Fusion Simulation Project. Workshop Sponsored by the U.S. Department of Energy, Rockville, MD, May 16-18, 2007 (open access)

Fusion Simulation Project. Workshop Sponsored by the U.S. Department of Energy, Rockville, MD, May 16-18, 2007

The mission of the Fusion Simulation Project is to develop a predictive capability for the integrated modeling of magnetically confined plasmas. This FSP report adds to the previous activities that defined an approach to integrated modeling in magnetic fusion. These previous activities included a Fusion Energy Sciences Advisory Committee panel that was charged to study integrated simulation in 2002. The report of that panel [Journal of Fusion Energy 20, 135 (2001)] recommended the prompt initiation of a Fusion Simulation Project. In 2003, the Office of Fusion Energy Sciences formed a steering committee that developed a project vision, roadmap, and governance concepts [Journal of Fusion Energy 23, 1 (2004)]. The current FSP planning effort involved forty-six physicists, applied mathematicians and computer scientists, from twenty-one institutions, formed into four panels and a coordinating committee. These panels were constituted to consider: Status of Physics Components, Required Computational and Applied Mathematics Tools, Integration and Management of Code Components, and Project Structure and Management. The ideas, reported here, are the products of these panels, working together over several months and culminating in a three-day workshop in May 2007.
Date: May 18, 2007
Creator: Kritz, A. & Keyes, D.
Object Type: Report
System: The UNT Digital Library
Best Practices for Managing Organizational Diversity (open access)

Best Practices for Managing Organizational Diversity

In the twentieth century, ecologists and agriculturists developed an increasingly sophisticated understanding of the value of biological diversity, specifically the resilience and adaptability it brings to ecosystems. In the twenty-first century, the ecosystem model has been applied to human systems, particularly to understanding how organizations are structured and how they operate. Twenty-first century organizations are challenged by diversity in many arenas. Demographic changes in workforce composition and customer populations, combined with globalized markets and international competition are increasing the amount of diversity organizations must manage, both internally and externally. Many diversity specialists and business leaders argue that businesses and organizations interested in surviving and thriving in the twenty-first century need to take competitive advantage of a diverse workplace (Soutar, 2004; Yang, 2005). But to do so successfully, leaders and human resources (HR) managers must redefine management and leadership (Jones, 1989). Just as mono-cropping destroys biological diversity, and, in extreme cases, such as the Irish potato famine--human as well as natural ecosystems (Keohane, n.d.), so does mono-managing similarly destroy diversity within organizations. Leaders wanting to build strong, diverse organizations will not be successful if they rely on one approach or solution. Single-threaded diversity solutions, such as focusing only on recruitment or …
Date: May 18, 2007
Creator: Kreitz, Patricia A.
Object Type: Report
System: The UNT Digital Library
Charm and Charmonium Spectroscopy at B-factories (open access)

Charm and Charmonium Spectroscopy at B-factories

Since a few years, charm and charmonium spectroscopy has revived, both from experimental and theoretical point of views. Many new states have been discovered triggering numerous theoretical publications. The B-factories with their large enriched charm sample have played a leading role on the experimental side with the observation and study of most of the new states. Other experiments such as CLEO and CDF have also contributed. Classical hadron spectroscopy predicted some of these new states, but not all of them. Therefore a lot of effort have been spent in order to understand the nature of the later. We are summarizing here the most recent and important results in hadron spectroscopy, including strange-charm mesons, charm baryons and charmonium and charmonium-like states.
Date: May 18, 2007
Creator: Grenier, Philippe & /SLAC /Ecole Normale Superieure, CNRS
Object Type: Article
System: The UNT Digital Library
Status of the National Ignition Facility Integrated Computer Control System (ICCS) on the Path to Ignition (open access)

Status of the National Ignition Facility Integrated Computer Control System (ICCS) on the Path to Ignition

None
Date: May 18, 2007
Creator: Lagin, L. J.; Bettenhausen, R. C.; Bowers, G. A.; Carey, R. W.; Edwards, O. D.; Estes, C. M. et al.
Object Type: Article
System: The UNT Digital Library

Technology Validation: Fuel Cell Bus Evaluations

This presentation by Leslie Eudy at the 2007 DOE Hydrogen Program Annual Merit Review Meeting provides information about NREL's fuel cell bus evaluations.
Date: May 18, 2007
Creator: Eudy, L.
Object Type: Presentation
System: The UNT Digital Library
SuperB: A High-Luminosity Asymmetric e+e- Super Flavor Factory (open access)

SuperB: A High-Luminosity Asymmetric e+e- Super Flavor Factory

We discuss herein the exciting physics program that can be accomplished with a very large sample of heavy quark and heavy lepton decays produced in the very clean environment of an e{sup +}e{sup -} collider; a program complementary to that of an experiment such as LHCb at a hadronic machine. It then presents the conceptual design of a new type of e{sup +}e{sup -} collider that produces a nearly two-order-of-magnitude increase in luminosity over the current generation of asymmetric B Factories. The key idea is the use of low emittance beams produced in an accelerator lattice derived from the ILC Damping Ring Design, together with a new collision region, again with roots in the ILC final focus design, but with important new concepts developed in this design effort. Remarkably, SuperB produces this very large improvement in luminosity with circulating currents and wallplug power similar to those of the current B Factories. There is clear synergy with ILC R&D; design efforts have already influenced one another, and many aspects of the ILC Damping Rings and Final Focus would be operationally tested at SuperB. Finally, the design of an appropriate detector, based on an upgrade of BABAR as an example, is discussed …
Date: May 18, 2007
Creator: Bona, M. & al., /et
Object Type: Report
System: The UNT Digital Library
New Methodology For Use in Rotating Field Nuclear MagneticResonance (open access)

New Methodology For Use in Rotating Field Nuclear MagneticResonance

High-resolution NMR spectra of samples with anisotropicbroadening are simplified to their isotropic spectra by fast rotation ofthe sample at the magic angle 54.7 circ. This dissertation concerns thedevelopment of novel Nuclear Magnetic Resonance (NMR) methodologies basedwhich would rotate the magnetic field instead of the sample, rotatingfield NMR. It provides an over of the NMR concepts, procedures, andexperiments needed to understand the methodologies that will be used forrotating field NMR. A simple two-dimensional shimming method based onharmonic corrector rings which can provide arbitrary multiple ordershimming corrections were developed for rotating field systems, but couldbe used in shimming other systems as well. Those results demonstrate, forexample, that quadrupolar order shimming improves the linewidth by up toan order of magnitude. An additional order of magnitude reduction is inprinciple achievable by utilizing this shimming method for z-gradientcorrection and higher order xy gradients. A specialized pulse sequencefor the rotating field NMR experiment is under development. The pulsesequence allows for spinning away from the magic angle and spinningslower than the anisotropic broadening. This pulse sequence is acombination of the projected magic angle spinning (p-MAS) and magic angleturning (MAT) pulse sequences. This will be useful to rotating field NMRbecause there are limits on how fast a field …
Date: May 18, 2007
Creator: Jachmann, Rebecca C.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Luminosity Variations Along Bunch Trains in PEP-II (open access)

Luminosity Variations Along Bunch Trains in PEP-II

In the spring of 2005 after a long shut-down, the luminosity of the B-Factory PEP-II decreased along the bunch trains by about 25-30%. There were many reasons studied which could have caused this performance degradation, like a bigger phase transient due to an additional RF station in the Low-Energy-Ring (LER), bad initial vacuum, electron cloud, chromaticity, steering, dispersion in cavities, beam optics, etc. The initial specific luminosity of 4.2 sloped down to 3.2 and even 2.8 for a long train (typical: 130 of 144), later in the run with higher currents and shorter trains (65 of 72) the numbers were more like 3.2 down to 2.6. Finally after steering the interaction region for an unrelated reason (overheated BPM buttons) and the consequential lower luminosity for two weeks, the luminosity slope problem was mysteriously gone. Several parameters got changed and there is still some discussion about which one finally fixed the problem. Among others, likely candidates are: the LER betatron function in x at the interaction point got reduced, making the LER x stronger, dispersion reduction in the cavities, and finding and fixing a partially shorted magnet.
Date: May 18, 2007
Creator: Decker, F. J.; Boyes, M.; Colocho, W. S.; Novokhatski, A.; Sullivan, M. K.; Turner, J. L. et al.
Object Type: Article
System: The UNT Digital Library
Beta-Beat Correction Using Strong Sextupole Bumps in PEP-II (open access)

Beta-Beat Correction Using Strong Sextupole Bumps in PEP-II

A method for correcting lattice beta mismatches has been developed for the PEP-II collider using orbit offsets in strong sextupoles. The solution is first predicted in the MAD program by modeling closed orbit bumps in the plane of correction at the sextupoles strongest in that plane. The derived solution is then tested in the machine to confirm prediction, and finally dialed into the machine under high-current conditions.
Date: May 18, 2007
Creator: Yocky, G.
Object Type: Article
System: The UNT Digital Library
Tracking Down a Fast Instability in the PEP-II LER (open access)

Tracking Down a Fast Instability in the PEP-II LER

During Run 5, the beam in the PEP-II Low Energy Ring (LER) became affected by a predominantly vertical instability with very fast growth rate of 10...60/ms and varying threshold. The coherent amplitude of the oscillation was limited to approx. 1 mm peak and would damp down over a few tens of turns, however, beam loss set in even as the amplitude signal damped, causing a beam abort. This led to the conclusion that the bunches were actually blowing up. The appearance of a 2{nu}{sub S} line in the spectrum suggested a possible head-tail nature of the instability, although chromaticity was not effective in changing the threshold. The crucial hints in tracking down the cause turned out to be vacuum activity near the rf cavities and observance of signals on the cavity probes of certain rf cavities.
Date: May 18, 2007
Creator: Wienands, U.; Akre, R.; Curry, S.; DeBarger, S.; Decker, F. J.; Ecklund, S. et al.
Object Type: Article
System: The UNT Digital Library
Dimensional Duality (open access)

Dimensional Duality

We show that string theory on a compact negatively curved manifold, preserving a U(1)b1 winding symmetry, grows at least b1 new effective dimensions as the space shrinks. The winding currents yield a ''D-dual'' description of a Riemann surface of genus h in terms of its 2h dimensional Jacobian torus, perturbed by a closed string tachyon arising as a potential energy term in the worldsheet sigma model. D-branes on such negatively curved manifolds also reveal this structure, with a classical moduli space consisting of a b{sub 1}-torus. In particular, we present an AdS/CFT system which offers a non-perturbative formulation of such supercritical backgrounds. Finally, we discuss generalizations of this new string duality.
Date: May 18, 2007
Creator: Green, Daniel; Lawrence, Albion; McGreevy, John; Morrison, David R. & Silverstein, Eva
Object Type: Article
System: The UNT Digital Library
Comparing EM Models to RCS Measurements for Building-Penetration Radar (open access)

Comparing EM Models to RCS Measurements for Building-Penetration Radar

For the DARPA VisiBuilding program, SRI International and Lawrence Livermore National Laboratory are using a variety of electromagnetic (EM) simulation codes and measurement techniques to analyze how radar pulses interact with building structures and materials. Of primary interest is how interior wall and corner reflections are delayed, attenuated, and dispersed by the exterior wall materials. In this paper, we compare microwave frequency-domain radar cross section (RCS) chamber measurements of scale models of simple buildings to finite-element and finite-difference full-wave time-domain and ray-tracing models. The ability to accurately reconstruct the building from these models is compared with the reconstruction from chamber measurements. We observe that careful attention to the spatial sampling in the EM models is essential to achieving good reconstruction at the higher frequencies.
Date: May 18, 2007
Creator: Fasenfest, B & Ueberschaer, R
Object Type: Article
System: The UNT Digital Library
New Methodology For Use in Rotating Field Nuclear MagneticResonance (open access)

New Methodology For Use in Rotating Field Nuclear MagneticResonance

High-resolution NMR spectra of samples with anisotropicbroadening are simplified to their isotropic spectra by fast rotation ofthe sample at the magic angle 54.7 circ. This dissertation concerns thedevelopment of novel Nuclear Magnetic Resonance (NMR) methodologies basedwhich would rotate the magnetic field instead of the sample, rotatingfield NMR. It provides an over of the NMR concepts, procedures, andexperiments needed to understand the methodologies that will be used forrotating field NMR. A simple two-dimensional shimming method based onharmonic corrector rings which can provide arbitrary multiple ordershimming corrections were developed for rotating field systems, but couldbe used in shimming other systems as well. Those results demonstrate, forexample, that quadrupolar order shimming improves the linewidth by up toan order of magnitude. An additional order of magnitude reduction is inprinciple achievable by utilizing this shimming method for z-gradientcorrection and higher order xy gradients. A specialized pulse sequencefor the rotating field NMR experiment is under development. The pulsesequence allows for spinning away from the magic angle and spinningslower than the anisotropic broadening. This pulse sequence is acombination of the projected magic angle spinning (p-MAS) and magic angleturning (MAT) pulse sequences. This will be useful to rotating field NMRbecause there are limits on how fast a field …
Date: May 18, 2007
Creator: Jachmann, Rebecca C.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Beam-Beam Simulations for a Single Pass SuperB-Factory (open access)

Beam-Beam Simulations for a Single Pass SuperB-Factory

A study of beam-beam collisions for an asymmetric single pass SuperB-Factory is presented [1]. In this scheme an e{sup -} and an e{sup +} beam are first stored and damped in two Damping Rings (DR), then extracted, compressed and focused to the IP. After collision the two beams are re-injected in the DR to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Flat beams and round beams were compared in the simulations in order to optimize both luminosity performances and beam blowup after collision. With such approach a luminosity of the order of 10{sup 36} cm{sup -2} s{sup -1} can be achieved.
Date: May 18, 2007
Creator: Biagini, M. E.; Raimondi, P.; Seeman, J. & Schulte, D.
Object Type: Article
System: The UNT Digital Library