Development of Novel, Simple Multianalyte Sensors for Remote Environmental Analysis (open access)

Development of Novel, Simple Multianalyte Sensors for Remote Environmental Analysis

Advancement of our polymerized crystalline colloidal array chemical sensing technology. They have dramatically advanced their polymerized crystalline colloidal array chemical sensing technology. They fabricated nonselective sensors for determining pH and ionic strength. They also developed selective sensors for glucose and organophosphorus mimics of nerve gas agents. They developed a trace sensor for cations in water which utilized a novel crosslinking sensing motif. In all of these cases they have been able to theoretically model their sensor response by extending hydrogel volume phase transition theory. They also developed transient sampling methods to allow their ion sensing methods to operate at high ionic strengths. They also developed a novel optrode to provide for simple sampling.
Date: February 18, 2003
Creator: Asher, Sanford A.
System: The UNT Digital Library
Non-existence of Normal Tokamak Equilibria with Negative Central Current (open access)

Non-existence of Normal Tokamak Equilibria with Negative Central Current

Recent tokamak experiments employing off-axis, non-inductive current drive have found that a large central current hole can be produced. The current density is measured to be approximately zero in this region, though in principle there was sufficient current-drive power for the central current density to have gone significantly negative. Recent papers have used a large aspect-ratio expansion to show that normal MHD equilibria (with axisymmetric nested flux surfaces, non-singular fields, and monotonic peaked pressure profiles) can not exist with negative central current. We extend that proof here to arbitrary aspect ratio, using a variant of the virial theorem to derive a relatively simple integral constraint on the equilibrium. However, this constraint does not, by itself, exclude equilibria with non-nested flux surfaces, or equilibria with singular fields and/or hollow pressure profiles that may be spontaneously generated.
Date: February 18, 2003
Creator: Hammett, G. W.; Jardin, S. C. & Stratton, B. C.
System: The UNT Digital Library
Analysis of AGS polarimeter data at G{gamma}=7.5. (open access)

Analysis of AGS polarimeter data at G{gamma}=7.5.

Data were collected with the AGS internal polarimeter at G{gamma} = 7.5 during the recent FY02 polarized proton run. The addition of new forward scintillation counters permitted an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized, and the polarization measured at G{gamma} = 7.5 is compared to that at 200 MeV.
Date: February 18, 2003
Creator: Huang, H.; Cadman, R. V.; Spinka, H. M. & Underwood, D. G.
System: The UNT Digital Library
Feed Basis for Processing Relatively Low Radioactivity Waste Tanks (open access)

Feed Basis for Processing Relatively Low Radioactivity Waste Tanks

This paper presents the characterization of potential feed for processing relatively low radioactive waste tanks. The feed characterization is based on waste characterization data extracted from the waste characterization system. This data is compared to salt cake sample results from Tanks 37, 38, and 41.
Date: February 18, 2003
Creator: Jones (contact), R.T.
System: The UNT Digital Library
Saltcake Dissolution Simulant Tests (open access)

Saltcake Dissolution Simulant Tests

Small-scale (15 to 50 mL) dissolution equilibrium tests were performed on surrogate waste representing typical saltcake at the Savannah River and Hanford Sites. The primary objectives of this study were to gain a better understanding of the solid-liquid equilibrium of simulated-waste saltcakes and chemistry of the dissolved salt solutions. These tests were performed in preparation for similar dissolution tests with actual-waste saltcakes. Two types of tests (single-wash and multiple-wash) were performed at two temperatures (25 degrees Celsius and 50 degrees Celsius) for each saltcake simulant. The compositions of the supernatant fluids are provided for both types of dissolution tests, and profiles of the elution of each salt component are provided for the multiple-wash tests. The conclusions from these tests follow: (1) For both salt waste surrogates, dissolution of the soluble components was achieved at less than a 2:1 mass ratio of inhibited water to saltcake during multiple-wash tests., (2) Dissolution of the Hanford S-112 simulant resulted in a relatively large weight percentage of residual insoluble material (4.2 wt. percent), which was identified as a mixture of Al(OH)3 phases (bayerite and gibbsite)., and (3) The profiles for the relative elution of anions from saltcake during dissolution exhibit distinctions that are dependent …
Date: February 18, 2003
Creator: Martino, C.J.
System: The UNT Digital Library
On the Performance of Parallel Algebraic Multigrid (open access)

On the Performance of Parallel Algebraic Multigrid

As algebraic multigrid (AMG) can be applied to a wide variety of problems on extremely large, unstructured grids on the one hand and massively parallel computer systems are available on the other hand, there has been a need for parallel implementations of AMG. This report analyses the performance of BoomerAMG[1], a parallel algorithm developed at Lawrence Livermore National Laboratory. Abstracting the implementation we describe the basic components of the costly setup phase and analyze their behavior in a (massively) parallel distributed memory environment. We present numerical results, compare them to the developed theory and finally aim at possible improvements in the future.
Date: February 18, 2003
Creator: Naegel, Arne & Falgout, Robert
System: The UNT Digital Library
LDRD Report FY 03: Structure and Function of Regulatory DNA: A Next Major Challenge in Genomics (open access)

LDRD Report FY 03: Structure and Function of Regulatory DNA: A Next Major Challenge in Genomics

With the human genome sequence now available and high quality draft sequences of mouse, rat and many other creatures recently or soon to be released, the field of Genomics has entered an especially exciting phase. The raw materials for locating the {approx}30-40,000 human genes and understanding their basic structure are now online; next, the research community must begin to unravel the mechanisms through which those genes create the complexity of life. Laboratories around the world are already beginning to focus on cataloguing the times, sites and conditions under which each gene is active; others are racing to predict, and then experimentally analyze, the structures of proteins that human genes encode. These activities are extremely important, but they will not reveal the mechanisms through which the correct proteins are activated precisely in the specific cells and at the particular time that is required for normal developmental, health, and in response to the environment. Although we understand well the three-letter code through which genes dictate the production of proteins, the codes through which genes are turned on and off in precise, cell-specific patterns remain a mystery. Unraveling these codes are essential to understanding the functions of genes and the role of human …
Date: February 18, 2003
Creator: Stubbs, L
System: The UNT Digital Library