Process for the leaching of AP from propellant

A method for the recovery of ammonium perchlorate from waste solid rocket propellant is described wherein shredded particles of the propellant are leached with an aqueous leach solution containing a low concentration of surface active agent while stirring the suspension

Testing the Modern Merger Hypothesis via the Assembly of Massive Blue Elliptical Galaxies in the Local Universe

The modern merger hypothesis offers a method of forming a new elliptical galaxy through merging two equal-mass, gas-rich disk galaxies fuelling a nuclear starburst followed by efficient quenching and dynamical stabilization. A key prediction of this scenario is a central concentration of young stars during the brief phase of morphological transformation from highly-disturbed remnant to new elliptical galaxy. To test this aspect of the merger hypothesis, we use integral field spectroscopy to track the stellar Balmer absorption and 4000\AA\ break strength indices as a function of galactic radius for 12 massive (${\rm M_{*}}\ge10^{10}{\rm M_{\odot}}$), nearby (${\rm z}\le0.03$), visually-selected plausible new ellipticals with blue-cloud optical colours and varying degrees of morphological peculiarities. We find that these index values and their radial dependence correlate with specific morphological features such that the most disturbed galaxies have the smallest 4000\AA\ break strengths and the largest Balmer absorption values. Overall, two-thirds of our sample are inconsistent with the predictions of the modern merger hypothesis. Of these eight, half exhibit signatures consistent with recent minor merger interactions. The other half have star formation histories similar to local, quiescent early-type galaxies. Of the remaining four galaxies, three have the strong morphological disturbances and star-forming optical colours consistent with being remnants of recent, gas-rich major mergers, but exhibit a weak, central burst consistent with forming $\sim5\%$ of their stars. The final galaxy possesses spectroscopic signatures of a strong, centrally-concentrated starburst and quiescent core optical colours indicative of recent quenching (i.e., a post-starburst signature) as prescribed by the modern merger hypothesis.Comment: 25 pages, 37 figures, accepted to MNRA

Solar Atmospheric Oscillations and the Chromospheric Magnetic Topology

We investigate the oscillatory properties of the quiet solar chromosphere in relation to the underlying photosphere, with particular regard to the effects of the magnetic topology. We perform a Fourier analysis on a sequence of line-of-sight velocities measured simultaneously in a photospheric (Fe I 709.0 nm) and a chromospheric line (Ca II 854.2 nm). The velocities were obtained from full spectroscopic data acquired at high spatial resolution with the Interferometric BIdimensional Spectrometer (IBIS). The field of view encompasses a full supergranular cell, allowing us to discriminate between areas with different magnetic characteristics. We show that waves with frequencies above the acoustic cut-off propagate from the photosphere to upper layers only in restricted areas of the quiet Sun. A large fraction of the quiet chromosphere is in fact occupied by ``magnetic shadows'', surrounding network regions, that we identify as originating from fibril-like structures observed in the core intensity of the Ca II line. We show that a large fraction of the chromospheric acoustic power at frequencies below the acoustic cut-off, residing in the proximity of the magnetic network elements, directly propagates from the underlying photosphere. This supports recent results arguing that network magnetic elements can channel low-frequency photospheric oscillations into the chromosphere, thus providing a way to input mechanical energy in the upper layers.Comment: 4 pages, 3 figure, A&A Letters in pres

Coronal emission lines as thermometers

Coronal emission line intensities are commonly used to measure electron temperatures using emission measure and/or line ratio methods. In the presence of systematic errors in atomic excitation calculations and data noise, the information on underlying temperature distributions is fundamentally limited. Increasing the number of emission lines used does not necessarily improve the ability to discriminate between different kinds of temperature distributions.Comment: Accepted by ApJ, November 200

Twisting type-N vacuum fields with a group H2H_2

We derive the equations corresponding to twisting type-N vacuum gravitational fields with one Killing vector and one homothetic Killing vector by using the same approach as that developed by one of us in order to treat the case with two non-commuting Killing vectors. We study the case when the homothetic parameter $\phi$ takes the value -1, which is shown to admit a reduction to a third-order real ordinary differential equation for this problem, similar to that previously obtained by one of us when two Killing vectors are present.Comment: LaTeX, 11 pages. To be published in Classical and Quantum Gravit

Academic tutors/advisors and students working in partnership: negotiating and co-creating in “The Third Space”

In this perspectives piece, we argue that technology can be used to create and facilitate “Third Space” advising, via a model of “flipped advising” which focuses on the development of quality staff–student partnerships. “Third Space” advising, using technology, encourages students and staff to work together to create and validate knowledge, connect experiences, and improve the learning culture of the organization. It also aligns with Hockings’ (2010) definition of inclusive practice in learning and teaching. While so much focus has been on the development of the advisor, the concept of Students as Partners (SaP) and “The Third Space” offer important lenses within which to shift the focus of advising practice away from the development of advisors and toward the development of staff–student partnerships, with a view to improving the impact and outcomes on students themselves

Magnetic suspension and balance system advanced study

An improved compact design for a superconducting magnetic suspension and balance system for an 8 ft. x 8 ft. transonic wind tunnel is developed. The original design of an MSBS in NASA Cr-3802 utilized 14 external superconductive coils and a superconductive solenoid in the airplane test model suspended in a wind tunnel. The improvements are in the following areas: test model solenoid options, dynamic force limits on the model, magnet cooling options, structure and cryogenic designs, power supply specifications, and cost and performance evaluations. The improvements are: MSBS cost reduction of 28%, weight; reduction of 43%, magnet system ampere-meter reduction of 38%, helium liquifier capacity reduction by 33%, magnet system stored energy reduction by 55%, AC loss to liquid helium reduced by 76%, system power supply reduced by 68%, test coil pole strength increased by 19%, wing magnetization increased by 40%, and control frequency limit increased by 200% from 10 Hz to 30 Hz. The improvements are due to: magnetic holmium coil forms in the test model, better rare earth permanent magnets in the wings, fiberglass-epoxy structure replacing stainless steel, better coil configuration, and new saddle roll coil design

Repulsive force support system feasibility study

A new concept in magnetic levitation and control is introduced for levitation above a plane. A set of five vertical solenoid magnets mounted flush below the plane supports and controls the model in five degrees of freedom. The compact system of levitation coils is contained in a space 2.4 m (96 in) diameter by 1 m (40 in) deep with the top of the levitation system 0.9 m (36 in) below the center line of the suspended model. The levitated model has a permanent magnet core held in position by the five parallel superconductive solenoids symmetrically located in a circle. The control and positioning system continuously corrects for model position in five dimensions using computer current pulses superimposed on the levitation coil base currents. The conceptual designs include: superconductive and Nd-Fe-B permanent magnet model cores and levitation solenoids of either superconductive, cryoresistive, or room temperature windings