Reconstructing longitudinal strain pulses using time-resolved x-ray diffraction
Not Available
Gao, Y.↗
Engineering topics
White, S.
Publications and source records attributed to White, S..
Wide range tune scan simulations for RHIC
In this article, we report on numerical simulations to calculate dynamic apertures over wide tune ranges for RHIC. Three Blue ring lattices are used as the starting points: 2012 255 GeV polarized proton lattice, 2010 100 GeV ion run lattice, and 2012 100 GeV ion run lattice. For each lattice, we scan the fractional tunes from (0.011,0.001) to (0.991, 0.990) with a step size of 0.001 by adjusting the main arc quadrupoles QFs and QDs. The tracking results are presented, together with the resonance structures, β-beats w.r.t the base lattices, and nonlinear chromaticities.
43 PARTICLE ACCELERATORS↗
Wide range tune scan simulations for RHIC
In this article, we report on numerical simulations to calculate dynamic apertures over wide tune ranges for RHIC. Three Blue ring lattices are used as the starting points: 2012 255 GeV polarized proton lattice, 2010 100 GeV ion run lattice, and 2012 100 GeV ion run lattice. For each lattice, we scan the fractional tunes from (0.011,0.001) to (0.991, 0.990) with a step size of 0.001 by adjusting the main arc quadrupoles QFs and QDs. The tracking results are presented, together with the resonance structures, β-beats w.r.t the base lattices, and nonlinear chromaticities.
43 PARTICLE ACCELERATORS↗
Beam-beam effects in RHIC
In this article we review the beam-beam effects in the polarized proton runs in the Relativistic Heavy Ion Collider (RHIC). The operational observations, limitations, and the next luminosity goal are presented and discussed. With an upgraded polarized proton source, the proton bunch intensity will be increased from 1.7 × 10 11 up to 3.0 × 10 11 . To accommodate the large beam-beam tune spread in the current tune space between 2/3 and 7/10 and to compensate the nonlinear beam-beam resonance driving terms, head-on beam-beam compensation with electron lenses (e-lenses) is to be installed.
43 PARTICLE ACCELERATORS↗
Beam-Beam Effects in RHIC
In this article we review the beam-beam effects in the polarized proton runs in the Relativistic Heavy Ion Collider (RHIC). The operational observations, limitations, and the next luminosity goal are presented and discussed. With an upgraded polarized proton source, the proton bunch intensity will be increased from 1.7 x 10 11 up to 3.0 x 10 11 . To accommodate the large beam-beam tune spread in the current tune space between 2/3 and 7/10 and to compensate the nonlinear beam-beam resonance driving terms, head-on beam-beam compensation with electron lenses (e-lenses) is to be installed.
43 PARTICLE ACCELERATORS↗
Using the Bran Luminosity Detectors for Beam Emittance Monitoring During LHC Physics Runs
Explore the source record for details and available documents.
43 PARTICLE ACCELERATORS↗
Long-Baseline Neutrino Experiment (LBNE)
The US department of energy approved the Mission Need (CD-0) for a long baseline neu trino experiment on January 8th 2010. This marked the official start of the LBNE project whose goal is to plan and execute the construction of a next generation neutrino experiment designed to measure neutrino oscillation parameters with a neutrino beam from Fermilab detected in a large detector a mile underground in the former Homestake mine in South Dakota.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
The Long Baseline Neutrino Experiment (LBNE) Water Cherenkov Detector (WCD) Conceptual Design Report (CDR)
Conceptual Design Report developed for the Water Cherenkov Detector (WCD) option for the far detector of the Long Baseline Neutrino Experiment.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Aerogel Blanket Insulation Materials for Cryogenic Applications
Aerogel blanket materials for use in thermal insulation systems are now commercially available and implemented by industry. Prototype aerogel blanket materials were presented at the Cryogenic Engineering Conference in 1997 and by 2004 had progressed to full commercial production by Aspen Aerogels. Today, this new technology material is providing superior energy efficiencies and enabling new design approaches for more cost effective cryogenic systems. Aerogel processing technology and methods are continuing to improve, offering a tailor-able array of product formulations for many different thermal and environmental requirements. Many different varieties and combinations of aerogel blankets have been characterized using insulation test cryostats at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Detailed thermal conductivity data for a select group of materials are presented for engineering use. Heat transfer evaluations for the entire vacuum pressure range, including ambient conditions, are given. Examples of current cryogenic applications of aerogel blanket insulation are also given. KEYWORDS: Cryogenic tanks, thermal insulation, composite materials, aerogel, thermal conductivity, liquid nitrogen boil-off
Coffman, B. E.↗
Survey of Technologies Relevant to Defense From Near-Earth Objects
Several recent near-miss encounters with asteroids and comets have focused attention on the threat of a catastrophic impact with the Earth. This Technical Publication reviews the historical impact record and current understanding of the number and location of near-Earth objects (NEOs) to address their impact probability. Various ongoing projects intended to survey and catalog the NEO population are also reviewed. Details are given of a Marshall Space Flight Center-led study intended to develop and assess various candidate systems for protection of the Earth against NEOs. Details of analytical tools, trajectory tools, and a tool that was created to model both the undeflected inbound path of an NEO as well as the modified, postdeflection path are given. A representative selection of these possible options was modeled and evaluated. It is hoped that this study will raise the level of attention about this very real threat and also demonstrate that successful defense is both possible and practicable, provided appropriate steps are taken.
Adams, R. B.↗
Survey of Technologies Relevant to Defense From Near-Earth Objects
Several recent near-miss encounters with asteroids and comets have focused attention on the threat of a catastrophic impact with the Earth. This Technical Publication reviews the historical impact record and current understanding of the number and location of near-Earth objects (NEOs) to address their impact probability. Various ongoing projects intended to survey and catalog the NEO population are also reviewed. Details are given of a Marshall Space Right Center-led study intended to develop and assess various candidate systems for protection of the Earth against NEOs. Details of analytical tools, trajectory tools, and a tool that was created to model both the undeflected inbound path of an NEO as well as the modified, post-deflection path are given. A representative selection of these possible options was modeled and evaluated. It is hoped that this study will raise the level of attention about this very real threat and also demonstrate that successful defense is both possible and practicable, provided appropriate steps are taken.
Adams, R. B.↗
Engineering of the Magnetized Target Fusion Propulsion System
Engineering details are presented for a magnetized target fusion (MTF) propulsion system designed to support crewed missions to the outer solar system. Basic operation of an MTF propulsion system is introduced. Structural, thermal, radiation-management and electrical design details are presented. The propellant storage and supply system design is also presented. A propulsion system mass estimate and associated performance figures are given. The advantages of helium-3 as a fusion fuel for an advanced MTF system are discussed.
Statham, G.↗
Crewed Mission to Callisto Using Advanced Plasma Propulsion Systems
This paper describes the engineering of several vehicles designed for a crewed mission to the Jovian satellite Callisto. Each subsystem is discussed in detail. Mission and trajectory analysis for each mission concept is described. Crew support components are also described. Vehicles were developed using both fission powered magneto plasma dynamic (MPD) thrusters and magnetized target fusion (MTF) propulsion systems. Conclusions were drawn regarding the usefulness of these propulsion systems for crewed exploration of the outer solar system.
Adams, R. B.↗
Engineering of the Magnetized Target Fusion Propulsion System
Engineering details are presented for a magnetized target fusion (MTF) propulsion system designed to support crewed missions to the outer solar system. Structural, thermal and radiation-management design details are presented. Propellant storage and supply options are also discussed and a propulsion system mass estimate is given.
Statham, G.↗
The CHANDRA HETGS X-ray Grating Spectrum of Eta Carinae
Eta Carinae may be the most massive and luminous star in the Galaxy and is suspected to be a massive, colliding wind binary system. The CHANDRA X-ray observatory has obtained a calibrated, high-resolution X-ray spectrum of the star uncontaminated by the nearby extended soft X-ray emission. Our 89 ksec CHANDRA observation with the High Energy Transmission Grating Spectrometer (HETGS) shows that the hot gas near the star is non-isothermal. The temperature distribution may represent the emission on either side of the colliding wind bow shock, effectively 'resolving' the shock. If so, the pre-shock wind velocities are approximately 700 and 1800 km/s in our analysis, and these velocities may be interpreted as the terminal velocities of the winds from 71 Carinae and from the hidden companion star. The forbidden-to-intercombination line ratios for the He-like ions of S, Si, and Fe are large, indicating that the line forming region lies far from the stellar photosphere. The iron fluorescent line at 1.93 angstroms, first detected by ASCA, is clearly resolved from the thermal iron line in the CHANDRA grating spectrum. The Fe fluorescent line is weaker in our CHANDRA observation than in any of the ASCA spectra. The CHANDRA observation also provides the first high-time resolution lightcurve of the uncontaminated stellar X-ray emission from 77 Carinae and shows that there is no significant, coherent variability during the CHANDRA observation. The 77 Carinae CHANDRA grating spectrum is unlike recently published X-ray grating spectra of single massive stars in significant ways and is generally consistent with colliding wind emission in a massive binary.
Corcoran, M. F.↗
Recurrent X-ray Emission Variations of Eta Carinae and the Binary Hypothesis
Recent studies suggest that, the super-massive star eta Carinae may have a massive stellar companion (Damineli, Conti, and Lopes 1997), although the dense ejecta surrounding the star make this claim hard to test using conventional methods. Settling this question is critical for determining the current evolutionary state and future evolution of the star. We address this problem by an unconventional method: If eta Carinae is a binary, X-ray emission should be produced in shock waves generated by wind-wind collisions in the region between eta Carinae and its companion. Detailed X-ray monitoring of eta Carinae for more that) 2 years shows that the observed emission generally resembles colliding-wind X-ray emission, but with some significant discrepancies. Furthermore, periodic X-ray "flaring" may provide an additional clue to determine the presence of a companion star and for atmospheric pulsation in eta Carinae.
Ishibashi, K.↗
Flow and heat transfer in space vehicle tile gaps
The flow patterns and the characteristics of the convective heat transfer in intersecting tile gaps on space vehicles were experimentally investigated using a water channel flow facility for simulating flow conditions in the tile gaps on the Aeroassist Flight Experiment (AFE) vehicle. It was found that penetration of external flow into the perpendicular gap was limited in most cases to roughly two gap widths, while greater entrainment occurred in the parallel gap. Heat transfer in the bulk of the perpendicular gap occurred by natural convection. The Reynolds number and the relative tile-height differences had the strongest influence on heat transfer and affected both the magnitude and the symmetry of the temperature and the flow fields.
Garimella, S. V.↗
A unified approach for numerical simulation of viscous compressible and incompressible flows over adiabatic and isothermal walls
A new formulation (including the choice of variables, their non-dimensionalization, and the form of the artificial viscosity) is proposed for the numerical solution of the full Navier-Stokes equations for compressible and incompressible flows with heat transfer. With the present approach, the same code can be used for constant as well as variable density flows. The changes of the density due to pressure and temperature variations are identified and it is shown that the low Mach number approximation is a special case. At zero Mach number, the density changes due to the temperature variation are accounted for, mainly through a body force term in the momentum equation. It is also shown that the Boussinesq approximation of the buoyancy effects in an incompressible flow is a special case. To demonstrate the new capability, three examples are tested. Flows in driven cavities with adiabatic and isothermal walls are simulated with the same code as well as incompressible and supersonic flows over a wall with and without a groove. Finally, viscous flow simulations of an oblique shock reflection from a flat plate are shown to be in good agreement with the solutions available in literature.
Hafez, M.↗