Space shuttle orbit maneuvering engine reusable thrust chamber program

Tests were conducted on the regenerative cooled thrust chamber of the space shuttle orbit maneuvering engine. The conditions for the tests and the durations obtained are presented. The tests demonstrated thrust chamber operation over the nominal ranges of chamber pressure mixture ratio. Variations in auxiliary film coolant flowrate were also demonstrated. High pressure tests were conducted to demonstrate the thrust chamber operation at conditions approaching the design chamber pressure for the derivative space tug application

Symplectic No-core Shell-model Approach to Intermediate-mass Nuclei

We present a microscopic description of nuclei in an intermediate-mass region, including the proximity to the proton drip line, based on a no-core shell model with a schematic many-nucleon long-range interaction with no parameter adjustments. The outcome confirms the essential role played by the symplectic symmetry to inform the interaction and the winnowing of shell-model spaces. We show that it is imperative that model spaces be expanded well beyond the current limits up through fifteen major shells to accommodate particle excitations that appear critical to highly-deformed spatial structures and the convergence of associated observables.Comment: 9 pages, 8 figure

Predicted Colors and Flux Densities of Protostars in the Herschel PACS and SPIRE Filters

Upcoming surveys with the Herschel Space Observatory will yield far-IR photometry of large samples of young stellar objects, which will require careful interpretation. We investigate the color and luminosity diagnostics based on Herschel broad-band filters to identify and discern the properties of low-mass protostars. We compute a grid of 2,016 protostars in various physical congurations, present the expected flux densities and flux density ratios for this grid of protostars, and compare Herschel observations of three protostars to the model results. These provide useful constraints on the range of colors and fluxes of protostar in the Herschel filters. We find that Herschel data alone is likely a useful diagnostic of the envelope properties of young starsComment: Part of HOPS KP papers to the Herschel special A&A issu

Information Hiding Using Convolutional Encoding

We consider two functions f1(r) and f2(r), for r 2 Rn and the problem of ‘Diffusing’ these functions together, followed by the application of an encryption process we call ‘Stochastic Diffusion’ and then hiding the output of this process in to one or other of the same functions. The coupling of these two processes (i.e., data diffusion and stochastic diffusion) is considered using a form of conditioning that generates a wellposed and data consistent inverse solution for the purpose of decrypting the output. After presenting the basic encryption method and (encrypted) information hiding model, coupled with a mathematical analysis (within the context of ‘convolutional encoding’), we provide a case study which is concerned with the implementation of the approach for full-colour 24-bit digital images. The ideas considered yields the foundations for a number of wide-ranging applications that include covert signal and image information interchange, data authentication, copyright protection and digital rights management, for example

High efficiency GaAs-Ge tandem solar cells grown by MOCVD

High conversion efficiency and low weight are obviously desirable for solar cells intended for space applications. One promising structure is GaAs on Ge. The advantages of using Ge wafers as substrates include the following: they offer high efficiency by forming a two-junction tandem cell; low weight combined with superior strength allows usage of thin (3 mil) wafers; and they are a good substrate for GaAs, being lattice matched, thermal expansion matched, and available as large-area wafers

Phase-only Digital Encryption using a Three-pass Protocol

Abstract—This paper considers an application of phase-only digital encryption to the three-pass protocol leading to a new ‘nokey- exchange algorithm’. After providing a study on the theoretical background to the method, an algorithm is presented on a step-by-step basis together with three examples of cryptanalysis. A prototype MATLAB function is provided for validation of the approach and for further development by interested readers

Young stars at large distances from the galactic plane: mechanisms of formation

We have collected from the literature a list of early-type stars, situated at large distances from the galactic plane, for which evidence of youth seems convincing. We discuss two possible formation mechanisms for these stars: ejection from the plane by dynamical interactions within small clusters, and formation away from the plane, via induced shocks created by spiral density waves. We identify the stars that could be explained by each mechanism. We conclude that the ejection mechanism can account for about two thirds of the stars, while a combination of star formation at z = 500-800 pc from the plane and ejection, can account for 90 percent of these stars. Neither mechanism, nor both together, can explain the most extreme examples.Comment: 6 pages, No figures. Sixth Pacific Rim Conference on Stellar Astrophysics - A tribute to Helmut Abt, (Kluwer