An analysis of performance estimation methods for aircraft

Measurements and analytical extrapolation validity in predicting full scale flight performance from model wind tunnel test

Spontaneous Scale Symmetry Breaking in 2+1-Dimensional QED at Both Zero and Finite Temperature

A complete analysis of dynamical scale symmetry breaking in 2+1-dimensional QED at both zero and finite temperature is presented by looking at solutions to the Schwinger-Dyson equation. In different kinetic energy regimes we use various numerical and analytic techniques (including an expansion in large flavour number). It is confirmed that, contrary to the case of 3+1 dimensions, there is no dynamical scale symmetry breaking at zero temperature, despite the fact that chiral symmetry breaking can occur dynamically. At finite temperature, such breaking of scale symmetry may take place.Comment: 12 pages, no figures, uses RevTeX4-bet

Nanolithography for metallic quasi crystals for nanobio applications

There is currently an urgent need to develop micro and nanotechnique for the fabrications of quasi periodic crystals in a plane for the study and applications of novel optical properties when light propagating in or through such a photonic structures with fold symmetries (10 fold symmetry in this work). It has been clear that quasi periodical crystals in dielectrics with various fold symmetries also exhibits complete photonic band gap (PBG) property as periodical photonic crystals do. However, the novel physical properties related to the interactions of electromagnetic waves with metallic holes arrays in quasi periodical order (metallic quasi crystals) is being discovered both theoretically and experimentally, which demands technical development for the construction of theoretically designed structures. [1] In this work, we report a nanofabrication technique recently developed for the replication of quasi crystal in 100 nm Al on a slab (quartz wafer in this work) by electron beam lithography using chemically amplified resist, UVN-30. A wealth of novel photonic behaviours of lights vertically incident through the q-crystal were observed

The GTC exoplanet transit spectroscopy survey X. Stellar spots versus Rayleigh scattering: the case of HAT-P-11b

Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be detected from ground or space based telescopes, however, stellar activity in the form of spots can mimic Rayleigh scattering in the observed transmission spectrum. Quantifying this phenomena is key to our correct interpretation of exoplanet atmospheric properties. We obtained long-slit optical spectroscopy of two transits of HAT-P-11b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at Gran Telescopio Canarias (GTC) on August 30 2016 and September 25 2017. We integrated the spectrum of HAT-P-11 and one reference star in several spectroscopic channels across the $\lambda\sim$ 400-785 nm region, creating numerous light curves of the transits. We fit analytic transit curves to the data taking into account the systematic effects and red noise present in the time series in an effort to measure the change of the planet-to-star radius ratio ($R_\mathrm{p}/R_\mathrm{s}$) across wavelength. By fitting both transits together, we find a slope in the transmission spectrum showing an increase of the planetary radius towards blue wavelengths. A closer inspection to the transmission spectrum of the individual data sets reveals that the first transit presents this slope while the transmission spectrum of the second data set is flat. Additionally we detect hints of Na absorption in the first night, but not in the second. We conclude that the transmission spectrum slope and Na absorption excess found in the first transit observation are caused by unocculted stellar spots. Modeling the contribution of unocculted spots to reproduce the results of the first night we find a spot filling factor of $\delta=0.62^{+0.20}_{-0.17}$ and a spot-to-photosphere temperature difference of $\Delta T = 429^{+184}_{-299}$ K.Comment: Accepted for publication in Astronomy & Astrophysics, 13 page

PATENT LICENSING BY MEANS OF AN AUCTION: INTERNAL VS. EXTERNAL PATENTEE

An independent research laboratory owns a patented process innovation that can be licensed by means of an auction to two Cournot duopolists producing differentiated goods. For large innovations and close enough substitute goods the patentee auctions o¤ only one license, preventing the full diffusion of the innovation. For this range of parameters, however, if the laboratory merged with one of the firms in the industry, full technology diffusion would be implemented as the merged entity would always license the innovation to the rival firm. This explains that, in this context, a vertical merger is both profitable and welfare improving.Patent licensing, two-part tariff contracts, vertical mergers

On linear coupling of acoustic and cyclotron waves in plasma flows

It is found that in magnetized electrostatic plasma flows the velocity shear couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable conditions, to their efficient reciprocal transformations. It is shown that in a two-dimensional setup this coupling has a remarkable feature: it is governed by equations that are exactly similar to the ones describing coupling of sound waves with internal gravity waves [Rogava & Mahajan: Phys. Rev. E vol.55, 1185 (1997)] in neutral fluid flows. Using another noteworthy quantum mechanical analogy we calculate transformation coefficients and give fully analytic, quantitative description of the coupling efficiency for flows with low shearing rates.Comment: 5 pages, no figures. Submitted to "Physics of Plasmas

The GTC exoplanet transit spectroscopy survey. VII. Detection of sodium in WASP-52b's cloudy atmosphere

We report the first detection of sodium absorption in the atmosphere of the hot Jupiter WASP-52b. We observed one transit of WASP-52b with the low-resolution Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the 10.4 m Gran Telescopio Canarias (GTC). The resulting transmission spectrum, covering the wavelength range from 522 nm to 903 nm, is flat and featureless, except for the significant narrow absorption signature at the sodium doublet, which can be explained by an atmosphere in solar composition with clouds at 1 mbar. A cloud-free atmosphere is stringently ruled out. By assessing the absorption depths of sodium in various bin widths, we find that temperature increases towards lower atmospheric pressure levels, with a positive temperature gradient of 0.88 +/- 0.65 K/km, possibly indicative of upper atmospheric heating and a temperature inversion.Comment: 6 pages, 5 figures, accepted for publication in A&A Lette

Eigenvalue correlations on Hyperelliptic Riemann surfaces

In this note we compute the functional derivative of the induced charge density, on a thin conductor, consisting of the union of g+1 disjoint intervals, $J:=\cup_{j=1}^{g+1}(a_j,b_j),$ with respect to an external potential. In the context of random matrix theory this object gives the eigenvalue fluctuations of Hermitian random matrix ensembles where the eigenvalue density is supported on J.Comment: latex 2e, seven pages, one figure. To appear in Journal of Physics

Spatial Structure of Ion Beams in an Expanding Plasma

We report spatially resolved perpendicular and parallel, to the magnetic field, ion velocity distribution function (IVDF) measurements in an expanding argon helicon plasma. The parallel IVDFs, obtained through laser induced fluorescence (LIF), show an ion beam with v ≈ 8000 m/s flowing downstream and confined to the center of the discharge. The ion beam is measurable for tens of centimeters along the expansion axis before the LIF signal fades, likely a result of metastable quenching of the beam ions. The parallel ion beam velocity slows in agreement with expectations for the measured parallel electric field. The perpendicular IVDFs show an ion population with a radially outward flow that increases with distance from the plasma axis. Structures aligned to the expanding magnetic field appear in the DC electric field, the electron temperature, and the plasma density in the plasma plume. These measurements demonstrate that at least two-dimensional and perhaps fully three-dimensional models are needed to accurately describe the spontaneous acceleration of ion beams in expanding plasmas

Numerical simulation of liquid sloshing in a partially filled container with inclusion of compressibility effects

A numerical scheme of study is developed to model compressible two-fluid flows simulating liquid sloshing in a partially filled tank. For a two-fluid system separated by an interface as in the case of sloshing, not only a Mach-uniform scheme is required, but also an effective way to eliminate unphysical numerical oscillations near the interface. By introducing a preconditioner, the governing equations expressed in terms of primitive variables are solved for both fluids (i.e. water, air, gas etc.) in a unified manner. In order to keep the interface sharp and to eliminate unphysical numerical oscillations in unsteady fluid flows, the non-conservative implicit Split Coefficient Matrix Method (SCMM) is modified to construct a flux difference splitting scheme in the dual time formulation. The proposed numerical model is evaluated by comparisons between numerical results and measured data for sloshing in an 80% filled rectangular tank excited at resonance frequency. Through similar comparisons, the investigation is further extended by examining sloshing flows excited by forced sway motions in two different rectangular tanks with 20% and 83% filling ratios. These examples demonstrate that the proposed method is suitable to capture induced free surface waves and to evaluate sloshing pressure loads acting on the tank walls and ceiling