The Host Galaxy and Central Engine of the Dwarf AGN POX 52

We present new multi-wavelength observations of the dwarf Seyfert 1 galaxy POX 52 in order to investigate the properties of the host galaxy and the active nucleus, and to examine the mass of its black hole, previously estimated to be ~ 10^5 M_sun. Hubble Space Telescope ACS/HRC images show that the host galaxy has a dwarf elliptical morphology (M_I = -18.4 mag, Sersic index n = 4.3) with no detected disk component or spiral structure, confirming previous results from ground-based imaging. X-ray observations from both Chandra and XMM show strong (factor of 2) variability over timescales as short as 500 s, as well as a dramatic decrease in the absorbing column density over a 9 month period. We attribute this change to a partial covering absorber, with a 94% covering fraction and N_H = 58^{+8.4}_{-9.2} * 10^21 cm^-2, that moved out of the line of sight in between the XMM and Chandra observations. Combining these data with observations from the VLA, Spitzer, and archival data from 2MASS and GALEX, we examine the spectral energy distribution (SED) of the active nucleus. Its shape is broadly similar to typical radio-quiet quasar SEDs, despite the very low bolometric luminosity of L_bol = 1.3 * 10^43 ergs/s. Finally, we compare black hole mass estimators including methods based on X-ray variability, and optical scaling relations using the broad H-beta line width and AGN continuum luminosity, finding a range of black hole mass from all methods to be M_bh = (2.2-4.2) * 10^5 M_sun, with an Eddington ratio of L_bol/L_edd = 0.2-0.5.Comment: 19 pages, 16 figures, accepted for publication in Ap

Field Validation of Multi-Species Laboratory Test Systems for Estuarine Benthic Communities

The aim of this project was to evaluate the validity of using multi-species laboratory systems to assess the response of eatuarine benthic communities to an introduced stress. Over a 5- year period experiments in Apalachicola Bay, Florida, and the York River, Virginia, sought to (1) develop criteria for microcosm tests for evaluating the capacity of microcosms to model natural communities in the presence and absence of a pollution-induced stress, and (2) assess the validity of extrapolating test results from one location to another. Procedures for constructing, maintaining and sampling microcosms were tested and refined over the study period. A large number of laboratory and field tests were conducted synoptically over this period, including experiments in which microcosms and field sites were dosed with toxicants (mixed hydrocarbons in some and pentachlorophenol in others). We have investigated various methodologies for analysing and interpreting data derived from microcosm tests

Micro-scale Artificial Weave Generation Capabilities for Thermal Protection System Material Modeling

Thermal Protection System (TPS) modeling requires accurate representation and prediction of the thermomechanical behavior of ablative materials. State-of-the-art TPS materials such as Phenolic Impregnated Carbon Ablator (PICA) have a proven flight record and demonstrate exceptional capabilities for handling extreme aerothermal heating conditions. The constant push for lightweight materials that are flexible in their design and performance, and hence allow for a wide range of mission profiles, has led NASA over the past years to develop its Heatshield for Extreme Entry Environment Technology (HEEET). HEEET is based primarily on a dual layer woven carbon fiber architecture and the technology has successfully been tested in arc-jet facilities. These recent developments have sparked interest in the accurate micro-scale modeling of composite weave architectures, to predict the structural response of macro-scale heatshields upon atmospheric entry. This effort can be extended to incorporate in-depth failure mechanics analyses as a result of local thermal gradients or high-velocity particle impact

Annual Progress Report, Study of Dynamic Rigidity of Marine Sediments

The report is divided into two tasks with each task summary being prepared by the principal investigators of that task. Task 1 includes a study of the dynamic rigidity, acoustic, and other engineering properties of marine sediments. Task 2 covers a study of upper ocean turbulence as related to acoustic measurements. (Author)http://archive.org/details/studyofdynamicri00and

Waveguiding and photoluminescence in Er³⁺-doped Ta₂O₅ planar waveguides

The optimization of erbium-doped Ta2O5 thin film waveguides deposited by magnetron sputtering onto thermally oxidized silicon wafer is described. Optical constants of the film were determined by ellipsometry. For the slab waveguides, background losses below 0.4dB/cm at 633nm have been obtained before post-annealing. The samples, when pumped at 980nm yielded abroad photoluminescence spectrum (FWHM ~50 nm) centred at 1534nm, corresponding to 4 I 13/2 to the 4 I 15/2 transition of Er3+ ion. The samples were annealed up to 600 °C and both photoluminescence power and fluorescence lifetime increase with post-annealing temperature and a fluorescence lifetime of 2.4ms was achieved, yielding promising results for compact waveguide amplifier

Risk Indicators for Periodontitis in US Adults: NHANES 2009 to 2012

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142205/1/jper1174.pd