Thermal Structures Technology Development for Reusable Launch Vehicle Cryogenic Propellant Tanks

Analytical and experimental studies conducted at the NASA, Langley Research Center (LaRC) for investigating integrated cryogenic propellant tank systems for a reusable launch vehicle (RLV) are described. The cryogenic tanks are investigated as an integrated tank system. An integrated tank system includes the tank wall, cryogenic insulation, thermal protection system (TPS) attachment sub-structure, and TPS. Analysis codes are used to size the thicknesses of cryogenic insulation and TPS insulation for thermal loads, and to predict tank buckling strengths at various ring frame spacings. The unique test facilities developed for the testing of cryogenic tank components are described. Testing at cryogenic and high-temperatures verifies the integrity of materials, design concepts, manufacturing processes, and thermal/structural analyses. Test specimens ranging from the element level to the subcomponent level are subjected to projected vehicle operational mechanical loads and temperatures. The analytical and experimental studies described in this paper provide a portion of the basic information required for the development of light-weight reusable cryogenic propellant tanks

Do persistent organic pollutants stimulate cyanobacterial blooms?

The use of persistent organic pollutants (POPs), such as herbicides, pesticides, pharmaceutical and personal care products (PCPPs), and polycyclic aromatic hydrocarbons (PAHs), has more than doubled since 1950. POPs find their way into aquatic ecosystems through agricultural and industrial runoff, wastewater treatment effluent discharge, and atmospheric deposition. Cyanobacterial harmful algal blooms (CyanoHABs), which can produce toxins potent enough to cause human death, have been increasing in intensity, frequency, and spatial scale throughout the same time period as accelerated POP usage. Here, we provide a meta-analysis and suggest that POP stressors may be significantly aggravating nutrient-driven CyanoHABs by suppressing the growth of competing phytoplankton, and/or by indirectly or directly stimulating cyanobacterial growth

Brief of Feminists for Life of America, Professional Women\u27s Network, Birthright, Inc., Legal Action for Women, as Amici Curiae in Support of Respondents and Cross Petitioners - Planned Parenthood of Southeastern Pennsylvania v. Casey, 112 S. Ct. 2791 (1992)

Amici, representing women from all walks of life, are compelled by experience and conviction to advocate strongly that this Court reverse the vulnerable position of women caused by the lack of information given to women contemplating abortion. Amici respectfully urged this Court to affirm the ruling of the Court below, supporting the efforts of the women citizens of the Commonwealth of Pennsylvania to cause that government to exercise its police power to protect their health and safety by compelling the dissemination of the information necessary to make a fully informed decision

Ultraviolet Imaging Observations of the cD Galaxy in Abell 1795: Further Evidence for Massive Star Formation in a Cooling Flow

We present images from the Ultraviolet Imaging Telescope of the Abell 1795 cluster of galaxies. We compare the cD galaxy morphology and photometry of these data with those from existing archival and published data. The addition of a far--UV color helps us to construct and test star formation model scenarios for the sources of UV emission. Models of star formation with rates in the range \sim5-20M_{\sun}yr$^{-1}$ indicate that the best fitting models are those with continuous star formation or a recent ($\sim4$ Myr old) burst superimposed on an old population. The presence of dust in the galaxy, dramatically revealed by HST images complicates the interpretation of UV data. However, we find that the broad--band UV/optical colors of this cD galaxy can be reasonably matched by models using a Galactic form for the extinction law with $E_{B-V}=0.14$. We also briefly discuss other objects in the large UIT field of view.Comment: To appear in the Astrophysical Journal. 14 AAS preprint style pages plus 7 figure

A New Probe of the Molecular Gas in Galaxies: Application to M101

Recent studies of nearby spiral galaxies suggest that photodissociation regions (PDRs) are capable of producing much of the observed HI in galaxy disks. In that case, measurements of the HI column density and the far-ultraviolet (FUV) photon flux provide a new probe of the volume density of the local underlying H_2. We develop the method and apply it to the giant Scd spiral M101 (NGC 5457). We find that, after correction for the best-estimate gradient of metallicity in the ISM of M101 and for the extinction of the ultraviolet emission, molecular gas with a narrow range of density from 30-1000 cm^-3 is found near star- forming regions at all radii in the disk of M101 out to a distance of 12' (approximately 26 kpc), close to the photometric limit of R_25 = 13.5'. In this picture, the ISM is virtually all molecular in the inner parts of M101. The strong decrease of the HI column density in the inner disk of the galaxy at R_G < 10 kpc is a consequence of a strong increase in the dust-to-gas ratio there, resulting in an increase of the H_2 formation rate on grains and a corresponding disappearance of hydrogen in its atomic form.Comment: accepted for publication in The Astrophysical Journal (1 August 2000); 29 pages including 20 figures (7 gif); AAS LaTex; contact authors for full resolution versions of gif figure