine 11 SNe Iax with late-time spectra and find no hydrogen or helium emission from swept up material. For late-time spectra, we calculate typical upper limits of stripped hydrogen and helium to be $2 \times 10^{-3}$ M$_{\odot}$ and $10^{-2}$ M$_{\odot}$, respectively. While detections of helium in SNe Iax support a white dwarf-He star binary progenitor system (i.e., a single-degenerate [SD] channel), non-detections may be explained by variations in the explosion and ejecta material. The lack of helium in the majority of our sample demonstrates the complexity of SN Iax progenitor systems and the need for further modeling. With strong independent evidence indicating that SNe Iax arise from a SD channel, we caution the common interpretation that the lack of helium or hydrogen emission at late-time in SN Ia spectra rules out SD progenitor scenarios for this class.Comment: 43 pages, 55 figures. Accepted to MNRA