A Virtual Engineering Framework for Simulating Advanced Power System (open access)

A Virtual Engineering Framework for Simulating Advanced Power System

In this report is described the work effort performed to provide NETL with VE-Suite based Virtual Engineering software and enhanced equipment models to support NETL's Advanced Process Engineering Co-simulation (APECS) framework for advanced power generation systems. Enhancements to the software framework facilitated an important link between APECS and the virtual engineering capabilities provided by VE-Suite (e.g., equipment and process visualization, information assimilation). Model enhancements focused on improving predictions for the performance of entrained flow coal gasifiers and important auxiliary equipment (e.g., Air Separation Units) used in coal gasification systems. In addition, a Reduced Order Model generation tool and software to provide a coupling between APECS/AspenPlus and the GE GateCycle simulation system were developed. CAPE-Open model interfaces were employed where needed. The improved simulation capability is demonstrated on selected test problems. As part of the project an Advisory Panel was formed to provide guidance on the issues on which to focus the work effort. The Advisory Panel included experts from industry and academics in gasification, CO2 capture issues, process simulation and representatives from technology developers and the electric utility industry. To optimize the benefit to NETL, REI coordinated its efforts with NETL and NETL funded projects at Iowa State University, Carnegie …
Date: June 18, 2008
Creator: Bockelie, Mike; Swensen, Dave; Denison, Martin & Borodai, Stanislav
Object Type: Report
System: The UNT Digital Library
Microwave Transmission Measurements of the Electron Cloud density In the Positron Ring of PEP-II (open access)

Microwave Transmission Measurements of the Electron Cloud density In the Positron Ring of PEP-II

Clouds of electrons in the vacuum chambers of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energy electrons clouds over substantial lengths of the beam pipe. We applied a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave which is independently excited and transmitted over a straight section of the accelerator. The modulation in the wave transmission which appears to increase in depth when the clearing solenoids are switched off, seem to be directly correlated to the electron cloud density in the section. Furthermore, we expect a larger phase shift of a wave transmitted through magnetic dipole field regionsif the transmitted wave couples with the gyration motion of the electrons. We have used this technique to measure the average electron cloud density (ECD) specifically for the first time in magnetic field regions of a new 4-dipole chicane in the positron ring of the PEP-II collider at SLAC. In this paper we present and discuss the measurements taken in the Low Energy Ring (LER) between 2006 and 2008.
Date: June 18, 2008
Creator: Pivi, Mauro T.F.; Krasnykh, Anatoly K.; Byrd, John; De Santis, Stefano; Sonnaad, Kiran G.; Caspers, Fritz et al.
Object Type: Article
System: The UNT Digital Library
The Dimensions and Number of Turns for the Tracker Solenoids As-Built compared to the Original Magnet Design (open access)

The Dimensions and Number of Turns for the Tracker Solenoids As-Built compared to the Original Magnet Design

The two tracker solenoids for MICE [1]-[3] as-built are different from the original design proposed by Wang NMR [4]. The Wang NMR design is in turn different from the magnet design proposed in the original MICE tracker magnet specification [5]. The two tracker solenoids where fabricated with niobium titanium conductor supplied to LBNL by Luvata under a specification written by LBNL [6]. This report compares the as-built tracker solenoids to the original Wang NMR design [4]. The as-built solenoid coils are thicker by 5 to 8 percent than called for the original design. This means that the current center is moved outward from 0.2 to 0.5 percent. In both tracker magnets, the thickness of end coil 2 was increased by 2-layers over the original design [5]. Thus, the current center for end coil 2 was moved outward by 0.7 percent. The number of turns per layer was underestimated in the original design from 2 to 4 percent. As a result, the current in each of the five tracker solenoid coils must be increased. In turn, the two as built tracker solenoids are compared to each other. In the ways that matter, the two tracker solenoids are nearly identical to each …
Date: June 18, 2008
Creator: Green, Michael A & Virostek, Steve P
Object Type: Report
System: The UNT Digital Library
Development of an Integrated Residential Heating, Ventilation, Cooling, and Dehumidification System for Residences (open access)

Development of an Integrated Residential Heating, Ventilation, Cooling, and Dehumidification System for Residences

The Need and the Opportunity Codes such as ASHRAE 90.2 and IECC, and programs such as Energy Star and Builders Challenge, are causing new homes to be built to higher performance standards. As a result sensible cooling loads in new homes are going down, but indoor air quality prerogatives are causing ventilation rates and moisture loads to increase in humid climates. Conventional air conditioners are unable to provide the low sensible heat ratios that are needed to efficiently cool and dehumidify homes since dehumidification potential is strongly correlated with cooling system operating hours. The project team saw an opportunity to develop a system that is at least as effective as a conventional air conditioner plus dehumidifier, removes moisture without increasing the sensible load, reduces equipment cost by integrating components, and simplifies installation. Project Overview Prime contractor Davis Energy Group led a team in developing an Integrated Heating, Ventilation, Cooling, and Dehumidification (I-HVCD) system under the DOE SBIR program. Phase I and II SBIR project activities ran from July 2003 through December 2007. Tasks included: (1) Mechanical Design and Prototyping; (2) Controls Development; (3) Laboratory and Field Testing; and (4) Commercialization Activities Technology Description. Key components of the prototype I-HVCD system …
Date: June 18, 2008
Creator: Hoeschele, M.A. & Springer, D.A.
Object Type: Report
System: The UNT Digital Library

FCV Learning Demonstration: Factors Affecting Fuel Cell Degradation

Presentation on the NREL Fuel Cell Vehicle learning demonstration prepared for the 2008 ASME Fuel Cell Conference.
Date: June 18, 2008
Creator: Kurtz, J.; Wipke, K. & Sprik, S.
Object Type: Presentation
System: The UNT Digital Library
Comment on"Elucidating the Mechanism of Nucleation near the Gas-Liquid Spinodal" (open access)

Comment on"Elucidating the Mechanism of Nucleation near the Gas-Liquid Spinodal"

In a recent Letter [1], Bhimalapuram, Chakrabarty and Bagchi (BCB) study the phase transformation mechanism of the Lennard-Jones fluid and the non-conserved Ising model. They compute the free energy as a function of the size of the largest droplet of the stable phase. In apparent contradiction to classical nucleation theory (CNT), they find that in both systems the free energy develops a minimum at subcritical cluster sizes. In this Comment we argue that this minimum is specific to the chosen order parameter, and that the observed behavior is in fact consistent with CNT. CNT states that the free energy F(N) of a single cluster of size N is a concave function with a maximum at the critical nucleus size N{sub c}. BCB, on the other hand, calculate the probability distribution of N*, the size of the largest cluster in the system, and compute the free energy {beta}F*(N*) = -ln P(N*), where {beta} = 1/k{sub B}T. This order parameter does not measure the size of a single cluster. Instead, when sampling small values of N*, one measures the statistical weight of configurations in which all clusters are at most N* in size. Hence a free energy penalty is incurred when one …
Date: June 18, 2008
Creator: Maibaum, Lutz & Maibaum, Lutz
Object Type: Article
System: The UNT Digital Library
SciDAC Computational Astrophysics Consortium (open access)

SciDAC Computational Astrophysics Consortium

Supernova explosions are the central events in nuclear astrophysics. The core-collapse variety is a major source for the universe's heavy elements. The neutron stars, pulsars, and stellar-mass black holes of high-energy astrophysics are their products. Given their prodigious explosion energies, they are the major agencies of change in the interstellar medium, driving star formation and the evolution of galaxies. Their gas remnants are the birthplaces of the cosmic rays. Such is their brightness that they can be used as standard candles to measure the size and geometry of the universe. Recently, there is evidence that gamma-ray bursts (GRBs) originate in a small fraction of core collapses, thereby connecting two of the most energetic phenomena in the universe. However, the mechanism by which core-collapse supernovae explode has not yet been unambiguously determined. Arguably, this is one of the great unsolved problems in modern astrophysics and its investigation draws on nuclear physics, particle physics, radiative transfer, kinetic theory, gravitational physics, thermodynamics, and the numerical arts. Hence, supernovae are unrivaled astrophysical laboratories. It is the quest for the mechanism and new insights our team has recently had that motivate this proposal.
Date: June 18, 2008
Creator: Burrows, Adam
Object Type: Report
System: The UNT Digital Library