Influence of optimized leading-edge deflection and geometric anhedral on the low-speed aerodynamic characteristics of a low-aspect-ratio highly swept arrow-wing configuration

An investigation conducted in the Langley 7 by 10 foot tunnel to determine the influence of an optimized leading-edge deflection on the low speed aerodynamic performance of a configuration with a low aspect ratio, highly swept wing. The sensitivity of the lateral stability derivative to geometric anhedral was also studied. The optimized leading edge deflection was developed by aligning the leading edge with the incoming flow along the entire span. Owing to spanwise variation of unwash, the resulting optimized leading edge was a smooth, continuously warped surface for which the deflection varied from 16 deg at the side of body to 50 deg at the wing tip. For the particular configuration studied, levels of leading-edge suction on the order of 90 percent were achieved. The results of tests conducted to determine the sensitivity of the lateral stability derivative to geometric anhedral indicate values which are in reasonable agreement with estimates provided by simple vortex-lattice theories

An indole trimer: synthesis, self-assembly and applications

The organic semiconductor, the indole -5- carboxylic acid asymmetric trimer (ICAT), was chemically synthesised using a new procedure. Self- assembly of ICAT in solution, produced narrowly dispersed discotic nanoparticles that are stable in solution and transferable between surfaces. Highly ordered ICAT bulk molecular and nanoparticle thin films were produced through controlled assembly of ICAT at the solution /solid interface, using glass substrates functionalised with a variety of self assembled monolayers (SAMs). Two films, in particular, on the hydroxyl and the amine -functionalised substrates had extremely well ordered microstructures, suitable for device application.An immersion based deposition technique was developed, where gold and SAM - functionalised glass substrates were immersed in ICAT solutions made with solvents with a range of polarities. At short immersion times, bulk or particulate films were deposited, as a function of immersion solvent. Longer immersion times produced size tailored vertically aligned nanorod and nanowire arrays, as a function of immersion solvent. The immersion time also controlled both the rod density and rod orientation on the substrates. The results were interpreted in terms of heterogeneous nucleation and subsequent growth. Solvophobic forces induced homogeneous nucleation rather than heterogeneous nucleation, in the immersion systems with water and hydrocarbon based immersion solvents. Aligned nanorods and nanowires were assembled on gold and hydroxyl -functionalised glass substrates when polar aprotic immersion solvents were used. There was no obvious correlation between nanostructure dimensions and solvent polarity in these experiments. This is the first time vertically aligned nanorod arrays have been fabricated with small organic functional molecules, through a solution based technique (non -template).Solution based deposition techniques developed here were used to deposit ICAT onto field effect transistors (FETs), resulting in devices with a range of ICAT film morphologies. Single crystal devices were also produced where the ICAT crystal bridged the active channel, defined as the gap between the source and drain electrodes. Several chips, with over 20 FETs on each chip, with each ICAT film morphology type, were fabricated. Selected chips had consistent, reproducible current/voltage (IV) outputs that varied within « one order of magnitude, when probed on all areas. The devices produced n and p -type unipolar activity and the onset of ambipolar activity in ambient conditions, at low voltage probing ranges. Carrier type was dependent on the film morphology. Device lifetime was dependent on film thickness

The entanglement of few-particle systems when using the local-density approximation

In this chapter we discuss methods to calculate the entanglement of a system using density-functional theory. We firstly introduce density-functional theory and the local-density approximation (LDA). We then discuss the concept of the `interacting LDA system'. This is characterised by an interacting many-body Hamiltonian which reproduces, uniquely and exactly, the ground state density obtained from the single-particle Kohn-Sham equations of density-functional theory when the local-density approximation is used. We motivate why this idea can be useful for appraising the local-density approximation in many-body physics particularly with regards to entanglement and related quantum information applications. Using an iterative scheme, we find the Hamiltonian characterising the interacting LDA system in relation to the test systems of Hooke's atom and helium-like atoms. The interacting LDA system ground state wavefunction is then used to calculate the spatial entanglement and the results are compared and contrasted with the exact entanglement for the two test systems. For Hooke's atom we also compare the entanglement to our previous estimates of an LDA entanglement. These were obtained using a combination of evolutionary algorithm and gradient descent, and using an LDA-based perturbative approach. We finally discuss if the position-space information entropy of the density---which can be obtained directly from the system density and hence easily from density-functional theory methods---can be considered as a proxy measure for the spatial entanglement for the test systems.Comment: 12 pages and 5 figures

Leading-edge deflection optimization for a highly swept arrow wing configuration

Tests were also conducted to determine the sensitivity of the lateral stability derivative C sub l sub beta to geometric anhedral. The optimized leading edge deflection was developed by aligning the leading edge with the incoming flow along the entire span. Owing to the spanwise variation of upwash, the resulting optimized leading edge was a smooth, continuously warped surface. For the particular configuration studied, levels of leading edge suction on the order of 90 percent were achieved with the smooth, continuously warped leading edge contour. The results of tests conducted to determine the sensitivity of C sub l sub beta to geometric anhedral indicate values of delta C sub l sub beta/delta T which are in reasonable agreement with estimates provided by simple vortex lattice theories

Two populations of X-ray pulsars produced by two types of supernovae

Two types of supernova are thought to produce the overwhelming majority of neutron stars in the Universe. The first type, iron-core collapse supernovae, occurs when a high-mass star develops a degenerate iron core that exceeds the Chandrasekhar limit. The second type, electron-capture supernovae, is associated with the collapse of a lower-mass oxygen-neon-magnesium core as it loses pressure support owing to the sudden capture of electrons by neon and/or magnesium nuclei. It has hitherto been impossible to identify the two distinct families of neutron stars produced in these formation channels. Here we report that a large, well-known class of neutron-star-hosting X-ray pulsars is actually composed of two distinct sub-populations with different characteristic spin periods, orbital periods and orbital eccentricities. This class, the Be/X-ray binaries, contains neutron stars that accrete material from a more massive companion star. The two sub-populations are most probably associated with the two distinct types of neutron-star-forming supernovae, with electron-capture supernovae preferentially producing system with short spin period, short orbital periods and low eccentricity. Intriguingly, the split between the two sub-populations is clearest in the distribution of the logarithm of spin period, a result that had not been predicted and which still remains to be explaine

Using Rituals for Intervention Refinement

In this paper we propose a culture-based health promotion/disease prevention intervention model.  This model, which is family-based, incorporates a life course perspective, which involves the identification of individual developmental milestones, and incorporates aspects of culture that have been widely used across cultures to influence behavior and mark important developmental transitions. Central among those cultural traits is the ritual, or rite of passage, which, for millennia, has been used to teach the skills associated with developmental task mastery and move individuals, and their families, through life stages so that they reach certain developmental milestones. Family rituals, such as eating dinner together, can serve as powerful leverage points to support health behavior change, and serve as unique intervention delivery strategies that not only influence behavior, but further strengthen families.

Testing density-functional approximations on a lattice and the applicability of the related Hohenberg-Kohn-like theorem

We present a metric-space approach to quantify the performance of approximations in lattice density-functional theory for interacting many-body systems and to explore the regimes where the Hohenberg-Kohn-type theorem on fermionic lattices is applicable. This theorem demonstrates the existence of one-to-one mappings between particle densities, wave functions and external potentials. We then focus on these quantities, and quantify how far apart in metric space the approximated and exact ones are. We apply our method to the one-dimensional Hubbard model for different types of external potentials, and assess the regimes where it is applicable to one of the most used approximations in density-functional theory, the local density approximation (LDA). We find that the potential distance may have a very different behaviour from the density and wave function distances, in some cases even providing the wrong assessments of the LDA performance trends. We attribute this to the systems reaching behaviours which are borderline for the applicability of the one-to-one correspondence between density and external potential. On the contrary the wave function and density distances behave similarly and are always sensitive to system variations. Our metric-based method correctly predicts the regimes where the LDA performs fairly well and the regimes where it fails. This suggests that our method could be a practical tool for testing the efficiency of density-functional approximations