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The characterization of atmospheric aerosols: Application to heterogeneous gas-particle reactions

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project of the Los Alamos National Laboratory (LANL). The objective of this collaborative research project is the measurement and modeling of atmospheric aerosols and heterogeneous (gas/aerosol) chemical reactions. The two major accomplishments are single particle characterization of tropospheric particles and experimental investigation of simulated stratospheric particles and reactions thereon. Using aerosol time-of-flight mass spectrometry, real-time and composition measurements of single particles are performed on ambient aerosol samples. This technique allows particle size distributions for chemically distinct particle types to be described. The thermodynamics and chemical reactivity of polar stratospheric clouds are examined using vapor deposited thin ice films. Employing nonlinear optical methods, as well as other techniques, phase transitions on both water and acid ices are monitored as a function of temperature or the addition of gases.
Date: December 31, 1998
Creator: Robinson, J.M.; Henson, B.F.; Wilson, K.R.; Prather, K.A. & Noble, C.A.

Characterization of beam position monitors for measurement of second moment

Description: A dual-axis beam position monitor (BPM) consists of four electrodes placed at 90{degree} intervals around the probe aperture. The response signals of these lobes can be expressed as a sum of moments. The first order moment gives the centroid of the beam. The second order moment contains information about the rms size of the beam. It has been shown previously that the second order moment can be used to determine beam emittance. To make this measurement, the authors must characterize the BPM appropriately. The approach to this problem is to use a pulsed wire test fixture. By using the principle of superposition, they can build up a diffuse beam by taking the signals from different wire positions and summing them. This is done two ways: first by physically moving a wire about the aperture and building individual distributions, and, second, by taking a two dimensional grid of wire positions versus signal and using a computer to interpolate between the grid points to get arbitrary wire positions and, therefore, distributions. The authors present the current results of this effort.
Date: May 1, 1995
Creator: Russell, S.J.; Gilpatrick, J.D.; Power, J.F. & Shurter, R.B.

Characterization of bedded salt for storage caverns -- A case study from the Midland Basin, Texas

Description: The geometry of Permian bedding salt in the Midland Basin is a product of interaction between depositional facies and postdepositional modification by salt dissolution. Mapping high-frequency cycle patterns in cross section and map view using wireline logs documents the salt geometry. Geologically based interpretation of depositional and dissolution processes provides a powerful tool for mapping and geometry of salt to assess the suitability of sites for development of solution-mined storage caverns. In addition, this process-based description of salt geometry complements existing data about the evolution of one of the best-known sedimentary basins in the world, and can serve as a genetic model to assist in interpreting other salts.
Date: June 13, 2000
Creator: Hovorka, Susan D. & Nava, Robin

Characterization of BG28 and KG3 filter glass for Drive Diagnostic Attenuators

Description: BG28 and KG3 filter glasses were tested for use as attenuators in the NIF drive diagnostic (DrD) systems. Tests were performed in the Optical Sciences Laser facility with a 351 nm, 2-step, 3-nsec pulse at fluences ranging up to {approx} 1 J/cm{sup 2}. Single-shot measurements showed no solarization when the samples were allowed to relax for a week after exposure. KG3 filters exhibited no luminescence and no transient pulse distortion. BG28 filters luminesced appreciably and imposed a 'droop' (similar to 'square-pulse distortion') on the signals. The droop parameter is estimated at 0.50 {+-} 0.11 cm{sup 2}/J. Droop is explained in terms of known copper-doped-glass spectroscopy and kinetics (buildup of triplet-state populations, with excited-state absorption). Simulation of the distortion ({approx}1.6%) expected on a 1.8 MJ Haan pulse led to a minor redesign of the Drive Diagnostic with reduced fluence on the BG28 filters to reduce the droop distortion to 0.5%.
Date: November 30, 2007
Creator: Page, R H; Weiland, T & Folta, J

The Characterization of Biotic and Abiotic Media Upgradient and Downgradient of the Los Alamos Canyon Weir

Description: As per the Mitigation Action Plan for the Special Environmental Analysis of the actions taken in response to the Cerro Grande Fire, sediments, vegetation, and small mammals were collected directly up- and downgradient of the Los Alamos Canyon weir, a low-head sediment control structure located on the northeastern boundary of Los Alamos National Laboratory, to determine contaminant impacts, if any. All radionuclides ({sup 3}H, {sup 137}Cs, {sup 238}Pu, {sup 239,240}Pu, {sup 90}Sr, {sup 241}Am, {sup 234}U, {sup 235}U and {sup 238}U) and trace elements (Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, and Tl) in these media were low and most were below regional upper level background concentrations (mean plus three sigma). The very few constituents that were above regional background concentrations were far below screening levels (set from State and Federal standards) for the protection of the human food chain and the terrestrial environment.
Date: January 15, 2006
Creator: Fresquez, P.R.

Characterization of BMS-8-212 for use in penetration simulations

Description: BMS 8-212 lamina properties for use in the computational modeling of aircraft shielding systems were determined in this study. The carbon-reinforced BMS 8-212 composite layups that were tested were unidirectional 0.351-inch thick (45 ply) flat panels. The mechanical responses of the flat panel unidirectional specimens were assumed to be representative of the behavior of the matrix dominated compressive BMS 8-212 lamina responses in the transverse and normal directions. The rate sensitivity of the flat panel specimens was determined for loading rates between 0.001 s{sup -1} and 1000 s{sup -1}. In that regime, the transverse and normal failure stresses were found to increase by approximately 1.5.
Date: October 25, 2007
Creator: Kay, G; Urabe, D; Shields, A & DeTeresa, S

Characterization of brazing alloys with stainless steels

Description: To simulate braze joints, qualitative x-ray mapping of the elemental interactions between brazing alloys and two common types of stainless steels was performed via the electron microprobe. In general both steels, Types 304L and 21- 6-9, react with a particular brazing alloy in a similar manner, the exceptions being the gold--copper brazing alloys which show deeper penetration into the 21-6- 9 stainless steel. (26 figures) (auth)
Date: September 19, 1975
Creator: Riefenberg, D. H.; Doyle, J. H.; Hillyer, R. F. & Bennett, W. S.

Characterization of calculation of in-situ retardation factors of contaminant transport using naturally-radionuclides and rock/water interaction occurring U-Series disequilibria timescales. 1997 annual progress report

Description: 'The research is directed toward a quantitative assessment of contaminant transport rates in fracture-rock systems using uranium-series radionuclides. Naturally occurring uranium-and thorium-series radioactive disequilibria will provide information on the rates of adsorption-desorption and transport of radioactive contaminants as well as on fluid transport and rock dissolution in a natural setting. This study will also provide an improved characterization of preferential flow and contaminant transport at the Idaho Environmental and Engineering Lab. (INEEL) site. To a lesser extent, the study will include rocks in the unsaturated zone. The authors will produce a realistic model of radionuclide migration under unsaturated and saturated field conditions at the INEEL site, taking into account the retardation processes involved in the rock/water interaction. The major tasks are to (1) determine the natural distribution of U, Th, Pa and Ra isotopes in rock minerals. sorbed phases on the rocks, and in fluids from both saturated and unsaturated zones at the site, and (2) study rock/water interaction processes using U/Th series disequilibrium and a statistical analysis-based model for the Geologic heterogeneity plays an important role in transporting contaminants in fractured rocks. Preferential flow paths in the fractured rocks act as a major pathway for transport of radioactive contaminants in groundwaters. The weathering/dissolution of rock by groundwater also influences contaminant mobility. Thus, it is important to understand the hydrogeologic features of the site and their impact on the migration of radioactive contaminants. In this regard, quantification of the rock weathering/dissolution rate and fluid residence time from the observed decay-series disequilibria will be valuable. By mapping the spatial distribution of the residence time of groundwater in fractured rocks, the subsurface preferential flow paths (with high rock permeability and short fluid residence time) can be determined.'
Date: October 30, 1997
Creator: Roback, R.; Murrel, M.; Goldstein, S.; Ku, T.L. & Luo, S.

Characterization of candidate DOE sites for fabricating MOX fuel for lead assemblies

Description: The Office of Fissile Materials Disposition (MD) of the Department of Energy (DOE) is directing the program to disposition US surplus weapons-usable plutonium. For the reactor option for disposition of this surplus plutonium, MD is seeking to contract with a consortium, which would include a mixed-oxide (MOX) fuel fabricator and a commercial US reactor operator, to fabricate and burn MOX fuel in existing commercial nuclear reactors. This option would entail establishing a MOX fuel fabrication facility under the direction of the consortium on an existing DOE site. Because of the lead time required to establish a MOX fuel fabrication facility and the need to qualify the MOX fuel for use in a commercial reactor, MD is considering the early fabrication of lead assemblies (LAs) in existing DOE facilities under the technical direction of the consortium. The LA facility would be expected to produce a minimum of 1 metric ton heavy metal per year and must be operational by June 2003. DOE operations offices were asked to identify candidate sites and facilities to be evaluated for suitability to fabricate MOX fuel LAs. Savannah River Site, Argonne National Laboratory-West, Hanford, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory were identified as final candidates to host the LA project. A Site Evaluation Team (SET) worked with each site to develop viable plans for the LA project. SET then characterized the suitability of each of the five plans for fabricating MOX LAs using 28 attributes and documented the characterization to aid DOE and the consortium in selecting the site for the LA project. SET concluded that each option has relative advantages and disadvantages in comparison with other options; however, each could meet the requirements of the LA project as outlined by MD and SET.
Date: March 1998
Creator: Holdaway, R. F.; Miller, J. W.; Sease, J. D.; Moses, R. J.; O`Connor, D. G.; Carrell, R. D. et al.

Characterization of carbon-based electrochemical capacitor technology from Maxwell Energy Products, Inc.

Description: The electrochemical capacitor devices described in this report were deliverables from the US Department of Energy--Idaho Operations Office (DOE-ID) Contract No. DE-AC07-92ID13404 as part of the US Department of Energy`s (DOE) High Power Energy Storage Program. The Idaho national Engineering and Environmental Laboratory (INEEL) has responsibility for technical management, testing, and evaluation of high-power batteries and electrochemical capacitors under this Program. The DOE has developed various electrochemical capacitors as candidate power assist devices for the Partnership for a New Generation of Vehicles (PNGV) fast response engine requirement. This contract with Maxwell Energy Products, Inc. (Maxwell) was intended to develop a high-energy-density, high-power-density ultracapacitor that is capable of load leveling batteries in electric vehicles. The performance criteria for this device are delivery of 5 W {center_dot} h/kg of useful energy that can be used by the vehicle at an average power rating of 600 W/kg. The capacitor must also have an overall charge/discharge efficiency of 90%, and a useful life of more than 100,000 discharge cycles. The deliverables reported on here are those prepared by Maxwell Energy Products, Inc. at various stages of their developmental program. Deliverables were sent to the INEEL`s Energy Storage Technologies (EST) Laboratory for independent testing and evaluation. This report describes performance testing on three sets of capacitors delivered over a two year period. Additional testing has been done on Set {number_sign}2 described herein, as well as on an additional deliverable from Maxwell. These tests results will be documented in a follow-up report.
Date: April 1, 1998
Creator: Wright, R.B. & Murphy, T.C.

Characterization of Cassini GPHS Fueled-Clad Production Girth Welds

Description: Fueled clads for radioisotope power systems are produced by encapsulating {sup 238}PuO{sub 2} in iridium alloy cups, which are joined at their equators by gas tungsten arc welding. Cracking problems at the girth weld tie-in area during production of the Galileo/Ulysses GPHS capsules led to the development of a first-generation ultrasonic test for girth weld inspection at the Savannah River Plant. A second-generation test and equipment with significantly improved sensitivity and accuracy were jointly developed by the Oak Ridge Y-12 Plant and Westinghouse Savannah River Company for use during the production of Cassini GPHS capsules by the Los Alamos National Laboratory. The test consisted of Lamb wave ultrasonic scanning of the entire girth weld from each end of the capsule combined with a time-of-flight evaluation to aid in characterizing nonrelevant indications. Tangential radiography was also used as a supplementary test for further evaluation of reflector geometry. Each of the 317 fueled GPHS capsules, which were girth welded for the Cassini Program, was subjected to a series of nondestructive tests that included visual, dimensional, helium leak rate, and ultrasonic testing. Thirty-three capsules were rejected prior to ultrasonic testing. Of the 44 capsules rejected by the standard ultrasonic test, 22 were upgraded to flight quality through supplementary testing for an overall process acceptance rate of 82.6%. No confirmed instances of weld cracking were found.
Date: March 23, 2000
Creator: Franco-Ferreira, E.A.

CHARACTERIZATION OF CATALYTIC COMBUSTOR TURBULENCE AND ITS INFLUENCE ON VANE AND ENDWALL HEAT TRANSFER AND ENDWALL FILM COOLING

Description: Endwall heat transfer distributions taken in a large-scale low speed linear cascade facility are documented for mock catalytic and dry low NOx (DLN) combustion systems. Inlet turbulence levels range from about 1.0 percent for the mock Catalytic combustor condition to 14 percent for the mock dry low NOx combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Catalytic combustor endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the mock dry low NOx cases. Turbulence scales have been documented for both cases. Inlet boundary layers are relatively thin for the mock catalytic combustor case while inlet flow approximates a channel flow with high turbulence for the mock DLN combustor case. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the mock catalytic and DLN combustor inlet cases. Both midspan and 95 percent span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.
Date: October 1, 2002
Creator: Ames, Forrest E.

Characterization of Cathode Materials for Rechargeable Lithium Batteries using Synchrotron Based In Situ X-ray Techniques

Description: The emergence of portable telecommunication, computer equipment and ultimately hybrid electric vehicles has created a substantial interest in manufacturing rechargeable batteries that are less expensive, non-toxic, operate for longer time, small in size and weigh less. Li-ion batteries are taking an increasing share of the rechargeable battery market. The present commercial battery is based on a layered LiCoO{sub 2} cathode and a graphitized carbon anode. LiCoO{sub 2} is expensive but it has the advantage being easily manufactured in a reproducible manner. Other low cost layered compounds such as LiNiO{sub 2}, LiNi{sub 0.85}Co{sub 0.15}O{sub 2} or cubic spinels such as LiMn{sub 2}O{sub 4} have been considered. However, these suffer from cycle life and thermal stability problems. Recently, some battery companies have demonstrated a new concept of mixing two different types of insertion compounds to make a composite cathode, aimed at reducing cost and improving self-discharge. Reports clearly showed that this blending technique can prevent the decline in ·capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and phase transitions for these composite cathodes. Understanding the structure and structural changes of electrode materials during the electrochemical cycling is the key to develop better .lithium ion batteries. The successful commercialization of the· lithium-ion battery is mainly built on the advances in solid state chemistry of the intercalation compounds. Most of the progress in understanding the lithium ion battery materials has been obtained from x-ray diffraction studies. Up to now, most XRD studies on lithium-ion battery materials have been done ex situ. Although these ex situ XRD studies have provided important information· about the structures of battery materials, they do face three major problems. First of all, the pre-selected charge (discharge) states may not be representative for the full picture of the structural ...
Date: May 23, 2007
Creator: Yang, Xiao-Qing

Characterization of CdZnTe ambient temperature detectors

Description: A great deal of interest has been generated in the use of cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) detectors for ambient temperature detection of radionuclides. The addition of zinc to CdTe provides several benefits that enhance the materials operational characteristics at ambient temperature. Recent movement in the industry is to produce larger volume detectors using CdZnTe without much known about the effects of larger geometry on performance. The purpose of this study is to get an idea of the relationship of detector performance to both area and thickness variations.
Date: September 1, 1994
Creator: Lavietes, A.

Characterization of celotex and thermodynamic calculations of the formation of corrosion precursors on beryllium

Description: The importance of safe and long-term storage of nuclear weapons components has drawn attention towards the characterization and understanding of the corrosion precursors formed on beryllium. A complete compositional and thermal characterization of celotex was carried out using energy dispersive spectroscopy, inductively coupled plasma-mass spectroscopic analysis, ion chromatography, and thermogravimetric analysis. Both fluoride and sulfate anions in addition to chloride as well as several metal ions are found to be present. The chloride present in celotex is lost at moderate temperatures 200 < T < 400 C, which may have important consequences on the formation of corrosion precursors. Equilibrium thermodynamic calculations on the stability of beryllium oxide in chlorinated environments were performed for a model system composed by beryllium, carbon, chlorine, hydrogen and oxygen. The calculations were aimed at describing the equilibrium, long-term behavior of a beryllium surface and its interaction with chlorine in a closed environment. The authors found that (i) carbon is essential for the formation of BeCl{sub 2}, and (ii) the chlorine-to-hydrogen ratio in chlorinated solvents is an important quantity since for solvents with chlorine-to-hydrogen ratio higher than 1, BeCl{sub 2} is not formed independently of the amount of solvent.
Date: April 1, 1999
Creator: Diaz-Ortiz, A.; Stolk, J.; Kim, J.; Sanchez, J.M. & Manthiram, A.

Characterization of Changes in Colloid and DNAPL Affecting Surface Chemistry and Remediation

Description: Field work was completed in March 2004 to collect soil borings from 4 background locations. Samples are presently being analyzed for VOC concentrations, grain size mineralology and microbial populations. Results are not yet available from these activities. Analysis is on-going to characterize a DNAPL sample collected from the M-area settling basin. Previous results suggested that the interfacial tension of this sample was very low and the acidity high. Recent observations and analysis have lead to a revised hypothesis regarding the role of inorganic constituents that partition into the DNAPL as it was disposed with many other waste products. A white precipitate can form when the volume of DNAPL is high relative to the volume of water. This precipitate accumulates at the DNAPL-water interface causing the low interfacial tension. As far as I know, this is the first research available that identifies the important role of inorganic constituents in a DNAPLon interfaial behavior of DNAPLs i n the subsurface.
Date: June 1, 2003
Creator: Powers, Susan E.

A characterization of check valve degradation and failure experience in the nuclear power industry: 1984-1990. Volume 1

Description: Check valve operating problems in recent years have resulted in significant operating transients, increased cost and decreased system availability. As a result, additional attention has beau given to check valves by utilities (resulting in the formation of the Nuclear Industry Check Valve Group), as well as the US Nuclear Regulatory Commission and the American Society of Mechanical Engineers Operation and Maintenance Committee. All these organizations have the fundamental goal of ensuring reliable operation of check valves. A key ingredient to an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. A detailed review of historical failure data, available through the Institute of Nuclear Power Operation`s Nuclear Plant Reliability Data System, has been conducted. The focus of the review is on check valve failures that have involved significant degradation of the valve internal parts. A variety of parameters are considered, including size, age, system of service, method of failure discovery, the affected valve parts, attributed causes, and corrective actions.
Date: September 1, 1993
Creator: Casada, D.A. & Todd, M.D.

A characterization of check valve degradation and failure experience in the nuclear power industry: 1991 Failures, Volume 2

Description: Review and characterization of check valve failures taken from the Institute of Nuclear Power Operation`s Nuclear Plant Reliability Data System was performed in accordance with part two of a three-phase project sponsored by the US Nuclear Regulatory Commission. The analysis was performed for check valve failures occurring in 1991 and is intended to update the previous analysis performed for the time period 1984--1990. To maintain consistency and for ease of the 1991 analysis presents the same parameters and cross-correlations in essentially the same format as the 1984--1990 study. Additional data was obtained for the 1991 analysis, including information related to specific check valve type. This information is presented in a separate section of the report.
Date: July 1, 1995
Creator: McElhaney, K.L.

Characterization of Chemically Modified Enzymes for Bioremediation Reactions

Description: Remediation processes frequently involve species possessing limited solubility in water. For this project, we were interested in novel strategies using molecularly modified enzymes with enhanced activity and stability for remediation of recalcitrant compounds in organic solvents. Performance of naturally occurring enzymes is usually quite limited in such organic environments. The primary objective of the work was to gain a fundamental understanding of the molecular and catalytic properties of enzymes that have been chemically modified so that they are catalytically active and chemically stable in organic solvents. The premise was that stabilized and activated enzymes, which can function under harsh chemical conditions, are optimally suited for bioremediation in nonaqueous media where substrates of interest are more soluble and processed with greater efficiency. This unique strategy was examined with respect to the degradation of chlorophenols and PCBs.
Date: December 31, 2000
Creator: Davison, Brian H.

Characterization of chemically modified enzymes for bioremediation-reactions. 1997 annual progress report

Description: 'Many, if not most, biological transformation reactions of interest to US Department of Energy (DOE) site remediation involve substrates that are only sparingly soluble in aqueous environments. Hence, destruction of these recalcitrant and toxic materials would benefit tremendously if their degradation could be performed in nonaqueous environments. Organic biocatalysis may be motivated by the nature of the substrate itself, augmented mass transport, ease of product recovery, or novel reaction pathways afforded by the organic solvent. For instance, polychlorinated biphenyls (PCBs) are sparingly soluble in water, but may be more effectively processed when solubilized by organic liquids. However, naturally-occurring enzymes are not soluble in organic solvents. Indeed, most spontaneously denature and, depending on the solvent used, typically form inactive and insoluble precipitates. The objective of the current work is to gain a fundamental understanding of the molecular and catalytic properties of enzymes that have been chemically-modified so that they are catalytically-active and chemically-thermally-stable in organic solvents. The premise for this study is that highly stable enzymes which are catalytically active in both water and in a range of organic solvents are optimally suited for bioremediation where substrates of interest are more soluble and may be processed with greater specificity in nonaqueous solvents. The proposed research program will enable the development of nonaqueous bioremediation technologies for the treatment of DOE sites contaminated with aqueous-insoluble organic compounds. Such compounds may include dense nonaqueous phase liquids, trichloroethylene (TCE), trichloroacetic acid, trans-dichloroethylene, diesel fuel, and PCBs. These compounds have been identified as targets for technology development in the ``EM Technology Needs Database,'''' and are contaminants at the following DOE sites: K-25 Site plumes; ORNL WAGS 1, 4, and 5; Paducah plumes; Portsmouth plumes; the X-701B Holding Pond; and the Y-12 Poplar Creek and Bear Creek Watersheds.'
Date: September 1, 1997
Creator: Kaufman, E.N. & Adams, M.W.W.

Characterization of Chemically Modified Hyperthermophilic Enzymes for Chemical Syntheses and Bioremediation Reactions

Description: Remediation processes frequently involve species possessing limited solubility in water. We are interested in novel strategies that use molecularly modified enzymes with enhanced activity and stability for the remediation of recalcitrant compounds in organic solvents. The performance of naturally-occurring enzymes is usually quite limited in such organic environments. The primary objective of the current work is to gain a fundamental understanding of the molecular and catalytic properties of enzymes that have been chemically modified so that they are catalytically active and chemically-stable in organic solvents. The premise for this study is that stabilized and activated enzymes, which can function at hash chemical conditions, are optimally suited for bioremediation in nonaqueous media where substrates of interest are more soluble and processed with greater efficiency. This unique strategy is examined with respect to the degradation of chlorophenols and PCBs.
Date: June 1, 1999
Creator: Davison, Brian H. & Adams, Michael

Characterization of chemically modified hyperthermophilic enzymes for chemical syntheses and bioremediation reactions. 1998 annual progress report

Description: 'Remediation processes frequently involve species possessing limited solubility in water. The authors are interested in novel strategies that use molecularly-engineered enzymes with enhanced activity and stability for the remediation of recalcitrant compounds in organic media. Organic biocatalysis may be motivated by the nature of the substrate itself, or by augmented mass transport, ease of product recovery, or novel reaction pathways afforded by the organic solvent. However, naturally-occurring enzymes are usually subject to quite limited activity and stability in such organic environments. The objective of the current work is to gain a fundamental understanding of the molecular and catalytic properties of enzymes that have been chemically-modified so that they are catalytically-active and chemically-thermally-stable in organic solvents. The premise for this study is that highly stable enzymes which are catalytically active in both water and in a range of organic solvents are optimally suited for bioremediation where substrates of interest are more soluble and may be processed with greater specificity in nonaqueous solvents. This bioprocessing system will be assessed using PCB''s, DNAPL''s and PAH''s. As of the second of year of a 3-year project, the authors have obtained promising results for both the demonstration of the proposed remediation strategy and fundamental understanding of the enzymatic catalysis in organic media. In one of the efforts, ligninase (LiP) was modified by poly(ethylene glycol) (PEG) and examined for the degradation of pentachlorophenol (PCP) in water-solvent mixtures. In the other efforts, basic catalytic behaviors of the chemically modified hyperthermophilic metalloenzymes including ferredoxin, hydrogenase and aldehyde oxidoreductase were examined in organic solvents.'
Date: June 1, 1998
Creator: Kaufman, E.N. & Adams, M.W.W.