Scene simulation for passive IR systems

The development of large mosaic detector arrays will allow for the construction of staring long wave infrared (LWIR) sensors which can observe large fields of view instantaneously and continuously. In order to evaluate and exercise these new systems, it will be necessary to provide simulated scenes of many moving targets against an infrared clutter background. Researchers are currently developing a projector/screen system. This system is comprised of a mechanical scanner, a diffuse screen, and a miniature blackbody. A prototype of the mechanical scanner, which is comprised of four independently driven scanners, has been designed, fabricated, and evaluated under room and cryogenic vacuum conditions. A large diffuse screen has been constructed and tested for structural integrity under cryogenic/vacuum thermal cycling. Construction techniques have been developed for the fabrication of miniature high-temperature blackbody sources. Finally, a concept has been developed to use this miniature blackbody to produce a spectrally tailorable source

Geometric, aerodynamic, and kinematic characteristics of two twin keel parawings during deployment

Flight test data on geometric, aerodynamic, and kinematic characteristics of two twin keel parawings during deploymen

The impact of the warm outflow in the young (GPS) radio source & ULIRG PKS 1345+12 (4C 12.50)

(Abridged) We present new deep VLT/FORS optical spectra with intermediate resolution and large wavelength coverage of the GPS radio source and ULIRG PKS1345+12 (4C12.50; z=0.122), taken with the aim of investigating the impact of the nuclear activity on the circumnuclear ISM. PKS1345+12 is a powerful quasar and is also the best studied case of an emission line outflow in a ULIRG. Using the density sensitive transauroral emission lines [S II]4068,4076 and [O II]7318,7319,7330,7331, we pilot a new technique to accurately model the electron density for cases in which it is not possible to use the traditional diagnostic [S II]6716/6731, namely sources with highly broadened complex emission line profiles and/or high (Ne > 10^4 cm^-3) electron densities. We measure electron densities of Ne=2.94x10^3 cm^-3, Ne=1.47x10^4 cm^-3 and Ne=3.16x10^5 cm^-3 for the regions emitting the narrow, broad and very broad components respectively. We calculate a total mass outflow rate of 8 M_sun yr^-1. We estimate the total mass in the warm gas outflow is 8x10^5 M_sun. The total kinetic power in the warm outflow is 3.4x10^42 erg s^-1. We find that only a small fraction (0.13% of Lbol) of the available accretion power is driving the warm outflow, significantly less than currently required by the majority of quasar feedback models (~5-10\% of Lbol), but similar to recent findings by Hopkins et al. (2010) for a two-stage feedback model. The models also predict that AGN outflows will eventually remove the gas from the bulge of the host galaxy. The visible warm outflow in PKS1345+12 is not currently capable of doing so. However, it is entirely possible that much of the outflow is either obscured by a dense and dusty natal cocoon and/or in cooler or hotter phases of the ISM. This result is important not just for studies of young (GPS/CSS) radio sources, but for AGN in general.Comment: Accepted for publication in MNRAS. 11 pages, 4 figure

Gas outflows in radio galaxies

We present a summary of our recent results on gas outflows in radio galaxies. Fast outflows (up to 2000 km/s) have been detected both in ionized and neutral gas. The latter is particularly surprising as it shows that, despite the extremely energetic phenomena occurring near an AGN, some of the outflowing gas remains, or becomes again, neutral. These results are giving new and important insights on the physical conditions of the gaseous medium around an AGN.Comment: To appear in the proceedings of the IAU Symposium #217, Recycling Intergalactic and Interstellar Matter, eds. P.-A. Duc, J. Braine, and E. Brinks, 6 pages. The full paper with high resolution images can be downloaded from http://www.astron.nl/~morganti/Papers/outflows.ps.g

Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction

Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e′pω, at central Q² values of 1.60, 2.45  GeV², at W=2.21  GeV. The results of our pioneering −u≈−u_(min) study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q²=2.45  GeV², the observed dominance of σ_T over σ_L, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics

Impact of ¹⁶O(e,e′α)¹²C measurements on the ¹²C(α,γ)¹⁶O astrophysical reaction rate

The ¹²C(α,γ)¹⁶O reaction, an important component of stellar helium burning, has a key role in nuclear astrophysics. It has direct impact on the evolution and final state of massive stars and also influences the elemental abundances resulting from nucleosynthesis in such stars. Providing a reliable estimate for the energy dependence of this reaction at stellar helium burning temperatures has been a longstanding and important goal. In this work, we study the role of potential new measurements of the ¹⁶O(e,e′α)¹²C reaction in reducing the overall uncertainty. A multilevel R-matrix analysis is used to make extrapolations of the astrophysical S factor for the ¹²C(α,γ)¹⁶O reaction to the stellar energy of 300 keV. The statistical precision of the S-factor extrapolation is determined by performing multiple fits to existing E1 and E2 ground state capture data, including the impact of possible future measurements of the ¹⁶O(e,e′α)¹²C reaction. In particular, we consider a proposed MIT experiment that would make use of a high-intensity low-energy electron beam that impinges on a windowless oxygen gas target as a means to determine the total E1 and E2 cross sections for this reaction

Equivalence-based Security for Querying Encrypted Databases: Theory and Application to Privacy Policy Audits

Motivated by the problem of simultaneously preserving confidentiality and usability of data outsourced to third-party clouds, we present two different database encryption schemes that largely hide data but reveal enough information to support a wide-range of relational queries. We provide a security definition for database encryption that captures confidentiality based on a notion of equivalence of databases from the adversary's perspective. As a specific application, we adapt an existing algorithm for finding violations of privacy policies to run on logs encrypted under our schemes and observe low to moderate overheads.Comment: CCS 2015 paper technical report, in progres

Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction

Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e′pω, at central Q² values of 1.60, 2.45  GeV², at W=2.21  GeV. The results of our pioneering −u≈−u_(min) study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q²=2.45  GeV², the observed dominance of σ_T over σ_L, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics