10,228 research outputs found
Automobiles - Injuries from Operation or Use of Highway - Whether It Is Possible to Obtain Substituted Service upon the Personal Representative of a Deceased Non-Resident Automobile Owner under a Statute Providing for Such Service upon a Non-Resident Owner or Operator
Shaped Pupil Lyot Coronagraphs: High-Contrast Solutions for Restricted Focal Planes
Coronagraphs of the apodized pupil and shaped pupil varieties use the
Fraunhofer diffraction properties of amplitude masks to create regions of high
contrast in the vicinity of a target star. Here we present a hybrid coronagraph
architecture in which a binary, hard-edged shaped pupil mask replaces the gray,
smooth apodizer of the apodized pupil Lyot coronagraph (APLC). For any contrast
and bandwidth goal in this configuration, as long as the prescribed region of
contrast is restricted to a finite area in the image, a shaped pupil is the
apodizer with the highest transmission. We relate the starlight cancellation
mechanism to that of the conventional APLC. We introduce a new class of
solutions in which the amplitude profile of the Lyot stop, instead of being
fixed as a padded replica of the telescope aperture, is jointly optimized with
the apodizer. Finally, we describe shaped pupil Lyot coronagraph (SPLC) designs
for the baseline architecture of the Wide-Field Infrared Survey
Telescope-Astrophysics Focused Telescope Assets (WFIRST-AFTA) coronagraph.
These SPLCs help to enable two scientific objectives of the WFIRST-AFTA
mission: (1) broadband spectroscopy to characterize exoplanet atmospheres in
reflected starlight and (2) debris disk imaging.Comment: 41 pages, 15 figures; published in the JATIS special section on
WFIRST-AFTA coronagraph
On the design and simulation of an airlift loop bioreactor with microbubble generation by fluidic oscillation
Microbubble generation by a novel fluidic oscillator driven approach is analyzed, with a view to identifying the key design elements and their differences from standard approaches to airlift loop bioreactor design. The microbubble generation mechanism has been shown to achieve high mass transfer rates by the decrease of the bubble diameter, by hydrodynamic stabilization that avoids coalescence increasing the bubble diameter, and by longer residence times offsetting slower convection. The fluidic oscillator approach also decreases the friction losses in pipe networks and in nozzles/diffusers due to boundary layer disruption, so there is actually an energetic consumption savings in using this approach over steady flow. These dual advantages make the microbubble generation approach a promising component of a novel airlift loop bioreactor whose design is presented here. The equipment, control system for flow and temperature, and the optimization of the nozzle bank for the gas distribution system are presented. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V All rights reserved
Self-Regulation in a Web-Based Course: A Case Study
Little is known about how successful students in Web-based courses self-regulate their learning. This descriptive case study used a social cognitive model of self-regulated learning (SRL) to investigate how six graduate students used and adapted traditional SRL strategies to complete tasks and cope with challenges in a Web-based technology course; it also explored motivational and environmental influences on strategy use. Primary data sources were three transcribed interviews with each of the students over the course of the semester, a transcribed interview with the course instructor, and the students’ reflective journals. Archived course documents, including transcripts of threaded discussions and student Web pages, were secondary data sources. Content analysis of the data indicated that these students used many traditional SRL strategies, but they also adapted planning, organization, environmental structuring, help seeking, monitoring, record keeping, and self-reflection strategies in ways that were unique to the Web-based learning environment. The data also suggested that important motivational influences on SRL strategy use—self-efficacy, goal orientation, interest, and attributions—were shaped largely by student successes in managing the technical and social environment of the course. Important environmental influences on SRL strategy use included instructor support, peer support, and course design. Implications for online course instructors and designers, and suggestions for future research are offered
Ray-based calculations of backscatter in laser fusion targets
A 1D, steady-state model for Brillouin and Raman backscatter from an
inhomogeneous plasma is presented. The daughter plasma waves are treated in the
strong damping limit, and have amplitudes given by the (linear) kinetic
response to the ponderomotive drive. Pump depletion, inverse-bremsstrahlung
damping, bremsstrahlung emission, Thomson scattering off density fluctuations,
and whole-beam focusing are included. The numerical code DEPLETE, which
implements this model, is described. The model is compared with traditional
linear gain calculations, as well as "plane-wave" simulations with the paraxial
propagation code pF3D. Comparisons with Brillouin-scattering experiments at the
OMEGA Laser Facility [T. R. Boehly et al., Opt. Commun. 133, p. 495 (1997)]
show that laser speckles greatly enhance the reflectivity over the DEPLETE
results. An approximate upper bound on this enhancement, motivated by phase
conjugation, is given by doubling the DEPLETE coupling coefficient. Analysis
with DEPLETE of an ignition design for the National Ignition Facility (NIF) [J.
A. Paisner, E. M. Campbell, and W. J. Hogan, Fusion Technol. 26, p. 755
(1994)], with a peak radiation temperature of 285 eV, shows encouragingly low
reflectivity. Re-absorption of Raman light is seen to be significant in this
design.Comment: 16 pages, 19 figure
Building a Freshwater Bacterial Flora Database for Remote Sensing Applications
The identification and classification of microbial flora in bodies of fresh water has the potential of enhancing our understanding of this ecosystem and improving water management and bioremediation. This effort may be facilitated by the use of remote sensing technologies. For the last 3 years our undergraduate students have collected water samples in the Lake Ontario Rochester Embayment and Irondequoit Bay with the goal of constructing a database of bacterial species and water parameters (e.g. organic matter and chlorophyl content). Such a database is necessary to establish potential correlations between the presence of certain bacterial species and water parameters that can be measured using satellite imagery collected by the Landsat 8 OLI and TIRS sensors. In the past we reported initial efforts at mapping the distribution of bacterial species using 16S rRNA. Here we present our results for the summer of 2015 and present a compounded analysis of 3 consecutive summers. Of approximately 450 bacterial isolates, we have cultured and identified more than 40 different species spanning over 20 genera. Several fish and human pathogens were identified, and antibiotic-resistance profiles determined. Year to year variation of the flora’s composition at individual locations has emerged as the main challenge in establishing reproducible patterns that may be linked to satellite measurements
Microbial Sampling of Major Bodies of Water in Rochester, NY
Public health concerns from wastewater treatment and agricultural runoff are an issue locally in Rochester, NewYork. In fact, many closings of Ontario Beach have been attributed to pollution or the threat of microbial contamination. Antibiotic resistance is a major issue that has become more prevalent in society, antibiotic resistant human pathogenic bacteria can overcome normal types of medicinal therapy, which cannot only lead to increased mortality but also increases in illness and cost of care. Additionally, antibiotic resistant plant pathogens can impact agriculture. In this study, bacterial species from the Lake Ontario embayment collected over the past three years were analyzed. Bacteria that were known to be human or plant pathogens were selected to evaluate for resistance to commonly used antibiotics using the Kirby Bauer disk diffusion assay. A few species exhibited resistance, preliminary results will be shown
Designing novel applications for emerging multimedia technology
Current R&D in media technologies such as Multimedia, Semantic Web and Sensor Web technologies are advancing in a fierce rate and will sure to become part of our important regular items in a 'conventional' technology inventory in near future. While the R&D nature of these technologies means their accuracy, reliability and robustness are not sufficient enough to be used in real world yet, we want to envision now the near-future where these technologies will have matured and used in real applications in order to explore and start shaping many possible new ways these novel technologies could be utilised.
In this talk, some of this effort in designing novel applications that incorporate various media technologies as their backend will be presented. Examples include novel scenarios of LifeLogging application that incorporate automatic structuring of millions of photos passively captured from a SenseCam (wearable digital camera that automatically takes photos triggered by environmental sensors) and an interactive TV application incorporating a number of multimedia tools yet extremely simple and easy to use with a remote control in a lean-back position. The talk will conclude with remarks on how the design of novel applications that have no precedence or existing user base should require somewhat different approach from those suggested and practiced in conventional usability engineering methodology
- …