High Speed Balancing Applied to the T700 Engine

The work performed under Contracts NAS3-23929 and NAS3-24633 is presented. MTI evaluated the feasibility of high-speed balancing for both the T700 power turbine rotor and the compressor rotor. Modifications were designed for the existing Corpus Christi Army Depot (CCAD) T53/T55 high-speed balancing system for balancing T700 power turbine rotors. Tests conducted under these contracts included a high-speed balancing evaluation for T700 power turbines in the Army/NASA drivetrain facility at MTI. The high-speed balancing tests demonstrated the reduction of vibration amplitudes at operating speed for both low-speed balanced and non-low-speed balanced T700 power turbines. In addition, vibration data from acceptance tests of T53, T55, and T700 engines were analyzed and a vibration diagnostic procedure developed

An imaging and spectroscopic study of the planetary nebulae in NGC 5128 (Centaurus A): Planetary nebulae catalogues

Imaging and spectroscopic observations of planetary nebulae (PNe) in the nearest large elliptical galaxy NGC 5128 (Centaurus A), were obtained to find more PNe and measure their radial velocities. NTT imaging was obtained in 15 fields in NGC 5128 over an area of about 1 square degree with EMMI using [O III] and off-band filters. Newly detected sources, combined with literature PNe, were used as input for VLT FLAMES multi-fibre spectroscopy in MEDUSA mode. Spectra of the 4600-5100A region were analysed and velocities measured based on emission lines of [O III]4959,5007A and often H-beta. The chief results are catalogues of 1118 PN candidates and 1267 spectroscopically confirmed PNe in NGC 5128. The catalogue of PN candidates contains 1060 PNe discovered with EMMI imaging and 58 from literature surveys. The spectroscopic PN catalogue has FLAMES radial velocity and emission line measurements for 1135 PNe, of which 486 are new. Another 132 PN radial velocities are available from the literature. For 629 PNe observed with FLAMES, H-beta was measured in addition to [O III]. Nine targets show double-lined or more complex profiles, and their possible origin is discussed. FLAMES spectra of 48 globular clusters were also targetted: 11 had emission lines detected (two with multiple components), but only 3 are PNe likely to belong to the host globular. The total of 1267 confirmed PNe in NGC 5128 with radial velocity measurements (1135 with small velocity errors) is the largest collection of individual kinematic probes in an early-type galaxy. This PN dataset, as well as the catalogue of PN candidates, are valuable resources for detailed investigation of the stellar population of NGC 5128. [Abridged]Comment: 19 pages, 11 figures. Accepted for publication in Astronomy and Astrophysics. Tables 7 - 11 available in electronic form at CDS. Replaced with a few typos fixe

First Detection of Mid-Infrared Variability from an Ultraluminous X-Ray Source Holmberg II X-1

We present mid-infrared (IR) light curves of the Ultraluminous X-ray Source (ULX) Holmberg II X-1 from observations taken between 2014 January 13 and 2017 January 5 with the \textit{Spitzer Space Telescope} at 3.6 and 4.5 $\mu$m in the \textit{Spitzer} Infrared Intensive Transients Survey (SPIRITS). The mid-IR light curves, which reveal the first detection of mid-IR variability from a ULX, is determined to arise primarily from dust emission rather than from a jet or an accretion disk outflow. We derived the evolution of the dust temperature ($T_\mathrm{d}\sim600 - 800$ K), IR luminosity ($L_\mathrm{IR}\sim3\times10^4$ $\mathrm{L}_\odot$), mass ($M_\mathrm{d}\sim1-3\times10^{-6}$ $\mathrm{M}_\odot$), and equilibrium temperature radius ($R_\mathrm{eq}\sim10-20$ AU). A comparison of X-1 with a sample spectroscopically identified massive stars in the Large Magellanic Cloud on a mid-IR color-magnitude diagram suggests that the mass donor in X-1 is a supergiant (sg) B[e]-star. The sgB[e]-interpretation is consistent with the derived dust properties and the presence of the [Fe II] ($\lambda=1.644$ $\mu$m) emission line revealed from previous near-IR studies of X-1. We attribute the mid-IR variability of X-1 to increased heating of dust located in a circumbinary torus. It is unclear what physical processes are responsible for the increased dust heating; however, it does not appear to be associated with the X-ray flux from the ULX given the constant X-ray luminosities provided by serendipitous, near-contemporaneous X-ray observations around the first mid-IR variability event in 2014. Our results highlight the importance of mid-IR observations of luminous X-ray sources traditionally studied at X-ray and radio wavelengths.Comment: 9 page, 4 figures, 1 table, Accepted to ApJ Letter

Synergistic relationships among remote-sensing and geophysical media: Geological and hydrological applications

The synergistic relationships among LANDSAT imagery, Skylab photographs, and aerial photographs were useful for establishing areas of near surface bedrock. Lineaments were located on LANDSAT imagery and aerial photographs during 1978 and near surface water tables were to be located during 1980. Both of these subjects can be identified by remote sensing methods more reliably than individual outcrops, which are small and occur in a wide variety of environments with a wide range of responses. Bedrock outcrops themselves could not be resolved by any of the data sources used, nor did any combination of data sources specifically identify rock at the ground surface. The data sources could not simply be combined mathematically to produce a visual image of probable areas of near surface bedrock. Outcrops and near surface bedrock had to be verified visually at the site. Despite these drawbacks, a procedure for locating areas of near surface bedrock within which actual surface outcrops may occur was developed

Complexity plots

In this paper, we present a novel visualization technique for assisting in observation and analysis of algorithmic\ud complexity. In comparison with conventional line graphs, this new technique is not sensitive to the units of\ud measurement, allowing multivariate data series of different physical qualities (e.g., time, space and energy) to be juxtaposed together conveniently and consistently. It supports multivariate visualization as well as uncertainty visualization. It enables users to focus on algorithm categorization by complexity classes, while reducing visual impact caused by constants and algorithmic components that are insignificant to complexity analysis. It provides an effective means for observing the algorithmic complexity of programs with a mixture of algorithms and blackbox software through visualization. Through two case studies, we demonstrate the effectiveness of complexity plots in complexity analysis in research, education and application

Advancing imaging technologies for patients with spinal pain : with a focus on whiplash injury

Background: Radiological observations of soft-tissue changes that may relate to clinical symptoms in patients with traumatic and non-traumatic spinal disorders are highly controversial. Studies are often of poor quality and findings are inconsistent. A plethora of evidence suggests some pathoanatomical findings from traditional imaging applications are common in asymptomatic participants across the life span, which further questions the diagnostic, prognostic, and theranostic value of traditional imaging. Although we do not dispute the limited evidence for the clinical importance of most imaging findings, we contend that the disparate findings across studies may in part be due to limitations in the approaches used in assessment and analysis of imaging findings. Purpose: This clinical commentary aimed to (1) briefly detail available imaging guidelines, (2) detail research-based evidence around the clinical use of findings from advanced, but available, imaging applications (eg, fat and water magnetic resonance imaging and magnetization transfer imaging), and (3) introduce how evolving imaging technologies may improve our mechanistic understanding of pain and disability, leading to improved treatments and outcomes. Study Design/Setting: A non-systematic review of the literature is carried out. Methods: A narrative summary (including studies from the authors' own work in whiplash injuries) of the available literature is provided. Results: An emerging body of evidence suggests that the combination of existing imaging sequences or the use of developing imaging technologies in tandem with a good clinical assessment of modifiable risk factors may provide important diagnostic information toward the exploration and development of more informed and effective treatment options for some patients with traumatic neck pain. Conclusions: Advancing imaging technologies may help to explain the seemingly disconnected spectrum of biopsychosocial signs and symptoms of traumatic neck pain

PCA of PCA: Principal Component Analysis of Partial Covering Absorption in NGC 1365

We analyse 400 ks of XMM-Newton data on the active galactic nucleus NGC 1365 using principal component analysis (PCA) to identify model independent spectral components. We find two significant components and demonstrate that they are qualitatively different from those found in MCG?6-30-15 using the same method. As the variability in NGC 1365 is known to be due to changes in the parameters of a partial covering neutral absorber, this shows that the same mechanism cannot be the driver of variability in MCG-6-30-15. By examining intervals where the spectrum shows relatively low absorption we separate the effects of intrinsic source variability, including signatures of relativistic reflection, from variations in the intervening absorption. We simulate the principal components produced by different physical variations, and show that PCA provides a clear distinction between absorption and reflection as the drivers of variability in AGN spectra. The simulations are shown to reproduce the PCA spectra of both NGC 1365 and MCG-6-30-15, and further demonstrate that the dominant cause of spectral variability in these two sources requires a qualitatively different mechanism.Comment: 8 pages, 10 figures. Accepted for publication in MNRA

Broad Iron Emission from Gravitationally Lensed Quasars Observed by Chandra

Recent work has demonstrated the potential of gravitationally lensed quasars to extend measurements of black hole spin out to high-redshift with the current generation of X-ray observatories. Here we present an analysis of a large sample of 27 lensed quasars in the redshift range 1.0<z<4.5 observed with Chandra, utilizing over 1.6 Ms of total observing time, focusing on the rest-frame iron K emission from these sources. Although the X-ray signal-to-noise (S/N) currently available does not permit the detection of iron emission from the inner accretion disk in individual cases in our sample, we find significant structure in the stacked residuals. In addition to the narrow core, seen almost ubiquitously in local AGN, we find evidence for an additional underlying broad component from the inner accretion disk, with a clear red wing to the emission profile. Based on simulations, we find the detection of this broader component to be significant at greater than the 3-sigma level. This implies that iron emission from the inner disk is relatively common in the population of lensed quasars, and in turn further demonstrates that, with additional observations, this population represents an opportunity to significantly extend the sample of AGN spin measurements out to high-redshift.Comment: 5 pages, 2 figures, accepted for publication in Ap

Baseline design of the filters for the LAD detector on board LOFT

The Large Observatory for X-ray Timing (LOFT) was one of the M3 missions selected for the phase A study in the ESA's Cosmic Vision program. LOFT is designed to perform high-time-resolution X-ray observations of black holes and neutron stars. The main instrument on the LOFT payload is the Large Area Detector (LAD), a collimated experiment with a nominal effective area of ~10 m 2 @ 8 keV, and a spectral resolution of ~240 eV in the energy band 2-30 keV. These performances are achieved covering a large collecting area with more than 2000 large-area Silicon Drift Detectors (SDDs) each one coupled to a collimator based on lead-glass micro-channel plates. In order to reduce the thermal load onto the detectors, which are open to Sky, and to protect them from out of band radiation, optical-thermal filter will be mounted in front of the SDDs. Different options have been considered for the LAD filters for best compromise between high quantum efficiency and high mechanical robustness. We present the baseline design of the optical-thermal filters, show the nominal performances, and present preliminary test results performed during the phase A study.Comment: Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 91446