An experimental study of massive blowing from a nosetip during Jovian entry

The fluid dynamic structure and stability of the boundary layer and shock layer ahead of a highly blowing heat shield in an environment simulating entry into the Jovian atmosphere were investigated. The experimental studies were conducted in the Calspan 96 in shock tunnel with a freestream of a H2/He mixture at Mach numbers above 10. Measurements of heat transfer and pressure were made on the porous model surface, and high-speed schlieren photography was used to examine the structure and stability of the shock layer. Results are presented which show how the heat transfer and shock layer stability vary for gases of different molecular weights for a range of Reynolds numbers and mass-addition rates

An analytical study of separated flows induced by shock wave - Boundary layer interaction

Analytical study of separated flows induced by shock wave-boundary layer interactio

The fatigue behavior of materials for the supersonic transport

Crack propagation behavior, residual static strength, and base fatigue strength of supersonic transport skin materia

Facilitation of trialogic spaces: reflections from Irish and Scottish online lesson studies

Digital innovations in teacher education have continued to evolve since the Coronavirus pandemic. As such, there has been recognition of the need to further examine the affordances and constraints of digitally mediated learning environments (Brown-Wilsher, 2021; White & Zimmerman, 2021). In response, this paper draws on the concept of trialogue (Hakkarainen, 2009), i.e. technology mediated dialogue, where digital tools are drawn on to make deliberate building and creation of knowledge accessible. Trialogue involves iterative communication and exchange of ideas in order to develop shared objects (Paavola & Hakkarainen, 2014), which can consist of artefacts, for example, lesson plans; and practices, such as pedagogical techniques. The paper focuses on two different Online Lesson Study projects facilitated by the authors, which took place in Scotland and Ireland. Insights gleaned from each project illustrating trialogue in action are shared, in order to illuminate the potential of trialogic space for enabling teachers’ collaborative learning

Spectroscopic Confirmation of a Radio-Selected Galaxy Overdensity at z=1.11

We report the discovery of a galaxy overdensity at z=1.11 associated with the z=1.110 high-redshift radio galaxy MG0442+0202. The group, CL0442+0202, was found in a near-infrared survey of z>1 radio galaxies undertaken to identify spatially-coincident regions with a high density of objects red in I-K' color, typical of z>1 elliptical galaxies. Spectroscopic observations from the Keck telescope reveal five galaxies within 35" of MG0442+0202 at 1.10<z<1.11. These member galaxies have broad-band colors and optical spectra consistent with passively-evolving elliptical galaxies formed at high redshift. A 45ks Chandra X-Ray Observatory observation detects the radio galaxy and four point sources within 15" of the radio galaxy, corresponding to a surface density two orders of magnitude higher than average for X-ray sources at these flux levels, S(0.5-2keV) > 5e-16 erg/cm2/s. One of these point sources is identified with a radio-quiet, typeII quasar at z=1.863, akin to sources recently reported in deep Chandra surveys. The limit on an extended hot intracluster medium in the Chandra data is S(1-6keV) < 1.9e-15 erg/cm2/s (3-sigma, 30" radius aperture). Though the X-ray observations do not confirm the existence of a massive, bound cluster at z>1, the success of the optical/near-infrared targeting of early-type systems near the radio galaxy validates searches using radio galaxies as beacons for high-redshift large-scale structure. We interpret CL0442+0202 to be a massive cluster in the process of formation.Comment: 23 pages, 7 figure

Growth inhibition of cytosolic Salmonella by caspase-1 and caspase-11 precedes host cell death

Sensing bacterial products in the cytosol of mammalian cells by NOD-like receptors leads to the activation of caspase-1 inflammasomes, and the production of the pro-inflammatory cytokines interleukin (IL)-18 and IL-1β. In addition, mouse caspase-11 (represented in humans by its orthologs, caspase-4 and caspase-5) detects cytosolic bacterial LPS directly. Activation of caspase-1 and caspase-11 initiates pyroptotic host cell death that releases potentially harmful bacteria from the nutrient-rich host cell cytosol into the extracellular environment. Here we use single cell analysis and time-lapse microscopy to identify a subpopulation of host cells, in which growth of cytosolic Salmonella Typhimurium is inhibited independently or prior to the onset of cell death. The enzymatic activities of caspase-1 and caspase-11 are required for growth inhibition in different cell types. Our results reveal that these proteases have important functions beyond the direct induction of pyroptosis and proinflammatory cytokine secretion in the control of growth and elimination of cytosolic bacteria

Shuttle Return-to-Flight IH-108 Aerothermal Test at CUBRC - Flow Field Calibration and CFD

This paper discusses one specific aspect of the Shuttle Retrun-To-Flight IH-108 Aerothermal Test at Calspan-University of Buffalo Research Center (CUBRC), the test flow field calibration. It showed the versatility of the CUBRC Large Energy National Shock Tunnel (LENS) II wind tunnel for an aerothermal test with unique and demanding requirements. CFD analyses were used effectively to extend the test range at the low end of the Mach range. It demonstrated how ground test facility and CFD synergy can be utilitzed iteratively to enhance the confidence in the fedility of both tools. It addressed the lingering concerns of the aerothermal community on use of inpulse facility and CFD analysis. At the conclusion of the test program, members from the NASA Marshall (MSFC), CUBRC and USA (United Space Alliance) Consultants (The Grey Beards) were asked to independently verify the flight scaling data generated by Boeing for flight certification of the re-designed external tank (ET) components. The blind test comparison showed very good results

Studies of shock/shock interaction on smooth and transpiration-cooled hemispherical nosetips in hypersonic flow

A program of experimental research and analysis was conducted to examine the heat transfer and pressure distributions in regions of shock/shock interaction over smooth and transpiration-cooled hemispherical noseshapes. The objective of this investigation was to determine whether the large heat transfer generated in regions of shock/shock interaction can be reduced by transpiration cooling. The experimental program was conducted at Mach numbers of 12 to 16 in the Calspan 48-Inch Shock Tunnel. Type 3 and type 4 interaction regions were generated for a range of freestream unit Reynolds numbers to provide shear layer Reynolds numbers from 10 exp 4 to 10 exp 6 to enable laminar and turbulent interaction regions to be studied. Shock/shock interactions were investigated on a smooth hemispherical nosetip and a similar transpiration-cooled nosetip, with the latter configuration being examined for a range of surface blowing rates up to one-third of the freestream mass flux. While the heat transfer measurements on the smooth hemisphere without shock/shock interaction were in good agreement with Fay-Riddell predictions, those on the transpiration-cooled nosetip indicated that its intrinsic roughness caused heating-enhancement factors of over 1.5. In the shock/shock interaction studies on the smooth nosetip, detailed heat transfer and pressure measurements were obtained to map the variation of the distributions with shock-impingement position for a range of type 3 and type 4 interactions. Such sets of measurements were obtained for a range of unit Reynolds numbers and Mach numbers to obtain both laminar and turbulent interactions. The measurements indicated that shear layer transition has a significant influence on the heating rates for the type 4 interaction as well as the anticipated large effects on type 3 interaction heating. In the absence of blowing, the peak heating in the type 3 and type 4 interaction regions, over the transpiration-cooled model, did not appear to be influenced by the model's rough surface characteristics. The studies of the effects of the transpiration cooling on type 3 and type 4 shock/shock interaction regions demonstrated that large surface blowing rates had significant effect on the structure of the flowfield, enlarging the shock layer and moving the region of peak-heating interaction around the body