Anomalous Electron Transport Due to Multiple High Frequency Beam Ion Driven Alfven Eigenmode (open access)

Anomalous Electron Transport Due to Multiple High Frequency Beam Ion Driven Alfven Eigenmode

We report on the simulations of recently observed correlations of the core electron transport with the sub-thermal ion cyclotron frequency instabilities in low aspect ratio plasmas of the National Spherical Torus Experiment (NSTX). In order to model the electron transport of the guiding center code ORBIT is employed. A spectrum of test functions of multiple core localized Global shear Alfven Eigenmode (GAE) instabilities based on a previously developed theory and experimental observations is used to examine the electron transport properties. The simulations exhibit thermal electron transport induced by electron drift orbit stochasticity in the presence of multiple core localized GAE.
Date: July 13, 2010
Creator: Gorelenkov, N. N.; Stutman, D.; Tritz, K.; Boozer, A.; Delgardo-Aparicio, L.; Fredrickson, E. et al.
Object Type: Report
System: The UNT Digital Library
ARM Climate Research Facility Monthly Instrument Report June 2010 (open access)

ARM Climate Research Facility Monthly Instrument Report June 2010

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: July 13, 2010
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
Borated Materials and Components for Nuclear Shielding and Waste Contamination Applications. Final Crada Report. (open access)

Borated Materials and Components for Nuclear Shielding and Waste Contamination Applications. Final Crada Report.

None
Date: July 13, 2010
Creator: Ehst, D. & Division, Nuclear Engineering
Object Type: Report
System: The UNT Digital Library
Characterization of microbial communities in subsurface nuclear blast cavities of the Nevada Test Site (open access)

Characterization of microbial communities in subsurface nuclear blast cavities of the Nevada Test Site

This US Department of Energy (DOE) Environmental Remediation Sciences Project (ERSP) was designed to test fundamental hypotheses concerning the existence and nature of indigenous microbial populations of Nevada Test Site subsurface nuclear test/detonation cavities. Now called Subsurface Biogeochemical Research (SBR), this program’s Exploratory Research (ER) element, which funded this research, is designed to support high risk, high potential reward projects. Here, five cavities (GASCON, CHANCELLOR, NASH, ALEMAN, and ALMENDRO) and one tunnel (U12N) were sampled using bailers or pumps. Molecular and cultivation-based techniques revealed bacterial signatures at five sites (CHANCELLOR may be lifeless). SSU rRNA gene libraries contained diverse and divergent microbial sequences affiliated with known metal- and sulfur-cycling microorganisms, organic compound degraders, microorganisms from deep mines, and bacteria involved in selenate reduction and arsenite oxidation. Close relatives of Desulforudis audaxviator, a microorganism thought to subsist in the terrestrial deep subsurface on H2 and SO42- produced by radiochemical reactions, was detected in the tunnel waters. NTS-specific media formulations were used to culture and quantify nitrate-, sulfate-, iron-reducing, fermentative, and methanogenic microorganisms. Given that redox manipulations mediated by microorganisms can impact the mobility of DOE contaminants, our results should have implications for management strategies at this and other DOE sites.
Date: July 13, 2010
Creator: Moser, Duane P.; Czerwinski, Ken; Russell, Charles E. & Zavarin, Mavrik
Object Type: Report
System: The UNT Digital Library
Detoxification of Outfall Water Using Natural Organic Matter (open access)

Detoxification of Outfall Water Using Natural Organic Matter

To protect stream organisms in an ephemeral stream at the Savannah River Site, a proposed National Pollutant Discharge Elimination System (NPDES) permit reduced the copper limit from 25 {micro}g/l to 6 {micro}g/l at Outfall H-12. Efforts to reduce copper in the wastewater and stormwater draining to this outfall did not succeed in bringing copper levels below this limit. Numerous treatment methods were considered, including traditional methods such as ion exchange and natural treatment alternatives such as constructed wetlands and peat beds, all of which act to remove copper. However, the very low target metal concentration and highly variable outfall conditions presented a significant challenge for these treatment technologies. In addition, costs and energy use for most of these alternatives were high and secondary wastes would be generated. The Savannah River National Laboratory developed an entirely new 'detoxification' approach to treat the outfall water. This simple, lower-cost detoxification system amends outfall water with natural organic matter to bind up to 25 {micro}g/l copper rather than remove it, thereby mitigating its toxicity and protecting the sensitive species in the ecosystem. The amendments are OMRI (Organic Materials Review Institute) certified commercial products that are naturally rich in humic acids and are commonly used …
Date: July 13, 2010
Creator: Halverson, N.; Looney, B.; Millings, M.; Nichols, R.; Noonkester, J. & Payne, B.
Object Type: Article
System: The UNT Digital Library
Ecological Monitoring and Compliance Program 2009 Report (open access)

Ecological Monitoring and Compliance Program 2009 Report

The Ecological Monitoring and Compliance Program (EMAC), funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, monitors the ecosystem of the Nevada Test Site and ensures compliance with laws and regulations pertaining to NTS biota. This report summarizes the program’s activities conducted by National Security Technologies, LLC, during calendar year 2009. Program activities included (a) biological surveys at proposed construction sites, (b) desert tortoise compliance, (c) ecosystem mapping and data management, (d) sensitive plant species monitoring, (e) sensitive and protected/regulated animal monitoring, (f) habitat monitoring, (g) habitat restoration monitoring, and (h) monitoring of the Nonproliferation Test and Evaluation Complex. During 2009, all applicable laws, regulations, and permit requirements were met, enabling EMAC to achieve its intended goals and objectives.
Date: July 13, 2010
Creator: Hansen, J. Dennis; Anderson, David C.; Hall, Derek B.; Greger, Paul D. & Ostler, W. Kent
Object Type: Report
System: The UNT Digital Library
Fabrication and current optical performance of a large diamond-machined ZnSe immersion grating (open access)

Fabrication and current optical performance of a large diamond-machined ZnSe immersion grating

None
Date: July 13, 2010
Creator: Ikeda, Y.; Kobayashi, N.; Kuzmenko, P. J.; Little, S. L.; Yasui, C.; Kondo, S. et al.
Object Type: Article
System: The UNT Digital Library
High Efficiency Engine Technologies Program (open access)

High Efficiency Engine Technologies Program

Caterpillar's Product Development and Global Technology Division carried out a research program on waste heat recovery with support from DOE (Department of Energy) and the DOE National Energy Technology Laboratory. The objective of the program was to develop a new air management and exhaust energy recovery system that would demonstrate a minimum 10% improvement in thermal efficiency over a base heavy-duty on-highway diesel truck engine. The base engine for this program was a 2007 C15 15.2L series-turbocharged on-highway truck engine with a LPL (low-pressure loop) exhaust recirculation system. The focus of the program was on the development of high efficiency turbomachinery and a high efficiency turbocompound waste heat recovery system. The focus of each area of development was as follows: (1) For turbine stages, the focus was on investigation and development of technologies that would improve on-engine exhaust energy utilization compared to the conventional radial turbines in widespread use today. (2) For compressor stages, the focus was on investigating compressor wheel design parameters beyond the range typically utilized in production, to determine the potential efficiency benefits thereof. (3) For turbocompound, the focus was on the development of a robust bearing system that would provide higher bearing efficiencies compared to systems …
Date: July 13, 2010
Creator: Kruiswyk, Rich
Object Type: Report
System: The UNT Digital Library
Low Emission Advanced Power Cycle. Final CRADA Report. (open access)

Low Emission Advanced Power Cycle. Final CRADA Report.

Today's gas turbines are based on the Brayton Cycle in which heat is added to the working fluid at constant pressure. An alternate approach, the Humphrey cycle, provides a higher theoretical thermal efficiency by adding heat at constant, or near constant volume. A few practical examples of such engines appeared in the mid 1900's, but they were largely superseded by the Brayton engine. Although the conventional gas turbine has been developed to a high level of efficiency and reliability, significant improvements in performance are becoming increasingly costly to obtain. Efficiencies of compressors, turbines and combustors are approaching theoretical limits. Cooling and materials technologies continue to improve but higher cycle temperatures may be limited by NOx emissions. While heat exchangers, intercoolers and other features improve cycle efficiency they add significantly to the cost, weight and volume of the basic engine and for flight applications may always be impractical. For these reasons there has been renewed interest in recent years in the constant volume Humphrey cycle focusing mainly on pulsing systems in which heat is added by a rapid series of detonations. Variations on this basic scheme are being evaluated for aircraft propulsions systems. General Electric has established a joint program with …
Date: July 13, 2010
Creator: Tentner, A. & Division, Nuclear Engineering
Object Type: Report
System: The UNT Digital Library
Metal Interconnect Materials for Solid Oxide Fuel Cells. Final Crada Report. (open access)

Metal Interconnect Materials for Solid Oxide Fuel Cells. Final Crada Report.

None
Date: July 13, 2010
Creator: Ehst, D. & Division, Nuclear Engineering
Object Type: Report
System: The UNT Digital Library
Model for Initiation of Quality Factor Degradation at High Accelerating Fields in Superconducting Radio-Frequency Cavaties (open access)

Model for Initiation of Quality Factor Degradation at High Accelerating Fields in Superconducting Radio-Frequency Cavaties

A model for the onset of the reduction in SRF cavity quality factor, the so-called Q-drop, at high accelerating electric fields is presented. Since magnetic fields at the cavity equator are tied to accelerating electric fields by a simple geometric factor, the onset of magnetic flux penetration determines the onset of Q-drop. We consider breakdown of the surface barrier at triangular grooves to predict the magnetic field of first flux penetration H{sub pen}. Such defects were argued to be the worst case by Buzdin and Daumens, [1998 Physica C 294 257], whose approach, moreover, incorporates both the geometry of the groove and local contamination via the Ginzburg-Landau parameter {kappa}. Since previous Q-drop models focused on either topography or contamination alone, the proposed model allows new comparisons of one effect in relation to the other. The model predicts equivalent reduction of H{sub pen} when either roughness or contamination were varied alone, so smooth but dirty surfaces limit cavity performance about as much as rough but clean surfaces do. Still lower H{sub pen} was predicted when both effects were combined, i.e. contamination should exacerbate the negative effects of roughness and vice-versa. To test the model with actual data, coupons were prepared by …
Date: July 13, 2010
Creator: Dzyuba, A.; U., /Fermilab /Novosibirsk State; Romanenko, A.; /Fermilab & Cooley, L. D.
Object Type: Article
System: The UNT Digital Library