Aquifer Testing Recommendations for Well 299-W15-225: Supporting Phase I of the 200-ZP-1 Groundwater Operable Unit Remedial Design (open access)

Aquifer Testing Recommendations for Well 299-W15-225: Supporting Phase I of the 200-ZP-1 Groundwater Operable Unit Remedial Design

Aquifer characterization needs are currently being assessed to optimize pump-and-treat remedial strategies within the 200-ZP-1 Operable Unit (OU), specifically for the immediate area of the 241-TX-TY Tank Farm. Currently, 14 extraction wells are actively used in the Interim Record of Decision ZP-1 pump-and-treat system to remediate the existing groundwater contamination within this general area. Four of these wells (299-W15-40, 299-W15-43, 299-W15-44, and 299-W15-765) are targeted to remediate contamination within the immediate 241-TX-TY Tank Farm area. The major contaminant of concern (COC) for the 200-ZP-1 OU is carbon tetrachloride. Other COC’s include total chromium (trivalent [III] and hexavalent [VI], nitrate, trichloroethlyene, iodine-129, technetium-99, and tritium.
Date: March 10, 2009
Creator: Spane, Frank A. & Newcomer, Darrell R.
Object Type: Report
System: The UNT Digital Library
CODE ACCEPTANCE OF A NEW JOINING TECHNOLOGY FOR STORAGE CONTAINMENTS [REISSUE] (open access)

CODE ACCEPTANCE OF A NEW JOINING TECHNOLOGY FOR STORAGE CONTAINMENTS [REISSUE]

One of the activities associated with cleanup throughout the Department of Energy (DOE) complex is packaging radioactive materials into storage containers. Much of this work will be performed in high-radiation environments requiring fully remote operations, for which existing, proven systems do not currently exist. These conditions require a process that is capable of producing acceptable (defect-free) welds on a consistent basis; the need to perform weld repair, under fully-remote operations, can be extremely costly and time consuming. Current closure-welding technologies (fusion welding) are not well suited for this application and will present risk to cleanup cost and schedule. To address this risk, Fluor and the Pacific Northwest National Laboratory (PNNL) are proposing that a new and emerging joining technology, Friction Stir Welding (FSW), be considered for this work. FSW technology has been demonstrated in other industries (aerospace and marine) to produce near flaw-free welds on a consistent basis. FSW is judged capable of providing the needed performance for fully-remote closure welding of containers for radioactive materials for the following reasons: FSW is a solid-state process; material is not melted. FSW does not produce the type of defects associated with fusion welding, e.g., solidification-induced porosity, cracking, and distortion due to weld …
Date: March 10, 2009
Creator: GR, CANNELL; GJ, GRANT & BE, HILL
Object Type: Article
System: The UNT Digital Library
Development and Characterization of Boehmite Component Simulant (open access)

Development and Characterization of Boehmite Component Simulant

According to Bechtel National Inc.’s (BNI’s) Test Specification 24590-PTF-TSP-RT-06-006, Rev 0, “Simulant Development to Support the Development and Demonstration of Leaching and Ultrafiltration Pretreatment Processes,” simulants for boehmite, gibbsite, and filtration are to be developed that can be used in subsequent bench and integrated testing of the leaching/filtration processes. These simulants will then be used to demonstrate the leaching process and to help refine processing conditions that may impact safety basis considerations (Smith 2006). This report documents the results of the boehmite simulant development.
Date: March 10, 2009
Creator: Russell, Renee L.; Peterson, Reid A.; Smith, Harry D.; Rinehart, Donald E.; Aker, Pamela M. & Buck, Edgar C.
Object Type: Report
System: The UNT Digital Library
Development of Bulk Nanocrystalline Cemented Tungsten Carbide for Industrial Applicaitons (open access)

Development of Bulk Nanocrystalline Cemented Tungsten Carbide for Industrial Applicaitons

This report contains detailed information of the research program entitled "Development of Bulk Nanocrystalline Cemented Tungsten Carbide Materials for Industrial Applications". The report include the processes that were developed for producing nanosized WC/Co composite powders, and an ultrahigh pressure rapid hot consolidation process for sintering of nanosized powders. The mechanical properties of consolidated materials using the nanosized powders are also reported.
Date: March 10, 2009
Creator: Z. Zak Fang, H. Y. Sohn
Object Type: Report
System: The UNT Digital Library
Effect of Heat and Electricity Storage and Reliability on Microgrid Viability: A Study of Commercial Buildings in California and New York States (open access)

Effect of Heat and Electricity Storage and Reliability on Microgrid Viability: A Study of Commercial Buildings in California and New York States

Berkeley Lab has for several years been developing methods for selection of optimal microgrid systems, especially for commercial building applications, and applying these methods in the Distributed Energy Resources Customer Adoption Model (DER-CAM). This project began with 3 major goals: (1) to conduct detailed analysis to find the optimal equipment combination for microgrids at a few promising commercial building hosts in the two favorable markets of California and New York, (2) to extend the analysis capability of DER-CAM to include both heat and electricity storage, and (3) to make an initial effort towards adding consideration of power quality and reliability (PQR) to the capabilities of DER-CAM. All of these objectives have been pursued via analysis of the attractiveness of a Consortium for Electric Reliability Technology Solutions (CERTS) Microgrid consisting of multiple nameplate 100 kW Tecogen Premium Power Modules (CM-100). This unit consists of an asynchronous inverter-based variable speed internal combustion engine genset with combined heat and power (CHP) and power surge capability. The essence of CERTS Microgrid technology is that smarts added to the on-board power electronics of any microgrid device enables stable and safe islanded operation without the need for complex fast supervisory controls. This approach allows plug and …
Date: March 10, 2009
Creator: Stadler, Michael; Marnay, Chris; Siddiqui, Afzal; Lai, Judy; Coffey, Brian & Aki, Hirohisa
Object Type: Report
System: The UNT Digital Library
Feasibility of Recycling Plutonium and Minor Actinides in Light Water Reactors Using Hydride Fuel (open access)

Feasibility of Recycling Plutonium and Minor Actinides in Light Water Reactors Using Hydride Fuel

The objective of this DOE NERI program sponsored project was to assess the feasibility of improving the plutonium (Pu) and minor actinide (MA) recycling capabilities of pressurized water reactors (PWRs) by using hydride instead of oxide fuels. There are four general parts to this assessment: 1) Identifying promising hydride fuel assembly designs for recycling Pu and MAs in PWRs 2) Performing a comprehensive systems analysis that compares the fuel cycle characteristics of Pu and MA recycling in PWRs using the promising hydride fuel assembly designs identified in Part 1 versus using oxide fuel assembly designs 3) Conducting a safety analysis to assess the likelihood of licensing hydride fuel assembly designs 4) Assessing the compatibility of hydride fuel with cladding materials and water under typical PWR operating conditions Hydride fuel was found to offer promising transmutation characteristics and is recommended for further examination as a possible preferred option for recycling plutonium in PWRs.
Date: March 10, 2009
Creator: Greenspan, Ehud; Todreas, Neil & Taiwo, Temitope
Object Type: Report
System: The UNT Digital Library
Final Technical Report: Genetic and Molecular Analysis of a new control pathway in assimilate partitioning. (open access)

Final Technical Report: Genetic and Molecular Analysis of a new control pathway in assimilate partitioning.

Assimilate partitioning refers to the systemic distribution of photoassimilate from sites of primary assimilation (source tissue) to import-dependent tissues and organs (sinks). One of the defining questions in this area is how plants balance source productivity with sink demand. We discovered a sucrose-sensing signal transduction pathway that controls the activity of BvSUT1, a proton-sucrose symporter in sugar beet leaf tissue. Sucrose symporters are responsible for sucrose accumulation in the phloem of many plants and, therefore, they mediate the pivotal step in the long-distance transport of photoassimilate to non-photosynthetic tissues, such as roots and seed. We previously showed that sucrose transport activity is directly proportional to the transcription rate of BvSUT1 and that symporter mRNA and protein have high rates of turnover with half-lives on the order of 2 h. We further demonstrated that symporter transcription is regulated by sucrose levels in the leaf and that sucrose-dependent regulation of BvSUT1 transcription is mediated, at least in part, by a protein phosphorylation relay pathway. The goal of the experiments during this current grant were to use genetic and molecular approaches to identify essential components of this vital regulatory system. The initial objectives were to: (1) to characterize Arabidopsis mutants we've isolated that …
Date: March 10, 2009
Creator: Bush, Daniel, R.
Object Type: Report
System: The UNT Digital Library
Growth and characterization of superconducting spinel oxide LiTi2O4 thin films (open access)

Growth and characterization of superconducting spinel oxide LiTi2O4 thin films

Epitaxial films of LiTi{sub 2}O{sub 4} on single crystalline substrates of MgAl{sub 2}O{sub 4}, MgO, and SrTiO{sub 3} provide model systems to systematically explore the effects of lattice strain and microstructural disorder on the superconducting state. Lattice strain that affects bandwidth gives rise to variations in the superconducting and normal state properties. Microstructural disorder, such as antiphase boundaries that give rise to Ti network disorder, reduces the critical temperature, and Ti network disorder combined with Mg interdiffusion lead to a much more dramatic effect on the superconducting state. Surface sensitive X-ray absorption spectroscopy has identified Ti to retain site symmetry and average valence of the bulk material regardless of film thickness.
Date: March 10, 2009
Creator: Chopdekar, R.V.; Wong, F.; Takamura, Y.; Arenholz, E. & Suzuki, Y.
Object Type: Article
System: The UNT Digital Library
Manufacture of Alumina-Forming Austenitic Steel Alloys by Conventional Casting and Hot-Working Methods (open access)

Manufacture of Alumina-Forming Austenitic Steel Alloys by Conventional Casting and Hot-Working Methods

Oak Ridge National Laboratory (ORNL) and Carpenter Technology Corporation (CarTech) participated in an in-kind cost share cooperative research and development agreement (CRADA) effort under the auspices of the Energy Efficiency and Renewable Energy (EERE) Technology Maturation Program to explore the feasibility for scale up of developmental ORNL alumina-forming austenitic (AFA) stainless steels by conventional casting and rolling techniques. CarTech successfully vacuum melted 301b heats of four AFA alloy compositions in the range of Fe-(20-25)Ni-(12-14)Cr-(3-4)Al-(l-2.5)Nb wt.% base. Conventional hot/cold rolling was used to produce 0.5-inch thick plate and 0.1-inch thick sheet product. ORNL subsequently successfully rolled the 0.1-inch sheet to 4 mil thick foil. Long-term oxidation studies of the plate form material were initiated at 650, 700, and 800 C in air with 10 volume percent water vapor. Preliminary results indicated that the alloys exhibit comparable (good) oxidation resistance to ORNL laboratory scale AFA alloy arc casting previously evaluated. The sheet and foil material will be used in ongoing evaluation efforts for oxidation and creep resistance under related CRADAs with two gas turbine engine manufacturers. This work will be directed to evaluation of AFA alloys for use in gas turbine recuperators to permit higher-temperature operating conditions for improved efficiencies and reduced …
Date: March 10, 2009
Creator: Brady, M. P.; Yamamoto, Y. & Magee, J. H.
Object Type: Report
System: The UNT Digital Library
Measurement of fragmentation and functionalization pathways in the multistep heterogeneous oxidation of organic aerosol (open access)

Measurement of fragmentation and functionalization pathways in the multistep heterogeneous oxidation of organic aerosol

The competition between the addition of polar, oxygen-containing functional groups (functionalization) and the cleavage of C-C bonds (fragmentation) has a governing influence on the change in volatility of organic species upon atmospheric oxidation, and hence on the loading of tropospheric organic aerosol. However the branching between these two channels is generally poorly constrained for oxidized organics. Here we determine functionalization/fragmentation branching ratios for organics spanning a range of oxidation levels, using the heterogeneous oxidation of squalane (C30H62) as a model system. Squalane particles are exposed to high concentrations of OH in a flow reactor, and measurements of particle mass and elemental ratios enable the determination of absolute elemental composition (number of oxygen, carbon, and hydrogen atoms) of the oxidized particles. At low OH exposures, the oxygen content of the organics increases, indicating that functionalization dominates, whereas at higher exposures the amount of carbon in the particles decreases, indicating the increasing importance of fragmentation processes. Once the organics are moderately oxidized (O/C~;;0.4), fragmentation completely dominates, and the increase in O/C ratio upon further oxidation is due to the loss of carbon rather than the addition of oxygen. These results suggest that fragmentation reactions may be key steps in the atmospheric formation …
Date: March 10, 2009
Creator: Kroll, Jesse H.; Smith, Jared D.; Che, Dung L.; Kessler, Sean H.; Worsnop, Douglas R. & Wilson, Kevin R.
Object Type: Article
System: The UNT Digital Library
October 2008 Monitoring Results for Morrill, Kansas. (open access)

October 2008 Monitoring Results for Morrill, Kansas.

In September 2005, the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) initiated periodic sampling of groundwater in the vicinity of a grain storage facility formerly operated by the CCC/USDA at Morrill, Kansas. The sampling at Morrill is being performed on behalf of the CCC/USDA by Argonne National Laboratory, in accord with a monitoring program approved by the Kansas Department of Health and Environment (KDHE 2005), to monitor levels of carbon tetrachloride contamination identified in the groundwater at this site (Argonne 2004, 2005a). This report provides results for the most recent monitoring event, in October 2008. Under the KDHE-approved monitoring plan (Argonne 2005b), groundwater was initially sampled twice yearly for a period of two years (in fall 2005, in spring and fall 2006, and in spring and fall 2007). The samples were analyzed for volatile organic compounds (VOCs), as well as for selected geochemical parameters to aid in the evaluation of possible natural contaminant degradation (reductive dechlorination) processes in the subsurface environment. During the two-year period, the originally approved scope of the monitoring was expanded to include vegetation sampling (initiated in October 2006) and surface water and stream bed sediment sampling (initiated in March 2007, after a visual …
Date: March 10, 2009
Creator: LaFreniere, L. M.
Object Type: Report
System: The UNT Digital Library
Recent Results from the MINOS Experiment (open access)

Recent Results from the MINOS Experiment

MINOS is an accelerator neutrino oscillation experiment at Fermilab. An intense high energy neutrino beam is produced at Fermilab and sent to a near detector on the Fermilab site and also to a 5 kTon far detector 735 km away in the Soudan mine in northern Minnesota. The experiment has now had several years of running with millions of events in the near detector and hundreds of events recorded in the far detector. I will report on the recent results from this experiment which include precise measurement of |{Delta}m{sup 2}{sub 32}|, analysis of neutral current data to limit the component of sterile neutrinos and the search for {nu}{sub {mu}} {yields} {nu}{sub e} conversion. The focus will be on the analysis of data for {nu}{sub {mu}} {yields} {nu}{sub e} conversion. Using data from an exposure of 3.14 x 10{sup 20} protons on target, we have selected electron type events in both the near and the far detector. The near detector is used to measure the background which is extrapolated to the far detector. We have found 35 events in the signal region with a background expectation of 27 {+-} 5(stat) {+-} 2(syst). Using this observation we set a 90% C.L. limit …
Date: March 10, 2009
Creator: Diwan,M.V.
Object Type: Article
System: The UNT Digital Library
A Superbend X-Ray Microdiffraction Beamline at the Advanced Light Source (open access)

A Superbend X-Ray Microdiffraction Beamline at the Advanced Light Source

Beamline 12.3.2 at the Advanced Light Source is a newly commissioned beamline dedicated to x-ray microdiffraction. It operates in both monochromatic and polychromatic radiation mode. The facility uses a superconducting bending magnet source to deliver an X-ray spectrum ranging from 5 to 22 keV. The beam is focused down to {approx} 1 um size at the sample position using a pair of elliptically bent Kirkpatrick-Baez mirrors enclosed in a vacuum box. The sample placed on high precision stages can be raster-scanned under the microbeam while a diffraction pattern is taken at each step. The arrays of diffraction patterns are then analyzed to derive distribution maps of phases, strain/stress and/or plastic deformation inside the sample.
Date: March 10, 2009
Creator: Tamura, N.; Kunz, M.; Chen, K.; Celestre, R. S.; MacDowell, A. A. & Warwick, T.
Object Type: Article
System: The UNT Digital Library
Thermal neutron imaging in an active interrogation environment (open access)

Thermal neutron imaging in an active interrogation environment

We have developed a thermal-neutron coded-aperture imager that reveals the locations of hydrogenous materials from which thermal neutrons are being emitted. This imaging detector can be combined with an accelerator to form an active interrogation system in which fast neutrons are produced in a heavy metal target by means of xcitation by high energy photons. The photo-induced neutrons can be either prompt or delayed, depending on whether neutronemitting fission products are generated. Provided that there are hydrogenous materials close to the target, some of the photo-induced neutrons slow down and emerge from the surface at thermal energies. These neutrons can be used to create images that show the location and shape of the thermalizing materials. Analysis of the temporal response of the neutron flux provides information about delayed neutrons from induced fission if there are fissionable materials in the target. The combination of imaging and time-of-flight discrimination helps to improve the signal-to-background ratio. It is also possible to interrogate the target with neutrons, for example using a D-T generator. In this case, an image can be obtained from hydrogenous material in a target without the presence of heavy metal. In addition, if fissionable material is present in the target, probing …
Date: March 10, 2009
Creator: Vanier, Peter E. & Forman, Leon
Object Type: Report
System: The UNT Digital Library
VOC Destruction by Catalytic Combustion Microturbine (open access)

VOC Destruction by Catalytic Combustion Microturbine

This project concerned the application of a catalytic combustion system that has been married to a micro-turbine device. The catalytic combustion system decomposes the VOC's and transmits these gases to the gas turbine. The turbine has been altered to operate on very low-level BTU fuels equivalent to 1.5% methane in air. The performance of the micro-turbine for VOC elimination has some flexibility with respect to operating conditions, and the system is adaptable to multiple industrial applications. The VOC source that was been chosen for examination was the emissions from coal upgrading operations. The overall goal of the project was to examine the effectiveness of a catalytic combustion based system for elimination of VOCs while simultaneously producing electrical power for local consumption. Project specific objectives included assessment of the feasibility for using a Flex-Microturbine that generates power from natural gas while it consumes VOCs generated from site operations; development of an engineering plan for installation of the Flex-Microturbine system; operation of the micro-turbine through various changes in site and operation conditions; measurement of the VOC destruction quantitatively; and determination of the required improvements for further studies. The micro-turbine with the catalytic bed worked effectively to produce power on levels of fuel …
Date: March 10, 2009
Creator: Barton, Tom
Object Type: Report
System: The UNT Digital Library
Year of Birth Determination Using Radiocarbon Dating of Dental Enamel (open access)

Year of Birth Determination Using Radiocarbon Dating of Dental Enamel

Radiocarbon dating is typically an archaeological tool rather than a forensic one. Recently however, we have shown that the amount of radiocarbon present in tooth enamel, as a result of nuclear bomb testing during the cold war, is a remarkably accurate indicator of when a person is born. Enamel isolated from human teeth is processed to form graphite and carbon-14 ({sup 14}C) levels are measured using accelerator mass spectrometry. Since there is no turnover of enamel after it is formed, {sup 14}C levels in the enamel represent {sup 14}C levels in the atmosphere at the time of its formation. In this paper we describe the strategy used to determine the date of birth of an individual based on radiocarbon levels in tooth enamel, focusing on the methodology of this strategy. Year of birth information can significantly assist police investigators when the identity of a deceased individual is unknown. In such cases police will try to match particulars of the unidentified individual (which is often only gender and/or an estimate of age), with particulars from missing persons lists.
Date: March 10, 2009
Creator: Buchholz, B. A. & Spalding, K. L.
Object Type: Article
System: The UNT Digital Library
Constitutive modeling of Radiation effects on the Permanent Set in a silicone elastomer (open access)

Constitutive modeling of Radiation effects on the Permanent Set in a silicone elastomer

When a networked polymeric composite under high stress is subjected to irradiation, the resulting chemical changes like chain scissioning and cross-link formation can lead to permanent set and altered elastic modulus. Using a commercial silicone elastomer as a specific example we show that a simple 2-stage Tobolsky model in conjunction with Fricker's stress-transfer function can quantitatively reproduce all experimental data as a function of radiation dosage and the static strain at which radiation is turned on, including permanent set, stress-strain response, and net cross-linking density.
Date: March 10, 2008
Creator: Maiti, A.; Gee, R.; Weisgraber, T.; Chinn, S. & Maxwell, R.
Object Type: Article
System: The UNT Digital Library
Electrode Materials with the Na0.44MnO2 Structure: Effect ofTitanium Substitution on Physical and Electrochemical Properties (open access)

Electrode Materials with the Na0.44MnO2 Structure: Effect ofTitanium Substitution on Physical and Electrochemical Properties

The physical and electrochemical properties of LixMnO2 and LixTi0.11Mn0.89O2 synthesized from precursors made by glycine-nitrate combustion (GNC) and solid-state synthesis methods (SS) are examined in this paper. The highest specific capacities in lithium cells are obtained for SS-LixMnO2 electrodes at low current densities, but GNC-LixTi0.11Mn0.89O2 electrodes show the best high rate performance. These results can be explained by changes in the voltage characteristics and differences in the particle morphologies induced by the Ti-substitution and synthesis method. Ti-substitution also results in a decrease in the electronic conductivity, but greatly improves the thermal properties and imparts dissolution resistance to the electrode. For these reasons, it is preferable to use LixTi0.11MnO0.89O2 in lithium battery configurations rather than LixMnO2. Suggestions for improving the electrochemical performance of the Ti-substituted variant are given based on the results described herein.
Date: March 10, 2008
Creator: Doeff, Marca M; Saint, Juliette A.; Doeff, Marca M & Wilcox, James D.
Object Type: Article
System: The UNT Digital Library
ELECTRONICS UPGRADE OF HIGH RESOLUTION MASS SPECTROMETERS (open access)

ELECTRONICS UPGRADE OF HIGH RESOLUTION MASS SPECTROMETERS

High resolution mass spectrometers are specialized systems that allow researchers to determine the exact mass of samples to four significant digits by using magnetic and electronic sector mass analyzers. Many of the systems in use today at research laboratories and universities were designed and built more than two decades ago. The manufacturers of these systems have abandoned the support for some of the mass spectrometers and parts to power and control them have become scarce or obsolete. The Savannah River National Laboratory has been involved in the upgrade of the electronics and software for these legacy machines. The Electronics Upgrade of High Resolution Mass Spectrometers consists of assembling high-end commercial instrumentation from reputable manufacturers with a minimal amount of customization to replace the electronics for the older systems. By taking advantage of advances in instrumentation, precise magnet control can be achieved using high resolution current sources and continuous feedback from a high resolution hall-effect probe. The custom equipment include a precision voltage divider/summing amplifier chassis, high voltage power supply chassis and a chassis for controlling the voltage emission for the mass spectrometer source tube. The upgrade package is versatile enough to interface with valve control, vacuum and other instrumentation. Instrument …
Date: March 10, 2008
Creator: Mcintosh, J & Joe Cordaro, J
Object Type: Article
System: The UNT Digital Library
Evaluating cloud retrieval algorithms with the ARM BBHRP framework (open access)

Evaluating cloud retrieval algorithms with the ARM BBHRP framework

Climate and weather prediction models require accurate calculations of vertical profiles of radiative heating. Although heating rate calculations cannot be directly validated due to the lack of corresponding observations, surface and top-of-atmosphere measurements can indirectly establish the quality of computed heating rates through validation of the calculated irradiances at the atmospheric boundaries. The ARM Broadband Heating Rate Profile (BBHRP) project, a collaboration of all the working groups in the program, was designed with these heating rate validations as a key objective. Given the large dependence of radiative heating rates on cloud properties, a critical component of BBHRP radiative closure analyses has been the evaluation of cloud microphysical retrieval algorithms. This evaluation is an important step in establishing the necessary confidence in the continuous profiles of computed radiative heating rates produced by BBHRP at the ARM Climate Research Facility (ACRF) sites that are needed for modeling studies. This poster details the continued effort to evaluate cloud property retrieval algorithms within the BBHRP framework, a key focus of the project this year. A requirement for the computation of accurate heating rate profiles is a robust cloud microphysical product that captures the occurrence, height, and phase of clouds above each ACRF site. Various …
Date: March 10, 2008
Creator: Mlawer,E.; Dunn,M.; Mlawer, E.; Shippert, T.; Troyan, D.; Johnson, K. L. et al.
Object Type: Article
System: The UNT Digital Library
Final Report for LDRD Project 06-ERD-063 (open access)

Final Report for LDRD Project 06-ERD-063

None
Date: March 10, 2008
Creator: Beller, H R; Chakicherla, A; Coleman, M A; Esser, B K; Kane, S R; Legler, T C et al.
Object Type: Report
System: The UNT Digital Library
The First Aerosol Indirect Effect: Beyond Twomey (open access)

The First Aerosol Indirect Effect: Beyond Twomey

The traditional first aerosol indirect effect or the Twomey effect involves several fundamental assumptions. Some of the assumptions (e.g., constant liquid water content) are explicitly stated in studies of the Twomey effect whereas others are only implicitly embedded in the quantitative formulation. This work focuses on examining the implicit assumptions. In particular, we will show that anthropogenic pollution not only increases aerosol loading and droplet concentrations but also alters the relative dispersions of both the aerosol and subsequent droplet size distributions. The indirect effects resulting from the two altered relative dispersions (aerosol dispersion effect and droplet dispersion effect) are likely opposite in sign and proportional in magnitude to the conventional Twomey effect. This result suggests that the outstanding problems of the Twomey effect (i.e., large uncertainty and overestimation reported in literature) may lie with violation of the constant spectral shapes of aerosol and droplet size distributions implicitly assumed in evaluation of the Twomey effect, and therefore, further progress in understanding and quantification of the first aerosol indirect effect demands moving beyond the traditional paradigm originally conceived by Twomey.
Date: March 10, 2008
Creator: Liu, Y.; Dunn, M. & Daum, P.
Object Type: Article
System: The UNT Digital Library
A human breast cell model of pre-invasive to invasive transition (open access)

A human breast cell model of pre-invasive to invasive transition

A crucial step in human breast cancer progression is the acquisition of invasiveness. There is a distinct lack of human cell culture models to study the transition from pre-invasive to invasive phenotype as it may occur 'spontaneously' in vivo. To delineate molecular alterations important for this transition, we isolated human breast epithelial cell lines that showed partial loss of tissue polarity in three-dimensional reconstituted-basement membrane cultures. These cells remained non-invasive; however, unlike their non-malignant counterparts, they exhibited a high propensity to acquire invasiveness through basement membrane in culture. The genomic aberrations and gene expression profiles of the cells in this model showed a high degree of similarity to primary breast tumor profiles. The xenograft tumors formed by the cell lines in three different microenvironments in nude mice displayed metaplastic phenotypes, including squamous and basal characteristics, with invasive cells exhibiting features of higher grade tumors. To find functionally significant changes in transition from pre-invasive to invasive phenotype, we performed attribute profile clustering analysis on the list of genes differentially expressed between pre-invasive and invasive cells. We found integral membrane proteins, transcription factors, kinases, transport molecules, and chemokines to be highly represented. In addition, expression of matrix metalloproteinases MMP-9,-13,-15,-17 was up regulated …
Date: March 10, 2008
Creator: Bissell, Mina J; Rizki, Aylin; Weaver, Valerie M.; Lee, Sun-Young; Rozenberg, Gabriela I.; Chin, Koei et al.
Object Type: Article
System: The UNT Digital Library
Integrated Status and Effectiveness Monitoring Program, Entiat River Status and Trend Snorkel Surveys and Rotary Smolt Trap Operations in Nason Creek, March 2007 through March 2008. (open access)

Integrated Status and Effectiveness Monitoring Program, Entiat River Status and Trend Snorkel Surveys and Rotary Smolt Trap Operations in Nason Creek, March 2007 through March 2008.

The Integrated Status and Effectiveness Monitoring Program (ISEMP-BPA project No.2003-0017) has been created as a cost effective means of developing protocols and new technologies, novel indicators, sample designs, analytical, data management and communication tools and skills, and restoration experiments that support the development of a region-wide Research, Monitoring and Evaluation (RME) program to assess the status of anadromous salmonid populations, their tributary habitat and restoration and management actions. The most straightforward approach to developing a regional-scale monitoring and evaluation program would be to increase standardization among status and trend monitoring programs. However, the diversity of species and their habitat, as well as the overwhelming uncertainty surrounding indicators, metrics, and data interpretation methods, requires the testing of multiple approaches. Thus, the approach ISEMP has adopted is to develop a broad template that may differ in the details among subbasins, but one that will ultimately lead to the formation of a unified RME process for the management of anadromous salmonid populations and habitat across the Columbia River Basin. ISEMP has been initiated in three pilot subbasins, the Wenatchee/Entiat, John Day, and Salmon. To balance replicating experimental approaches with the goal of developing monitoring and evaluation tools that apply as broadly as possible …
Date: March 10, 2008
Creator: Collins, Matthew; Jorgensen, John & Murdock, Keely
Object Type: Report
System: The UNT Digital Library