Operational flow visualization techniques in the Langley Unitary Plan Wind Tunnel

The unitary plan wind tunnel (UPWT) uses in daily operation are shown. New ideas for improving the quality of established flow visualization methods are developed and programs on promising new flow visualization techniques are pursued. The unitary plan wind tunnel is a supersonic facility, referred to as a production facility, although the majority of tests are inhouse basic research investigations. The facility has two 4 ft. by 4 ft. test sections which span a Mach range from 1.5 to 4.6. The cost of operation is about $10 per minute. Problems are the time required for a flow visualization test setup and investigation costs and the ability to obtain consistently repeatable results. Examples of sublimation, vapor screen, oil flow, minitufts, schlieren, and shadowgraphs taken in UPWT are presented. All tests in UPWT employ one or more of the flow visualization techniques

Mechanical activation and cation site disorder of spinel-based ceramics

This research focuses on the processing and the effects that has on the cation disorder of magnesium-aluminate spinel based (MgAl2O4) ceramics. The first goal of this project was to determine the effects of high-energy milling, i.e., mechanical activation, on cation disorder (inversion) within the spinel structure. First, 1:1 molar ratios of MgO:Al2O3 ceramics were processed using two green processing methods, ball milling (XD) and SPEX milling (mechanical activation, MA) followed by a subsequent annealing treatment in air to form a single spinel phase in each powder sample. Neutron diffraction analysis was employed to determine the cation site occupancy and revealed that overall mechanical activation resulted in a lower degree of cation site inversion compared to the non-activated materials, about 0.12 was the largest value returned for the MA materials and 0.13 was the lowest value out of the XD samples. The second portion of this project was to investigate the synthesis, densification behavior, and crystallographic site occupancy for a high-entropy spinel (HES) (Co0.2Cu0.2Mg0.2Ni0.2Zn0.2)Al2O4. This was compared to several other compositions including a MgAl2O4, NiAl2O4 and (Mg0.5Ni0.5)Al2O4 (MAS, NAS, NMAS) specimens produced using the same methods. Each composition reacted to form a single phase, but analysis of x-ray diffraction (XRD) patterns revealed that the HES specimen had a degree of inversion of 0.4. The NAS and NMAS samples were also highly inverted whereas the MAS material had minimal cation disorder. --Abstract, page iv

Surface pressure data for a supersonic-cruise airplane configuration at Mach numbers of 2.30, 2.96, 3.30

The tabulated results of surface pressure tests conducted on the wing and fuselage of an airplane model in the Langley Unitary Plan wind tunnel are presented without analysis. The model tested was that of a supersonic-cruise airplane with a highly swept arrow-wing planform, two engine nacelles mounted beneath the wing, and outboard vertical tails. Data were obtained at Mach numbers of 2.30, 2.96, and 3.30 for angles of attack from -4 deg to 12 deg. The Reynolds number for these tests was 6,560,000 per meter

Vapor-screen technique for flow visualization in the Langley Unitary Plan Wind Tunnel

The vapor-screen technique for flow visualization, as developed for the Langley Unitary Plan Wind Tunnel, is described with evaluations of light sources and photographic equipment. Test parameters including dew point, pressure, and temperature were varied to determine optimum conditions for obtaining high-quality vapor-screen photographs. The investigation was conducted in the supersonic speed range for Mach numbers from 1.47 to 4.63 at model angles of attack up to 35 deg. Vapor-screen photographs illustrating various flow patterns are presented for several missile and aircraft configurations. Examples of vapor-screen results that have contributed to the understanding of complex flow fields and provided a basis for the development of theoretical codes are presented with reference to other research

Description and calibration of the Langley unitary plan wind tunnel

The two test sections of the Langley Unitary Plan Wind Tunnel were calibrated over the operating Mach number range from 1.47 to 4.63. The results of the calibration are presented along with a a description of the facility and its operational capability. The calibrations include Mach number and flow angularity distributions in both test sections at selected Mach numbers and tunnel stagnation pressures. Calibration data are also presented on turbulence, test-section boundary layer characteristics, moisture effects, blockage, and stagnation-temperature distributions. The facility is described in detail including dimensions and capacities where appropriate, and example of special test capabilities are presented. The operating parameters are fully defined and the power consumption characteristics are discussed

Surprisingly Little Population Genetic Structure In A Fungus-Associated Beetle Despite Its Exploitation Of Multiple Hosts

In heterogeneous environments, landscape features directly affect the structure of genetic variation among populations by functioning as barriers to gene flow. Resource-associated population genetic structure, in which populations that use different resources (e.g., host plants) are genetically distinct, is a well-studied example of how environmental heterogeneity structures populations. However, the pattern that emerges in a given landscape should depend on its particular combination of resources. If resources constitute barriers to gene flow, population differentiation should be lowest in homogeneous landscapes, and highest where resources exist in equal proportions. In this study, we tested whether host community diversity affects population genetic structure in a beetle (Bolitotherus cornutus) that exploits three sympatric host fungi. We collected B.cornutus from plots containing the three host fungi in different proportions and quantified population genetic structure in each plot using a panel of microsatellite loci. We found no relationship between host community diversity and population differentiation in this species; however, we also found no evidence of resource-associated differentiation, suggesting that host fungi are not substantial barriers to gene flow. Moreover, we detected no genetic differentiation among B.cornutus populations separated by several kilometers, even though a previous study demonstrated moderate genetic structure on the scale of a few hundred meters. Although we found no effect of community diversity on population genetic structure in this study, the role of host communities in the structuring of genetic variation in heterogeneous landscapes should be further explored in a species that exhibits resource-associated population genetic structure

Development of a tool to support person-centred medicine-focused consultations with stroke survivors

Objective: To develop a tool to support medicine-focused person-centred consultations between community pharmacists and stroke survivors. Method: Semi-structured interviews with 15 stroke survivors and 16 community pharmacists were conducted. Thematic analysis of the data was performed and emerging themes examined to determine their relevance to the principles of delivering person-centred care. Findings were used to generate a framework from which a consultation tool was created. Face validity and the feasibility of using the tool in practice were explored with participating pharmacists. Results: Three major themes were identified; personal, process and environmental factors. A tool, in two parts, was developed, A ‘Getting to know me’ form which would help the pharmacist to appreciate the individual needs of the stroke survivor and a consultation guide to facilitate the consultation process. Pharmacists considered that both were useful and would support a person-centred medicine-focussed consultation. Conclusion: A consultation tool, reflecting the needs of stroke survivors, has been developed and is feasible for use within community pharmacy practice. Practice implications: Pharmacists must recognise the individual needs of stroke survivors to ensure that they provide consultations which are truly person-centred. The tool developed could support medicine-related consultations with patients with other long term conditions

Pavlovian conditioning-induced hallucinations result from overweighting of perceptual priors

Some people hear voices that others do not, but only some of those people seek treatment. Using a Pavlovian learning task, we induced conditioned hallucinations in four groups of people who differed orthogonally in their voice-hearing and treatment-seeking statuses. People who hear voices were significantly more susceptible to the effect. Using functional neuroimaging and computational modeling of perception, we identified processes that differentiated voice-hearers from non-voice-hearers and treatment-seekers from non-treatment-seekers and characterized a brain circuit that mediated the conditioned hallucinations. These data demonstrate the profound and sometimes pathological impact of top-down cognitive processes on perception and may represent an objective means to discern people with a need for treatment from those without