A compact spectroradiometer for solar simulator measurements

Compact spectral irradiance probe has been designed and built which uses wedge filter in conjunction with silicon cell and operational amplifier. Probe is used to monitor spectral energy distribution of solar simulators and other high intensity sources

Branding Against Closure: Neighborhood Schools And The Management Of Risky Futures

Philadelphia is one of many distressed American urban school districts, from Chicago to New Orleans, that has embraced market-based responses like school closures to tackle entrenched problems of funding and academic performance. While urban districts have increasingly appropriated closures-as-policy, little scholarship interrogates the sweeping social and organizational changes in governance and praxis that schools make when faced its explicit ultimatum: compete or close. Applying a framework developed in the anthropologies of branding and value, this dissertation explores school leaders’ fraught responses to imminent closure as they attempted to make their “value” legible in an expanding marketplace of school choice. Through a three-year ethnographic case study of an ethnically diverse neighborhood school slated for closure, I examine how the school’s strategies to remain open hinged on the selective enrollment and retention of students deemed “valuable” to their imagined brand. As these practices indexed raced notions of “value”, I analyze how school branding processes deepen racialized disparities in educational provision. Methods include over 200 semi-structured interviews with students, teachers, and administrators, participant observation in classrooms, district offices and meetings, and document analysis. As closures continue to threaten urban public schools across the United States, this study uniquely captures the dilemmas that surface in educational practice and philosophy when schools prioritize the business of survival over the business of educating. Further, I contribute to emergent literatures in educational commodification and marketization by explaining how school branding, prompted by closure threats and competition for school survival, extend inequities in opportunity structures for vulnerable youth

Pesticide Waste Minimization and Disposal.

6 p

Accurate and efficient waveforms for compact binaries on eccentric orbits

Compact binaries that emit gravitational waves in the sensitivity band of ground-based detectors can have non-negligible eccentricities just prior to merger, depending on the formation scenario. We develop a purely analytic, frequency-domain model for gravitational waves emitted by compact binaries on orbits with small eccentricity, which reduces to the quasi-circular post-Newtonian approximant TaylorF2 at zero eccentricity and to the post-circular approximation of Yunes et al. (2009) at small eccentricity. Our model uses a spectral approximation to the (post-Newtonian) Kepler problem to model the orbital phase as a function of frequency, accounting for eccentricity effects up to ${\cal{O}}(e^8)$ at each post-Newtonian order. Our approach accurately reproduces an alternative time-domain eccentric waveform model for eccentricities $e\in [0, 0.4]$ and binaries with total mass less than 12 solar masses. As an application, we evaluate the signal amplitude that eccentric binaries produce in different networks of existing and forthcoming gravitational waves detectors. Assuming a population of eccentric systems containing black holes and neutron stars that is uniformly distributed in co-moving volume, we estimate that second generation detectors like Advanced LIGO could detect approximately 0.1-10 events per year out to redshift $z\sim 0.2$, while an array of Einstein Telescope detectors could detect hundreds of events per year to redshift $z \sim 2.3$.Comment: 12 pages, 6 figures, 1 appendix. Submitted to Phys. Rev. D. v2: affiliations updated, one reference corrected. Accepted to Phys. Rev.