The E-3 Test Facility at Stennis Space Center: Research and Development Testing for Cryogenic and Storable Propellant Combustion Systems

This paper will provide the reader a broad overview of the current upgraded capabilities of NASA's John C. Stennis Space Center E-3 Test Facility to perform testing for rocket engine combustion systems and components using liquid and gaseous oxygen, gaseous and liquid methane, gaseous hydrogen, hydrocarbon based fuels, hydrogen peroxide, high pressure water and various inert fluids. Details of propellant system capabilities will be highlighted as well as their application to recent test programs and accomplishments. Data acquisition and control, test monitoring, systems engineering and test processes will be discussed as part of the total capability of E-3 to provide affordable alternatives for subscale to full scale testing for many different requirements in the propulsion community

PEDESTRIAN PATHFINDING in URBAN ENVIRONMENTS: PRELIMINARY RESULTS

With the rise of urban population, many initiatives are focused upon the smart city concept, in which mobility of citizens arises as one of the main components. Updated and detailed spatial information of outdoor environments is needed to accurate path planning for pedestrians, especially for people with reduced mobility, in which physical barriers should be considered. This work presents a methodology to use point clouds to direct path planning. The starting point is a classified point cloud in which ground elements have been previously classified as roads, sidewalks, crosswalks, curbs and stairs. The remaining points compose the obstacle class. The methodology starts by individualizing ground elements and simplifying them into representative points, which are used as nodes in the graph creation. The region of influence of obstacles is used to refine the graph. Edges of the graph are weighted according to distance between nodes and according to their accessibility for wheelchairs. As a result, we obtain a very accurate graph representing the as-built environment. The methodology has been tested in a couple of real case studies and Dijkstra algorithm was used to pathfinding. The resulting paths represent the optimal according to motor skills and safety

Development and operation of a pixel segmented liquid-filled linear array for radiotherapy quality assurance

A liquid isooctane (C$_{8}$H$_{18}$) filled ionization linear array for radiotherapy quality assurance has been designed, built and tested. The detector consists of 128 pixels, each of them with an area of 1.7 mm $\times$ 1.7 mm and a gap of 0.5 mm. The small pixel size makes the detector ideal for high gradient beam profiles like those present in Intensity Modulated Radiation Therapy (IMRT) and radiosurgery. As read-out electronics we use the X-Ray Data Acquisition System (XDAS) with the Xchip developed by the CCLRC. Studies concerning the collection efficiency dependence on the polarization voltage and on the dose rate have been made in order to optimize the device operation. In the first tests we have studied dose rate and energy dependences, and signal reproducibility. Dose rate dependence was found lower than 2.5 % up to 5 Gy min$^{-1}$, and energy dependence lower than 2.1 % up to 20 cm depth in solid water. Output factors and penumbras for several rectangular fields have been measured with the linear array and were compared with the results obtained with a 0.125 cm$^{3}$ air ionization chamber and radiographic film, respectively. Finally, we have acquired profiles for an IMRT field and for a virtual wedge. These profiles have also been compared with radiographic film measurements. All the comparisons show a good correspondence. Signal reproducibility was within a 2% during the test period (around three months). The device has proved its capability to verify on-line therapy beams with good spatial resolution and signal to noise ratio.Comment: 16 pages, 12 figures Submitted to Phys. Med. Bio

LECTINPred: web server that uses complex networks of protein structure for prediction of lectins with potential use as cancer biomarkers or in parasite vaccine design

Ministerio de Ciencia e Innovación; AGL2010-22290-C03-01Ministerio de Ciencia e Innovación; AGL2011-30563-C03-0

Constraint-preserving boundary treatment for a harmonic formulation of the Einstein equations

We present a set of well-posed constraint-preserving boundary conditions for a first-order in time, second-order in space, harmonic formulation of the Einstein equations. The boundary conditions are tested using robust stability, linear and nonlinear waves, and are found to be both less reflective and constraint preserving than standard Sommerfeld-type boundary conditions.Comment: 18 pages, 7 figures, accepted in CQ

Improved outer boundary conditions for Einstein's field equations

In a recent article, we constructed a hierarchy B_L of outer boundary conditions for Einstein's field equations with the property that, for a spherical outer boundary, it is perfectly absorbing for linearized gravitational radiation up to a given angular momentum number L. In this article, we generalize B_2 so that it can be applied to fairly general foliations of spacetime by space-like hypersurfaces and general outer boundary shapes and further, we improve B_2 in two steps: (i) we give a local boundary condition C_2 which is perfectly absorbing including first order contributions in 2M/R of curvature corrections for quadrupolar waves (where M is the mass of the spacetime and R is a typical radius of the outer boundary) and which significantly reduces spurious reflections due to backscatter, and (ii) we give a non-local boundary condition D_2 which is exact when first order corrections in 2M/R for both curvature and backscatter are considered, for quadrupolar radiation.Comment: accepted Class. Quant. Grav. numerical relativity special issue; 17 pages and 1 figur

Efecto del manejo y del temperamento animal sobre indicadores de calidad de la carne bovina

The aim of this research was to study the effect of different handling conditions on physiological stress indicators and meat quality of beef cattle by studying animals with different temperaments. Forty animals classified by their temperament (calm and disturbed) were used. They were fed on pastures and finished with a mixed diet of corn grain and pasture. Biochemical indicators of animal stress were measured at slaughter (packed cell volume -PCV-, proteins, glucose, creatinine, alkaline phosphatase -APactivity, cortisol, insulin, glycogen). Also, ultimate pH and instrumental colour were chosen as meat quality markers. Animal temperament showed a significantly increase (p<0.05) on PCV levels and a significantly (p<0.05) decrease on muscle glycogen. Besides, levels of plasma glucose and total proteins showed significant (p<0.05) differences associated to management applied. Meat quality markers (pH and colour) did not show significant differences according to handling conditions or temperament. Mean cortisol levels at the exsanguination time were significantly higher (p<0.05) than the values obtained one week prior to slaughter, which suggests an important effect of stress associated to slaughter procedures. It would be interesting to focus attention on the assessment of acute stress at abattoir, in order to improve handling protocols, and therefore to assure meat quality in Argentinean beef production systems.El objetivo del presente trabajo fue estudiar el efecto de diferentes condiciones de manejo sobre indicadores fisiológicos de estrés y de calidad de carne en bovinos con temperamentos contrastantes. Se utilizaron cuarenta animales clasificados como calmos y excitables. Los mismos fueron alimentados inicialmente a base de pasturas y terminados con una dieta mixta de grano de maíz y pasturas. Se dosaron indicadores bioquímicos de estrés (hematocrito, proteínas plasmáticas, glucosa, creatinina, actividad fosfatasa alcalina, cortisol, insulina, contenido muscular de glucógeno). Como indicadores de calidad de carne se midieron el pH de 24 h y color instrumental. El temperamento animal demostró un incremento significativo (p<0,05) en los niveles de hematocrito y con una disminución significativa (p<0,05) del glucógeno muscular. Los niveles de glucemia y de proteínas totales mostraron modificaciones significativas (p<0,05) asociadas con el manejo. El incremento (p<0,05) en los niveles plasmáticos de cortisol durante la faena, independientemente del tratamiento o el temperamento animal, sugiere un importante efecto estresor por parte del proceso de faena. Sería interesante centrar la atención en el estudio del estrés agudo, a fin de mejorar protocolos de manejo animal, y consecuentemente, optimizar la calidad de la carne asociada en los sistemas de producción de Argentina.Fil: Pighin, D. G.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Moron; ArgentinaFil: Davies, P.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Grigioni, Gabriela Maria. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Moron; ArgentinaFil: Pazos, A. A.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Universidad de Moron; ArgentinaFil: Ceconi, I.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Mendez, Diego Eduardo. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Buffarini, M.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Sancho, A.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Universidad de Moron; ArgentinaFil: Gonzalez, Claudia Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Agroindustrias. Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Testing outer boundary treatments for the Einstein equations

Various methods of treating outer boundaries in numerical relativity are compared using a simple test problem: a Schwarzschild black hole with an outgoing gravitational wave perturbation. Numerical solutions computed using different boundary treatments are compared to a `reference' numerical solution obtained by placing the outer boundary at a very large radius. For each boundary treatment, the full solutions including constraint violations and extracted gravitational waves are compared to those of the reference solution, thereby assessing the reflections caused by the artificial boundary. These tests use a first-order generalized harmonic formulation of the Einstein equations. Constraint-preserving boundary conditions for this system are reviewed, and an improved boundary condition on the gauge degrees of freedom is presented. Alternate boundary conditions evaluated here include freezing the incoming characteristic fields, Sommerfeld boundary conditions, and the constraint-preserving boundary conditions of Kreiss and Winicour. Rather different approaches to boundary treatments, such as sponge layers and spatial compactification, are also tested. Overall the best treatment found here combines boundary conditions that preserve the constraints, freeze the Newman-Penrose scalar Psi_0, and control gauge reflections.Comment: Modified to agree with version accepted for publication in Class. Quantum Gra

A time-domain fourth-order-convergent numerical algorithm to integrate black hole perturbations in the extreme-mass-ratio limit

We obtain a fourth order accurate numerical algorithm to integrate the Zerilli and Regge-Wheeler wave equations, describing perturbations of nonrotating black holes, with source terms due to an orbiting particle. Those source terms contain the Dirac's delta and its first derivative. We also re-derive the source of the Zerilli and Regge-Wheeler equations for more convenient definitions of the waveforms, that allow direct metric reconstruction (in the Regge-Wheeler gauge).Comment: 30 pages, 12 figure