Dynamics of Arctic and Sub-Arctic Climate and Atmospheric Circulation: Diagnosis of Mechanisms and Biases Using Data Assimilation (open access)

Dynamics of Arctic and Sub-Arctic Climate and Atmospheric Circulation: Diagnosis of Mechanisms and Biases Using Data Assimilation

The overall goal of work performed under this grant is to enhance understanding of simulations of present-day climate and greenhouse gas-induced climate change. The examination of present-day climate also includes diagnostic intercomparison of model simulations and observed mean climate and climate variability using reanalysis and satellite datasets. Enhanced understanding is desirable 1) as a prerequisite for improving simulations; 2) for assessing the credibility of model simulations and their usefulness as tools for decision support; and 3) as a means to identify robust behaviors which commonly occur over a wide range of models, and may yield insights regarding the dominant physical mechanisms which determine mean climate and produce climate change. A further objective is to investigate the use of data assimilation as a means for examining and correcting model biases. Our primary focus is on the Arctic, but the scope of the work was expanded to include the global climate system.
Date: February 17, 2010
Creator: DeWeaver, Eric T.
Object Type: Report
System: The UNT Digital Library
Geothermal Energy for New Mexico: Assessment of Potential and Exploratory Drilling (open access)

Geothermal Energy for New Mexico: Assessment of Potential and Exploratory Drilling

This report summarizes the drilling operations and subsequent interpretation of thermal and geochemical data from the New Mexico Tech NMT-2GT (OSE RG- 05276 POD) test well. This slim hole was drilled along an elongate heat-flow anomaly at the base of the Socorro Mountains to better assess the geothermal resource potential (Socorro Peak geothermal system) on the western side of the New Mexico Tech campus in Socorro, New Mexico. The reservoir depth, hydraulic properties, temperature and chemistry were unknown prior to drilling. The purpose of the NMT-2GT (OSE RG-05276 POD) well was to explore the feasibility of providing geothermal fluids for a proposed district space heating system on the New Mexico Tech campus. With DOE cost over runs funds we completed NMT-2GT to a depth of 1102 feet at the Woods Tunnel drill site. Temperatures were nearly constant (41 oC ) between a depth of 400–1102 feet. Above this isothermal zone, a strong temperature gradient was observed (210 oC /km) beneath the water table consistent with vertical convective heat transfer. The existence of a groundwater upflow zone was further supported by measured vertical hydraulic head measurements which varied between about 258 feet at the water table to 155 feet at a …
Date: February 17, 2010
Creator: Mark Person, Lara Owens, James Witcher
Object Type: Report
System: The UNT Digital Library
NW-MILO Acoustic Data Collection (open access)

NW-MILO Acoustic Data Collection

There is an enduring requirement to improve our ability to detect potential threats and discriminate these from the legitimate commercial and recreational activity ongoing in the nearshore/littoral portion of the maritime domain. The Northwest Maritime Information and Littoral Operations (NW-MILO) Program at PNNL’s Coastal Security Institute in Sequim, Washington is establishing a methodology to detect and classify these threats - in part through developing a better understanding of acoustic signatures in a near-shore environment. The purpose of the acoustic data collection described here is to investigate the acoustic signatures of small vessels. The data is being recorded continuously, 24 hours a day, along with radar track data and imagery. The recording began in August 2008, and to date the data contains tens of thousands of signals from small vessels recorded in a variety of environmental conditions. The quantity and variety of this data collection, with the supporting imagery and radar track data, makes it particularly useful for the development of robust acoustic signature models and advanced algorithms for signal classification and information extraction. The underwater acoustic sensing system is part of a multi-modal sensing system that is operating near the mouth of Sequim Bay. Sequim Bay opens onto the Straight …
Date: February 17, 2010
Creator: Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R. & Jones, Mark E.
Object Type: Report
System: The UNT Digital Library
Optimization of azimuthal uniformity of thermal conductance between AI TMP and Si cooling arms (open access)

Optimization of azimuthal uniformity of thermal conductance between AI TMP and Si cooling arms

None
Date: February 17, 2010
Creator: Bhandarkar, S D; Mapoles, E A; Kroll, J J; Taylor, J S; Haid, B; Sater, J D et al.
Object Type: Article
System: The UNT Digital Library
THE POSITIVE IMPACTS OF ARRA (AMERICAN REINVESTMENT AND RECOVERY ACT) FUNDING TO THE WASTE MANAGEMENT PROGRAM ON HANFORD'S PLATEAU REMEDIATION PROJECT (open access)

THE POSITIVE IMPACTS OF ARRA (AMERICAN REINVESTMENT AND RECOVERY ACT) FUNDING TO THE WASTE MANAGEMENT PROGRAM ON HANFORD'S PLATEAU REMEDIATION PROJECT

None
Date: February 17, 2010
Creator: LT, BLACKFORD
Object Type: Article
System: The UNT Digital Library
Precision Engineering within the National Ignition Campaign (open access)

Precision Engineering within the National Ignition Campaign

In this very brief talk, we'll discuss how precision engineering impacts 4 key areas of NIF: (1) Diamond turning of KDP crystals; (2) Mitigation of laser damage on optics; (3) Alignment of lasers, targets, diagnostics; (4) Target fabrication.
Date: February 17, 2010
Creator: Taylor, J S; Carlisle, K; Klingmann, J L; Geraghty, P; Saito, T T & Montesanti, R C
Object Type: Article
System: The UNT Digital Library
Accounting for Global Climate Model Projection Uncertainty in Modern Statistical Downscaling (open access)

Accounting for Global Climate Model Projection Uncertainty in Modern Statistical Downscaling

Future climate change has emerged as a national and a global security threat. To carry out the needed adaptation and mitigation steps, a quantification of the expected level of climate change is needed, both at the global and the regional scale; in the end, the impact of climate change is felt at the local/regional level. An important part of such climate change assessment is uncertainty quantification. Decision and policy makers are not only interested in 'best guesses' of expected climate change, but rather probabilistic quantification (e.g., Rougier, 2007). For example, consider the following question: What is the probability that the average summer temperature will increase by at least 4 C in region R if global CO{sub 2} emission increases by P% from current levels by time T? It is a simple question, but one that remains very difficult to answer. It is answering these kind of questions that is the focus of this effort. The uncertainty associated with future climate change can be attributed to three major factors: (1) Uncertainty about future emission of green house gasses (GHG). (2) Given a future GHG emission scenario, what is its impact on the global climate? (3) Given a particular evolution of the …
Date: March 17, 2010
Creator: Johannesson, G
Object Type: Report
System: The UNT Digital Library
CO2 MONITORING FOR DEMAND CONTROLLED VENTILATION IN COMMERCIAL BUILDINGS (open access)

CO2 MONITORING FOR DEMAND CONTROLLED VENTILATION IN COMMERCIAL BUILDINGS

Carbon dioxide (CO{sub 2}) sensors are often deployed in commercial buildings to obtain CO{sub 2} data that are used, in a process called demand-controlled ventilation, to automatically modulate rates of outdoor air ventilation. The objective is to keep ventilation rates at or above design specifications and code requirements and also to save energy by avoiding excessive ventilation rates. Demand controlled ventilation is most often used in spaces with highly variable and sometime dense occupancy. Reasonably accurate CO{sub 2} measurements are needed for successful demand controlled ventilation; however, prior research has suggested substantial measurement errors. Accordingly, this study evaluated: (a) the accuracy of 208 CO{sub 2} single-location sensors located in 34 commercial buildings, (b) the accuracy of four multi-location CO{sub 2} measurement systems that utilize tubing, valves, and pumps to measure at multiple locations with single CO{sub 2} sensors, and (c) the spatial variability of CO{sub 2} concentrations within meeting rooms. The field studies of the accuracy of single-location CO{sub 2} sensors included multi-concentration calibration checks of 90 sensors in which sensor accuracy was checked at multiple CO{sub 2} concentrations using primary standard calibration gases. From these evaluations, average errors were small, -26 ppm and -9 ppm at 760 and 1010 …
Date: March 17, 2010
Creator: Fisk, William J.; Sullivan, Douglas P.; Faulkner, David & Eliseeva, Ekaterina
Object Type: Report
System: The UNT Digital Library
A Comparison of Three Voting Methods for Bagging with the MLEM2 Algorithm (open access)

A Comparison of Three Voting Methods for Bagging with the MLEM2 Algorithm

This paper presents results of experiments on some data sets using bagging on the MLEM2 rule induction algorithm. Three different methods of ensemble voting, based on support (a non-democratic voting in which ensembles vote with their strengths), strength only (an ensemble with the largest strength decides to which concept a case belongs) and democratic voting (each ensemble has at most one vote) were used. Our conclusions are that though in most cases democratic voting was the best, it is not significantly better than voting based on support. The strength voting was the worst voting method.
Date: March 17, 2010
Creator: Cohagan, Clinton; Grzymala-Busse, Jerzy W. & Hippe, Zdzislaw S.
Object Type: Article
System: The UNT Digital Library
Final Report for "Verification and Validation of Radiation Hydrodynamics for Astrophysical Applications" (open access)

Final Report for "Verification and Validation of Radiation Hydrodynamics for Astrophysical Applications"

The motivation for this work is to gain experience in the methodology of verification and validation (V&V) of astrophysical radiation hydrodynamics codes. In the first period of this work, we focused on building the infrastructure to test a single astrophysical application code, Castro, developed in collaboration between Lawrence Livermore National Laboratory (LLNL) and Lawrence Berkeley Laboratory (LBL). We delivered several hydrodynamic test problems, in the form of coded initial conditions and documentation for verification, routines to perform data analysis, and a generalized regression test suite to allow for continued automated testing. Astrophysical simulation codes aim to model phenomena that elude direct experimentation. Our only direct information about these systems comes from what we observe, and may be transient. Simulation can help further our understanding by allowing virtual experimentation of these systems. However, to have confidence in our simulations requires us to have confidence in the tools we use. Verification and Validation is a process by which we work to build confidence that a simulation code is accurately representing reality. V&V is a multistep process, and is never really complete. Once a single test problem is working as desired (i.e. that problem is verified), one wants to ensure that subsequent code …
Date: March 17, 2010
Creator: Zingale, M & Howell, L H
Object Type: Report
System: The UNT Digital Library
Northwest Open Automated Demand Response Technology Demonstration Project (open access)

Northwest Open Automated Demand Response Technology Demonstration Project

The Lawrence Berkeley National Laboratory (LBNL) Demand Response Research Center (DRRC) demonstrated and evaluated open automated demand response (OpenADR) communication infrastructure to reduce winter morning and summer afternoon peak electricity demand in commercial buildings the Seattle area. LBNL performed this demonstration for the Bonneville Power Administration (BPA) in the Seattle City Light (SCL) service territory at five sites: Seattle Municipal Tower, Seattle University, McKinstry, and two Target stores. This report describes the process and results of the demonstration. OpenADR is an information exchange model that uses a client-server architecture to automate demand-response (DR) programs. These field tests evaluated the feasibility of deploying fully automated DR during both winter and summer peak periods. DR savings were evaluated for several building systems and control strategies. This project studied DR during hot summer afternoons and cold winter mornings, both periods when electricity demand is typically high. This is the DRRC project team's first experience using automation for year-round DR resources and evaluating the flexibility of commercial buildings end-use loads to participate in DR in dual-peaking climates. The lessons learned contribute to understanding end-use loads that are suitable for dispatch at different times of the year. The project was funded by BPA and SCL. …
Date: March 17, 2010
Creator: Kiliccote, Sila; Piette, Mary Ann & Dudley, Junqiao
Object Type: Report
System: The UNT Digital Library
PACE and the Federal Housing Finance Agency (FHFA) (open access)

PACE and the Federal Housing Finance Agency (FHFA)

The FHFA regulates Fannie Mae, Freddie Mac, and the 12 Federal Home Loan Banks (the government-sponsored enterprises - GSEs). On June 18, 2009, James B. Lockhart III, then Director of FHFA, released a letter expressing concern about the negative impact of energy loan tax assessment programs (ELTAPs) - also known as Property Assessed Clean Energy (PACE) programs - on both the housing finance system and homeowner program participants. Subsequently, a number of PACE proponents responded to the concerns laid out in the FHFA letter. In early Fall 2009, word circulated that FHFA was planning to follow its June letter with guidance to other agencies, possibly including Fannie Mae and Freddie Mac, discouraging them from buying loans on properties subject to PACE-type assessment liens. This triggered a second round of stakeholder letters, several of which were addressed to President Obama. On October 18, 2009, the White House, in what some believe was an attempt to obviate the need for FHFA guidance, released a Policy Framework for PACE Financing Programs that outlined best practices guidance for homeowner and lender protection. As of February 2010, FHFA and the GSEs have agreed to monitor PACE programs and work with stakeholders and the Administration to …
Date: March 17, 2010
Creator: Zimring, Mark & Fuller, Merrian
Object Type: Report
System: The UNT Digital Library
Proceedings of RIKEN BNL Research Center Workshop: Progress in High-pT Physics at RHIC (open access)

Proceedings of RIKEN BNL Research Center Workshop: Progress in High-pT Physics at RHIC

This volume archives the presentations at the RIKEN BNL Research Center workshop 'Progress in High-PT Physics at RHIC', held at BNL in March 2010. Much has been learned from high-p{sub T} physics after 10 years of RHIC operations for heavy-ion collisions, polarized proton collisions and d+Au collisions. The workshop focused on recent progress in these areas by both theory and experiment. The first morning saw review talks on the theory of RHIC high-p{sub T} physics by G. Sterman and J. Soffer, and on the experimental results by M. Tannenbaum. One of the most exciting recent results from the RHIC spin program is the first observation of W bosons and their associated single-spin asymmetry. The new preliminary data were reported on the first day of our workshop, along with a theoretical perspective. There also were detailed discussions on the global analysis of polarized parton distributions, including the knowledge on gluon polarization and the impact of the W-data. The main topic of the second workshop day were single-transverse spin asymmetries and their analysis in terms of transverse-momentum dependent parton distributions. There is currently much interest in a future Drell-Yan program at RHIC, thanks to the exciting physics opportunities this would offer. This …
Date: March 17, 2010
Creator: Bazilevsky, A.; Bland, L. & Vogelsang, W.
Object Type: Report
System: The UNT Digital Library
X-ray source brightness comparison: Rigaku rotating anode source vs. Kevex microfocus tube (open access)

X-ray source brightness comparison: Rigaku rotating anode source vs. Kevex microfocus tube

In 2007, we began to explore alternative x-ray sources for application to refraction-enhanced (phase contrast) x-ray radiography of cryogenic NIF ignition capsules containing frozen deuterium-tritium (D-T) ice layers. These radiographs are currently obtained using Kevex microfocus tubes as backlights, and for these sources the x-ray source size is approximately 5 {micro}m. As part of this exploration, we obtained refraction-enhanced radiographs of empty plastic capsules using the Janus laser facility at LLNL, demonstrating that even large ({approx} 100 {micro}m) sources can be utilized in refraction-enhanced radiography provided the source/sample distance is sufficiently large, and provided the final x-ray detector has sufficient spatial resolution. Essentially, in the current geometry, we rely on a small source to provide spatial resolution and on the source/sample distance to provide refraction contrast, but an equally useful alternative geometry is to use a large source and rely on fine detector spatial resolution to provide spatial resolution and on the sample/detector distance to provide refraction contrast.
Date: March 17, 2010
Creator: Koch, J A; Dewald, E & Kozioziemski, B
Object Type: Report
System: The UNT Digital Library
Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens (open access)

Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens

The Biolog OmniLog? Phenotype MicroArray (PM) plate technology was successfully adapted to generate a select phenotypic profile of the strict anaerobe Geobacter metallireducens (G.m.). The profile generated for G.m. provides insight into the chemical sensitivity of the organism as well as some of its metabolic capabilities when grown with a basal medium containing acetate and Fe(III). The PM technology was developed for aerobic organisms. The reduction of a tetrazolium dye by the test organism represents metabolic activity on the array which is detected and measured by the OmniLog(R) system. We have previously adapted the technology for the anaerobic sulfate reducing bacterium Desulfovibrio vulgaris. In this work, we have taken the technology a step further by adapting it for the iron reducing obligate anaerobe Geobacter metallireducens. In an osmotic stress microarray it was determined that the organism has higher sensitivity to impermeable solutes 3-6percent KCl and 2-5percent NaNO3 that result in osmotic stress by osmosis to the cell than to permeable non-ionic solutes represented by 5-20percent ethylene glycol and 2-3percent urea. The osmotic stress microarray also includes an array of osmoprotectants and precursor molecules that were screened to identify substrates that would provide osmotic protection to NaCl stress. None of the …
Date: May 17, 2010
Creator: Joyner, Dominique; Fortney, Julian; Chakraborty, Romy & Hazen, Terry
Object Type: Report
System: The UNT Digital Library

Alternations of Structure and Functional Activity of Below Ground Microbial Communities at Elevated Atmospheric Carbon Dioxide

The global atmospheric concentration of CO2 has increased by more than 30percent since the industrial revolution. Although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity have been well studied, its influences on belowground microbial communities are poorly understood and controversial. In this study, we showed a significant change in the structure and functional potential of soil microbial communities at eCO2 in a grassland ecosystem, the BioCON (Biodiversity, CO2 and Nitrogen) experimental site (http://www.biocon.umn.edu/) using a comprehensive functional gene array, GeoChip 3.0, which contains about 28,0000 probes and covers approximately 57,000 gene variants from 292 functional gene families involved in carbon, nitrogen, phosphorus and sulfur cycles as well as other functional processes. GeoChip data indicated that the functional structure of microbial communities was markedly different between ambient CO2 (aCO2) and eCO2 by detrended correspondence analysis (DCA) of all 5001 detected functional gene probes although no significant differences were detected in the overall microbial diversity. A further analysis of 1503 detected functional genes involved in C, N, P, and S cycles showed that a considerable portion (39percent) of them were only detected under either aCO2 (14percent) or eCO2 (25percent), indicating that the functional characteristics of the microbial …
Date: May 17, 2010
Creator: He, Zhili; Xu, Meiying; Deng, Ye; Kang, Sanghoon; Wu, Liyou; Van Nostrand, Joy D. et al.
Object Type: Poster
System: The UNT Digital Library
Chemical structure of vanadium-based contact formation on n-AlN (open access)

Chemical structure of vanadium-based contact formation on n-AlN

We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.
Date: May 17, 2010
Creator: Pookpanratana, S.; France, R.; Blum, M.; Bell, A.; Bar, M.; Weinhardt, L. et al.
Object Type: Article
System: The UNT Digital Library
Comparative Genomics Analysis and Phenotypic Characterization of Shewanella putrefaciens W3-18-1: Anaerobic Respiration, Bacterial Microcompartments, and Lateral Flagella (open access)

Comparative Genomics Analysis and Phenotypic Characterization of Shewanella putrefaciens W3-18-1: Anaerobic Respiration, Bacterial Microcompartments, and Lateral Flagella

Respiratory versatility and psychrophily are the hallmarks of Shewanella. The ability to utilize a wide range of electron acceptors for respiration is due to the large number of c-type cytochrome genes present in the genome of Shewanella strains. More recently the dissimilatory metal reduction of Shewanella species has been extensively and intensively studied for potential applications in the bioremediation of radioactive wastes of groundwater and subsurface environments. Multiple Shewanella genome sequences are now available in the public databases (Fredrickson et al., 2008). Most of the sequenced Shewanella strains were isolated from marine environments and this genus was believed to be of marine origin (Hau and Gralnick, 2007). However, the well-characterized model strain, S. oneidensis MR-1, was isolated from the freshwater lake sediment of Lake Oneida, New York (Myers and Nealson, 1988) and similar bacteria have also been isolated from other freshwater environments (Venkateswaran et al., 1999). Here we comparatively analyzed the genome sequence and physiological characteristics of S. putrefaciens W3-18-1 and S. oneidensis MR-1, isolated from the marine and freshwater lake sediments, respectively. The anaerobic respirations, carbon source utilization, and cell motility have been experimentally investigated. Large scale horizontal gene transfers have been revealed and the genetic divergence between these …
Date: May 17, 2010
Creator: Qiu, D.; Tu, Q.; He, Zhili & Zhou, Jizhong
Object Type: Report
System: The UNT Digital Library
Comparative Metagenomics of Freshwater Microbial Communities (open access)

Comparative Metagenomics of Freshwater Microbial Communities

Previous analyses of a microbial metagenome from uranium and nitric-acid contaminated groundwater (FW106) showed significant environmental effects resulting from the rapid introduction of multiple contaminants. Effects include a massive loss of species and strain biodiversity, accumulation of toxin resistant genes in the metagenome and lateral transfer of toxin resistance genes between community members. To better understand these results in an ecological context, a second metagenome from a pristine groundwater system located along the same geological strike was sequenced and analyzed (FW301). It is hypothesized that FW301 approximates the ancestral FW106 community based on phylogenetic profiles and common geological parameters; however, even if is not the case, the datasets still permit comparisons between healthy and stressed groundwater ecosystems. Complex carbohydrate metabolism has been almost entirely lost in the stressed ecosystem. In contrast, the pristine system encodes a wide diversity of complex carbohydrate metabolism systems, suggesting that carbon turnover is very rapid and less leaky in the healthy groundwater system. FW301 encodes many (~;;160+) carbon monoxide dehydrogenase genes while FW106 encodes none. This result suggests that the community is frequently exposed to oxygen from aerated rainwater percolating into the subsurface, with a resulting high rate of carbon metabolism and CO production. When …
Date: May 17, 2010
Creator: Hemme, Chris; Deng, Ye; Tu, Qichao; Fields, Matthew; Gentry, Terry; Wu, Liyou et al.
Object Type: Report
System: The UNT Digital Library
Conservation of Modules but not Phenotype in Bacterial Response to Environmental Stress (open access)

Conservation of Modules but not Phenotype in Bacterial Response to Environmental Stress

Microbes live in changing environments and change their phenotype via gene regulation in response. Although this transcriptional response is important for fitness, very little is known about how it evolves in microbes. We started by asking a number of high-level questions about the evolution of transcriptional phenotype: (1) To what extent is transcriptional response conserved, i.e. do conserved genes respond similarly to the same condition; (2) To what extent are transcriptional modules conserved; and (3) Does there exist a general stress response to a variety of stressors? To illuminate these questions, we analyzed more than 500 microarray experiments across the bacterial domain. We looked for conservation of transcriptional regulation both in close sister species and vastly divergent clades. In addition, we produced and analyzed an extensive in-house compendium of environmental stress data in three metal-reducing bacteria.
Date: May 17, 2010
Creator: Timberlake, Sonia; Joachimiak, Marcin; Joyner, Dominique; Chakraborty, Romy; Baumohl, Jason; Dehal, Paramvir et al.
Object Type: Report
System: The UNT Digital Library
Design of a Pulsed Flux Concentrator for the ILC Positron Source (open access)

Design of a Pulsed Flux Concentrator for the ILC Positron Source

The Positron Source for the International Linear Collider requires an optical matching device after the target to increase the capture efficiency for positrons. Pulsed flux concentrators have been used by previous machines to improve the capture efficiency but the ILC has a 1 ms long pulse train which is too long for a standard flux concentrator. A pulsed flux concentrator with a 40 ms flat top was created for a hyperon experiment in 1965 which used liquid nitrogen cooling to reduce the resistance of the concentrating plates and extend the lifetime of the pulse. We report on a design for a 1 ms device based on this concept.
Date: May 17, 2010
Creator: Gronberg, J.; Abbott, R.; Brown, C.; Javedani, J.; Piggott, W. T. & Clarke, J.
Object Type: Article
System: The UNT Digital Library
Development of a Model, Metal-reducing Microbial Community for a System Biology Level Assessment of Desulfovibrio vulgaris as part of a Community (open access)

Development of a Model, Metal-reducing Microbial Community for a System Biology Level Assessment of Desulfovibrio vulgaris as part of a Community

One of the largest experimental gaps is between the simplicity of pure cultures and the complexity of open environmental systems, particularly in metal-contaminated areas. These microbial communities form ecosystem foundations, drive biogeochemical processes, and are relevant for biotechnology and bioremediation. A model, metal-reducing microbial community was constructed as either syntrophic or competitive to study microbial cell to cell interactions, cell signaling and competition for resources. The microbial community was comprised of the metal-reducing Desulfovibrio vulgaris Hildenborough and Geobacter sulfurreducens PCA. Additionally, Methanococcus maripaludis S2 was added to study complete carbon reduction and maintain a low hydrogen partial pressure for syntrophism to occur. Further, considerable work has been published on D. vulgaris and the D. vulgaris/ Mc. maripaludis co-culture both with and without stress. We are extending this work by conducting the same stress conditions on the model community. Additionally, this comprehensive investigation includes physiological and metabolic analyses as well as specially designed mRNA microarrays with the genes for all three organisms on one slide so as to follow gene expression changes in the various cultivation conditions as well as being comparable to the co- and individual cultures. Further, state-of -the-art comprehensive AMT tag proteomics allows for these comparisons at the …
Date: May 17, 2010
Creator: Elias, Dwayne; Schadt, Christopher; Miller, Lance; Phelps, Tommy; Brown, S. D.; Arkin, Adam et al.
Object Type: Report
System: The UNT Digital Library
Development of Extraction Techniques for the Detection of Signature Lipids from Oil (open access)

Development of Extraction Techniques for the Detection of Signature Lipids from Oil

Pure cultures, including Desulfovibrio vulgaris and Methanococcus maripaludus, were combined with model oil samples and oil/diesel mixtures to optimize extraction techniques of signature lipids from oil in support of investigation of microbial communities in oil deposit samples targets for microbial enhanced hydrocarbon recovery. Several techniques were evaluated, including standard phospholipid extraction, ether linked lipid for Archaeal bacterial detection, and high pressure extractiontechniques. Recovery of lipids ranged from 50-80percent as compared to extraction of the pure culture. Extraction efficiency was evaluated by the use of internal standards. Field samples will also be tested for recovery of signature lipids with optimized extraction techniques.
Date: May 17, 2010
Creator: Borglin, Sharon; Geller, Jil; Chakraborty, Romy; Hazen, Terry & Mason, Olivia
Object Type: Report
System: The UNT Digital Library
Development of High Average Power Lasers for the Photon Collider (open access)

Development of High Average Power Lasers for the Photon Collider

The laser and optics system for the photon collider seeks to minimize the required laser power by using an optical stacking cavity to recirculate the laser light. An enhancement of between 300 to 400 is desired. In order to achieve this the laser pulses which drive the cavity must precisely match the phase of the pulse circulating within the cavity. We report on simulations of the performance of a stacking cavity to various variations of the drive laser in order to specify the required tolerances of the laser system. We look at the behavior of a simple four mirror cavity as shown in Fig. 1. As a unit input pulse is applied to the coupling mirror a pulse begins to build up in the interior of the cavity. If the drive pulses and the interior pulse arrive at the coupling mirror in phase the interior pulse will build up to a larger value. The achievable enhancement is a strong function of the reflectivity of the cavities. The best performance if attained when the reflectivities of the input coupler is matched to the internal reflectivities of the cavity. In Fig. 2 we show the build up of the internal pulse after …
Date: May 17, 2010
Creator: Gronberg, J; Stuart, B & Seryi, A
Object Type: Article
System: The UNT Digital Library