Computational analysis and design of an aerofoil with morphing tail for improved aerodynamic performance in transonic regime

This article focuses on the aerodynamic design of a morphing aerofoil at cruise conditions using computational fluid dynamics (CFD). The morphing aerofoil has been analysed at a Mach number of 0.8 and Reynolds number of $3 \times 10^{6}$ , which represents the transonic cruise speed of a commercial aircraft. In this research, the NACA0012 aerofoil has been identified as the baseline aerofoil where the analysis has been performed under steady conditions at a range of angles of attack between $0^{^{\kern1pt\circ}}$ and $3.86^{^{\kern1pt\circ}}$ . The performance of the baseline case has been compared to the morphing aerofoil for different morphing deflections ( $w_{te}/c = [0.005 - 0.1]$ ) and start of the morphing locations ( $x_{s}/c = [0.65 - 0.80]$ ). Further, the location of the shock wave on the upper surface has also been investigated due to concerns about the structural integrity of the morphing part of the aerofoil. Based upon this investigation, a most favourable morphed geometry has been presented that offers both, a significant increase in the lift-to-drag ratio against its un-morphed counterpart and has a shock location upstream of the start of the morphing part.

Limited evidence for learning in a shuttle box paradigm in crickets (Acheta domesticus)

Aversive learning has been studied in a variety of species, such as honey bees, mice, and non-human primates. Since aversive learning has been found in some invertebrates and mammals, it will be interesting to know if this ability is shared with crickets. This paper provides data on aversive learning in male and female house crickets (Acheta domesticus) using a shuttle box apparatus. Crickets are an ideal subject for these experiments due to their well-documented learning abilities in other contexts and their readily quantifiable behaviors. The shuttle box involves a two-compartment shock grid in which a ‘master’ cricket can learn to avoid the shock by moving to specific designated locations, while a paired yoked cricket is shocked regardless of its location and therefore cannot learn. Baseline control crickets were placed in the same device as the experimental crickets but did not receive a shock. Male and female master crickets demonstrated some aversive learning, as indicated by spending more time than expected by chance in the correct (no shock) location during some parts of the experiment, although there was high variability in performance. These results suggest that there is limited evidence that the house crickets in this experiment learned how to avoid the shock. Further research with additional stimuli and other cricket species should be conducted to determine if house crickets and other species of crickets exhibit aversive learning.

Estimating Ion Escape from Unmagnetized Planets

We propose a new method to estimate ion escape from unmagnetized planets that combines observations and models. Assuming that upstream solar wind conditions are known, a computer model of the interaction between the solar wind and the planet is executed for different ionospheric ion production rates. This results in different amounts of mass loading of the solar wind. Then we obtain the ion escape rate from the model run that best fit observations of the bow shock location. As an example of the method we estimate the heavy ion escape from Mars on 2015-03-01 to be 2 · 1024 ions per second, using a hybrid plasma model and observations by MAVEN and Mars Express. This method enables studies of how escape depend on different parameters, and also escape rates during extreme solar wind conditions, applicable to studies of escape in the early solar system, and at exoplanets.

Dynamics of the Martian bow shock location

<p>The Martian interaction with the solar wind is unique due to the influence of multiple internal and external drivers, including remanent crustal magnetic fields that make the interaction unique. In this work we focus on the analysis of the dynamics of the plasma boundaries that shape the interaction of the planet with its environment, and in particular of the shock whose location varies in a complex way. We use multi spacecraft datasets from three missions (Mars Global Surveyor, Mars Express, Mars Atm-osphere and Volatile Evolution) to provide a coherent picture of the shock drivers. We show how the use of different statistical parameters or cross correlations may modify conclusions. We thus propose the use of refined methods, such as partial correlation analysis or Akaike Information Criterion approach to analyse the multiple drivers of the shock location and rank their relative importance: solar wind dynamic pressure, extreme ultraviolet fluxes, magnetosonic mach number, crustal magnetic fields, but also solar wind orientation parameters. Seasonal effects of crustal fields on the shock, through ionospheric coupling, are also investigated.</p>

3-D Axisymmetric Transonic Shock Solutions of the Full Euler System in Divergent Nozzles

We establish the stability of 3-D axisymmetric transonic shock solutions of the steady full Euler system in divergent nozzles under small perturbations of an incoming radial supersonic flow and a constant pressure at the exit of the nozzles. To study 3-D axisymmetric transonic shock solutions of the full Euler system, we use a stream function formulation of the full Euler system for a 3-D axisymmetric flow. We resolve the singularity issue arising in stream function formulations of the full Euler system for a 3-D axisymmetric flow. We develop a new scheme to determine a shock location of a transonic shock solution of the steady full Euler system based on the stream function formulation.

PRIMORYE EARTHQUAKE on April 12, 2014, KP=11.9 (Far Eastern Russia)

The article presents instrumental and macroseismic data of the earthquake that occurred on April 12, 2014 in the Primorye Region of the Far Eastern Federal District of the Russian Federation. Primorye refers to areas with a weak of shallow seismic activity. This relatively small magnitude M=4.5 earthquake is a rare occurrence in this region. It caused a significant macroseismic effect over an unexpectedly large area. The highest seismic intensity as large as 5 degrees was observed in the settlements nearest to the epicenter – Mezhgorye, Krylovka and Maryanovka. 36 minutes after the main event, an aftershock was recorded with an epicenter 6.5 km southeast of the main shock location, felt by the inhabitants of the settlement of Krylovka. According to the data obtained, the focal mechanism of the earthquake might be treated as the strikeslip fault type with the nodal planes of the sublatitudinal and sublongitudinal extension. In view of tectonics, the earthquake and its aftershock epicenters might be related to a nameless NW striking fault located near Mezhgorye Settlement and linking the Krylovsky and Chernorechensky faults.

Electric current systems at Mars and Venus

<p>The physics of the interaction of unmagnetized planets with the Solar wind has<br />been investigated since the first Mariner spacecraft did reach Mars and Venus<br />more than 50 years ago. Recent observations of the magnetic fields at Mars allowed <br />to derive the global electric current configuration in the Martian system.<br />Earlier magneto hydro-dynamic models were able to predict the formation<br />and location of the bowshock in front of the planets. More sophisticated models <br />of the interaction with the magnetized solar wind later could demonstrate<br />the global static picture of the plasma environment of Mars and Venus. But earlier models were rarely<br />able to model dynamic effects and the timing of physical process in this interaction.<br />We here use the open source PLUTO code in its 3D spherical hydrodynamic and magneto-hydrodynamic version. <br />We also develop a multi-species extension of this code. <br />We investigate the interaction of the solar wind with the ionospheres of Mars and Venus with the aim to understand the <br />importance of  different physical effects on bow shock location, ion escape and specifically the electric current structures. <br />We compare these simulations to observations by the VEX and MAVEN spacecraft.</p>