Composite Structures using Asphalt Based Roofing Scrap Materials: EIERA -- Final Report

The uses of recycled materials in composites provide the potential for large cost savings and a solution to the ever-growing disposal problem. Shingles contain petroleum based binders and fillers, which used as a valuable resource in composite production. Composites offer inherent advantages over traditional materials in regard to corrosion resistance, design flexibility and extended service life. Use of scrap-roofing shingles as a core material in glass fiber reinforced composite materials offer potential low cost composite products such as sound barrier system, railroad ties and other building materials including blocks. In the present work, processes have been developed for shredding scrap roof shingles, for making shingle blocks, and for filling hollow composite tubes. Mechanical testing was performed to compare the performance of filled composite tubes to hollow tubes and oak wood beams. Filled tubes show improvement in ultimate flexural strength by preventing buckling and crushing. Tests were also conducted to evaluate the sound attenuation capability of recycled shingle walls. It was observed that the mean sound level at the backside of the wall, measured in decibels, was greatly reduced and shows potential use for recycled shingles in a sound barrier system. University of Missouri-Rolla has collaborated with Future Tek Inc. and Lemay Center for Composites Technology for successful completion of this project. The economic benefits are truly immense. This project will impact the community by diverting thousands of tons of shingles into usable products with a real economic impact

Magnetic field dependence of the internal quality factor and noise performance of lumped-element kinetic inductance detectors

We present a technique for increasing the internal quality factor of kinetic inductance detectors (KIDs) by nulling ambient magnetic fields with a properly applied magnetic field. The KIDs used in this study are made from thin-film aluminum, they are mounted inside a light-tight package made from bulk aluminum, and they are operated near $150 \, \mathrm{mK}$. Since the thin-film aluminum has a slightly elevated critical temperature ($T_\mathrm{c} = 1.4 \, \mathrm{K}$), it therefore transitions before the package ($T_\mathrm{c} = 1.2 \, \mathrm{K}$), which also serves as a magnetic shield. On cooldown, ambient magnetic fields as small as approximately $30 \, \mathrm{\mu T}$ can produce vortices in the thin-film aluminum as it transitions because the bulk aluminum package has not yet transitioned and therefore is not yet shielding. These vortices become trapped inside the aluminum package below $1.2 \, \mathrm{K}$ and ultimately produce low internal quality factors in the thin-film superconducting resonators. We show that by controlling the strength of the magnetic field present when the thin film transitions, we can control the internal quality factor of the resonators. We also compare the noise performance with and without vortices present, and find no evidence for excess noise beyond the increase in amplifier noise, which is expected with increasing loss.Comment: 5 pages, 4 figure

Access to Opportunity Project: Final Report

This project’s goal is to lift up promising approaches, suggest new strategies and encourage honest conversations that result in public policy solutions to income and racial segregation and poverty. The overarching question that motivates this work is: What are effective policies and strategies that promote access to high-opportunity amenities for low-income families? As a first step, the researchers surveyed efforts on the ground in the metropolitan areas encompassing Seattle, Washington; Portland, Oregon; and San Diego, California, to determine whether there were any candidates for deeper study. We selected these three metropolitan areas for several reasons. First, prior interaction revealed that attention had been given to this question and that parties in each had embarked on purposeful efforts to make progress. Second, they represent a diverse array of communities that vary in significant ways, including along key economic, demographic, and social dimensions, and in some regards are bellwethers for changes beginning to take place in many parts of the country. As a consequence, experiences and successes in these places could potentially be applied to a diverse set of other urban areas across the United States. The three regions are among the largest in the United States, with Seattle and Portland being the largest in their respective states and San Diego third in California (behind Los Angeles and the Bay Area). Despite their size, they differ in important ways that result in different social and political dynamics prevailing in each location. In considering access to opportunity, one must understand the opportunities that are available in order to tailor skill-building efforts and investments in “connective infrastructure,” such as mass transit and suburban affordable housing, so that they are maximally effective. From an economic perspective, the three regions are quite different, which means that the approaches observed across the regions will potentially vary in measurable ways. In each metropolitan area, we sought the counsel of key governmental, practitioner, academic, and philanthropic players. During the course of our initial visits to each region, we met with and interviewed almost 80 people—28 in Seattle, 26 in Portland, and 24 in San Diego. Through these conversations, we identified 27 projects—nine in each metropolitan area—as being promising examples of cases where lower-income families may have achieved increased access to high-opportunity amenities. Given time, available funding, and the presence of partners willing to support our research effort by providing access to program data and program participants, we chose three projects for examination: • The San Diego Housing Commission’s Achievement Academy • Seattle/King County’s A Regional Coalition for Housing (ARCH) • Humboldt Gardens in Northeast Portlan

Needed Research on the Englishes of Appalachia

Information about the 79th annual meeting of the Southeastern Conference on Linguistics (SECOL) organized by Jennifer Cramer at the University of Kentucky on April 2012 in Lexington, Kentucky. Topics discussed at the meeting includes current state of research studies on linguistic processes in Appalachia, traditional dialectological and ethnographic. The meeting also featured panel experts including Bridget L. Anderson, Michael Montgomery and Walt Wolfram

The Detector System for the Stratospheric Kinetic Inductance Polarimeter (SKIP)

The Stratospheric Kinetic Inductance Polarimeter (SKIP) is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background and Galactic dust emission by observing 1133 square degrees of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors (LEKID). The LEKIDs will be maintained at 100 mK with an adiabatic demagnetization refrigerator. The polarimeter operates in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcmin FWHM beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and rotated by a superconducting magnetic bearing. The observation program consists of at least two, five-day flights beginning with the 150 GHz observations.Comment: J Low Temp Phys DOI 10.1007/s10909-013-1014-3 The final publication is available at link.springer.co

A Titanium Nitride Absorber for Controlling Optical Crosstalk in Horn-Coupled Aluminum LEKID Arrays for Millimeter Wavelengths

We discuss the design and measured performance of a titanium nitride (TiN) mesh absorber we are developing for controlling optical crosstalk in horn-coupled lumped-element kinetic inductance detector arrays for millimeter-wavelengths. This absorber was added to the fused silica anti-reflection coating attached to previously-characterized, 20-element prototype arrays of LEKIDs fabricated from thin-film aluminum on silicon substrates. To test the TiN crosstalk absorber, we compared the measured response and noise properties of LEKID arrays with and without the TiN mesh. For this test, the LEKIDs were illuminated with an adjustable, incoherent electronic millimeter-wave source. Our measurements show that the optical crosstalk in the LEKID array with the TiN absorber is reduced by 66\% on average, so the approach is effective and a viable candidate for future kilo-pixel arrays.Comment: 7 pages, 5 figures, accepted for publication in the Journal of Low Temperature Physic

A LEKID-based CMB instrument design for large-scale observations in Greenland

We present the results of a feasibility study, which examined deployment of a ground-based millimeter-wave polarimeter, tailored for observing the cosmic microwave background (CMB), to Isi Station in Greenland. The instrument for this study is based on lumped-element kinetic inductance detectors (LEKIDs) and an F/2.4 catoptric, crossed-Dragone telescope with a 500 mm aperture. The telescope is mounted inside the receiver and cooled to $<\,4$ K by a closed-cycle $^4$He refrigerator to reduce background loading on the detectors. Linearly polarized signals from the sky are modulated with a metal-mesh half-wave plate that is rotated at the aperture stop of the telescope with a hollow-shaft motor based on a superconducting magnetic bearing. The modular detector array design includes at least 2300 LEKIDs, and it can be configured for spectral bands centered on 150~GHz or greater. Our study considered configurations for observing in spectral bands centered on 150, 210 and 267~GHz. The entire polarimeter is mounted on a commercial precision rotary air bearing, which allows fast azimuth scan speeds with negligible vibration and mechanical wear over time. A slip ring provides power to the instrument, enabling circular scans (360 degrees of continuous rotation). This mount, when combined with sky rotation and the latitude of the observation site, produces a hypotrochoid scan pattern, which yields excellent cross-linking and enables 34\% of the sky to be observed using a range of constant elevation scans. This scan pattern and sky coverage combined with the beam size (15~arcmin at 150~GHz) makes the instrument sensitive to $5 < \ell < 1000$ in the angular power spectra

Horn-Coupled, Commercially-Fabricated Aluminum Lumped-Element Kinetic Inductance Detectors for Millimeter Wavelengths

We discuss the design, fabrication, and testing of prototype horn-coupled, lumped-element kinetic inductance detectors (LEKIDs) designed for cosmic microwave background (CMB) studies. The LEKIDs are made from a thin aluminum film deposited on a silicon wafer and patterned using standard photolithographic techniques at STAR Cryoelectronics, a commercial device foundry. We fabricated twenty-element arrays, optimized for a spectral band centered on 150 GHz, to test the sensitivity and yield of the devices as well as the multiplexing scheme. We characterized the detectors in two configurations. First, the detectors were tested in a dark environment with the horn apertures covered, and second, the horn apertures were pointed towards a beam-filling cryogenic blackbody load. These tests show that the multiplexing scheme is robust and scalable, the yield across multiple LEKID arrays is 91%, and the noise-equivalent temperatures (NET) for a 4 K optical load are in the range 26\thinspace\pm6 \thinspace \mu \mbox{K} \sqrt{\mbox{s}}