Modification and development of the external tank hydrogen vent umbilical system for the space shuttle vehicle

The design and development of a new T-O lock and secondary release mechanism which is being introduced to the ET Hydrogen Vent Umbilical System for the next launch of the Space Shuttle Vehicle is described. Critical analysis of the system in early 1986 indicated the need for an improvement in the secondary release system. The new T-O lock increases the clearance with the vehicle during secondary disconnect and is described

1,3,4,6-Tetramethyl-1,4-dihydro-1,2,4,5-tetrazine, C_6H_(12)N_4

M_r =140∙19, monoclinic, P2_1/n, a = 10∙612(3), b=6∙820(1), c= 10∙975 (2) Å, β=95∙31(2)°, V=790.9(5) Å^3, Z=4, D_m=1.13(5) (flotation), D_x = 1∙177 g cm^(-3), Mo Kα, λ = 0.71073 Å, μ= 0.848 cm^(-1), F(000) = 304, T= 295 K, R = 0∙077 for 704 observed reflections. This potentially antiaromatic or homoaromatic ring system has a flattened boat conformation with both N-methyls in equatorial positions. Bond angles and distances (excluding H's) predicted to be symmetry equivalent exhibit variations of 0.002-0.014 Å and 0.0-2.0°. Substantial delocalization of the electron lone pairs of N(1) and N(4) is found

Temperature influence on the carbon isotopic composition of Orbulina universa and Globigerina bulloides (planktonic foraminifera)

Laboratory experiments with the planktonic foraminifera Orbulina universa (symbiotic) and Globigerina bulloides (nonsymbiotic) were used to examine the effects of temperature, irradiance (symbiont photosynthesis), [CO32-], [HPO42-], and ontogeny on shell d13C values. In ambient seawater ([CO32-] = 171 mmol kg-1), the d13C of O. universa shells grown under low light (LL) levels is insensitive to temperature and records the d13C value of seawater TCO2. In contrast, the d13C of high light (HL) shells increases ~0.4‰ across 15-25°C (+0.050‰/°C). This suggests that the d13C enrichment due to symbiont photosynthetic activity is temperature-dependent. A comparison of HL O. universa grown in elevated [CO32-] seawater with ambient specimens shows that temperature does not affect the slope of the d13C/[CO32-] relationship previously described [Spero et al., 1997]. The d13C of G. bulloides shells decreases across the 15-24°C temperature range and d13C:temperature slopes decrease with increasing shell size (-0.13, -0.10, and -0.09‰/°C in 11- 12-, and 13-chambered shells, respectively). The pattern of lower d13C values at higher temperatures likely results from the incorporation of more respired CO2 into the shell at higher metabolic rates. The d13C of HL O. universa increases with increased seawater [HPO42-]

Persistent topographic development along a strike-slip fault system: The Mount McKinley restraining bend

The Denali Fault is a major strike-slip fault extending from British Colombia, into western Alaska. Mount McKinley, at 6,114 m, is the highest peak in North America and is located to the south of a bend in the Denali Fault (Fig.1). To the north, at the apex of the bend in the fault, Peters Dome (3,221 m) is the highest peak and north-side peak elevations rapidly decrease moving away from the bend’s apex

The relative effect of particles and turbulence on acoustic scattering from deep sea hydrothermal vent plumes revisited

Author Posting. © Acoustical Society of America, 2017. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 141 (2017): 1446–1458, doi:10.1121/1.4974828.The relative importance of suspended particles and turbulence as backscattering mechanisms within a hydrothermal plume located on the Endeavour Segment of the Juan de Fuca Ridge is determined by comparing acoustic backscatter measured by the Cabled Observatory Vent Imaging Sonar (COVIS) with model calculations based on in situ samples of particles suspended within the plume. Analysis of plume samples yields estimates of the mass concentration and size distribution of particles, which are used to quantify their contribution to acoustic backscatter. The result shows negligible effects of plume particles on acoustic backscatter within the initial 10-m rise of the plume. This suggests turbulence-induced temperature fluctuations are the dominant backscattering mechanism within lower levels of the plume. Furthermore, inversion of the observed acoustic backscatter for the standard deviation of temperature within the plume yields a reasonable match with the in situ temperature measurements made by a conductivity-temperature-depth instrument. This finding shows that turbulence-induced temperature fluctuations are the dominant backscattering mechanism and demonstrates the potential of using acoustic backscatter as a remote-sensing tool to measure the temperature variability within a hydrothermal plume.We thank the National Science Foundation for support (NSF Award Nos. OCE-0824612 and OCE-1234163 to APL-UW; NSF Award Nos. OCE-0825088 and OCE-1234141 to Rutgers)