456 research outputs found
Analysis of Photogrammetry Data from ISIM Mockup, June 1, 2007
During ground testing of the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST), the ISIM Optics group plans to use a Photogrammetry Measurement System for cryogenic calibration of specific target points on the ISIM composite structure and Science Instrument optical benches and other GSE equipment. This testing will occur in the Space Environmental Systems (SES) chamber at Goddard Space Flight Center. Close range photogrammetry is a 3 dimensional metrology system using triangulation to locate custom targets in 3 coordinates via a collection of digital photographs taken from various locations and orientations. These photos are connected using coded targets, special targets that are recognized by the software and can thus correlate the images to provide a 3 dimensional map of the targets, and scaled via well calibrated scale bars. Photogrammetry solves for the camera location and coordinates of the targets simultaneously through the bundling procedure contained in the V-STARS software
Analysis of Photogrammetry Data from ISIM Mockup
During ground testing of the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST), the ISIM Optics group plans to use a Photogrammetry Measurement System for cryogenic calibration of specific target points on the ISIM composite structure and Science Instrument optical benches and other GSE equipment. This testing will occur in the Space Environmental Systems (SES) chamber at Goddard Space Flight Center. Close range photogrammetry is a 3 dimensional metrology system using triangulation to locate custom targets in 3 coordinates via a collection of digital photographs taken from various locations and orientations. These photos are connected using coded targets, special targets that are recognized by the software and can thus correlate the images to provide a 3 dimensional map of the targets, and scaled via well calibrated scale bars. Photogrammetry solves for the camera location and coordinates of the targets simultaneously through the bundling procedure contained in the V-STARS software, proprietary software owned by Geodetic Systems Inc. The primary objectives of the metrology performed on the ISIM mock-up were (1) to quantify the accuracy of the INCA3 photogrammetry camera on a representative full scale version of the ISIM structure at ambient temperature by comparing the measurements obtained with this camera to measurements using the Leica laser tracker system and (2), empirically determine the smallest increment of target position movement that can be resolved by the PG camera in the test setup, i.e., precision, or resolution. In addition, the geometrical details of the test setup defined during the mockup testing, such as target locations and camera positions, will contribute to the final design of the photogrammetry system to be used on the ISIM Flight Structure
Enabling Greater Access to Home Meal Delivery
Non-profit organizations like the Meals on Wheels (MOW) association of America prepare and deliver meals, typically daily, to approximately one million homebound citizens in the United States alone. However, many MOW agencies are facing a steadily increasing number of clients requesting meal service without an increase in resources (either financial or human). One strategy for accommodating these requests is to deliver multiple (frozen) meals at a time and thus make fewer delivers. However, many of the stakeholders (funders, volunteers, meal recipients) value the relationships that are developed by having a client receive daily deliveries from the same volunteer. Further, meal recipients may be concerned with the quality of the food delivered through a frozen meal. In this paper, we develop a method for introducing consolidation into home meal delivery while minimizing operational disruptions and maintaining client satisfaction. With an extensive computational study, the savings associated with various levels and types of disruptions are detailed
Planning Strategies for Home Health Care Delivery
In home health care, continuity of care, wherein a patient is always visited by the same nurse, can be just as important as cost, as it is closely correlated to quality of care. While a patient typically receives care for two to three months, such that assigning a nurse to a patient impacts operations for lengthy periods of time, previous research focusing on continuity of care uses planning horizons that are often a week or shorter. This paper computationally demonstrates that considering a long planning horizon in this setting has significant potential for savings. Initially, a deterministic setting is considered, with all patient requests during the planning horizon known a priori, and the routing cost of planning for two to three months is compared with the cost when planning is done on a weekly basis. With inherent uncertainty in planning for such a long time horizon, a methodology is presented that anticipates future patient requests that are unknown at the time of planning. Computational evidence shows that its use is superior to planning on a weekly basis under uncertainty
Spatially Resolved Chandra HETG Spectroscopy of the NLR Ionization Cone in NGC 1068
We present initial results from a new 440-ks Chandra HETG GTO observation of
the canonical Seyfert 2 galaxy NGC 1068. The proximity of NGC 1068, together
with Chandra's superb spatial and spectral resolution, allow an unprecedented
view of its nucleus and circumnuclear NLR. We perform the first spatially
resolved high-resolution X-ray spectroscopy of the `ionization cone' in any
AGN, and use the sensitive line diagnostics offered by the HETG to measure the
ionization state, density, and temperature at discrete points along the ionized
NLR. We argue that the NLR takes the form of outflowing photoionized gas,
rather than gas that has been collisionally ionized by the small-scale radio
jet in NGC 1068. We investigate evidence for any velocity gradients in the
outflow, and describe our next steps in modeling the spatially resolved spectra
as a function of distance from the nucleus.Comment: 5 pages, 2 figures, 1 video. To appear in refereed Proceedings of
"X-ray Astronomy 2009: Present Status, Multi-Wavelength Approach and Future
Perspectives", Bologna, Italy, September 7-11, 2009, AIP, eds. A. Comastri,
M. Cappi, and L. Angelin
Quenching of the radio jet during the X-ray high state of GX 339-4
We have observed the black hole candidate X-ray binary GX 339-4 at radio
wavelengths before, during and after the 1998 high/soft X-ray state transition.
We find that the radio emission from the system is strongly correlated with the
hard X-ray emission and is reduced by a factor > 25 during the high/soft state
compared to the more usual low/hard state. At the points of state transition we
note brief periods of unusually optically-thin radio emission which may
correspond to discrete ejection events. We propose that in the low/hard state
black hole X-ray binaries produce a quasi-continuous outflow, in the high/soft
state this outflow is suppressed, and that state transitions often result in
one or more discrete ejection events. Future models for low/hard states, such
as ADAF/ADIOS solutions, need to take into account strong outflow of
relativistic electrons from the system. We propose that the inferred
Comptonising corona and the base of the jet-like outflow are the same thing,
based upon the strong correlation between radio and hard X-ray emission in GX
339-4 and other X-ray binaries, and the similarity in inferred location and
composition of these two components.Comment: Accepted for publication in ApJ Letter
Surgical smoke and ultrafine particles
© 2008 Brüske-Hohlfeld et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
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Simple method for sub-diffraction resolution imaging of cellular structures on standard confocal microscopes by three-photon absorption of quantum dots
This study describes a simple technique that improves a recently developed 3D sub-diffraction imaging method based on three-photon absorption of commercially available quantum dots. The method combines imaging of biological samples via tri-exciton generation in quantum dots with deconvolution and spectral multiplexing, resulting in a novel approach for multi-color imaging of even thick biological samples at a 1.4 to 1.9-fold better spatial resolution. This approach is realized on a conventional confocal microscope equipped with standard continuous-wave lasers. We demonstrate the potential of multi-color tri-exciton imaging of quantum dots combined with deconvolution on viral vesicles in lentivirally transduced cells as well as intermediate filaments in three-dimensional clusters of mouse-derived neural stem cells (neurospheres) and dense microtubuli arrays in myotubes formed by stacks of differentiated C2C12 myoblasts
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