Transonic wind-tunnel tests of an F-8 airplane model equipped with 12 and 14-percent thick oblique wings

An experimental investigation was conducted in the Ames 14-foot transonic wind tunnel to study the aerodynamic performance and stability characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing. Two elliptical planform (axis ratio = 8:1) wings, each having a maximum thickness of 12 and 14 percent, were tested. Longitudinal stability data were obtained with no wing and with each of the two wings set at sweep angles of 0, 45, and 60 deg. Lateral directional stability data were obtained for the 12 percent wing only. Test Mach numbers ranged from 0.6 to 1.2 in the unit Reynolds number range from 11.2 to 13.1 million per meter. Angles of attack were between -6 and 22 deg at zero sideslip. Angles of sideslip were between -6 and +6 deg for two angles of attack, depending upon the wing configuration

A common contrast pooling rule for suppression within and between the eyes

Recent work has revealed multiple pathways for cross-orientation suppression in cat and human vision. In particular, ipsiocular and interocular pathways appear to assert their influence before binocular summation in human but have different (1) spatial tuning, (2) temporal dependencies, and (3) adaptation after-effects. Here we use mask components that fall outside the excitatory passband of the detecting mechanism to investigate the rules for pooling multiple mask components within these pathways. We measured psychophysical contrast masking functions for vertical 1 cycle/deg sine-wave gratings in the presence of left or right oblique (645 deg) 3 cycles/deg mask gratings with contrast C%, or a plaid made from their sum, where each component (i) had contrast 0.5Ci%. Masks and targets were presented to two eyes (binocular), one eye (monoptic), or different eyes (dichoptic). Binocular-masking functions superimposed when plotted against C, but in the monoptic and dichoptic conditions, the grating produced slightly more suppression than the plaid when Ci $ 16%. We tested contrast gain control models involving two types of contrast combination on the denominator: (1) spatial pooling of the mask after a local nonlinearity (to calculate either root mean square contrast or energy) and (2) "linear suppression" (Holmes & Meese, 2004, Journal of Vision 4, 1080–1089), involving the linear sum of the mask component contrasts. Monoptic and dichoptic masking were typically better fit by the spatial pooling models, but binocular masking was not: it demanded strict linear summation of the Michelson contrast across mask orientation. Another scheme, in which suppressive pooling followed compressive contrast responses to the mask components (e.g., oriented cortical cells), was ruled out by all of our data. We conclude that the different processes that underlie monoptic and dichoptic masking use the same type of contrast pooling within their respective suppressive fields, but the effects do not sum to predict the binocular case

Transonic lateral and longitudinal control characteristics of an F-8 airplane model equipped with an oblique wing

The aerodynamic stability and control characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing was studied. The wing had an elliptical planform (axis ratio = 8:1), a maximum thickness of 12 percent, and was tested at three sweep angles, 0, 45, and 60 deg. Six-component force and moment data were measured at zero sideslip for angles of attack between -6 and +16 deg, with the left and right ailerons deflected one at a time at angles between -14 deg and +14. Further tests were made with the horizontal tail deflected -5 and +2.5 deg. Test Mach numbers ranged from 0.6 to 1.4 at a Reynolds number of 20 million/m

The Development of a Human Well-Being Index for the United States

The US Environmental Protection Agency (EPA) has developed a human well-being index (HWBI) that assesses the over-all well-being of its population at the county level. The HWBI contains eight domains representing social, economic and environmental well-being. These domains include 25 indicators comprised of 80 metrics and 22 social, economic and environmental services. The application of the HWBI has been made for the nation as a whole at the county level and two alternative applications have been made to represent key populations within the overall US population—Native Americans and children. A number of advances have been made to estimate the values of metrics for counties where no data is available and one such estimator—MERLIN—is discussed. Finally, efforts to make the index into an interactive web site are described

Ionization state, excited populations and emission of impurities in dynamic finite density plasmas: I. The generalized collisional-radiative model for light elements

The paper presents an integrated view of the population structure and its role in establishing the ionization state of light elements in dynamic, finite density, laboratory and astrophysical plasmas. There are four main issues, the generalized collisional-radiative picture for metastables in dynamic plasmas with Maxwellian free electrons and its particularizing to light elements, the methods of bundling and projection for manipulating the population equations, the systematic production/use of state selective fundamental collision data in the metastable resolved picture to all levels for collisonal-radiative modelling and the delivery of appropriate derived coefficients for experiment analysis. The ions of carbon, oxygen and neon are used in illustration. The practical implementation of the methods described here is part of the ADAS Project

Flow-Based Cytometric Analysis of Cell Cycle via Simulated Cell Populations

We present a new approach to the handling and interrogating of large flow cytometry data where cell status and function can be described, at the population level, by global descriptors such as distribution mean or co-efficient of variation experimental data. Here we link the “real” data to initialise a computer simulation of the cell cycle that mimics the evolution of individual cells within a larger population and simulates the associated changes in fluorescence intensity of functional reporters. The model is based on stochastic formulations of cell cycle progression and cell division and uses evolutionary algorithms, allied to further experimental data sets, to optimise the system variables. At the population level, the in-silico cells provide the same statistical distributions of fluorescence as their real counterparts; in addition the model maintains information at the single cell level. The cell model is demonstrated in the analysis of cell cycle perturbation in human osteosarcoma tumour cells, using the topoisomerase II inhibitor, ICRF-193. The simulation gives a continuous temporal description of the pharmacodynamics between discrete experimental analysis points with a 24 hour interval; providing quantitative assessment of inter-mitotic time variation, drug interaction time constants and sub-population fractions within normal and polyploid cell cycles. Repeated simulations indicate a model accuracy of ±5%. The development of a simulated cell model, initialized and calibrated by reference to experimental data, provides an analysis tool in which biological knowledge can be obtained directly via interrogation of the in-silico cell population. It is envisaged that this approach to the study of cell biology by simulating a virtual cell population pertinent to the data available can be applied to “generic” cell-based outputs including experimental data from imaging platforms

Development of FRET-Based Assays in the Far-Red Using CdTe Quantum Dots

Colloidal quantum dots (QDs) are now commercially available in a biofunctionalized form, and Förster resonance energy transfer (FRET) between bioconjugated dots and fluorophores within the visible range has been observed. We are particularly interested in the far-red region, as from a biological perspective there are benefits in pushing to ∼700 nm to minimize optical absorption (ABS) within tissue and to avoid cell autofluorescence. We report on FRET between streptavidin- (STV-) conjugated CdTe quantum dots, Qdot705-STV, with biotinylated DY731-Bio fluorophores in a donor-acceptor assay. We also highlight the changes in DY731-Bio absorptivity during the streptavidin-biotin binding process which can be attributed to the structural reorientation. For fluorescence beyond 700 nm, different alloy compositions are required for the QD core and these changes directly affect the fluorescence decay dynamics producing a marked biexponential decay with a long-lifetime component in excess of 100 nanoseconds. We compare the influence of the two QD relaxation routes upon FRET dynamics in the presence of DY731-Bio

A numerical evaluation of next generation additive layer manufactured inter-layer channel heat exchanger

A Concept Heat Exchanger (HE) design manufactured using the Additive Layer Manufacturing (ALM) technique Selective Laser Melting (SLM) is proposed and numerically evaluated. It is composed of a HE corrugation which introduces inter-layer flow conduits between the parallel HE layers of the same fluid. These pathways are provided by hollow elliptical tubes which serve several functions: to disturb the flow to promote heat transfer, to provide additional heat transfer area and to minimise flow maldistribution inside the HE core. The corrugation is incorporated into a counter-flow prototype HE unit model meaning to exploit the installation volume and design freedom made possible via ALM. Three Computational Fluid Dynamics (CFD) models are utilised to evaluate the performance of the proposed HE unit. Firstly, a traditional two step HE design methodology is utilised which works by initially evaluating a fully symmetric channel of the proposed HE corrugation (termed single channel). Then the results this model are incorporated into a simplified HE unit model. The second approach evaluates the HE unit performance based on a fully detailed CFD analysis that fully resolves flow and heat transfer inside the HE core. The third modelling approach involves splitting the inter-layer HE unit model into parts, which results in HE header models and allows simplification of the HE core into a single corrugation period width HE core model (termed superchannel). The results of these models are then compared to a conventional pin–fin HE unit model, formed by blocking the elliptical inter-layer conduits. It was found that in all the HE unit models the pressure drop is similar whilst the heat transfer was enhanced by between 7% and 13% in terms of the overall ΔT by the inter-layer channels (increasing with the Reynolds number). All simulations were completed using a CFD package OpenFOAM

A multi-scale conjugate heat transfer modelling approach for corrugated heat exchangers

The paper compares two serrated plate-fin Heat Exchanger (HE) corrugation modelling methods using Computational Fluid Dynamics (CFD). The first method follows closely recent literature studies and models a finite length single channel of a corrugation layer inside the HE core. The second method utilises the conjugate heat transfer methodology and models a section of the HE core with both cold and hot fluid streams separated by a solid conducting wall (HE corrugation). The results of latter model are then extrapolated for the full dimensions of a HE core layer to obtain flow and heat transfer characteristics. The conjugate heat transfer analysis methodology presented is novel and eliminates the need for analytical/empirical modelling currently widely used within industry. Furthermore, it provides more detailed information about the flow and heat transfer inside the HE core enabling potential for more efficient HE designs. Predictions at the corrugation level were carried out at with mesh independence studies completed for all the computational domains. The results obtained in the HE corrugation predictions were then implemented to the multi-scale HE unit model where the flow inside the HE core was modelled using two porous media simplifications whilst the heat transfer was simplified using the effectiveness source term. The HE unit predictions were validated against industrial experimental data with good agreement found between the numerical and experimental results. All the simulations were completed using the open-source CFD package OpenFOAM

Experimental and numerical study of the additive layer manufactured inter-layer channel heat exchanger

In this paper the performance of a recently patented additive layer manufactured (ALM) concept inter-layer heat exchanger (HE) is evaluated experimentally and numerically. Two numerical HE models are developed using the conjugate heat transfer (CHT) methodology. The first is an idealised HE core model, consisting of a single period width HE corrugation section (termed superchannel). The second approach uses a fully detailed HE unit model which resolves the flow and heat transfer inside the complete HE unit. A close agreement was found between the HE unit simulations and the experimentally obtained results, such that the fully detailed HE model could be validated. It was also shown that, a full CHT approach is necessary to accurately evaluate complex inter-layer ALM HE core flow and heat transfer behaviour and can serve as an approach for optimising HE designs. The results also reinforce the occurrence of the inter-layer flow mixing inside the HE core of the same flow streams and allows the mass flow to redistribute inside the HE core which is impossible with the current HE generation geometries. The superchannel model results in a slight over-estimation in heat transfer ( K on average) making the simplified model acceptable as a conservative estimate. Using validated simulations a parametric study was conducted by changing the solid properties of the full CHT HE model to aluminium to investigate the effects of a significantly more conductive material. This resulted in higher heat transfer effectiveness () of the HE unit. All the simulations were carried out using CFD package OpenFOAM