12,008 research outputs found
War on the Wards: The collapse of health care infrastructure resulting from violent conflict
Introduction: While utilizing satellite images to verify reports of hospital damage resulting from armed conflict allows for remote assessment, the use of private satellites to gain access to images prohibits widespread use. The questions this study sought to answer were: Is it possible to replicate the findings of previous reports of hospital damage that used the services of private satellite imagery using open source software, such as Google Earth? What variations exist among the different sites where damage to hospitals is visible, and what gradation is possible? Is this methodology applicable to other examples of armed conflict?
Methods: Using the map of bombed Syrian hospitals published and maintained by Physicians for Human Rights, hospitals were selected according to their location and the time period of the attack. These coordinates were entered into Google maps and once the attack was verified, a grade of damage was assigned. This methodology was then applied to reports of similar attacks in Iraq.
Results: While much information can be gleaned from open source data such as Google Earth, the level of detail in satellite images is lower and coordinates data is less specific. [Further results pending.]
Conclusion: There is room for the use of open source satellite technology to track and grade the damage done to health care infrastructure during armed conflict. [More conclusions pending.
Large inductive dimension of the Smirnov remainder
The purpose of this paper is to investigate the large inductive dimension of
the remainder of the Smirnov compactification of the n-dimensional Euclidean
space with the usual metric, and give an application of it.Comment: 8 pages, accepted for publication in Houston Journal of Mathematic
An assessment of the risk arising from electrical effects associated with carbon fibers released from commercial aircraft fires
The risks associated with electrical effects arising from carbon fibers released from commercial aviation aircraft fires were estimated for 1993. The expected annual losses were estimated to be about 100,000 (1977 dollars) in 1993 were established to be about one in ten thousand
Radius of Curvature Measurement of Large Optics Using Interferometry and Laser Tracker
The determination of radius of curvature (ROC) of optics typically uses either a phase measuring interferometer on an adjustable stage to determine the position of the ROC and the optics surface under test. Alternatively, a spherometer or a profilometer are used for this measurement. The difficulty of this approach is that for large optics, translation of the interferometer or optic under test is problematic because of the distance of translation required and the mass of the optic. Profilometry and spherometry are alternative techniques that can work, but require a profilometer or a measurement of subapertures of the optic. The proposed approach allows a measurement of the optic figure simultaneous with the full aperture radius of curvature
Enhanced-Adhesion Multi-Walled Carbon Nanotubes on Titanium Substrates for Stray Light Control
Carbon nanotubes previously grown on silicon have extremely low reflectance, making them a good candidate for stray light suppression. Silicon, however, is not a good structural material for stray light components such as tubes, stops, and baffles. Titanium is a good structural material and can tolerate the 700 C nanotube growth process. The ability to grow carbon nanotubes on a titanium substrate that are ten times blacker than the current NASA state-of-the-art paints in the visible to near infrared spectra has been achieved. This innovation will allow significant improvement of stray light performance in scientific instruments or any other optical system. This innovation is a refinement of the utilization of multiwalled carbon nano tubes for stray light suppression in spaceflight instruments. The innovation is a process to make the surface darker and improve the adhesion to the substrate, improving robustness for spaceflight use. Bright objects such as clouds or ice scatter light off of instrument structures and components and make it difficult to see dim objects in Earth observations. A darker material to suppress this stray light has multiple benefits to these observations, including enabling scientific observations not currently possible, increasing observational efficiencies in high-contrast scenes, and simplifying instruments and lowering their cost by utilizing fewer stray light components and achieving equivalent performance. The prior art was to use commercially available black paint, which resulted in approximately 4% of the light being reflected (hemispherical reflectance or total integrated scatter, or TIS). Use of multiwalled carbon nanotubes on titanium components such as baffles, entrance aperture, tubes, and stops, can decrease this scattered light by a factor of ten per bounce over the 200-nm to 2,500-nm wavelength range. This can improve system stray light performance by orders of magnitude. The purpose of the innovation is to provide an enhanced stray light control capability by making a blacker surface treatment for typical stray light control components. Since baffles, stops, and tubes used in scientific observations often undergo loads such as vibration, it was critical to develop this surface treatment on structural materials. The innovation is to optimize the carbon nanotube growth for titanium, which is a strong, lightweight structural material suitable for spaceflight use. The titanium substrate carbon nanotubes are more robust than those grown on silicon and allow for easier utilization. They are darker than current surface treatments over larger angles and larger wavelength range. The primary advantage of titanium substrate is that it is a good structural material, and not as brittle as silicon
Graphite Composite Panel Polishing Fixture
The use of high-strength, lightweight composites for the fixture is the novel feature of this innovation. The main advantage is the light weight and high stiffness-to-mass ratio relative to aluminum. Meter-class optics require support during the grinding/polishing process with large tools. The use of aluminum as a polishing fixture is standard, with pitch providing a compliant layer to allow support without deformation. Unfortunately, with meter-scale optics, a meter-scale fixture weighs over 120 lb (.55 kg) and may distort the optics being fabricated by loading the mirror and/or tool used in fabrication. The use of composite structures that are lightweight yet stiff allows standard techniques to be used while providing for a decrease in fixture weight by almost 70 percent. Mounts classically used to support large mirrors during fabrication are especially heavy and difficult to handle. The mount must be especially stiff to avoid deformation during the optical fabrication process, where a very large and heavy lap often can distort the mount and optic being fabricated. If the optic is placed on top of the lapping tool, the weight of the optic and the fixture can distort the lap. Fixtures to support the mirror during fabrication are often very large plates of aluminum, often 2 in. (.5 cm) or more in thickness and weight upwards of 150 lb (68 kg). With the addition of a backing material such as pitch and the mirror itself, the assembly can often weigh over 250 lb (.113 kg) for a meter-class optic. This innovation is the use of a lightweight graphite panel with an aluminum honeycomb core for use as the polishing fixture. These materials have been used in the aerospace industry as structural members due to their light weight and high stiffness. The grinding polishing fixture consists of the graphite composite panel, fittings, and fixtures to allow interface to the polishing machine, and introduction of pitch buttons to support the optic under fabrication. In its operation, the grinding polishing fixture acts as a reaction structure to the polishing tool. It must be stiff enough to avoid imparting a distorted shape to the optic under fabrication and light enough to avoid self-deflection. The fixture must also withstand significant tangential loads from the polishing machine during operations
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Search for supersymmetry and leptoquark states at FNAL
Searches have been made for first generation scalar and vector leptoquarks by the D0 collaboration and for second generation scalar leptoquarks by the CDF collaboration. Lower leptoquark mass limits were set. A search for squarks and gluinos, predicted by Supersymmetric models, was made by D0 in the three or more jets plus missing Et channel. The number of events observed was consistent with background. Squark and gluino mass limits were set
Pupil Alignment Measuring Technique and Alignment Reference for Instruments or Optical Systems
A technique was created to measure the pupil alignment of instruments in situ by measuring calibrated pupil alignment references (PARs) in instruments. The PAR can also be measured using an alignment telescope or an imaging system. PAR allows the verification of the science instrument (SI) pupil alignment at the integrated science instrument module (ISIM) level of assembly at ambient and cryogenic operating temperature. This will allow verification of the ISIM+SI alignment, and provide feedback to realign the SI if necessary
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