General MoM Solutions for Large Arrays (open access)

General MoM Solutions for Large Arrays

This paper focuses on a numerical procedure that addresses the difficulties of dealing with large, finite arrays while preserving the generality and robustness of full-wave methods. We present a fast method based on approximating interactions between sufficiently separated array elements via a relatively coarse interpolation of the Green's function on a uniform grid commensurate with the array's periodicity. The interaction between the basis and testing functions is reduced to a three-stage process. The first stage is a projection of standard (e.g., RWG) subdomain bases onto a set of interpolation functions that interpolate the Green's function on the array face. This projection, which is used in a matrix/vector product for each array cell in an iterative solution process, need only be carried out once for a single cell and results in a low-rank matrix. An intermediate stage matrix/vector product computation involving the uniformly sampled Green's function is of convolutional form in the lateral (transverse) directions so that a 2D FFT may be used. The final stage is a third matrix/vector product computation involving a matrix resulting from projecting testing functions onto the Green's function interpolation functions; the low-rank matrix is either identical to (using Galerkin's method) or similar to that for …
Date: July 22, 2003
Creator: Fasenfest, B; Capolino, F; Wilton, D R; Jackson, D R & Champagne, N
Object Type: Article
System: The UNT Digital Library
Growth and characterization of In{sub x}Ga{sub 1-x}N MQW using a novel method of temperature gradient OMVPE (open access)

Growth and characterization of In{sub x}Ga{sub 1-x}N MQW using a novel method of temperature gradient OMVPE

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Date: July 22, 2003
Creator: Johnson, M.C.; Jorgensen, R.J.; Wu, J.; Shan, W. & Bourret-Courchesne, E.
Object Type: Article
System: The UNT Digital Library
Treated LAW Feed Evaporation: Physical and Solubility Determination (U) (open access)

Treated LAW Feed Evaporation: Physical and Solubility Determination (U)

Evaporation is employed in several places in the Waste Treatment Plant pretreatment process to minimize the volume of waste that must be treated in down-stream vitrification processes. Evaporation is the first unit process in pretreatment (Waste Feed Evaporators), applied before LAW vitrification (Treated Feed Evaporator), and concentrates ion exchange eluate (Cs Eluate Evaporator) prior to HLW vitrification. The goal of the Treated Feed Evaporation process is removal of the maximum water content without producing additional insoluble solids. Prior testing of evaporation systems for process feed was completed to support compliance with regulatory permits and to prepare a model of the evaporation system. These tests also indicated a marked tendency for foaming in the WTP evaporators. To date, evaporation testing and modeling have focused on the Treated feed and Cs eluate evaporation systems. This has been the first work performed that investigates evaporation of secondary-waste recycle streams in the Treated LAW Feed Evaporator. Secondary-waste recycles from the LAW off- gas scrubbing system have been the major contributors to the overall Treated Feed Evaporator recycle volume. Experience from Savannah River Site operations suggests that the introduction of silica- laden recycles to an evaporator along with high-sodium treated LAW can significantly increase the …
Date: July 22, 2003
Creator: Josephs, JE.
Object Type: Report
System: The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT (open access)

EARLY ENTRANCE COPRODUCTION PLANT

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The object of phase 1 is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD and T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase 2 is to implement the work as outlined in the Phase 1 RD and T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase 3 is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site.
Date: July 22, 2003
Creator: Ho, Chi M.; Battista, Robert A.; Anand, Ashok & Yackly, Kenneth
Object Type: Report
System: The UNT Digital Library
Lattice Boltzmann Simulation of Particle Laden Flows in Microfluidic Systems (open access)

Lattice Boltzmann Simulation of Particle Laden Flows in Microfluidic Systems

The goal of this effort was to develop dynamic simulation tools to study and characterize particulate transport in Microfluidic devices. This includes the effects of external fields and near-field particle-particle, particle-surface interactions. The unique aspect of this effort is that we focused on the particles in suspension and rigorously accounted for all of the interactions that they experienced in solution. In contrast, other numerical methods within the program, finite element and finite volume approaches, typically treat the suspended species as non-interacting point particles. Later in the program, some of these approaches incorporated approximations to begin to account for particle-particle interactions. Through the programs (BioFlips and SIMBIOSYS), we developed collaborative relationships with device-oriented efforts. More specifically and at the request of the SIMBIOSYS program manager, we allowed our efforts/milestones to be more guided by the needs of our BioFlips colleagues; therefore, our efforts were focused on the needs of the MD Anderson Cancer Center (Peter Gascoyne), UCDavis (Rosemary Smith), and UC Berkeley (Dorian Liepmann). The first two collaborations involved the development of Dielectrophoresis analysis tools and the later involved the development of suspension and fluid modeling tools for microneedles.
Date: July 22, 2003
Creator: Clague, D. S.; Weisgraber, T.; Wheeler, E.; Hon, G.; Radford, J.; Gascoyne, P. et al.
Object Type: Report
System: The UNT Digital Library
Quantum-Shell Corrections to the Finite-Temperature Thomas-Fermi-Dirac Statistical Model of the Atom (open access)

Quantum-Shell Corrections to the Finite-Temperature Thomas-Fermi-Dirac Statistical Model of the Atom

Quantum-shell corrections are made directly to the finite-temperature Thomas-Fermi-Dirac statistical model of the atom by a partition of the electronic density into bound and free components. The bound component is calculated using analytic basis functions whose parameters are chosen to minimize the energy. Poisson's equation is solved for the modified density, thereby avoiding the need to solve Schroedinger's equation for a self-consistent field. The shock Hugoniot is calculated for aluminum: shell effects characteristic of quantum self-consistent field models are fully captures by the present model.
Date: July 22, 2003
Creator: Ritchie, A. B.
Object Type: Report
System: The UNT Digital Library
Enhanced Practical Photosynthetic CO2 Mitigation (open access)

Enhanced Practical Photosynthetic CO2 Mitigation

This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 4/2/2003 through 7/01/2003. As indicated in the list of accomplishments below we have completed some long-term model scale bioreactor tests and are prepared to begin pilot scale bioreactor testing. Specific results and accomplishments for the second quarter of 2003 include: (1) Bioreactor support systems and test facilities: (a) Qualitative long-term survivability tests for S.C.1.2(2) on Omnisil have been successfully completed and results demonstrate a growth rate that appears to be acceptable. (b) Quantitative tests of long-term growth productivity for S.C.1.2(2) on Omnisil have been completed and initial results are promising. Initial results show that the mass of organisms doubled (from 54.9 grams to 109.8 grams) in about 5 weeks. Full results will be available as soon as all membranes and filters are completely dried. The growth rate should increase significantly with the initiation of weekly harvesting during the long term tests. (c) The phase 1 construction of the pilot scale bioreactor has been completed, including the solar collector and light distribution system. We are now in the phase of system improvement as we wait for CRF-2 results in order to be …
Date: July 22, 2003
Creator: Kremer, Gregory; Bayless, David J.; Vis, Morgan; Prudich, Michael; Cooksey, Keith & Muhs, Jeff
Object Type: Report
System: The UNT Digital Library
Fresnel Integral Equations: Numerical Properties (open access)

Fresnel Integral Equations: Numerical Properties

A spatial-domain solution to the problem of electromagnetic scattering from a dielectric half-space is outlined. The resulting half-space operators are referred to as Fresnel surface integral operators. When used as preconditioners for nonplanar geometries, the Fresnel operators yield surface Fresnel integral equations (FIEs) which are stable with respect to dielectric constant, discretization, and frequency. Numerical properties of the formulations are discussed.
Date: July 22, 2003
Creator: Adams, R. J.; Champagne, N. J., II & Davis, B. A.
Object Type: Article
System: The UNT Digital Library