The wakes of spheres in a still environment were studied for sphere Reynolds numbers Re in the range 30-4000. The experiments consisted of towed spheres in quiescent baths of glycerin and water mixtures. Measurements included dye traces illuminated by a laser light sheet for visualization and laser velocimetry for streamwise velocities. The recirculation region on the downstream side of the sphere was stable and symmetric for Re < 200, stable and unsymmetric for 200 280. Three wake regions were identified: a fast-decay region that was observed only when vortex shedding was present, followed in succession by turbulent and laminar wake regions. Vortex shedding increased the distance to the onset of the turbulent wake region by an order of magnitude due to the presence of the fast-decay wake region. Mean velocities within the turbulent and laminar wake regions scaled according to classical similarity theories, with transition between these regions at conditions where their estimates of mean streamwise velocities along the axis were the same: this occurred at a local wake Reynolds number Re H -10. Within the turbulent wake region, turbulence intensities along the axis were roughly 85% for Re w > 70; however, as the onset of the laminar wake region was approached, turbulence intensities along the axis were proportional to Re w 1/4 , which is consistent with scaling proposed earlier for the final decay period of axisymmetric wakes. Nomenclature a = velocity decay exponent in fast-decay wake region C -constant for final decay period, Eq. (11) CD = drag coefficient d = sphere diameter £ = characteristic wake width, Eq. (3) t t = scaled characteristic wake width, Eq. (9) R = sphere radius Re = sphere Reynolds number, dU s /i> Re w = local wake Reynolds number, tu c /v r = radial distance t = time U s = sphere velocity (C/ 0 )/ = velocity scale for turbulent wake region u = mean streamwise velocity «' = rms streamwise velocity fluctuation x = streamwise distance from center of sphere 0 = initial momentum thickness of wake, Eq. (1) v = kinematic viscosity Subscripts c = centerline value cm = uncorrected centerline value o = virtual origin condition tr = transition from turbulent to laminar wake oo = ambient condition

In this study, we used an argon-based round atmospheric-pressure plasma jet (APPJ) for enhancing wound healing in streptozotocin (STZ) induced diabetic rats. The APPJ was characterized by optical emission spectroscopy. We induced Type 1 and Type 2 diabetes in rats with different amounts of STZ combined with normal and high-fat diets, respectively. The wound area ratio of all the plasma-treated normal and diabetic groups was greatly reduced (up to 30%) compared with that of the untreated groups during healing. Histological analysis revealed faster re-epithelialization, collagen deposition, less inflammation, and a complete skin structure in the plasma-treated groups was found as compared with the untreated control groups. In addition, the new blood vessels of plasma-treated tissues decreased more than untreated tissues in the middle (Day 14) and late (Day 21) stages of wound healing. The plasma-treated wounds demonstrated more transforming growth factor beta (TGF-β) expression in the early stage (Day 7), whereas they decreased in the middle and late stages of wound healing. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) increased after plasma treatment. In addition, plasma-treated water had a higher concentration of hydrogen peroxide, nitrite and nitrate when the plasma treatment time was longer. In summary, the proposed argon APPJ based on the current study could be a potential tool for treating diabetic wounds.

Context. This paper describes the initial modelling of gas and dust data acquired in August and September 2014 from the European Space Agency's Rosetta spacecraft when it was in close proximity to the nucleus of comet 67P/Churyumov-Gerasimenko. Aims. This work is an attempt to provide a self-consistent model of the innermost gas and dust coma of the comet, as constrained by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) data set for the gas and by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) data set for the dust. Methods. The model uses a previously developed shape model for the nucleus, and from this the water sublimation rate and gas temperatures at the surface are computed with a simple thermal model. The gas expansion is modelled with a 3D parallel implementation of a Direct Simulation Monte Carlo algorithm. A dust drag algorithm is then used to produce dust densities in the coma, which are then converted to brightnesses using Mie theory and a line-of-sight integration. Results. We show that a purely insolation-driven model for surface outgassing does not produce a reasonable fit to ROSINA/COPS data. A stronger source in the "neck" region of the nucleus (region Hapi) is needed to match the observed modulation of the gas density in detail. This agrees with OSIRIS data, which shows that the dust emission from the "neck" was dominant in the August-September 2014 time frame. The current model matches this observation reasonably if a power index of 2-3 for the dust size distribution is used. A better match to the OSIRIS data is seen by using a single large particle size for the coma. Conclusions. We have shown possible solutions to the gas and dust distributions in the inner coma, which are consistent with ROSINA and OSIRIS data.

The structure of sphere wakes in a turbulent environment was measured over the following test range: sphere Reynolds numbers from 135 to 1560, ambient turbulence intensities of roughly 4%, ratios of streamwise spatial integral scales to sphere diameters of 11-59, and ratios of Kolmogorov length scales to sphere diameters of 0.08-0.80. At these conditions, some phenomena observed for sphere wakes at comparable Reynolds numbers in nonturbulent environments were suppressed, like the fast-decaying and self-preserving turbulent wake regions; instead, while the wakes were turbulent, their mean streamwise velocities scaled like self-preserving laminar wakes but with enhanced viscosities due to turbulence. Effective turbulent viscosities were relatively independent of position and ratios of integral length scales and Kolmogorov microscales to sphere diameters; however, they progressively increased with sphere Reynolds numbers. Low and high Reynolds number regimes were observed, separated by a transition regime involving sphere Reynolds numbers in the range from 300 to 600, which was associated with conditions where effects of vortex shedding were prominent in the temporal power spectra measured in the near-wake region.

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