Restoring Sustainable Forests on Appalachian Mined Lands for Wood Products, Renewable Energy, Carbon Sequestration, and Other Ecosystems Services Quarterly Report (open access)

Restoring Sustainable Forests on Appalachian Mined Lands for Wood Products, Renewable Energy, Carbon Sequestration, and Other Ecosystems Services Quarterly Report

The overall purpose of this project is to evaluate the biological and economic feasibility of restoring high-quality forests on mined land, and to measure carbon sequestration and wood production benefits that would be achieved from forest restoration procedures. In this segment of work, our goal was to review methods for estimating tree survival, growth, yield and value of forests growing on surface mined land in the eastern coalfields of the USA, and to determine the extent to which carbon sequestration is influenced by these factors. Public Law 95-87, the Surface Mining Control and Reclamation Act of 1977 (SMCRA), mandates that mined land be reclaimed in a fashion that renders the land at least as productive after mining as it was before mining. In the central Appalachian region, where prime farmland and economic development opportunities for mined land are scarce, the most practical land use choices are hayland/pasture, wildlife habitat, or forest land. Since 1977, the majority of mined land has been reclaimed as hayland/pasture or wildlife habitat, which is less expensive to reclaim than forest land, since there are no tree planting costs. As a result, there are now hundreds of thousands of hectares of grasslands and scrublands in various …
Date: December 15, 2003
Creator: Aggett, Jonathan
Object Type: Report
System: The UNT Digital Library
Neutrino telescopes as a direct probe of supersymmetrybreaking (open access)

Neutrino telescopes as a direct probe of supersymmetrybreaking

We consider supersymmetric models where the scale of supersymmetry breaking lies between 5 x 10{sup 6} GeV and 5 x 10{sup 8} GeV. In this class of theories, which includes models of gauge mediated supersymmetry breaking, the lightest supersymmetric particle is the gravitino. The next to lightest supersymmetric particle is typically a long lived charged slepton with a lifetime between a microsecond and a second, depending on its mass. Collisions of high energy neutrinos with nucleons in the earth can result in the production of a pair of these sleptons. Their very high boost means they typically decay outside the earth. We investigate the production of these particles by the diffuse flux of high energy neutrinos, and the potential for their observation in large ice or water Cerenkov detectors. The relatively small cross-section for the production of supersymmetric particles is partially compensated for by the very long range of heavy particles. The signal in the detector consists of two parallel charged tracks emerging from the earth about 100 meters apart, with very little background. A detailed calculation using the Waxman-Bahcall limit on the neutrino flux and realistic spectra shows that km{sup 3} experiments could see as many as 4 events …
Date: December 15, 2003
Creator: Albuquerque, Ivone; Burdman, Gustavo & Chacko, Z.
Object Type: Article
System: The UNT Digital Library
Physics of arcing, and implications to sputter deposition (open access)

Physics of arcing, and implications to sputter deposition

Arcing is a well-known, unwanted discharge regime observed on the surface of sputtering targets. The discharge voltage breaks down to less than 50 V while the current jumps to elevated levels. Arcing is unwanted because it prevents uniform deposition and creates particulates. The issue of arcing has been dealt with by target surface conditioning and by using modern power supplies that have arc suppression incorporated. With increasing quality requirements in terms of uniformity of coatings, and absence of particulates, especially for electrochromic and other advanced coatings applications, the issue of arcing warrants a closer examination with the goal to find other, physics-based, and hopefully better approaches of arcing prevention. From a physics point of view, the onset of arcing is nothing else than the transition of the discharge to a cathodic arc mode, which is characterized by the ignition of non-stationary arc spots. Arc spots operate by a sequence of microexplosions, enabling explosive electron emission, as opposed to secondary electron emission. Arc spots and their fragments have a size distribution in the micrometer and sub-micrometer range, and a characteristic time distribution that has components shorter than microseconds. Understanding the ignition conditions of arc spots are of central physical interest. Spot …
Date: December 15, 2003
Creator: Anders, Andre
Object Type: Article
System: The UNT Digital Library
Regional Heat Sources and the Active and Break Phases of Boreal Summer Intraseasonal Variability (open access)

Regional Heat Sources and the Active and Break Phases of Boreal Summer Intraseasonal Variability

The boreal summer intraseasonal variability (BSISV) associated with the 30-50 day mode is represented by the co-existence of three components, poleward propagation of convection over the Indian and tropical west Pacific longitudes and eastward propagation along the equator. The hypothesis that the three components influence each other has been investigated using observed OLR, NCEP-NCAR reanalysis, and solutions from an idealized linear model. The null hypothesis is that the three components are mutually independent. Cyclostationary EOF (CsEOF) analysis is applied on filtered OLR to extract the life-cycle of the BSISV. The dominant mode of CsEOF is significantly tied to observed rainfall over the Indian subcontinent. The components of the heating patterns from CsEOF analysis serve as prescribed forcings for the linear model. This allows us to ascertain which heat sources and sinks are instrumental in driving the large-scale monsoon circulation during the BSISV life-cycle. We identify three new findings: (1) the circulation anomalies that develop as a Rossby wave response to suppressed convection over the equatorial Indian Ocean associated with the previous break phase of the BSISV precondition the ocean-atmosphere system in the western Indian Ocean and trigger the next active phase of the BSISV, (2) the development of convection over …
Date: December 15, 2003
Creator: Annamalai, H & Sperber, K R
Object Type: Article
System: The UNT Digital Library
New Security Results on Encrypted Key Exchange (open access)

New Security Results on Encrypted Key Exchange

Schemes for encrypted key exchange are designed to provide two entities communicating over a public network, and sharing a (short) password only, with a session key to be used to achieve data integrity and/or message confidentiality. An example of a very efficient and ''elegant'' scheme for encrypted key exchange considered for standardization by the IEEE P1363 Standard working group is AuthA. This scheme was conjectured secure when the symmetric-encryption primitive is instantiated via either a cipher that closely behaves like an ''ideal cipher,'' or a mask generation function that is the product of the message with a hash of the password. While the security of this scheme in the former case has been recently proven, the latter case was still an open problem. For the first time we prove in this paper that this scheme is secure under the assumptions that the hash function closely behaves like a random oracle and that the computational Diffie-Hellman problem is difficult. Furthermore, since Denial-of-Service (DoS) attacks have become a common threat we enhance AuthA with a mechanism to protect against them.
Date: December 15, 2003
Creator: Bresson, Emmanuel; Chevassut, Olivier & Pointcheval, David
Object Type: Article
System: The UNT Digital Library
Solution Sythesis Of Geranium Nanocrystals: Success And Open Challenges (open access)

Solution Sythesis Of Geranium Nanocrystals: Success And Open Challenges

We present a two-steps synthesis route that yields nanometer size crystalline germanium in the form of a black powder. It relies on high temperature decomposition of tetraethylgermane (TEG) in organic solvents. The presence of pure germanium with diamond structure is unambiguously attested by powder XRD measurements. Low resolution TEM indicates that the particles are between {approx}5 to 30 nm in size depending on the synthesis conditions. The as-synthesized Ge powders can be stored in air for months and no oxidation occurs. The Ge powders are sparingly soluble in conventional solvents because Ge nanocrystals are likely embedded in a matrix, composed mainly of C=C, C-C, and C-H bonds. The presence of residual organic by-products impedes probing of the optical properties of the dots. Also, we discuss drawbacks and open challenges in high temperature solution synthesis of Ge nanocrystals that could also be faced in the synthesis of Si nanocrystals. Overall, our results call for a cautious interpretation of reported optical properties of Ge and Si nanocrystals obtained by high temperature solution methods.
Date: December 15, 2003
Creator: Casula, M; Galli, G; Saw, C; Zaitseva, N; Gerion, D; van Buuren, T et al.
Object Type: Article
System: The UNT Digital Library
CHEMICAL FIXATION OF CO2 IN COAL COMBUSTION PRODUCTS AND RECYCLING THROUGH BIOSYSTEMS (open access)

CHEMICAL FIXATION OF CO2 IN COAL COMBUSTION PRODUCTS AND RECYCLING THROUGH BIOSYSTEMS

This Annual Technical Progress Report presents the principle results in enhanced growth of algae using coal combustion products as a catalyst to increase bicarbonate levels in solution. A co-current reactor is present that increases the gas phase to bicarbonate transfer rate by a factor of five to nine. The bicarbonate concentration at a given pH is approximately double that obtained using a control column of similar construction. Algae growth experiments were performed under laboratory conditions to obtain baseline production rates and to perfect experimental methods. The final product of this initial phase in algae production is presented. Algal growth can be limited by several factors, including the level of bicarbonate available for photosynthesis, the pH of the growth solution, nutrient levels, and the size of the cell population, which determines the available space for additional growth. In order to supply additional CO2 to increase photosynthesis and algal biomass production, fly ash reactor has been demonstrated to increase the available CO2 in solution above the limits that are achievable with dissolved gas alone. The amount of dissolved CO2 can be used to control pH for optimum growth. Periodic harvesting of algae can be used to maintain algae in the exponential, rapid …
Date: December 15, 2003
Creator: Copeland, C. Henry; Pier, Paul; Whitehead, Samantha; Enlow, Paul; Strickland, Richard & Behel, David
Object Type: Report
System: The UNT Digital Library
Characterization of DWPF Melter One Glasses (open access)

Characterization of DWPF Melter One Glasses

The Defense Waste Processing Facility's first melter operated continuously for more than eight years. In November 2002 it was decided to replace the melter. As part of the decommissioning and replacement of the first DWPF melter, three samples were collected from the melter, one from the melter surface and two from the core sampler. The melter samples were analyzed for chemical composition and crystal content.
Date: December 15, 2003
Creator: Cozzi, A.D.
Object Type: Report
System: The UNT Digital Library
Conservation Research and Development/ New Ultra-Low Carbon High Strength Steels with Improved Bake Hardenability for Enhanced Stretch Formability and Dent Resistance (open access)

Conservation Research and Development/ New Ultra-Low Carbon High Strength Steels with Improved Bake Hardenability for Enhanced Stretch Formability and Dent Resistance

Conservation Research and Development/New Ultra-Low Carbon High Strength Steels with Improved Bake Hardenability for Enhanced Stretch Formability and Dent Resistance. The experimental work can be divided into four phases. In each phase, the materials were received or designed, processed and tested, to evaluate the BH increment or response, as a function of compositions and processing conditions. Microstructural characterization by various techniques was performed in order to gain insights into the mechanisms of flow stress increment by bake hardening.
Date: December 15, 2003
Creator: DeArdo, Anthony J. & Garcia, C. Isaac
Object Type: Report
System: The UNT Digital Library
Natural Strontium, Iodine, Cesium, and Cobalt in Savannah River Site Groundwater: Data Report (open access)

Natural Strontium, Iodine, Cesium, and Cobalt in Savannah River Site Groundwater: Data Report

The purpose of this investigation was to obtain baseline groundwater concentrations for naturally occurring stable isotopes of Sr, I, Cs, and Co in shallow aquifers at the Savannah River Site. These data are necessary to fully understand migration and remediation of 90Sr, 129I, 137Cs, and 60Co. Fourteen P-wells were selected and sampled based on their close proximity to facilities, available water table and Gordon aquifer wells, and archived core. This report provides the analytical results from the groundwater sampling and core leaching studies. Several radioactive contaminants have naturally occurring counterparts that are non-radioactive, but have chemical behavior that is identical to the radioactive contaminants. These naturally occurring isotopes are typically present in groundwater at mass concentrations that are orders of magnitude greater than their associated radionuclides. A consequence of this is that the natural constituents compete for adsorption and cation exchange site s with their radioactive counterparts, reducing retardation of the radioactive species. Hence, the concentrations of these natural species are important to the modeling of monitored natural attenuation, performance assessments, and other regulatory documents that require a fate and transport analysis.
Date: December 15, 2003
Creator: Denham, M.E.
Object Type: Report
System: The UNT Digital Library
Technology Transfer to U.S. Independent Oil and Natural Gas Producers: 2003 (open access)

Technology Transfer to U.S. Independent Oil and Natural Gas Producers: 2003

The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of assisting U.S. independent oil and gas producers to make timely, informed technology decisions. Functioning as a cohesive national organization, PTTC has active grassroots programs through its 10 Regional Lead Organizations (RLOs) and 3 Satellite Offices that encompass all of the oil- and natural gas-producing regions in the U.S. Active volunteer leadership from the Board and regional Producer Advisory Groups keeps activities focused on producer's needs. Technical expertise and personal networks of national and regional staff enable PTTC to deliver focused, technology-related information in a manner that is cost and time effective for independents. The organization effectively combines federal funding through the Department of Energy's (DOE) Office of Fossil Energy with matching state and industry funding, forming a unique partnership. This final report summarizes PTTC's accomplishments. In this final fiscal year of the contract, activities exceeded prior annual activity levels by significant percentages. Strategic planning implemented during the year is focusing PTTC's attention on changes that will bear fruit in the future. Networking and connections are increasing PTTC's sphere of influence with both producers and the service sector. PTTC's reputation for unbiased bottom-line information stimulates cooperative ventures. In FY03 PTTC's …
Date: December 15, 2003
Creator: Duttlinger, Donald F. & Cole, E. Lance
Object Type: Report
System: The UNT Digital Library
Detection of aerosolized biological agents by immunoassay followed by autonomous PCR confirmation (open access)

Detection of aerosolized biological agents by immunoassay followed by autonomous PCR confirmation

An Autonomous Pathogen Detection System (APDS) unit is an automated, podium-sized system that monitors the air for all three biological threat agents (bacteria, viruses, and toxins). The system has been developed under the auspices of the U. S. Department of Energy and Department of Homeland Security by the University of California, Lawrence Livermore National Laboratory (LLNL) to protect people in critical or high-traffic facilities and at special events. The system performs continuous aerosol collection, sample preparation, and multiplexed biological tests using advanced immunoassays as the primary screen. Over ten agents are assayed at once, and results are reported hourly. R&D work this year focused on incorporating polymerase chain-reaction (PCR) techniques for detecting DNA as confirmation of immunoassay positives. The primary objective of the Dugway testing was to demonstrate the APDS with immunoassay identification and PCR confirmation of bacteria. A secondary objective was to demonstrate immunoassay identification of a protein toxoid (denatured toxin) aerosol release. A total of 12 agent trials were conducted over 14 days of testing, for a total of four work weeks at Dugway. Both testing objectives were achieved with multiple releases and clear identifications. The APDS was shown to be effective for identifying aerosolized Bacillus anthracis, Yersinia …
Date: December 15, 2003
Creator: Dzenitis, John M.; Hindson, Benjamin J.; McBride, Mary T.; Makarewicz, Anthony J.; Henderer, Bruce D.; Sathyam, Ujwal S. et al.
Object Type: Report
System: The UNT Digital Library
Environmentally Benign Stab Detonators (open access)

Environmentally Benign Stab Detonators

This effort attempts to demonstrate that environmentally acceptable energetic sol-gel coated flash metal multilayer nanocomposites can be used to replace current impact initiated devices (IIDs) which have hazardous and toxic components. Successful completion of this project will result in IIDs that include innocuous compounds, have sufficient output energy for initiation, meet current military specifications, are small, cost competitive, and perform as well as or better than current devices. We expect flash metal multilayer and sol-gel to be generic technologies applicable to a wide range of devices, especially in small caliber ammunition and sub-munitions. We will replace the NOL-130 mixture with a nanocomposite that consists of a mechanically robust energetic multilayer foil that has been coated with a sol-gel energetic material. The exothermic reactions are activated in this nanocomposite are the transformation of the multilayer material to its respective intermetallic alloy and the thermite reaction, which is characterized by very high temperatures, a small pressure pulse, and hot particle ejection. The proposed materials and their reaction products consist of, but are not limited to aluminum, nickel, iron, aluminum oxide, titanium, iron oxide and boron. These materials have much more desirable environmental and health characteristics than the NOL-130 composition.
Date: December 15, 2003
Creator: Gash, A.; Barbee, T.; Simpson, R.; Satcher, J. & Walton, C.
Object Type: Report
System: The UNT Digital Library
Atmospheric-Pressure Plasma Cleaning of Contaminated Surfaces (open access)

Atmospheric-Pressure Plasma Cleaning of Contaminated Surfaces

The purpose of this project was to demonstrate a practical, environmentally benigh technology for the surface decontamination and decommissioning of radioactive waste. A low temperature, atmospheric pressure plasma has been developed with initial support from the DOE, Environmental Management Sciences Program. This devise selectively etches radioactive metals from surfaces, rendering objects radiation free and suitable for decommissioning. The volatile reaction products are captured on filters, which yields a tremendous reduction in the volume of the waste. The technology shows a great potential for accelerating the clean-up effort for the equipment and structures contaminated with radioactive materials within the DOE complex. The viability of this technology has been demonstrated by selectively and rapidly stripping uranium from stainless steel surfaces at low temperature. Studies on uranium oxide have shown that etch rates of 4.0 microns per minute can be achieved at temperature below 473 K. Over the past three years, we have made numerous improvements in the design of the atmospheric pressure plasma source. We are now able to scale up the plasma source to treat large surface areas.
Date: December 15, 2003
Creator: Hicks, Robert F. & Herrmann, Hans W.
Object Type: Report
System: The UNT Digital Library
Past, present and future highlights in top and higgs physics from the CDF experiment (open access)

Past, present and future highlights in top and higgs physics from the CDF experiment

The 1992-1995 running of the Fermilab Tevatron (the so-called Run 1) ended with many important physics goals accomplished, including the discovery of the top quark, and the anticipation of many further questions be to answered in the future. In March 2002, after many detector upgrades by both the CDF and D0 experiments, and significant upgrades of the accelerator itself, the Tevatron Run 2 began (after a detector commissioning run) with the ultimate goal of discovering the Higgs boson. Here, we will highlight some important Run 1 results from CDF in the areas of top quark and Higgs boson physics, show some preliminary studies from Run 2, and give some expectations of what Run 2 will ultimately provide to our understanding of matter.
Date: December 15, 2003
Creator: Kruse, M. C.
Object Type: Article
System: The UNT Digital Library
PLEIADES: High Peak Brightness, Subpicosecond Thomson Hard-X-ray source (open access)

PLEIADES: High Peak Brightness, Subpicosecond Thomson Hard-X-ray source

The Picosecond Laser-Electron Inter-Action for the Dynamic Evaluation of Structures (PLEIADES) facility, is a unique, novel, tunable (10-200 keV), ultrafast (ps-fs), hard x-ray source that greatly extends the parameter range reached by existing 3rd generation sources, both in terms of x-ray energy range, pulse duration, and peak brightness at high energies. First light was observed at 70 keV early in 2003, and the experimental data agrees with 3D codes developed at LLNL. The x-rays are generated by the interaction of a 50 fs Fourier-transform-limited laser pulse produced by the TW-class FALCON CPA laser and a highly focused, relativistic (20-100 MeV), high brightness (1 nC, 0.3-5 ps, 5 mm.mrad, 0.2% energy spread) photo-electron bunch. The resulting x-ray brightness is expected to exceed 10{sup 20} ph/mm{sup 2}/s/mrad{sup 2}/0.1% BW. The beam is well-collimated (10 mrad divergence over the full spectrum, 1 mrad for a single color), and the source is a unique tool for time-resolved dynamic measurements in matter, including high-Z materials.
Date: December 15, 2003
Creator: Kuba, J.; Anderson, S. G.; Barty, C. J.; Betts, S. M.; Booth, R.; Brown, W. J. et al.
Object Type: Article
System: The UNT Digital Library
Grout Placement and Property Evaluation for Closing Hanford High-Level Waste Tanks - Scale-Up Testing (open access)

Grout Placement and Property Evaluation for Closing Hanford High-Level Waste Tanks - Scale-Up Testing

Hanford has 149 single-shell high level waste (HLW) tanks that were constructed between 1943 and 1964. Many of these tanks have leaked or are suspected of leaking HLW into the soil above the ground water. Consequently, a major effort is ongoing to transfer the liquid portion of the waste to the 28 newer, double-shell tanks. Savannah River National Laboratory (SRNL) was tasked to develop grout formulations for the three-layer closure concept selected by CH2M HILL for closing Tank C-106. These grout formulations were also evaluated for use as fill materials in the next six tanks scheduled to be closed. The overall scope consisted of both bench-scale testing to confirm mix designs and scale-up testing to confirm placement properties. This report provides results of the scale-up testing for the three-phase tank closure strategy. It also contains information on grouts for equipment and riser filling. The three-phase fill strategy is summarized as follows: Phase I fill encapsulates and minimizes dispersion of the residual waste in the tank. This fill is referred to as the Stabilization Layer and consists of the Stabilization Grout. The Phase II fill provides structural stability to the tank system and prevents subsidence. It is referred to as the …
Date: December 15, 2003
Creator: LANGTON, CHRISTINE
Object Type: Report
System: The UNT Digital Library
Jet Physics at Tevatron (open access)

Jet Physics at Tevatron

An overview of Run I jet physics at the p{bar p} Fermilab Tevatron Collider with a particular emphasis on inclusive jet cross section measurements is given. The impact of these studies on PDFs constrain from global fits is underlined. Preliminary results on inclusive jet and di-jet mass cross section measurements in Run II are then summarized.
Date: December 15, 2003
Creator: Latino, G.
Object Type: Article
System: The UNT Digital Library
Nitrogen doped zinc oxide thin film (open access)

Nitrogen doped zinc oxide thin film

To summarize, polycrystalline ZnO thin films were grown by reactive sputtering. Nitrogen was introduced into the films by reactive sputtering in an NO{sub 2} plasma or by N{sup +} implantation. All ZnO films grown show n-type conductivity. In unintentionally doped ZnO films, the n-type conductivities are attributed to Zn{sub i}, a native shallow donor. In NO{sub 2}-grown ZnO films, the n-type conductivity is attributed to (N{sub 2}){sub O}, a shallow double donor. In NO{sub 2}-grown ZnO films, 0.3 atomic % nitrogen was found to exist in the form of N{sub 2}O and N{sub 2}. Upon annealing, N{sub 2}O decomposes into N{sub 2} and O{sub 2}. In furnace-annealed samples N{sub 2} redistributes diffusively and forms gaseous N{sub 2} bubbles in the films. Unintentionally doped ZnO films were grown at different oxygen partial pressures. Zni was found to form even at oxygen-rich condition and led to n-type conductivity. N{sup +} implantation into unintentionally doped ZnO film deteriorates the crystallinity and optical properties and leads to higher electron concentration. The free electrons in the implanted films are attributed to the defects introduced by implantation and formation of (N{sub 2}){sub O} and Zni. Although today there is still no reliable means to produce good …
Date: December 15, 2003
Creator: Li, Sonny X.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Methods to model-check parallel systems software. (open access)

Methods to model-check parallel systems software.

We report on an effort to develop methodologies for formal verification of parts of the Multi-Purpose Daemon (MPD) parallel process management system. MPD is a distributed collection of communicating processes. While the individual components of the collection execute simple algorithms, their interaction leads to unexpected errors that are difficult to uncover by conventional means. Two verification approaches are discussed here: the standard model checking approach using the software model checker SPIN and the nonstandard use of a general-purpose first-order resolution-style theorem prover OTTER to conduct the traditional state space exploration. We compare modeling methodology and analyze performance and scalability of the two methods with respect to verification of MPD.
Date: December 15, 2003
Creator: Matlin, O. S.; McCune, W. & Lusk, E.
Object Type: Report
System: The UNT Digital Library
Report on the Power and Detector Stability Measurements for the QC Laser Alignment System (open access)

Report on the Power and Detector Stability Measurements for the QC Laser Alignment System

This report summarizes the preliminary tests that PNNL has performed to date for the Quantum Cascade (QC) Laser Alignment System that is being developed for the Using Client for a classified application. PNNL is designing, fabricating, assembling, and testing the QC Laser Alignment System and has a subcontract with Maxion Technologies, Inc. for development and production of the QC laser devices to be used in this system. The QC lasers furnished by Maxion will be incorporated into the QC Laser Alignment System by PNNL. The QC Laser Alignment System consists of five Alignment Source Assemblies (ASAs) and a computer control system with graphical user interface (GUI). Each ASA has two QC lasers along with a temperature sensor. The system design also includes an optical detector for each QC laser to measure the output power of the rear facet for additional stabilization. The system will monitor the voltage across the QC laser, the temperature, the current, and the signal from the optical detectors to ensure the system is within the tolerances specified in the System Specifications. The System Specifications require that the relative power between lasers on the same ASA be maintained at {+-}1% and among the lasers on different ASAs …
Date: December 15, 2003
Creator: Myers, Tanya L.; Bonebrake, Christopher A.; Cannon, Bret D.; Suarez, Reynold; Stewart, Timothy L. & Hatchell, Brian K.
Object Type: Report
System: The UNT Digital Library
A Numerical Algorithm for Complex Biological Flow in Irregular Microdevice Geometries (open access)

A Numerical Algorithm for Complex Biological Flow in Irregular Microdevice Geometries

We present a numerical algorithm to simulate non-Newtonian flow in complex microdevice components. The model consists of continuum viscoelastic incompressible flow in irregular microscale geometries. Our numerical approach is the projection method of Bell, Colella and Glaz (BCG) to impose the incompressibility constraint coupled with the polymeric stress splitting discretization of Trebotich, Colella and Miller (TCM). In this approach we exploit the hyperbolic structure of the equations of motion to achieve higher resolution in the presence of strong gradients and to gain an order of magnitude in the timestep. We also extend BCG and TCM to an embedded boundary method to treat irregular domain geometries which exist in microdevices. Our method allows for particle representation in a continuum fluid. We present preliminary results for incompressible viscous flow with comparison to flow of DNA and simulants in microchannels and other components used in chem/bio microdevices.
Date: December 15, 2003
Creator: Nonaka, A; Miller, G H; Marshall, T; Liepmann, D; Gulati, S; Trebotich, D et al.
Object Type: Article
System: The UNT Digital Library
STOPLIGHT CHARTS (WITH SPC INSIDE) (open access)

STOPLIGHT CHARTS (WITH SPC INSIDE)

None
Date: December 15, 2003
Creator: Prevette, S. S.
Object Type: Article
System: The UNT Digital Library
Field Performance of a Slimline Turbomist Evaporator under Southeastern U. S. Climate Conditions (open access)

Field Performance of a Slimline Turbomist Evaporator under Southeastern U. S. Climate Conditions

A recent study of evaporation technologies for treating F- and H-area groundwater contaminated with radionuclides and metals (Flach 2002) suggested that spray evaporation might be a viable alternative or supplemental technique for managing tritiated groundwater at the Mixed Waste Management Facility. The particular technology of interest in this study is the Slimline Manufacturing Ltd. Turbo-Mist Evaporator, which uses a powerful blower and high-pressure spray nozzles to propel a fine mist into the air at high air and water flowrates.
Date: December 15, 2003
Creator: Sappington, F.C.
Object Type: Report
System: The UNT Digital Library