Particle trajectory computer program for icing analysis of axisymmetric bodies

General aviation aircraft and helicopters exposed to an icing environment can accumulate ice resulting in a sharp increase in drag and reduction of maximum lift causing hazardous flight conditions. NASA Lewis Research Center (LeRC) is conducting a program to examine, with the aid of high-speed computer facilities, how the trajectories of particles contribute to the ice accumulation on airfoils and engine inlets. This study, as part of the NASA/LeRC research program, develops a computer program for the calculation of icing particle trajectories and impingement limits relative to axisymmetric bodies in the leeward-windward symmetry plane. The methodology employed in the current particle trajectory calculation is to integrate the governing equations of particle motion in a flow field computed by the Douglas axisymmetric potential flow program. The three-degrees-of-freedom (horizontal, vertical, and pitch) motion of the particle is considered. The particle is assumed to be acted upon by aerodynamic lift and drag forces, gravitational forces, and for nonspherical particles, aerodynamic moments. The particle momentum equation is integrated to determine the particle trajectory. Derivation of the governing equations and the method of their solution are described in Section 2.0. General features, as well as input/output instructions for the particle trajectory computer program, are described in Section 3.0. The details of the computer program are described in Section 4.0. Examples of the calculation of particle trajectories demonstrating application of the trajectory program to given axisymmetric inlet test cases are presented in Section 5.0. For the examples presented, the particles are treated as spherical water droplets. In Section 6.0, limitations of the program relative to excessive computer time and recommendations in this regard are discussed

Precision of diffuse 21-cm lensing

We study the limits of accuracy for weak lensing maps of dark matter using diffuse 21-cm radiation from the pre-reionization epoch using simulations. We improve on previous "optimal" quadratic lensing estimators by using shear and convergence instead of deflection angles. We find that non-Gaussianity provides a limit to the accuracy of weak lensing reconstruction, even if instrumental noise is reduced to zero. The best reconstruction result is equivalent to Gaussian sources with effectively independent cell of side length 2.0/h Mpc. Using a source full map from z=10-20, this limiting sensitivity allows mapping of dark matter at a Signal-to-Noise ratio (S/N) greater than 1 out to l < 6000, which is better than any other proposed technique for large area weak lensing mapping.Comment: 16 pages, 7 figures, submitted to MNRA

First Detection of Cosmic Structure in the 21-cm Intensity Field

We present the first statistically significant detection of cosmic structure using broadly distributed hydrogen radio emission. This is accomplished using a cross correlation with optical galaxies. Statistical noise levels of $20 \mu$K are achieved, unprecedented in this frequency band. This lends support to the idea that large volumes of the universe can be rapidly mapped without the need to resolve individual faint galaxies, enabling precise constraints to dark energy models. We discuss strategies for improved intensity mapping.Comment: 5 pages, 4 figures, submitted to MNRA

Introduction to the Special Issue on “Earth Observation FORMOSAT-5”

The National SPace Organization (NSPO) was founded in 1991 to pursue self-reliant space technology to nurture the domestic space industry and promote space science research in Taiwan. As an extension of the widely-accepted FORMOSAT-2 remote sensing satellite, NSPO is self-reliantly developing FORMOSAT-5 to continue its international earth observation image and space science research services. FORMOSAT-5 will offer state-of-the-art ionospheric space science data for geoscience research. It will also provide two-meter panchromatic and four-meter multi-spectrum images at various processing levels. Using the heritage and lessons-learned from the FORMOSAT-1/Ionospheric Plasma and Electrodynamics Instrument (IPEI), FORMOSAT-5/Advanced Ionospheric Probe (AIP) becomes an all-in-one plasma sensor with a sampling rate up to 8192 Hz to measure ionospheric plasma concentrations, velocities, temperatures, and ambient magnetic fields over a wide range of spatial scales. FORMOSAT-5’s global coverage capability, smart agility feature and pioneer use of a Complementary Metal-Oxide-Semiconductor (CMOS) sensor for commercial optical earth observation satellites (Chang et al. 2012a) will bring even broader research applications to the geoscience community. The 500-kg FORMOSAT-5 satellite, as shown in Fig. 1, will soon be launched into a two-day revisit Sun-synchronous orbit at 720 km altitude and 98.28° inclination

Sarcoma of the Larynx: Treatment Results and Literature Review

BackgroundSarcomas of the larynx are rare neoplasms that constitute less than 1% of laryngeal malignancies. A Medline search found no large series focusing on laryngeal sarcomas. We reviewed the cases of laryngeal sarcomas treated in our cancer center and compared our experiences and treatment results with those from other centers.MethodsA retrospective review of 10 patients with laryngeal sarcoma treated in our institute between 1980 and 2000 was done to identify tumor characteristics, therapeutic modalities, and treatment outcomes.ResultsThe patients showed a male predominance (9/10) and presented 8 types of pathology. Nine patients underwent surgery, including 2 total laryngectomy, 4 partial laryngectomy, and 3 endoscopic laser cordectomy. During a median follow-up of 92 months, the 5-year overall survival and disease-specific survival were 76% and 90%, respectively. Two patients developed recurrence, including 1 local recurrence and 1 distant metastasis.ConclusionSurgical intervention was the first choice in the treatment of laryngeal sarcomas. The prognosis is relatively good when compared with sarcoma originating from other anatomic sites

Interpreting The Unresolved Intensity Of Cosmologically Redshifted Line Radiation

Intensity mapping experiments survey the spectrum of diffuse line radiation rather than detect individual objects at high signal-to-noise ratio. Spectral maps of unresolved atomic and molecular line radiation contain three-dimensional information about the density and environments of emitting gas and efficiently probe cosmological volumes out to high redshift. Intensity mapping survey volumes also contain all other sources of radiation at the frequencies of interest. Continuum foregrounds are typically approximately 10(sup 2)-10(Sup 3) times brighter than the cosmological signal. The instrumental response to bright foregrounds will produce new spectral degrees of freedom that are not known in advance, nor necessarily spectrally smooth. The intrinsic spectra of fore-grounds may also not be well known in advance. We describe a general class of quadratic estimators to analyze data from single-dish intensity mapping experiments and determine contaminated spectral modes from the data themselves. The key attribute of foregrounds is not that they are spectrally smooth, but instead that they have fewer bright spectral degrees of freedom than the cosmological signal. Spurious correlations between the signal and foregrounds produce additional bias. Compensation for signal attenuation must estimate and correct this bias. A successful intensity mapping experiment will control instrumental systematics that spread variance into new modes, and it must observe a large enough volume that contaminant modes can be determined independently from the signal on scales of interest